wt/json
1
0 Fork 0
mirror of https://github.com/nlohmann/json.git synced 2026-10-21 11:29:53 +00:00
Code Issues Packages Projects Releases Wiki Activity

Compare commits

base: wt/json:f81cfafd050a67f34c76594bdb08cd962820e295
wt/json:develop wt/json:claude/fix-issue-3989-db7e45 wt/json:gh-pages wt/json:perf/dom-move-keys wt/json:perf/lexer-dispatch wt/json:perf/lexer-simd-strings wt/json:claude/test-compilation-speed-993125 wt/json:claude/todo-191-plan-508110 wt/json:json-view/15-view-bench wt/json:ci/shard-vs2019-appveyor wt/json:perf/value-operations-speedup wt/json:fix/json_pointer_create_object_5357 wt/json:master
wt/json:v3.12.0 wt/json:v3.11.3 wt/json:v3.11.2 wt/json:v3.11.1 wt/json:v3.11.0 wt/json:v3.10.5 wt/json:v3.10.4 wt/json:v3.10.3 wt/json:v3.10.2 wt/json:v3.10.1 wt/json:v3.10.0 wt/json:v3.9.1 wt/json:v3.9.0 wt/json:v3.8.0 wt/json:v3.7.3 wt/json:v3.7.2 wt/json:v3.7.1 wt/json:v3.7.0 wt/json:v3.6.1 wt/json:3.6.1 wt/json:v3.6.0 wt/json:v3.5.0 wt/json:v3.4.0 wt/json:v3.3.0 wt/json:3.3.0 wt/json:v3.2.0 wt/json:3.2.0 wt/json:v3.1.2 wt/json:3.1.2 wt/json:v3.1.1 wt/json:v3.1.0 wt/json:3.1.0 wt/json:v3.0.1 wt/json:3.0.1 wt/json:v3.0.0 wt/json:3.0.0 wt/json:v2.1.1 wt/json:2.1.1 wt/json:v2.1.0 wt/json:2.1.0 wt/json:v2.0.10 wt/json:2.0.10 wt/json:v2.0.9 wt/json:2.0.9 wt/json:v2.0.8 wt/json:2.0.8 wt/json:v2.0.7 wt/json:v2.0.6 wt/json:v2.0.5 wt/json:v2.0.4 wt/json:v2.0.3 wt/json:v2.0.2 wt/json:v2.0.1 wt/json:v2.0.0 wt/json:v1.1.0 wt/json:v1.0.0 wt/json:v1.0.0-rc1
..
compare: wt/json:perf/lexer-dispatch
wt/json:claude/fix-issue-3989-db7e45 wt/json:gh-pages wt/json:perf/dom-move-keys wt/json:perf/lexer-dispatch wt/json:perf/lexer-simd-strings wt/json:develop wt/json:claude/test-compilation-speed-993125 wt/json:claude/todo-191-plan-508110 wt/json:json-view/15-view-bench wt/json:ci/shard-vs2019-appveyor wt/json:perf/value-operations-speedup wt/json:fix/json_pointer_create_object_5357 wt/json:master
wt/json:v3.12.0 wt/json:v3.11.3 wt/json:v3.11.2 wt/json:v3.11.1 wt/json:v3.11.0 wt/json:v3.10.5 wt/json:v3.10.4 wt/json:v3.10.3 wt/json:v3.10.2 wt/json:v3.10.1 wt/json:v3.10.0 wt/json:v3.9.1 wt/json:v3.9.0 wt/json:v3.8.0 wt/json:v3.7.3 wt/json:v3.7.2 wt/json:v3.7.1 wt/json:v3.7.0 wt/json:v3.6.1 wt/json:3.6.1 wt/json:v3.6.0 wt/json:v3.5.0 wt/json:v3.4.0 wt/json:v3.3.0 wt/json:3.3.0 wt/json:v3.2.0 wt/json:3.2.0 wt/json:v3.1.2 wt/json:3.1.2 wt/json:v3.1.1 wt/json:v3.1.0 wt/json:3.1.0 wt/json:v3.0.1 wt/json:3.0.1 wt/json:v3.0.0 wt/json:3.0.0 wt/json:v2.1.1 wt/json:2.1.1 wt/json:v2.1.0 wt/json:2.1.0 wt/json:v2.0.10 wt/json:2.0.10 wt/json:v2.0.9 wt/json:2.0.9 wt/json:v2.0.8 wt/json:2.0.8 wt/json:v2.0.7 wt/json:v2.0.6 wt/json:v2.0.5 wt/json:v2.0.4 wt/json:v2.0.3 wt/json:v2.0.2 wt/json:v2.0.1 wt/json:v2.0.0 wt/json:v1.1.0 wt/json:v1.0.0 wt/json:v1.0.0-rc1
55 Commits
f81cfafd05 .. perf/lexer-dispatch
Author SHA1 Message Date
Niels Lohmann 42d7325d47 Allow the string literal parameter of scan_literal() for clang-tidy 
The parameter takes the literal by array reference so that its length is
a template parameter; this is the same exemption the C array overloads of
to_json() and from_json() have.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:26:54 +02:00
Niels Lohmann d005d0a19c Skip the literal fast path test without exceptions 
The test case compares the error messages of both lexer paths, so it does
not compile with JSON_NOEXCEPTION (the caught exception does not exist).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:26:54 +02:00
Niels Lohmann 999ff1f5ed Match literals without a stack array and keep parser states in bytes 
scan_after_whitespace() built the expected text of true, false, and null in
local std::array objects. With -fstack-protector-strong (the default of
Ubuntu's GCC, among others), a local array gives the function a stack canary
check, which then ran on every token. scan_literal() now takes the text
after the first character as a string literal, with its length as a template
parameter; for contiguous input it compares the rest at once and falls back
to the byte loop on a mismatch, so errors are reported at the same
character. It is out of line, which keeps the token dispatch small.

The parser kept the nesting of arrays and objects in a std::vector<bool>,
whose push_back() GCC calls out of line; it is a std::vector<std::uint8_t>
now.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:26:54 +02:00
Niels Lohmann f05b1d5308 Do not dispatch the SSSE3 string scan with GCC's C++20 modules 
GCC does not keep the target("ssse3") attribute on functions it reads
back from a module interface, so the module build (ci_module_cpp20,
gcc:latest) rejected the intrinsics in vector_utf8_run() with "needs isa
option -mssse3". With __cpp_modules, GCC now uses the portable UTF-8 check
like other compilers without the target attribute; the SSE2 scan stays,
and -mssse3 or more still compiles the SSSE3 check directly. Clang is not
affected.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:26:52 +02:00
Niels Lohmann 6368f55372 Define string_bulk_run_from() only where lexer_string_bulk_run() calls it 
With NEON and simdutf in C++17, lexer_string_bulk_run() takes the
string_bulk_run() path, so the out-of-line helper was unused.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:26:52 +02:00
Niels Lohmann cde239a299 Keep the string scan from slowing down short strings and dump() on Arm 
Three benchmarks were 7-9% slower than develop on Apple M1 (Apple Clang,
-O3 -flto): Accept/jeopardy, Dump/citm_catalog, and Dump/jeopardy.

- dump(): the serializer passes a string without its closing quote, so
  plain_run_end() ran out of input and called the out-of-line NEON loop
  for every string, with fewer than 16 bytes left. The loop is now only
  called for 16 bytes or more.
- accept(): no string of jeopardy.json reaches the vector UTF-8 check,
  yet compiling it into the lexer's scan function made it 5% slower: the
  function runs once per token and now saved more registers and kept a
  stack slot. lexer_string_bulk_run() checks the first four words inline
  and continues out of line, and the serializer keeps string_bulk_run()
  inline, which is faster there.
- The byte that ends a run is read from the scanned buffer instead of
  through get(), which Apple Clang merged with the other get() calls that
  load the read position again right after it was stored (3%).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:26:52 +02:00
Niels Lohmann 50b9e0f874 Scan strings with SSE2, SSSE3, or NEON 
The string fast path found the end of a run of plain characters 8 bytes at
a time (SWAR) and validated non-ASCII text one sequence at a time, calling
validate_one_utf8() out of line for each.

The vector code of json_view's scanner, in the new shared header
detail/input/simd_scan.hpp, now does both 16 bytes at a time: SSE2 finds
the end of a run on x86-64, and the UTF-8 check of Keiser and Lemire runs
with NEON on AArch64 and with SSSE3 on x86-64. SSSE3 is not part of x86-64,
so the check is compiled for it with a function attribute and used when the
CPU has it (cached in a constant-initialized atomic), else the scalar check;
code compiled with -mssse3 skips the CPU check. The first word of a run is
still checked with SWAR (the first four with NEON, where a vector mask
costs more), as most keys and short values end there, and the scalar
helpers are always inlined. On anything else, the scalar code is unchanged.

The new macro JSON_NO_SIMD selects the portable code everywhere, including
the SSE2/NEON digit formatting of the floating-point writer. The lexer tests
now also run with JSON_NO_SIMD and, on x86-64, with -mssse3, and a new test
places every byte that ends a run at each offset across several 16-byte
blocks, after ASCII and after CJK text.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:26:52 +02:00
Niels Lohmann 5e13f834c1 Copy the text of float tokens only when a SAX handler asks for it (#5852) 
After the digits are converted while scanning, copying the token text into
token_buffer (an out-of-line std::string::append) was about 10% of parsing
canada.json. The only reader is the string argument of
json_sax::number_float(), and the library's own handlers
(json_sax_dom_parser, json_sax_dom_callback_parser, json_sax_acceptor)
ignore it.

For contiguous input, the fast path now keeps a pointer to the token in the
input, and get_string() copies it on first use. The parser passes an empty
string to the handlers marked by the new internal trait
sax_ignores_number_text instead of calling get_string(), so json::parse()
and json::accept() never copy float text. User handlers, and
JSON_DIAGNOSTIC_POSITIONS (which reads get_string().size()), still see the
exact text. Keys and strings, which never have pending text, use the
unchecked get_string_token(). Input read through a window into a stream
(std::istream, FILE*) copies the text right away, because the next read may
refill the window.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:26:46 +02:00
Niels Lohmann e13e976801 Accumulate number digits while scanning them (#5851) 
* Accumulate number digits while scanning them

The contiguous number fast path validated a token byte by byte, copied it
into token_buffer, and then converted it in out-of-line functions that
scanned the digits a second time: parse_float_native() called
parse_float_significand(), which returned its result through memory and
called std::any_of (out of line with GCC) twice per number, and
parse_integer_signed() divided by ten on every digit for its overflow check.

scan_number_bulk_contiguous() now accumulates the significand while it
validates the digits, eight at a time where at least eight bytes remain
(is_eight_digits() and parse_eight_digits(), after fast_float). Floats with
at most 19 digits go straight to decimal_to_float(); integers with at most
18 digits are stored without an overflow check (a narrower number type
still rejects values that do not round-trip). Longer tokens take the
existing path. has_nonzero_digit() is a plain loop and
parse_float_significand() is always inlined, which helps that path.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Skip the digit accumulation checks without exceptions

The section compares error messages from both lexer paths and parses
out-of-range numbers, so it does not compile (the caught exception does not
exist) and would abort with JSON_NOEXCEPTION.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Share the significant-digit loop of the integer part and the fraction

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:26:46 +02:00
Niels Lohmann 898e6ee81d Add benchmarks for SAX parsing, value operations, JSON Pointer, and conversions (#5845) 
Squashed onto develop cd6b428ef (CI fixes from #5860). Original commits:

- Add benchmarks for SAX parsing, value operations, JSON Pointer, and conversions
- Time copies together with their destruction in the benchmarks
- Time destroying the json in ToJsonStrings

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:25:42 +02:00
Niels Lohmann ef1cdb59ac Update performance docs for fast std::istream and FILE* parsing (#5875) 
performance.md still claimed streams have no fast path (outdated since #5828).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 12:25:10 +02:00
Niels Lohmann bd5227c2ec Fix silent wrong results for custom number types (#5805) 
* Fix silent wrong results for custom number types

Squashed onto develop cd6b428ef (CI fixes from #5860). Original commits:

- Fix silent wrong results for custom number types
- Fix CI: build the out_of_range.407 message from string_t and fix a link
- Fix CI: diagnostics message, clang-tidy, and MinGW section limit
- Format the out_of_range.407 number without dump()
- Move the std::deque array test out of unit-regression3.cpp
- Fix clang-tidy and clang 3.4/3.5 failures in the custom number type changes
- Fix CI: cast the 128-bit unsigned value explicitly in the integer fast path

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Name the range checks of integer_fits_max/min

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 08:36:31 +00:00
Niels Lohmann 0cbe95ffa2 Speed up writing CBOR and MessagePack, above all integer arrays (#5824) 
* Speed up writing CBOR and MessagePack, above all integer arrays

Squashed onto develop cd6b428ef (CI fixes from #5860). Original commits:

- Append to the output vector through a position-tracking sink
- Write CBOR integers without branching on their sign or size
- Write MessagePack integers without branching on their sign or size
- Use std::array for the integer size class table
- Fix clang-tidy and GCC warnings in the integer array test
- Regenerate the amalgamation

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Convert the streamed bytes explicitly in the binary writer sink tests

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 10:23:48 +02:00
Niels Lohmann 08d7fbb0a1 Read FILE* input with std::fgetc under MemorySanitizer (#5874) 
With glibc and optimization, <stdio.h> turns getc_unlocked into an extern
inline function that reads the stdio buffer (fp->_IO_read_ptr) directly.
glibc, which is not instrumented, fills that buffer, so MemorySanitizer
treats the bytes as uninitialized and reports a false positive when the
parsers read from a FILE* (e.g., the fuzz harness FILE* leg, OSS-Fuzz
575915982). std::fgetc is an opaque call whose result MemorySanitizer treats
as initialized.

Select JSON_UNLOCKED_FILE_IO 0 when compiled with MemorySanitizer. This is a
regression from #5828 and not part of any release.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 10:22:50 +02:00
Niels Lohmann 4155e2938f Write json_view's dump() without a call or conversion per token (#5633) 
* Write json_view's dump() without a call or conversion per token

The default dump() (no indentation, no ensure_ascii) gets its own
writer that makes the same walk and produces the same output:

- the write position stays in a local variable instead of a
  member, so the compiler keeps it in a register across stores
  through aliasing char pointers;
- strings and number tokens are copied with fixed-size 32-byte
  moves wherever enough source bytes remain, instead of one
  memcpy call per token;
- the innermost open container lives in local variables; a stack
  that starts as a local array of 32 entries holds the rest;
- unedited documents are walked through the node array in order,
  and integer tokens are read from the source directly.

On top of that, float tokens of at most 15 significant digits are
written straight from their digits via zmij::to_shortest() and
write_shortest(), without converting to a double and back: such
decimals are farther apart than a double's rounding interval, so
the token's digits are the double's shortest digits. Tokens of
16+ digits, or edited values, still go through decimal_to_float().
The view's own NEON write_decimal() is removed in favor of the
shared writer, and the dump output now grows in 64 KiB steps
instead of being resized to its estimate at once.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix MSVC C4127 and Infer finding in the view serializer

Test the template options through enabled() so that conditions combined
with them are not constant, and mark the nav::value() null dereference
as a false positive like materialize.hpp does.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix out-of-bounds read when dumping a float token of an unchecked image

A float node of an image loaded with image_check::bounds can hold a
token whose bytes are not digits, so its value need not have the digit
count recorded in the node. write_double_at() passed that count to
write_short_decimal(), which indexes its table of powers of ten by it:
an assertion failure in debug builds, an out-of-bounds read in release
builds. Use the counted overload only if the value has exactly that many
digits, otherwise count them.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Tidy the view serializer: doxygen block placement, enabled() for a constant

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Use a named document in the dump test: root() of a temporary does not compile

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Test write_short_decimal and powers_of_ten_16 against to_chars

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix clang-tidy 22 findings in unit-to_chars.cpp

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Write doubles from their bits only where double is IEEE 754 binary64

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Split the value and pointer edit tests off unit-json_view_edit.cpp

The MinGW linker of the Windows clang jobs cannot link object files with more
than 32767 sections ("relocation truncated to fit: IMAGE_REL_AMD64_REL32
against `.rdata'"). unit-json_view_edit.cpp has 35409 sections since the fast
dump instantiates more code for editable documents, so its test cases "views
and values", "deeply nested values", "pointers below a null value", and
"strings of other documents are checked" move into
unit-json_view_edit_values.cpp. The helper exception_of_call() that both
files use moves into json_view_test_helpers.hpp.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Move the dump tests of this branch to unit-json_view_dump.cpp

The dump and comparison tests moved to their own file in the dump pull
request; the tests of the fast dump() join them there.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address review: one powers-of-ten table, literal sizes from the type

- dtoa_impl::powers_of_ten() (10^0 to 10^19, one entry per line)
  replaces powers_of_ten_16() and the table of int_pow10()
- put_literal() takes the length of a string literal from its type
- small_stack holds the heap vector by reference
- the growth step of the output buffer is written in hex

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Explain why the growth of the dump's stack is static

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 10:21:30 +02:00
Niels Lohmann 4971200b54 Add images of json_documents: save() and load() (#5632) 
* Add images of json_documents: save() and load()

An image is a document stored so that loading it needs no
parsing: save() writes the node index, the text and the decoded
strings; the static load() reads an image written by save().

load() takes a pointer and size, a borrowed vector, or an owned
rvalue vector; the nodes are copied so they are aligned and can
be edited, while the text and decoded strings stay in the image.

image_check controls how much load() trusts the input: full
checks structure, bounds, strings and numbers, the parser's own
guarantees; bounds checks structure and bounds only; none skips
all checks, for images from a trusted source.

Layout is little-endian only ("NJVI" header, nodes, text, decoded
strings), following the idea of zero-copy formats such as
FlatBuffers and YaFF; the check follows FlatBuffers' Verifier.

New errors: parse_error.116 for a malformed image or a failed
check, type_error.320 for a discarded document or a big-endian
target.

A dedicated fuzzer and 6,000 seeded corruptions, checked under
ASan/UBSan, found and fixed two gaps: unchecked reserved header
fields, and unbounded null/boolean offsets that could make
dump() throw std::length_error.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix MSVC errors in image test and add image_check doc anchor

Move the raw string literal out of the CHECK macro (MSVC preprocessor),
cast 64-bit header fields to std::size_t (C4244 on 32-bit), and give the
image_check section in load.md a real anchor for the mkdocs strict build.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Check each distinct string and float range once in the full image check

The full check scanned the contents of every string node and every float token over its own range, so many nodes pointing to one large range made load() quadratic. The structural walk now only collects the ranges; after it, each kind is sorted and checked once per distinct range. Ranges of one kind that overlap without being identical are rejected, as save() never writes them (nodes that share a value share the whole range). The cost is linear in the size of the image plus sorting the ranges.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Adapt the image tests to named documents and last-wins lookups

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Test that the targets of links never reach an image

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Test lookups in loaded images with duplicate and colliding keys

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Release the list of large objects once load() has built the indexes

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Test that invalid UTF-8 of a loaded image is not copied into an editable document

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Document that editable documents refuse invalid UTF-8 copied from a loaded image

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Expect first-wins lookups in the image tests

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Avoid useless casts of header fields in the image tests

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix clang-tidy 22 findings in unit-json_view_image.cpp and image.hpp

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix MSVC C4244 and C2017 in the image test

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix the indentation of a loop in the image test

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make json_view.hpp pass include-what-you-use

ci_single_binaries runs IWYU with --error on every header. For json_view.hpp
it suggested adding <array> (std::array is used), the headers that json.hpp
already provides (abi_config, abi_macros, input_adapters, json_pointer,
cpp_future, string_concat, value_t, json_fwd), and <version> for
std::nullptr_t, and removing <cstddef>.

- include <array>
- keep <cstddef> (nullptr_t, size_t; IWYU attributes them to <version> and <cstring>)
- tell IWYU not to suggest the headers that json.hpp provides: the amalgamated
  json_view.hpp only includes json.hpp, so including them here would duplicate
  their definitions
- drop edit_storage.hpp, which edit.hpp includes

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Silence a clang-tidy C++17 finding in the image test

bugprone-suspicious-stringview-data-usage flags data() of the source view
under C++17, although the length is passed and checked by the REQUIRE
before it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Build the image link test without exceptions

load_result() exists only with exceptions; with JSON_NOEXCEPTION the test
loads the image with the check directly (a failed check aborts).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Follow the renames from the review of the view builder

The review of #5620 renamed document_data's tape/tape_size/tape_cap to
nodes/node_count/node_capacity and made the decode arena a
std::vector<char>; adapt the code of this change to it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Rename the emit lambda in the image writer for Qt compatibility

Qt defines emit as an empty macro, so a Qt header included before
json_view.hpp broke the lambda's declaration (see #5865). The slots
variables in the image tests are renamed as well.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the review of json_document images

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 10:21:29 +02:00
Niels Lohmann 823eee3b59 Add editable json_documents: set, push_back, insert, and erase (#5630) 
* Add editable json_documents: set, push_back, insert, and erase

basic_json_document gets a second template parameter, Editable
(false by default), plus the aliases json_editable_document,
json_editable_view, ordered_json_editable_document and
ordered_json_editable_view.

Editable documents can change values and structure without
rewriting the source text: set()/push_back() on values, keys,
array indices and JSON pointers; insert() before an array
element; erase() of an object key, array index or JSON pointer.

New values and element sequences go into edit storage that the
document owns and never moves, so views keep referring to their
value across edits and a parsed node never moves. Read-only
documents walk the plain node array and are unaffected.

Strings are checked for UTF-8 on entry, so dump() of an editable
document never throws type_error.316. Binary values cannot be
stored (type_error.319).

A seeded differential test applies random edits to an editable
document and to the equivalent ordered_json and compares both
after every step.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix old clang and MSVC C4127 in editable json documents

Value-initialize the const std::less in find_parent (clang 3.4/3.6 do not
implement DR 253), and test the Editable template argument through a
function to avoid MSVC C4127.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Copy nested values into a document without recursion

Counting and copying the nodes of a view or a basic_json value into an
editable document recursed once per nesting level, so that a deeply
nested value overflowed the stack. The four functions now walk the value
with an explicit stack, as materialize() does.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Do not leave a half-assigned container when set_moved() throws

assign() rewrote the kind, length and extent of a slot before set_moved()
registered its new element sequence. set_moved() can throw
(std::bad_alloc from reserving the bookkeeping vectors) for a slot that
is not moved yet, which left a container without the moved flag that
showed its old children. The bookkeeping is now reserved first
(reserve_moved()), so that nothing after the first write to the slot can
throw. block_of() reserves before it marks anything for the same reason.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Check strings copied from another document for valid UTF-8

An editable document only holds valid UTF-8, but copy_scalar() copied the
strings and keys of a view of another document unchecked. A document of
a weaker check (or a borrowed text that changed after parsing) could
therefore bring ill-formed UTF-8 into it. The copy is checked now, with
the error that dump() reports for the string; copies within the same
document stay unchecked.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Allow the edit arena to grow up to 4 GiB - 1 bytes

append_text() doubled the capacity of the arena and rejected the result
if it exceeded 4 GiB, so that an arena of more than 2 GiB could not grow
even though the 32-bit offsets of nodes address 4 GiB - 1 bytes. The
capacity is now clamped to that limit (text_capacity()), and an append
is rejected only if the bytes themselves do not fit.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Set a null value below a pointer as basic_json does

set(json_pointer, value) turned a null parent into an object for every
last reference token, so "/a/0" and "/a/-" below {"a":null} made
{"a":{"0":1}}, where basic_json's operator[](json_pointer) makes an
array. A null parent now becomes an array for "-" and for digit tokens
(filled with nulls up to the index) and an object otherwise. An invalid
index is reported before the parent changes.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Replace a container by a scalar in constant time once it is linked

Replacing an array or object that spans several nodes by a scalar looks
up its parent from the root (find_parent), which is linear in the size
of the document: setting every element of a 20,000 element array took
more than half a second. The parent only has to switch to links once;
afterward the extent of the replaced value no longer matters. Nodes that
an entry of a moved sequence links to are now marked (node_flags::linked),
and assign() skips the lookup for them.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Update the json_view banner and type_error.319 for editable documents

The banner still described a read-only view, and the documentation of
type_error.319 listed set and push_back only, although insert rejects
binary values as well.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Assign the member that lookups find when set() meets duplicate keys

An editable document reads the last member of a repeated key (as the
read-only document does), but set(object, key, value) assigned the first
one: a view taken from object[key] before the call did not show the new
value. It now assigns the last member's value, keeps the key at the
position of its first occurrence (where materialize() puts it), and drops
the other members.

The seeded differential test now also edits documents whose objects
repeat keys and compares every lookup (operator[], at, find, value,
contains, count, and JSON pointers) with the parsed basic_json value.
A targeted test covers duplicates before and after edits that move the
object, in large objects with an index, in moved arrays, and in values
copied from other documents.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Assign the first member when set() meets duplicate keys again

Lookups find the first member of a repeated key again, so set(object, key,
value) assigns that member (keeping the key where it is) and drops the
others, as documented before, and a view taken from object[key] shows the
new value. This undoes the code and documentation changes of 5cbb8e6d6.
Lookups in edited objects (navigation of editable documents) stop at the
first match, like those of parsed objects.

The tests that commit added expect the first member from lookups now. In the
seeded differential test, the documents with repeated keys repeat them after
the real members; the reference holds the first members, which the edits
address and the lookups are compared with, while materialize() is compared
with what parse() makes of the document's dump.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix MSVC C4127 in the lookups of editable json documents

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix clang-tidy 22 findings in the json_view headers

Silence bugprone-casting-through-void for the SSE loads (a reinterpret_cast
would trip -Wcast-align=strict), use auto for a cast initialiser, add
parentheses to a mixed expression, and name bugprone-std-namespace-modification
in the NOLINTs of the tuple_size/tuple_element specialisations.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
(cherry picked from commit 0effbaa7a2)

* Fix clang-tidy 22 findings in unit-json_view_edit.cpp and edit.hpp

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Keep a raw string with a backslash out of a CHECK (MSVC C2017)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make json_view.hpp pass include-what-you-use

ci_single_binaries runs IWYU with --error on every header. For json_view.hpp
it suggested adding <array> (std::array is used), and the headers that json.hpp
already provides (abi_config, abi_macros, input_adapters, json_pointer,
cpp_future, string_concat, value_t, json_fwd), plus <version> for
std::nullptr_t, and removing <cstddef> and edit_storage.hpp.

- include <array>
- keep <cstddef> (nullptr_t, size_t; IWYU attributes them to <version> and <cstring>)
- tell IWYU not to suggest the headers that json.hpp provides: the amalgamated
  json_view.hpp only includes json.hpp, so including them here would duplicate
  their definitions
- drop edit_storage.hpp, which edit.hpp includes

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Keep the view's edit headers clean for clang-tidy in C++17 mode

clang-tidy 22 checks the headers with -std=gnu++17 as well, where it asks
for a transparent comparator and std::make_unique. The regions map uses its
default comparator, and the allocation of the edit state keeps new (the
library is C++11) with a NOLINT.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Follow the renames from the review of the view builder

The review of #5620 renamed document_data's tape/tape_size/tape_cap to
nodes/node_count/node_capacity and made the decode arena a
std::vector<char>; adapt the code of this change to it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Expect count() to count every member in the edit tests

Since #5622, count() counts every member with the key, so documents
with duplicate keys no longer give 1.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Count matching keys as unsigned in the json_view edit tests

Like in the access test, adding the int result of the conditional to a
std::size_t fails -Werror=sign-conversion with GCC.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the review of erase() in editable json documents

From gregmarr's review of #5630:

- invalid_iterator.202 is thrown by overloads 1 and 2 only; the page said
  "every overload" and then excluded 3 in parentheses.
- The note on links says what moves (the links after the removed element,
  as insert() moves them the other way) and that every iterator over the
  container is invalidated, not only those after the removed element.
- edit.hpp compares keys with document_data::key_equals().

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the review of editable json documents

From gregmarr's review of #5630:

- set() with a JSON pointer below a null value checks for "-" before
  scanning the token for digits.
- node_flags::storage is defined as escaped | edited, and the comment on
  document_data::base says that the fourth slot is unused.
- source_extent() names its root check.
- The integer-index overloads of set(), insert(), and erase() use a named
  trait instead of a negated condition, which astyle formats like the
  library's other enable_ifs.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the rest of the review of editable json documents

From gregmarr's review of #5630:

- alloc_nodes() gives a request of half of the next chunk or more a chunk
  of its own, so that the rest of the current chunk stays available for
  smaller requests instead of being abandoned.
- The comments on edit_state, append_text(), and reserve_moved() say that
  views stay valid across every edit (not just the first), that n is 0 for
  empty strings, and why both capacities are checked.
- The architecture page names flag bits 3, 4, and 5 (linked) separately
  and says that a discarded view has no node; erase.md rewords overload 3
  and says why it never throws invalid_iterator.202.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Call alloc_nodes() before reading chunks.back() in the json_view chunk test

The operands of == are unsequenced, and MSVC evaluated
d->edits->chunks.back() before alloc_nodes() added the new chunk, so the
check compared the result with the previous chunk and failed on
msvc-arm64 (Debug and Release).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 10:21:29 +02:00
Niels Lohmann 3ff37ead75 Scan json_view strings with SIMD and index large objects (#5628) 
* Scan json_view strings with SIMD and index large objects

Speed up json_view's parser with SIMD scanning and a hash table
for large objects.

Long runs of string bytes are scanned 16 bytes at a time with NEON
(AArch64, GCC and Clang) and SSE2 (x86-64), both baseline
instruction sets. Keys keep 16 table checks before the vector
loop, because their lengths repeat from record to record; string
values get 8, because their lengths vary more. Non-ASCII text is
validated 16 bytes at a time with simdjson's "lookup4" check
(Keiser and Lemire, 2021), with NEON on AArch64 and, on x86-64,
with SSSE3. SSSE3 is not part of baseline x86-64, so the check is
compiled for SSSE3 with a function attribute and used only where
CPUID reports it, which all x86-64 CPUs since about 2011 do; the
answer is cached in a statically initialized atomic, so there is
no guard of a local static and no global constructor. The same
input is accepted either way. JSON_VIEW_NO_SIMD selects the
portable code.

On x86-64, string runs are now checked vector-first: one SSE2
compare from the first byte finds the end of most keys and short
values, instead of a branch per byte for the first 8-16 bytes.
AArch64 keeps the byte-wise steps, where a NEON mask costs more and
the branches predict well. Entering an object or array no longer
stalls: open() stores the parent's frame field by field instead of
building it on the stack and reading it back with wider loads,
which waited for the narrower stores to retire.

Objects with 128 members or more get an open-addressing hash table
built when the object closes, so operator[], at(), find(),
contains(), count(), value(), and JSON pointers take constant time
on average in such objects; of duplicate keys, the first is kept,
as for the linear search. The idea comes from Boost.JSON.

simdjson is credited in simd.hpp's SPDX block, the README, and
license.md.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix GCC module build and MSVC C4127 in the json_view SIMD code

GCC ignores the target attribute in modules, so the SSSE3 dispatch is
disabled for the module interface (the check stays portable, SSE2 is kept).
Make the 8-vs-16 byte unrolling condition in scan_string_run a
preprocessor/template split to avoid a constant condition (C4127).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Remove an accidentally committed GCC module cache

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Bound the probe length of the large-object hash index

The key hash is not seeded, so keys chosen to collide made building the table quadratic (20,000 colliding keys took 470 ms to parse). A key may now sit at most 64 slots from its home slot; if a key would sit further away, the table is dropped and the object is searched linearly. Lookups stop after the same distance.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Release the spare capacity of the hash index in shrink_to_fit

shrink_to_fit() now trims the tables of large objects like the node array and the decoded strings, and the list of large objects is released as soon as the tables are built.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Use the portable string scan on non-x86 targets that define __SSE2__

WebAssembly with -msse2 defines __SSE2__, but has no <cpuid.h> or x86 intrinsics headers.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Document the hash index number in node::extra

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Keep the last of duplicate keys in the object hash index

Lookups in objects with 128 members or more now return the last member of
a repeated key, like the linear search of smaller objects and like
materialize() and basic_json::parse(). build_object_index let the first
occurrence win, so the same text gave different results depending on the
size of the object.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Keep the first of duplicate keys in the object hash index again

Lookups in objects with 128 members or more return the first member of a
repeated key again, like the linear search of smaller objects. This undoes
the code change of a69542046; its test now expects the first member from
lookups (with and without a table) and the last value from materialize()
and basic_json::parse().

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix clang-tidy 22 findings in the json_view headers

Silence bugprone-casting-through-void for the SSE loads (a reinterpret_cast
would trip -Wcast-align=strict), use auto for a cast initialiser, add
parentheses to a mixed expression, and name bugprone-std-namespace-modification
in the NOLINTs of the tuple_size/tuple_element specialisations.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix clang-tidy 22 findings in unit-json_view.cpp and unit-json_view_builder.cpp

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Avoid GCC useless-cast and strict-overflow warnings in unit-json_view.cpp

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Index strings with size_t in the colliding-keys test (MSVC C4244 on Win32)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make json_view.hpp pass include-what-you-use

ci_single_binaries runs IWYU with --error on every header. For json_view.hpp
it suggested adding <array> (std::array is used), the headers that json.hpp
already provides (abi_config, abi_macros, input_adapters, json_pointer,
cpp_future, string_concat, value_t, json_fwd), and <version> for
std::nullptr_t, and removing <cstddef>.

- include <array>
- keep <cstddef> (nullptr_t, size_t; IWYU attributes them to <version> and <cstring>)
- tell IWYU not to suggest the headers that json.hpp provides: the amalgamated
  json_view.hpp only includes json.hpp, so including them here would duplicate
  their definitions

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Move the dump, comparison, and large-object tests to unit-json_view_dump.cpp

The dump and comparison tests moved to their own file in the dump pull
request; the hash index tests of this branch join them there.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Follow the renames from the review of the view builder

The review of #5620 renamed document_data's tape/tape_size/tape_cap to
nodes/node_count/node_capacity and made the decode arena a
std::vector<char>; adapt the code of this change to it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Rename slots in the object index for Qt compatibility

Qt defines slots as a macro, so a Qt header included before
json_view.hpp broke the declarations of the local variable (see #5865).
The test variable is renamed as well.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the review of the json_view object index and SIMD scan

From gregmarr's review of #5628:

- Docs and comments say that the hash index is one of the object's keys.
- object_index.hpp: conditional_static_cast for the hash, "slot" for the
  table position, no flag for a degenerate table, and a static_assert
  that the smallest indexed object is larger than the probe window.
- scan.hpp unrolls with NLOHMANN_VIEW_REPEAT_FIRST_8/SECOND_8.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Encode JSON_VIEW_NO_SIMD and JSON_VIEW_USE_SSSE3 in the ABI namespace

Both macros select between definitions of the same inline functions, so
translation units that disagree on them violated the ODR. Like the other
ABI-affecting macros, they now add a tag to the inline namespace (_vns and
_vssse3), and the docs replace the "Define consistently" warning with the
usual ABI compatibility note. From gregmarr's review of #5628.

nlohmann_json.natvis covers twice as many tags now, so it lists four times
as many namespaces (14.7 MB instead of 3.4 MB).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Do not include type_traits.hpp directly in the object index

json.hpp, which object_index.hpp already includes, provides it; included
directly, the json_view amalgamation (which only treats nlohmann/json.hpp
as external) copied the json internals into json_view.hpp a second time,
so the fuzzers, which include both single headers, failed with
redefinitions (make_void, integer_sequence, priority_tag, ...).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Compare keys with key_equals() in the object hash index

As the linear lookups do since the second review round of #5622.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 10:21:28 +02:00
Niels Lohmann 4c3a3eb5b5 Add dump() and comparisons to json_view (#5624) 
* Add dump() and comparisons to json_view

Add basic_json_view::dump() and the comparison operators, and read
floats from the parser's digit layout instead of rescanning the
token.

dump(indent, indent_char, ensure_ascii, number_format) writes a
value the way ordered_json::parse(text).dump() writes it for the
same arguments: members in document order, all of them should a
key occur more than once; strings escaped by the same rules, using
the library's scanning kernels; floats written with the library's
to_chars conversion, so the output equals basic_json's byte for
byte; integers copied from the source, where they are already
canonical, except -0, which parse() reads as 0. There is no
error_handler argument, because the view only holds valid UTF-8.
number_format::source copies numbers exactly as they appear in the
source (e.g. "1.50", "1E2", "-0"), which basic_json cannot provide.
operator<< takes the indentation from the stream width, as for
basic_json. The writer walks iteratively, so nesting depth is
limited by memory only.

operator== and operator!= compare two views, or a view and a
basic_json value in either order, by the rules basic_json's
operator== uses: numbers compare by value across their types,
objects compare by their members with duplicate keys resolved as
parse() resolves them, member order matters only where the object
type keeps one, and discarded views compare as discarded basic_json
values do, including under JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON.
Nothing is materialized except single scalars.

While parsing, the view now records where the integer digits, the
fraction digits, and the exponent of a float token are, so floats
and doubles with at most 19 digits are read from that layout with
the library's decimal_to_float() instead of rescanning the token.
Both round correctly, so the values are those of parse(). get<double>(),
materialize(), dump(), and the comparisons all use it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Avoid raw string with escapes inside CHECK macro (MSVC C2017)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Size the dump buffer of a small value by its own extent

The source extent of a value was read from the next node, falling back to the rest of the document when that node held a decoded string. dump() of a small value could thus allocate a buffer as large as the document. Skip a few such nodes, cap the fallback estimate, and shrink a buffer that is much larger than its output.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Hold the documents of the dump and comparison tests in names

root() of a temporary document is deleted: its views would dangle.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Do not shrink the output of dump()

finish() copied the whole output when the buffer was more than twice as
large as the result (citm dump +11%). The tighter source_extent()
estimate already keeps the buffer of a small value small.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Document and test first-wins lookups next to dump() and ==

dump() writes every member and == resolves duplicate keys as parse()
does, whereas lookups find the first member of a duplicate key.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix the clang-tidy 22 findings in json_view and its tests

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Split the dump and comparison tests off unit-json_view.cpp

The MinGW linker of the Windows clang jobs cannot link object files with more
than 32767 sections ("relocation truncated to fit: IMAGE_REL_AMD64_REL32
against `.rdata'"). unit-json_view.cpp reaches that limit as the stack
grows, so its "json_view dump" and "json_view comparison" test cases move
into unit-json_view_dump.cpp. The test generator and has_duplicate_keys()
that both files use move into json_view_test_helpers.hpp.

The new file mentions JSON_HAS_CPP_17, so it is built for C++17 like the file
it was split from.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make json_view.hpp pass include-what-you-use

ci_single_binaries runs IWYU with --error on every header. For json_view.hpp
it suggested adding <array> (std::array is used), the headers that json.hpp
already provides (abi_config, abi_macros, input_adapters, json_pointer,
cpp_future, string_concat, value_t, json_fwd), and <version> for
std::nullptr_t, and removing <cstddef>.

- include <array>
- keep <cstddef> (nullptr_t, size_t; IWYU attributes them to <version> and <cstring>)
- tell IWYU not to suggest the headers that json.hpp provides: the amalgamated
  json_view.hpp only includes json.hpp, so including them here would duplicate
  their definitions

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Follow the renames from the review of the view builder

The review of #5620 renamed document_data's tape/tape_size/tape_cap to
nodes/node_count/node_capacity and made the decode arena a
std::vector<char>; adapt the code of this change to it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Keep the stream includes of json_view.hpp for IWYU

json_view.hpp uses std::istream and std::ostream itself, but IWYU sees
them through the exported json.hpp and asked to remove both includes,
which fails ci_single_binaries (single_json_view).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the review of json_view dump() and comparisons

From gregmarr's review of #5624:

- The output buffer takes string literals without a length.
- write_float() names the IEEE single/double condition once, as the
  library's serializer does.
- equal() checks the types first and compares with !=; the reference to
  the top frame is noted as dangling after pop_back().
- dump.md: one paragraph per case in the notes.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Exclude all json_view test files from Infer's reports

The same std::unique_ptr false positive (USE_AFTER_DELETE) also shows for
two json_documents parsed in one lambda in unit-json_view_dump.cpp
(ci_infer). It affects any test that holds several documents, so the
exclusion now covers tests/src/unit-json_view*.cpp; ASan and Valgrind
cover these tests.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Allow the string literal parameter of the view serializer's put() for clang-tidy

The overload takes the literal by array reference so that its length is a
template parameter, like scan_literal() and the C array overloads of
to_json() and from_json().

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Bind the serializer's frame only after the check for its end

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 10:21:28 +02:00
Niels Lohmann 43e97b629b Add element access, iteration, values, and JSON pointers to json_view (#5622) 
* Add element access, iteration, values, and JSON pointers to json_view

Give basic_json_view the read-only access functions of basic_json:
operator[] and at() with keys and indices, front()/back(), find(),
contains(), count(), begin()/end() and cbegin()/cend(), items()
with structured bindings from C++17 on, and type_name().

Exceptions have the ids and messages of the const functions of
basic_json. Where basic_json has undefined behavior the view
answers safely: operator[] with a missing key or an out-of-range
index returns a discarded view, and front()/back() of an empty
container throw invalid_iterator.214. Objects are iterated in
document order, and all members are visited; duplicate-key lookups
find the first member (as yyjson and simdjson do), while parse(),
materialize(), and the map conversions keep the last value, as
parse() does. Keys of up to 16 bytes are compared with two
overlapping loads.

