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Author SHA1 Message Date
Niels Lohmann c6c0a6d4e8 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann 0cab7704fc Regenerate the amalgamated headers
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:23 +02:00
Niels Lohmann 2cf1b977aa 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann ad38486303 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann 5a7968a1d0 Avoid GCC useless-cast warnings in the integer index tests
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:23 +02:00
Niels Lohmann bc5d1d6162 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann 6ae3f381f1 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann b84f751e28 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann bf3664f18e 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann a24600c61d 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann 37b72746e2 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann 5c0e929b41 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann d366489a83 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>
2026-10-13 22:22:23 +02:00
Niels Lohmann 24b3df9eb9 Regenerate the amalgamated headers
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:22 +02:00
Niels Lohmann 22002c8baa 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann a5271fcbc3 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann a3efb320b6 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann df3dc50de9 Make max_input_size a function (GCC -Wunused-const-variable)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:22 +02:00
Niels Lohmann b1a121e83d Check the steps of the deep-nesting test separately
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:22 +02:00
Niels Lohmann 921ad3ecd8 Suppress Flawfinder's read() finding on the deleted overload
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:22 +02:00
Niels Lohmann de3513f585 Annotate intentional patterns in unit-json_view.cpp for clang-tidy
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:22 +02:00
Niels Lohmann 2e9181f3fa Fix clang-tidy findings in unit-json_view_builder.cpp
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:22 +02:00
Niels Lohmann b425e9f76d Give document_data a user-provided constructor
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:22 +02:00
Niels Lohmann a107bfd4c2 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann 3ea4b9258a Align the banner comment of json_view.hpp
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:22 +02:00
Niels Lohmann a1deab58fd 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann 84fbe1d017 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann 6b3580ad0c 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann 2c42c8328b 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann 3f4c81a44f 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann f535edfea4 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann 1a9daa7363 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann dab41d22cf 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann 8ac3352e97 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann c6c422d7e3 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann 47b7a05b9d 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>
2026-10-13 22:22:22 +02:00
Niels Lohmann b177f48df5 Regenerate the amalgamated headers
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:21 +02:00
Niels Lohmann ecd9ae2d87 Silence MSVC C4127 for a platform-constant check in the to_chars test
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:21 +02:00
Niels Lohmann a403eb45b3 Credit Zmij's authors in to_chars.hpp, the README, and the license page
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:21 +02:00
Niels Lohmann da84d2a513 Select the Zmij conversion by a trait, not by the double overload
The non-template overloads for double asserted binary64 doubles wherever json.hpp was included, so the library no longer compiled where double is not IEEE 754 binary64 (AVR, -fshort-double). A trait now picks Zmij for any binary64 type, including a long double of that format (MSVC, Apple Arm), and Grisu2 for the others. Remove the unused write_short_decimal, powers_of_ten_16, zmij::decimal, zmij::to_decimal, and shortest_digits(double).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:21 +02:00
Niels Lohmann 658605bc7a Fix CI findings in the Zmij writer and its tests
- bit_ops.hpp: include macro_scope.hpp (JSON_HEDLEY_ALWAYS_INLINE); fixes IWYU
- to_chars.hpp: C4100 for the unused parameter in release builds, clang-tidy
  sign comparison, cpplint runtime/int, GCC -Wstrict-overflow (unsigned abs)
- unit-to_chars.cpp: parse with the library instead of strtod (MinGW's strtod
  rounds some 16/17 digit inputs wrongly); no floating-point std::to_chars
  with icpc

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:21 +02:00
Niels Lohmann 32092c79a5 Write doubles with the shortest digits (Żmij), digits in registers
Write doubles with the conversion of Zmij by Victor Zverovich (MIT),
ported to C++11 (detail/conversions/zmij.hpp). It finds the
shortest decimal that reads back as the same double, and the
closest one if there are several. Grisu2, used until now, is fast
but not always shortest: it sometimes writes a 17th digit where 16
suffice, or a last digit that is not the closest. The layout is
unchanged (1.5, 100.0, 1e+100, -0.0); float keeps Grisu2.

Digits are converted eight at a time with the BCD conversion of
Xiang JunBo, as in Zmij, and written with one byte swap per eight
digits and fixed-size moves instead of per-digit loops. Leading and
trailing zeros are counted from those bytes. to_chars() uses a
local buffer when the caller's is shorter than the 41 bytes this
may write. The powers of ten come from the number-parsing table,
adjusted where it holds values rounded up, and extended with Zmij's
compressed tables beyond 10^308.

write_shortest() converts its 16 digits in one vector register
(SSE2 on x86-64, NEON on 64-bit Arm, both baseline) and inserts the
decimal point inside the register, avoiding a store-forwarding
stall that cost about 25% of the time to write a double. dump()
writes floats and integers straight into the serializer's write
buffer instead of copying them from a member buffer, and small
integers eight digits at a time. read_eight_bytes() and
parse_eight_digits() are marked always-inline, which GCC had been
calling out of line in the number-parsing loops.

Of one million random doubles, about 0.14% are now written with
different digits, always to a value that still reads back as the
same double.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:21 +02:00
Niels Lohmann af711143a0 Use data() instead of c_str() in the multi-byte decimal point path
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
Niels Lohmann a9b0e6b843 Address review: std::any_of in has_nonzero_digit, comment punctuation
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
Niels Lohmann 4a28e684ea Drop the position updates in the bulk \u path, which #5809 made unused
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
Niels Lohmann b0053eec5a Regenerate the amalgamated headers
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
Niels Lohmann 7f3063b974 Mark the unsigned long of the MSVC bit scans for cpplint
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
Niels Lohmann 92e8448c52 Fix clang-tidy 22 findings in unit-class_lexer.cpp
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
Niels Lohmann aab407de27 Reword float conversion notes for the string type and number_float_t docs
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
Niels Lohmann 802a59a14b Load string scan words with memcpy and use MSVC bit-scan intrinsics
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
Niels Lohmann 7b6a9e8e3a Fix CI warnings in own float parser
- pow5_table.hpp: pow5_128_largest_power was unused in this branch's
  own code (GCC -Werror=unused-const-variable); tie it to the table
  size with a static_assert instead of removing it, since a later
  branch in the stack (json-view/23-zmij) uses it.
- number_parse.hpp: rename the local variable `copy` to `buffer` to
  satisfy cpplint's build/include_what_you_use check.
- unit-class_lexer.cpp: extend the NOLINT list on the seeded mt19937
  with bugprone-random-generator-seed, and parenthesize
  `8 * sizeof(Bits) - 1` for clang-tidy.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
Niels Lohmann b5aa90a301 Speed up the lexer: own float parser, string scan, and \u table
Give the library its own correctly rounded float converter for
binary32 and binary64 (IEEE 754), and speed up the lexer's string
and escape scanning.

The converter splits a number token into sign, significand, and
decimal exponent, then tries Clinger's fast path, then a templated
Eisel-Lemire step, and falls back to an exact big-integer digit
comparison for tokens with more than 19 significant digits whose two
candidate values round differently. This replaces std::from_chars
and strtod/strtof for both formats, so parsed values no longer
depend on the C/C++ library or the current locale. The strtold
fallback kept for other long double formats (x87, binary128) now
also copies a multi-byte decimal point correctly, fixing #5660.
eisel_lemire() and decimal_to_float() are always inlined so callers
keep the whole conversion in their hot loop.

The string-scanning kernels in string_scan.hpp find a stop byte with
the trailing-zero count of the SWAR mask instead of a byte loop, and
scalar_string_bulk_run() validates a run of multi-byte UTF-8
sequences one after another instead of re-searching after each one.

get_codepoint() decodes a contiguous \uXXXX escape with one table
lookup per byte instead of four range-checked get() calls; the
streaming path and all error positions are unchanged.

Adds 508 generated hard float-parsing cases with expected binary32
and binary64 bits, and kernel-comparison tests for the string scans
and the escape table against byte-by-byte references.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 22:22:20 +02:00
308 changed files with 6482 additions and 602025 deletions

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+3 -10
View File
@@ -108,16 +108,9 @@ The tests are located in [`tests/src/unit-*.cpp`](https://github.com/nlohmann/js
are structured along the features of the library or the nature of the tests. Usually, it should be clear from the
context which existing file needs to be extended, and only very few cases require creating new test files.
When fixing a bug, edit `unit-regression3.cpp` and add a section referencing the fixed issue. Tests that need C++17 or
C++20 go into `unit-regression3-cpp17.cpp` or `unit-regression3-cpp20.cpp` instead, so the large file is not rebuilt
for every C++ standard. `unit-regression2.cpp` holds the older tests; the two files exist because a single one grew
large enough for the MinGW linker to fail relocating it, so please keep adding to the smaller file rather than growing
the larger one.
To keep compile times down, several test files are compiled together as one translation unit. This sets a few rules
for test files, such as giving file-scope helpers file-specific names. See the README in the
[`tests`](https://github.com/nlohmann/json/tree/develop/tests) folder for how the tests are built and what to keep in
mind when adding them.
When fixing a bug, edit `unit-regression3.cpp` and add a section referencing the fixed issue.
`unit-regression2.cpp` holds the older tests; the two files exist because a single one grew large enough for the
MinGW linker to fail relocating it, so please keep adding to the smaller file rather than growing the larger one.