Add value conversions: get<T>()/get_to() for arithmetic types,
bool, nullptr_t, strings (std::basic_string copied,
string_view_t without a copy), BasicJsonType, views, std::vector,
and maps with string keys; get_string() for the string without a
copy; number_token() for the number exactly as written in the
source; value() with keys and JSON pointers; and operator[]/at()/
contains() with JSON pointers. Everything else, including types
with from_json(), goes through materialize() of that subtree.
get<T>() of arithmetic types is inlined down to the conversion, so
reading an integer needs no call.

detail::json_pointer_access exposes a pointer's reference tokens
to code outside basic_json.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make view lookups last-wins and chained access safe

* Lookups (operator[], at, find, contains, count, value, JSON pointers)
  return the last member of a duplicate key, as materialize() and
  parse() keep it.
* operator[] on a discarded view returns a discarded view instead of
  throwing, so v["a"]["b"] is safe for a missing "a".
* operator[] and at() take any integer type (not only int and size_t),
  fixing ambiguous calls with unsigned, long, std::int64_t, ...
* Fix the operator[] documentation, which claimed a discarded view for
  a type mismatch where type_error.305 is thrown.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Replace the removed operator bool of basic_json_view in the header and its tests

A view is tested with is_discarded(); the lookups in at(), value() and
contains(json_pointer) and the unit tests no longer rely on the explicit
conversion to bool.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Use named documents in the json_view tests that called root() on a temporary

root() of an rvalue document is deleted, because the views would dangle.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Test discarded views with is_discarded() in the operator[] docs and examples

The explicit conversion to bool of basic_json_view is gone.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Return the first member of duplicate keys from lookups again

Looking up the last member of a duplicate key cannot stop at a match, so
every lookup scanned the whole object (1.6 to 3.4 times slower for small
objects). operator[](key), at, find, value, contains, count, and JSON
pointer resolution return the first member again, as yyjson and simdjson
do; materialize() and get<map>() keep the last value, as parse().

The documentation says so in the feature page and on each lookup page,
and explains how to get the value parse() would give. The integer index
templates and the discarded chaining of operator[] stay.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Do not force-inline the view's functions on MSVC

__forceinline makes MSVC report C4714 for function templates it cannot
inline (get<std::string>), an error under /WX. The forced inlining is
only a performance hint, so use plain inline there.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make json_view.hpp pass include-what-you-use

Mark the includes that are needed by design (json.hpp, the macro
unscope, <tuple> for the tuple_size specialization), take size_t from
<cstring>, and drop the forward declaration of basic_json_document that
the friend declaration makes redundant.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Avoid GCC useless-cast warnings in the integer index tests

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make json_view.hpp pass include-what-you-use

ci_single_binaries runs IWYU with --error on every header. For json_view.hpp
it suggested adding <array> (std::array is used), the headers that json.hpp
already provides (abi_config, abi_macros, input_adapters, json_pointer,
cpp_future, string_concat, value_t, json_fwd), and <version> for
std::nullptr_t, and removing <cstddef>.

- include <array>
- keep <cstddef> (nullptr_t, size_t; IWYU attributes them to <version> and <cstring>)
- tell IWYU not to suggest the headers that json.hpp provides: the amalgamated
  json_view.hpp only includes json.hpp, so including them here would duplicate
  their definitions

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix the clang-tidy 22 findings in json_view and its tests

The same changes as on the dump branch, where they were first made, so
that this branch passes clang-tidy on its own.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Report one-character non-numeric array indices like basic_json in the view

Develop's #5800 made basic_json report a JSON pointer array index such as
"/a" as parse_error.109 instead of out_of_range.404, as longer ones were;
the view's array_index() follows, with "-" and the empty token still
unresolved.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the review of json_view element access

From gregmarr's review of #5622:

- count() counts every member with the key, so count(key) > 1 detects
  duplicate keys; it was contains() as 0/1 before.
- get_to() passes types that get<T>() does not convert directly to
  from_json with the existing value, as basic_json::get_to() does, so that
  a from_json which sets only the fields present keeps the others.
- array_index() checks the empty token and "-" first; the results are
  unchanged.
- Docs: no "if an exception is thrown" where a view never changes
  anything; the borrowed source must also stay unmodified; items() on a
  temporary view is safe; back()/front() notes shortened; the basic_json
  see-also entries say how the view's results can differ.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Count matching keys as unsigned in the json_view access test

The conditional added 1 or 0 as int to a std::size_t, which GCC rejects
with -Werror=sign-conversion (ci_test_standards_gcc).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the second review round of json_view element access

From gregmarr's review of #5622:

- begin()/end(): "a null value or a discarded view iterates as an empty
  range", singular like the primitive case before it.
- The class page's list of function groups has no trailing commas.
- document_data::key_equals() compares a key node with a string, for the
  key comparisons that were spelled out in each lookup.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Write the negated enable_if conditions of json_view with negation<>

With a ! or && in the condition, astyle spaces the whole template
header (template < ... >); detail::negation and a named trait keep it
compact, as the library writes such conditions elsewhere. From gregmarr's
review of #5630.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Keep detail::negation out of json_view.hpp's enable_ifs

include-what-you-use asks json_view.hpp to include
detail/meta/type_traits.hpp for it, which the single header must not do
(the amalgamation would duplicate json's internals). The two conditions of
value() go through a trait in value.hpp, like the others.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 10:21:27 +02:00
Niels Lohmann 122d718330 Add json_document and json_view: node index, parser, and document (#5620) 
* Add json_document and json_view: node index, parser, and document

Add json_document and json_view, a read-only, zero-copy index of a
JSON text, as the first public slice of the zero-copy view (#5295).

A parse produces a flat array of 16-byte nodes in document order,
one per value and one per object key. Strings stay in the source
text; escaped strings are decoded into an arena. Integers are
converted while their digits are in the cache; floats keep only
their digit layout and are converted on read. Containers store the
size of their subtree, so a reader can step over one in constant
time. A document makes a handful of allocations, however many
values it has.

The parser accepts exactly what json::parse accepts, with every
combination of ignore_comments and ignore_trailing_commas, with and
without a trailing NUL, and under JSON_STRICT_NUL_HANDLING. It is
portable C++11 and does not depend on byte order.

basic_json_document adds parse, parse_copy, accept, read (reuses a
document's memory), root, is_discarded, source, owns_source,
node_count, memory_usage, and shrink_to_fit. basic_json_view adds
type, the is_* queries, operator bool, size, empty, materialize,
and source_offset. A parse error throws the same exception
basic_json::parse would throw for the same input, message and
position included.

detail::abi_config keeps JSON_STRICT_NUL_HANDLING and
JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON readable after json.hpp
undefines them, in the ABI namespace so they always match the
basic_json in use.

A NUL byte that ends a // comment is the end of the input, as in
parse() since #5696.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix document_data for old Clang (3.4-3.6)

Drop the empty braced NSDMIs of the std::string members: old Clang
rejects the defaulted constructor when it is used by a member
initializer before the end of the class definition.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Exclude libstdc++'s string_view comparison from the sign-change check

basic_string_view::_S_compare stores the difference of two lengths in a
signed difference_type on purpose, which -fsanitize=integer reports for
every comparison with a shorter view (test-json_view_cpp17).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Reject integer lengths in json_document::parse

parse(ptr, len) compiled: len converted to allow_exceptions, and ptr was
read as a C string, past the end of a buffer without a terminating NUL.
Delete the overloads of parse, parse_copy, accept, and read that take an
integer other than bool where the flags are expected.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Copy const rvalue strings and document the accepted inputs

json_document::parse(std::move(const_string)) failed to compile with
"no matching read_kind": only a non-const rvalue std::string can be moved
from. Treat a const rvalue as a copied byte container.

parse() does not accept everything BasicJsonType::parse() does: a FILE*
and pointers to or arrays of wide characters are rejected at compile time.
List the supported inputs instead.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Remove the conversion to bool from json_view

explicit operator bool meant "refers to a value", which silently differs
from what a basic_json converts to. Use !v.is_discarded() instead.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Delete json_document::root() on temporary documents

auto v = json_document::parse(text).root() compiled and left the view
dangling. Delete the overload for rvalue documents, take a named document
in the tests, and document the lifetime rule.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Store node integers by halves on big-endian targets

The non-little-endian path of the node writer wrote the integer's native
word over len and next, so len got the high half there. Compose and split
the value explicitly (len is the low half, next the high half); the
little-endian path stays a plain memcpy.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Check the node array size for overflow

reserve(n) and the growth of the index computed n * sizeof(node) without a
check, which wraps around on 32-bit targets for inputs of about 1 GiB and
allocates a too small array. Throw std::bad_alloc for a count beyond the
address space and clamp the growth step to it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* State the exact input size limit of json_document

The check rejects inputs of 0xFFFFFFF0 bytes or more, but the exception
message and the documentation said 4 GiB. Name the limit once
(max_input_size), and state 4 GiB minus 16 bytes in the message and the
documentation. Test the limit with a container that only claims the size.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Remove the unused legacy_discarded_value_comparison from abi_config

Nothing reads it: the view does not compare values.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Align the banner comment of json_view.hpp

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fuzz json_document with exact-size buffers and parse options

The fuzzer only parsed a std::string with default options. Also parse an
exact-size byte vector, which has no NUL after its last byte and takes the
bounds-checked path, and derive ignore_comments and ignore_trailing_commas
from the first input byte, comparing against json::parse and json::accept
with the same options.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Give document_data a user-provided constructor

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix clang-tidy findings in unit-json_view_builder.cpp

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Annotate intentional patterns in unit-json_view.cpp for clang-tidy

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Suppress Flawfinder's read() finding on the deleted overload

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Check the steps of the deep-nesting test separately

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make max_input_size a function (GCC -Wunused-const-variable)

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make json_view.hpp pass include-what-you-use

ci_single_binaries runs IWYU with --error on every header. For json_view.hpp
it suggested adding <array> (std::array is used), the headers that json.hpp
already provides (abi_config, abi_macros, input_adapters, json_pointer,
cpp_future, string_concat, value_t, json_fwd), and <version> for
std::nullptr_t, and removing <cstddef>.

- include <array>
- keep <cstddef> (nullptr_t, size_t; IWYU attributes them to <version> and <cstring>)
- tell IWYU not to suggest the headers that json.hpp provides: the amalgamated
  json_view.hpp only includes json.hpp, so including them here would duplicate
  their definitions
- export json.hpp, keep macro_unscope.hpp, and drop the unused forward declaration of the document class

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Read the node array base after emit() in the view builder's open()

emit() moves the node array when it grows, and the subtraction read base
in the same expression, so the order was unspecified. MSVC Release builds
without forced inlining read the old base; the container index then
pointed outside the array and close() wrote out of bounds.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Silence a clang-tidy use-after-move finding in the json_view test

const_text is const, so std::move does not move from it; the second call
is part of the const rvalue test.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Regenerate the amalgamated headers

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the review of the view builder and document

Changes promised in the replies to the review of #5620:

- read() reuses the owned copy: a copied input (an rvalue byte container,
  a stream, FILE*, wide characters, an iterator range) is appended to the
  cleared owned buffer instead of a fresh std::string being move-assigned
  over it. A moved-in std::string still replaces it.
- The error replay runs the library parser with a SAX handler that stores
  nothing and throws the reported exception, instead of
  BasicJsonType::parse(), which built a DOM up to the error.
- Pointers to and arrays of wide characters, and FILE*, take the input
  adapter path (converted to UTF-8 into an owned buffer) instead of
  failing a static_assert. Wide pointers are NUL-terminated.
- Streams are read in blocks through rdbuf() into the buffer, instead of
  character by character through the input adapter; eofbit is set at the
  end, as by the library's stream adapter.
- tape/tape_size/tape_cap are now nodes/node_count/node_capacity.
- The builder's members get descriptive, m_-prefixed names.
- The shallow frame stack is a std::array (in a wrapper with a
  user-provided constructor: -Weffc++ wants the member initialized, and
  value-initializing the 64 frames costs up to 30 % on small documents).
- The value dispatch macro has no NEXT parameter; the switch is left with
  break, and the macro is undefined after its last use.
- literal() and digits_exceed() deduce the length from the string literal;
  each literal has one helper; the two `if (!is_float)` blocks are merged.
- arena_ensure() sits right before the writes; the decode arena is a
  std::vector<char>.
- The builder records the deepest nesting, and materialize() sizes its
  stack from it once (growing it only if a subtree is deeper).
- Comment fixes (hex4, slow_string, the NUL rule, put_utf8, 0 - m, the
  arena resize, grow()) and formatting (macro backslashes, digit cases,
  one power of ten per line, value_t assertion next to is_container()).
- build_with's template parameters follow the builder's order.

Greg's idea of keeping the source offset in `off` and the arena offset in
`next` for escaped strings was measured and not adopted: string access got
7-18 % slower with a select, and 3.5-18 % slower with a branch-free field
pick (Apple M-series, clang -O3), parsing was unchanged.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Apply the review's wording fixes to the json_view documentation

- Copying is disabled because of its cost, not because of two documents
  borrowing the same buffer; the unique_ptr follows from move-only.
- Inputs: streams, FILE*, and wide characters (strings, arrays, pointers)
  are all supported and owned; point to parse_copy() for owned copies.
- The error replay only runs for failing input, builds no values, and is
  skipped with allow_exceptions = false.
- read() writes copied inputs into the previous owned copy.
- Views can dangle like std::string_view, and why there is no
  shared/weak pointer design.
- The 4 GiB limit (16-byte nodes, 16-byte scanner steps), streams being
  read to the end first, which macros apply, why materialize() has no
  source positions, and wording nits (accept() vs basic_json::accept(),
  is_binary, is_discarded, see-also lists, size table, "back into").

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Say that json_view converts integers while parsing

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address the review: null inline nodes, trait spelling, and max() in json_view

- inline_nodes is null when the document has no inline nodes, instead of
  pointing past the end of the allocation; shrink_to_fit() no longer
  passes it to memcpy() for an empty node array
- is_byte_char and is_wide_char use conjunction/disjunction, which
  astyle leaves unspaced
- append_stream() uses (std::max) for the count read

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Include materialize.hpp in the view builder test

The test calls detail::view::materialize(), which only the single header
pulled in; the multiple-header build (JSON_TEST_USING_MULTIPLE_HEADERS)
failed with "'materialize' is not a member of detail::view".

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Rename emit() in the view builder for Qt compatibility

Qt defines emit as an empty macro, so a Qt header included before
json_view.hpp broke the declaration of the builder's emit(), see
issue #5865. It is now called push_node().

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Do not copy an empty run into an unallocated arena

memcpy() must not be passed a null pointer even for zero bytes, which
arena_run() did for an empty run while the arena was still empty
(ci_test_clang_sanitizer: "null pointer passed as argument 1" in
builder.hpp). Only the slow path can see such a run.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Exclude the view builder test from Infer's reports

Infer's std::unique_ptr model confuses the values that the test's build()
helper returns by value and reports USE_AFTER_DELETE for one of them after
the destructor of an unrelated temporary (ci_infer, 12 reports, all in
tests/src/unit-json_view_builder.cpp). AddressSanitizer is clean on the
same tests.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Skip the deleted-overload checks of json_view on MSVC 2015

MSVC 2015 does not treat selecting a deleted function in decltype as a
substitution failure, so is_detected reports the deleted
parse/parse_copy/accept/read(ptr, len) overloads as callable and the
static_asserts in "integer arguments do not compile" fail (AppVeyor
VS2015 jobs). Calling them still fails to compile there. Guard the
negative checks as unit-delete_deprecated_functions.cpp does.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 10:21:27 +02:00
Niels Lohmann a4974e72c1 Run the pull request's natvis generator in the amalgamation check (#5873) 
The check ran generate_natvis.py from the develop checkout and took only
the template from the pull request, so a pull request that changes the
generator (such as #5868, which limits the namespaces to two ABI tags)
could never pass: develop's generator rewrote the committed file. The
check now runs the pull request's generator, which loads its own
template, as the macro_builder step already does.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-21 09:55:40 +02:00
Niels Lohmann a55cae45fd Test that the contiguous fast paths never read outside the input (#5826) 
* Test that the contiguous fast paths never read outside the input

The bulk string scanner, the SWAR searches, the UTF-8 prefix validator,
the 8-digit number loop, the 8-byte indentation skip, and the BSON/BON8
bulk string readers load several bytes at a time from contiguous input.
ASan misses over-reads into the slack of the same heap allocation, and
fuzzers rarely end an input exactly at a page boundary.

The new test copies each input directly in front of, and directly
behind, an inaccessible page (mmap/mprotect on POSIX,
VirtualAlloc/VirtualProtect on Windows), so reading even one byte
outside the input crashes. It covers the string-scan functions directly
and json::parse, accept, sax_parse (with and without comments) and all
binary readers through the public API, with inputs ending at every byte
of strings, escapes, UTF-8 sequences, numbers, literals, indentation
runs, and binary documents. Each result must match parsing the same
input from a std::string.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Rename the reader parameter to avoid a flawfinder false positive

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Make the guard page test work without exceptions and under UBSan

Under JSON_NOEXCEPTION, the error paths abort instead of throwing, so the
outcomes are now computed with allow_exceptions=false there. Copying the
input with std::copy from char to unsigned char tripped Clang's implicit
conversion sanitizer; std::memcpy avoids the conversion.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Test parse_float_native() at the guard page

parse_float_eisel_lemire() was removed by #5738, so the test no longer
compiled. The lexer converts floats from its token buffer, so the JSON
section never places a float token at the page boundary; the section now
calls parse_float_native() for float and double on every complete number
token directly and compares the result bit for bit with converting the
same token from a std::string.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix clang-tidy findings in the guard-page tests

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Convert explicitly between bytes and characters in the guard-page tests

The clang sanitizer job (-fsanitize=integer, x86-64 where char is signed)
reported the implicit char -> unsigned char conversions of std::copy() into
the guarded buffer and of the std::string built from the binary inputs.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-20 22:24:09 +02:00
dependabot[bot] 667e296707 Bump ossf/scorecard-action from 2.4.4 to 2.5.0 (#5870) 
Bumps [ossf/scorecard-action](https://github.com/ossf/scorecard-action) from 2.4.4 to 2.5.0.
- [Release notes](https://github.com/ossf/scorecard-action/releases)
- [Changelog](https://github.com/ossf/scorecard-action/blob/main/RELEASE.md)
- [Commits](https://github.com/ossf/scorecard-action/compare/2d1146689b8cda280b9bc96326124645441f03bc...fa7117db83c52d787ae5a89f350999701505d78e)

---
updated-dependencies:
- dependency-name: ossf/scorecard-action
  dependency-version: 2.5.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
 2026-10-20 22:23:22 +02:00
dependabot[bot] ec2e50e26f Bump cppcheck from 1.5.2 to 1.5.3 in /cmake/requirements (#5850) 
Bumps [cppcheck](https://github.com/msclock/cppcheck-wheel) from 1.5.2 to 1.5.3.
- [Release notes](https://github.com/msclock/cppcheck-wheel/releases)
- [Commits](https://github.com/msclock/cppcheck-wheel/compare/v1.5.2...v1.5.3)

---
updated-dependencies:
- dependency-name: cppcheck
  dependency-version: 1.5.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
 2026-10-20 22:22:10 +02:00
Niels Lohmann 4da932f518 Make parsing from std::istream and FILE* fast (#5828) 
* Make parsing from std::istream and FILE* fast

Squashed onto develop cd6b428ef (CI fixes from #5860). Original commits:

- Let the lexer's bulk fast paths run on a window of the input
- Scan the get area of an input stream in bulk
- Lock a FILE once per parse instead of once per character
- Add benchmarks for parsing from a FILE* and for many values from a stream
- Avoid implicit unsigned char to char conversion in stream tests
- Make file_input_adapter::unlock() safe to call on a moved-from adapter

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Add ABI tags for JSON_DISABLE_STREAM_BULK_SCAN and JSON_DISABLE_UNLOCKED_FILE_IO

Both macros select between two definitions of an input adapter, so
translation units compiled with different settings violated the ODR when
linked together. Like the other ABI-affecting macros, they now append a
tag to the inline namespace: _dsbs and _dufio. Their defaults move to
abi_macros.hpp so that json_fwd.hpp sees them, and the natvis file is
regenerated for the new namespaces.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Skip the exception-only checks of the stream input tests without exceptions

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-19 22:00:58 +02:00
Niels Lohmann a2248ed5d5 Test host-toolchain CI jobs on ubuntu-26.04 (#5867) 
* Run host-toolchain CI jobs on ubuntu-26.04

GitHub moves ubuntu-latest to Ubuntu 26.04 between 2026-10-19 and
2026-11-19 (actions/runner-images#14748). Run the jobs that use the
runner's own compilers and tools on ubuntu-26.04 now to find breakage
before the rollout. Container jobs are unaffected.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Let lcov continue on inconsistent coverage data in the coverage job

On ubuntu-26.04, lcov reports a mismatched end line for a function of the
test helper value_in_range_of_test.hpp in the 32-bit build and stops
(ci_test_coverage). The report only covers the library sources, so ignore
the inconsistency like the mismatch and unused errors before.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-19 22:00:43 +02:00
Niels Lohmann cc8334113c Do not use Qt's keyword macros as identifiers (#5866) 
* Do not use Qt's keyword macros as identifiers

The prefix tree used by unflatten() (#5836) had a member named slots, which
Qt defines as an empty macro, so including a Qt header before this library
failed to compile. Rename it to table and add a test that includes the
library with Qt's keyword macros (slots, signals, emit, foreach, forever)
defined.

Fixes #5865

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Keep the Qt keyword macros in the test from failing -Wunused-macros

Clang (-Werror) rejected the macros that the test defines but the library
must not use, and clang-tidy asked for parentheses around the arguments
of the Q_FOREACH imitation, where the variable is a declaration.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-19 22:00:31 +02:00
Niels Lohmann 0e95fe8200 Split the slowest Valgrind tests out of unit-large_json and unit-bjdata (#5862) 
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-17 08:28:28 +02:00
Niels Lohmann cd6b428ef0 Fix CI failures on develop from the API performance stack (#5860) 
Fixes every CI failure develop has had since the API performance stack (#5831-#5842) was merged: compiler warnings and errors (Clang, GCC 4.9/11, MSVC 2015/2017/2022), clang-tidy, cpplint, Cppcheck, IWYU, the examples check, the no-exceptions, diagnostic-positions, implicit-conversions and strict-NUL test configurations, and the MinGW link (now with LLD).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-16 19:16:21 +02:00
Niels Lohmann 5683f5e024 Define less_general() only without three-way comparison (#5859) 
less_general() (#5840) calls operator<(value_t, value_t), which exists in
C++20 only for GCC. Explicit instantiation of basic_json compiles every
member, so clang-cl and MSVC failed on unit-explicit_instantiation and
unit-regression2 in C++20 mode. Its only caller, operator<, is defined
only without three-way comparison, as it was before #5840.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 22:45:56 +02:00
Niels Lohmann 4da73dc5ff Fix compiler warnings on develop from the API performance stack (#5858) 
These PRs were merged while their CI runs were cancelled, so the warnings
went unnoticed. All of them fail the -Werror builds:

- json_pointer.hpp (#5836): size_t += int under GCC -Wsign-conversion
- binary_reader.hpp (#5839): char_int_type passed as char under GCC
  -Wconversion
- json.hpp (#5838): @throw without a description under clang
  -Wdocumentation
- string_escape.hpp (#5836): escape_into() was inserted between escape()
  and its documentation, so the @return was attached to a void function
- unit-diagnostics.cpp (#5832): clang -Wnrvo in a lambda without an
  explicit return type
- unit-to_json-rvalue.cpp (#5837): GCC -Wnoexcept (C++20) and clang
  -Wunneeded-member-function on the test type

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 22:42:46 +02:00
Niels Lohmann c314cf8bd4 Fix the indentation of the destroy comment in json.hpp (#5857) 
The comment block about destroying the tree without recursion was indented
one level too deep since #5835. make amalgamate reformatted it with astyle,
leaving an unrelated diff in every branch. single_include is unchanged.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 22:25:47 +02:00
Niels Lohmann b41228c227 Fix AppVeyor failures from the Zmij double writer (#5843) 
MSVC 2015 warns C4554 on the shifts with casts in the fractional part
of zmij::to_shortest despite the parentheses; with /WX every target
fails to build. Name the shift amounts as constants instead.

The shortest-digits test built the candidates with one digit fewer via
a stream with std::setprecision(digits.size() - 2); the standard library
of MSVC 2017 ignores a precision of 0, so for two-digit values the
"shorter" candidates were the value itself. Truncate the digits
instead: the value lies within half a unit of the last digit, so the
truncated digits and their successor are the closest candidates.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:08:12 +02:00
Niels Lohmann dcb96e82fb Escape characters below 0x60 from a table straight into the write buffer (#5822) 
* Escape characters below 0x60 from a table straight into the write buffer

When the bulk scanner in dump_escaped_impl() stops at a control
character, a quote or a backslash, that byte used to go through the
UTF-8 decoder and a switch that wrote the escape byte by byte into
string_buffer, which was then copied into write_buffer at the next run.

A byte below 0x60 at a character boundary is a complete code point, so
it now skips the decoder: its escape sequence comes from a 96-entry
table of 8-byte rows (sequence padded with zeros, length in the last
byte), and all 8 bytes are copied straight into write_buffer with one
room check. The check sits inside the existing character-boundary
block, so it runs once per scanner stop and not once per byte; testing
every byte cost about 6% on twitter.json with ensure_ascii.

The switch in the decoder's accept branch lost its cases for
characters below 0x60, which can no longer reach it.

Output is byte-identical. The string-buffer boundary tests now use
\u-escaped non-ASCII characters, since simple escapes no longer reach
string_buffer, and a new test case checks every ASCII character at
every position against a reference escaper.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Avoid raw string literals with backslashes in CHECK macros

MSVC's traditional preprocessor mis-lexes raw string literals inside
macro arguments and reports illegal escape sequences (C2017, C3850).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Sweep invalid UTF-8 at every position through dump()

Compare dump() of strings with ill-formed UTF-8 (stray continuation
bytes, invalid lead bytes, overlong encodings, surrogates, code points
above U+10FFFF, and sequences cut short by ASCII, a quote, a backslash,
a lead byte, or the end of the string) with an independent reference
serializer, for every error handler and with ensure_ascii on and off.
The pattern is put at every position of short strings to cross the
strides of the bulk scanners, and of longer ones to cross the end of the
512-byte string buffer.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:08:10 +02:00
dependabot[bot] c7fd5ac19f Bump the codeql-action group with 4 updates (#5846) 
Bumps the codeql-action group with 4 updates: [github/codeql-action/init](https://github.com/github/codeql-action), [github/codeql-action/autobuild](https://github.com/github/codeql-action), [github/codeql-action/analyze](https://github.com/github/codeql-action) and [github/codeql-action/upload-sarif](https://github.com/github/codeql-action).


Updates `github/codeql-action/init` from 4.38.2 to 4.38.3
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2...24c54180a607b1449ed407dd24f251e4e9147c8d)

Updates `github/codeql-action/autobuild` from 4.38.2 to 4.38.3
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2...24c54180a607b1449ed407dd24f251e4e9147c8d)

Updates `github/codeql-action/analyze` from 4.38.2 to 4.38.3
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2...24c54180a607b1449ed407dd24f251e4e9147c8d)

Updates `github/codeql-action/upload-sarif` from 4.38.2 to 4.38.3
- [Release notes](https://github.com/github/codeql-action/releases)
- [Changelog](https://github.com/github/codeql-action/blob/main/CHANGELOG.md)
- [Commits](https://github.com/github/codeql-action/compare/2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2...24c54180a607b1449ed407dd24f251e4e9147c8d)

---
updated-dependencies:
- dependency-name: github/codeql-action/init
  dependency-version: 4.38.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: codeql-action
- dependency-name: github/codeql-action/autobuild
  dependency-version: 4.38.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: codeql-action
- dependency-name: github/codeql-action/analyze
  dependency-version: 4.38.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: codeql-action
- dependency-name: github/codeql-action/upload-sarif
  dependency-version: 4.38.3
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: codeql-action
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
 2026-10-15 20:05:49 +02:00
dependabot[bot] a678aa6dd7 Bump actions/setup-node from 7.0.0 to 7.1.0 (#5847) 
Bumps [actions/setup-node](https://github.com/actions/setup-node) from 7.0.0 to 7.1.0.
- [Release notes](https://github.com/actions/setup-node/releases)
- [Commits](https://github.com/actions/setup-node/compare/820762786026740c76f36085b0efc47a31fe5020...949feb2413d6458794dcd2491c4babbbce0c15c1)

---
updated-dependencies:
- dependency-name: actions/setup-node
  dependency-version: 7.1.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
 2026-10-15 20:05:39 +02:00
dependabot[bot] 3d93f682a7 Bump step-security/harden-runner from 2.22.0 to 2.22.1 (#5848) 
Bumps [step-security/harden-runner](https://github.com/step-security/harden-runner) from 2.22.0 to 2.22.1.
- [Release notes](https://github.com/step-security/harden-runner/releases)
- [Commits](https://github.com/step-security/harden-runner/compare/351661ca32ac09a36dc5ee2d536e3128f2a3c8ed...ccd8616d44fd3846e67624a50d5aad6d37bf2d25)

---
updated-dependencies:
- dependency-name: step-security/harden-runner
  dependency-version: 2.22.1
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
 2026-10-15 20:05:28 +02:00
dependabot[bot] 1c696dcf05 Bump actions/upload-artifact from 7.0.1 to 7.0.2 (#5849) 
Bumps [actions/upload-artifact](https://github.com/actions/upload-artifact) from 7.0.1 to 7.0.2.
- [Release notes](https://github.com/actions/upload-artifact/releases)
- [Commits](https://github.com/actions/upload-artifact/compare/043fb46d1a93c77aae656e7c1c64a875d1fc6a0a...cf430e030ddbb5b0abf93d22962f4752f3646cd9)

---
updated-dependencies:
- dependency-name: actions/upload-artifact
  dependency-version: 7.0.2
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
 2026-10-15 20:05:17 +02:00
dependabot[bot] 7cd34c62a9 Bump lukka/get-cmake from 4.4.2 to 4.4.4 (#5819) 
Bumps [lukka/get-cmake](https://github.com/lukka/get-cmake) from 4.4.2 to 4.4.4.
- [Release notes](https://github.com/lukka/get-cmake/releases)
- [Changelog](https://github.com/lukka/get-cmake/blob/main/RELEASE_PROCESS.md)
- [Commits](https://github.com/lukka/get-cmake/compare/fffaaafeea488556c2c12dad60690008bc1caacb...a89e43e22a96abafcd7a62db652a65ecd33052c9)

---
updated-dependencies:
- dependency-name: lukka/get-cmake
  dependency-version: 4.4.4
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
 2026-10-15 20:05:07 +02:00
Niels Lohmann eb74fe2ab7 Fuzz the streaming input adapters against the contiguous one (#5827) 
* Fuzz the streaming input adapters against the contiguous one

The fast paths for contiguous input (bulk string scanning, multi-byte
loads, lazy position tracking) are taken only when parsing from a
pointer range; streams and non-contiguous iterators still read byte by
byte. The fuzzer drivers parsed only contiguous input, so a difference
between the two would ship unnoticed.

check_input_adapters() in fuzzer_common.hpp reads the input through a
std::istringstream, a std::list iterator range, and (on POSIX) a FILE*
from fmemopen, and asserts the same value, or the same exception id,
message and byte position, as for the pointer range. All seven drivers
call it; the JSON driver checks parse and accept, each with and without
ignore_comments. It replaces the stream check of the BON8 driver.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Rename the reader parameter to avoid a flawfinder false positive

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:04:57 +02:00
Niels Lohmann 91b9ee2602 Update cppcheck to 1.5.2 (Cppcheck 2.20) and fix its new findings (#5829) 
Cppcheck 2.20 rejects invocations of unknown function-like macros in #if
conditions instead of evaluating them as 0. default_defines.hpp expands
the Hedley macros to the compiler's feature-test operators (__has_attribute
etc.), so define them as 0 in a generated include file.

It also reports a false bufferAccessOutOfBounds in the float overload of
float_from_bits, sizing the parameter as the double overload's; use the
size of the source instead (equal by the static_assert).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:04:46 +02:00
Niels Lohmann ce28c722bc Allow the same type for number_integer_t and number_unsigned_t (#5815) 
* Allow the same type for number_integer_t and number_unsigned_t

basic_json did not compile with NumberUnsignedType == NumberIntegerType
because overloads on both types collided. Such a basic_json now stores
every integer as number_integer: the colliding overloads take a
placeholder type, unsigned C++ integers are converted to number_integer_t,
and value_t::number_unsigned maps to number_integer.

Also fixes two problems this configuration would hit: the unsigned
integer parser accepted values that wrap around to negative numbers, and
dump() overflowed when computing the absolute value of the minimum.

A repeated NumberFloatType gets a static_assert.

Refs #2573

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Use json::with_integers_t in the test and the docs

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* ✅ skip patch test on GCC 5 to avoid internal compiler error

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fix CI: name the unsigned overload type through template parameters

basic_json used number_unsigned_overload_t<basic_json> while the class was
still incomplete. MSVC rejected it as a recursive alias declaration and GCC
4.9, 5 and 7 crashed with an internal compiler error. basic_json now uses
number_unsigned_overload_type<NumberIntegerType, NumberUnsignedType>, which
also makes the GCC 5 workaround in the patch test unnecessary.

Infer reported a null dereference for the number_unsigned case in
from_json, which cannot happen for a basic_json whose number_unsigned_t is
number_integer_t; assert it.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address review: conjunction/negation trait, astyle-friendly alias, docs table order

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:04:42 +02:00
Niels Lohmann 6261d1e432 Construct the JSON Patch exceptions out of line (#5842) 
patch_inplace() built its error messages inline. In particular get_value()
concatenated the context-sensitive "operation 'x'" string on every call, even
when nothing was wrong. The patch exceptions now come from NEVER_INLINE
helpers: the index and key errors reuse basic_json's existing
throw_array_index_out_of_range/throw_key_not_found, and the seven
patch-specific messages get one helper each in detail/exceptions.hpp. Ids
and messages are unchanged, and unit-throw_messages pins them (with and
without JSON_DIAGNOSTICS).

citm_catalog patch: -6.6 % (Apple clang), -9.5 % (GCC 16).
The other remaining throw sites (parser::syntax_error, binary_writer,
serializer, input_adapters, enum_key_duplicate, format_error) were prototyped
and measured: no gain beyond noise, so they stay as they are.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:23 +02:00
Niels Lohmann ed86019a21 Move binary reader error construction out of line (#5839) 
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:23 +02:00
Niels Lohmann 4f11512641 Speed up container destruction, iterator access and diff() (#5835) 
* Speed up container destruction, iterator access and diff()

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Destroy the first levels of a value by recursion

The pointer-reversing walk in destroy_container() avoids the call stack but
moves a value around for every container it visits. Recurse for the first
recursion_depth_limit() levels instead - no allocation, no thread-local, a
bounded frame - and hand anything deeper to the walk. Destroy twitter
0.49 -> 0.36 ms, citm 0.80 -> 0.74 ms (3.12.0: 0.47 / 1.00).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:22 +02:00
Niels Lohmann 6a27b9acb2 Construct remaining hot-path exceptions out of line so core functions inline (#5838) 
* Construct remaining hot-path exceptions out of line so core functions inline

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Move throw_key_not_found() before at_impl()'s comment block

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:22 +02:00
Niels Lohmann 91869983a0 Make the value lifecycle inline-friendly (#5840) 
* Make the value lifecycle inline-friendly

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Compare standard containers without a thread-local depth count

operator== on objects and arrays recursed through the containers' own
operator== and counted the depth in a thread-local variable. Where reading a
thread-local costs a call (macOS), that added about 10% to comparing documents
with many small containers. For the standard containers, walk objects and
arrays directly, compare scalars and strings inline, and pass the depth as an
argument, falling back to compare_iteratively beyond the depth limit. Other
container types keep the previous path.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Address review: owns_memory() helper, leaf compare naming, astyle

- Add detail::owns_memory(value_t), a switch listing every enumerator so
  -Wswitch-enum flags it when a type is added; destroy() and the copy
  constructor use it instead of hand-written comparisons. Clang emits the
  same bitmask test as before.
- Drop the parentheses around the scalar operands in
  JSON_IMPLEMENT_SCALAR_CASES; they are only needed for the container
  operands (#1530), which the comment now says.
- Build equal_bounded_containers from detail::conjunction so astyle no
  longer pads the template brackets.
- Rename equal_scalar() to equal_leaf() and document why it also compares
  strings, unlike JSON_IMPLEMENT_SCALAR_FAST.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:21 +02:00
Niels Lohmann 4530d9681c Fix quadratic parent updates for ordered_json with JSON_DIAGNOSTICS (#5832) 
* Fix quadratic parent updates for ordered_json with JSON_DIAGNOSTICS

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Only trust containers known to keep their elements in place

Address review: decide whether an insertion may have moved the other
members by naming the containers that are known not to, instead of the
ones that are known to.

- detail::has_stable_elements: std::map, std::multimap,
  std::unordered_map and std::unordered_multimap; object_capacity()
  reports 0 for them.
- detail::is_nlohmann_ordered_map: only the real nlohmann::ordered_map
  (which only appends) reports its capacity().
- Any other object type reports unknown_size(), so it gets a full
  set_parents() on every insertion. Before, an object type without
  capacity() was treated as never moving, and one with capacity() (a
  sorted flat map, say) was trusted to move only on reallocation.
- set_parents_after_object_erase() re-parents unless the object type is
  stable; the unused set_parent() is removed.
- Comments say "the object type" instead of "ordered_json".
- New test with an object type that moves its members without changing
  its capacity; it fails without this change.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:21 +02:00
Niels Lohmann ca7740fef2 Move elements when converting rvalue containers to JSON (#5837) 
* Move elements when converting rvalue containers to JSON

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Simplify the rvalue to_json traits

Use negation<disjunction<...>> instead of a conjunction of negations and
keep the template argument lists compact (astyle only keeps the spaced
'< ... >' form when it is written that way).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:20 +02:00
Niels Lohmann 6ba53e63dd Speed up array-to-container from_json (#5833) 
* Speed up array-to-container from_json

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Hint the end when converting an object to a standard container

from_json for map-like containers called emplace() without a hint, which
searches the tree for every key. The keys of the source object are sorted, so
inserting with the end as the hint is constant time, as it was in 3.12.0 via
std::inserter. get<std::map<...>>() of a 25,000 entry object: 4.2 ms -> 3.25 ms
(3.12.0: 3.7 ms).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Fall back to emplace() in object from_json for containers without emplace_hint()

ordered_map has no hinted insert, so the insert(end(), ...) call broke
from_json into types holding an ordered_map (regression test #5122).
Use emplace_hint() where available and plain emplace() otherwise.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:20 +02:00
Niels Lohmann 0a4b3a84ee Speed up JSON pointer parsing, formatting, comparison and lookup (#5836) 
* Speed up JSON pointer parsing, formatting, comparison and lookup

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Restore unflatten() speed after the linear-time rewrite

The prefix tree introduced for linear unflatten() kept a std::map per prefix,
copied each token into it and looked every token up a second time while
creating the values. Replace the per-prefix maps by one open-addressing table
keyed by (parent, token) that refers to the parsed tokens, skip the lookups for
the prefix shared with the previous key (flattened objects are mostly sorted),
and derive the prefix numbers of the second pass from parent links instead of
lookups.

Time and memory stay linear in the pointer depth, and the result is still
independent of the iteration order of the flattened object.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Put [[noreturn]] before __attribute__ on the JSON pointer throw helpers

Clang 18 on Linux rejects a C++11 attribute list after a GNU
__attribute__ ("an attribute list cannot appear here").

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:20 +02:00
Niels Lohmann 0c4e7c103c Make flatten() linear for ordered_json (#5834) 
* Make flatten() linear for ordered_json

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

* Use priority_tag instead of a C-style variadic overload in add_flattened

clang-tidy flags the ellipsis fallback (cert-dcl50-cpp,
modernize-avoid-variadic-functions).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:19 +02:00
Niels Lohmann a6e9785ab6 Look up the key only once in the callback parser's key() (#5831) 
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-15 20:01:19 +02:00
Niels Lohmann 4e294f4b18 Clarify that double is only the default floating-point type in the docs (#5830) 
Follow-up to review comments on #5825: number_float_t uses double
precision only by default, and the stated limits apply to double.
Also say "default type for X_t" instead of "default value for X_t".