#### Exceptions
+3 -4
View File
@@ -62,13 +62,12 @@ labels:
- "include/nlohmann/detail/view/.*"
- "single_include/nlohmann/json_view\\.hpp"
- "tests/src/unit-json_view.*"
- "tests/src/json_view_test_helpers\\.hpp"
- "tests/src/fuzzer-(parse_json_view|json_view_image)\\.cpp"
- "tests/src/fuzzer-parse_json_view\\.cpp"
- "tools/amalgamate/config_json_view\\.json"
- "docs/mkdocs/docs/features/json_view\\.md"
- "docs/mkdocs/docs/api/basic_json_(document|view)/.*"
- "docs/mkdocs/docs/api/(ordered_)?json_(editable_)?(document|view)\\.md"
- "docs/mkdocs/docs/examples/(basic_json_(document|view)__|(ordered_)?json_(editable_)?(document|view)).*"
- "docs/mkdocs/docs/api/(ordered_)?json_(document|view)\\.md"
- "docs/mkdocs/docs/examples/(basic_json_(document|view)__|(ordered_)?json_(document|view)).*"
- "tests/benchmarks/src/benchmarks_view\\.cpp"
- label: "aspect: json_view"
+1 -1
View File
@@ -28,7 +28,7 @@ jobs:
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
+20 -19
View File
@@ -22,7 +22,7 @@ jobs:
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
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@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
- uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
with:
name: pr
path: pr/
check:
runs-on: ubuntu-26.04
runs-on: ubuntu-latest
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@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
@@ -77,12 +77,13 @@ jobs:
cd $MAIN_DIR
# Built from this PR's own tools/macro_builder/main.cpp, not a
# develop checkout: unlike amalgamate.py, this tool has no other
# source of truth to check against (its own README documents that
# it must reproduce macro_scope.hpp byte for byte), so there is
# nothing to gain from checking out a separate copy, and doing so
# would make this step fail on a PR that adds support for a new
# dispatch table until that PR itself merges to develop.
# develop checkout: unlike amalgamate.py and generate_natvis.py,
# this tool has no other source of truth to check against (its
# own README documents that it must reproduce macro_scope.hpp
# byte for byte), so there is nothing to gain from checking out a
# separate copy, and doing so would make this step fail on a PR
# that adds support for a new dispatch table until that PR itself
# merges to develop.
TMPDIR=$(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"
@@ -145,14 +146,14 @@ jobs:
- name: Regenerate nlohmann_json.natvis
run: |
cd $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
# 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
- name: Build patch and check for differences
id: diff
@@ -172,7 +173,7 @@ jobs:
# instead of installing the pinned astyle version locally.
- name: Upload patch
if: steps.diff.outputs.has_diff == 'true'
uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
with:
name: amalgamation-patch
path: patch/amalgamation.patch
+1 -1
View File
@@ -20,7 +20,7 @@ jobs:
timeout-minutes: 30
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
+2 -2
View File
@@ -13,7 +13,7 @@ jobs:
runs-on: ubuntu-22.04
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
@@ -35,7 +35,7 @@ jobs:
dry-run: false
language: c++
- name: Upload Crash
uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
if: failure() && steps.build.outcome == 'success'
with:
name: artifacts
+5 -5
View File
@@ -21,13 +21,13 @@ permissions:
jobs:
CodeQL-Build:
runs-on: ubuntu-26.04
runs-on: ubuntu-latest
permissions:
security-events: write
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
@@ -38,14 +38,14 @@ jobs:
# Initializes the CodeQL tools for scanning.
- name: Initialize CodeQL
uses: github/codeql-action/init@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
uses: github/codeql-action/init@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
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@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
uses: github/codeql-action/autobuild@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
- name: Perform CodeQL Analysis
uses: github/codeql-action/analyze@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
uses: github/codeql-action/analyze@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
@@ -20,7 +20,7 @@ jobs:
pull-requests: write
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
+1 -1
View File
@@ -21,7 +21,7 @@ jobs:
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
+2 -2
View File
@@ -31,7 +31,7 @@ jobs:
security-events: write
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
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@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
with:
sarif_file: ${{github.workspace}}/flawfinder_results.sarif
+1 -1
View File
@@ -23,7 +23,7 @@ jobs:
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
+1 -1
View File
@@ -37,7 +37,7 @@ jobs:
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
+4 -4
View File
@@ -40,7 +40,7 @@ jobs:
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
@@ -50,7 +50,7 @@ jobs:
persist-credentials: false
- name: "Run analysis"
uses: ossf/scorecard-action@fa7117db83c52d787ae5a89f350999701505d78e # v2.5.0
uses: ossf/scorecard-action@2d1146689b8cda280b9bc96326124645441f03bc # v2.4.4
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@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
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@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
with:
sarif_file: results.sarif
+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-26.04
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
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@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
uses: github/codeql-action/upload-sarif@2892aa5e19bbd11bc0cff5427e3b750a04d9e3c2 # v4.38.2
with:
sarif_file: semgrep.sarif
if: always()
+1 -1
View File
@@ -16,7 +16,7 @@ jobs:
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
+32 -32
View File
@@ -25,20 +25,20 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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-26.04
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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-26.04
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
@@ -92,27 +92,27 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
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-26.04
runs-on: ubuntu-latest
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@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
@@ -123,7 +123,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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-26.04
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
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@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
with:
name: code-coverage-report
path: ${{ github.workspace }}/build/html
@@ -244,7 +244,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Run CMake
run: CXX=g++-${{ 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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-26.04
runs-on: ubuntu-latest
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
with:
egress-policy: audit
@@ -443,20 +443,20 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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-26.04
runs-on: ubuntu-latest
strategy:
matrix:
target: [ci_test_examples, ci_test_build_documentation, ci_test_documentation_mermaid]
steps:
- name: Harden Runner
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
uses: step-security/harden-runner@e14015d583714f6e62063499dc959a02595150a1 # v2.21.1
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: ${{ matrix.target == 'ci_test_build_documentation' && '0' || '1' }}
- uses: actions/setup-node@949feb2413d6458794dcd2491c4babbbce0c15c1 # v7.1.0
- uses: actions/setup-node@820762786026740c76f36085b0efc47a31fe5020 # v7.0.0
if: matrix.target == 'ci_test_documentation_mermaid'
with:
node-version: 24
@@ -484,7 +484,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- name: Check that the job runs natively on arm64
run: uname -m && test "$(uname -m)" = aarch64
- name: Run CMake
+10 -12
View File
@@ -90,7 +90,7 @@ jobs:
with:
persist-credentials: false
- name: Get latest CMake and ninja
uses: lukka/get-cmake@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
- 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)
@@ -166,21 +166,19 @@ 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.
# 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.
# 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.
- 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="-fuse-ld=lld -lwinpthread" ^
-DCMAKE_EXE_LINKER_FLAGS="-lwinpthread" ^
-G"MinGW Makefiles" ^
-DCMAKE_BUILD_TYPE=Debug ^
-DJSON_BuildTests=On
@@ -216,7 +214,7 @@ 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@a89e43e22a96abafcd7a62db652a65ecd33052c9 # v4.4.4
uses: lukka/get-cmake@fffaaafeea488556c2c12dad60690008bc1caacb # v4.4.2
with:
cmakeVersion: 4.3.4
# CMAKE_CXX_FLAGS replaces CMake's MSVC defaults (which include /EHsc), and
-3
View File
@@ -60,6 +60,3 @@ MODULE.bazel.lock
/json.tar.xz.asc
/release_files/
/single_include/nlohmann/*.asc
# GCC module cache
/gcm.cache/
-4
View File
@@ -1,7 +1,6 @@
{
"_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": [
@@ -11,8 +10,5 @@
"PULSE_UNNECESSARY_COPY_OPTIONAL",
"PULSE_RESOURCE_LEAK",
"PULSE_CONST_REFABLE"
],
"report-block-list-path-regex": [
"tests/src/unit-json_view.*\\.cpp"
]
}
-7
View File
@@ -68,12 +68,8 @@ cc_library(
"include/nlohmann/detail/string_utils.hpp",
"include/nlohmann/detail/value_t.hpp",
"include/nlohmann/detail/view/builder.hpp",
"include/nlohmann/detail/view/compare.hpp",
"include/nlohmann/detail/view/document_data.hpp",
"include/nlohmann/detail/view/edit.hpp",
"include/nlohmann/detail/view/edit_storage.hpp",
"include/nlohmann/detail/view/errors.hpp",
"include/nlohmann/detail/view/image.hpp",
"include/nlohmann/detail/view/input.hpp",
"include/nlohmann/detail/view/iterator.hpp",
"include/nlohmann/detail/view/lookup.hpp",
@@ -82,11 +78,8 @@ cc_library(
"include/nlohmann/detail/view/materialize.hpp",
"include/nlohmann/detail/view/node.hpp",
"include/nlohmann/detail/view/number.hpp",
"include/nlohmann/detail/view/object_index.hpp",
"include/nlohmann/detail/view/pointer.hpp",
"include/nlohmann/detail/view/scan.hpp",
"include/nlohmann/detail/view/serializer.hpp",
"include/nlohmann/detail/view/simd.hpp",
"include/nlohmann/detail/view/string_ref.hpp",
"include/nlohmann/detail/view/value.hpp",
"include/nlohmann/json.hpp",
+13 -26
View File
@@ -116,7 +116,7 @@ There is also a [**docset**](https://github.com/Kapeli/Dash-User-Contributions/t
- **Constructors**: [basic_json](https://json.nlohmann.me/api/basic_json/basic_json), [array](https://json.nlohmann.me/api/basic_json/array), [binary](https://json.nlohmann.me/api/basic_json/binary), [object](https://json.nlohmann.me/api/basic_json/object)
- **Object inspection**: [type](https://json.nlohmann.me/api/basic_json/type), [operator value_t](https://json.nlohmann.me/api/basic_json/operator_value_t), [type_name](https://json.nlohmann.me/api/basic_json/type_name), [is_primitive](https://json.nlohmann.me/api/basic_json/is_primitive), [is_structured](https://json.nlohmann.me/api/basic_json/is_structured), [is_null](https://json.nlohmann.me/api/basic_json/is_null), [is_boolean](https://json.nlohmann.me/api/basic_json/is_boolean), [is_number](https://json.nlohmann.me/api/basic_json/is_number), [is_number_integer](https://json.nlohmann.me/api/basic_json/is_number_integer), [is_number_unsigned](https://json.nlohmann.me/api/basic_json/is_number_unsigned), [is_number_float](https://json.nlohmann.me/api/basic_json/is_number_float), [is_object](https://json.nlohmann.me/api/basic_json/is_object), [is_array](https://json.nlohmann.me/api/basic_json/is_array), [is_string](https://json.nlohmann.me/api/basic_json/is_string), [is_binary](https://json.nlohmann.me/api/basic_json/is_binary), [is_discarded](https://json.nlohmann.me/api/basic_json/is_discarded)
- **Value access**: [get](https://json.nlohmann.me/api/basic_json/get), [get_to](https://json.nlohmann.me/api/basic_json/get_to), [get_ptr](https://json.nlohmann.me/api/basic_json/get_ptr), [get_ref](https://json.nlohmann.me/api/basic_json/get_ref), [operator ValueType](https://json.nlohmann.me/api/basic_json/operator_ValueType), [get_binary](https://json.nlohmann.me/api/basic_json/get_binary)
- **Element access**: [at](https://json.nlohmann.me/api/basic_json/at), [operator[]](https://json.nlohmann.me/api/basic_json/operator%5B%5D/), [value](https://json.nlohmann.me/api/basic_json/value), [front](https://json.nlohmann.me/api/basic_json/front), [back](https://json.nlohmann.me/api/basic_json/back)
- **Element access**: [at](https://json.nlohmann.me/api/basic_json/at), [operator[]](https://json.nlohmann.me/api/basic_json/operator[]), [value](https://json.nlohmann.me/api/basic_json/value), [front](https://json.nlohmann.me/api/basic_json/front), [back](https://json.nlohmann.me/api/basic_json/back)
- **Lookup**: [find](https://json.nlohmann.me/api/basic_json/find), [count](https://json.nlohmann.me/api/basic_json/count), [contains](https://json.nlohmann.me/api/basic_json/contains)
- **Iterators**: [begin](https://json.nlohmann.me/api/basic_json/begin), [cbegin](https://json.nlohmann.me/api/basic_json/cbegin), [end](https://json.nlohmann.me/api/basic_json/end), [cend](https://json.nlohmann.me/api/basic_json/cend), [rbegin](https://json.nlohmann.me/api/basic_json/rbegin), [rend](https://json.nlohmann.me/api/basic_json/rend), [crbegin](https://json.nlohmann.me/api/basic_json/crbegin), [crend](https://json.nlohmann.me/api/basic_json/crend), [items](https://json.nlohmann.me/api/basic_json/items)
- **Capacity**: [empty](https://json.nlohmann.me/api/basic_json/empty), [size](https://json.nlohmann.me/api/basic_json/size), [max_size](https://json.nlohmann.me/api/basic_json/max_size)
@@ -125,7 +125,7 @@ There is also a [**docset**](https://github.com/Kapeli/Dash-User-Contributions/t
- **Serialization / Dumping**: [dump](https://json.nlohmann.me/api/basic_json/dump)
- **Deserialization / Parsing**: [parse](https://json.nlohmann.me/api/basic_json/parse), [accept](https://json.nlohmann.me/api/basic_json/accept), [sax_parse](https://json.nlohmann.me/api/basic_json/sax_parse)
- **JSON Pointer functions**: [flatten](https://json.nlohmann.me/api/basic_json/flatten), [unflatten](https://json.nlohmann.me/api/basic_json/unflatten)
- **JSON Patch functions**: [patch](https://json.nlohmann.me/api/basic_json/patch), [patch_inplace](https://json.nlohmann.me/api/basic_json/patch_inplace), [diff](https://json.nlohmann.me/api/basic_json/diff), [merge_patch](https://json.nlohmann.me/api/basic_json/merge_patch), [merge_diff](https://json.nlohmann.me/api/basic_json/merge_diff)
- **JSON Patch functions**: [patch](https://json.nlohmann.me/api/basic_json/patch), [patch_inplace](https://json.nlohmann.me/api/basic_json/patch_inplace), [diff](https://json.nlohmann.me/api/basic_json/diff), [merge_patch](https://json.nlohmann.me/api/basic_json/merge_patch)
- **Static functions**: [meta](https://json.nlohmann.me/api/basic_json/meta), [get_allocator](https://json.nlohmann.me/api/basic_json/get_allocator)
- **Binary formats**: [from_bjdata](https://json.nlohmann.me/api/basic_json/from_bjdata), [from_bon8](https://json.nlohmann.me/api/basic_json/from_bon8), [from_bson](https://json.nlohmann.me/api/basic_json/from_bson), [from_cbor](https://json.nlohmann.me/api/basic_json/from_cbor), [from_msgpack](https://json.nlohmann.me/api/basic_json/from_msgpack), [from_ubjson](https://json.nlohmann.me/api/basic_json/from_ubjson), [to_bjdata](https://json.nlohmann.me/api/basic_json/to_bjdata), [to_bon8](https://json.nlohmann.me/api/basic_json/to_bon8), [to_bson](https://json.nlohmann.me/api/basic_json/to_bson), [to_cbor](https://json.nlohmann.me/api/basic_json/to_cbor), [to_msgpack](https://json.nlohmann.me/api/basic_json/to_msgpack), [to_ubjson](https://json.nlohmann.me/api/basic_json/to_ubjson)
- **Non-member functions**: [operator<<](https://json.nlohmann.me/api/operator_ltlt/), [operator>>](https://json.nlohmann.me/api/operator_gtgt/), [to_string](https://json.nlohmann.me/api/basic_json/to_string)
@@ -360,7 +360,7 @@ std::cout << cpp_string << " == " << cpp_string2 << " == " << j_string.get<std::
std::cout << j_string << " == " << serialized_string << std::endl;
```
[`.dump()`](https://json.nlohmann.me/api/basic_json/dump/) returns the serialized JSON text, so a string value is enclosed in quotes and special characters are escaped. Use [`get<std::string>()`](https://json.nlohmann.me/api/basic_json/get/) to retrieve the originally stored string value.
[`.dump()`](https://json.nlohmann.me/api/basic_json/dump/) returns the originally stored string value.
Note the library only supports UTF-8. When you store strings with different encodings in the library, calling [`dump()`](https://json.nlohmann.me/api/basic_json/dump/) may throw an exception unless `json::error_handler_t::replace`, `json::error_handler_t::ignore`, or `json::error_handler_t::keep` are used as error handlers.
@@ -687,15 +687,15 @@ json j_result = j_original.patch(j_patch);
// calculate a JSON patch from two JSON values
json::diff(j_result, j_original);
// [
// { "op": "replace", "path": "/baz", "value": ["one", "two", "three"] },
// { "op": "remove", "path": "/hello" },
// { "op":" replace", "path": "/baz", "value": ["one", "two", "three"] },
// { "op": "remove","path": "/hello" },
// { "op": "add", "path": "/foo", "value": "bar" }
// ]
```
### JSON Merge Patch
The library supports **JSON Merge Patch** ([RFC 7396](https://tools.ietf.org/html/rfc7396)) as a patch format. Instead of using JSON Pointer (see above) to specify values to be manipulated, it describes the changes using a syntax that closely mimics the document being modified.
The library supports **JSON Merge Patch** ([RFC 7386](https://tools.ietf.org/html/rfc7386)) as a patch format. Instead of using JSON Pointer (see above) to specify values to be manipulated, it describes the changes using a syntax that closely mimics the document being modified.
```cpp
// a JSON value
@@ -725,20 +725,6 @@ j_document.merge_patch(j_patch);
// }
```
Conversely, [`merge_diff`](https://json.nlohmann.me/api/basic_json/merge_diff/) creates a merge patch from two JSON values:
```cpp
// create a merge patch that turns j_original into j_document
json j_original = R"({"a": "b", "c": {"d": "e", "f": "g"}})"_json;
json::merge_diff(j_original, j_document);
// {
// "a": "z",
// "c": {
// "f": null
// }
// }
```
### Implicit conversions
Supported types can be implicitly converted to JSON values.
@@ -1288,9 +1274,13 @@ The package configuration file, `nlohmann_jsonConfig.cmake`, can be used either
To embed the library directly into an existing CMake project, place the entire source tree in a subdirectory and call `add_subdirectory()` in your `CMakeLists.txt` file:
```cmake
# Typically you don't care so much for a third party library's tests to be
# run from your own project's code.
set(JSON_BuildTests OFF CACHE INTERNAL "")
# If you only include this third party in PRIVATE source files, you do not
# need to install it when your main project gets installed.
set(JSON_Install OFF CACHE INTERNAL "")
# set(JSON_Install OFF CACHE INTERNAL "")
# Don't use include(nlohmann_json/CMakeLists.txt) since that carries with it
# unintended consequences that will break the build. It's generally
@@ -1305,8 +1295,8 @@ target_link_libraries(foo PRIVATE nlohmann_json::nlohmann_json)
##### Embedded (FetchContent)
Since CMake v3.14,
[FetchContent](https://cmake.org/cmake/help/v3.14/module/FetchContent.html) can
Since CMake v3.11,
[FetchContent](https://cmake.org/cmake/help/v3.11/module/FetchContent.html) can
be used to automatically download a release as a dependency at configure time.
Example:
@@ -1371,9 +1361,7 @@ Use your favorite [**package manager**](https://json.nlohmann.me/integration/pac
- <img src="https://raw.githubusercontent.com/nlohmann/json/refs/heads/develop/docs/mkdocs/docs/images/package_managers/swift.svg" height="20">&nbsp;[**Swift Package Manager**](https://json.nlohmann.me/integration/package_managers/#swift-package-manager) `nlohmann/json`
- <img src="https://raw.githubusercontent.com/nlohmann/json/refs/heads/develop/docs/mkdocs/docs/images/package_managers/nuget.svg" height="20">&nbsp;[**Nuget**](https://json.nlohmann.me/integration/package_managers/#nuget) `nlohmann.json`
- <img src="https://raw.githubusercontent.com/nlohmann/json/refs/heads/develop/docs/mkdocs/docs/images/package_managers/conda.svg" height="20">&nbsp;[**Conda**](https://json.nlohmann.me/integration/package_managers/#conda) `nlohmann_json`
- [**MSYS2**](https://json.nlohmann.me/integration/package_managers/#msys2) `mingw-w64-nlohmann-json`
- <img src="https://raw.githubusercontent.com/nlohmann/json/refs/heads/develop/docs/mkdocs/docs/images/package_managers/macports.svg" height="20">&nbsp;[**MacPorts**](https://json.nlohmann.me/integration/package_managers/#macports) `nlohmann-json`
- [**build2**](https://json.nlohmann.me/integration/package_managers/#build2) `nlohmann-json`
- <img src="https://raw.githubusercontent.com/nlohmann/json/refs/heads/develop/docs/mkdocs/docs/images/package_managers/CPM.png" height="20">&nbsp;[**cpm.cmake**](https://json.nlohmann.me/integration/package_managers/#cpmcmake) `gh:nlohmann/json`
- <img src="https://raw.githubusercontent.com/nlohmann/json/refs/heads/develop/docs/mkdocs/docs/images/package_managers/xmake.svg" height="20">&nbsp;[**xmake**](https://json.nlohmann.me/integration/package_managers/#xmake) `nlohmann_json`
@@ -1410,7 +1398,6 @@ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR I
- The class contains parts of [Google Abseil](https://github.com/abseil/abseil-cpp) which is licensed under the [Apache 2.0 License](https://opensource.org/licenses/Apache-2.0).