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
 2026-10-14 18:28:49 +02:00
186 changed files with 584158 additions and 3713 deletions
Expand all files Collapse all files

No files matched your search

.github/workflows/cancel_closed_pr_runs.yml
+1 -1
View File
@@ -28,7 +28,7 @@ jobs:
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
.github/workflows/check_amalgamation.yml
+19 -20
View File
@@ -22,7 +22,7 @@ jobs:
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -31,13 +31,13 @@ jobs:
mkdir -p ./pr
echo ${{ github.event.number }} > ./pr/number
echo ${{ github.event.pull_request.user.login }} > ./pr/author
- uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
- uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
with:
name: pr
path: pr/
check:
runs-on: ubuntu-latest
runs-on: ubuntu-26.04
env:
MAIN_DIR: ${{ github.workspace }}/main
INCLUDE_DIR: ${{ github.workspace }}/main/single_include/nlohmann
@@ -46,7 +46,7 @@ jobs:
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -77,13 +77,12 @@ jobs:
cd $MAIN_DIR
# Built from this PR's own tools/macro_builder/main.cpp, not a
# develop checkout: unlike amalgamate.py and generate_natvis.py,
# this tool has no other source of truth to check against (its
# own README documents that it must reproduce macro_scope.hpp
# byte for byte), so there is nothing to gain from checking out a
# separate copy, and doing so would make this step fail on a PR
# that adds support for a new dispatch table until that PR itself
# merges to develop.
# develop checkout: unlike amalgamate.py, this tool has no other
# source of truth to check against (its own README documents that
# it must reproduce macro_scope.hpp byte for byte), so there is
# nothing to gain from checking out a separate copy, and doing so
# would make this step fail on a PR that adds support for a new
# dispatch table until that PR itself merges to develop.
TMPDIR=$(mktemp -d ./macro_builder_check.XXXXXX)
c++ -std=c++11 tools/macro_builder/main.cpp -o "$TMPDIR/macro_builder"
"$TMPDIR/macro_builder" > "$TMPDIR/paste.hpp"
@@ -146,14 +145,14 @@ jobs:
- name: Regenerate nlohmann_json.natvis
run: |
cd $MAIN_DIR
# The template is what this check verifies the committed natvis
# file against, so take it from this PR rather than from the
# develop checkout: generate_natvis.py loads the template from its
# own directory, and with develop's copy a PR that changes the
# template could never pass. Like the macro_builder step above,
# this only renders PR content in a job without credentials.
cp tools/generate_natvis/nlohmann_json.natvis.j2 $NATVIS_TOOL_DIR/
python3 $NATVIS_TOOL_DIR/generate_natvis.py $MAIN_DIR
# The generator and its template are what this check verifies the
# committed natvis file against (which namespaces it lists, and
# what each entry looks like), so run this PR's copy rather than
# the develop checkout's: with develop's, a PR that changes either
# could never pass. generate_natvis.py loads the template from its
# own directory. Like the macro_builder step above, this only runs
# PR content in a job without credentials.
python3 tools/generate_natvis/generate_natvis.py $MAIN_DIR
- name: Build patch and check for differences
id: diff
@@ -173,7 +172,7 @@ jobs:
# instead of installing the pinned astyle version locally.
- name: Upload patch
if: steps.diff.outputs.has_diff == 'true'
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
with:
name: amalgamation-patch
path: patch/amalgamation.patch
.github/workflows/check_docs_links.yml
+1 -1
View File
@@ -20,7 +20,7 @@ jobs:
timeout-minutes: 30
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
.github/workflows/cifuzz.yml
+2 -2
View File
@@ -13,7 +13,7 @@ jobs:
runs-on: ubuntu-22.04
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -35,7 +35,7 @@ jobs:
dry-run: false
language: c++
- name: Upload Crash
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
if: failure() && steps.build.outcome == 'success'
with:
name: artifacts
.github/workflows/codeql-analysis.yml
+5 -5
View File
@@ -21,13 +21,13 @@ permissions:
jobs:
CodeQL-Build:
runs-on: ubuntu-latest
runs-on: ubuntu-26.04
permissions:
security-events: write
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -38,14 +38,14 @@ jobs:
# Initializes the CodeQL tools for scanning.
- name: Initialize CodeQL
uses: github/codeql-action/init@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
uses: github/codeql-action/init@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
with:
languages: c-cpp
# Autobuild attempts to build any compiled languages (C/C++, C#, or Java).
# If this step fails, then you should remove it and run the build manually (see below)
- name: Autobuild
uses: github/codeql-action/autobuild@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
uses: github/codeql-action/autobuild@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
- name: Perform CodeQL Analysis
uses: github/codeql-action/analyze@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
uses: github/codeql-action/analyze@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
.github/workflows/comment_check_amalgamation.yml
+1 -1
View File
@@ -20,7 +20,7 @@ jobs:
pull-requests: write
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
.github/workflows/dependency-review.yml
+1 -1
View File
@@ -21,7 +21,7 @@ jobs:
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
.github/workflows/flawfinder.yml
+2 -2
View File
@@ -31,7 +31,7 @@ jobs:
security-events: write
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -47,6 +47,6 @@ jobs:
output: 'flawfinder_results.sarif'
- name: Upload analysis results to GitHub Security tab
uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
uses: github/codeql-action/upload-sarif@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
with:
sarif_file: ${{github.workspace}}/flawfinder_results.sarif
.github/workflows/labeler.yml
+1 -1
View File
@@ -23,7 +23,7 @@ jobs:
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
.github/workflows/publish_documentation.yml
+1 -1
View File
@@ -37,7 +37,7 @@ jobs:
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
.github/workflows/scorecards.yml
+4 -4
View File
@@ -40,7 +40,7 @@ jobs:
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -50,7 +50,7 @@ jobs:
persist-credentials: false
- name: "Run analysis"
uses: ossf/scorecard-action@2d1146689b8cda280b9bc96326124645441f03bc # v2.4.4
uses: ossf/scorecard-action@fa7117db83c52d787ae5a89f350999701505d78e # v2.5.0
with:
results_file: results.sarif
results_format: sarif
@@ -72,7 +72,7 @@ jobs:
# Upload the results as artifacts (optional). Commenting out will disable uploads of run results in SARIF
# format to the repository Actions tab.
- name: "Upload artifact"
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
with:
name: SARIF file
path: results.sarif
@@ -80,6 +80,6 @@ jobs:
# Upload the results to GitHub's code scanning dashboard.
- name: "Upload to code-scanning"
uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
uses: github/codeql-action/upload-sarif@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
with:
sarif_file: results.sarif
.github/workflows/semgrep.yml
+3 -3
View File
@@ -33,10 +33,10 @@ jobs:
security-events: write # for github/codeql-action/upload-sarif to upload SARIF results
actions: read # only required for a private repository by github/codeql-action/upload-sarif to get the Action run status
name: Scan
runs-on: ubuntu-latest
runs-on: ubuntu-26.04
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -65,7 +65,7 @@ jobs:
# Upload SARIF file generated in previous step
- name: Upload SARIF file
uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
uses: github/codeql-action/upload-sarif@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
with:
sarif_file: semgrep.sarif
if: always()
.github/workflows/stale.yml
+1 -1
View File
@@ -16,7 +16,7 @@ jobs:
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
.github/workflows/ubuntu.yml
+32 -32
View File
@@ -25,20 +25,20 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_test_gcc
ci_meson_install:
runs-on: ubuntu-latest
runs-on: ubuntu-26.04
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Check that Meson and pkg-config offer the CMake options
run: make check_build_options
- name: Install Meson
@@ -77,10 +77,10 @@ jobs:
cmake --build build-import-split
ci_infer:
runs-on: ubuntu-latest
runs-on: ubuntu-26.04
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -92,27 +92,27 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_infer
- name: Archive Infer report
if: always()
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
with:
name: infer-report
path: ${{ github.workspace }}/build/build_infer/infer-out/report.txt
if-no-files-found: ignore
ci_static_analysis_ubuntu:
runs-on: ubuntu-latest
runs-on: ubuntu-26.04
strategy:
matrix:
target: [ci_test_single_header, ci_cppcheck, ci_cpplint, ci_reproducible_tests, ci_non_git_tests, ci_offline_testdata, ci_reuse_compliance, ci_test_valgrind]
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -123,7 +123,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
@@ -142,7 +142,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
@@ -168,17 +168,17 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ${{ matrix.target }}
ci_test_coverage:
runs-on: ubuntu-latest
runs-on: ubuntu-26.04
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -197,7 +197,7 @@ jobs:
- name: Build
run: cmake --build build --target ci_test_coverage
- name: Archive coverage report
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
with:
name: code-coverage-report
path: ${{ github.workspace }}/build/html
@@ -244,7 +244,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: CXX=g++-${{ matrix.compiler }} cmake -S . -B build -DJSON_CI=On
- name: Build
@@ -262,7 +262,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
@@ -279,7 +279,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Disable filesystem support (std::filesystem is unusable) for clang 7 / 8 / 9 / 10
run: echo "JSON_FORCED_GLOBAL_COMPILE_OPTIONS=-DJSON_HAS_FILESYSTEM=0;-DJSON_HAS_EXPERIMENTAL_FILESYSTEM=0" >> "$GITHUB_ENV"
if: ${{ matrix.compiler == '7' || matrix.compiler == '8' || matrix.compiler == '9' || matrix.compiler == '10' }}
@@ -299,7 +299,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
@@ -319,7 +319,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build with libc++
@@ -346,7 +346,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
@@ -366,7 +366,7 @@ jobs:
# import-std support. Its opt-in token is CMake-version-specific, so pin
# CMake to the version whose token is set in tests/module_cpp20/CMakeLists.txt.
- name: Get pinned CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
with:
cmakeVersion: 4.3.4
# Clang: the std library module is provided by libc++ (the image's libstdc++
@@ -392,7 +392,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
@@ -409,7 +409,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
@@ -423,17 +423,17 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DJSON_CI=On
- name: Build
run: cmake --build build --target ci_nvhpc
ci_emscripten:
runs-on: ubuntu-latest
runs-on: ubuntu-26.04
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -443,20 +443,20 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Run CMake
run: cmake -S . -B build -DCMAKE_TOOLCHAIN_FILE=$EMSDK/upstream/emscripten/cmake/Modules/Platform/Emscripten.cmake -GNinja
- name: Build
run: cmake --build build
ci_test_documentation:
runs-on: ubuntu-latest
runs-on: ubuntu-26.04
strategy:
matrix:
target: [ci_test_examples, ci_test_build_documentation, ci_test_documentation_mermaid]
steps:
- name: Harden Runner
uses: step-security/harden-runner@351661ca32ac09a36dc5ee2d536e3128f2a3c8ed # v2.22.0
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
with:
egress-policy: audit
@@ -465,7 +465,7 @@ jobs:
persist-credentials: false
# the git-revision-date-localized plugin needs the history; a shallow clone makes the strict build fail
fetch-depth: ${{ matrix.target == 'ci_test_build_documentation' && '0' || '1' }}
- uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
- uses: actions/setup-node@949feb2413d6458794dcd2491c4babbbce0c15c1 # v7.1.0
if: matrix.target == 'ci_test_documentation_mermaid'
with:
node-version: 24
@@ -484,7 +484,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Check that the job runs natively on arm64
run: uname -m && test "$(uname -m)" = aarch64
- name: Run CMake
.github/workflows/windows.yml
+12 -10
View File
@@ -90,7 +90,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
- name: Set extra CXX_FLAGS for latest std_version
# /wd5285 silences C5285 emitted by the bundled third-party doctest.h, which
# specializes std::tuple (newly diagnosed by the VS2026 v145 toolset)
@@ -166,19 +166,21 @@ jobs:
# link, but the binaries clang 11.0.1 and clang 18.1.8 then produce crash
# before doctest prints its first line - 39 of 102 tests on clang 18.
# Keep the objects small by splitting the test files instead.
# Objects with more than 65535 sections fail to link with "relocation
# truncated to fit: IMAGE_REL_AMD64_REL32 against `.rdata'": the MinGW
# linker stores the section an associative COMDAT section belongs to in
# 16 bits (x_associated in binutils' include/coff/internal.h), so it
# discards the jump tables of inline functions together with the wrong
# function. Each basic_json specialization a test file instantiates adds
# many sections, so test a second one in a file of its own.
# The tests link with LLD: GNU ld fails on objects with more than 32767
# sections with "relocation truncated to fit: IMAGE_REL_AMD64_REL32
# against `.rdata'", as it stores the section an associative COMDAT
# section belongs to in 16 bits (x_associated in binutils'
# include/coff/internal.h) and so discards the jump tables of inline
# functions together with the wrong function. Each basic_json
# specialization and input type a test file instantiates adds many
# sections, so unit-msgpack.cpp and unit-regression2.cpp kept crossing
# that limit as the library grew.
- name: Run CMake
run: cmake -S . -B build ^
-DCMAKE_CXX_COMPILER="C:/Program Files/LLVM/bin/clang++.exe" ^
-DCMAKE_CXX_FLAGS="--target=x86_64-w64-mingw32 -stdlib=libstdc++ -pthread" ^
-DCMAKE_CXX_FLAGS_DEBUG="-g0" ^
-DCMAKE_EXE_LINKER_FLAGS="-lwinpthread" ^
-DCMAKE_EXE_LINKER_FLAGS="-fuse-ld=lld -lwinpthread" ^
-G"MinGW Makefiles" ^
-DCMAKE_BUILD_TYPE=Debug ^
-DJSON_BuildTests=On
@@ -214,7 +216,7 @@ jobs:
# import-std support. Its opt-in token is CMake-version-specific, so pin
# CMake to the version whose token is set in tests/module_cpp20/CMakeLists.txt.
- name: Get pinned CMake and ninja
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
with:
cmakeVersion: 4.3.4
# CMAKE_CXX_FLAGS replaces CMake's MSVC defaults (which include /EHsc), and
.inferconfig
+4
View File
@@ -1,6 +1,7 @@
{
"_comment": "Used by the ci_infer CMake target (#5715 item 4b). fail-on-issue makes CI fail on Infer findings; disable-issue-type is a type-level baseline for the ~174 pre-existing findings (all PULSE_UNNECESSARY_COPY*/PULSE_RESOURCE_LEAK/PULSE_CONST_REFABLE, mostly in test code) triaged in run https://github.com/nlohmann/json/actions/runs/35829411620 on commit 1054b2097, so CI fails only on a NEW issue type. Remove an entry here once its findings have been fixed or explicitly accepted.",
"_comment_pulse": "Pulse stops exploring paths after pulse-max-disjuncts (default 20). With the default, basic_json::replace_value() (destroy + assert_invariant) exceeds the limit, Pulse loses the stored type, and reports false NULLPTR_DEREFERENCE findings for get_ptr() results in tests/src/unit-pointer_access.cpp.",
"_comment_view": "Infer's model of std::unique_ptr mixes up values that are returned by value and own one: basic_json_document (parse() results) and the `built` values of the build() helper in tests/src/unit-json_view_builder.cpp. It reports USE_AFTER_DELETE for one of them after the destructor of an unrelated object (e.g. ~built() on line 345 invalidating `shallow` on line 350 of that file, or two documents parsed in one lambda in tests/src/unit-json_view_dump.cpp). AddressSanitizer and Valgrind are clean on the same tests, so reports for the json_view test files are excluded; findings reported in the library headers are still reported.",
"pulse-max-disjuncts": 40,
"fail-on-issue": true,
"disable-issue-type": [
@@ -10,5 +11,8 @@
"PULSE_UNNECESSARY_COPY_OPTIONAL",
"PULSE_RESOURCE_LEAK",
"PULSE_CONST_REFABLE"
],
"report-block-list-path-regex": [
"tests/src/unit-json_view.*\\.cpp"
]
}
BUILD.bazel
+1
View File
@@ -37,6 +37,7 @@ cc_library(
"include/nlohmann/detail/input/parser.hpp",
"include/nlohmann/detail/input/position_t.hpp",
"include/nlohmann/detail/input/pow5_table.hpp",
"include/nlohmann/detail/input/simd_scan.hpp",
"include/nlohmann/detail/input/string_scan.hpp",
"include/nlohmann/detail/iterators/internal_iterator.hpp",
"include/nlohmann/detail/iterators/iter_impl.hpp",
cmake/ci.cmake
+11 -4
View File
@@ -361,10 +361,10 @@ add_custom_target(ci_test_coverage
COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_coverage32
COMMAND cd ${PROJECT_BINARY_DIR}/build_coverage32 && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
COMMAND ${LCOV_TOOL} --directory . --capture --output-file json.info --rc branch_coverage=1 --rc geninfo_unexecuted_blocks=1 --ignore-errors mismatch --ignore-errors unused
COMMAND ${LCOV_TOOL} -e json.info ${SRC_FILES} --output-file json.info.filtered --rc branch_coverage=1 --ignore-errors unused
COMMAND ${LCOV_TOOL} --directory . --capture --output-file json.info --rc branch_coverage=1 --rc geninfo_unexecuted_blocks=1 --ignore-errors mismatch --ignore-errors unused --ignore-errors inconsistent
COMMAND ${LCOV_TOOL} -e json.info ${SRC_FILES} --output-file json.info.filtered --rc branch_coverage=1 --ignore-errors unused --ignore-errors inconsistent
COMMAND ${CMAKE_SOURCE_DIR}/tests/thirdparty/imapdl/filterbr.py json.info.filtered > json.info.filtered.noexcept
COMMAND ${GENHTML_TOOL} --title "JSON for Modern C++" --legend --demangle-cpp --output-directory html --show-details --branch-coverage json.info.filtered.noexcept
COMMAND ${GENHTML_TOOL} --title "JSON for Modern C++" --legend --demangle-cpp --output-directory html --show-details --branch-coverage --ignore-errors inconsistent json.info.filtered.noexcept
COMMENT "Compile and test with coverage"
)
@@ -488,6 +488,13 @@ add_custom_target(ci_clang_analyze
# Check code with Cppcheck.
###############################################################################
# default_defines.hpp expands the Hedley macros to the compiler's feature-test operators, which Cppcheck does not know.
# Since Cppcheck 2.20, it rejects their invocations in #if conditions instead of evaluating them as 0.
file(WRITE ${CMAKE_BINARY_DIR}/cppcheck_feature_tests.hpp "")
foreach(OPERATOR __has_attribute __has_builtin __has_cpp_attribute __has_declspec_attribute __has_extension __has_feature __has_include __has_warning)
file(APPEND ${CMAKE_BINARY_DIR}/cppcheck_feature_tests.hpp "#define ${OPERATOR}(x) 0\n")
endforeach()
add_custom_target(ci_cppcheck
COMMAND mkdir -p cppcheck
COMMAND clang -dM -E -x c++ -std=c++11 ${CMAKE_SOURCE_DIR}/include/nlohmann/thirdparty/hedley/hedley.hpp > default_defines.hpp 2> /dev/null
@@ -496,7 +503,7 @@ add_custom_target(ci_cppcheck
COMMAND venv_cppcheck/bin/cppcheck --enable=warning --check-level=exhaustive --inline-suppr --inconclusive --force
--std=c++11 ${PROJECT_SOURCE_DIR}/include/nlohmann/json.hpp -I ${CMAKE_SOURCE_DIR}/include
--error-exitcode=1 --relative-paths=${PROJECT_SOURCE_DIR} -j ${N} --include=default_defines.hpp
--cppcheck-build-dir=cppcheck
--include=${CMAKE_BINARY_DIR}/cppcheck_feature_tests.hpp --cppcheck-build-dir=cppcheck
-UJSON_CATCH_USER -UJSON_TRY_USER -UJSON_ASSERT -UJSON_INTERNAL_CATCH -UJSON_THROW
-DJSON_HAS_CPP_11 -UJSON_HAS_CPP_14 -UJSON_HAS_CPP_17 -UJSON_HAS_CPP_20 -UJSON_HAS_THREE_WAY_COMPARISON
COMMENT "Check code with Cppcheck"
cmake/requirements/requirements-cppcheck.txt
+1 -1
View File
@@ -1 +1 @@
cppcheck==1.5.1
cppcheck==1.5.3
docs/mkdocs/docs/api/basic_json/accept.md
+8
View File
@@ -132,6 +132,10 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
- [operator>>](../operator_gtgt.md) - deserialize from stream
- [`JSON_STRICT_NUL_HANDLING`](../macros/json_strict_nul_handling.md) - opt in to rejecting a NUL byte in the input
instead of treating it as end of input
- [`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md) - read a `std::istream` one character
at a time
- [`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md) - read a `FILE*` with the locking stdio
functions
## Version history
@@ -143,6 +147,10 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
- `JSON_STRICT_NUL_HANDLING` added in version 3.13.0 to optionally reject a NUL byte in the input instead of treating
it as end of input; planned to become the default in version 4.0.0.
- Parsing from an `std::istream` scans the characters in its stream buffer in bulk in version 3.13.0
([`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md)).
- Parsing from a `FILE*` locks the file once instead of once per character in version 3.13.0
([`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md)).
!!! warning "Deprecation"
docs/mkdocs/docs/api/basic_json/array_t.md
+1 -1
View File
@@ -27,7 +27,7 @@ To store objects in C++, a type is defined by the template parameters explained
### Default type
With the default values for `ArrayType` (`std::vector`) and `AllocatorType` (`std::allocator`), the default value for
With the default values for `ArrayType` (`std::vector`) and `AllocatorType` (`std::allocator`), the default type for
`array_t` is:
```cpp
docs/mkdocs/docs/api/basic_json/basic_json.md
+11 -1
View File
@@ -68,6 +68,14 @@ basic_json(basic_json&& other) noexcept;
`std::unordered_map`, `std::multimap`, and `std::unordered_multimap` with a `key_type` compatible to `string_t`
and a `value_type` from which a `basic_json` value can be constructed.
- **strings**: `string_t`, string literals, and all compatible string containers can be used.
!!! note "Rvalue containers are moved from"
If `val` is an rvalue of a compatible array-like or object-like container other than `array_t`/`object_t`
(e.g., `json j = std::move(vec);` or `json j(std::vector<std::string>{...});`), the elements are moved into
the JSON value instead of copied. Afterwards, the elements of the source container are in a valid but
unspecified state (**moved-from**). Keys of associative containers are `const` and therefore still copied.
Lvalues and `const` rvalues are copied, and the source is left unchanged.
- **numbers**: [`number_integer_t`](number_integer_t.md), [`number_unsigned_t`](number_unsigned_t.md),
[`number_float_t`](number_float_t.md), and all convertible number types such as `int`, `size_t`, `int64_t`, `float`
or `double` can be used.
@@ -236,7 +244,9 @@ basic_json(basic_json&& other) noexcept;
2. No-throw guarantee: this constructor never throws exceptions.
3. Depends on the called constructor. For types directly supported by the library (i.e., all types for which no
`to_json()` function was provided), a strong guarantee holds: if an exception is thrown, there are no changes to any
JSON value.
JSON value. **Exception:** when `val` is an rvalue array-like or object-like container, its elements are moved one
by one; if an exception is thrown in the middle of the conversion (e.g., an allocation failure), the JSON value is
unchanged, but the source container may be left partially moved-from.
4. Depends on the called constructor. For types directly supported by the library (i.e., all types for which no
`to_json()` function was provided), a strong guarantee holds: if an exception is thrown, there are no changes to any
JSON value.
docs/mkdocs/docs/api/basic_json/boolean_t.md
+1 -1
View File
@@ -23,7 +23,7 @@ To store boolean values in C++, a type is defined by the template parameter `Bo
### Default type
With the default values for `BooleanType` (`#!cpp bool`), the default value for `boolean_t` is `#!cpp bool`.
With the default values for `BooleanType` (`#!cpp bool`), the default type for `boolean_t` is `#!cpp bool`.
### Storage
docs/mkdocs/docs/api/basic_json/find.md
+2 -1
View File
@@ -93,7 +93,8 @@ Logarithmic in the size of the JSON object.
- [count](count.md) returns the number of occurrences of a key
- [contains](contains.md) checks whether a key exists
- [basic_json_view::find](../basic_json_view/find.md) - the same lookup on a zero-copy view
- [basic_json_view::find](../basic_json_view/find.md) - the same lookup on a zero-copy view (a duplicate key resolves
to the first member, whereas `parse()` keeps the last)
## Version history
docs/mkdocs/docs/api/basic_json/front.md
+2 -1
View File
@@ -51,7 +51,8 @@ Constant.
## See also
- [back](back.md) to access the last element
- [basic_json_view::front](../basic_json_view/front.md) - the same access on a zero-copy view
- [basic_json_view::front](../basic_json_view/front.md) - the same access on a zero-copy view (document order, not
sorted; duplicate keys are visited)
## Version history
docs/mkdocs/docs/api/basic_json/is_number_unsigned.md
+3
View File
@@ -6,6 +6,9 @@ constexpr bool is_number_unsigned() const noexcept;
This function returns `#!cpp true` if and only if the JSON value is an unsigned integer number. This excludes
floating-point and signed integer values.
If [`number_unsigned_t`](number_unsigned_t.md) is the same type as [`number_integer_t`](number_integer_t.md), every
integer is stored as `number_integer_t`, and this function always returns `#!cpp false`.
## Return value
docs/mkdocs/docs/api/basic_json/items.md
+1 -1
View File
@@ -100,7 +100,7 @@ When iterating over an array, `key()` will return the index of the element as st
- [begin](begin.md) returns an iterator to the first element
- [end](end.md) returns an iterator to one past the last element
- [basic_json_view::items](../basic_json_view/items.md) - the same range on a zero-copy view (`#!cpp const auto`,
not `#!cpp const auto&`: items are produced on the fly)
not `#!cpp const auto&`: items are produced on the fly; document order, not sorted; duplicate keys are visited)
## Version history
docs/mkdocs/docs/api/basic_json/number_float_t.md
+4 -3
View File
@@ -35,7 +35,7 @@ type to use.
### Default type
With the default values for `NumberFloatType` (`double`), the default value for `number_float_t` is `#!cpp double`.
With the default values for `NumberFloatType` (`double`), the default type for `number_float_t` is `#!cpp double`.
### Default behavior
@@ -52,8 +52,9 @@ With the default values for `NumberFloatType` (`double`), the default value for
> interoperability can be achieved by implementations that expect no more precision or range than these provide, in the
> sense that implementations will approximate JSON numbers within the expected precision.
This implementation does exactly follow this approach, as it uses double precision floating-point numbers. Note that
numbers smaller than `-1.79769313486232e+308` or greater than `1.79769313486232e+308` are rejected during parsing with
This implementation does exactly follow this approach, as it uses double precision floating-point numbers by default.
Note that with the default `double`, numbers smaller than `-1.79769313486232e+308` or greater than
`1.79769313486232e+308` are rejected during parsing with
[`out_of_range.406`](../../home/exceptions.md#jsonexceptionout_of_range406). Non-finite values (NaN and infinity) can
only be stored by assigning them directly and are serialized to `null`.
docs/mkdocs/docs/api/basic_json/number_integer_t.md
+1 -1
View File
@@ -31,7 +31,7 @@ to use.
### Default type
With the default values for `NumberIntegerType` (`std::int64_t`), the default value for `number_integer_t` is
With the default values for `NumberIntegerType` (`std::int64_t`), the default type for `number_integer_t` is
`#!cpp std::int64_t`.
### Default behavior
docs/mkdocs/docs/api/basic_json/number_unsigned_t.md
+4 -2
View File
@@ -25,14 +25,15 @@ the type to use.
`NumberUnsignedType`
: the type to store unsigned integers. It must be an **unsigned integral** type (`#!cpp std::is_integral`) with a
`#!cpp std::numeric_limits` specialization, and it must be able to represent the absolute value of every
[`number_integer_t`](number_integer_t.md) value. See
[`number_integer_t`](number_integer_t.md) value. Alternatively, it can be the same type as
[`number_integer_t`](number_integer_t.md); then every integer is stored as `number_integer_t`. See
[Template Parameter Requirements](../../features/types/template_parameters.md#numberintegertype-and-numberunsignedtype).
## Notes
### Default type
With the default values for `NumberUnsignedType` (`std::uint64_t`), the default value for `number_unsigned_t` is
With the default values for `NumberUnsignedType` (`std::uint64_t`), the default type for `number_unsigned_t` is
`#!cpp std::uint64_t`.
### Default behavior
@@ -89,3 +90,4 @@ Integer number values are stored directly inside a `basic_json` type.
## Version history
- Added in version 2.0.0.
- Can be the same type as `number_integer_t` since version 3.13.0.
docs/mkdocs/docs/api/basic_json/object_t.md
+1 -1
View File
@@ -36,7 +36,7 @@ To store objects in C++, a type is defined by the template parameters described
### Default type
With the default values for `ObjectType` (`std::map`), `StringType` (`std::string`), and `AllocatorType`
(`std::allocator`), the default value for `object_t` is:
(`std::allocator`), the default type for `object_t` is:
```cpp
// until C++14
docs/mkdocs/docs/api/basic_json/operator[].md
+3 -2
View File
@@ -275,8 +275,9 @@ Strong exception safety: if an exception occurs, the original value stays intact
- documentation on [runtime assertions](../../features/assertions.md)
- see [`at`](at.md) for access by reference with range checking
- see [`value`](value.md) for access with default value
- [basic_json_view::operator[]](../basic_json_view/operator%5B%5D.md) - the same access on a zero-copy view (always
returns a discarded view instead of assuming undefined behavior)
- [basic_json_view::operator[]](../basic_json_view/operator%5B%5D.md) - the same access on a zero-copy view (a duplicate
key resolves to the first member, whereas `parse()` keeps the last; a missing key gives a discarded view instead of
undefined behavior)
## Version history
docs/mkdocs/docs/api/basic_json/parse.md
+19
View File
@@ -112,6 +112,16 @@ By default, a `'\0'` (NUL) byte anywhere in the input is treated as end of input
outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-bytes-in-the-input) for details and the
[`JSON_STRICT_NUL_HANDLING`](../macros/json_strict_nul_handling.md) macro to opt into rejecting it instead.
!!! tip "Performance"
Contiguous inputs (strings, string views, vectors, arrays, pointer ranges) are the fastest to parse. A
`#!cpp std::istream` comes close: the parser scans the characters its stream buffer holds in bulk, without reading
ahead, so the stream is left exactly where it would be after reading one character at a time. A `#!cpp FILE*` is
read one character at a time, but the file is locked only once, so other threads that use the same `FILE` object
wait until parsing is done. See [input sources and performance](../../features/parsing/index.md#input-sources-and-performance),
[`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md), and
[`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md).
## Examples
??? example "Example: (1) parse from a character array"
@@ -247,6 +257,10 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
- [operator>>](../operator_gtgt.md) - deserialize from stream
- [`JSON_STRICT_NUL_HANDLING`](../macros/json_strict_nul_handling.md) - opt in to rejecting a NUL byte in the input
instead of treating it as end of input
- [`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md) - read a `std::istream` one character
at a time
- [`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md) - read a `FILE*` with the locking stdio
functions
## Version history
@@ -261,6 +275,11 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
it as end of input; planned to become the default in version 4.0.0.
- Extended empty-input detection to also cover an `std::istream` without a stream buffer, and fixed a crash
(`std::terminate`) when parsing from an `std::istream` with `eofbit` in its exception mask, in version 3.13.0.
- Parsing from an `std::istream` scans the characters in its stream buffer in bulk in version 3.13.0
([`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md) restores reading one character at a
time).
- Parsing from a `FILE*` locks the file once instead of once per character in version 3.13.0
([`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md) restores `std::fgetc`).
!!! warning "Deprecation"
docs/mkdocs/docs/api/basic_json/sax_parse.md
+12
View File
@@ -116,6 +116,10 @@ consumer `sax` has a super-linear complexity.
A UTF-8 byte order mark is silently ignored.
When reading from a `#!c FILE*`, the file is locked while it is parsed. The lock is recursive, so the SAX handler may
use the same file with stdio functions, but it must not wait for another thread that uses the same `FILE` object; see
[`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md).
## Examples
??? example
@@ -137,6 +141,10 @@ A UTF-8 byte order mark is silently ignored.
- [parse](parse.md) - deserialize from a compatible input
- [accept](accept.md) - check if the input is valid JSON
- [`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md) - read a `std::istream` one character
at a time
- [`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md) - read a `FILE*` with the locking stdio
functions
## Version history
@@ -148,6 +156,10 @@ A UTF-8 byte order mark is silently ignored.
- Extended overload (2) to accept heterogeneous iterator+sentinel pairs (C++20 ranges support) in version 3.13.0.
- `JSON_PRECISE_STREAM_POSITION` added in version 3.13.0 to optionally leave a `#!cpp std::istream` positioned right
after the parsed value when `strict` is `#!cpp false`.
- Parsing from an `std::istream` scans the characters in its stream buffer in bulk in version 3.13.0
([`JSON_DISABLE_STREAM_BULK_SCAN`](../macros/json_disable_stream_bulk_scan.md)).
- Parsing from a `FILE*` locks the file once instead of once per character in version 3.13.0
([`JSON_DISABLE_UNLOCKED_FILE_IO`](../macros/json_disable_unlocked_file_io.md)).
!!! warning "Deprecation"
docs/mkdocs/docs/api/basic_json/string_t.md
+1 -1
View File
@@ -32,7 +32,7 @@ JSON class into byte-sized characters during deserialization.
### Default type
With the default values for `StringType` (`std::string`), the default value for `string_t` is `#!cpp std::string`.
With the default values for `StringType` (`std::string`), the default type for `string_t` is `#!cpp std::string`.
### Encoding
docs/mkdocs/docs/api/basic_json/to_bjdata.md
+3 -1
View File
@@ -123,4 +123,6 @@ Linear in the size of the JSON value `j`.
that is not valid UTF-8 unchanged, as before; `strict` (the default if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.
- Throws `type_error.321` for a discarded value since version 3.13.0; previously, a discarded value nested in an
array or object was silently skipped, producing invalid BJData.
array or object was silently skipped, producing invalid BJData.
- Writes unsigned integers wider than 64 bits as high-precision numbers since version 3.13.0; previously, they were
silently truncated to 64 bits.
docs/mkdocs/docs/api/basic_json/to_bon8.md
+3 -2
View File
@@ -37,8 +37,9 @@ With (2), the bytes written before the exception remain in the output adapter.
## Exceptions
- Throws [out_of_range.407](../../home/exceptions.md#jsonexceptionout_of_range407) if `j` contains an unsigned integer
above 9223372036854775807, which BON8 cannot represent
- Throws [out_of_range.407](../../home/exceptions.md#jsonexceptionout_of_range407) if `j` contains an integer outside
the range of int64 (an unsigned integer above 9223372036854775807, or, with a number type wider than 64 bits, any
integer beyond int64), which BON8 cannot represent
- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if `j` contains a string that is not
valid UTF-8
- Throws [type_error.321](../../home/exceptions.md#jsonexceptiontype_error321) if `j` or a value nested in it is
docs/mkdocs/docs/api/basic_json/to_bson.md
+6
View File
@@ -47,6 +47,10 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [`type_error.317`](../../home/exceptions.md#jsonexceptiontype_error317) if the top-level type of the JSON value
is not an object; example: `"to serialize to BSON, top-level type must be object, but is string"`
- Throws [`out_of_range.407`](../../home/exceptions.md#jsonexceptionout_of_range407) if `j` contains a signed integer
outside the range of int64 or an unsigned integer outside the range of uint64, which is only possible with a number
type wider than 64 bits; example:
`"integer number 9223372036854775808 cannot be represented by BSON as it does not fit int64"`
- Throws [`out_of_range.409`](../../home/exceptions.md#jsonexceptionout_of_range409) if a key in the JSON object contains
a null byte (code point U+0000); example: `"BSON key cannot contain code point U+0000 (at byte 2)"`
- Throws [`out_of_range.412`](../../home/exceptions.md#jsonexceptionout_of_range412) if the length of a document, array,
@@ -119,3 +123,5 @@ pass before anything is written.
that is not valid UTF-8 unchanged, as before; `strict` (the default if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316` before anything
is written.
- Throws `out_of_range.407` for integers that do not fit 64 bits since version 3.13.0; previously, integers of a
number type wider than 64 bits were silently truncated.
docs/mkdocs/docs/api/basic_json/to_cbor.md
+5
View File
@@ -46,6 +46,9 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
## Exceptions
- Throws [`out_of_range.407`](../../home/exceptions.md#jsonexceptionout_of_range407) if `j` contains an integer
outside [-2^64, 2^64-1], which is only possible with a number type wider than 64 bits; example:
`"integer number 18446744073709551616 cannot be represented by CBOR as it does not fit [-2^64, 2^64-1]"`
- Throws [type_error.316](../../home/exceptions.md#jsonexceptiontype_error316) if a string or object key in `j` is
not valid UTF-8 and `error_handler` is `strict` (the default only if
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled)
@@ -90,3 +93,5 @@ Linear in the size of the JSON value `j`.
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.
- Throws `type_error.321` for a discarded value since version 3.13.0; previously, a discarded value nested in an
array or object was silently skipped, producing invalid CBOR.
- Throws `out_of_range.407` for integers that do not fit 64 bits since version 3.13.0; previously, integers of a
number type wider than 64 bits were silently truncated.
docs/mkdocs/docs/api/basic_json/to_msgpack.md
+5
View File
@@ -46,6 +46,9 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
## Exceptions
- Throws [`out_of_range.407`](../../home/exceptions.md#jsonexceptionout_of_range407) if `j` contains an integer
outside [-2^63, 2^64-1], which is only possible with a number type wider than 64 bits; example:
`"integer number 18446744073709551616 cannot be represented by MessagePack as it does not fit [-2^63, 2^64-1]"`
- Throws [`out_of_range.412`](../../home/exceptions.md#jsonexceptionout_of_range412) if the length of a string, binary
value, array, or object exceeds 4294967295, the maximum MessagePack can store; example:
`"MessagePack length 4294967296 exceeds maximum of 4294967295"`
@@ -112,3 +115,5 @@ Linear in the size of the JSON value `j`.
`number_unsigned_t`.
- Throws `type_error.321` for a discarded value since version 3.13.0; previously, a discarded value nested in an
array or object was silently skipped, producing invalid MessagePack.
- Throws `out_of_range.407` for integers that do not fit 64 bits since version 3.13.0; previously, integers of a
number type wider than 64 bits were silently truncated.
docs/mkdocs/docs/api/basic_json_document/erase.md
+12 -11
View File
@@ -18,10 +18,10 @@ has `erase`; calling it on a read-only `basic_json_document` fails to compile (`
1. Removes every member of `object` whose key is `key` (see [Notes](#notes) on duplicate keys) and returns how many
were removed; `#!cpp 0` if `object` has no member with this key.
2. Removes the element at index `idx` of `array`, which must already exist (`#!cpp idx < array.size()`).
3. Removes the value the JSON pointer `ptr` refers to, relative to [`root()`](root.md), and returns how many values
were removed: the *parent* of the target must already exist, and the target itself is removed as in 1. (an object
member; `#!cpp 0` or more) or 2. (an array element; always `#!cpp 1`). `ptr` must not be empty -- [`root()`](root.md)
itself cannot be erased.
3. Removes the value the JSON pointer `ptr` refers to, relative to [`root()`](root.md). `ptr` must not be empty
([`root()`](root.md) itself cannot be erased), and the *parent* of the target must already exist. The target is
removed as in 1. if the parent is an object (returns the number of removed members, `#!cpp 0` or more) and as in 2.
if it is an array (always returns `#!cpp 1`).
## Template parameters
@@ -69,10 +69,10 @@ has `erase`; calling it on a read-only `basic_json_document` fails to compile (`
[`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) (an empty token); otherwise (an
object, or a primitive value the pointer's parent resolves to) throws what 1. throws.
Every overload also throws [`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view
does not belong to this document") if `object`/`array` is a [discarded](../basic_json_view/is_discarded.md) view or a
view of a *different* document (overloads 1-2 only; overload 3 always starts from this document's own
[`root()`](root.md)).
Overloads 1. and 2. also throw [`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202)
("view does not belong to this document") if `object`/`array` is a [discarded](../basic_json_view/is_discarded.md)
view or a view of a *different* document. Overload 3. never throws `invalid_iterator.202`: it takes no view, and it
always starts from this document's own [`root()`](root.md).
## Complexity
@@ -92,9 +92,10 @@ view of a *different* document (overloads 1-2 only; overload 3 always starts fro
Like [`set`](set.md) and [`push_back`](push_back.md), `erase` never moves an element's *value*: a view still
referring to a removed member or element keeps showing what it last held (see [Edits](index.md#edits)) -- it just no
longer appears when `array`/`object` is read, dumped, or iterated. Removing an element of `array` (2.) does shift the
*links* to the elements after it, the same way `insert`, `set`, or `push_back` on the same array would; any iterator
already taken over `array`/`object` is invalidated by an erase, since it was walking the old layout.
longer appears when `array`/`object` is read, dumped, or iterated. What does change is the container's sequence of
*links* to its elements: removing an element of `array` (2.) shifts the links to the elements after it by one, as
[`insert`](insert.md) does in the other direction. *Every* iterator already taken over `array`/`object` is invalidated
by an erase, not only those at or after the removed element, since the container may now use a different sequence.
## Examples
docs/mkdocs/docs/api/basic_json_document/load.md
+23 -20
View File
@@ -110,17 +110,30 @@ enum class image_check
How thoroughly `load()` validates `image` before trusting it.
| value | checks | guarantees |
|----------|--------------------------------------------------------------------------------------------------------------|------------|
| `full` | everything the parser itself guarantees: structure and bounds; that every string is valid UTF-8 (and, for a string still in the source text, that it contains no quote, backslash, or control character); and that every number token is well-formed and matches the value stored for it; strings and float tokens may share a range only if the ranges are identical (as nodes that share a value do), and never overlap otherwise | reading and serializing a checked image is safe and always produces valid JSON, exactly as for a parsed document |
| `bounds` | structure and bounds only -- that every offset and count in the node index stays inside the image | reading and serializing stay memory-safe, but a crafted image can hold strings that are not valid UTF-8 or that serialize to invalid JSON ([`dump()`](../basic_json_view/dump.md) writes them unchanged or throws [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316)), and numbers whose values differ from their text |
| `none` | nothing | images from a trusted source only -- reading a damaged image is undefined behavior |
`full` (the default)
: Checks everything the parser itself guarantees: structure and bounds; that every string is valid UTF-8 (and, for a
string still in the source text, that it contains no quote, backslash, or control character); and that every number
token is well-formed and matches the value stored for it. Strings and float tokens may share a range only if the
ranges are identical (as nodes that share a value do), and never overlap otherwise. Reading and serializing a
checked image is safe and always produces valid JSON, exactly as for a parsed document. This is the right choice for
an image from anything you do not fully control -- a file, a cache shared with other processes, a peer on the
network.
`full` is the default and the right choice for an image from anything you do not fully control -- a file, a cache
shared with other processes, a peer on the network. `bounds` skips scanning the text and the decoded strings, so it
fits a cache your own process just wrote and reads straight back, where damage would mean a bug or a hardware fault
rather than adversarial input; it still cannot crash or read out of bounds. `none` skips validation entirely and
should only be used for an image you trust as much as your own memory.
`bounds`
: Checks structure and bounds only: that every offset and count in the node index stays inside the image. So
`load()`, [`root()`](root.md), element access, and [`materialize()`](../basic_json_view/materialize.md) can never
read outside the image, even on a damaged one. It does *not* guarantee that the image describes valid JSON: a
string that a `full` check would have rejected can make [`dump()`](../basic_json_view/dump.md) write invalid UTF-8
or invalid JSON, or throw [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316), and a number can
read back with a value that does not match how it is spelled. An [editable document](../json_editable_document.md)
does not take such a string over: [`set`](set.md), [`push_back`](push_back.md) and [`insert`](insert.md) throw
`type_error.316` when they copy it from a view of the loaded document, and leave the editable document unchanged.
`bounds` skips scanning the text and the decoded strings, so it fits a cache your own process just wrote and reads
straight back, where damage would mean a bug or a hardware fault rather than adversarial input.
`none`
: Checks nothing. Reading a damaged image is undefined behavior, so use it only for an image you trust as much as
your own memory.
**Lifetime.** Overloads 1 and 2 borrow `image`: it must stay alive and byte-for-byte unchanged for as long as the
returned document, and any [view](../basic_json_view/index.md) taken from it, is used -- exactly like a document
@@ -134,16 +147,6 @@ returned document, and any [view](../basic_json_view/index.md) taken from it, is
("unknown format"). Use images to cache a document within one build of the library, or to hand one to another
process running the *same* build on the *same* (little-endian) machine -- not as a long-term storage format.
**What `image_check::bounds` does not guarantee.** A bounds-checked image can never make `load()`,
[`root()`](root.md), element access, or [`materialize()`](../basic_json_view/materialize.md) read outside the image,
so those stay safe on a damaged one. It does *not* guarantee that the image describes valid JSON: a string
that a `full` check would have rejected can make [`dump()`](../basic_json_view/dump.md) write invalid UTF-8 or invalid
JSON, or throw `type_error.316`, and a number can read back with a value that does not match how it is spelled.
Reserve `bounds` for images you already trust to be well-formed, and use it only to skip the extra scan.
An [editable document](../json_editable_document.md) does not take such a string over either:
[`set`](set.md), [`push_back`](push_back.md) and [`insert`](insert.md) throw `type_error.316` when they copy it from
a view of the loaded document, and leave the editable document unchanged.
## Examples
??? example "Caching a document, ownership, and a rejected image"
docs/mkdocs/docs/api/basic_json_view/at.md
+3 -3
View File
@@ -41,7 +41,7 @@ basic_json_view at(const json_pointer& ptr) const;
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
Strong guarantee: there are no changes to the view or the document it refers to.
## Exceptions
@@ -77,8 +77,8 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
1. Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
another, in document order, stopping at the first match. Each comparison first checks the
key's length -- already known from the index, without reading the key bytes -- before comparing its content.
Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
on average.
Objects with 128 or more members get a hash index of their keys while parsing, so that a lookup in them takes
constant time on average.
2. Linear in `idx`: elements are skipped one at a time from the first one, since they are not a fixed size in the
index (unlike `BasicJsonType`'s array, which is random-access).
3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
docs/mkdocs/docs/api/basic_json_view/back.md
+2 -3
View File
@@ -13,7 +13,7 @@ The last element or member value. For a primitive value (number, string, boolean
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
Strong guarantee: there are no changes to the view or the document it refers to.
## Exceptions
@@ -33,8 +33,7 @@ index.
## Notes
Unlike [`BasicJsonType::back()`](../basic_json/back.md), which has undefined behavior for an empty array or object,
`back()` throws `invalid_iterator.214` in that case -- the same way it already does for `#!json null` and for a
discarded view, where `BasicJsonType::back()` also throws.
`back()` throws `invalid_iterator.214` for an empty array, an empty object, a null value, or a discarded view.
## Examples
docs/mkdocs/docs/api/basic_json_view/begin.md
+6 -2
View File
@@ -6,7 +6,7 @@ iterator begin() const noexcept;
Returns an iterator to the first element of an array, or the first member value of an object, in **document order**
-- the order the values appear in the source text, not sorted by key. A primitive value iterates as a range of one
element (itself); `#!json null` and a [discarded](is_discarded.md) view iterate as an empty range.
element (itself), and a `#!json null` value or a [discarded](is_discarded.md) view iterates as an empty range.
## Return value
@@ -23,7 +23,7 @@ Constant.
## Notes
For an object, iteration visits **every** member, including all occurrences of a duplicate key -- unlike
[`operator[]`](operator[].md), [`at`](at.md), [`find`](find.md), [`contains`](contains.md), and [`count`](count.md),
[`operator[]`](operator[].md), [`at`](at.md), [`find`](find.md), and [`contains`](contains.md),
which all resolve to the *first* member with a given key. See the
[Notes on duplicate keys](operator[].md#notes) of `operator[]`.
@@ -31,6 +31,10 @@ Because objects are iterated in document order rather than sorted by key, the or
iterating the [`materialize()`](materialize.md)d `BasicJsonType` value would produce: a `#!cpp basic_json` object
(`std::map`-backed by default) sorts its keys, while a view does not.
An `ordered_json` value also keeps document order, but it keeps only one entry per key: as `parse()` does, it keeps the
*last* value, at the position of the key's *first* occurrence. The view, in contrast, visits every member, including
the duplicates.
## Examples
??? example
docs/mkdocs/docs/api/basic_json_view/contains.md
+4 -3
View File
@@ -35,8 +35,8 @@ No-throw guarantee: this function never throws exceptions.
1. Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after
another, in document order, stopping at the first match. Each comparison first checks the
key's length -- already known from the index, without reading the key bytes -- before comparing its content.
Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
on average.
Objects with 128 or more members get a hash index of their keys while parsing, so that a lookup in them takes
constant time on average.
2. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
that level or the index into the array -- as for [`operator[]`](operator[].md#complexity) and
[`at`](at.md#complexity) with a JSON pointer.
@@ -55,7 +55,8 @@ view.
!!! info "Postconditions"
If `#!cpp v.contains(key)` returns `#!cpp true`, then `#!cpp v[key]` is not [discarded](is_discarded.md). If
If `#!cpp v.contains(key)` returns `#!cpp true`, then `#!cpp v[key]` is not [discarded](is_discarded.md) and
`#!cpp v.at(key)` does not throw. If
`#!cpp v.contains(ptr)` returns `#!cpp true`, then `#!cpp v[ptr]` is not discarded and `#!cpp v.at(ptr)` does not
throw.
docs/mkdocs/docs/api/basic_json_view/count.md
+17 -21
View File
@@ -6,7 +6,8 @@ size_type count(const char* key) const;
size_type count(const string_t& key) const;
```
Returns `#!cpp 1` if the value is an object with a member with key `key`, `#!cpp 0` otherwise.
Returns the number of members with key `key` if the value is an object, `#!cpp 0` otherwise. Members with a repeated
key are all counted.
## Parameters
@@ -15,7 +16,8 @@ Returns `#!cpp 1` if the value is an object with a member with key `key`, `#!cpp
## Return value
`#!cpp 1` if the value is an object and has a member with key `key`, `#!cpp 0` otherwise.
the number of members of the object with key `key` (duplicates included), or `#!cpp 0` if the value is not an object
or has no such member.
## Exception safety
@@ -23,36 +25,30 @@ No-throw guarantee: this function never throws exceptions.
## Complexity
Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after another,
in document order, stopping at the first match. Each comparison first checks the key's length
-- already known from the index, without reading the key bytes -- before comparing its content.
Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time on
average.
Linear in the number of members: unlike the lookup functions, `count()` does not stop at the first match, because it
has to count every member with the key. Members are compared one after another, in document order. Each comparison
first checks the key's length -- already known from the index, without reading the key bytes -- before comparing its
content. The hash index of the keys of objects with 128 or more members does not help here, since every member
is visited.
## Notes
!!! warning "Duplicate keys: the first member wins"
If the source text repeats a key, this resolves to the *first* member with it, not to the last one that
[`materialize()`](materialize.md) and `parse()` keep. See the [Notes on duplicate keys](operator[].md#notes) of
`operator[]` and [Duplicate keys](../../features/json_view.md#duplicate-keys) for the reasons and for how to get
the last value.
This method always returns `#!cpp 0` when the value is not an object -- including a [discarded](is_discarded.md)
view.
Unlike [`BasicJsonType::count()`](../basic_json/count.md), whose return value can in principle exceed `#!cpp 1` for
an `ObjectType` that allows multiple entries per key, `count()` here never does: it is exactly
[`contains()`](contains.md) as `#!cpp 0`/`#!cpp 1`. This holds even if the source text has a duplicate key -- see the
[Notes on duplicate keys](operator[].md#notes) of `operator[]` -- because a `#!cpp count() > 1` result would require
counting every member with a matching key (the lookup functions resolve to the *first* one).
If the source text repeats a key, `count()` returns more than `#!cpp 1` for it, even though the
[materialized](materialize.md) value (like the result of `parse()`) would have only one member with that key. Hence
`#!cpp count(key) > 1` detects duplicate keys. This is unlike the lookup functions
([`operator[]`](operator[].md), [`at`](at.md), [`find`](find.md), [`contains`](contains.md)), which resolve to the
*first* member; see the [Notes on duplicate keys](operator[].md#notes) of `operator[]`.
## Examples
??? example
The example below validates that every transaction of a batch carries a mandatory `amount` field, using
`count()` before deciding whether to materialize a transaction at all.
The example below validates that every transaction of a batch carries exactly one `amount` field, using
`count()` before deciding whether to materialize a transaction at all. It reports a transaction with no `amount`
field and one with a duplicated `amount` field.
```cpp
--8<-- "examples/basic_json_view__count.cpp"
docs/mkdocs/docs/api/basic_json_view/dump.md
+4 -2
View File
@@ -60,11 +60,13 @@ Linear in the size of the output text.
The walk over the subtree is iterative, so the nesting depth it can write is limited by available memory only, not by
the call stack -- as for [`materialize()`](materialize.md).
Strings are escaped by the same rules as [`BasicJsonType::dump`](../basic_json/dump.md). With
`#!cpp numbers == number_format::shortest`, floats are written with the library's shortest round-trip conversion,
Strings are escaped by the same rules as [`BasicJsonType::dump`](../basic_json/dump.md).
With `#!cpp numbers == number_format::shortest`, floats are written with the library's shortest round-trip conversion,
exactly as [`BasicJsonType::dump`](../basic_json/dump.md) would (e.g. `#!cpp 1.5`, `#!cpp 100.0`, `#!cpp 1e+100`), and
integers are copied from the source text -- already canonical in JSON, so this matches their shortest form too --
except that `#!cpp -0` is written as `#!cpp 0`, the way [`BasicJsonType::parse()`](../basic_json/parse.md) reads it.
`#!cpp number_format::source` copies every number exactly as written in the source text instead, with no exception
for `#!cpp -0` -- `#!cpp 1.50`, `#!cpp 1E2`, `#!cpp -0.0`, `#!cpp -0`, or all digits of an integer literal with more
digits than any number type holds (such a literal is itself classified as a float, see
docs/mkdocs/docs/api/basic_json_view/end.md
+2 -3
View File
@@ -5,9 +5,8 @@ iterator end() const noexcept;
```
Returns an iterator to one past the last element of an array, one past the last member value of an object, in
**document order** -- see [`begin()`](begin.md). A primitive value iterates as a range of one element (itself);
`#!json null` and a [discarded](is_discarded.md) view iterate as an empty range, so `#!cpp begin() == end()` for
them.
**document order** -- see [`begin()`](begin.md). A primitive value iterates as a range of one element (itself), and a
`#!json null` value or a [discarded](is_discarded.md) view iterates as an empty range (`#!cpp begin() == end()`).
## Return value
docs/mkdocs/docs/api/basic_json_view/find.md
+2 -2
View File
@@ -28,8 +28,8 @@ No-throw guarantee: this function never throws exceptions.
Linear in the number of members: as for [`ordered_json`](../ordered_json.md), members are compared one after another,
in document order, stopping at the first match. Each comparison first checks the key's length
-- already known from the index, without reading the key bytes -- before comparing its content.
Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time on
average.
Objects with 128 or more members get a hash index of their keys while parsing, so that a lookup in them takes
constant time on average.
## Notes
docs/mkdocs/docs/api/basic_json_view/front.md
+3 -3
View File
@@ -13,7 +13,7 @@ The first element or member value. For a primitive value (number, string, boolea
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
Strong guarantee: there are no changes to the view or the document it refers to.
## Exceptions
@@ -31,8 +31,8 @@ Constant.
## Notes
Unlike [`BasicJsonType::front()`](../basic_json/front.md), which has undefined behavior for an empty array or
object, `front()` throws `invalid_iterator.214` in that case -- the same way it already does for `#!json null` and
for a discarded view, where `BasicJsonType::front()` also throws.
object, `front()` throws `invalid_iterator.214` for an empty array, an empty object, a null value, or a discarded
view.
## Examples
docs/mkdocs/docs/api/basic_json_view/get.md
+10 -7
View File
@@ -10,8 +10,8 @@ Converts the value to `T`.
For the types below, the conversion works directly on the flat index -- no `BasicJsonType` value is built for it:
- `#!cpp bool`
- arithmetic types other than `#!cpp bool` (from a number; from a boolean, as `#!cpp 0`/`#!cpp 1`, exactly as
[`BasicJsonType::get<T>()`](../basic_json/get.md) converts a boolean)
- arithmetic types other than `#!cpp bool` (for a boolean, `#!cpp 0`/`#!cpp 1`, exactly as for
[`BasicJsonType::get<T>()`](../basic_json/get.md))
- `#!cpp std::nullptr_t`
- `#!cpp std::basic_string<char, Traits, Alloc>` (including `string_t`) -- a copy of the string
- [`string_view_t`](index.md#member-types) -- **no copy**: the returned view points into the document's
@@ -19,10 +19,10 @@ For the types below, the conversion works directly on the flat index -- no `Basi
document's own buffer of decoded strings (see [`get_string()`](get_string.md))
- `BasicJsonType` -- equivalent to [`materialize()`](materialize.md)
- `basic_json_view` -- returns `#!cpp *this`
- `#!cpp std::vector<U, A>` -- element by element, each converted with `#!cpp get<U>()`; `#!cpp
- `#!cpp std::vector<U, A>` -- from an array, element by element, each converted with `#!cpp get<U>()`; `#!cpp
std::vector<basic_json_view>` keeps a view of every element instead of a value
- `#!cpp std::map<K, V, C, A>` and `#!cpp std::unordered_map<K, V, H, E, A>`, if `K` is constructible from a `#!cpp
(const char*, std::size_t)` pair -- member by member, each value converted with `#!cpp get<V>()`; with a repeated
(const char*, std::size_t)` pair -- from an object, member by member, each value converted with `#!cpp get<V>()`; with a repeated
key, the *last* value is kept, as [`BasicJsonType::parse()`](../basic_json/parse.md) (and
[`materialize()`](materialize.md)) does; `#!cpp std::map<std::string, basic_json_view>` keeps views of the members
instead of values
@@ -43,7 +43,7 @@ the value, converted to `T`
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
Strong guarantee: there are no changes to the view or the document it refers to.
## Exceptions
@@ -62,6 +62,9 @@ None of the exceptions thrown directly by this function (the first three bullets
[`JSON_DIAGNOSTICS`](../macros/json_diagnostics.md) path: the view has no `BasicJsonType` value to point at. An
exception thrown while converting through `materialize()` (the last bullet) is different: it is thrown by a real
`BasicJsonType` value, so it **does** carry a `JSON_DIAGNOSTICS` path if `BasicJsonType` was built with it enabled.
That path is relative to the root of the view's subtree, because `materialize()` builds only the subtree (with parent
pointers): it is empty if the failing value is the subtree's root itself, and it never is the path within the whole
document.
## Complexity
@@ -73,8 +76,8 @@ exception thrown while converting through `materialize()` (the last bullet) is d
- `#!cpp std::map`/`#!cpp std::unordered_map`: linear in the number of members for walking them, plus the container's
own insertion cost per member (logarithmic for `#!cpp std::map`, amortized constant for `#!cpp
std::unordered_map`), times the complexity of converting one member to the mapped type.
- every other `T`: linear in the size of the subtree (building the `BasicJsonType` value), plus the complexity of
[`BasicJsonType::get<T>()`](../basic_json/get.md) on it.
- every other `T`: the cost of [`materialize()`](materialize.md) and of destroying the `BasicJsonType` value
afterwards, plus that of [`BasicJsonType::get<T>()`](../basic_json/get.md).
## Notes
docs/mkdocs/docs/api/basic_json_view/get_string.md
+7 -2
View File
@@ -15,7 +15,7 @@ had to be decoded once when the document was parsed).
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
Strong guarantee: there are no changes to the view or the document it refers to.
## Exceptions
@@ -37,9 +37,14 @@ hand out a reference to a stored `string_t`. `get_string()` (equivalently, [`get
zero-copy alternative: [`BasicJsonType::get_ref<const string_t&>()`](../basic_json/get_ref.md) is its closest
counterpart, except that it returns a view instead of a reference to a value that must already exist.
`get_string()` borrows the string: nothing is copied, whereas [`get<std::string>()`](get.md) copies it. For a borrowed
document, the returned [`string_view_t`](index.md#member-types) is valid as long as the caller's buffer; for an owned
one, as long as the document.
The returned [`string_view_t`](index.md#member-types) is valid exactly as long as the view that produced it -- see the
[validity rules](index.md) of `basic_json_view` -- and, for a string with no escapes, for as long as the document's
source text.
source text, which for a borrowed document must remain valid **and unmodified** for as long as the document exists,
since floating-point values and unescaped strings are read from the source lazily.
## Examples
docs/mkdocs/docs/api/basic_json_view/get_to.md
+23 -8
View File
@@ -5,12 +5,15 @@ template<typename T>
T& get_to(T& v) const;
```
Converts the value to `T` and assigns it to `v`. Equivalent to
Converts the value to `T` and stores it in `v`, in one of two ways:
```cpp
v = get<T>();
return v;
```
- For the types that [`get<T>()`](get.md) converts directly -- arithmetic types, `#!cpp bool`,
`#!cpp std::nullptr_t`, [`string_view_t`](index.md#member-types), `#!cpp std::basic_string`, `BasicJsonType`,
`basic_json_view`, `#!cpp std::vector`, and `#!cpp std::map`/`#!cpp std::unordered_map` with string keys -- `v` is
assigned: `#!cpp v = get<T>()`.
- For every other type, the subtree is built into a `BasicJsonType` value and `#!cpp materialize().get_to(v)` is
called, i.e. `from_json()` is invoked with the existing `v`, exactly as
[`BasicJsonType::get_to()`](../basic_json/get_to.md) does.
## Template parameters
@@ -28,15 +31,27 @@ return v;
## Exception safety
Strong exception safety: if an exception is thrown, `v` is not modified.
- For the directly converted types: strong exception safety. If an exception is thrown, `v` is not modified.
- For every other type: as for [`BasicJsonType::get_to()`](../basic_json/get_to.md). `materialize()` throws before `v`
is touched, but a `from_json()` that throws may leave `v` partly modified.
## Exceptions
Whatever [`get<T>()`](get.md) throws for the same value and `T`.
- For the directly converted types: whatever [`get<T>()`](get.md) throws for the same value and `T`.
- For every other type: whatever [`materialize()`](materialize.md) and
[`BasicJsonType::get_to()`](../basic_json/get_to.md) throw.
## Complexity
Whatever [`get<T>()`](get.md) has for the same `T`.
- For the directly converted types: whatever [`get<T>()`](get.md) has for the same `T`.
- For every other type: that of [`materialize()`](materialize.md), plus that of
[`BasicJsonType::get_to()`](../basic_json/get_to.md).
## Notes
The difference between the two ways matters for a `from_json()` that sets only the fields present in the JSON: since
it runs on the existing `v`, the other fields of `v` keep their values, whereas assigning `get<T>()` would replace
them with those of a default-constructed `T`.
## Examples
docs/mkdocs/docs/api/basic_json_view/index.md
+17 -9
View File
@@ -14,18 +14,27 @@ to the document and a pointer into its index), trivially copyable. A view is val
- the document has not been re-parsed with [`read()`](../basic_json_document/read.md) (or
[`parse()`](../basic_json_document/parse.md) into it) or shrunk with
[`shrink_to_fit()`](../basic_json_document/shrink_to_fit.md) since the view was taken, and
- if the document borrows its source text, that text is still alive.
- if the document borrows its source text, that text is still alive and unmodified (floating-point values and
unescaped strings are read from it lazily).
Moving the document itself does not invalidate its views: the index is heap-allocated independently of the
`basic_json_document` object.
`basic_json_view` provides the read-only part of the `BasicJsonType` interface: the type-inspection functions, element
access, lookup, iteration, conversion, and comparison -- [`get<T>()`](get.md), [`get_string()`](get_string.md),
[`number_token()`](number_token.md), and [`materialize()`](materialize.md) to build the `BasicJsonType` value of a
subtree on demand. [`operator[]`](operator%5B%5D.md), [`at`](at.md), [`contains`](contains.md), and
[`value`](value.md) also accept a [`json_pointer`](../json_pointer/index.md). [`operator==`](operator_eq.md) and
[`operator!=`](operator_ne.md) compare two views, or a view and a `BasicJsonType` value, without ever building a
`BasicJsonType` value for a view; no ordering comparison (`#!cpp operator<`) is provided.
`basic_json_view` provides the read-only part of the `BasicJsonType` interface:
- the type-inspection functions
- element access
- lookup
- iteration
- conversion: [`get<T>()`](get.md), [`get_string()`](get_string.md), [`number_token()`](number_token.md), and
[`materialize()`](materialize.md) to build the `BasicJsonType` value of a subtree on demand
- comparison: [`operator==`](operator_eq.md) and [`operator!=`](operator_ne.md) compare two views, or a view and a
`BasicJsonType` value, without ever building a `BasicJsonType` value for a view; no ordering comparison
(`#!cpp operator<`) is provided
[`operator[]`](operator%5B%5D.md), [`at`](at.md), [`contains`](contains.md), and [`value`](value.md) also accept a
[`json_pointer`](../json_pointer/index.md). Unlike `basic_json`, there are no implicit conversion operators (no
`#!cpp operator ValueType()`), and no `#!cpp get_ptr()` or `#!cpp get_ref()`; see [`get`](get.md).
`basic_json_view` itself is always read-only -- it never has a `set` or `push_back` of its own. A view of an
**editable** document (`#!cpp Editable == true`) sees every edit made through
@@ -61,7 +70,6 @@ still refers to it -- including ones taken before the change -- reads the new va
- **string_view_t** - `#!cpp std::string_view` on C++17 and newer, a minimal internal substitute otherwise
- **iterator**, **const_iterator** - a forward iterator over the elements of an array or the member values of an
object, in document order; both names refer to the same type, since a view is always read-only
- **item** - a (key, value) pair produced by [`items()`](items.md)
- [**number_format**](number_format.md) - how [`dump()`](dump.md) writes numbers
## Member functions
docs/mkdocs/docs/api/basic_json_view/items.md
+9 -9
View File
@@ -4,9 +4,9 @@
/* unspecified */ items() const noexcept;
```
Returns a range of [`item`](index.md#member-types) values -- (key, value) pairs -- for use in range-based for loops.
The key of an array element is its index, converted to a string, as for
[`BasicJsonType::items()`](../basic_json/items.md).
Returns a range of items -- (key, value) pairs -- for use in range-based for loops. An item's `#!cpp key()` is a
`#!cpp string_view_t` (for an array element, its index converted to a string, as for
[`BasicJsonType::items()`](../basic_json/items.md)), and its `#!cpp value()` is a `basic_json_view` of the element.
The returned type is not part of the public API and may change between versions; use a range-based for loop (see the
example), or `#!cpp decltype(v.items())` if you need to name it.
@@ -33,8 +33,8 @@ is nothing for a reference to bind to.
## Return value
A range whose iterators dereference to [`item`](index.md#member-types) and whose `#!cpp begin()`/`#!cpp end()` are
equivalent to [`basic_json_view::begin()`](begin.md)/[`end()`](end.md), in document order.
A range whose iterators dereference to an item (with `#!cpp key()` and `#!cpp value()`, see above) and whose
`#!cpp begin()`/`#!cpp end()` are equivalent to [`basic_json_view::begin()`](begin.md)/[`end()`](end.md), in document order.
## Exception safety
@@ -48,14 +48,14 @@ Constant.
As for [`begin()`](begin.md)/[`end()`](end.md), `items()` visits **every** member of an object, including all
occurrences of a duplicate key -- unlike [`operator[]`](operator[].md), [`at`](at.md), [`find`](find.md),
[`contains`](contains.md), and [`count`](count.md), which resolve to the *first* member with a given key. See the
and [`contains`](contains.md), which resolve to the *first* member with a given key. See the
[Notes on duplicate keys](operator[].md#notes) of `operator[]`.
!!! danger "Lifetime issues"
As for `BasicJsonType::items()`, calling `items()` on a temporary view (or a temporary document) is dangerous:
the range refers back to the document, so the document must outlive the loop. See
[#2040](https://github.com/nlohmann/json/issues/2040) for the `BasicJsonType` background.
Unlike `BasicJsonType::items()` (see [#2040](https://github.com/nlohmann/json/issues/2040)), calling `items()` on
a temporary view is safe, for instance `#!cpp for (auto item : v["a"].items())`: the returned range holds a copy
of the view. What must outlive the loop is the document and, for a borrowed document, the source buffer.
## Examples
docs/mkdocs/docs/api/basic_json_view/number_token.md
+1 -1
View File
@@ -15,7 +15,7 @@ and [`materialize()`](materialize.md) can only represent approximately, as a `nu
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
Strong guarantee: there are no changes to the view or the document it refers to.
## Exceptions
docs/mkdocs/docs/api/basic_json_view/operator[].md
+5 -5
View File
@@ -50,7 +50,7 @@ basic_json_view operator[](const json_pointer& ptr) const;
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
Strong guarantee: there are no changes to the view or the document it refers to.
## Exceptions
@@ -83,8 +83,8 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
another, in document order, stopping at the first match. Each comparison first checks the
key's length -- already known from the index, without reading the key bytes -- before comparing its content, so a
key of a different length than `key` is rejected without touching the source text.
Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
on average.
Objects with 128 or more members get a hash index of their keys while parsing, so that a lookup in them takes
constant time on average.
2. Linear in `idx`: elements are skipped one at a time from the first one, since they are not a fixed size in the
index (unlike `BasicJsonType`'s array, which is random-access).
3. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
@@ -110,13 +110,13 @@ document.
!!! warning "Duplicate keys: the first member wins"
If the source text has an object with a duplicate key, `#!cpp operator[]` (and [`at`](at.md), [`find`](find.md),
[`contains`](contains.md), [`count`](count.md), [`value`](value.md), and JSON pointer resolution) all resolve to
[`contains`](contains.md), [`value`](value.md), and JSON pointer resolution) all resolve to
the *first* member with that key, because a lookup can stop as soon as it finds a match. This is different from
[`materialize()`](materialize.md) (and [`BasicJsonType::parse()`](../basic_json/parse.md)), which replay every
member in order and so keep the *last* value for a repeated key, so `#!cpp v["a"]` and
`#!cpp v.materialize()["a"]` can differ. To get the value `parse()` would give, use
[`materialize()`](materialize.md) or iterate the members with [`items()`](items.md) and keep the last match.
The hash index of a larger object (128 members or more) leads to the first member of a key as well.
The key hash index of a larger object (128 members or more) leads to the first member of a key as well.
[`begin()`](begin.md)/[`end()`](end.md) and [`items()`](items.md) iterate over *all* members, including
duplicates, in document order. See [Duplicate keys](../../features/json_view.md#duplicate-keys) and
[`size()`](size.md#notes).
docs/mkdocs/docs/api/basic_json_view/type_name.md
+8 -8
View File
@@ -14,14 +14,14 @@ same string for a discarded `BasicJsonType` value).
a string representation of the type ([`value_t`](../basic_json/value_t.md)):
| Value type | return value |
|-----------------------------------------------------|---------------|
| `#!json null` | `"null"` |
| boolean | `"boolean"` |
| string | `"string"` |
| number (integer, unsigned integer, floating-point) | `"number"` |
| object | `"object"` |
| array | `"array"` |
| discarded | `"discarded"` |
|----------------------------------------------------|---------------|
| `#!json null` | `"null"` |
| boolean | `"boolean"` |
| string | `"string"` |
| number (integer, unsigned integer, floating-point) | `"number"` |
| object | `"object"` |
| array | `"array"` |
| discarded | `"discarded"` |
`type_name()` never returns `#!cpp "binary"`, since a JSON text has no binary values (see
[`is_binary()`](is_binary.md)); it also never returns `#!cpp "invalid"`, since a view's `#!cpp kind` always comes
docs/mkdocs/docs/api/basic_json_view/value.md
+3 -3
View File
@@ -44,7 +44,7 @@ equivalent) deduce `string_t`, not `const char*`, for their return type and for
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
Strong guarantee: there are no changes to the view or the document it refers to.
## Exceptions
@@ -70,8 +70,8 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
1. Linear in the number of members: as for [`operator[]`](operator[].md#complexity), members are compared one after
another, in document order, stopping at the first match. Plus the complexity of converting
the found member to `T` (see [`get`](get.md)).
Objects with 128 or more members get a hash index while parsing, so that a lookup in them takes constant time
on average.
Objects with 128 or more members get a hash index of their keys while parsing, so that a lookup in them takes
constant time on average.
2. Linear in the number of reference tokens of `ptr` and, for each token, in the number of members of the object at
that level or the index into the array -- as for the [`operator[]`](operator[].md#complexity) and
[`at`](at.md#complexity) overloads that take a JSON pointer. Plus the complexity of converting the resolved value
docs/mkdocs/docs/api/macros/index.md
+5
View File
@@ -16,6 +16,10 @@ header. See also the [macro overview page](../../features/macros.md).
## Parsing
- [**JSON_DISABLE_STREAM_BULK_SCAN**](json_disable_stream_bulk_scan.md) - read a `std::istream` one character at a time
instead of scanning its stream buffer in bulk
- [**JSON_DISABLE_UNLOCKED_FILE_IO**](json_disable_unlocked_file_io.md) - read a `FILE*` with `std::fgetc` instead of
locking it once and using the unlocked stdio functions
- [**JSON_PRECISE_STREAM_POSITION**](json_precise_stream_position.md) - opt in to leaving an input stream positioned
right after a parsed number
- [**JSON_STRICT_BINARY_UTF8**](json_strict_binary_utf8.md) - opt in to checking strings for valid UTF-8 in the CBOR,
@@ -34,6 +38,7 @@ header. See also the [macro overview page](../../features/macros.md).
- [**JSON_HAS_THREE_WAY_COMPARISON**](json_has_three_way_comparison.md) - control 3-way comparison support
- [**JSON_NO_AUTOMATIC_UDLS**](json_no_automatic_udls.md) - do not include the user-defined string literals (UDLs) automatically
- [**JSON_NO_IO**](json_no_io.md) - switch off functions relying on certain C++ I/O headers
- [**JSON_NO_SIMD**](json_no_simd.md) - use only portable code instead of vector instructions (SSE2, SSSE3, NEON)
- [**JSON_NO_THREAD_LOCAL**](json_no_thread_local.md) - switch off the use of `thread_local` storage
- [**JSON_SKIP_UNSUPPORTED_COMPILER_CHECK**](json_skip_unsupported_compiler_check.md) - do not warn about unsupported compilers
- [**JSON_USE_GLOBAL_UDLS**](json_use_global_udls.md) - place user-defined string literals (UDLs) into the global namespace
docs/mkdocs/docs/api/macros/json_disable_stream_bulk_scan.md
+144
View File
@@ -0,0 +1,144 @@
# JSON_DISABLE_STREAM_BULK_SCAN
```cpp
#define JSON_DISABLE_STREAM_BULK_SCAN /* value */
```
When defined to `1`, parsing from a `#!cpp std::istream` reads the input one character at a time through the stream
buffer, as in version 3.12.0 and earlier, instead of scanning the characters that the stream buffer already holds in
bulk.
The macro is an escape hatch for stream buffers that do not follow the usual contract of `std::basic_streambuf` (see
the requirements on the stream buffer in the notes below). It does not change any result: values, exceptions, and the
position of the stream after parsing are the same either way. Only the speed differs.
## Default definition
The default value is `0`: streams are scanned in bulk.
```cpp
#define JSON_DISABLE_STREAM_BULK_SCAN 0
```
## Notes
!!! note "How streams are scanned"
A `std::streambuf` keeps the part of the input it has read but not yet handed out in its *get area*, the range
from `gptr()` to `egptr()`. A `std::filebuf`, for instance, reads the file in blocks of a few kilobytes into its get
area, and a `std::stringbuf` exposes its whole string as one get area.
When parsing from a `std::istream`, the parser scans this get area directly, with the same fast paths that it uses
for a `std::string`: runs of ordinary string characters, numbers, and indentation are recognized several bytes at a
time instead of being requested from the stream buffer one character at a time. When the parser reaches the end of
the get area, it asks the stream buffer for the next character as before, which makes the stream buffer refill its
get area.
The parser only reads characters that it would also have read one at a time, and it advances the stream buffer
exactly over the characters it consumes. Nothing is read ahead, buffered elsewhere, or put back. Therefore, the
stream is left exactly where it was left before:
- [`operator>>`](../operator_gtgt.md) and [`sax_parse`](../basic_json/sax_parse.md) with `strict = false` can still
read several values from one stream, and the stream can still be used with other `std::istream` functions after a
value has been read.
- With [`JSON_PRECISE_STREAM_POSITION`](json_precise_stream_position.md), the stream is still positioned right after
a parsed number.
- Exception messages, including the line, the column, and the last read token, are unchanged.
!!! note "Performance"
Parsing from a `std::ifstream` or `std::istringstream` is typically 1.5 to 2 times as fast as before, and reading
many small values from one stream with `operator>>` 1.4 to 4 times as fast. Parsing from a stream is then within
about 10 to 20 % of first reading the whole file into a `std::string` and parsing that.
A stream buffer without a get area (one that only overrides `underflow()` and `uflow()` and hands out every
character from there) offers nothing to scan in bulk, so it is read one character at a time as before.
!!! note "Requirements on the stream buffer"
The bulk scan relies on the following behavior, which every stream buffer of the standard library and every stream
buffer that keeps its input in its get area has:
- When `sgetc()` returns a character while `gptr() < egptr()`, that character is `*gptr()`; when `sbumpc()` returns
one, it was at `gptr()` before the call.
- Characters in the get area are not changed while they are in the get area.
- `underflow()` or `uflow()` either sets up a get area that holds the returned character at `gptr()` (or at