- The class contains an adapted version of the Eisel-Lemire algorithm, its table of powers of five, and its digit comparison for long numbers from [fast_float](https://github.com/fastfloat/fast_float) by Daniel Lemire and contributors, which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here), the Apache 2.0 License, and the Boost Software License. Copyright &copy; 2021 The fast_float authors
- The view's parser (`<nlohmann/json_view.hpp>`) contains techniques and code adapted from [yyjson](https://github.com/ibireme/yyjson) by YaoYuan, which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above): table-driven decoding of `\u` escapes and fixed-offset unrolled checks.
- The view's parser (`<nlohmann/json_view.hpp>`) validates non-ASCII strings with the vector UTF-8 check of [simdjson](https://github.com/simdjson/simdjson) by Daniel Lemire, Geoff Langdale, John Keiser, and contributors (its "lookup4" algorithm and tables, after J. Keiser and D. Lemire, "Validating UTF-8 In Less Than One Instruction Per Byte", 2021), which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here) and the Apache 2.0 License. Copyright &copy; 2018-2025 The simdjson authors
<img align="right" src="https://git.fsfe.org/reuse/reuse-ci/raw/branch/master/reuse-horizontal.png" alt="REUSE Software">
+7 -14
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 --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 ${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 ${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 --ignore-errors inconsistent 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
COMMENT "Compile and test with coverage"
)
@@ -488,13 +488,6 @@ 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
@@ -503,7 +496,7 @@ 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 ${N} --include=default_defines.hpp
--include=${CMAKE_BINARY_DIR}/cppcheck_feature_tests.hpp --cppcheck-build-dir=cppcheck
--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"
@@ -890,11 +883,11 @@ add_custom_target(ci_icpx
# The following tests are excluded as they trigger known nvc++ 25.5 defects (not
# library bugs); see https://github.com/nlohmann/json for tracking. Only the
# affected language-standard variants are excluded so coverage is otherwise kept:
# - test-comparison-cpp20_cpp20, test-comparison_legacy-cpp20_cpp20
# - test-comparison_cpp20, test-comparison_legacy_cpp20
# miscompiles cross-type/<=> comparison (e.g. `-17 <= null`)
# - test-constructor1_cpp11
# std::initializer_list lifetime bug -> SIGSEGV
# - test-deserialization-cpp20_cpp20
# - test-deserialization_cpp20
# mangles the UTF-8 u8"" string literal in the char8_t (C++20) section
add_custom_target(ci_nvhpc
COMMAND ${CMAKE_COMMAND}
@@ -906,7 +899,7 @@ add_custom_target(ci_nvhpc
COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_nvhpc
# the pipes are escaped so the surrounding shell passes them to ctest verbatim
# instead of treating them as shell pipe operators
COMMAND cd ${PROJECT_BINARY_DIR}/build_nvhpc && ${CMAKE_CTEST_COMMAND} --parallel ${N} --exclude-regex "test-comparison-cpp20_cpp20\\|test-comparison_legacy-cpp20_cpp20\\|test-constructor1_cpp11\\|test-deserialization-cpp20_cpp20" --output-on-failure
COMMAND cd ${PROJECT_BINARY_DIR}/build_nvhpc && ${CMAKE_CTEST_COMMAND} --parallel ${N} --exclude-regex "test-comparison_cpp20\\|test-comparison_legacy_cpp20\\|test-constructor1_cpp11\\|test-deserialization_cpp20" --output-on-failure
COMMENT "Compile and test with NVIDIA HPC SDK (nvc++)"
)
+1 -1
View File
@@ -1 +1 @@
cppcheck==1.5.3
cppcheck==1.5.1
+39 -366
View File
@@ -109,55 +109,6 @@ function(_json_test_apply_test_properties test_target properties_target)
endif()
endfunction()
# for internal use by _json_test_add_test() and _json_test_add_unity_batch():
# registers the CTest test <test_name>_cpp<cxx_standard> (plus its Valgrind
# variant), which runs the executable target <test_target> with the arguments
# in ARGN, and applies the test properties of the test- and standard-specific
# interface targets
function(_json_test_register_test test_name test_target cxx_standard)
set(ctest_name ${test_name}_cpp${cxx_standard})
if (JSON_FastTests)
add_test(NAME ${ctest_name}
COMMAND ${test_target} ${DOCTEST_TEST_FILTER} ${ARGN}
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
)
else()
add_test(NAME ${ctest_name}
COMMAND ${test_target} ${DOCTEST_TEST_FILTER} ${ARGN} --no-skip
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
)
endif()
set_tests_properties(${ctest_name} PROPERTIES LABELS "all" FIXTURES_REQUIRED TEST_DATA)
# apply standard-specific test properties
if(TARGET _json_test_interface__cpp_${cxx_standard})
_json_test_apply_test_properties(${ctest_name} _json_test_interface__cpp_${cxx_standard})
endif()
# apply test-specific test properties
if(TARGET _json_test_interface_${test_name})
_json_test_apply_test_properties(${ctest_name} _json_test_interface_${test_name})
endif()
# apply test- and standard-specific test properties
if(TARGET _json_test_interface_${test_name}_cpp_${cxx_standard})
_json_test_apply_test_properties(${ctest_name}
_json_test_interface_${test_name}_cpp_${cxx_standard}
)
endif()
if(JSON_Valgrind)
add_test(NAME ${ctest_name}_valgrind
COMMAND ${memcheck_command} $<TARGET_FILE:${test_target}> ${DOCTEST_TEST_FILTER} ${ARGN}
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
)
set_tests_properties(${ctest_name}_valgrind PROPERTIES
LABELS "valgrind" FIXTURES_REQUIRED TEST_DATA
)
endif()
endfunction()
# for internal use by json_test_add_test_for()
function(_json_test_add_test test_name file main cxx_standard)
set(test_target ${test_name}_cpp${cxx_standard})
@@ -192,7 +143,45 @@ function(_json_test_add_test test_name file main cxx_standard)
)
endif()
_json_test_register_test(${test_name} ${test_target} ${cxx_standard})
if (JSON_FastTests)
add_test(NAME ${test_target}
COMMAND ${test_target} ${DOCTEST_TEST_FILTER}
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
)
else()
add_test(NAME ${test_target}
COMMAND ${test_target} ${DOCTEST_TEST_FILTER} --no-skip
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
)
endif()
set_tests_properties(${test_target} PROPERTIES LABELS "all" FIXTURES_REQUIRED TEST_DATA)
# apply standard-specific test properties
if(TARGET _json_test_interface__cpp_${cxx_standard})
_json_test_apply_test_properties(${test_target} _json_test_interface__cpp_${cxx_standard})
endif()
# apply test-specific test properties
if(TARGET _json_test_interface_${test_name})
_json_test_apply_test_properties(${test_target} _json_test_interface_${test_name})
endif()
# apply test- and standard-specific test properties
if(TARGET _json_test_interface_${test_name}_cpp_${cxx_standard})
_json_test_apply_test_properties(${test_target}
_json_test_interface_${test_name}_cpp_${cxx_standard}
)
endif()
if(JSON_Valgrind)
add_test(NAME ${test_target}_valgrind
COMMAND ${memcheck_command} $<TARGET_FILE:${test_target}> ${DOCTEST_TEST_FILTER}
WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
)
set_tests_properties(${test_target}_valgrind PROPERTIES
LABELS "valgrind" FIXTURES_REQUIRED TEST_DATA
)
endif()
endfunction()
#############################################################################
@@ -211,14 +200,6 @@ endfunction()