`gptr() - 1` after `uflow()`), or leaves the get area empty.
A stream buffer that returns characters from `uflow()` while leaving unrelated characters in its get area, or that
changes the characters in its get area in place, does not meet these requirements. Define the macro to `1` for
such stream buffers.
!!! note "ABI compatibility"
The value of this macro is encoded in the [namespace](../../features/namespace.md) (tag `_dsbs`), resulting in
distinct symbol names. Translation units compiled with and without it can therefore be linked into the same program
without One Definition Rule (ODR) violations, but they cannot exchange instances of library types.
!!! note "Other inputs"
Strings, string views, vectors, arrays, and pointer or iterator ranges over contiguous memory are scanned in bulk
anyway. Reading from a `#!cpp FILE*` is not affected by this macro; see
[`JSON_DISABLE_UNLOCKED_FILE_IO`](json_disable_unlocked_file_io.md) for that input.
## Examples
??? example "Example: reading values from a stream (default)"
The stream is scanned in bulk, and the values are read one after the other:
```cpp
#include <iostream>
#include <sstream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
std::istringstream input(R"({"id": 1} {"id": 2} 42 rest)");
json j1, j2, j3;
input >> j1 >> j2 >> j3; // {"id":1}, {"id":2}, 42
std::string word;
input >> word; // "rest"
}
```
??? example "Example: reading one character at a time (macro defined to 1)"
With the macro, the same program reads the stream one character at a time, with the same results:
```cpp
#define JSON_DISABLE_STREAM_BULK_SCAN 1
#include <iostream>
#include <sstream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
std::istringstream input(R"({"id": 1} {"id": 2} 42 rest)");
json j1, j2, j3;
input >> j1 >> j2 >> j3; // {"id":1}, {"id":2}, 42
std::string word;
input >> word; // "rest"
}
```
## See also
- [**parse**](../basic_json/parse.md) - deserialize from a compatible input
- [**operator>>**](../operator_gtgt.md) - deserialize from stream
- [**sax_parse**](../basic_json/sax_parse.md) - generate SAX events
- [**JSON_PRECISE_STREAM_POSITION**](json_precise_stream_position.md) - leave an input stream positioned right after a
parsed number
- [**JSON_DISABLE_UNLOCKED_FILE_IO**](json_disable_unlocked_file_io.md) - read a `FILE*` with the locking stdio
functions
- [Parsing: input sources and performance](../../features/parsing/index.md#input-sources-and-performance)
## Version history
- Added in version 3.13.0.
docs/mkdocs/docs/api/macros/json_disable_unlocked_file_io.md
+115
View File
@@ -0,0 +1,115 @@
# JSON_DISABLE_UNLOCKED_FILE_IO
```cpp
#define JSON_DISABLE_UNLOCKED_FILE_IO /* value */
```
When defined to `1`, parsing from a `#!cpp FILE*` reads every character with `std::fgetc`, as in version 3.12.0 and
earlier, instead of locking the file once and reading it with the unlocked stdio functions.
It does not change any result: values, exceptions, and the position of the file after parsing are the same either way.
Only the speed and the locking of the file differ (see the notes on locking below).
Builds with MemorySanitizer use `std::fgetc` automatically, because the inline `getc_unlocked` of glibc reads the stdio
buffer directly, which glibc (not instrumented) filled, and MemorySanitizer would report it as uninitialized.
## Default definition
The default value is `0`: the file is locked once and read with the unlocked stdio functions where they are available.
```cpp
#define JSON_DISABLE_UNLOCKED_FILE_IO 0
```
## Notes
!!! note "Background"
The C standard library makes every `std::fgetc` call thread-safe by locking and unlocking the `FILE` object. When
parsing from a `FILE*`, the parser reads one character at a time, so this happens for every character of the input.
Instead, the parser locks the file once when parsing starts and unlocks it when parsing ends - also when an
exception is thrown - and reads the characters in between without locking:
| C library | functions |
|------------------------------------------------------------|----------------------------------------------------|
| glibc (Linux), Apple (macOS, iOS), Android, FreeBSD, NetBSD, OpenBSD, DragonFly BSD | `flockfile`, `getc_unlocked`, `funlockfile` (POSIX) |
| Microsoft (MSVC, clang-cl) | `_lock_file`, `_fgetc_nolock`, `_unlock_file` |
| others (e.g., musl, MinGW, newlib) | `std::fgetc`, as before |
This makes parsing from a `FILE*` 3 to 4 times as fast with the Apple C library and 1.1 to 1.3 times as fast with
glibc, whose locking is cheaper. The binary formats ([`from_cbor`](../basic_json/from_cbor.md),
[`from_msgpack`](../basic_json/from_msgpack.md), ...) read from a `FILE*` the same way.
!!! note "Locking"
While a value is parsed from a `FILE*`, the parsing thread holds the file's lock. The lock is recursive, so the
parsing thread itself - for instance, a [SAX](../json_sax/index.md) handler or a
[parser callback](../basic_json/parser_callback_t.md) - can keep using the file with stdio functions such as
`std::ftell`. Other threads that use the same `FILE` object wait until the parser is done. Before, they could
interleave their reads with the parser's, which made the parsed input unpredictable anyway.
A program in which a SAX handler or parser callback waits for **another** thread that uses the **same** `FILE`
object would deadlock. Define the macro to `1` for such programs.
!!! note "ABI compatibility"
The value of this macro is encoded in the [namespace](../../features/namespace.md) (tag `_dufio`), resulting in
distinct symbol names. Translation units compiled with and without it can therefore be linked into the same program
without One Definition Rule (ODR) violations, but they cannot exchange instances of library types.
!!! note "Other inputs"
Reading from a `#!cpp std::istream` is not affected by this macro; see
[`JSON_DISABLE_STREAM_BULK_SCAN`](json_disable_stream_bulk_scan.md) for that input.
## Examples
??? example "Example: parsing from a `FILE*` (default)"
The file is locked once while it is parsed:
```cpp
#include <cstdio>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
std::FILE* f = std::fopen("example.json", "rb");
json j = json::parse(f); // f is locked until parse() returns
std::fclose(f);
}
```
??? example "Example: locking for every character (macro defined to 1)"
With the macro, every character is read with `std::fgetc`, with the same result:
```cpp
#define JSON_DISABLE_UNLOCKED_FILE_IO 1
#include <cstdio>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
std::FILE* f = std::fopen("example.json", "rb");
json j = json::parse(f); // std::fgetc for every character
std::fclose(f);
}
```
## See also
- [**parse**](../basic_json/parse.md) - deserialize from a compatible input
- [**sax_parse**](../basic_json/sax_parse.md) - generate SAX events
- [**JSON_DISABLE_STREAM_BULK_SCAN**](json_disable_stream_bulk_scan.md) - read a `std::istream` one character at a
time
- [Parsing: input sources and performance](../../features/parsing/index.md#input-sources-and-performance)
## Version history
- Added in version 3.13.0.
docs/mkdocs/docs/api/macros/json_no_simd.md
+83
View File
@@ -0,0 +1,83 @@
# JSON_NO_SIMD
```cpp
#define JSON_NO_SIMD
```
When defined, the library uses only portable C++ code where it would otherwise use vector instructions: when scanning
strings during parsing, and when writing floating-point numbers during serialization.
The macro is an escape hatch, for example for toolchains that cannot compile the vector code, for sanitizers or
analyzers that do not understand it, or to compare the speed of both variants. It does not change any result: values,
exceptions, and error positions are the same either way. Only the speed differs.
## Default definition
By default, `#!cpp JSON_NO_SIMD` is not defined, and vector instructions are used where the target has them.
```cpp
#undef JSON_NO_SIMD
```
## Notes
!!! note "Which instructions are used"
- **x86-64:** SSE2, which every x86-64 CPU has, finds the end of runs of plain string characters 16 bytes at a time
and writes the digits of floating-point numbers. The UTF-8 check of non-ASCII text needs SSSE3, which is not part
of x86-64: it is compiled for SSSE3 with a function attribute and used when the CPU has SSSE3 (every x86-64 CPU
since about 2011), else the portable check. Code compiled for SSSE3 anyway (e.g., with `-mssse3` or `-march=native`)
skips this check of the CPU. 32-bit x86 uses SSE2 for strings when the compiler targets it.
- **AArch64:** NEON, which every 64-bit Arm CPU has, checks UTF-8 text and long runs of plain string characters 16
bytes at a time, and writes the digits of floating-point numbers. With MSVC, only the floating-point digits use
NEON.
- **Other targets:** portable code only.
Strings are only scanned this way for contiguous input and for the characters a `#!cpp std::istream` holds in its
stream buffer (see [`JSON_DISABLE_STREAM_BULK_SCAN`](json_disable_stream_bulk_scan.md)); other inputs are read one
character at a time.
!!! note "Interaction with `JSON_USE_SIMDUTF`"
With [`JSON_USE_SIMDUTF`](json_use_simdutf.md), runs of string characters are first validated by simdutf; the code
described here is used for what simdutf does not accept, so that errors are reported at the same position.
`JSON_NO_SIMD` does not affect simdutf.
!!! warning "Define consistently"
The macro selects between two definitions of the library's internal scanning and formatting functions. It must
therefore be defined identically for **every** translation unit that includes the library; mixing translation units
that define it with ones that do not is an ODR violation. Prefer setting it as a compile definition on the target
rather than with `#!cpp #define` in individual source files.
## Examples
??? example "Example: switching off vector instructions"
The program parses and serializes the same values with and without the macro:
```cpp
#define JSON_NO_SIMD
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
int main()
{
const json j = json::parse(R"({"name": "日本語 text", "pi": 3.141592653589793})");
std::cout << j.dump() << '\n'; // {"name":"日本語 text","pi":3.141592653589793}
}
```
## See also
- [**parse**](../basic_json/parse.md) - deserialize from a compatible input
- [**dump**](../basic_json/dump.md) - serialization
- [**JSON_USE_SIMDUTF**](json_use_simdutf.md) - use the simdutf library to accelerate UTF-8 validation
- [**JSON_DISABLE_STREAM_BULK_SCAN**](json_disable_stream_bulk_scan.md) - read a `std::istream` one character at a time
- [Parsing: input sources and performance](../../features/parsing/index.md#input-sources-and-performance)
## Version history
- Added in version 3.13.0.
docs/mkdocs/docs/api/macros/json_precise_stream_position.md
+6
View File
@@ -72,6 +72,12 @@ The default value is `0` (disabled — existing behavior is preserved).
distinct symbol names. Translation units compiled with and without it can therefore be linked into the same program
without One Definition Rule (ODR) violations, but they cannot exchange instances of library types.
!!! note "Bulk scanning"
The parser scans the characters in the stream buffer in bulk (see
[`JSON_DISABLE_STREAM_BULK_SCAN`](json_disable_stream_bulk_scan.md)), but it never reads ahead. The stream is left
at the same position with and without bulk scanning, in both modes of this macro.
!!! tip "Workaround without the macro"
Separate the values in the stream with whitespace. The character consumed after a number is then the separator,
docs/mkdocs/docs/api/macros/json_use_simdutf.md
+6 -4
View File
@@ -6,14 +6,16 @@
When defined, the parser validates the UTF-8 content of JSON strings that come from a **contiguous byte input**
(`std::string`, `std::vector<char>`/`<std::uint8_t>`, string literals, `const char*` ranges, …) using the
[simdutf](https://github.com/simdutf/simdutf) library instead of the built-in scalar validator. On text with many
non-ASCII characters (e.g. CJK or emoji) this can validate several times faster.
[simdutf](https://github.com/simdutf/simdutf) library instead of the built-in validator (which uses SSSE3 or NEON where
available, see [`JSON_NO_SIMD`](json_no_simd.md)). On text with many non-ASCII characters (e.g. CJK or emoji) this can
validate faster, depending on the CPU.
This is an **opt-in external dependency**. The library itself remains header-only and its behavior is unchanged: the
same input is accepted or rejected either way, and every parse error is reported at the same position with the same
message (simdutf is only used to fast-path *valid* runs; anything it flags falls back to the scalar path so the exact
diagnostic is preserved). Streaming inputs (files, `std::istream`, wide strings, user-defined adapters) always use the
scalar path.
diagnostic is preserved). A `std::istream` uses simdutf for the characters its stream buffer holds (see
[`JSON_DISABLE_STREAM_BULK_SCAN`](json_disable_stream_bulk_scan.md)); other streaming inputs (`FILE*`, wide strings,
user-defined adapters) always use the scalar path.
When `JSON_USE_SIMDUTF` is defined you must make the `simdutf.h` header available on the include path and link the
simdutf library. When it is not defined, no simdutf header is included and there is no dependency.
docs/mkdocs/docs/api/macros/json_view_no_simd.md
+5 -3
View File
@@ -14,10 +14,12 @@ The same input is accepted or rejected either way, with the same values, and err
the speed differs. The macro exists for platforms whose compilers lack the intrinsics headers, and to test the portable
code.
!!! warning "Define consistently"
!!! note "ABI compatibility"
The macro selects between two definitions of the same inline functions. It must therefore be defined identically for
**every** translation unit that includes `<nlohmann/json_view.hpp>`; prefer a compile definition on the target.
The macro selects between two definitions of the same inline functions. Whether it is defined is encoded in the
[namespace](../../features/namespace.md) (tag `_vns`), resulting in distinct symbol names. Translation units
compiled with and without it can therefore be linked into the same program without One Definition Rule (ODR)
violations, but they cannot exchange instances of library types.
## Default definition
docs/mkdocs/docs/api/macros/json_view_use_ssse3.md
+5 -5
View File
@@ -17,12 +17,12 @@ Define the macro only together with a compiler option that enables SSSE3 (e.g. `
has it), and only for programs that run on such CPUs. It saves the check of the CPU, which costs little. The same
input is accepted or rejected either way; only the speed of non-ASCII text differs.
!!! warning "Define consistently"
!!! note "ABI compatibility"
The macro selects between two definitions of the same inline functions. It must therefore be defined identically,
with the same compiler options, for **every** translation unit that includes `<nlohmann/json_view.hpp>`; mixing
translation units that define it with ones that do not is an ODR violation. Prefer a compile definition on the
target.
The macro selects between two definitions of the same inline functions. Whether it is defined is encoded in the
[namespace](../../features/namespace.md) (tag `_vssse3`, on every architecture), resulting in distinct symbol
names. Translation units compiled with and without it can therefore be linked into the same program without One
Definition Rule (ODR) violations, but they cannot exchange instances of library types.
## Default definition
docs/mkdocs/docs/api/macros/nlohmann_json_namespace.md
+2 -1
View File
@@ -39,5 +39,6 @@ the library.
## Version history
- Added in version 3.11.0. Changed inline namespace name in version 3.11.2. Added the ABI tag `_dp` in
version 3.12.0, and the ABI tags `_bics`, `_psp`, `_snul`, `_sbu8`, and `_ekmo` in version 3.13.0; see
version 3.12.0, and the ABI tags `_bics`, `_psp`, `_snul`, `_sbu8`, `_ekmo`, `_dsbs`, `_dufio`, `_vns`, and
`_vssse3` in version 3.13.0; see
[`nlohmann` Namespace](../../features/namespace.md#structure).
docs/mkdocs/docs/api/operator_gtgt.md
+4
View File
@@ -121,6 +121,7 @@ being read.
- [`JSON_STRICT_NUL_HANDLING`](macros/json_strict_nul_handling.md) - opt in to rejecting a NUL byte in the input
instead of treating it as end of input
- [`JSON_PRECISE_STREAM_POSITION`](macros/json_precise_stream_position.md) - opt in to leaving the stream positioned right after a number
- [`JSON_DISABLE_STREAM_BULK_SCAN`](macros/json_disable_stream_bulk_scan.md) - read the stream one character at a time
## Version history
@@ -133,3 +134,6 @@ being read.
crash (`std::terminate`) when `i` has `eofbit` in its exception mask, in version 3.13.0.
- Changed to the strong exception safety guarantee in version 3.13.0: `j` is no longer left with a partially parsed
value if parsing throws.
- Scans the characters in the stream buffer of `i` in bulk in version 3.13.0; the position of `i` after the call is
unchanged ([`JSON_DISABLE_STREAM_BULK_SCAN`](macros/json_disable_stream_bulk_scan.md) restores reading one character
at a time).
docs/mkdocs/docs/community/quality_assurance.md
+3
View File
@@ -135,6 +135,9 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
headers are included.
- [x] On Windows, the library is compiled with `<Windows.h>` being included to detect and avoid common bugs (see
[`unit-windows_h.cpp`](https://github.com/nlohmann/json/blob/develop/tests/src/unit-windows_h.cpp)).
- [x] The library is compiled with Qt's keyword macros (`slots`, `signals`, `emit`, `foreach`, `forever`) being defined
to make sure it does not use them as identifiers (see
[`unit-qt_keywords.cpp`](https://github.com/nlohmann/json/blob/develop/tests/src/unit-qt_keywords.cpp)).
- [x] The library is compiled with exceptions disabled to support alternative means of error handling.
## Stable public API
docs/mkdocs/docs/examples/basic_json_view__count.cpp
+7 -5
View File
@@ -5,13 +5,14 @@ using json_document = nlohmann::json_document;
int main()
{
// validate that every transaction of a batch carries a mandatory
// validate that every transaction of a batch carries exactly one
// "amount" field before materializing any of them into a nlohmann::json
// value -- count() returns 0 or 1 for an object
// value -- count() counts every member with the key
json_document batch = json_document::parse(R"(
[
{"id": 1, "amount": 9.99},
{"id": 2}
{"id": 2},
{"id": 3, "amount": 5.00, "amount": 500.00}
]
)");
@@ -19,9 +20,10 @@ int main()
for (std::size_t i = 0; i < transactions.size(); ++i)
{
const auto transaction = transactions[i];
if (transaction.count("amount") == 0)
const auto amounts = transaction.count("amount");
if (amounts != 1)
{
std::cout << "transaction " << i << " is missing \"amount\"\n";
std::cout << "transaction " << i << " has " << amounts << " \"amount\" fields\n";
continue;
}
std::cout << "transaction " << i << ": " << transaction["amount"].materialize().dump() << '\n';
docs/mkdocs/docs/examples/basic_json_view__count.output
+2 -1
View File
@@ -1,2 +1,3 @@
transaction 0: 9.99
transaction 1 is missing "amount"
transaction 1 has 0 "amount" fields
transaction 2 has 2 "amount" fields
docs/mkdocs/docs/features/index.md
+2 -2
View File
@@ -14,8 +14,8 @@ C++ types, and finally serialize it again.
[parsing untrusted input](parsing/untrusted_input.md).
- [Zero-copy JSON views](json_view.md) — read a JSON text through a flat index instead of building a `json` tree;
strings and numbers stay in the input and are only decoded when needed.
[Editable documents](json_view.md#editing-a-document) can also be modified, and [images](json_view.md#images) load a
parsed document again without parsing it.
- [Editable documents](json_view.md#editing-a-document) — modify a parsed document without building a `json` tree.
- [Images](json_view.md#images) — save a parsed document and load it again without parsing it.
- [Comments](comments.md) and [trailing commas](trailing_commas.md) — opt-in relaxations of the JSON grammar.
## Accessing and modifying values
docs/mkdocs/docs/features/json_view.md
+13 -11
View File
@@ -16,8 +16,9 @@ most of the resulting tree is thrown away almost immediately.
[`basic_json_document::parse()`](../api/basic_json_document/parse.md) parses the same JSON grammar, with the same
options, but instead of a tree it builds a flat index of the values it found: one
[16-byte entry](../home/architecture.md#node-index-of-json-views) per value (and one per object key), in document
order. Strings and numbers are referenced in place in the source text; only strings that contain escape sequences
are decoded, into one shared buffer owned by the document.
order. Integers are converted while parsing and stored in their entry. Floating-point numbers and strings are
referenced in place in the source text: a float is converted when it is read, and only strings that contain escape
sequences are decoded, into one shared buffer owned by the document.
[`basic_json_view`](../api/basic_json_view/index.md) is a small, trivially copyable handle (two pointers) into that
index. It gives you the read-only, type-inspection part of the `basic_json` interface --
@@ -66,9 +67,10 @@ table). [`parse_copy()`](../api/basic_json_document/parse_copy.md) always owns a
!!! warning "A borrowed document depends on your buffer"
If a document borrows its text, that text **must outlive the document** (and every view taken from it). Reading
or writing through a view after the underlying buffer is gone is undefined behavior, exactly as it would be for
a dangling `#!cpp std::string_view`.
If a document borrows its text, that text **must outlive the document** (and every view taken from it) and must
stay **unmodified** for as long as the document exists, since floating-point values and unescaped strings are
read from it lazily. Reading or writing through a view after the underlying buffer is gone is undefined behavior,
exactly as it would be for a dangling `#!cpp std::string_view`.
A view is valid only while all of the following hold:
@@ -76,7 +78,7 @@ A view is valid only while all of the following hold:
- the document has not been re-parsed since the view was taken (with [`read()`](../api/basic_json_document/read.md)
or [`parse()`](../api/basic_json_document/parse.md) into it),
- the document has not had [`shrink_to_fit()`](../api/basic_json_document/shrink_to_fit.md) called on it since, and
- if the document borrows its source text, that text is still alive.
- if the document borrows its source text, that text is still alive and unmodified.
Moving the `basic_json_document<>` itself is fine and does **not** invalidate its views: the index is a separate heap
allocation that keeps its address across the move. Take a fresh view from [`root()`](../api/basic_json_document/root.md)
@@ -166,10 +168,10 @@ document: `#!cpp auto v = json_document::parse(text).root();` does not compile.
If an object in the source text repeats a key, [`operator[]`](../api/basic_json_view/operator%5B%5D.md),
[`at`](../api/basic_json_view/at.md), [`find`](../api/basic_json_view/find.md),
[`value`](../api/basic_json_view/value.md), [`contains`](../api/basic_json_view/contains.md),
[`count`](../api/basic_json_view/count.md), and JSON pointer resolution all return the **first** member with that
key. `basic_json::parse()` instead keeps the **last** value of a repeated key, so for `#!cpp {"a":1,"a":2}`,
`#!cpp view["a"]` is `#!cpp 1` while `#!cpp parse(text)["a"]` is `#!cpp 2`.
[`value`](../api/basic_json_view/value.md), [`contains`](../api/basic_json_view/contains.md), and JSON pointer
resolution all return the **first** member with that key. `basic_json::parse()` instead keeps the **last** value
of a repeated key, so for `#!cpp {"a":1,"a":2}`, `#!cpp view["a"]` is `#!cpp 1` while `#!cpp parse(text)["a"]` is
`#!cpp 2`. [`count`](../api/basic_json_view/count.md) counts every member with the key, so it is `#!cpp 2` here.
[`begin()`](../api/basic_json_view/begin.md)/[`end()`](../api/basic_json_view/end.md) and
[`items()`](../api/basic_json_view/items.md) visit *every* occurrence, in document order, and
@@ -178,7 +180,7 @@ document: `#!cpp auto v = json_document::parse(text).root();` does not compile.
**Why the first?** A lookup can stop as soon as it finds a match. Returning the last member would force every lookup
to scan all members of the object, even when the key is found at the very first one: this made lookups in small
objects 1.6 to 3.4 times slower. The hash index of objects with 128 members or more leads to the first member of a
objects 1.6 to 3.4 times slower. The hash index of the keys of objects with 128 members or more leads to the first member of a
key as well. Other zero-copy parsers that index the source text, such as yyjson and simdjson, also return the first
member. RFC 8259 only says that names within an object SHOULD be unique and that the behavior of a receiver that sees
duplicates is unpredictable, so neither choice is wrong.
docs/mkdocs/docs/features/macros.md
+23
View File
@@ -133,6 +133,14 @@ When defined, default parse and serialize functions for enums are excluded and h
See [full documentation of `JSON_DISABLE_ENUM_SERIALIZATION`](../api/macros/json_disable_enum_serialization.md).
## `JSON_DISABLE_STREAM_BULK_SCAN`
When defined to `1`, parsing from a `#!cpp std::istream` reads one character at a time instead of scanning the
characters that the stream buffer holds in bulk. Results are the same either way; the macro is an escape hatch for
stream buffers that do not follow the usual `std::streambuf` contract. The default value is `0`.
See [full documentation of `JSON_DISABLE_STREAM_BULK_SCAN`](../api/macros/json_disable_stream_bulk_scan.md).
## `JSON_DISABLE_TUPLE_REFERENCE_CONVERSION`
When defined to `1`, a JSON value can no longer be created from a one-element `std::tuple` holding a reference to a JSON
@@ -141,6 +149,14 @@ is planned to become the default in version 4.0.0.
See [full documentation of `JSON_DISABLE_TUPLE_REFERENCE_CONVERSION`](../api/macros/json_disable_tuple_reference_conversion.md).
## `JSON_DISABLE_UNLOCKED_FILE_IO`
When defined to `1`, parsing from a `#!cpp FILE*` reads every character with `std::fgetc`, which locks the file each
time, instead of locking the file once and reading it with the unlocked stdio functions. Results are the same either
way. The default value is `0`.
See [full documentation of `JSON_DISABLE_UNLOCKED_FILE_IO`](../api/macros/json_disable_unlocked_file_io.md).
## `JSON_NO_AUTOMATIC_UDLS`
When defined, `<nlohmann/json.hpp>` does not include `<nlohmann/json_literals.hpp>` with the user-defined string literals
@@ -158,6 +174,13 @@ security reasons (e.g., Intel Software Guard Extensions (SGX)).
See [full documentation of `JSON_NO_IO`](../api/macros/json_no_io.md).
## `JSON_NO_SIMD`
When defined, the library uses only portable code instead of vector instructions (SSE2, SSSE3, NEON) for scanning
strings and writing floating-point numbers. Results are the same either way. It is not defined by default.
See [full documentation of `JSON_NO_SIMD`](../api/macros/json_no_simd.md).
## `JSON_NO_THREAD_LOCAL`
When defined, the library does not use `#!cpp thread_local` storage. Copying a value and comparing two values then
docs/mkdocs/docs/features/namespace.md
+12 -2
View File
@@ -23,6 +23,12 @@ The complete default namespace name is derived as follows:
- [`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md) defined non-zero appends `_sbu8`.
- [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md) defined non-zero
appends `_ekmo`.
- [`JSON_DISABLE_STREAM_BULK_SCAN`](../api/macros/json_disable_stream_bulk_scan.md) defined non-zero appends
`_dsbs`.
- [`JSON_DISABLE_UNLOCKED_FILE_IO`](../api/macros/json_disable_unlocked_file_io.md) defined non-zero appends
`_dufio`.
- [`JSON_VIEW_NO_SIMD`](../api/macros/json_view_no_simd.md) defined appends `_vns`.
- [`JSON_VIEW_USE_SSSE3`](../api/macros/json_view_use_ssse3.md) defined appends `_vssse3`.
- The inline namespace ends with the suffix `_v` followed by the 3 components of the version number separated by
underscores. To omit the version component, see [Disabling the version component](#disabling-the-version-component)
below.
@@ -105,5 +111,9 @@ follows:
- Added ABI tags `_bics` ([`JSON_BRACE_INIT_COPY_SEMANTICS`](../api/macros/json_brace_init_copy_semantics.md)), `_psp`
([`JSON_PRECISE_STREAM_POSITION`](../api/macros/json_precise_stream_position.md)), `_snul`
([`JSON_STRICT_NUL_HANDLING`](../api/macros/json_strict_nul_handling.md)), `_sbu8`
([`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md)), and `_ekmo`
([`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md)) in version 3.13.0.
([`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md)), `_ekmo`
([`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md)), `_dsbs`
([`JSON_DISABLE_STREAM_BULK_SCAN`](../api/macros/json_disable_stream_bulk_scan.md)), `_dufio`
([`JSON_DISABLE_UNLOCKED_FILE_IO`](../api/macros/json_disable_unlocked_file_io.md)), `_vns`
([`JSON_VIEW_NO_SIMD`](../api/macros/json_view_no_simd.md)), and `_vssse3`
([`JSON_VIEW_USE_SSSE3`](../api/macros/json_view_use_ssse3.md)) in version 3.13.0.
docs/mkdocs/docs/features/parsing/index.md
+28
View File
@@ -55,6 +55,34 @@ whitespace, because `operator>>` consumes the character that terminates a number
[`JSON_PRECISE_STREAM_POSITION`](../../api/macros/json_precise_stream_position.md) is defined to `1` — see the
[`operator>>` notes](../../api/operator_gtgt.md#notes) for details and examples.
## Input sources and performance
All inputs produce the same values and the same exceptions, but they are read in different ways, which makes some of
them faster than others:
| input | how it is read |
|--------------------------------------------------------------------------------------------|------------------------------------------------------------------------------------|
| strings, string views, string literals, contiguous containers, pointer or iterator ranges over contiguous memory | the whole input is scanned in bulk: runs of string characters, numbers, and indentation are recognized several bytes at a time |
| `#!cpp std::istream` (`#!cpp std::ifstream`, `#!cpp std::istringstream`, ...) | the characters the stream buffer holds are scanned in bulk like a string; the stream buffer is asked for more when they are used up |
| `#!cpp FILE*` | one character at a time, with the file locked once for the whole parse |
| other iterator ranges (e.g., `#!cpp std::list<char>`, `#!cpp std::istreambuf_iterator<char>`), wide strings | one character at a time |
Parsing a file from a `#!cpp std::ifstream` is therefore only about 10 to 20 % slower than reading the whole file into a
`#!cpp std::string` first and parsing that, and it needs no memory for a copy of the file. The stream is never read
ahead: after parsing, it is positioned exactly as if every character had been read one at a time, so
[`operator>>`](../../api/operator_gtgt.md) can still read several values from one stream (see also
[JSON Lines](json_lines.md)).
Two macros switch these optimizations off without changing any result:
[`JSON_DISABLE_STREAM_BULK_SCAN`](../../api/macros/json_disable_stream_bulk_scan.md) for stream buffers that do not
follow the usual `std::streambuf` contract, and
[`JSON_DISABLE_UNLOCKED_FILE_IO`](../../api/macros/json_disable_unlocked_file_io.md) for programs in which another
thread must use the same `#!cpp FILE` object while it is parsed.
Where the target has them, strings are scanned with vector instructions: SSE2 on x86-64 (and SSSE3 for UTF-8 text, when
the CPU has it) and NEON on AArch64. [`JSON_NO_SIMD`](../../api/macros/json_no_simd.md) selects portable code instead,
again without changing any result.
## SAX vs. DOM parsing
The library offers two parsing models:
docs/mkdocs/docs/features/performance.md
+28 -21
View File
@@ -20,32 +20,39 @@ below apply on every supported standard. This adapter exposes two optimizations
- it can reconstruct already-consumed input on demand for error messages, instead of copying every character as it is
read, and
- the lexer can scan ordinary string characters directly out of the buffer, several bytes at a time, rather than one
character (and one function call) at a time.
- the lexer can scan ordinary string characters, numbers, and indentation directly out of the buffer, several bytes at
a time, rather than one character (and one function call) at a time.
A `#!cpp std::istream` (including `#!cpp std::ifstream`) or `#!cpp FILE*`, by contrast, is read through
`input_stream_adapter` or `file_input_adapter`, which read one character (or one block, for binary formats) at a time
and expose neither optimization -- the lexer falls back to the same byte-at-a-time path it uses for any
non-contiguous, general-purpose iterator range. An iterator pair over non-contiguous but random-access storage (e.g.
`#!cpp std::deque<char>::iterator`) gets the first optimization but not the second, since the byte-scanning fast path
additionally requires contiguous storage.
A `#!cpp std::istream` (including `#!cpp std::ifstream`) gets the same bulk scanning: `input_stream_adapter` scans the
characters its stream buffer already holds (the *get area*) and asks the stream buffer for more only when they are used
up. Nothing is read ahead, so the stream is left exactly where it would be after reading one character at a time, and
[`operator>>`](../api/operator_gtgt.md) can still read several values from one stream. A stream buffer without a get
area is read one character at a time. A `#!cpp FILE*` is still read one character at a time, but `file_input_adapter`
locks the file once per parse instead of once per character. See
[input sources and performance](parsing/index.md#input-sources-and-performance) for the full table. According to the
description of [#5828](https://github.com/nlohmann/json/pull/5828), parsing from a stream is within about 10 to 20 % of
parsing an equivalent `#!cpp std::string`.
Practically: if the JSON text is already in memory, or small enough to read into memory, prefer passing a
`#!cpp std::string`, a `#!cpp std::vector<char>`, or a pointer range to `parse` over a `#!cpp std::istream`. For a
file, that means reading it into a string first and then parsing the string, rather than passing a
`#!cpp std::ifstream` directly to `parse` -- the latter never benefits from either optimization:
Inputs that are still read one character at a time: iterator ranges that are not contiguous (e.g.
`#!cpp std::list<char>` or `#!cpp std::istreambuf_iterator<char>`), wide strings, and user-defined adapters. An
iterator pair over non-contiguous but random-access storage (e.g. `#!cpp std::deque<char>::iterator`) gets the first
optimization but not the second, since the byte-scanning fast path requires contiguous storage.
Practically: a file can be passed directly to `parse`, which also avoids the memory for a copy of the file. Reading it
into a string first is no longer necessary for speed:
```cpp
// gets the contiguous fast paths
// fast: the stream buffer's get area is scanned in bulk
std::ifstream f("example.json");
std::string contents((std::istreambuf_iterator<char>(f)), std::istreambuf_iterator<char>());
json j = json::parse(contents);
// does not: input_stream_adapter has no fast path
std::ifstream f2("example.json");
json j2 = json::parse(f2);
json j = json::parse(f);
```
Two macros switch the stream optimizations off without changing any result:
[`JSON_DISABLE_STREAM_BULK_SCAN`](../api/macros/json_disable_stream_bulk_scan.md) for stream buffers that do not follow
the usual `#!cpp std::streambuf` contract, and
[`JSON_DISABLE_UNLOCKED_FILE_IO`](../api/macros/json_disable_unlocked_file_io.md) for programs in which another thread
must use the same `#!cpp FILE` object while it is parsed.
For contiguous input with many non-ASCII characters, [`JSON_USE_SIMDUTF`](../api/macros/json_use_simdutf.md) can
additionally speed up UTF-8 validation by using the [simdutf](https://github.com/simdutf/simdutf) library instead of
the built-in scalar validator; streaming inputs (files, `#!cpp std::istream`, wide strings, user-defined adapters)
@@ -65,8 +72,8 @@ a DOM, three alternatives avoid building it:
unparsed remainder of the input) instead of the whole document -- see the [recipe for streaming a large homogeneous
array](parsing/parser_callbacks.md#recipe-streaming-a-large-homogeneous-array).
- Parse into a [`json_document`](json_view.md) (`#!cpp <nlohmann/json_view.hpp>`) instead of a `basic_json`. It keeps
the input text and builds a flat index of 16 bytes per value; strings and numbers are not copied, but read from the
text when needed. Read-only [views](../api/basic_json_view/index.md) give the familiar element access, and only the
the input text and builds a flat index of 16 bytes per value; strings and floating-point numbers are not copied, but
read from the text when needed. Read-only [views](../api/basic_json_view/index.md) give the familiar element access, and only the
parts you [`materialize()`](../api/basic_json_view/materialize.md) become `basic_json` values. A document that
borrows the text instead of owning a copy needs the text to outlive it; see
[choosing between `json`, the SAX interface, and `json_view`](json_view.md#choosing-between-json-ordered_json-the-sax-interface-and-json_view).
docs/mkdocs/docs/features/types/index.md
+8 -8
View File
@@ -120,7 +120,7 @@ requirements are collected in [Template Parameter Requirements](template_paramet
### Default type
With the default values for *ObjectType* (`std::map`), *StringType* (`std::string`), and *AllocatorType* (`std::allocator`), the default value for `object_t` is:
With the default values for *ObjectType* (`std::map`), *StringType* (`std::string`), and *AllocatorType* (`std::allocator`), the default type for `object_t` is:
```cpp
std::map<
@@ -177,7 +177,7 @@ json j = m;
### Default type
With the default values for *ArrayType* (`std::vector`) and *AllocatorType* (`std::allocator`), the default value for `array_t` is:
With the default values for *ArrayType* (`std::vector`) and *AllocatorType* (`std::allocator`), the default type for `array_t` is:
```cpp
std::vector<
@@ -209,7 +209,7 @@ Unicode values are split by the JSON class into byte-sized characters during des
### Default type
With the default values for *StringType* (`std::string`), the default value for `string_t` is `#!cpp std::string`.
With the default values for *StringType* (`std::string`), the default type for `string_t` is `#!cpp std::string`.
### Encoding
@@ -234,7 +234,7 @@ String values are stored as pointers in a `basic_json` type. That is, for any ac
### Default type
With the default values for *BooleanType* (`#!cpp bool`), the default value for `boolean_t` is `#!cpp bool`.
With the default values for *BooleanType* (`#!cpp bool`), the default type for `boolean_t` is `#!cpp bool`.
### Storage
@@ -252,9 +252,9 @@ This description includes both integer and floating-point numbers. However, C++
### Default types
With the default values for *NumberIntegerType* (`std::int64_t`), the default value for `number_integer_t` is `std::int64_t`.
With the default values for *NumberUnsignedType* (`std::uint64_t`), the default value for `number_unsigned_t` is `std::uint64_t`.
With the default values for *NumberFloatType* (`#!cpp double`), the default value for `number_float_t` is `#!cpp double`.
With the default values for *NumberIntegerType* (`std::int64_t`), the default type for `number_integer_t` is `std::int64_t`.
With the default values for *NumberUnsignedType* (`std::uint64_t`), the default type for `number_unsigned_t` is `std::uint64_t`.
With the default values for *NumberFloatType* (`#!cpp double`), the default type for `number_float_t` is `#!cpp double`.
### Default behavior
@@ -281,7 +281,7 @@ As this range is a subrange of the exactly supported range [`INT64_MIN`, `INT64_
> This specification allows implementations to set limits on the range and precision of numbers accepted. Since software that implements IEEE 754-2008 binary64 (double precision) numbers is generally available and widely used, good interoperability can be achieved by implementations that expect no more precision or range than these provide, in the sense that implementations will approximate JSON numbers within the expected precision.
This implementation does exactly follow this approach, as it uses double precision floating-point numbers. Note that numbers smaller than `#!c -1.79769313486232e+308` or greater than `#!c 1.79769313486232e+308` are rejected during parsing with [`out_of_range.406`](../../home/exceptions.md#jsonexceptionout_of_range406). Non-finite values (NaN and infinity) can only be stored by assigning them directly and are serialized to `#!json null`.
This implementation does exactly follow this approach, as it uses double precision floating-point numbers by default (see *NumberFloatType* above). Note that with the default `#!cpp double`, numbers smaller than `#!c -1.79769313486232e+308` or greater than `#!c 1.79769313486232e+308` are rejected during parsing with [`out_of_range.406`](../../home/exceptions.md#jsonexceptionout_of_range406). Non-finite values (NaN and infinity) can only be stored by assigning them directly and are serialized to `#!json null`.
### Storage
docs/mkdocs/docs/features/types/number_handling.md
+5 -2
View File
@@ -345,8 +345,11 @@ The number types can be changed with template parameters.
in case of overflow.
- The type for unsigned integers must be convertible from `#!c unsigned long long`. The type for floating-point
numbers is used in case of overflow.
- The types for signed and unsigned integers must be distinct, see
[#2573](https://github.com/nlohmann/json/issues/2573).
- The type for unsigned integers can also be the same signed type as the type for signed integers (e.g.,
`#!c std::int64_t` for both). Then every integer is stored as a signed integer, and
[`is_number_unsigned()`](../../api/basic_json/is_number_unsigned.md) is always `#!c false`, see
[Template Parameter Requirements](template_parameters.md#same-type-for-both).