# Use NAME <name> to override the filename-derived test name.
# Use FORCE to create the test regardless of the file containing
# JSON_HAS_CPP_<version_number>.
#
# Tests that depend on the C++ standard (e.g., because they use the macros
# JSON_HAS_FILESYSTEM, JSON_HAS_RANGES, or JSON_HAS_THREE_WAY_COMPARISON)
# should not make the whole of a large unit-foo.cpp be rebuilt for every
# standard. Put them into a separate file unit-foo-cpp<NN>.cpp (see, e.g.,
# unit-items-cpp17.cpp) which wraps its content in #ifdef JSON_HAS_CPP_<NN>.
# Then, unit-foo.cpp itself contains no JSON_HAS_CPP_<NN> and is only built for
# C++11.
# Test targets are linked against <main>.
# CXX_STANDARDS defaults to "11".
#############################################################################
@@ -262,314 +243,6 @@ function(json_test_add_test_for file)
endforeach()
endfunction()
# for internal use by json_test_add_unity_tests(): sets <result> to whether the
# (absolute) <file> is built for <cxx_standard>; same rule as in
# json_test_add_test_for(): C++11 always, others only if the file contains
# JSON_HAS_CPP_<cxx_standard> or <force> is set
function(_json_test_unity_applies file cxx_standard force result)
set(${result} TRUE PARENT_SCOPE)
if(NOT ("${cxx_standard}" STREQUAL 11 OR force))
file(READ ${file} file_content)
string(FIND "${file_content}" JSON_HAS_CPP_${cxx_standard} has_cpp_found)
if(${has_cpp_found} EQUAL -1)
set(${result} FALSE PARENT_SCOPE)
endif()
endif()
endfunction()
# for internal use by json_test_add_unity_tests(): creates the executable
# test-unity-<batch_name>_cpp<cxx_standard> from the (absolute) source files
# in ARGN, which are #include-d by a generated source file, and registers one
# CTest test per source file that runs only the test cases of that file; if
# <private> is true, the generated file defines JSON_TESTS_PRIVATE first
function(_json_test_add_unity_batch batch_name cxx_standard main private)
set(batch_target test-unity-${batch_name}_cpp${cxx_standard})
set(batch_source ${PROJECT_BINARY_DIR}/tests/unity/${batch_target}.cpp)
set(batch_content "// generated by cmake/test.cmake; do not edit\n")
if(private)
string(APPEND batch_content "// at least one file of this batch needs access to private members of the library\n")
string(APPEND batch_content "#define JSON_TESTS_PRIVATE\n")
# the files define the macro again; mark this definition as used, as
# -Wunused-macros reports an unused definition when it is redefined
string(APPEND batch_content "#ifdef JSON_TESTS_PRIVATE\n#endif\n")
endif()
foreach(file ${ARGN})
string(APPEND batch_content "#include \"${file}\" // NOLINT(bugprone-suspicious-include)\n")
endforeach()
# only touch the generated file if it changed to keep incremental builds incremental
set(old_content "")
if(EXISTS ${batch_source})
file(READ ${batch_source} old_content)
endif()
if(NOT "${old_content}" STREQUAL "${batch_content}")
file(WRITE ${batch_source} "${batch_content}")
endif()
add_executable(${batch_target} ${batch_source})
target_link_libraries(${batch_target} PRIVATE ${main})
set_target_properties(${batch_target} PROPERTIES
CXX_STANDARD ${cxx_standard}
CXX_STANDARD_REQUIRED ON
)
if(TARGET _json_test_interface__cpp_${cxx_standard})
target_link_libraries(${batch_target} PRIVATE _json_test_interface__cpp_${cxx_standard})
endif()
# rebuild the batch when one of its files changes, and show the files in IDEs;
# files that are also built standalone (VARIANT_FILES) are left out, as
# HEADER_FILE_ONLY is a per-file property and would also affect those targets
set_source_files_properties(${batch_source} PROPERTIES OBJECT_DEPENDS "${ARGN}")
foreach(file ${ARGN})
if(NOT file IN_LIST _json_test_unity_variant_files)
set_source_files_properties(${file} PROPERTIES HEADER_FILE_ONLY ON)
target_sources(${batch_target} PRIVATE ${file})
endif()
endforeach()
foreach(file ${ARGN})
get_filename_component(file_basename ${file} NAME_WE)
string(REGEX REPLACE "unit-(.+)" "test-\\1" test_name ${file_basename})
# run only the test cases defined in this file (and in the shared
# make_test_data_available.hpp if the file uses it)
file(READ ${file} file_content)
set(source_filter "--source-file=*${file_basename}.cpp")
string(FIND "${file_content}" make_test_data_available.hpp uses_test_data)
if(NOT ${uses_test_data} EQUAL -1)
string(APPEND source_filter ",*make_test_data_available.hpp")
endif()
_json_test_register_test(${test_name} ${batch_target} ${cxx_standard} "${source_filter}")
endforeach()
endfunction()
#############################################################################
# json_test_add_unity_tests(
# FILES <files>...
# MAIN <main>
# [CXX_STANDARDS <version_number>...] [FORCE]
# [BATCH_SIZE <size>]
# [GROUPS <group>...]
# [VARIANT_FILES <files>...])
#
# Like calling json_test_add_test_for(<file> MAIN <main> ...) for each of the
# <files>, but compiles several files together to speed up the build: for each
# C++ standard, the files are split into batches of <size> files (default: 8)
# and each batch is built as a single executable
#
# test-unity-<pool><index>_cpp<version_number>
#
# whose generated source file #include-s the files of the batch (so they share
# the template instantiations of the library). The tests are still named
# test-foo_cpp<version_number>, one per file, but run the batch executable with
# a doctest filter that selects the test cases of that file only.
#
# Files are only batched with files that agree on the macros defined before
# the library is included: files that define at most JSON_TESTS_PRIVATE (or
# macros derived from global compile definitions) form the pools "plain" and
# "private". All other files are added with json_test_add_test_for() as usual,
# as are files with test-specific build settings (see
# json_test_set_test_options()) and the files listed in the explicit
# exclusion list below.
# Each <group> names a list variable json_test_unity_group_<group> of test file
# stems (file names without "unit-" and ".cpp"). The batchable files of a group
# are compiled together (regardless of BATCH_SIZE) as one executable
#
# test-unity-<group>_cpp<version_number>
#
# so that related tests, which instantiate the same templates, share one
# translation unit. A group may mix the pools "plain" and "private"; if any of
# its files needs JSON_TESTS_PRIVATE, the whole group is built with it. Files
# that cannot be batched stay standalone even if they are listed in a group.
# Files in no group are batched by BATCH_SIZE as described above.
# <files> in VARIANT_FILES are also built standalone with other settings, so
# they are not marked as header-only sources of the batch.
#############################################################################
function(json_test_add_unity_tests)
cmake_parse_arguments(args "FORCE" "MAIN;BATCH_SIZE" "FILES;CXX_STANDARDS;VARIANT_FILES;GROUPS" ${ARGN})
if("${args_MAIN}" STREQUAL "")
message(FATAL_ERROR "Required argument MAIN <main> missing.")
endif()
if("${args_BATCH_SIZE}" STREQUAL "")
set(args_BATCH_SIZE 8)
endif()
if("${args_CXX_STANDARDS}" STREQUAL "")
set(args_CXX_STANDARDS 11)
endif()
if(args_FORCE)
set(force FORCE)
else()
set(force "")
endif()
set(_json_test_unity_variant_files "")
foreach(file ${args_VARIANT_FILES})
get_filename_component(file ${file} ABSOLUTE)
list(APPEND _json_test_unity_variant_files ${file})
endforeach()
# files that must not be merged into a batch: unit-32bit.cpp is only built
# for 32bit targets, and unit-no-macro-leak.cpp checks that including the
# library defines no unprefixed macro, which any other file would disturb
set(standalone_files unit-32bit.cpp unit-no-macro-leak.cpp)
set(harmless_macros "^(DOCTEST_.*|SKIP_TESTS_FOR_.*|JSON_TEST_DEPRECATED_FUNCTIONS_DELETED|JSON_TEST_STRICT_NUL_HANDLING_ENABLED|JSON_TEST_STRINGIZE)$")
# classify the files
set(plain_files "")
set(private_files "")
set(standalone_abs_files "")
foreach(file ${args_FILES})
get_filename_component(file_name ${file} NAME)
get_filename_component(file_basename ${file} NAME_WE)
string(REGEX REPLACE "unit-(.+)" "test-\\1" test_name ${file_basename})
set(batchable TRUE)
if(file_name IN_LIST standalone_files)
set(batchable FALSE)
endif()
if(TARGET _json_test_interface_${test_name})
set(batchable FALSE)
endif()
foreach(cxx_standard ${args_CXX_STANDARDS})
if(TARGET _json_test_interface_${test_name}_cpp_${cxx_standard})
set(batchable FALSE)
endif()
endforeach()
# files that suppress GCC's -Wnoexcept around their include of the
# library: the suppression has no effect once another file of the
# batch included the library first
if(batchable)
file(READ ${file} file_content)
string(FIND "${file_content}" "SUPPRESS_WARNING(\"-Wnoexcept\")" suppresses_noexcept)
if(NOT ${suppresses_noexcept} EQUAL -1)
set(batchable FALSE)
endif()
endif()
set(pool plain)
if(batchable)
# collect the macros (un)defined before the library is included
file(READ ${file} file_content)
string(FIND "${file_content}" "#include <nlohmann/" include_position)
if(NOT ${include_position} EQUAL -1)
string(SUBSTRING "${file_content}" 0 ${include_position} file_content)
endif()
string(REGEX MATCHALL "(^|\n)[ \t]*#[ \t]*(define|undef)[ \t]+[A-Za-z_0-9]+" directives "${file_content}")
foreach(directive ${directives})
string(REGEX REPLACE "^.*[ \t]([A-Za-z_0-9]+)$" "\\1" macro "${directive}")
if(macro MATCHES "${harmless_macros}")
continue()
elseif("${macro}" STREQUAL JSON_TESTS_PRIVATE)
set(pool private)
else()
set(batchable FALSE)
endif()
endforeach()
endif()
get_filename_component(file_abs ${file} ABSOLUTE)
if(NOT batchable)
list(APPEND standalone_abs_files ${file_abs})
json_test_add_test_for(${file} MAIN ${args_MAIN} CXX_STANDARDS ${args_CXX_STANDARDS} ${force})
continue()
endif()
get_filename_component(file ${file} ABSOLUTE)
list(APPEND ${pool}_files ${file})
endforeach()
# resolve the explicit groups: group_<name>_files are the (absolute) files
# of the group, group_<name>_private tells whether one of them is private
set(grouped_files "")
foreach(group ${args_GROUPS})
if(NOT DEFINED json_test_unity_group_${group})
message(FATAL_ERROR "Unity test group '${group}' is not defined (json_test_unity_group_${group}).")
endif()
set(group_${group}_files "")
set(group_${group}_private FALSE)
foreach(stem ${json_test_unity_group_${group}})
# check against the source directory, because FILES may be filtered (JSON_TestShard)
get_filename_component(file ${CMAKE_CURRENT_SOURCE_DIR}/src/unit-${stem}.cpp ABSOLUTE)
if(NOT EXISTS ${file})
message(FATAL_ERROR "Unity test group '${group}' lists '${stem}', but ${file} does not exist.")
endif()
if(file IN_LIST grouped_files)
message(FATAL_ERROR "Unity test file unit-${stem}.cpp is listed in more than one group (second: '${group}').")
endif()
list(APPEND grouped_files ${file})
if(file IN_LIST standalone_abs_files)
message(STATUS "Unity test group '${group}': unit-${stem}.cpp cannot be batched and stays standalone")
elseif(file IN_LIST plain_files)
list(APPEND group_${group}_files ${file})
list(REMOVE_ITEM plain_files ${file})
elseif(file IN_LIST private_files)
list(APPEND group_${group}_files ${file})
list(REMOVE_ITEM private_files ${file})
set(group_${group}_private TRUE)
endif()
endforeach()
endforeach()
foreach(cxx_standard ${args_CXX_STANDARDS})
if(NOT compiler_supports_cpp_${cxx_standard})
continue()
endif()
# explicit groups: one batch per group
foreach(group ${args_GROUPS})
set(batch_files "")
foreach(file ${group_${group}_files})
_json_test_unity_applies(${file} ${cxx_standard} "${force}" applies)
if(applies)
list(APPEND batch_files ${file})
endif()
endforeach()
if(batch_files)
_json_test_add_unity_batch(${group} ${cxx_standard} ${args_MAIN} ${group_${group}_private} ${batch_files})
endif()
endforeach()
# remaining files: batches of BATCH_SIZE files per pool
foreach(pool plain private)
set(is_private FALSE)
if(pool STREQUAL private)
set(is_private TRUE)
endif()
set(batch_files "")
set(batch_count 0)
set(batch_index 0)
foreach(file ${${pool}_files})
_json_test_unity_applies(${file} ${cxx_standard} "${force}" applies)
if(NOT applies)
continue()
endif()
list(APPEND batch_files ${file})
math(EXPR batch_count "${batch_count} + 1")
if(batch_count EQUAL args_BATCH_SIZE)
_json_test_add_unity_batch(${pool}${batch_index} ${cxx_standard} ${args_MAIN} ${is_private} ${batch_files})
set(batch_files "")
set(batch_count 0)
math(EXPR batch_index "${batch_index} + 1")
endif()
endforeach()
if(batch_files)
_json_test_add_unity_batch(${pool}${batch_index} ${cxx_standard} ${args_MAIN} ${is_private} ${batch_files})
endif()
endforeach()
endforeach()
endfunction()
#############################################################################
# json_test_should_build_32bit_test(
# <build_32bit_var> <build_32bit_only_var> <input>)
@@ -132,10 +132,6 @@ 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
@@ -147,10 +143,6 @@ 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"
+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 type for
With the default values for `ArrayType` (`std::vector`) and `AllocatorType` (`std::allocator`), the default value for
`array_t` is:
```cpp
+1 -11
View File
@@ -68,14 +68,6 @@ 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.
@@ -244,9 +236,7 @@ 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. **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.
JSON value.
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.
+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 type for `boolean_t` is `#!cpp bool`.
With the default values for `BooleanType` (`#!cpp bool`), the default value for `boolean_t` is `#!cpp bool`.
### Storage
-2
View File
@@ -91,8 +91,6 @@ Binary values are serialized as an object containing two keys:
- [to_string](to_string.md) returns a string representation of a JSON value
- [operator<<](../operator_ltlt.md) serialize to stream
- [`basic_json_view::dump`](../basic_json_view/dump.md) the corresponding function of `basic_json_view`, serializing
directly from a flat index without building a `basic_json` value
- [Serialization](../../features/serialization.md) - the serialization article
## Version history
+1 -2
View File
@@ -93,8 +93,7 @@ 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 (a duplicate key resolves
to the first member, whereas `parse()` keeps the last)
- [basic_json_view::find](../basic_json_view/find.md) - the same lookup on a zero-copy view
## Version history
+1 -2
View File
@@ -51,8 +51,7 @@ 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 (document order, not
sorted; duplicate keys are visited)
- [basic_json_view::front](../basic_json_view/front.md) - the same access on a zero-copy view
## Version history
+1 -1
View File
@@ -85,7 +85,7 @@ The class satisfies the following concept requirements:
- [EqualityComparable](https://en.cppreference.com/w/cpp/named_req/EqualityComparable): JSON values can be compared with
`==`, see [`operator==`](operator_eq.md).
- [LessThanComparable](https://en.cppreference.com/w/cpp/named_req/LessThanComparable): JSON values can be compared with
`<`, see [`operator<`](operator_lt.md).
`<`, see [`operator<`](operator_le.md).
- [Swappable](https://en.cppreference.com/w/cpp/named_req/Swappable): Any JSON lvalue or rvalue of can be swapped with
any lvalue or rvalue of other compatible types, using unqualified function `swap`.
- [NullablePointer](https://en.cppreference.com/w/cpp/named_req/NullablePointer): JSON values can be compared against
@@ -6,9 +6,6 @@ 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
+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; document order, not sorted; duplicate keys are visited)
not `#!cpp const auto&`: items are produced on the fly)
## Version history
@@ -11,7 +11,7 @@ added members with their new values, and removed members with the value `#!json
member by member; any other value that differs, including an array, is replaced as a whole.
For two JSON values `source` and `target`, where `target` contains no object member whose value is `#!json null`, the
following code always yields `#!cpp true` (for [`ordered_json`](../ordered_json.md), see the notes below):
following code always yields `#!cpp true`:
```cpp
basic_json patched = source;
patched.merge_patch(merge_diff(source, target));
@@ -35,7 +35,7 @@ type to use.
### Default type
With the default values for `NumberFloatType` (`double`), the default type for `number_float_t` is `#!cpp double`.
With the default values for `NumberFloatType` (`double`), the default value for `number_float_t` is `#!cpp double`.
### Default behavior
@@ -52,11 +52,9 @@ With the default values for `NumberFloatType` (`double`), the default type 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 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`.
This implementation does exactly follow this approach, as it uses double precision floating-point numbers. Note values
smaller than `-1.79769313486232e+308` and values greater than `1.79769313486232e+308` will be stored as NaN internally
and be serialized to `null`.
During deserialization (from JSON text or any of the binary formats), a finite number that does not fit into
`number_float_t` is rejected with [`out_of_range.406`](../../home/exceptions.md#jsonexceptionout_of_range406), for
@@ -31,7 +31,7 @@ to use.
### Default type
With the default values for `NumberIntegerType` (`std::int64_t`), the default type for `number_integer_t` is
With the default values for `NumberIntegerType` (`std::int64_t`), the default value for `number_integer_t` is
`#!cpp std::int64_t`.
### Default behavior
@@ -25,15 +25,14 @@ 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. 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
[`number_integer_t`](number_integer_t.md) value. 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 type for `number_unsigned_t` is
With the default values for `NumberUnsignedType` (`std::uint64_t`), the default value for `number_unsigned_t` is
`#!cpp std::uint64_t`.
### Default behavior
@@ -90,4 +89,3 @@ 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.
+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 type for `object_t` is:
(`std::allocator`), the default value for `object_t` is:
```cpp
// until C++14
@@ -275,9 +275,8 @@ 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 (a duplicate
key resolves to the first member, whereas `parse()` keeps the last; a missing key gives a discarded view instead of
undefined behavior)
- [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)
## Version history
@@ -20,8 +20,7 @@ bool operator==(ScalarType rhs) const noexcept(/* see below */); // (2)
1. Compares two JSON values for equality according to the following rules:
- Two JSON values are equal if (1) neither value is discarded, and (2) they are of the same type and their stored
values are the same according to their respective `operator==`.
- Integer and floating-point numbers are compared by their exact values, without converting the integer to
floating-point. For instance, `9007199254740993` and `9007199254740992.0` are not equal.
- Integer and floating-point numbers are automatically converted before comparison.
2. Compares a JSON value and a scalar or a scalar and a JSON value for equality by converting the
scalar to a JSON value and comparing both JSON values according to 1.
@@ -170,8 +169,6 @@ Linear.
- [operator!=](operator_ne.md) compare for inequality
- [operator<=>](operator_spaceship.md) comparison: 3-way (C++20)
- [basic_json_view::operator==](../basic_json_view/operator_eq.md) - the same comparison on a zero-copy view, without
building a `basic_json` value for it
## Version history
@@ -15,8 +15,7 @@ bool operator<(ScalarType lhs, const const_reference rhs) noexcept(/* see below
following rules:
- If either operand is discarded, the comparison yields `#!cpp false`.
- If both operands have the same type, the values are compared using their respective `operator<`.
- Integer and floating-point numbers are compared by their exact values, without converting the integer to
floating-point. For instance, `9007199254740992.0` is less than `9007199254740993`.
- Integer and floating-point numbers are automatically converted before comparison.
- In case `lhs` and `rhs` have different types, the values are ignored and the order of the types
is considered, which is:
1. null
@@ -95,8 +95,6 @@ Linear.
- [operator==](operator_eq.md) comparison: equal
- [operator<=>](operator_spaceship.md) comparison: 3-way (C++20)
- [basic_json_view::operator!=](../basic_json_view/operator_ne.md) - the same comparison on a zero-copy view, without
building a `basic_json` value for it
## Version history
@@ -12,8 +12,10 @@ std::partial_ordering operator<=>(const ScalarType rhs) const noexcept(/* see be
- Two JSON values compare with a result of `std::partial_ordering::unordered` if either value is discarded.
- If both JSON values are of the same type, the result is produced by 3-way comparing their stored values using
their respective `operator<=>`.
- Integer and floating-point numbers are 3-way compared by their exact values, without converting the integer to
floating-point. For instance, `9007199254740993` compares greater than `9007199254740992.0`.
- Integer and floating-point numbers are converted to their common type and then 3-way compared using their
respective `operator<=>`.
For instance, comparing an integer and a floating-point value will 3-way compare the first value converted to
floating-point with the second value.
- Otherwise, yields a result by comparing the type (see [`value_t`](value_t.md)).