- The type for floating-point numbers must be distinct from the integer types.
- Only `#!c double`, `#!c float`, and `#!c long double` are supported for floating-point numbers.
!!! example
docs/mkdocs/docs/features/types/template_parameters.md
+38 -19
View File
@@ -40,19 +40,19 @@ Requirements are split into two groups:
## Overview
| Template parameter | Default | Notable substitutes |
|-------------------------------------------------------------------|-----------------------------------|-----------------------------------------------------------------------|
| [`ObjectType`](#objecttype) | `std::map` | [`nlohmann::ordered_map`](../../api/ordered_map.md), Abseil hash maps |
| [`ArrayType`](#arraytype) | `std::vector` | `#!cpp std::deque` |
| [`StringType`](#stringtype) | `std::string` | `std::string`-like types over `char` |
| [`BooleanType`](#booleantype) | `bool` | none worth using |
| [`NumberIntegerType`](#numberintegertype-and-numberunsignedtype) | `std::int64_t` | any signed integer type |
| [`NumberUnsignedType`](#numberintegertype-and-numberunsignedtype) | `std::uint64_t` | any unsigned integer type at least as wide as `NumberIntegerType` |
| [`NumberFloatType`](#numberfloattype) | `double` | `float` (`long double`: no binary formats) |
| [`AllocatorType`](#allocatortype) | `std::allocator` | stateless allocators |
| [`JSONSerializer`](#jsonserializer) | `adl_serializer` | serializers with the same interface |
| [`BinaryType`](#binarytype) | `#!cpp std::vector<std::uint8_t>` | `#!cpp std::vector<char>` |
| [`CustomBaseClass`](#custombaseclass) | `void` | any default-constructible class |
| Template parameter | Default | Notable substitutes |
|-------------------------------------------------------------------|-----------------------------------|--------------------------------------------------------------------------------------------------|
| [`ObjectType`](#objecttype) | `std::map` | [`nlohmann::ordered_map`](../../api/ordered_map.md), Abseil hash maps |
| [`ArrayType`](#arraytype) | `std::vector` | `#!cpp std::deque` |
| [`StringType`](#stringtype) | `std::string` | `std::string`-like types over `char` |
| [`BooleanType`](#booleantype) | `bool` | none worth using |
| [`NumberIntegerType`](#numberintegertype-and-numberunsignedtype) | `std::int64_t` | any signed integer type |
| [`NumberUnsignedType`](#numberintegertype-and-numberunsignedtype) | `std::uint64_t` | any unsigned integer type at least as wide as `NumberIntegerType`, or `NumberIntegerType` itself |
| [`NumberFloatType`](#numberfloattype) | `double` | `float` (`long double`: no binary formats) |
| [`AllocatorType`](#allocatortype) | `std::allocator` | stateless allocators |
| [`JSONSerializer`](#jsonserializer) | `adl_serializer` | serializers with the same interface |
| [`BinaryType`](#binarytype) | `#!cpp std::vector<std::uint8_t>` | `#!cpp std::vector<char>` |
| [`CustomBaseClass`](#custombaseclass) | `void` | any default-constructible class |
!!! warning "Third-party containers and incomplete types"
@@ -504,13 +504,14 @@ Both types are stored **directly** inside `basic_json`'s union.
### Always required
- `#!cpp std::is_integral` must be satisfied: `NumberIntegerType` must be a **signed** integer type,
`NumberUnsignedType` an **unsigned** integer type. Class types are not supported -- among others, the constructors
taking integer values are constrained on `#!cpp std::is_integral`.
`NumberUnsignedType` an **unsigned** integer type or the same type as `NumberIntegerType` (see
[below](#same-type-for-both)). Class types are not supported -- among others, the constructors taking integer values
are constrained on `#!cpp std::is_integral`.
- Trivially default-constructible, trivially copyable, and trivially destructible (union member).
- `#!cpp std::numeric_limits` must be specialized for both types.
- `NumberUnsignedType` must be able to represent the absolute value of every `NumberIntegerType` value; serialization
of negative numbers converts the value to `NumberUnsignedType`. A `#!cpp static_assert` requires it to be at least as
wide as `NumberIntegerType`, which is what that amounts to for the standard integer types.
- An unsigned `NumberUnsignedType` must be able to represent the absolute value of every `NumberIntegerType` value;
serialization of negative numbers converts the value to `NumberUnsignedType`. A `#!cpp static_assert` requires it to
be at least as wide as `NumberIntegerType`, which is what that amounts to for the standard integer types.
- Both types must fit into the internal 64-character number buffer used by
[`dump`](../../api/basic_json/dump.md), which is the case for all standard integer types.
- [`std::hash<basic_json>`](../../api/basic_json/std_hash.md) additionally requires `#!cpp std::hash` specializations.
@@ -522,6 +523,23 @@ is stored as [`number_float_t`](../../api/basic_json/number_float_t.md) instead.
therefore silently changes parse results rather than raising an error. See
[Number Handling](number_handling.md) for details.
#### Same type for both
`NumberUnsignedType` may be the same type as `NumberIntegerType`, e.g.
`#!cpp nlohmann::json::with_integers_t<std::int64_t, std::int64_t>` (see
[`with_integers_t`](../../api/basic_json/with_t.md)), for code that only wants to handle one integer type. Such a `basic_json` stores every integer as
[`number_integer_t`](../../api/basic_json/number_integer_t.md):
- [`is_number_unsigned()`](../../api/basic_json/is_number_unsigned.md) is always `#!cpp false`, and
[`type()`](../../api/basic_json/type.md) never returns `value_t::number_unsigned`. Constructing a value from
`value_t::number_unsigned` gives a `value_t::number_integer` value.
- Values of unsigned C++ types (e.g., `#!cpp 5u`) are converted to `NumberIntegerType`, so values above its maximum
wrap around, as values outside the range of a narrower `NumberIntegerType` already do.
- The parsers store a non-negative integer above the maximum of `NumberIntegerType` (e.g., `18446744073709551615` for
`#!cpp std::int64_t`) as [`number_float_t`](../../api/basic_json/number_float_t.md), like any other integer that does
not fit.
- Converting from a `basic_json` with distinct types turns its unsigned values into `number_integer_t` values.
### Compatible types
| Type pair | Support |
@@ -529,8 +547,9 @@ therefore silently changes parse results rather than raising an error. See
| `#!cpp std::int64_t` / `#!cpp std::uint64_t` (default) | full |
| `#!cpp std::int32_t` / `#!cpp std::uint32_t`, `#!cpp long long` / `#!cpp unsigned long long` | full; narrower types change which literals the parser can represent |
| any other pair of standard signed/unsigned integer types | full |
| the same signed integer type for both, e.g. `#!cpp std::int64_t` / `#!cpp std::int64_t` | full; every integer is stored as `number_integer_t`, see [above](#same-type-for-both) |
| class types, enumerations | not usable; `#!cpp std::is_integral` must hold |
| `#!cpp bool`, or a type already used for another member of the union | not usable; `#!cpp std::is_integral<bool>` is in fact `#!cpp true`, but the `get_impl_ptr` overloads for `boolean_t`, `number_integer_t`, `number_unsigned_t` and `number_float_t` would collide |
| `#!cpp bool`, `number_float_t`, or the type of another member of the union | not usable; `#!cpp std::is_integral<bool>` is in fact `#!cpp true`, but the `get_impl_ptr` overloads for `boolean_t`, `number_integer_t`, `number_unsigned_t` and `number_float_t` would collide |
## `NumberFloatType`
docs/mkdocs/docs/home/architecture.md
+7 -5
View File
@@ -64,7 +64,7 @@ below are relative to `include/nlohmann`.
|-----------|----------|
| Value type enumeration | [`detail/value_t.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/value_t.hpp) |
| Input adapters | [`detail/input/input_adapters.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/input_adapters.hpp) |
| Lexer | [`detail/input/lexer.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/lexer.hpp), [`detail/input/number_parse.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/number_parse.hpp), [`detail/input/string_scan.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/string_scan.hpp) |
| Lexer | [`detail/input/lexer.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/lexer.hpp), [`detail/input/number_parse.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/number_parse.hpp), [`detail/input/string_scan.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/string_scan.hpp), [`detail/input/simd_scan.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/simd_scan.hpp) |
| Parser | [`detail/input/parser.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/parser.hpp) |
| SAX interface and DOM builders | [`detail/input/json_sax.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/json_sax.hpp) |
| Binary format readers | [`detail/input/binary_reader.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/input/binary_reader.hpp) |
@@ -194,9 +194,9 @@ packet-beta
| Bytes | Field | Type | Contents |
|-------|---------|------------|-------------------------------------------------------------------------------------------------------------------------------|
| 0 | `kind` | `uint8_t` | the type, numbered as [`value_t`](../api/basic_json/value_t.md): 0 null, 1 object, 2 array, 3 string, 4 boolean, 5 signed integer, 6 unsigned integer, 7 float; 10 for a link (see below) |
| 1 | `flags` | `uint8_t` | bits 0-1: where a string's bytes (or a number's token) are (0: the source text, 1: the buffer of decoded strings, for strings with escapes, 2: the edit buffer); bit 2: the value of a boolean; bits 3 and 4: moved and new (see below) |
| 2-3 | `extra` | `uint16_t` | numbers: the number of integer digits (low byte) and fraction digits (high byte), 255 for more; objects: the number of their hash index (1-based), or 0; otherwise 0 |
| 0 | `kind` | `uint8_t` | the type, numbered as [`value_t`](../api/basic_json/value_t.md): 0 null, 1 object, 2 array, 3 string, 4 boolean, 5 signed integer, 6 unsigned integer, 7 float; 10 for a link (see below). There is no node for a discarded value: a [discarded](../api/basic_json_view/is_discarded.md) view has none |
| 1 | `flags` | `uint8_t` | bits 0-1: where a string's bytes (or a number's token) are (0: the source text, 1: the buffer of decoded strings, for strings with escapes, 2: the edit buffer); bit 2: the value of a boolean; bit 3: moved, bit 4: new, bit 5: linked (see below) |
| 2-3 | `extra` | `uint16_t` | numbers: the number of integer digits (low byte) and fraction digits (high byte), 255 for more; objects: the number of their key hash index (1-based), or 0; otherwise 0 |
| 4-7 | `off` | `uint32_t` | where the value starts: the first byte after a string's opening quote (or its position in the buffer of decoded strings), the first byte of a number or literal, the bracket of an array or object |
| 8-11 | `len` | `uint32_t` | strings: the length after decoding; floats and literals: the length of the token; arrays and objects: the number of elements |
| 12-15 | `next` | `uint32_t` | arrays and objects: the number of nodes of the subtree, including the node itself |
@@ -212,7 +212,7 @@ packet-beta
step from element to element this way and skip whole subtrees in constant time.
- **Offsets** are 32 bits wide, so a document is limited to 4294967279 bytes, 4 GiB minus 16 bytes (a margin below
2^32 for positions one scanner step past the end of the text; `out_of_range.416`).
- **Large objects** (128 members or more) get a hash index after parsing
- **Large objects** (128 members or more) get a hash index for their keys after parsing
([`detail/view/object_index.hpp`](https://github.com/nlohmann/json/blob/develop/include/nlohmann/detail/view/object_index.hpp)):
an open-addressing table whose slots hold the distance from the object's node to a key's node, so that a lookup does
not compare every key. Of duplicate keys the table leads to the first, as a linear search does. The object's `extra`
@@ -257,6 +257,8 @@ edited:
sequence (a header node, then the entries), whose number is in `off`. The entries are links (`kind` 10), whose bytes
8-15 hold the address of the value's node, so values never move.
- A node written by an edit gets the flag *new* (bit 4): it has no position in the source text.
- A value that an entry of such a sequence links to gets the flag *linked* (bit 5): its extent in the parsed layout
(`next`) no longer matters, so a scalar can replace an array or object there in place.
- Views of read-only documents compile without any of this: how views walk the index is a template parameter
(`navigation<Editable>`).
docs/mkdocs/docs/home/exceptions.md
+20 -4
View File
@@ -972,9 +972,19 @@ double-precision number when `number_float_t` is `#!cpp float`.
### json.exception.out_of_range.407
An unsigned integer number greater than 9223372036854775807 cannot be represented in the binary format. This exception
is only thrown by [`to_bon8`](../api/basic_json/to_bon8.md), as [BON8](../features/binary_formats/bon8.md) has no
unsigned 64-bit integer type.
An integer number cannot be represented by the binary format it is serialized to:
- [BON8](../features/binary_formats/bon8.md) only stores integers that fit into int64, so
[`to_bon8`](../api/basic_json/to_bon8.md) throws for unsigned integers greater than 9223372036854775807.
- [CBOR](../features/binary_formats/cbor.md), [MessagePack](../features/binary_formats/messagepack.md), and
[BSON](../features/binary_formats/bson.md) store integers in at most 64 bits. With the default number types, every
integer fits, but a [`number_integer_t`](../api/basic_json/number_integer_t.md) or
[`number_unsigned_t`](../api/basic_json/number_unsigned_t.md) wider than 64 bits (e.g., `__int128`) can hold values
outside the range of the format: [-2^64, 2^64-1] for CBOR, [-2^63, 2^64-1] for MessagePack, and the range of int64
(signed integers) or uint64 (unsigned integers) for BSON.
[UBJSON](../features/binary_formats/ubjson.md) and [BJData](../features/binary_formats/bjdata.md) never throw this
exception, because they serialize integers beyond 64 bits as high-precision numbers.
!!! note "Former occurrences"
@@ -983,11 +993,17 @@ unsigned 64-bit integer type.
- Since version 3.9.0, integer numbers beyond int64 are serialized as high-precision UBJSON numbers.
- Since version 3.12.0, integer numbers beyond int64 are serialized as uint64 BSON numbers.
!!! failure "Example message"
Before version 3.13.0, CBOR, MessagePack, and BSON silently truncated integers wider than 64 bits, and BJData
truncated unsigned integers wider than 64 bits.
!!! failure "Example messages"
```
integer number 18446744073709551615 cannot be represented by BON8 as it does not fit int64
```
```
integer number 1267650600228229401496703205376 cannot be represented by CBOR as it does not fit [-2^64, 2^64-1]
```
### json.exception.out_of_range.408
docs/mkdocs/docs/home/releases.md
+9
View File
@@ -9,6 +9,15 @@ published on the [GitHub releases page](https://github.com/nlohmann/json/release
This documentation is built from the `develop` branch and may describe changes that are not part of a release
yet. Their version numbers are followed by an <span class="unreleased-version">unreleased</span> badge.
## Unreleased
- Converting an rvalue container to JSON (`json j = std::move(vec);`, `json j = std::map<std::string, std::string>{...};`)
now **moves** the elements instead of copying them (e.g., `std::vector<std::string>` with 100,000 strings: 4.7 ms to
2.3 ms). Two consequences: the source container is left in a valid but unspecified (moved-from) state, and if an
exception is thrown during the conversion, the source may be partially moved-from, so the strong exception guarantee
no longer holds for the source of an rvalue conversion (the JSON value itself is unaffected). Lvalues and `const`
objects are still copied. See [`basic_json`](../api/basic_json/basic_json.md).
## v3.12.0 (2025-04-11)
Fixes bugs found in 3.11.3 and adds several features. All changes are backward-compatible.
docs/mkdocs/mkdocs.yml
+3
View File
@@ -370,7 +370,9 @@ nav:
- 'JSON_DELETE_DEPRECATED_FUNCTIONS': api/macros/json_delete_deprecated_functions.md
- 'JSON_DIAGNOSTIC_POSITIONS': api/macros/json_diagnostic_positions.md
- 'JSON_DISABLE_ENUM_SERIALIZATION': api/macros/json_disable_enum_serialization.md
- 'JSON_DISABLE_STREAM_BULK_SCAN': api/macros/json_disable_stream_bulk_scan.md
- 'JSON_DISABLE_TUPLE_REFERENCE_CONVERSION': api/macros/json_disable_tuple_reference_conversion.md
- 'JSON_DISABLE_UNLOCKED_FILE_IO': api/macros/json_disable_unlocked_file_io.md
- 'JSON_HAS_CPP_11, JSON_HAS_CPP_14, JSON_HAS_CPP_17, JSON_HAS_CPP_20, JSON_HAS_CPP_23, JSON_HAS_CPP_26': api/macros/json_has_cpp_11.md
- 'JSON_HAS_EXPERIMENTAL_FILESYSTEM, JSON_HAS_FILESYSTEM': api/macros/json_has_filesystem.md
- 'JSON_HAS_RANGE_VIEW_CONVERSION': api/macros/json_has_range_view_conversion.md
@@ -381,6 +383,7 @@ nav:
- 'JSON_NO_AUTOMATIC_UDLS': api/macros/json_no_automatic_udls.md
- 'JSON_NOEXCEPTION': api/macros/json_noexception.md
- 'JSON_NO_IO': api/macros/json_no_io.md
- 'JSON_NO_SIMD': api/macros/json_no_simd.md
- 'JSON_NO_THREAD_LOCAL': api/macros/json_no_thread_local.md
- 'JSON_PRECISE_STREAM_POSITION': api/macros/json_precise_stream_position.md
- 'JSON_SKIP_LIBRARY_VERSION_CHECK': api/macros/json_skip_library_version_check.md
include/nlohmann/detail/abi_macros.hpp
+40 -4
View File
@@ -54,6 +54,14 @@
#define JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS 0
#endif
#ifndef JSON_DISABLE_STREAM_BULK_SCAN
#define JSON_DISABLE_STREAM_BULK_SCAN 0
#endif
#ifndef JSON_DISABLE_UNLOCKED_FILE_IO
#define JSON_DISABLE_UNLOCKED_FILE_IO 0
#endif
#if JSON_DIAGNOSTICS
#define NLOHMANN_JSON_ABI_TAG_DIAGNOSTICS _diag
#else
@@ -102,14 +110,38 @@
#define NLOHMANN_JSON_ABI_TAG_OBJECTS_FOR_ENUM_KEYED_MAPS
#endif
#if JSON_DISABLE_STREAM_BULK_SCAN
#define NLOHMANN_JSON_ABI_TAG_DISABLE_STREAM_BULK_SCAN _dsbs
#else
#define NLOHMANN_JSON_ABI_TAG_DISABLE_STREAM_BULK_SCAN
#endif
#if JSON_DISABLE_UNLOCKED_FILE_IO
#define NLOHMANN_JSON_ABI_TAG_DISABLE_UNLOCKED_FILE_IO _dufio
#else
#define NLOHMANN_JSON_ABI_TAG_DISABLE_UNLOCKED_FILE_IO
#endif
#ifdef JSON_VIEW_NO_SIMD
#define NLOHMANN_JSON_ABI_TAG_VIEW_NO_SIMD _vns
#else
#define NLOHMANN_JSON_ABI_TAG_VIEW_NO_SIMD
#endif
#ifdef JSON_VIEW_USE_SSSE3
#define NLOHMANN_JSON_ABI_TAG_VIEW_USE_SSSE3 _vssse3
#else
#define NLOHMANN_JSON_ABI_TAG_VIEW_USE_SSSE3
#endif
#ifndef NLOHMANN_JSON_NAMESPACE_NO_VERSION
#define NLOHMANN_JSON_NAMESPACE_NO_VERSION 0
#endif
// Construct the namespace ABI tags component
#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g, h) json_abi ## a ## b ## c ## d ## e ## f ## g ## h
#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e, f, g, h) \
NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g, h)
#define NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g, h, i, j, k, l) json_abi ## a ## b ## c ## d ## e ## f ## g ## h ## i ## j ## k ## l
#define NLOHMANN_JSON_ABI_TAGS_CONCAT(a, b, c, d, e, f, g, h, i, j, k, l) \
NLOHMANN_JSON_ABI_TAGS_CONCAT_EX(a, b, c, d, e, f, g, h, i, j, k, l)
#define NLOHMANN_JSON_ABI_TAGS \
NLOHMANN_JSON_ABI_TAGS_CONCAT( \
@@ -120,7 +152,11 @@
NLOHMANN_JSON_ABI_TAG_PRECISE_STREAM_POSITION, \
NLOHMANN_JSON_ABI_TAG_STRICT_NUL_HANDLING, \
NLOHMANN_JSON_ABI_TAG_STRICT_BINARY_UTF8, \
NLOHMANN_JSON_ABI_TAG_OBJECTS_FOR_ENUM_KEYED_MAPS)
NLOHMANN_JSON_ABI_TAG_OBJECTS_FOR_ENUM_KEYED_MAPS, \
NLOHMANN_JSON_ABI_TAG_DISABLE_STREAM_BULK_SCAN, \
NLOHMANN_JSON_ABI_TAG_DISABLE_UNLOCKED_FILE_IO, \
NLOHMANN_JSON_ABI_TAG_VIEW_NO_SIMD, \
NLOHMANN_JSON_ABI_TAG_VIEW_USE_SSSE3)
// Construct the namespace version component
#define NLOHMANN_JSON_NAMESPACE_VERSION_CONCAT_EX(major, minor, patch) \
include/nlohmann/detail/conversions/from_json.hpp
+50 -11
View File
@@ -80,7 +80,11 @@ void get_arithmetic_value(const BasicJsonType& j, ArithmeticType& val)
{
case value_t::number_unsigned:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
// never null: a basic_json whose number_unsigned_t is number_integer_t
// stores no number_unsigned values (#2573)
const auto* ptr = j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>();
JSON_ASSERT(ptr != nullptr);
val = static_cast<ArithmeticType>(*ptr);
break;
}
case value_t::number_integer:
@@ -150,7 +154,7 @@ inline void from_json(const BasicJsonType& j, typename BasicJsonType::number_flo
}
template<typename BasicJsonType>
inline void from_json(const BasicJsonType& j, typename BasicJsonType::number_unsigned_t& val)
inline void from_json(const BasicJsonType& j, number_unsigned_overload_t<BasicJsonType>& val)
{
get_arithmetic_value(j, val);
}
@@ -266,6 +270,22 @@ template<typename ConstructibleArrayType>
void from_json_array_reserve(ConstructibleArrayType& /*arr*/, std::size_t /*size*/, priority_tag<0> /*unused*/)
{}
// append through push_back() where available; containers without it (such as
// std::set) fall back to insert(end(), ...), which is what std::inserter did
template<typename ConstructibleArrayType, typename ValueType>
auto from_json_array_append(ConstructibleArrayType& arr, ValueType&& value, priority_tag<1> /*unused*/)
-> decltype(arr.push_back(std::forward<ValueType>(value)), void())
{
arr.push_back(std::forward<ValueType>(value));
}
template<typename ConstructibleArrayType, typename ValueType>
void from_json_array_append(ConstructibleArrayType& arr, ValueType&& value, priority_tag<0> /*unused*/)
{
using std::end;
arr.insert(end(arr), std::forward<ValueType>(value));
}
template<typename BasicJsonType, typename ConstructibleArrayType,
enable_if_t<
std::is_assignable<ConstructibleArrayType&, ConstructibleArrayType>::value,
@@ -275,17 +295,15 @@ auto from_json_array_impl(const BasicJsonType& j, ConstructibleArrayType& arr, p
j.template get<typename ConstructibleArrayType::value_type>(),
void())
{
using std::end;
ConstructibleArrayType ret;
from_json_array_reserve(ret, j.size(), priority_tag<1> {});
std::transform(j.begin(), j.end(),
std::inserter(ret, end(ret)), [](const BasicJsonType & i)
const auto* inner_array = j.template get_ptr<const typename BasicJsonType::array_t*>();
from_json_array_reserve(ret, inner_array->size(), priority_tag<1> {});
for (const auto& elem : *inner_array)
{
// get<BasicJsonType>() returns *this, this won't call a from_json
// method when value_type is BasicJsonType
return i.template get<typename ConstructibleArrayType::value_type>();
});
from_json_array_append(ret, elem.template get<typename ConstructibleArrayType::value_type>(), priority_tag<1> {});
}
arr = std::move(ret);
}
@@ -371,6 +389,23 @@ template<typename ConstructibleObjectType>
inline void from_json_object_reserve(ConstructibleObjectType& /*obj*/, std::size_t /*size*/, priority_tag<0> /*unused*/)
{}
// the keys of the source are sorted for the usual object types, so hinting the
// end makes every insertion constant-time (for containers that order their keys
// the same way); containers without emplace_hint() (such as ordered_map) fall
// back to emplace()
template<typename ConstructibleObjectType, typename Key, typename Value>
auto from_json_object_emplace(ConstructibleObjectType& obj, Key&& key, Value&& value, priority_tag<1> /*unused*/)
-> decltype(obj.emplace_hint(obj.end(), std::forward<Key>(key), std::forward<Value>(value)), void())
{
obj.emplace_hint(obj.end(), std::forward<Key>(key), std::forward<Value>(value));
}
template<typename ConstructibleObjectType, typename Key, typename Value>
void from_json_object_emplace(ConstructibleObjectType& obj, Key&& key, Value&& value, priority_tag<0> /*unused*/)
{
obj.emplace(std::forward<Key>(key), std::forward<Value>(value));
}
template<typename BasicJsonType, typename ConstructibleObjectType,
enable_if_t<is_constructible_object_type<BasicJsonType, ConstructibleObjectType>::value, int> = 0>
inline void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)
@@ -385,7 +420,7 @@ inline void from_json(const BasicJsonType& j, ConstructibleObjectType& obj)
from_json_object_reserve(ret, inner_object->size(), priority_tag<1> {});
for (const auto& p : *inner_object)
{
ret.emplace(p.first, p.second.template get<typename ConstructibleObjectType::mapped_type>());
from_json_object_emplace(ret, p.first, p.second.template get<typename ConstructibleObjectType::mapped_type>(), priority_tag<1> {});
}
obj = std::move(ret);
}
@@ -406,7 +441,11 @@ inline void from_json(const BasicJsonType& j, ArithmeticType& val)
{
case value_t::number_unsigned:
{
val = static_cast<ArithmeticType>(*j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>());
// never null: a basic_json whose number_unsigned_t is number_integer_t
// stores no number_unsigned values (#2573)
const auto* ptr = j.template get_ptr<const typename BasicJsonType::number_unsigned_t*>();
JSON_ASSERT(ptr != nullptr);
val = static_cast<ArithmeticType>(*ptr);
break;
}
case value_t::number_integer:
include/nlohmann/detail/conversions/to_chars.hpp
+29 -11
View File
@@ -23,12 +23,12 @@
#endif
// SSE2 (every x86-64 CPU) and NEON (every 64-bit Arm CPU) convert the 16
// digits of a double at once
#if defined(__x86_64__) || (defined(_M_X64) && !defined(_M_ARM64EC))
// digits of a double at once (unless JSON_NO_SIMD selects the portable code)
#if !defined(JSON_NO_SIMD) && (defined(__x86_64__) || (defined(_M_X64) && !defined(_M_ARM64EC)))
#include <emmintrin.h>
#define JSON_DTOA_SSE2 1
#define JSON_DTOA_NEON 0
#elif (defined(__aarch64__) || defined(_M_ARM64)) && !defined(_M_ARM64EC) && !defined(__ARM_BIG_ENDIAN)
#elif !defined(JSON_NO_SIMD) && (defined(__aarch64__) || defined(_M_ARM64)) && !defined(_M_ARM64EC) && !defined(__ARM_BIG_ENDIAN)
#include <arm_neon.h>
#define JSON_DTOA_SSE2 0
#define JSON_DTOA_NEON 1
@@ -1342,14 +1342,32 @@ inline char* write_shortest(char* first, const zmij::shortest_decimal d) noexcep
return end + (three ? 5 : 4);
}
/// the powers of ten up to 10^16
inline const std::array<std::uint64_t, 17>& powers_of_ten_16() noexcept
/// the powers of ten up to 10^19 (all that fit in std::uint64_t)
inline const std::array<std::uint64_t, 20>& powers_of_ten() noexcept
{
static const std::array<std::uint64_t, 17> powers =
static const std::array<std::uint64_t, 20> powers =
{
{
1u, 10u, 100u, 1000u, 10000u, 100000u, 1000000u, 10000000u, 100000000u, 1000000000u, 10000000000u,
100000000000u, 1000000000000u, 10000000000000u, 100000000000000u, 1000000000000000u, 10000000000000000u
1u,
10u,
100u,
1000u,
10000u,
100000u,
1000000u,
10000000u,
100000000u,
1000000000u,
10000000000u,
100000000000u,
1000000000000u,
10000000000000u,
100000000000000u,
1000000000000000u,
10000000000000000u,
100000000000000000u,
1000000000000000000u,
10000000000000000000u
}
};
return powers;
@@ -1367,9 +1385,9 @@ JSON_HEDLEY_NON_NULL(1)
JSON_HEDLEY_RETURNS_NON_NULL
inline char* write_short_decimal(char* first, std::uint64_t digits, int count, int exp) noexcept
{
JSON_ASSERT(digits >= powers_of_ten_16()[static_cast<std::size_t>(count - 1)] && count <= 15);
JSON_ASSERT(digits >= powers_of_ten()[static_cast<std::size_t>(count - 1)] && count <= 15);
const int scale = 16 - count;
return write_shortest(first, zmij::shortest_decimal{digits * powers_of_ten_16()[static_cast<std::size_t>(scale)], exp - scale - 1, 0, false});
return write_shortest(first, zmij::shortest_decimal{digits * powers_of_ten()[static_cast<std::size_t>(scale)], exp - scale - 1, 0, false});
}
/// as write_short_decimal(), counting the digits (not 0, less than 10^15)
@@ -1380,7 +1398,7 @@ inline char* write_short_decimal(char* first, std::uint64_t digits, int exp) noe
JSON_ASSERT(digits != 0 && digits < 1000000000000000u);
// floor(log10(2^bits)) + 1 digits, or one less
const int log2_bound = ((64 - count_leading_zeros(digits)) * 1233) >> 12;
const int count = log2_bound + (digits >= powers_of_ten_16()[static_cast<std::size_t>(log2_bound)] ? 1 : 0);
const int count = log2_bound + (digits >= powers_of_ten()[static_cast<std::size_t>(log2_bound)] ? 1 : 0);
return write_short_decimal(first, digits, count, exp);
}
include/nlohmann/detail/conversions/to_json.hpp
+127 -3
View File
@@ -13,7 +13,7 @@
#include <optional> // optional
#endif
#include <iterator> // begin, end
#include <iterator> // begin, end, make_move_iterator, move_iterator
#include <memory> // allocator_traits
#include <string> // basic_string, char_traits
#include <tuple> // tuple, get
@@ -48,6 +48,32 @@ namespace detail
* leave j with the type of the new value, but the pointer to the destroyed old one.
*/
// a move iterator over the elements of an rvalue container, unless they are
// const (e.g., std::set): libstdc++ before GCC 5 defines the reference of a
// std::move_iterator as value_type&&, which cannot bind to a const element
template<typename Iterator>
std::move_iterator<Iterator> make_move_iterator_if_mutable_impl(const Iterator& it, std::true_type /*mutable*/)
{
return std::make_move_iterator(it);
}
template<typename Iterator>
Iterator make_move_iterator_if_mutable_impl(const Iterator& it, std::false_type /*mutable*/)
{
return it;
}
template<typename Iterator>
using is_mutable_iterator = std::integral_constant < bool,
!std::is_const<typename std::remove_reference<decltype(*std::declval<Iterator&>())>::type>::value >;
template<typename Iterator>
auto make_move_iterator_if_mutable(const Iterator& it)
-> decltype(make_move_iterator_if_mutable_impl(it, is_mutable_iterator<Iterator> {}))
{
return make_move_iterator_if_mutable_impl(it, is_mutable_iterator<Iterator> {});
}
template<value_t> struct external_constructor;
template<>
@@ -167,6 +193,17 @@ struct external_constructor<value_t::array>
j.replace_value(value_t::array, value);
}
/// an rvalue container: move its elements
template<typename BasicJsonType, typename CompatibleArrayType>
static void construct_moving(BasicJsonType& j, CompatibleArrayType& arr)
{
using std::begin;
using std::end;
const typename BasicJsonType::json_value value(j.template create<typename BasicJsonType::array_t>(make_move_iterator_if_mutable(begin(arr)), make_move_iterator_if_mutable(end(arr))));
j.replace_value(value_t::array, value);
}
template<typename BasicJsonType>
static void construct(BasicJsonType& j, const std::vector<bool>& arr)
{
@@ -217,6 +254,17 @@ struct external_constructor<value_t::object>
j.replace_value(value_t::object, value);
}
/// an rvalue container: move its values
template<typename BasicJsonType, typename CompatibleObjectType>
static void construct_moving(BasicJsonType& j, CompatibleObjectType& obj)
{
using std::begin;
using std::end;
const typename BasicJsonType::json_value value(j.template create<typename BasicJsonType::object_t>(make_move_iterator_if_mutable(begin(obj)), make_move_iterator_if_mutable(end(obj))));
j.replace_value(value_t::object, value);
}
template < typename BasicJsonType, typename CompatibleObjectType,
enable_if_t < !std::is_same<CompatibleObjectType, typename BasicJsonType::object_t>::value, int > = 0 >
static void construct(BasicJsonType& j, const CompatibleObjectType& obj)
@@ -303,14 +351,14 @@ inline void to_json(BasicJsonType& j, FloatType val) noexcept
}
template<typename BasicJsonType, typename CompatibleNumberUnsignedType,
enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_unsigned_t, CompatibleNumberUnsignedType>::value, int> = 0>
enable_if_t<is_compatible_integer_type<number_unsigned_overload_t<BasicJsonType>, CompatibleNumberUnsignedType>::value, int> = 0>
inline void to_json(BasicJsonType& j, CompatibleNumberUnsignedType val) noexcept
{
external_constructor<value_t::number_unsigned>::construct(j, static_cast<typename BasicJsonType::number_unsigned_t>(val));
}
template<typename BasicJsonType, typename CompatibleNumberIntegerType,
enable_if_t<is_compatible_integer_type<typename BasicJsonType::number_integer_t, CompatibleNumberIntegerType>::value, int> = 0>
enable_if_t<is_compatible_number_integer_type<BasicJsonType, CompatibleNumberIntegerType>::value, int> = 0>
inline void to_json(BasicJsonType& j, CompatibleNumberIntegerType val) noexcept
{
external_constructor<value_t::number_integer>::construct(j, static_cast<typename BasicJsonType::number_integer_t>(val));
@@ -354,6 +402,68 @@ inline void to_json(BasicJsonType& j, const CompatibleArrayType& arr)
external_constructor<value_t::array>::construct(j, arr);
}
// types that have a dedicated to_json overload and must not be treated as generic containers
template<typename T>
struct has_dedicated_to_json : std::false_type {};
#if JSON_HAS_FILESYSTEM || JSON_HAS_EXPERIMENTAL_FILESYSTEM
template<>
struct has_dedicated_to_json<std_fs::path> : std::true_type {};
#endif
#if defined(__cpp_lib_char8_t)
template<typename Tr, typename Allocator>
struct has_dedicated_to_json<std::basic_string<char8_t, Tr, Allocator>> : std::true_type {};
#endif
#if JSON_HAS_RANGE_VIEW_CONVERSION
template<typename T>
struct is_range_view_type : is_compatible_range_view<T> {};
#else
template<typename T>
struct is_range_view_type : std::false_type {};
#endif
#if JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS
template<typename T>
struct is_enum_keyed_map_type : is_enum_keyed_map<T> {};
#else
template<typename T>
struct is_enum_keyed_map_type : std::false_type {};
#endif
// rvalue (non-const) container: the generic to_json takes its elements by move
template<typename T>
using is_movable_container_rvalue = negation<disjunction<
std::is_lvalue_reference<T>,
std::is_const<T>,
has_dedicated_to_json<T>,
is_basic_json<T>,
is_enum_keyed_map_type<T>,
std::is_same<T, std::vector<bool>>>>;
// rvalue array-like containers; object types are ruled out before views are
// checked, as std::ranges::view<T> for the object_t of an ordered_json would
// need that ordered_json to be complete (GCC 11, see #3312)
template<typename BasicJsonType, typename T>
using is_rvalue_array_to_json = conjunction<is_movable_container_rvalue<T>,
negation<is_compatible_object_type<BasicJsonType, T>>,
negation<is_range_view_type<T>>,
is_compatible_array_type<BasicJsonType, T>,
negation<disjunction<
std::is_same<T, typename BasicJsonType::array_t>,
std::is_same<T, typename BasicJsonType::binary_t>,
is_compatible_string_type<BasicJsonType, T>,
is_compatible_binary_type<BasicJsonType, T>>>>;
// rvalue containers: their elements are moved instead of copied
template<typename BasicJsonType, typename CompatibleArrayType,
enable_if_t<is_rvalue_array_to_json<BasicJsonType, CompatibleArrayType>::value, int> = 0>
inline void to_json(BasicJsonType& j, CompatibleArrayType && arr) // NOLINT(cppcoreguidelines-missing-std-forward)
{
external_constructor<value_t::array>::construct_moving(j, arr);
}
#if JSON_HAS_RANGE_VIEW_CONVERSION
template < typename BasicJsonType, typename T,
enable_if_t < is_compatible_range_view<std::remove_cvref_t<T>>::value
@@ -427,6 +537,20 @@ inline void to_json(BasicJsonType& j, const EnumKeyedMap& map)
}
#endif
// rvalue object-like containers (views have no key_type and mapped_type, so
// they are no compatible object type)
template<typename BasicJsonType, typename T>
using is_rvalue_object_to_json = conjunction<is_movable_container_rvalue<T>,
negation<std::is_same<T, typename BasicJsonType::object_t>>,
is_compatible_object_type<BasicJsonType, T>>;
template<typename BasicJsonType, typename CompatibleObjectType,
enable_if_t<is_rvalue_object_to_json<BasicJsonType, CompatibleObjectType>::value, int> = 0>
inline void to_json(BasicJsonType& j, CompatibleObjectType && obj) // NOLINT(cppcoreguidelines-missing-std-forward)
{
external_constructor<value_t::object>::construct_moving(j, obj);
}
template<typename BasicJsonType>
inline void to_json(BasicJsonType& j, typename BasicJsonType::object_t&& obj)
{
include/nlohmann/detail/conversions/zmij.hpp
+4 -1
View File
@@ -184,7 +184,10 @@ JSON_HEDLEY_ALWAYS_INLINE shortest_decimal to_shortest(std::uint64_t bits) noexc
const uint128_parts p10 = pow10(-dec_exp - 1);
const uint128_parts p = umul192_hi128(p10.high, p10.low, bin_sig << static_cast<unsigned>(shift));
std::uint64_t integral = p.high >> static_cast<unsigned>(extra_shift);
const std::uint64_t fractional = (p.high << static_cast<unsigned>(64 - extra_shift)) | (p.low >> static_cast<unsigned>(extra_shift));
// (no casts in the shifts: MSVC 2015 warns C4554 on them despite the parentheses)
constexpr auto fractional_low_shift = static_cast<unsigned>(extra_shift);
constexpr unsigned fractional_high_shift = 64u - fractional_low_shift;
const std::uint64_t fractional = (p.high << fractional_high_shift) | (p.low >> fractional_low_shift);
std::uint64_t digit = 0;
bool round_up = false;
bool round_down = false;
include/nlohmann/detail/exceptions.hpp
+72 -2
View File
@@ -428,7 +428,7 @@ void templated_json_throw(ExceptionType exception)
@throw type_error.302 always
*/
template<typename BasicJsonType>
JSON_HEDLEY_NO_RETURN inline void throw_type_must_be(const char* expected, const BasicJsonType& j)
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_type_must_be(const char* expected, const BasicJsonType& j)
{
static_cast<void>(expected); // unused when JSON_NOEXCEPTION is defined
static_cast<void>(j);
@@ -443,7 +443,7 @@ JSON_HEDLEY_NO_RETURN inline void throw_type_must_be(const char* expected, const
@throw type_error always
*/
template<typename BasicJsonType>
JSON_HEDLEY_NO_RETURN inline void throw_cannot_use_with(const exception_id id_, const char* operation, const BasicJsonType& j)
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_cannot_use_with(const exception_id id_, const char* operation, const BasicJsonType& j)
{
static_cast<void>(id_); // unused when JSON_NOEXCEPTION is defined
static_cast<void>(operation);
@@ -451,6 +451,76 @@ JSON_HEDLEY_NO_RETURN inline void throw_cannot_use_with(const exception_id id_,
JSON_THROW(type_error::create(id_, concat("cannot use ", operation, " with ", j.type_name()), &j));
}
/*!
@brief throws ExceptionType with a fixed message; kept out of line so that callers do not carry the exception construction
*/
template<typename ExceptionType, typename BasicJsonContext>
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_literal(const exception_id id_, const char* what_arg, BasicJsonContext context)
{
static_cast<void>(id_); // unused when JSON_NOEXCEPTION is defined
static_cast<void>(what_arg);
static_cast<void>(context);
JSON_THROW(ExceptionType::create(id_, what_arg, context));
}
// JSON Patch errors; constructed out of line so that patch_inplace() does not carry them
template<typename BasicJsonType>
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_patch_add_parent(const BasicJsonType& parent)
{
static_cast<void>(parent);
JSON_THROW(out_of_range::create(exception_id::patch_add_parent_not_container, concat("cannot add value: the JSON Patch 'add' target's parent is of type ", parent.type_name(), ", but must be an object or array"), &parent));
}
template<typename BasicJsonType>
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_patch_remove_parent(const BasicJsonType& parent)
{
static_cast<void>(parent);
JSON_THROW(out_of_range::create(exception_id::patch_remove_parent_not_container, concat("cannot remove value: the JSON Patch 'remove' target's parent is of type ", parent.type_name(), ", but must be an object or array"), &parent));
}
template<typename BasicJsonType>
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_patch_not_an_array(const BasicJsonType& j)
{
static_cast<void>(j);
JSON_THROW(parse_error::create(exception_id::patch_not_an_array, 0, "JSON patch must be an array of objects", &j));
}
template<typename StringType, typename BasicJsonType>
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_patch_missing_member(const StringType& op, const StringType& member, const bool string_type, const BasicJsonType& val)
{
static_cast<void>(op);
static_cast<void>(member);
static_cast<void>(string_type);
static_cast<void>(val);
// context-sensitive error message
JSON_THROW(parse_error::create(exception_id::patch_invalid_operation, 0, concat((op == "op") ? std::string("operation") : concat("operation '", op, '\''), string_type ? " must have string member '" : " must have member '", member, "'"), &val));
}
template<typename StringType, typename BasicJsonType>
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_patch_move_into_child(const StringType& from_path, const StringType& path, const BasicJsonType& result)
{
static_cast<void>(from_path);
static_cast<void>(path);
static_cast<void>(result);
JSON_THROW(out_of_range::create(exception_id::patch_move_into_child, concat("cannot move value: 'from' path '", from_path, "' is a proper prefix of 'path' '", path, "'"), &result));
}
template<typename BasicJsonType>
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_patch_test_failed(const BasicJsonType& val)
{
static_cast<void>(val);
JSON_THROW(other_error::create(exception_id::patch_test_failed, concat("unsuccessful: ", val.dump()), &val));
}
template<typename StringType, typename BasicJsonType>
JSON_HEDLEY_NO_RETURN JSON_HEDLEY_NEVER_INLINE void throw_patch_invalid_operation(const StringType& op, const BasicJsonType& val)
{
static_cast<void>(op);
static_cast<void>(val);
JSON_THROW(parse_error::create(exception_id::patch_invalid_operation, 0, concat("operation value '", op, "' is invalid"), &val));
}
} // namespace detail
NLOHMANN_JSON_NAMESPACE_END
include/nlohmann/detail/input/binary_reader.hpp
+89 -33
View File
@@ -195,7 +195,7 @@ class binary_reader
if (JSON_HEDLEY_UNLIKELY(current != char_traits<char_type>::eof()))
{
return last_byte_error(exception_id::unexpected_end_of_input, concat("expected end of input; last byte: 0x", get_token_string()), "value");
return last_byte_error(exception_id::unexpected_end_of_input, "expected end of input", "value", "");
}
}
@@ -317,7 +317,7 @@ class binary_reader
{
if (JSON_HEDLEY_UNLIKELY(document_size < 0 || static_cast<std::size_t>(document_size) != chars_read - document_start))
{
return last_byte_error(exception_id::unexpected_byte, concat("document size ", std::to_string(document_size), " does not match the number of bytes read (", std::to_string(chars_read - document_start), ")"), "document");
return bson_document_size_error(document_size, chars_read - document_start);
}
return true;
}