2. 3-way compares a JSON value and a scalar or a scalar and a JSON value by converting the scalar to a JSON value and
-19
View File
@@ -112,16 +112,6 @@ 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"
@@ -257,10 +247,6 @@ 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
@@ -275,11 +261,6 @@ 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"
+1 -1
View File
@@ -45,7 +45,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
pointer inside the patch cannot be resolved, e.g., `-` in a "remove" operation or `1a` for an array; example:
`"unresolved reference token '-'"`.
- Throws [`out_of_range.405`](../../home/exceptions.md#jsonexceptionout_of_range405) if JSON pointer has no parent
("remove", "move")
("add", "remove", "move")
- Throws [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) if an "add" operation's target
location has a parent that is neither an object nor an array.
- Throws [`out_of_range.413`](../../home/exceptions.md#jsonexceptionout_of_range413) if a "remove" operation's target
@@ -41,7 +41,7 @@ No guarantees, value may be corrupted by an unsuccessful patch operation.
pointer inside the patch cannot be resolved, e.g., `-` in a "remove" operation or `1a` for an array; example:
`"unresolved reference token '-'"`.
- Throws [`out_of_range.405`](../../home/exceptions.md#jsonexceptionout_of_range405) if JSON pointer has no parent
("remove", "move")
("add", "remove", "move")
- Throws [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) if an "add" operation's target
location has a parent that is neither an object nor an array.
- Throws [`out_of_range.413`](../../home/exceptions.md#jsonexceptionout_of_range413) if a "remove" operation's target
@@ -116,10 +116,6 @@ 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
@@ -141,10 +137,6 @@ use the same file with stdio functions, but it must not wait for another thread
- [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
@@ -156,10 +148,6 @@ use the same file with stdio functions, but it must not wait for another thread
- 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"
+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 type for `string_t` is `#!cpp std::string`.
With the default values for `StringType` (`std::string`), the default value for `string_t` is `#!cpp std::string`.
### Encoding
+1 -3
View File
@@ -123,6 +123,4 @@ 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.
- Writes unsigned integers wider than 64 bits as high-precision numbers since version 3.13.0; previously, they were
silently truncated to 64 bits.
array or object was silently skipped, producing invalid BJData.
+2 -3
View File
@@ -37,9 +37,8 @@ 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 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 [out_of_range.407](../../home/exceptions.md#jsonexceptionout_of_range407) if `j` contains an unsigned integer
above 9223372036854775807, 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
@@ -47,10 +47,6 @@ 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,
@@ -123,5 +119,3 @@ 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.
@@ -46,9 +46,6 @@ 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)
@@ -93,5 +90,3 @@ 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.
@@ -46,9 +46,6 @@ 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"`
@@ -115,5 +112,3 @@ 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.
@@ -12,11 +12,6 @@ Checks whether the input is valid JSON, accepting and rejecting exactly what
function never throws an exception for invalid input, and the returned `#!cpp bool` is the only result -- no document
is returned.
The result is the same as that of `BasicJsonType::accept()` by design; the difference is how the check is made. This
function runs the document's index builder (and discards the index), while `BasicJsonType::accept()` runs the SAX
parser with a handler that ignores every event. Use this one if you go on to parse the same input with
[`parse()`](parse.md) anyway, so that both use the same code; either is fine for a plain yes/no answer.
## Template parameters
`InputType`
@@ -16,8 +16,8 @@ basic_json_document(const basic_json_document&) = delete;
2. Move constructor. Takes over `other`'s index and, if owned, its text; `other` is left as an empty document. Views
taken from `other` before the move remain valid, because the index is heap-allocated independently of the
`basic_json_document` object.
3. `basic_json_document` is move-only. Copying is disabled because of its cost: a copy would duplicate the whole
index, the decoded-string buffer, and the owned text, while a move is enough in every use we know of.
3. `basic_json_document` is move-only. Copying is disabled because it would either duplicate a potentially large index
and text, or leave two documents claiming to borrow the same buffer.
## Parameters
@@ -30,7 +30,7 @@ No-throw guarantee: the default and move constructors never throw exceptions.
## Complexity
Constant.
Constant, for the default and move constructors.
## Examples
@@ -1,129 +0,0 @@
# <small>nlohmann::basic_json_document::</small>erase
```cpp
// (1)
std::size_t erase(view_type object, string_view_t key);
// (2)
template<typename I>
void erase(view_type array, I idx);
// (3)
std::size_t erase(const json_pointer& ptr);
```
Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
has `erase`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
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). `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
`I`
: an integral type other than `#!cpp bool`, deduced (overloads taking a `#!cpp bool` or a non-integral type for
`idx` do not participate in overload resolution).
## Parameters
`object` (in)
: the object to remove a member of
`array` (in)
: the array to remove an element of
`key` (in)
: the key of the member(s) to remove
`idx` (in)
: the index of the element to remove; a negative value throws (see [Exceptions](#exceptions))
`ptr` (in)
: a JSON pointer to the value to remove, relative to `root()`
## Return value
1. the number of removed members (`#!cpp 0` if `object` had none with this `key`)
2. (nothing)
3. the number of removed values (`#!cpp 0` or more for an object member, always `#!cpp 1` for an array element)
## Exceptions
1. Throws [`type_error.307`](../../home/exceptions.md#jsonexceptiontype_error307) if `object` is not an object -- the
same message [`BasicJsonType::erase`](../basic_json/erase.md) throws for the same type.
2. Throws `type_error.307` if `array` is not an array. Throws
[`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if `idx` is negative, or if
`#!cpp idx >= array.size()`.
3. Throws [`out_of_range.405`](../../home/exceptions.md#jsonexceptionout_of_range405) ("JSON pointer has no parent")
if `ptr` is empty. Throws what [`at`](../basic_json_view/at.md) throws (overload 3) for resolving `ptr`'s parent.
For the last reference token itself: if the parent is an array, throws what 2. throws for an index that is out of
range, or, for a token that is not a valid array index,
[`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) (a leading `#!cpp '0'`),
[`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) (not a number),
[`out_of_range.410`](../../home/exceptions.md#jsonexceptionout_of_range410) (too large for `size_type`), or
[`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.
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
1. Linear in the number of members of `object`.
2. Linear in the number of elements of `array` at or after `idx` (they move one slot over).
3. 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 [`at`](../basic_json_view/at.md)), plus the complexity of 1. or 2. for
the last token.
## Notes
!!! info "Duplicate keys"
Overload 1. removes *every* member with `key`, not just the first -- unlike [`set`](set.md), which assigns the
first occurrence and drops the rest. This is why it returns a count rather than a single view: there may be
more than one member removed, or none.
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. 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
??? example
The example below drops a deprecated field and a decommissioned entry from a configuration document -- using all
three overloads -- and shows what stays intact that would not with a plain `json`/`ordered_json` value: the order
of the fields around the ones removed, and the exact spelling of a number that was never touched.
```cpp
--8<-- "examples/basic_json_document__erase.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__erase.output"
```
## See also
- [insert](insert.md) - insert an element into an array
- [set](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers to
- [push_back](push_back.md) - append to an array
- [root](root.md) - the view of the root value, the starting point of overload 3
- [`BasicJsonType::erase`](../basic_json/erase.md) - the corresponding function of `basic_json`
- [Edits](index.md#edits) - what an edit guarantees, for every overload
## Version history
- Added in version 3.13.0.
@@ -3,7 +3,7 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
template<typename BasicJsonType, bool Editable = false>
template<typename BasicJsonType>
class basic_json_document;
```
@@ -11,19 +11,13 @@ A parsed JSON text, held as a flat index of its values
([16 bytes per value](../../home/architecture.md#node-index-of-json-views)) instead of a tree of `BasicJsonType` values.
Strings and numbers stay in the source text; only strings that contain escapes are decoded, into one buffer owned by
the document. [`basic_json_view`](../basic_json_view/index.md) is a read-only handle to one value of a
`basic_json_document`; [`materialize()`](../basic_json_view/materialize.md) turns a subtree into the
`basic_json_document`; [`materialize()`](../basic_json_view/materialize.md) turns a subtree back into the
`BasicJsonType` value that [`BasicJsonType::parse()`](../basic_json/parse.md) would have produced for it.
A document may **borrow** the text it was parsed from (the caller's buffer must then outlive the document) or **own**
it (a copy, or an rvalue `#!cpp std::string` that was moved in); see [`owns_source`](owns_source.md). `basic_json_document`
is move-only: a copy would duplicate the whole index, the decoded-string buffer, and the owned text, and a move is
enough in every use we know of. The index, the decoded strings, and the owned text live in one heap block that the
document holds through a `#!cpp std::unique_ptr`; this is also why views survive a move of the document.
With `#!cpp Editable == true`, the document also offers [`set`](set.md), [`push_back`](push_back.md),
[`insert`](insert.md), and [`erase`](erase.md) to change values in place, see [Edits](#edits) below. The source text
itself is never written; a read-only document (`#!cpp Editable == false`, the default) does not carry any of the
bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp static_assert`).
is move-only: copying a document would either duplicate a potentially large index and text, or leave two documents
claiming to borrow the same buffer, so it is disabled.
## Template parameters
@@ -32,38 +26,23 @@ bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp
[`ordered_json`](../ordered_json.md). Only 64-bit `number_integer_t`/`number_unsigned_t` types are supported; this
is checked with a `static_assert`.
`Editable`
: whether the document supports [`set`](set.md), [`push_back`](push_back.md), [`insert`](insert.md), and
[`erase`](erase.md) (optional, `#!cpp false` by default). See [Edits](#edits) below.