@@ -509,7 +509,7 @@ class binary_reader
{
if (JSON_HEDLEY_UNLIKELY(len < 1))
{
return last_byte_error(exception_id::unexpected_byte, concat("string length must be at least 1, is ", std::to_string(len)), "string");
return bson_length_error("string length must be at least 1, is ", len, "string");
}
if (JSON_HEDLEY_UNLIKELY(!get_string(len - static_cast<NumberType>(1), result)))
@@ -539,7 +539,7 @@ class binary_reader
{
if (JSON_HEDLEY_UNLIKELY(len < 0))
{
return last_byte_error(exception_id::unexpected_byte, concat("byte array length cannot be negative, is ", std::to_string(len)), "binary");
return bson_length_error("byte array length cannot be negative, is ", len, "binary");
}
// All BSON binary values have a subtype
@@ -629,9 +629,7 @@ class binary_reader
default: // anything else is not supported (yet)
{
const std::string cr_str = hex_byte(static_cast<std::uint8_t>(element_type));
return sax->parse_error(element_type_parse_position, cr_str,
parse_error::create(exception_id::bson_unsupported_type, element_type_parse_position, concat("Unsupported BSON record type 0x", cr_str), nullptr));
return bson_unsupported_type_error(element_type_parse_position, element_type);
}
}
}
@@ -1060,6 +1058,7 @@ class binary_reader
@param[in] context parsing context for the error message
@return whether the SAX consumer accepts the parse error
*/
JSON_HEDLEY_NEVER_INLINE
bool cbor_indefinite_string_error(const char* type_name, const char* context)
{
return last_byte_error(exception_id::invalid_string_or_size, concat("indefinite-length ", type_name, " is not allowed inside indefinite-length ", type_name, "; last byte: 0x", get_token_string()), context);
@@ -1139,7 +1138,7 @@ class binary_reader
default:
{
return last_byte_error(exception_id::invalid_string_or_size, concat("expected length specification (0x60-0x7B)", inside_indefinite ? "" : " or indefinite string type (0x7F)", "; last byte: 0x", get_token_string()), "string");
return last_byte_error(exception_id::invalid_string_or_size, "expected length specification (0x60-0x7B)", "string", inside_indefinite ? "" : " or indefinite string type (0x7F)");
}
}
}
@@ -1269,7 +1268,7 @@ class binary_reader
break;
}
return last_byte_error(exception_id::invalid_string_or_size, concat("only string keys are supported, but found ", found, "; last byte: 0x", get_token_string()), "object key");
return last_byte_error(exception_id::invalid_string_or_size, "only string keys are supported, but found ", "object key", found);
}
/*!
@@ -1350,7 +1349,7 @@ class binary_reader
default:
{
return last_byte_error(exception_id::invalid_string_or_size, concat("expected length specification (0x40-0x5B)", inside_indefinite ? "" : " or indefinite binary array type (0x5F)", "; last byte: 0x", get_token_string()), "binary");
return last_byte_error(exception_id::invalid_string_or_size, "expected length specification (0x40-0x5B)", "binary", inside_indefinite ? "" : " or indefinite binary array type (0x5F)");
}
}
}
@@ -1496,8 +1495,7 @@ class binary_reader
{
if (JSON_HEDLEY_UNLIKELY(!value_in_range_of<std::size_t>(len) || len == detail::unknown_size()))
{
return sax->parse_error(chars_read, get_token_string(), out_of_range::create(exception_id::container_too_large,
exception_message(concat("excessive ", context, " size"), "size"), nullptr));
return container_size_error(context);
}
result = conditional_static_cast<std::size_t>(len);
return true;
@@ -2065,7 +2063,7 @@ class binary_reader
default:
{
return last_byte_error(exception_id::invalid_string_or_size, concat("expected length specification (0xA0-0xBF, 0xD9-0xDB); last byte: 0x", get_token_string()), "string");
return last_byte_error(exception_id::invalid_string_or_size, "expected length specification (0xA0-0xBF, 0xD9-0xDB)", "string", "");
}
}
}
@@ -2157,7 +2155,7 @@ class binary_reader
break;
}
return last_byte_error(exception_id::invalid_string_or_size, concat("only string keys are supported, but found ", found, "; last byte: 0x", get_token_string()), "object key");
return last_byte_error(exception_id::invalid_string_or_size, "only string keys are supported, but found ", "object key", found);
}
/*!
@@ -2655,8 +2653,7 @@ class binary_reader
}
if (JSON_HEDLEY_UNLIKELY(!value_in_range_of<std::size_t>(number)))
{
return sax->parse_error(chars_read, get_token_string(), out_of_range::create(exception_id::container_too_large,
exception_message("integer value overflow", "size"), nullptr));
return out_of_range_error(exception_id::container_too_large, "integer value overflow", "size");
}
result = static_cast<std::size_t>(number); // NOLINT(bugprone-signed-char-misuse,cert-str34-c): number is not a char
return true;
@@ -2753,8 +2750,7 @@ class binary_reader
}
if (!value_in_range_of<std::size_t>(number))
{
return sax->parse_error(chars_read, get_token_string(), out_of_range::create(exception_id::container_too_large,
exception_message("integer value overflow", "size"), nullptr));
return out_of_range_error(exception_id::container_too_large, "integer value overflow", "size");
}
result = detail::conditional_static_cast<std::size_t>(number);
return true;
@@ -2832,7 +2828,7 @@ class binary_reader
// or SIZE_MAX.
if (JSON_HEDLEY_UNLIKELY(result > (std::numeric_limits<std::size_t>::max)() / i))
{
return sax->parse_error(chars_read, get_token_string(), out_of_range::create(exception_id::container_too_large, exception_message("excessive ndarray size caused overflow", "size"), nullptr));
return out_of_range_error(exception_id::container_too_large, "excessive ndarray size caused overflow", "size");
}
result *= i;
// the pre-check above already rules out result becoming 0
@@ -2841,7 +2837,7 @@ class binary_reader
// unknown-size container (see get_ubjson_size_type())
if (result == npos)
{
return sax->parse_error(chars_read, get_token_string(), out_of_range::create(exception_id::container_too_large, exception_message("excessive ndarray size caused overflow", "size"), nullptr));
return out_of_range_error(exception_id::container_too_large, "excessive ndarray size caused overflow", "size");
}
if (JSON_HEDLEY_UNLIKELY(!emit_unsigned(i)))
{
@@ -2891,7 +2887,7 @@ class binary_reader
if (input_format == input_format_t::bjdata
&& JSON_HEDLEY_UNLIKELY(is_bjd_excluded_optimized_type(result.second)))
{
return last_byte_error(exception_id::unexpected_byte, concat("marker 0x", get_token_string(), " is not a permitted optimized array type"), "type");
return optimized_type_error();
}
if (JSON_HEDLEY_UNLIKELY(!unexpect_eof("type")))
@@ -2906,7 +2902,7 @@ class binary_reader
{
return false;
}
return last_byte_error(exception_id::unexpected_byte, concat("expected '#' after type information; last byte: 0x", get_token_string()), "size");
return last_byte_error(exception_id::unexpected_byte, "expected '#' after type information", "size", "");
}
const bool is_error = get_ubjson_size_value(result.first, is_ndarray, 0, result.second);
@@ -3057,7 +3053,7 @@ class binary_reader
}
if (JSON_HEDLEY_UNLIKELY(current > 127))
{
return last_byte_error(exception_id::invalid_string_or_size, concat("byte after 'C' must be in range 0x00..0x7F; last byte: 0x", get_token_string()), "char");
return last_byte_error(exception_id::invalid_string_or_size, "byte after 'C' must be in range 0x00..0x7F", "char", "");
}
string_t s(1, static_cast<typename string_t::value_type>(current));
return sax->string(s);
@@ -3141,8 +3137,7 @@ class binary_reader
if (JSON_HEDLEY_UNLIKELY((size_and_type.second == 'Z' || size_and_type.second == 'T' || size_and_type.second == 'F')
&& size_and_type.first > max_valueless_container_size))
{
return sax->parse_error(chars_read, get_token_string(), out_of_range::create(exception_id::container_too_large,
exception_message("excessive array size", "size"), nullptr));
return out_of_range_error(exception_id::container_too_large, "excessive array size", "size");
}
if (JSON_HEDLEY_UNLIKELY(!enter_array(size_and_type.first, size_and_type.second)))
@@ -3854,7 +3849,7 @@ class binary_reader
{
// in case of failure, advance position by 1 to report the failing location
++chars_read;
sax->parse_error(chars_read, "<end of file>", parse_error::create(exception_id::unexpected_end_of_input, chars_read, exception_message("unexpected end of input", context), nullptr));
static_cast<void>(report_eof(context));
return false;
}
return true;
@@ -4007,8 +4002,7 @@ class binary_reader
const auto result = static_cast<number_float_t>(number);
if (JSON_HEDLEY_UNLIKELY(std::isfinite(number) && !std::isfinite(result)))
{
return sax->parse_error(chars_read, get_token_string(),
out_of_range::create(exception_id::number_overflow, exception_message("number overflow", "value"), nullptr));
return out_of_range_error(exception_id::number_overflow, "number overflow", "value");
}
return sax->number_float(result, "");
}
@@ -4223,22 +4217,82 @@ class binary_reader
{
if (JSON_HEDLEY_UNLIKELY(current == char_traits<char_type>::eof()))
{
return sax->parse_error(chars_read, "<end of file>",
parse_error::create(exception_id::unexpected_end_of_input, chars_read, exception_message("unexpected end of input", context), nullptr));
return report_eof(context);
}
return true;
}
/*!
@brief reports an unexpected end of input (out of line to keep the exception
construction out of the hot reading functions)
@param[in] context further context information (for diagnostics)
@return the result of the SAX parser's parse_error()
*/
JSON_HEDLEY_NON_NULL(2)
JSON_HEDLEY_NEVER_INLINE
bool report_eof(const char* context) const
{
return sax->parse_error(chars_read, "<end of file>",
parse_error::create(exception_id::unexpected_end_of_input, chars_read, exception_message("unexpected end of input", context), nullptr));
}
/*!
@brief reports an out_of_range error at the last read byte (out of line)
*/
JSON_HEDLEY_NEVER_INLINE
bool out_of_range_error(const exception_id id_, const char* detail, const char* context) const
{
return sax->parse_error(chars_read, get_token_string(), out_of_range::create(id_, exception_message(detail, context), nullptr));
}
JSON_HEDLEY_NEVER_INLINE
bool container_size_error(const char* what) const
{
return sax->parse_error(chars_read, get_token_string(), out_of_range::create(exception_id::container_too_large,
exception_message(concat("excessive ", what, " size"), "size"), nullptr));
}
JSON_HEDLEY_NEVER_INLINE
bool optimized_type_error() const
{
return last_byte_error(exception_id::unexpected_byte, concat("marker 0x", get_token_string(), " is not a permitted optimized array type"), "type");
}
template<typename NumberType>
JSON_HEDLEY_NEVER_INLINE
bool bson_length_error(const char* prefix, const NumberType len, const char* context) const
{
return last_byte_error(exception_id::unexpected_byte, concat(prefix, std::to_string(len)), context);
}
JSON_HEDLEY_NEVER_INLINE
bool bson_document_size_error(const std::int32_t document_size, const std::size_t bytes_read) const
{
return last_byte_error(exception_id::unexpected_byte, concat("document size ", std::to_string(document_size), " does not match the number of bytes read (", std::to_string(bytes_read), ")"), "document");
}
JSON_HEDLEY_NEVER_INLINE
bool bson_unsupported_type_error(const std::size_t position, const char_int_type element_type) const
{
const std::string cr_str = hex_byte(static_cast<std::uint8_t>(element_type));
return sax->parse_error(position, cr_str,
parse_error::create(exception_id::bson_unsupported_type, position, concat("Unsupported BSON record type 0x", cr_str), nullptr));
}
/*!
@brief reports a parse error at the last read byte
@param[in] id_ the id of the parse_error exception
@param[in] detail a detailed error message
@param[in] context further context information
@param[in] tail optional text appended to the detail, followed by "; last byte: 0x<token>"
@return the result of the SAX parser's parse_error()
*/
bool last_byte_error(const exception_id id_, const std::string& detail, const std::string& context) const
JSON_HEDLEY_NEVER_INLINE
bool last_byte_error(const exception_id id_, const std::string& detail, const char* context, const char* tail = nullptr) const
{
return sax->parse_error(chars_read, get_token_string(), parse_error::create(id_, chars_read, exception_message(detail, context), nullptr));
// with a tail, the message reads "<detail><tail>; last byte: 0x<token>"
return sax->parse_error(chars_read, get_token_string(), parse_error::create(id_, chars_read,
exception_message(tail == nullptr ? detail : concat(detail, tail, "; last byte: 0x", get_token_string()), context), nullptr));
}
/*!
@@ -4247,7 +4301,8 @@ class binary_reader
@param[in] context further context information
@return the result of the SAX parser's parse_error()
*/
bool unexpected_byte(const char* detail, const std::string& context) const
JSON_HEDLEY_NEVER_INLINE
bool unexpected_byte(const char* detail, const char* context) const
{
return last_byte_error(exception_id::unexpected_byte, concat(detail, ": 0x", get_token_string()), context);
}
@@ -4258,6 +4313,7 @@ class binary_reader
@param[in] context further context information
@return the result of the SAX parser's parse_error()
*/
JSON_HEDLEY_NEVER_INLINE
bool length_type_error(const char* position, const char* context) const
{
const char* types = input_format == input_format_t::bjdata ? "U, i, u, I, m, l, M, L" : "U, i, I, l, L";
include/nlohmann/detail/input/input_adapters.hpp
+304 -11
View File
@@ -14,10 +14,12 @@
#include <cstdint> // uint32_t
#include <cstring> // strlen
#include <iterator> // begin, end, iterator_traits, random_access_iterator_tag, distance, next, reverse_iterator
#include <limits> // numeric_limits
#include <streambuf> // streambuf
#include <string> // string, char_traits
#include <type_traits> // enable_if, is_base_of, is_pointer, is_integral, remove_pointer
#include <utility> // pair, declval
#include <vector> // vector
#ifndef JSON_NO_IO
#include <cstdio> // FILE *
@@ -30,6 +32,33 @@
#include <nlohmann/detail/meta/type_traits.hpp>
#include <nlohmann/detail/string_utils.hpp>
#ifndef JSON_NO_IO
// Which unlocked stdio functions file_input_adapter uses (see
// JSON_DISABLE_UNLOCKED_FILE_IO): 1 = POSIX flockfile/getc_unlocked,
// 2 = Microsoft CRT _lock_file/_fgetc_nolock, 0 = none (std::fgetc, which
// locks the file for every character). Only C libraries known to declare
// the functions are listed; the macros are tested after <cstdio>, which
// defines __GLIBC__. MemorySanitizer builds always use std::fgetc: glibc's
// inline getc_unlocked reads the stdio buffer directly, which glibc (not
// instrumented) filled, so MemorySanitizer would report a false positive.
#if defined(__has_feature)
#if __has_feature(memory_sanitizer)
#define JSON_UNLOCKED_FILE_IO_MSAN 1
#endif
#endif
#if JSON_DISABLE_UNLOCKED_FILE_IO || defined(JSON_UNLOCKED_FILE_IO_MSAN)
#define JSON_UNLOCKED_FILE_IO 0
#elif defined(_MSC_VER)
#define JSON_UNLOCKED_FILE_IO 2
#elif defined(__GLIBC__) || defined(__APPLE__) || defined(__ANDROID__) || defined(__FreeBSD__) || defined(__NetBSD__) || defined(__OpenBSD__) || defined(__DragonFly__)
#define JSON_UNLOCKED_FILE_IO 1
#else
#define JSON_UNLOCKED_FILE_IO 0
#endif
#undef JSON_UNLOCKED_FILE_IO_MSAN
#endif // JSON_NO_IO
NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
{
@@ -56,18 +85,35 @@ class file_input_adapter
: m_file(f)
{
JSON_ASSERT(m_file != nullptr);
lock();
}
// make class move-only
file_input_adapter(const file_input_adapter&) = delete;
file_input_adapter(file_input_adapter&&) noexcept = default;
file_input_adapter(file_input_adapter&& rhs) noexcept
: m_file(rhs.m_file)
{
// the lock is owned by the thread, not the adapter: hand it over
rhs.m_file = nullptr;
}
file_input_adapter& operator=(const file_input_adapter&) = delete;
file_input_adapter& operator=(file_input_adapter&&) = delete;
~file_input_adapter() = default;
~file_input_adapter()
{
unlock();
}
std::char_traits<char>::int_type get_character() noexcept
{
// the file is locked for the lifetime of the adapter, so the
// per-character lock of std::fgetc can be skipped
#if JSON_UNLOCKED_FILE_IO == 1
return getc_unlocked(m_file);
#elif JSON_UNLOCKED_FILE_IO == 2
return _fgetc_nolock(m_file);
#else
return std::fgetc(m_file);
#endif
}
// returns the number of characters successfully read
@@ -78,6 +124,32 @@ class file_input_adapter
}
private:
// Lock the file once for the whole parse instead of once per character.
// The lock is recursive, so fread() and the user's own stdio calls on the
// same thread keep working.
void lock() noexcept
{
#if JSON_UNLOCKED_FILE_IO == 1
flockfile(m_file);
#elif JSON_UNLOCKED_FILE_IO == 2
_lock_file(m_file);
#endif
}
void unlock() noexcept
{
// a moved-from adapter has no file and holds no lock
if (m_file == nullptr)
{
return;
}
#if JSON_UNLOCKED_FILE_IO == 1
funlockfile(m_file);
#elif JSON_UNLOCKED_FILE_IO == 2
_unlock_file(m_file);
#endif
}
/// the file pointer to read from
std::FILE* m_file;
};
@@ -127,15 +199,26 @@ class input_stream_adapter
input_stream_adapter& operator=(input_stream_adapter&) = delete;
input_stream_adapter& operator=(input_stream_adapter&&) = delete;
#if JSON_PRECISE_STREAM_POSITION
input_stream_adapter(input_stream_adapter&& rhs) noexcept
: is(rhs.is), sb(rhs.sb), lookahead(rhs.lookahead)
: is(rhs.is), sb(rhs.sb)
#if JSON_PRECISE_STREAM_POSITION
, lookahead(rhs.lookahead)
#endif
#if !JSON_DISABLE_STREAM_BULK_SCAN
, token_carry(std::move(rhs.token_carry))
, token_segment(rhs.token_segment)
, current_in_get_area(rhs.current_in_get_area)
, tracking_token(rhs.tracking_token)
#endif
{
rhs.is = nullptr;
rhs.sb = nullptr;
#if JSON_PRECISE_STREAM_POSITION
rhs.lookahead = false;
#endif
}
#if JSON_PRECISE_STREAM_POSITION
// Whether the character last returned by get_character() can be given back
// to the input with release_lookahead().
static constexpr bool supports_lookahead = true;
@@ -155,17 +238,41 @@ class input_stream_adapter
sb->sbumpc();
}
#if !JSON_DISABLE_STREAM_BULK_SCAN
// sgetc() refills the get area if it is exhausted
const bool refill = streambuf_access::get_ptr(sb) == streambuf_access::get_end(sb);
if (JSON_HEDLEY_UNLIKELY(refill))
{
save_token_segment();
}
#endif
auto res = sb->sgetc();
// set eof manually, as we don't use the istream interface.
if (JSON_HEDLEY_UNLIKELY(res == std::char_traits<char>::eof()))
{
// there is nothing to step over next time
lookahead = false;
#if !JSON_DISABLE_STREAM_BULK_SCAN
current_in_get_area = false;
#endif
is->clear(is->rdstate() | std::ios::eofbit);
}
else
{
lookahead = true;
#if !JSON_DISABLE_STREAM_BULK_SCAN
if (JSON_HEDLEY_UNLIKELY(refill))
{
// the peeked character is at gptr(), unless the streambuf has
// no get area
after_refill(res, streambuf_access::get_ptr(sb) != streambuf_access::get_end(sb));
}
else
{
current_in_get_area = true;
}
#endif
}
return res;
}
@@ -179,13 +286,6 @@ class input_stream_adapter
lookahead = false;
}
#else
input_stream_adapter(input_stream_adapter&& rhs) noexcept
: is(rhs.is), sb(rhs.sb)
{
rhs.is = nullptr;
rhs.sb = nullptr;
}
// std::istream/std::streambuf use std::char_traits<char>::to_int_type, to
// ensure that std::char_traits<char>::eof() and the character 0xFF do not
// end up as the same value, e.g., 0xFFFFFFFF.
@@ -194,12 +294,37 @@ class input_stream_adapter
// stays consumed after parsing; see JSON_PRECISE_STREAM_POSITION.
std::char_traits<char>::int_type get_character()
{
#if !JSON_DISABLE_STREAM_BULK_SCAN
// sbumpc() refills the get area if it is exhausted
const bool refill = streambuf_access::get_ptr(sb) == streambuf_access::get_end(sb);
if (JSON_HEDLEY_UNLIKELY(refill))
{
save_token_segment();
}
#endif
auto res = sb->sbumpc();
// set eof manually, as we don't use the istream interface.
if (JSON_HEDLEY_UNLIKELY(res == std::char_traits<char>::eof()))
{
#if !JSON_DISABLE_STREAM_BULK_SCAN
current_in_get_area = false;
#endif
is->clear(is->rdstate() | std::ios::eofbit);
}
#if !JSON_DISABLE_STREAM_BULK_SCAN
else if (JSON_HEDLEY_UNLIKELY(refill))
{
// the consumed character is at gptr() - 1, unless the streambuf
// has no get area and returned it from uflow()
const char* const next = streambuf_access::get_ptr(sb);
after_refill(res, next != nullptr && next != streambuf_access::get_begin(sb));
}
else
{
current_in_get_area = true;
}
#endif
return res;
}
#endif
@@ -218,7 +343,165 @@ class input_stream_adapter
return res;
}
#if !JSON_DISABLE_STREAM_BULK_SCAN
// The lexer may scan the characters in the get area of the streambuf
// directly (SWAR fast paths). The get area is only a window into the
// input: it ends wherever the streambuf's buffer ends, and is refilled by
// the next get_character(). The lexer therefore keeps counting the
// position itself and treats the end of the window as "unknown", not as
// the end of the input.
static constexpr bool supports_bulk_scan = true;
static constexpr bool bulk_window = true;
// Pointer to the next unread character; only valid when
// bulk_remaining() > 0. The character before it is the one last returned
// by get_character().
const char* bulk_data() const
{
return current_end();
}
// Number of unread characters in the get area.
std::size_t bulk_remaining() const
{
if (!current_in_get_area)
{
return 0;
}
return static_cast<std::size_t>(streambuf_access::get_end(sb) - current_end());
}
// Consume @a n characters previously inspected via bulk_data(); the last
// of them becomes the character last returned by get_character().
void bulk_skip(std::size_t n)
{
JSON_ASSERT(n <= bulk_remaining());
// gbump() takes an int, but a get area (e.g., of a std::stringbuf) can
// be larger
constexpr auto max_bump = static_cast<std::size_t>((std::numeric_limits<int>::max)());
for (; n > max_bump; n -= max_bump)
{
streambuf_access::bump(sb, static_cast<int>(max_bump));
}
streambuf_access::bump(sb, static_cast<int>(n));
}
// The adapter keeps the current token for the lexer's error messages: the
// part in the get area is only remembered as a pointer, and copied out
// when the get area is about to be refilled.
static constexpr bool supports_token_tracking = true;
// Start a token with the characters read from now on. Until this is
// called, nothing is tracked (the binary readers never call it).
void begin_token() noexcept
{
tracking_token = true;
token_carry.clear();
token_segment = current_end();
}
// Start a new token with the character @a c last returned by
// get_character().
void mark_token_start(std::char_traits<char>::int_type c)
{
tracking_token = true;
token_carry.clear();
if (current_in_get_area)
{
token_segment = current_end() - 1;
}
else
{
token_segment = nullptr;
token_carry.push_back(std::char_traits<char>::to_char_type(c));
}
}
// Copy the characters read since mark_token_start() to @a out, without the
// last one if @a drop_last.
void copy_token(std::vector<char>& out, bool drop_last) const
{
out = token_carry;
if (token_segment != nullptr)
{
out.insert(out.end(), token_segment, current_end());
}
if (drop_last && !out.empty())
{
out.pop_back();
}
}
#endif
private:
#if !JSON_DISABLE_STREAM_BULK_SCAN
// Reads the protected get-area pointers of any std::streambuf. Naming the
// members through a derived class makes forming the member pointers
// accessible; calling them on another streambuf object is then ordinary
// member access through a pointer to member.
struct streambuf_access : std::streambuf
{
static const char* get_ptr(std::streambuf* s)
{
return (s->*(&streambuf_access::gptr))();
}
static const char* get_end(std::streambuf* s)
{
return (s->*(&streambuf_access::egptr))();
}
static const char* get_begin(std::streambuf* s)
{
return (s->*(&streambuf_access::eback))();
}
static void bump(std::streambuf* s, int n)
{
(s->*(&streambuf_access::gbump))(n);
}
};
// one past the character last returned by get_character(), if that is in
// the get area
const char* current_end() const
{
#if JSON_PRECISE_STREAM_POSITION
// the character is peeked at gptr() and not stepped over yet, unless
// it was given back with release_lookahead()
return streambuf_access::get_ptr(sb) + (lookahead ? 1 : 0);
#else
return streambuf_access::get_ptr(sb);
#endif
}
// the get area is about to be replaced: copy the token's part in it
void save_token_segment()
{
if (token_segment != nullptr)
{
token_carry.insert(token_carry.end(), token_segment, streambuf_access::get_end(sb));
token_segment = nullptr;
}
}
// character @a c was just read into a new get area (@a in_get_area) or
// returned without one
void after_refill(std::char_traits<char>::int_type c, bool in_get_area)
{
current_in_get_area = in_get_area;
if (!tracking_token)
{
return;
}
if (in_get_area)
{
token_segment = current_end() - 1;
}
else
{
token_carry.push_back(std::char_traits<char>::to_char_type(c));
}
}
#endif
#if JSON_PRECISE_STREAM_POSITION
// Step over the character last returned by get_character(). The character
// has already been peeked successfully, so for every streambuf with a get
@@ -240,6 +523,16 @@ class input_stream_adapter
/// whether get_character() peeked a character that is not consumed yet
bool lookahead = false;
#endif
#if !JSON_DISABLE_STREAM_BULK_SCAN
/// the part of the current token that was in earlier get areas
std::vector<char> token_carry{}; // NOLINT(readability-redundant-member-init)
/// start of the current token's part in the get area, or nullptr
const char* token_segment = nullptr;
/// whether the character last returned by get_character() is in the get area
bool current_in_get_area = false;
/// whether a token is tracked at all; the binary readers never start one
bool tracking_token = false;
#endif
};
#endif // JSON_NO_IO
include/nlohmann/detail/input/json_sax.hpp
+14 -4
View File
@@ -187,12 +187,19 @@ Shared by json_sax_dom_parser and json_sax_dom_callback_parser.
@param[in] ref the object or array that was just created
@return whether parsing should continue (false after reporting out_of_range.408)
*/
template<typename SAX, typename BasicJsonType>
JSON_HEDLEY_NEVER_INLINE
bool container_too_large_error(SAX& sax, std::size_t len, const char* kind, BasicJsonType* ref)
{
return sax.parse_error(0, "", out_of_range::create(exception_id::container_too_large, concat("excessive ", kind, " size: ", std::to_string(len)), ref));
}
template<typename SAX, typename BasicJsonType>
bool check_container_size(SAX& sax, std::size_t len, const char* kind, BasicJsonType* ref)
{
if (JSON_HEDLEY_UNLIKELY(len != detail::unknown_size() && len > ref->max_size()))
{
return sax.parse_error(0, "", out_of_range::create(exception_id::container_too_large, concat("excessive ", kind, " size: ", std::to_string(len)), ref));
return container_too_large_error(sax, len, kind, ref);
}
return true;
}
@@ -674,16 +681,19 @@ class json_sax_dom_callback_parser
if (keep && ref_stack.back())
{
auto& obj = *ref_stack.back()->m_data.m_value.object;
const auto it = obj.find(val);
if (it != obj.end())
// a single lookup: insert the placeholder, or find the existing member
const auto inserted = obj.emplace(val, discarded);
const auto it = inserted.first;
if (!inserted.second)
{
// this is a duplicate key (legal in JSON); remember its
// current value so it can be restored later if the new
// value is rejected by the callback, instead of being
// erased together with the discarded placeholder
duplicate_key_stash.emplace_back(&(it->second), it->second);
it->second = discarded;
}
object_element = &(obj[val] = discarded);
object_element = &(it->second);
}
return true;
include/nlohmann/detail/input/lexer.hpp
+349 -72
View File
@@ -12,6 +12,7 @@
#include <cstddef> // size_t
#include <cstdint> // uint32_t
#include <cstdio> // snprintf
#include <cstring> // memcmp
#include <initializer_list> // initializer_list
#include <string> // char_traits, string
#include <utility> // move
@@ -166,6 +167,43 @@ constexpr bool input_adapter_supports_bulk_scan(std::false_type /*detected*/)
return false;
}
// Detect whether an input adapter keeps the current token itself and can
// hand it out on demand (see input_stream_adapter::supports_token_tracking),
// so the lexer need not copy every scanned character into token_string.
template<typename InputAdapterType>
using detect_supports_token_tracking = decltype(InputAdapterType::supports_token_tracking);
template<typename InputAdapterType>
constexpr bool input_adapter_supports_token_tracking(std::true_type /*detected*/)
{
return InputAdapterType::supports_token_tracking;
}
template<typename InputAdapterType>
constexpr bool input_adapter_supports_token_tracking(std::false_type /*detected*/)
{
return false;
}
// Detect whether the contiguous block of a bulk-scan adapter is only a window
// into the input (see input_stream_adapter::bulk_window): its end is not the
// end of the input, so a token that touches it must be finished character by
// character.
template<typename InputAdapterType>
using detect_bulk_window = decltype(InputAdapterType::bulk_window);
template<typename InputAdapterType>
constexpr bool input_adapter_bulk_window(std::true_type /*detected*/)
{
return InputAdapterType::bulk_window;
}
template<typename InputAdapterType>
constexpr bool input_adapter_bulk_window(std::false_type /*detected*/)
{
return false;
}
/*!
@brief lexical analysis
@@ -184,9 +222,20 @@ class lexer : public lexer_base<BasicJsonType>
/// whether the last read token can be reconstructed from the input adapter
/// on demand (in error paths) instead of being copied on every scanned
/// character; see input_adapter_supports_seek
static constexpr bool lazy_token_string =
static constexpr bool seekable =
input_adapter_supports_seek<InputAdapterType>(is_detected<detect_supports_seek, InputAdapterType> {});
/// whether the adapter keeps the token itself (mark_token_start() /
/// copy_token()); see input_adapter_supports_token_tracking
static constexpr bool adapter_token =
!seekable && input_adapter_supports_token_tracking<InputAdapterType>(is_detected<detect_supports_token_tracking, InputAdapterType> {});
/// whether the last read token is obtained from the input adapter on
/// demand (in error paths) instead of being copied on every scanned
/// character: seekable adapters reconstruct it from the consumed input,
/// token-tracking adapters keep it themselves
static constexpr bool lazy_token_string = seekable || adapter_token;
/// whether the read position is derived from the input adapter on demand
/// instead of being counted on every scanned character. Seekable adapters
/// know how much input they consumed and can revisit it, so
@@ -194,7 +243,7 @@ class lexer : public lexer_base<BasicJsonType>
/// and line and column are recomputed from the consumed input only when
/// get_position() is called (errors). Counting per character kept two
/// increments and a newline check in the hot path of every get().
static constexpr bool lazy_position = lazy_token_string;
static constexpr bool lazy_position = seekable;
/// whether a simulated unget can be passed on to the input adapter, which
/// then leaves the character in the input; see
@@ -203,14 +252,17 @@ class lexer : public lexer_base<BasicJsonType>
input_adapter_supports_lookahead<InputAdapterType>(is_detected<detect_supports_lookahead, InputAdapterType> {});
/// whether string scanning may bulk-consume runs of ordinary characters
/// directly from a contiguous input buffer (SWAR fast path). This requires
/// the token to be reconstructible lazily (lazy_token_string), so bypassing
/// the per-character capture in get() cannot lose error diagnostics. It
/// also implies lazy_position, so the bulk paths need not advance the
/// position counters.
/// directly from a contiguous input buffer (SWAR fast path). Without
/// lazy_token_string / lazy_position, the bulk paths copy the consumed
/// characters into token_string and advance the position counters
/// themselves (see bulk_consume).
static constexpr bool bulk_scan =
lazy_token_string
&& input_adapter_supports_bulk_scan<InputAdapterType>(is_detected<detect_supports_bulk_scan, InputAdapterType> {});
input_adapter_supports_bulk_scan<InputAdapterType>(is_detected<detect_supports_bulk_scan, InputAdapterType> {});
/// whether the contiguous block is only a window into the input, so that
/// its end does not end a token; see input_adapter_bulk_window
static constexpr bool bulk_window =
input_adapter_bulk_window<InputAdapterType>(is_detected<detect_bulk_window, InputAdapterType> {});
public:
using token_type = typename lexer_base<BasicJsonType>::token_type;
@@ -219,7 +271,11 @@ class lexer : public lexer_base<BasicJsonType>
: ia(std::move(adapter))
, ignore_comments(ignore_comments_)
, discard_number_values(discard_number_values_)
{}
{
// the token string of an error before the first token is everything
// read so far
begin_token(std::integral_constant<bool, adapter_token> {});
}
// deleted because of pointer members
lexer(const lexer&) = delete;
@@ -236,8 +292,8 @@ class lexer : public lexer_base<BasicJsonType>
/// contiguous input: try to decode the 4 hex digits following `\\u`
/// directly from the input buffer via hex_codepoint(), instead of 4 calls
/// to get(). On success, advances the adapter exactly as those 4 get()
/// calls would (bulk_scan implies lazy_position, so there are no position
/// counters to advance) and leaves @a current holding the last of
/// calls would (including the position and token bookkeeping of a
/// streaming adapter, see bulk_consume) and leaves @a current holding the last of
/// the 4 digits, just as the last such get() would; the codepoint is
/// written to @a out. Makes no state change and returns false for a
/// pending unget, fewer than 4 remaining bytes, or any of the 4 bytes not
@@ -256,7 +312,7 @@ class lexer : public lexer_base<BasicJsonType>
{
return false;
}
ia.bulk_skip(4);
bulk_consume(reinterpret_cast<const char*>(raw), 4);
current = char_traits<char_type>::to_int_type(raw[3]);
out = codepoint;
return true;
@@ -362,34 +418,79 @@ class lexer : public lexer_base<BasicJsonType>
}
/// contiguous input: bulk-append the run of ordinary characters and complete
/// well-formed UTF-8 sequences starting at the current read position, leaving
/// the first byte that needs individual handling (the closing quote, an
/// escape, a control character, or an ill-formed UTF-8 byte) for get()
void scan_string_bulk(std::true_type /*bulk*/)
/// well-formed UTF-8 sequences starting at the current read position, then
/// read the first byte that needs individual handling (the closing quote, an
/// escape, a control character, or an ill-formed UTF-8 byte) like get().
/// That byte is taken from the buffer that was just scanned. Through get(),
/// Apple Clang merged this read with the other get() calls of the scan
/// function, which load the read position again right after it was stored
/// (3% of json::accept() on jeopardy.json on Apple M1).
char_int_type get_after_string_run(std::true_type /*bulk*/)
{
// a pending unget must be consumed through the normal path first
if (next_unget)
{
return;
return get();
}
const std::size_t remaining = ia.bulk_remaining();
if (remaining == 0)
{
return;
return get();
}
const auto* const data = reinterpret_cast<const unsigned char*>(ia.bulk_data());
const auto* const raw = ia.bulk_data();
const auto* const data = reinterpret_cast<const unsigned char*>(raw);
const std::size_t pos = string_bulk_run(data, remaining);
if (pos == 0)
const std::size_t pos = lexer_string_bulk_run(data, remaining);
if (pos != 0)
{
return;
token_buffer.append(reinterpret_cast<const typename string_t::value_type*>(data), pos);
bulk_consume(reinterpret_cast<const char*>(data), pos);
}
token_buffer.append(reinterpret_cast<const typename string_t::value_type*>(data), pos);
ia.bulk_skip(pos);
if (pos == remaining)
{
return get(); // end of the contiguous input
}
// what get() does, with the byte at hand
advance_position();
ia.bulk_skip(1);
current = char_traits<char_type>::to_int_type(raw[pos]);
return track_after_read();
}
/// consume @a n characters at @a data (the adapter's bulk_data()) and do
/// the bookkeeping get() would have done for them; the characters are
/// never newlines
void bulk_consume(const char* data, std::size_t n)
{
bulk_track_position(n, std::integral_constant<bool, lazy_position> {});
bulk_track_token(data, n, std::integral_constant<bool, lazy_token_string> {});
ia.bulk_skip(n);
}
/// seekable adapter: the position is derived from the adapter
void bulk_track_position(std::size_t /*n*/, std::true_type /*lazy*/) const noexcept {}
/// streaming adapter: count the characters
void bulk_track_position(std::size_t n, std::false_type /*lazy*/) noexcept
{
position.chars_read_total += n;
position.chars_read_current_line += n;
}
/// the token is obtained from the adapter
void bulk_track_token(const char* /*data*/, std::size_t /*n*/, std::true_type /*lazy*/) const noexcept {}
/// streaming adapter: capture the characters
void bulk_track_token(const char* data, std::size_t n, std::false_type /*lazy*/)
{
token_string.insert(token_string.end(), data, data + n);
}
/// streaming input: no bulk fast path
void scan_string_bulk(std::false_type /*bulk*/) const noexcept {}
char_int_type get_after_string_run(std::false_type /*bulk*/)
{
return get();
}
/*!
@brief scan a string literal
@@ -417,11 +518,8 @@ class lexer : public lexer_base<BasicJsonType>
while (true)
{
// bulk-consume ordinary characters from contiguous input, then
// handle the next special byte through the switch below
scan_string_bulk(std::integral_constant<bool, bulk_scan> {});
// get the next character
switch (get())
// get the next character, the one that ends the run
switch (get_after_string_run(std::integral_constant<bool, bulk_scan>()))
{
// end of file while parsing the string
case char_traits<char_type>::eof():
@@ -1541,9 +1639,12 @@ scan_number_done:
const std::size_t avail = rem + 1;
// validate + classify the number extent (mirrors scan_number()'s grammar)
// and accumulate the mantissa digits on the way, so that tokens with up
// to 19 digits need no second pass for their value
std::size_t i = 0;
std::size_t dot_index = std::string::npos;
token_type number_type = token_type::value_unsigned;
std::uint64_t w = 0;
if (data[0] == '-')
{
number_type = token_type::value_integer;
@@ -1553,22 +1654,21 @@ scan_number_done:
return token_type::uninitialized;
}
}
const std::size_t integer_begin = i;
if (data[i] == '0')
{
++i;
}
else if (data[i] >= '1' && data[i] <= '9')
{
++i;
while (i < avail && data[i] >= '0' && data[i] <= '9')
{
++i;
}
i = accumulate_digits(data, i, avail, w);
}
else
{
return token_type::uninitialized;
}
std::size_t digit_count = i - integer_begin;
std::size_t fraction_digits = 0;
if (i < avail && data[i] == '.')
{
number_type = token_type::value_float;
@@ -1578,31 +1678,45 @@ scan_number_done:
{
return token_type::uninitialized;
}
while (i < avail && data[i] >= '0' && data[i] <= '9')
{
++i;
}
const std::size_t fraction_begin = i;
i = accumulate_digits(data, i, avail, w);
fraction_digits = i - fraction_begin;
digit_count += fraction_digits;
}
// the mantissa ends here, whether or not an exponent part follows
const std::size_t mantissa_end = i;
std::int64_t exponent = 0;
if (i < avail && (data[i] == 'e' || data[i] == 'E'))
{
number_type = token_type::value_float;
++i;
bool negative_exponent = false;
if (i < avail && (data[i] == '+' || data[i] == '-'))
{
negative_exponent = data[i] == '-';
++i;
}
if (i >= avail || !(data[i] >= '0' && data[i] <= '9'))
{
return token_type::uninitialized;
}
// saturated far beyond every range, see parse_float_exponent()
constexpr std::int64_t saturation = 100000000000000000; // 10^17
while (i < avail && data[i] >= '0' && data[i] <= '9')
{
if (exponent < saturation)
{
exponent = (exponent * 10) + (data[i] - '0');
}
++i;
}
exponent = negative_exponent ? -exponent : exponent;
}
const std::size_t len = i;
if (number_may_continue(len == avail, std::integral_constant<bool, bulk_window> {}))
{
return token_type::uninitialized;
}
// reset() records where this token starts (for diagnostics), so it has
// to run before the input position advances below
@@ -1617,10 +1731,14 @@ scan_number_done:
#if !JSON_DIAGNOSTIC_POSITIONS
if (number_type != token_type::value_float)
{
const token_type integer_result = convert_integer(number_type, data, data + len);
// up to 18 digits always fit into std::uint64_t and std::int64_t
const token_type integer_result = (digit_count <= 18)
? store_integer(number_type, w)
: convert_integer(number_type, data, data + len);
if (JSON_HEDLEY_LIKELY(integer_result != token_type::uninitialized))
{
ia.bulk_skip(len - 1);
bulk_consume(data + 1, len - 1);
read_number_terminator(std::integral_constant<bool, bulk_window> {});
return integer_result;
}
// The value does not fit an integer, so this token converts as a
@@ -1630,17 +1748,99 @@ scan_number_done:
}
#endif
decimal_point_position = dot_index;
bulk_consume(data + 1, len - 1);
read_number_terminator(std::integral_constant<bool, bulk_window> {});
// a float whose digits all fit into w converts from the accumulated
// value; longer ones (and other float formats) take the general path
if (number_type == token_type::value_float && digit_count <= 19)
{
float_significand s;
s.w = w;
s.exponent = exponent - static_cast<std::int64_t>(fraction_digits);
s.negative = data[0] == '-';
if (convert_accumulated_float(s, std::integral_constant<bool, has_native_float_format<number_float_t>::value> {}))
{
// the token text is only copied into token_buffer when
// get_string() asks for it; the library's own SAX handlers
// ignore it. A window into a stream may be refilled by the
// next read, so there the text is copied right away.
if (bulk_window)
{
token_buffer.append(reinterpret_cast<const typename string_t::value_type*>(data), len);
}
else
{
pending_number_text = data;
pending_number_length = len;
}
return token_type::value_float;
}
}
// materialize the token exactly as scan_number() would. reset() already
// cleared token_buffer, so append() fills it (assign() is avoided
// because custom string_t types need not provide it)
token_buffer.append(reinterpret_cast<const typename string_t::value_type*>(data), len);
decimal_point_position = dot_index;
ia.bulk_skip(len - 1);
return convert_number(number_type, mantissa_end);
}
/// window adapter: a number that reaches the end of the window may continue
/// after it, so scan_number() has to read it character by character
static constexpr bool number_may_continue(bool at_end, std::true_type /*window*/) noexcept
{
return at_end;
}
/// the end of the block is the end of the input, which ends the number
static constexpr bool number_may_continue(bool /*at_end*/, std::false_type /*window*/) noexcept
{
return false;
}
/// window adapter: read the character after a bulk-scanned number and unget
/// it, as scan_number() does. The adapter is a stream that is handed back to
/// the user, who must find the same input consumed either way.
void read_number_terminator(std::true_type /*window*/)
{
get();
unget();
}
/// the input is not handed back, so the terminator can stay unread
void read_number_terminator(std::false_type /*window*/) const noexcept {}
/// binary32/binary64: the value of a float token from its accumulated
/// significand (see scan_number_bulk_contiguous())
bool convert_accumulated_float(const float_significand& s, std::true_type /*native*/) noexcept
{
value_float = decimal_to_float<number_float_t>(s);
return true;
}
/// other formats (e.g. x87 long double): not instantiated for them, as
/// decimal_to_float() only supports binary32/binary64
static bool convert_accumulated_float(const float_significand& /*s*/, std::false_type /*native*/) noexcept
{
return false;
}
/// the value of an integer token with at most 18 digits, accumulated in @a w
token_type store_integer(token_type number_type, std::uint64_t w) noexcept
{
if (number_type == token_type::value_unsigned)
{
value_unsigned = static_cast<number_unsigned_t>(w);
// reject values that do not round-trip into a narrower type
return (static_cast<std::uint64_t>(value_unsigned) == w) ? token_type::value_unsigned : token_type::uninitialized;
}
const std::int64_t x = -static_cast<std::int64_t>(w);
value_integer = static_cast<number_integer_t>(x);
return (static_cast<std::int64_t>(value_integer) == x) ? token_type::value_integer : token_type::uninitialized;
}
/// contiguous input: try the number fast path, else the byte-path scanner
token_type scan_number_dispatch(std::true_type /*bulk*/)
{
@@ -1655,18 +1855,23 @@ scan_number_done:
}
/*!
@param[in] literal_text the literal text to expect
@param[in] length the length of the passed literal text
@param[in] return_type the token type to return on success
@param[in] rest the literal text after its first character, which
is current (its length is a template parameter, so
that the comparison of the contiguous fast path is
a fixed-size load, not a call of memcmp)
@param[in] return_type the token type to return on success
*/
JSON_HEDLEY_NON_NULL(2)
token_type scan_literal(const char_type* literal_text, const std::size_t length,
token_type return_type)
template<std::size_t N>
JSON_HEDLEY_NEVER_INLINE token_type scan_literal(const char (&rest)[N], token_type return_type) // NOLINT(cppcoreguidelines-avoid-c-arrays,hicpp-avoid-c-arrays,modernize-avoid-c-arrays)
{
JSON_ASSERT(char_traits<char_type>::to_char_type(current) == literal_text[0]);
for (std::size_t i = 1; i < length; ++i)
constexpr std::size_t length = N - 1;
if (scan_literal_bulk(rest, length, std::integral_constant<bool, bulk_scan> {}))
{
if (JSON_HEDLEY_UNLIKELY(char_traits<char_type>::to_char_type(get()) != literal_text[i]))
return return_type;
}
for (std::size_t i = 0; i < length; ++i)
{
if (JSON_HEDLEY_UNLIKELY(char_traits<char_type>::to_char_type(get()) != static_cast<char_type>(rest[i])))
{
error_message = "invalid literal";
return token_type::parse_error;
@@ -1675,6 +1880,27 @@ scan_number_done:
return return_type;
}
/// contiguous input: compare the rest of a literal at once; false (and
/// nothing consumed) if it does not match, so that the byte path reports
/// the error at the right character
JSON_HEDLEY_ALWAYS_INLINE bool scan_literal_bulk(const char* rest, const std::size_t length, std::true_type /*bulk*/)
{
if (next_unget || ia.bulk_remaining() < length
|| std::memcmp(ia.bulk_data(), rest, length) != 0)
{
return false;
}
bulk_consume(reinterpret_cast<const char*>(ia.bulk_data()), length);
current = static_cast<char_int_type>(static_cast<unsigned char>(rest[length - 1]));
return true;
}
/// streaming input: no bulk fast path
bool scan_literal_bulk(const char* /*rest*/, const std::size_t /*length*/, std::false_type /*bulk*/) const noexcept
{
return false;
}
/////////////////////
// input management
/////////////////////
@@ -1683,6 +1909,7 @@ scan_number_done:
void reset() noexcept
{
token_buffer.clear();
pending_number_text = nullptr;
decimal_point_position = std::string::npos;
#if JSON_DIAGNOSTIC_POSITIONS
@@ -1696,11 +1923,30 @@ scan_number_done:
/// seekable adapter: remember where the current token starts so it can be
/// reconstructed from the input on error; current has already been
/// consumed, hence the -1
void note_token_start(std::true_type /*lazy*/) noexcept
void note_token_start(std::true_type /*lazy*/)
{
note_token_start_lazy(std::integral_constant<bool, adapter_token> {});
}
void note_token_start_lazy(std::false_type /*adapter_token*/) noexcept
{
token_string_start = ia.get_consumed_count() - 1;
}
/// token-tracking adapter: start tracking the token at the first character
void begin_token(std::true_type /*adapter_token*/) noexcept
{
ia.begin_token();
}
void begin_token(std::false_type /*adapter_token*/) const noexcept {}
/// token-tracking adapter: the token starts with the current character
void note_token_start_lazy(std::true_type /*adapter_token*/)
{
ia.mark_token_start(current);
}
/// streaming adapter: start copying the token eagerly, beginning with the
/// already-read first character
void note_token_start(std::false_type /*lazy*/) noexcept
@@ -1923,10 +2169,30 @@ scan_number_done:
/// return current string value
string_t& get_string()
{
if (pending_number_text != nullptr)
{
token_buffer.append(reinterpret_cast<const typename string_t::value_type*>(pending_number_text), pending_number_length);
pending_number_text = nullptr;
}
// a number token holds '.' regardless of the locale (#4084)
return token_buffer;
}
/// the value of a string token (key or string), which never has pending
/// number text, so get_string()'s check is not needed
string_t& get_string_token() noexcept
{
JSON_ASSERT(pending_number_text == nullptr);
return token_buffer;
}
/// the text of a float token for a SAX handler that ignores it (the
/// library's own handlers): empty, without copying the token
const string_t& get_ignored_number_text() const noexcept
{
return token_buffer;
}
/////////////////////
// diagnostics
/////////////////////
@@ -2021,6 +2287,20 @@ scan_number_done:
public:
/// seekable adapter: rebuild the last read token from the input on demand
const std::vector<char_type>& collect_token_chars(std::vector<char_type>& out, std::true_type /*lazy*/) const
{
return collect_token_chars_lazy(out, std::integral_constant<bool, adapter_token> {});
}
/// token-tracking adapter: the adapter hands out everything read since
/// mark_token_start(), except a pending unget (see below)
const std::vector<char_type>& collect_token_chars_lazy(std::vector<char_type>& out, std::true_type /*adapter_token*/) const
{
const bool pending_real_unget = next_unget && current != char_traits<char_type>::eof();
ia.copy_token(out, pending_real_unget);
return out;
}
const std::vector<char_type>& collect_token_chars_lazy(std::vector<char_type>& out, std::false_type /*adapter_token*/) const
{
// a pending unget of a real (non-EOF) character means that character
// was consumed from the input but is not part of the token; EOF is
@@ -2142,9 +2422,8 @@ scan_number_done:
Pretty-printed JSON indents every line with a run of spaces, which the loop
in skip_whitespace() would otherwise read one character at a time. The
spaces are skipped 8 bytes at a time; the last 7 bytes of the input and any
other whitespace are left to that loop. Skipping bypasses get(), which is
fine because bulk_scan implies lazy_position: the position is derived from
the adapter, not counted per character.
other whitespace are left to that loop. Skipping bypasses get();
bulk_consume() does its bookkeeping.
*/
void skip_indentation(std::true_type /*bulk*/)
{
@@ -2167,7 +2446,7 @@ scan_number_done:
break;
}
}
ia.bulk_skip(pos);
bulk_consume(data, pos);
}
/// streaming input: no bulk fast path
@@ -2247,21 +2526,14 @@ scan_number_done:
return token_type::value_separator;
// literals
// (the text after the first character; no local arrays, which
// would give this function a stack canary on every token)
case 't':
{
std::array<char_type, 4> true_literal = {{static_cast<char_type>('t'), static_cast<char_type>('r'), static_cast<char_type>('u'), static_cast<char_type>('e')}};
return scan_literal(true_literal.data(), true_literal.size(), token_type::literal_true);
}
return scan_literal("rue", token_type::literal_true);
case 'f':
{
std::array<char_type, 5> false_literal = {{static_cast<char_type>('f'), static_cast<char_type>('a'), static_cast<char_type>('l'), static_cast<char_type>('s'), static_cast<char_type>('e')}};
return scan_literal(false_literal.data(), false_literal.size(), token_type::literal_false);
}
return scan_literal("alse", token_type::literal_false);
case 'n':
{
std::array<char_type, 4> null_literal = {{static_cast<char_type>('n'), static_cast<char_type>('u'), static_cast<char_type>('l'), static_cast<char_type>('l')}};
return scan_literal(null_literal.data(), null_literal.size(), token_type::literal_null);
}
return scan_literal("ull", token_type::literal_null);
// string
case '\"':
@@ -2309,6 +2581,11 @@ scan_number_done:
/// whether the next get() call should just return current
bool next_unget = false;
/// the text of the current float token in the input, not yet copied into
/// token_buffer (see get_string()), or nullptr
const char* pending_number_text = nullptr;
std::size_t pending_number_length = 0;
/// the start position of the current token
position_t position {};
include/nlohmann/detail/input/number_parse.hpp
+92 -30
View File
@@ -19,7 +19,7 @@
#include <cstring> // memcpy
#include <limits> // numeric_limits
#include <string> // string
#include <type_traits> // conditional, integral_constant, true_type, false_type
#include <type_traits> // conditional, integral_constant, is_signed, true_type, false_type
#include <utility> // move
#include <nlohmann/detail/bit_ops.hpp>
@@ -50,6 +50,20 @@ NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
{
// whether an integer of a signed type is negative; the overload for other types
// avoids comparing an unsigned value with zero
template<typename NumberType>
constexpr bool is_negative_integer(NumberType x, std::true_type /*is_signed*/) noexcept
{
return x < 0;
}
template<typename NumberType>
constexpr bool is_negative_integer(NumberType /*unused*/, std::false_type /*is_signed*/) noexcept
{
return false;
}
/*!
@brief fast integer parser for an already-validated unsigned integer
@@ -83,8 +97,10 @@ bool parse_integer_unsigned(const char* first, const char* last, NumberUnsignedT
x = (x * 10u) + digit;
}
value = static_cast<NumberUnsignedType>(x);
// reject values that do not round-trip into a narrower NumberUnsignedType
return static_cast<std::uint64_t>(value) == x;
// reject values that do not round-trip into a narrower NumberUnsignedType,
// and values that wrap around to negative numbers if it is a signed type
// (number_unsigned_t may be the same type as number_integer_t, #2573)
return static_cast<std::uint64_t>(value) == x && !is_negative_integer(value, std::is_signed<NumberUnsignedType>());
}
/*!
@@ -259,13 +275,77 @@ JSON_HEDLEY_ALWAYS_INLINE std::uint32_t parse_eight_digits(std::uint64_t v) noex
return static_cast<std::uint32_t>(((v & 0x0000FFFF0000FFFFu) * 42949672960001u) >> 32u);
}
/// whether [first, last) contains a digit other than '0'
inline bool has_nonzero_digit(const char* first, const char* last) noexcept
/// whether the eight bytes in @a v (see read_eight_bytes()) are all ASCII
/// digits (after fast_float)
JSON_HEDLEY_ALWAYS_INLINE bool is_eight_digits(std::uint64_t v) noexcept
{
return std::any_of(first, last, [](char c) noexcept
return ((v & 0xF0F0F0F0F0F0F0F0u) | (((v + 0x0606060606060606u) & 0xF0F0F0F0F0F0F0F0u) >> 4u)) == 0x3333333333333333u;
}
/*!
@brief skip the ASCII digits starting at data[i] and accumulate their value
Eight digits are taken at a time while at least eight bytes remain. @a w wraps
around after 19 digits; the caller only uses it for shorter digit runs.
@return the index of the first byte at or after @a i that is not a digit
*/
JSON_HEDLEY_ALWAYS_INLINE std::size_t accumulate_digits(const char* data, std::size_t i, std::size_t avail, std::uint64_t& w) noexcept
{
while (avail - i >= 8)
{
return c != '0';
});
const std::uint64_t v = read_eight_bytes(data + i);
if (!is_eight_digits(v))
{
break;
}
w = (w * 100000000u) + parse_eight_digits(v);
i += 8;
}
while (i < avail && data[i] >= '0' && data[i] <= '9')
{
w = (w * 10u) + static_cast<std::uint64_t>(data[i] - '0');
++i;
}
return i;
}
/// whether [first, last) contains a digit other than '0'; a plain loop, as
/// GCC calls std::any_of out of line even for the usual empty range
JSON_HEDLEY_ALWAYS_INLINE bool has_nonzero_digit(const char* first, const char* last) noexcept
{
for (; first != last; ++first)
{
if (*first != '0')
{
return true;
}
}
return false;
}
/*!
@brief accumulate the validated digits [p, last) into @a w, as long as
@a remaining digits still fit into it
Eight digits are taken at a time while at least eight remain, and @a remaining
is decreased by the number of digits taken.
@return a pointer past the last digit taken
*/
JSON_HEDLEY_ALWAYS_INLINE const char* accumulate_significant_digits(const char* p, const char* last, int& remaining, std::uint64_t& w) noexcept
{
while (remaining >= 8 && last - p >= 8)
{
w = (w * 100000000u) + parse_eight_digits(read_eight_bytes(p));
p += 8;
remaining -= 8;
}
for (; remaining > 0 && p != last; ++p, --remaining)
{
w = (w * 10u) + static_cast<std::uint64_t>(*p - '0');
}
return p;
}
/// the value of the validated exponent digits [+-]?[0-9]+ in [first, last),
@@ -311,7 +391,7 @@ truncated is set.
std::string::npos if there is none
@param[in] mantissa_end index of the 'e'/'E', or the token length
*/
inline float_significand parse_float_significand(const char* first, const char* last,
JSON_HEDLEY_ALWAYS_INLINE float_significand parse_float_significand(const char* first, const char* last,
std::size_t decimal_point_position, std::size_t mantissa_end) noexcept
{
float_significand s;
@@ -326,16 +406,7 @@ inline float_significand parse_float_significand(const char* first, const char*
int remaining = 19; // digits that still fit into w
if (*p != '0') // the integer part is "0" or [1-9][0-9]*
{
while (remaining >= 8 && integer_last - p >= 8)
{
w = (w * 100000000u) + parse_eight_digits(read_eight_bytes(p));
p += 8;
remaining -= 8;
}
for (; remaining > 0 && p != integer_last; ++p, --remaining)
{
w = (w * 10u) + static_cast<std::uint64_t>(*p - '0');
}
p = accumulate_significant_digits(p, integer_last, remaining, w);
s.exponent = integer_last - p;
s.truncated = has_nonzero_digit(p, integer_last);
}
@@ -354,16 +425,7 @@ inline float_significand parse_float_significand(const char* first, const char*
s.exponent -= p - zeros;
}
const char* const digits = p;
while (remaining >= 8 && mantissa_last - p >= 8)
{
w = (w * 100000000u) + parse_eight_digits(read_eight_bytes(p));
p += 8;
remaining -= 8;
}
for (; remaining > 0 && p != mantissa_last; ++p, --remaining)
{
w = (w * 10u) + static_cast<std::uint64_t>(*p - '0');
}
p = accumulate_significant_digits(p, mantissa_last, remaining, w);
s.exponent -= p - digits;
s.truncated = s.truncated || has_nonzero_digit(p, mantissa_last);
}
@@ -704,7 +766,7 @@ inline void float_from_bits(std::uint64_t bits, float& value) noexcept
{
static_assert(sizeof(float) == sizeof(std::uint32_t), "float must have 32 bits");
const auto bits32 = static_cast<std::uint32_t>(bits);
std::memcpy(&value, &bits32, sizeof(value));
std::memcpy(&value, &bits32, sizeof(bits32));
}
/// the powers of ten that are exact in binary64 (up to 10^22)
include/nlohmann/detail/input/parser.hpp
+41 -9
View File
@@ -51,6 +51,20 @@ template<typename BasicJsonType>
using parser_callback_t =
std::function<bool(int /*depth*/, parse_event_t /*event*/, BasicJsonType& /*parsed*/)>;
/// whether a SAX handler ignores the text of float tokens (the library's own
/// handlers do), so that the parser need not materialize it
template<typename SAX>
struct sax_ignores_number_text : std::false_type {};
template<typename BasicJsonType, typename InputAdapterType>
struct sax_ignores_number_text<json_sax_dom_parser<BasicJsonType, InputAdapterType>> : std::true_type {};
template<typename BasicJsonType, typename InputAdapterType>
struct sax_ignores_number_text<json_sax_dom_callback_parser<BasicJsonType, InputAdapterType>> : std::true_type {};
template<typename BasicJsonType>
struct sax_ignores_number_text<json_sax_acceptor<BasicJsonType>> : std::true_type {};
/*!
@brief syntax analysis
@@ -171,6 +185,23 @@ class parser
}
private:
/// the text of the current float token for @a sax (see sax_ignores_number_text)
template<typename SAX>
const string_t& number_float_text(SAX* /*sax*/)
{
return number_float_text(std::integral_constant<bool, sax_ignores_number_text<SAX>::value> {});
}
const string_t& number_float_text(std::true_type /*ignored*/) const noexcept
{
return m_lexer.get_ignored_number_text();
}
string_t& number_float_text(std::false_type /*ignored*/)
{
return m_lexer.get_string();
}
/*!
@brief run a DOM SAX parser to completion and position the lexer
@@ -213,8 +244,9 @@ class parser
bool sax_parse_internal(SAX* sax)
{
// stack to remember the hierarchy of structured values we are parsing
// true = array; false = object
std::vector<bool> states;
// true = array; false = object (bytes, not std::vector<bool>, whose
// push_back() is a call with GCC)
std::vector<std::uint8_t> states;
// value to avoid a goto (see comment where set to true)
bool skip_to_state_evaluation = false;
@@ -247,7 +279,7 @@ class parser
{
return syntax_error(*sax, exception_message(token_type::value_string, "object key"));
}
if (JSON_HEDLEY_UNLIKELY(!sax->key(m_lexer.get_string())))
if (JSON_HEDLEY_UNLIKELY(!sax->key(m_lexer.get_string_token())))
{
return false;
}
@@ -259,7 +291,7 @@ class parser
}
// remember we are now inside an object
states.push_back(false);
states.push_back(0);
// parse values
get_token();
@@ -284,7 +316,7 @@ class parser
}
// remember we are now inside an array
states.push_back(true);
states.push_back(1);
// parse values (no need to call get_token)
continue;
@@ -301,7 +333,7 @@ class parser
out_of_range::create(exception_id::number_overflow, concat("number overflow parsing '", m_lexer.get_token_string(), '\''), nullptr));
}
if (JSON_HEDLEY_UNLIKELY(!sax->number_float(res, m_lexer.get_string())))
if (JSON_HEDLEY_UNLIKELY(!sax->number_float(res, number_float_text(sax))))
{
return false;
}
@@ -347,7 +379,7 @@ class parser
case token_type::value_string:
{
if (JSON_HEDLEY_UNLIKELY(!sax->string(m_lexer.get_string())))
if (JSON_HEDLEY_UNLIKELY(!sax->string(m_lexer.get_string_token())))
{
return false;
}
@@ -401,7 +433,7 @@ class parser
return true;
}
if (states.back()) // array
if (states.back() != 0) // array
{
// comma -> next value
// or end of array (ignore_trailing_commas = true)
@@ -456,7 +488,7 @@ class parser
return syntax_error(*sax, exception_message(token_type::value_string, "object key"));
}
if (JSON_HEDLEY_UNLIKELY(!sax->key(m_lexer.get_string())))
if (JSON_HEDLEY_UNLIKELY(!sax->key(m_lexer.get_string_token())))
{
return false;
}
include/nlohmann/detail/input/simd_scan.hpp
+316
View File
@@ -0,0 +1,316 @@
// __ _____ _____ _____
// __| | __| | | | JSON for Modern C++
// | | |__ | | | | | | version 3.12.0
// |_____|_____|_____|_|___| https://github.com/nlohmann/json
//
// SPDX-FileCopyrightText: 2013-2026 Niels Lohmann <https://nlohmann.me>
// SPDX-FileCopyrightText: 2018-2025 The simdjson authors <https://github.com/simdjson/simdjson>
// SPDX-License-Identifier: MIT
#pragma once
#include <array> // array
#include <atomic> // atomic
#include <cstddef> // size_t
#include <cstdint> // uint8_t, uint64_t
#include <nlohmann/detail/bit_ops.hpp>
#include <nlohmann/detail/macro_scope.hpp>
// Vector code for runs of string bytes, used by the lexer for contiguous input
// (see string_bulk_run()). NEON (AArch64) and SSE2 (x86-64) belong to the
// baseline instruction sets and are used by default. The vector UTF-8 check
// needs NEON or SSSE3. SSSE3 is not part of x86-64, and the code must not
// depend on the flags of a translation unit (two translation units with
// different flags would have different definitions of the same inline
// functions): the check is compiled for SSSE3 with a function attribute and
// used where the CPU has SSSE3 (all x86-64 CPUs since about 2011), else the
// portable check. Code compiled for SSSE3 anyway (-mssse3 or more) skips the
// CPU check. JSON_NO_SIMD selects the portable code everywhere.
// NLOHMANN_JSON_NO_TARGET_ATTRIBUTE (for compilers that ignore the target
// attribute and then reject the SSSE3 intrinsics) keeps the check portable
// without disabling the SSE2 code.
#if !defined(JSON_NO_SIMD) && defined(__aarch64__) && (defined(__GNUC__) || defined(__clang__)) && defined(__BYTE_ORDER__) && defined(__ORDER_LITTLE_ENDIAN__) && __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#include <arm_neon.h>
#define JSON_SCAN_NEON 1
#else
#define JSON_SCAN_NEON 0
#endif
// (x86 only: other targets can define __SSE2__ as well, e.g., WebAssembly with -msse2, but have no <cpuid.h>)
#if !defined(JSON_NO_SIMD) && !JSON_SCAN_NEON && (defined(__x86_64__) || defined(__i386__) || defined(_M_X64) || defined(_M_IX86)) && !defined(_M_ARM64EC) && (defined(__SSE2__) || defined(_M_X64) || (defined(_M_IX86_FP) && _M_IX86_FP >= 2))
#include <emmintrin.h>
#define JSON_SCAN_SSE2 1
#else
#define JSON_SCAN_SSE2 0
#endif
#if JSON_SCAN_SSE2 && defined(__SSSE3__)
#include <tmmintrin.h>
#define JSON_SCAN_SSSE3 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
#else
#define JSON_SCAN_SSSE3 0 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
#endif
#if JSON_SCAN_SSE2 && !JSON_SCAN_SSSE3 && !defined(NLOHMANN_JSON_NO_TARGET_ATTRIBUTE) && ((defined(__clang__) && __clang_major__ >= 4) || (defined(__GNUC__) && !defined(__clang__) && (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 9)) && !defined(__cpp_modules)))
// (GCC before 4.9 has no SSSE3 intrinsics without -mssse3; GCC with C++20
// modules drops the target attribute from functions it reads from a module
// interface and then rejects the intrinsics: "needs isa option -mssse3")
#include <cpuid.h>
#include <tmmintrin.h>
#define JSON_SCAN_SSSE3_DISPATCH 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
#define JSON_SCAN_SSSE3_TARGET __attribute__((target("ssse3")))
#elif JSON_SCAN_SSE2 && !JSON_SCAN_SSSE3 && defined(_MSC_VER)
// (MSVC compiles intrinsics of any instruction set)
#include <intrin.h>
#include <tmmintrin.h>
#define JSON_SCAN_SSSE3_DISPATCH 1 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
#define JSON_SCAN_SSSE3_TARGET
#else
#define JSON_SCAN_SSSE3_DISPATCH 0 // NOLINT(cppcoreguidelines-macro-to-enum,modernize-macro-to-enum)
#define JSON_SCAN_SSSE3_TARGET
#endif
#define JSON_SCAN_VECTOR (JSON_SCAN_NEON || JSON_SCAN_SSE2)
#define JSON_SCAN_VECTOR_UTF8 (JSON_SCAN_NEON || JSON_SCAN_SSSE3 || JSON_SCAN_SSSE3_DISPATCH)
NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
{
#if JSON_SCAN_VECTOR
/*!
@brief the first byte of a string run that is a quote, a backslash, a control
character, or not ASCII, 16 bytes per step
Stops at such a byte, or where fewer than 16 bytes are left (the caller tells
the two apart). A signed compare with 0x20 finds control characters and
non-ASCII bytes at once.
*/
JSON_HEDLEY_ALWAYS_INLINE const unsigned char* vector_plain_run(const unsigned char* p, const unsigned char* e) noexcept
{
while (e - p >= 16)
{
#if JSON_SCAN_NEON
const uint8x16_t in = vld1q_u8(p);
const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))),
vcltq_s8(vreinterpretq_s8_u8(in), vdupq_n_s8(0x20)));
// one nibble per byte (the usual NEON replacement of x86's movemask, see
// D. Kutenin, "Porting x86 vector bitmask optimizations to Arm NEON", 2022)
const std::uint64_t bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
if (bits != 0)
{
return p + (count_trailing_zeros(bits) >> 2u);
}
#else
const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(p))); // NOLINT(bugprone-casting-through-void)
const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
_mm_cmplt_epi8(in, _mm_set1_epi8(0x20)));
const auto bits = static_cast<std::uint64_t>(static_cast<unsigned>(_mm_movemask_epi8(special)));
if (bits != 0)
{
return p + count_trailing_zeros(bits);
}
#endif
p += 16;
}
return p;
}
#endif
#if JSON_SCAN_VECTOR
/// vector_plain_run() for runs that are already longer than a few words:
/// inline with SSE2, out of line with NEON, where a larger string loop slows
/// down the rest of the lexer
#if JSON_SCAN_NEON
JSON_HEDLEY_NEVER_INLINE inline
#else
JSON_HEDLEY_ALWAYS_INLINE
#endif
const unsigned char* vector_plain_run_long(const unsigned char* p, const unsigned char* e) noexcept
{
return vector_plain_run(p, e);
}
#endif
#if JSON_SCAN_SSSE3_DISPATCH
/// whether the CPU has SSSE3 (CPUID leaf 1, ECX bit 9)
inline bool cpu_ssse3() noexcept
{
#if defined(_MSC_VER) && !defined(__clang__)
std::array<int, 4> regs {{}};
__cpuid(regs.data(), 1);
return (static_cast<unsigned>(regs[2]) & (1u << 9u)) != 0;
#else
unsigned eax = 0;
unsigned ebx = 0;
unsigned ecx = 0;
unsigned edx = 0;
return __get_cpuid(1, &eax, &ebx, &ecx, &edx) != 0 && (ecx & (1u << 9u)) != 0;
#endif
}
/// whether the CPU has SSSE3, asked once: the answer is kept in an atomic
/// that is initialized at compile time, so that neither a guard of a local
/// static nor a global constructor is needed (threads that ask at the same
/// time all store the same answer)
JSON_HEDLEY_ALWAYS_INLINE bool cpu_has_ssse3() noexcept
{
static std::atomic<int> known{0}; // 0: not asked yet, 1: no, 2: yes
int state = known.load(std::memory_order_relaxed);
if (JSON_HEDLEY_UNLIKELY(state == 0))
{
state = cpu_ssse3() ? 2 : 1;
known.store(state, std::memory_order_relaxed);
}
return state == 2;
}
#endif
#if JSON_SCAN_VECTOR_UTF8
/// Tables of the UTF-8 check of J. Keiser and D. Lemire, "Validating UTF-8 In
/// Less Than One Instruction Per Byte" (2021), as in simdjson ("lookup4"): each
/// maps a nibble (high and low nibble of the previous byte, high nibble of the
/// current byte) to the errors it allows; a byte pair is ill-formed if all
/// three have an error bit in common.
template<typename Dummy = void>
struct utf8_lookup4
{
static constexpr std::uint8_t too_short = 1u << 0u, too_long = 1u << 1u, overlong_3 = 1u << 2u, too_large = 1u << 3u;
static constexpr std::uint8_t surrogate = 1u << 4u, overlong_2 = 1u << 5u, too_large_1000 = 1u << 6u, overlong_4 = 1u << 6u;
static constexpr std::uint8_t two_conts = 1u << 7u, carry = too_short | too_long | two_conts;
static const std::array<std::uint8_t, 16> byte_1_high;
static const std::array<std::uint8_t, 16> byte_1_low;
static const std::array<std::uint8_t, 16> byte_2_high;
};
template<typename Dummy>
const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_1_high =
{
{
too_long, too_long, too_long, too_long, too_long, too_long, too_long, too_long,
two_conts, two_conts, two_conts, two_conts,
too_short | overlong_2, too_short, too_short | overlong_3 | surrogate, too_short | too_large | too_large_1000 | overlong_4
}
};
template<typename Dummy>
const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_1_low =
{
{
carry | overlong_3 | overlong_2 | overlong_4, carry | overlong_2, carry, carry,
carry | too_large, carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000,
carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000, carry | too_large | too_large_1000,
carry | too_large | too_large_1000, carry | too_large | too_large_1000 | surrogate, carry | too_large | too_large_1000, carry | too_large | too_large_1000
}
};
template<typename Dummy>
const std::array<std::uint8_t, 16> utf8_lookup4<Dummy>::byte_2_high =
{
{
too_short, too_short, too_short, too_short, too_short, too_short, too_short, too_short,
static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | overlong_3 | too_large_1000 | overlong_4),
static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | overlong_3 | too_large),
static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | surrogate | too_large),
static_cast<std::uint8_t>(too_long | overlong_2 | two_conts | surrogate | too_large),
too_short, too_short, too_short, too_short
}
};
/*!
@brief the run of plain string bytes and well-formed UTF-8 at p (a character
boundary), 16 bytes per step
The first quote, backslash, or control character is found with vector
compares, and the UTF-8 check of J. Keiser and D. Lemire covers the bytes up
to it. Returns true with @a block at that byte; returns false with @a block at
the start of the 16 bytes where the check found ill-formed UTF-8 or where
fewer than 16 bytes are left, for the caller to finish one sequence at a time.
Out of line, so that no constants of the check occupy registers in the
caller's loop. On x86-64, it is compiled for SSSE3 (see cpu_has_ssse3()).
*/
JSON_SCAN_SSSE3_TARGET JSON_HEDLEY_NEVER_INLINE inline bool vector_utf8_run(const unsigned char* p, const unsigned char* e, const unsigned char*& block_out) noexcept
{
using lookup = utf8_lookup4<>;
const unsigned char* block = p;
#if JSON_SCAN_NEON
const uint8x16_t t1h = vld1q_u8(lookup::byte_1_high.data());
const uint8x16_t t1l = vld1q_u8(lookup::byte_1_low.data());
const uint8x16_t t2h = vld1q_u8(lookup::byte_2_high.data());
uint8x16_t prev = vdupq_n_u8(0);
while (e - block >= 16)
{
const uint8x16_t in = vld1q_u8(block);
const uint8x16_t special = vorrq_u8(vorrq_u8(vceqq_u8(in, vdupq_n_u8('"')), vceqq_u8(in, vdupq_n_u8('\\'))), vcltq_u8(in, vdupq_n_u8(0x20)));
const uint8x16_t prev1 = vextq_u8(prev, in, 15);
const uint8x16_t sc = vandq_u8(vandq_u8(vqtbl1q_u8(t1h, vshrq_n_u8(prev1, 4)), vqtbl1q_u8(t1l, vandq_u8(prev1, vdupq_n_u8(0x0F)))), vqtbl1q_u8(t2h, vshrq_n_u8(in, 4)));
const uint8x16_t must23 = vorrq_u8(vqsubq_u8(vextq_u8(prev, in, 14), vdupq_n_u8(0xE0 - 0x80)), vqsubq_u8(vextq_u8(prev, in, 13), vdupq_n_u8(0xF0 - 0x80)));
const uint8x16_t err = veorq_u8(vandq_u8(must23, vdupq_n_u8(0x80)), sc);
const std::uint64_t special_bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(special), 4)), 0);
const std::uint64_t err_bits = vget_lane_u64(vreinterpret_u64_u8(vshrn_n_u16(vreinterpretq_u16_u8(vtstq_u8(err, err)), 4)), 0);
if (special_bits != 0)
{
// errors up to the special byte count (an incomplete sequence
// before a quote shows at the quote); the bytes after it do not
const unsigned k = static_cast<unsigned>(count_trailing_zeros(special_bits)) >> 2u;
const std::uint64_t upto = k == 15 ? ~std::uint64_t{0} :
(std::uint64_t{1} << (4u * (k + 1u))) - 1u;
if ((err_bits & upto) == 0)
{
block_out = block + k;
return true;
}
break;
}
if (err_bits != 0)
{
break;
}
prev = in;
block += 16;
}
#else
// the same with SSSE3 (pshufb for the table lookups; nibbles from 16-bit
// shifts, as there are no byte shifts)
const __m128i t1h = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_1_high.data()))); // NOLINT(bugprone-casting-through-void)
const __m128i t1l = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_1_low.data()))); // NOLINT(bugprone-casting-through-void)
const __m128i t2h = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(lookup::byte_2_high.data()))); // NOLINT(bugprone-casting-through-void)
const __m128i nibble = _mm_set1_epi8(0x0F);
const __m128i zero = _mm_setzero_si128();
__m128i prev = zero;
while (e - block >= 16)
{
const __m128i in = _mm_loadu_si128(static_cast<const __m128i*>(static_cast<const void*>(block))); // NOLINT(bugprone-casting-through-void)
const __m128i special = _mm_or_si128(_mm_or_si128(_mm_cmpeq_epi8(in, _mm_set1_epi8('"')), _mm_cmpeq_epi8(in, _mm_set1_epi8('\\'))),
_mm_cmpeq_epi8(_mm_subs_epu8(in, _mm_set1_epi8(0x1F)), zero)); // in < 0x20
const __m128i prev1 = _mm_alignr_epi8(in, prev, 15);
const __m128i sc = _mm_and_si128(_mm_and_si128(_mm_shuffle_epi8(t1h, _mm_and_si128(_mm_srli_epi16(prev1, 4), nibble)),
_mm_shuffle_epi8(t1l, _mm_and_si128(prev1, nibble))),
_mm_shuffle_epi8(t2h, _mm_and_si128(_mm_srli_epi16(in, 4), nibble)));
const __m128i must23 = _mm_or_si128(_mm_subs_epu8(_mm_alignr_epi8(in, prev, 14), _mm_set1_epi8(0xE0 - 0x80)),
_mm_subs_epu8(_mm_alignr_epi8(in, prev, 13), _mm_set1_epi8(0xF0 - 0x80)));
const __m128i err = _mm_xor_si128(_mm_and_si128(must23, _mm_set1_epi8(static_cast<char>(-128))), sc);
const auto special_bits = static_cast<unsigned>(_mm_movemask_epi8(special));
const auto err_bits = ~static_cast<unsigned>(_mm_movemask_epi8(_mm_cmpeq_epi8(err, zero))) & 0xFFFFu;
if (special_bits != 0)
{
const auto k = static_cast<unsigned>(count_trailing_zeros(static_cast<std::uint64_t>(special_bits)));
if ((err_bits & ((2u << k) - 1u)) == 0)
{
block_out = block + k;
return true;
}
break;
}
if (err_bits != 0)
{
break;
}
prev = in;
block += 16;
}
#endif
block_out = block;
return false;
}
#endif
} // namespace detail
NLOHMANN_JSON_NAMESPACE_END
include/nlohmann/detail/input/string_scan.hpp
+161 -16
View File
@@ -14,6 +14,7 @@
#include <cstring> // memcpy
#include <nlohmann/detail/bit_ops.hpp>
#include <nlohmann/detail/input/simd_scan.hpp>
#include <nlohmann/detail/macro_scope.hpp>
// Optional SIMD backend for bulk UTF-8 validation. This is an opt-in external
@@ -34,7 +35,7 @@
// This file contains the byte-level string-scanning helpers used by the lexer's
// contiguous fast path. They operate purely on raw bytes (no dependency on the
// lexer's template parameters) so they are free functions, keeping the lexer
// itself focused on the state machine; see lexer::scan_string_bulk().
// itself focused on the state machine; see lexer::get_after_string_run().
NLOHMANN_JSON_NAMESPACE_BEGIN
namespace detail
@@ -66,7 +67,7 @@ inline std::uint64_t swar_string_special(std::uint64_t v) noexcept
// return the index of the first is_string_special() byte in [data, data+n), or
// n if every byte is ordinary; scans 8 bytes at a time
inline std::size_t find_string_special(const unsigned char* data, std::size_t n) noexcept
JSON_HEDLEY_ALWAYS_INLINE std::size_t find_string_special(const unsigned char* data, std::size_t n) noexcept
{
std::size_t i = 0;
for (; i + 8 <= n; i += 8)
@@ -235,35 +236,143 @@ inline std::size_t valid_utf8_prefix(const unsigned char* data, std::size_t n) n
return pos;
}
// Scalar (C++11) computation of the bulk run length: the number of leading
// bytes in [data, data+n) that are ordinary ASCII or complete well-formed UTF-8
#if JSON_SCAN_VECTOR_UTF8
/// the end of scan_string_vector from block, where the vector loop stopped
/// (ill-formed UTF-8, or fewer than 16 bytes left): one byte or sequence at a
/// time, from the start of a sequence that crosses into the block
inline const unsigned char* scan_string_finish(const unsigned char* p, const unsigned char* block, const unsigned char* e) noexcept
{
for (int i = 1; i <= 3 && block - i >= p; ++i)
{
const unsigned char c = block[-i];
if (c < 0x80)
{
break;
}
if (c >= 0xC0)
{
const int len = 2 + static_cast<int>(c >= 0xE0) + static_cast<int>(c >= 0xF0);
if (len > i)
{
block -= i;
}
break;
}
}
for (p = block; p != e;)
{
if (*p < 0x80)
{
if (is_string_special(*p))
{
return p;
}
++p;
continue;
}
const std::size_t n = validate_one_utf8(p, static_cast<std::size_t>(e - p));
if (n == 0)
{
return p;
}
p += n;
}
return p;
}
/// the rest of a string from p (a character boundary), with the vector UTF-8
/// check and the scalar check for the end of the block where it stopped
inline const unsigned char* scan_string_vector(const unsigned char* p, const unsigned char* e) noexcept
{
const unsigned char* block = p;
if (vector_utf8_run(p, e, block))
{
return block;
}
return scan_string_finish(p, block, e);
}
#endif
#if JSON_SCAN_VECTOR
/// the end of the run of plain string characters at @a p: the first quote,
/// backslash, control character, or non-ASCII byte, or @a e. The first words
/// are checked with SWAR (one; four with NEON, where the vector mask costs
/// more), as most keys and short values end there; longer runs continue 16
/// bytes at a time.
JSON_HEDLEY_ALWAYS_INLINE const unsigned char* plain_run_end(const unsigned char* p, const unsigned char* e) noexcept
{
constexpr int prefix_words = JSON_SCAN_NEON ? 4 : 1;
for (int words = prefix_words; words > 0 && e - p >= 8; --words)
{
const std::uint64_t special = swar_string_special(read_eight_bytes(p));
if (special != 0)
{
return p + (static_cast<std::size_t>(count_trailing_zeros(special)) / 8);
}
p += 8;
}
// the vector loop only for 16 bytes or more: the serializer passes a
// string without its closing quote, so most of its runs end at e, and a
// call of the out-of-line NEON loop for a shorter rest made dump() up to
// 10% slower
if (e - p >= 16)
{
p = vector_plain_run_long(p, e);
if (e - p >= 16)
{
return p; // the vector loop stopped at a special byte
}
}
return p + find_string_special(p, static_cast<std::size_t>(e - p));
}
#endif
// Computation of the bulk run length: the number of leading bytes in
// [data, data+n) that are ordinary ASCII or complete well-formed UTF-8
// sequences, stopping before the first byte that needs individual handling (the
// closing quote, an escape, a control character, or an ill-formed/truncated
// sequence). ASCII is skipped 8 bytes at a time.
inline std::size_t scalar_string_bulk_run(const unsigned char* data, std::size_t n) noexcept
// sequence). ASCII is skipped 16 bytes at a time with SSE2 and 8 bytes at a
// time otherwise; runs of non-ASCII text use the vector UTF-8 check where
// available.
JSON_HEDLEY_ALWAYS_INLINE std::size_t scalar_string_bulk_run(const unsigned char* data, std::size_t n) noexcept
{
std::size_t pos = 0;
while (pos < n)
const unsigned char* const e = data + n;
const unsigned char* p = data;
while (p != e)
{
pos += find_string_special(data + pos, n - pos);
if (pos >= n || data[pos] < 0x80u)
#if JSON_SCAN_VECTOR
p = plain_run_end(p, e);
#else
p += find_string_special(p, static_cast<std::size_t>(e - p));
#endif
if (p == e || *p < 0x80u)
{
break; // end of buffer, or a quote/escape/control byte
}
#if JSON_SCAN_VECTOR_UTF8
#if JSON_SCAN_SSSE3_DISPATCH
if (JSON_HEDLEY_LIKELY(cpu_has_ssse3()))
#endif
{
return static_cast<std::size_t>(scan_string_vector(p, e) - data);
}
#endif
#if !JSON_SCAN_VECTOR_UTF8 || JSON_SCAN_SSSE3_DISPATCH
// a run of multi-byte sequences (e.g. CJK text) is validated sequence
// by sequence without searching for the next special byte in between
do
{
const std::size_t seq = validate_one_utf8(data + pos, n - pos);
const std::size_t seq = validate_one_utf8(p, static_cast<std::size_t>(e - p));
if (seq == 0)
{
return pos; // ill-formed or truncated: let the byte path diagnose it
return static_cast<std::size_t>(p - data); // ill-formed or truncated: let the byte path diagnose it
}
pos += seq;
p += seq;
}
while (pos < n && data[pos] >= 0x80u);
while (p != e && *p >= 0x80u);
#endif
}
return pos;
return static_cast<std::size_t>(p - data);
}
#if defined(JSON_USE_SIMDUTF) && defined(JSON_HAS_CPP_17)
@@ -304,7 +413,7 @@ inline std::size_t find_string_delimiter(const unsigned char* data, std::size_t
// next delimiter is validated in one shot by simdutf; on the rare failure the
// scalar helper recomputes the exact valid prefix so the byte path still
// produces the precise diagnostic. Without it, the pure scalar path is used.
inline std::size_t string_bulk_run(const unsigned char* data, std::size_t n) noexcept
JSON_HEDLEY_ALWAYS_INLINE std::size_t string_bulk_run(const unsigned char* data, std::size_t n) noexcept
{
#if defined(JSON_USE_SIMDUTF) && defined(JSON_HAS_CPP_17)
const std::size_t run = find_string_delimiter(data, n);
@@ -316,6 +425,42 @@ inline std::size_t string_bulk_run(const unsigned char* data, std::size_t n) noe
return scalar_string_bulk_run(data, n);
}
#if JSON_SCAN_NEON && !(defined(JSON_USE_SIMDUTF) && defined(JSON_HAS_CPP_17))
/// scalar_string_bulk_run() from @a start on, out of line (see
/// lexer_string_bulk_run())
JSON_HEDLEY_NEVER_INLINE inline std::size_t string_bulk_run_from(const unsigned char* data, std::size_t start, std::size_t n) noexcept
{
return start + scalar_string_bulk_run(data + start, n - start);
}
#endif
// string_bulk_run() for the lexer. With NEON, only the first four words are
// checked inline (most keys and short values end there), and longer runs and
// non-ASCII text continue out of line. The lexer's scan function runs once per
// token, and the vector code inlined into it needs more registers, which every
// token pays for: 5% of json::accept() on jeopardy.json with Apple Clang on
// Apple M1, even though no string of that file reaches the vector code. The
// serializer keeps string_bulk_run() inline, which is faster there.
JSON_HEDLEY_ALWAYS_INLINE std::size_t lexer_string_bulk_run(const unsigned char* data, std::size_t n) noexcept
{
#if JSON_SCAN_NEON && !(defined(JSON_USE_SIMDUTF) && defined(JSON_HAS_CPP_17))
std::size_t i = 0;
for (int words = 4; words > 0 && n - i >= 8; --words)
{
const std::uint64_t special = swar_string_special(read_eight_bytes(data + i));
if (special != 0)
{
const std::size_t pos = i + (static_cast<std::size_t>(count_trailing_zeros(special)) / 8);
return data[pos] < 0x80u ? pos : string_bulk_run_from(data, pos, n);
}
i += 8;
}
return string_bulk_run_from(data, i, n);
#else
return string_bulk_run(data, n);
#endif
}
// Decode the 4 hex digits at [data, data+4) - the digits following a `\u`
// escape - into a codepoint 0x0000..0xFFFF via one table lookup per byte
// (after yyjson's read_hex_u16), or return -1 if any of the 4 bytes is not a
Loaded 100 of 186 files, more files were not shown because too many files have changed in this diff. Show more