## Specializations
- [**json_document**](../json_document.md) - read-only documents of the default specialization [`json`](../json.md)
- [**ordered_json_document**](../ordered_json_document.md) - read-only documents of
[`ordered_json`](../ordered_json.md)
- [**json_editable_document**](../json_editable_document.md) - editable documents of [`json`](../json.md)
- [**ordered_json_editable_document**](../ordered_json_editable_document.md) - editable documents of
[`ordered_json`](../ordered_json.md)
- [**json_document**](../json_document.md) - documents of the default specialization [`json`](../json.md)
- [**ordered_json_document**](../ordered_json_document.md) - documents of [`ordered_json`](../ordered_json.md)
## Member types
- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType, Editable>`)
- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType>`)
- **value_t** - the JSON type enumeration, see [`basic_json::value_t`](../basic_json/value_t.md)
- **image_check** - how [`load()`](load.md) validates an image (`full`, `bounds`, `none`), see [`image_check`](load.md#image_check)
## Member functions
- [(constructor)](basic_json_document.md)
### Parsing
- [**parse**](parse.md) (_static_) - deserialize from a compatible input, borrowing or owning it as appropriate
- [**parse_copy**](parse_copy.md) (_static_) - deserialize a copy of a compatible input
- [**accept**](accept.md) (_static_) - check whether the input is valid JSON
- [**read**](read.md) - (re-)parse into this document, reusing its memory
### Access
- [**root**](root.md) - the view of the root value
- [**is_discarded**](is_discarded.md) - return whether the last parse failed
- [**source**](source.md) - the parsed text
@@ -72,49 +51,6 @@ bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp
- [**memory_usage**](memory_usage.md) - the number of bytes held by the document
- [**shrink_to_fit**](shrink_to_fit.md) - release unused index capacity
### Images
- [**save**](save.md) - the document as an image that `load()` reads without parsing
- [**load**](load.md) (_static_) - read an image written by `save()`
### Edits
- [**set**](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers
to (`#!cpp Editable` documents only)
- [**push_back**](push_back.md) - append to an array (`#!cpp Editable` documents only)
- [**insert**](insert.md) - insert an element into an array before a given position (`#!cpp Editable` documents only)
- [**erase**](erase.md) - remove an object member, an array element, or the value a JSON pointer refers to
(`#!cpp Editable` documents only)
## Edits
An editable document (`#!cpp Editable == true`) can be changed after parsing, with [`set`](set.md),
[`push_back`](push_back.md), [`insert`](insert.md), and [`erase`](erase.md);
[`json_editable_document`](../json_editable_document.md) and
[`ordered_json_editable_document`](../ordered_json_editable_document.md) are the corresponding specializations. A few
points apply to every edit:
- **The source text is never written**, and the parsed index never moves: every value keeps the node it was parsed
into, so [views](../basic_json_view/index.md) taken before an edit stay valid, including
[`root()`](root.md). New values (and the element sequences of an edited array/object) go to storage owned by the
document, allocated on demand.
- **A view keeps referring to the same value.** After [`set`](set.md) replaces the value a view refers to, that view
sees the new value; a view of a value that a later edit replaces or drops keeps showing what it last held. An edit
of an array or object, however, **invalidates the iterators taken over it** (its members may now live in a
different sequence), and a string obtained with [`get_string()`](../basic_json_view/get_string.md) stays valid even
as further edits happen (earlier buffers of edited text are kept alive, not overwritten).
- **Values are accepted three ways:** a [`basic_json_view`](../basic_json_view/index.md) of *any* document
(read-only or editable; it is copied, nothing is shared with the source document), a `BasicJsonType` value, or
anything `BasicJsonType` can be constructed from (numbers, strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
- [`dump()`](../basic_json_view/dump.md) writes an edited document with members in document order, new members at
the end, and, with [`number_format::source`](../basic_json_view/number_format.md), keeps the spelling of every
number that was not itself edited -- see [Editing a document](../../features/json_view.md#editing-a-document) for
why this matters.
- [`read()`](read.md) discards all edits, [`shrink_to_fit()`](shrink_to_fit.md) does not move the node index once
there are edits, and [`memory_usage()`](memory_usage.md) includes the memory edits use.
[`source_offset()`](../basic_json_view/source_offset.md) of a value introduced by an edit is
`#!cpp static_cast<std::size_t>(-1)`, the same value it reports for a decoded string.
## Version history
- Added in version 3.13.0.
@@ -1,114 +0,0 @@
# <small>nlohmann::basic_json_document::</small>insert
```cpp
template<typename I, typename V>
view_type insert(view_type array, I idx, V&& value);
```
Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
has `insert`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
Inserts `value` into `array` as a new element before position `idx`, which must not be past the end
(`#!cpp idx <= array.size()`; `#!cpp idx == array.size()` appends, like [`push_back`](push_back.md)). Unlike
[`push_back`](push_back.md), a [null](../basic_json_view/is_null.md) `array` does *not* first become an empty array:
`array` must already be an array.
`value` is accepted three ways: a [`basic_json_view`](../basic_json_view/index.md) of *any* document -- read-only or
editable, and it does not have to be `array`'s own document -- which is copied so that nothing is shared with the
source document afterward; a `BasicJsonType` value; or anything `BasicJsonType` can be constructed from (numbers,
strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
## Template parameters
`I`
: an integral type other than `#!cpp bool`, deduced (overloads taking a `#!cpp bool` or a non-integral type for
`idx` do not participate in overload resolution).
`V`
: the type of `value`, deduced; see above for what is accepted.
## Parameters
`array` (in)
: the array to insert into
`idx` (in)
: the position to insert `value` before; a negative value throws (see [Exceptions](#exceptions))
`value` (in)
: the value to insert
## Return value
a view of the new element, now holding `value`
## Exception safety
Basic exception safety: `value` is fully encoded -- including the checks below -- into storage owned by the document
before anything already reachable from [`root()`](root.md) is touched, so a failure while encoding `value` (an
invalid argument, or `#!cpp std::bad_alloc`) leaves the document completely unchanged, other than memory allocated
for the encoding that is not reclaimed. A failure of a later allocation -- while `array` switches from its parsed
layout to a growable block, or while that block grows, see [Notes](#notes) -- can still leave `array` already
switched to that layout even though `value` itself was not inserted.
## Exceptions
Throws [`type_error.309`](../../home/exceptions.md#jsonexceptiontype_error309) if `array` is not an array -- the same
message [`BasicJsonType::insert`](../basic_json/insert.md) throws for the same type; a null `array` throws this too
(see above). Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if `idx` is negative,
or if `#!cpp idx > array.size()`. Throws
[`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view does not belong to this
document") if `array` is a [discarded](../basic_json_view/is_discarded.md) view or a view of a *different* document.
Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if `value` is a
[discarded](../basic_json_view/is_discarded.md) view or a [discarded](../basic_json/is_discarded.md) `BasicJsonType`
value, and [`type_error.319`](../../home/exceptions.md#jsonexceptiontype_error319) if `value` is (or contains) a
binary value -- `BasicJsonType` can hold one, but a `json_document` cannot. Throws
[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) if `value` is (or contains) a string that is
not valid UTF-8, with the same message [`BasicJsonType::dump()`](../basic_json/dump.md) gives for that string.
## Complexity
Linear in the number of elements of `array` at or after `idx` (they move one slot over), plus time linear in the
size of `value` to encode it into the document's storage (constant for a scalar, linear in the number of nested
values for an array or object): like [`push_back`](push_back.md), the elements of `array` move to a growable block
of links the first time it is inserted into (or [`set`](set.md)/[`push_back`](push_back.md) on), and that block
grows in amortized constant time; inserting before the end within that block still shifts every later element.
## Notes
Like [`set`](set.md) on a member or an element, `insert` never moves an existing *element's value* -- only where
`array`'s *links* to its elements live -- so a view of an existing element of `array` stays valid across an
`insert`, and keeps referring to the same element even though its index shifts. Any iterator already taken over
`array` is invalidated, since it was walking the old layout. See [Edits](index.md#edits) for what stays valid across
an edit in general.
## Examples
??? example
The example below inserts a step into the middle of a deployment plan, without touching the steps that come
after it, and shows that a view taken before the insert keeps referring to the same element even though its
index shifts -- something a plain `json`/`ordered_json` array, or its `std::vector`-based storage, has no
equivalent for.
```cpp
--8<-- "examples/basic_json_document__insert.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__insert.output"
```
## See also
- [push_back](push_back.md) - append to an array
- [erase](erase.md) - remove an object member, an array element, or the value a JSON pointer refers to
- [set](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers to
- [`BasicJsonType::insert`](../basic_json/insert.md) - the corresponding function of `basic_json`
- [Edits](index.md#edits) - what an edit guarantees, for every overload
## Version history
- Added in version 3.13.0.
@@ -1,179 +0,0 @@
# <small>nlohmann::basic_json_document::</small>load
```cpp
// (1)
static basic_json_document load(const std::uint8_t* image, std::size_t size,
const image_check check = image_check::full);
// (2)
static basic_json_document load(const std::vector<std::uint8_t>& image,
const image_check check = image_check::full);
// (3)
static basic_json_document load(std::vector<std::uint8_t>&& image,
const image_check check = image_check::full);
```
1. Reads an image [`save()`](save.md) wrote, from a pointer and a byte count. The image is **borrowed**: `image`
must stay alive and unchanged for as long as the returned document, and any view taken from it, is used.
2. Reads an image from a `#!cpp std::vector`. Also **borrowed** -- equivalent to overload 1 called with
`#!cpp image.data()` and `#!cpp image.size()`.
3. Reads an image, keeping the vector instead of copying it: `image` is moved into the document (no copy), which
then owns it for as long as it needs the text and the decoded strings. [`owns_source()`](owns_source.md) is
`#!cpp true` afterward.
In every overload, the node index is copied into storage the document itself owns -- so that it is properly aligned,
and, for an [editable](index.md#edits) document, can be edited -- while the text and the decoded strings stay in
`image`. The hash indexes [large objects](../../features/json_view.md) use for lookup are rebuilt, exactly as after
parsing.
## Parameters
`image` (in)
: the image [`save()`](save.md) wrote (overloads 1 and 2), or one to take ownership of (overload 3)
`size` (in)
: the number of bytes at `image` (overload 1)
`check` (in)
: how thoroughly to validate `image` before trusting it; see [`image_check`](#image_check) below (optional,
`#!cpp image_check::full` by default)
## Return value
The document read from the image.
## Exception safety
Overloads 1 and 2 give the strong guarantee: `image` is only read, never written, so a thrown exception leaves the
caller's buffer untouched.
Overload 3 moves `image` into the document *before* validating it, so that a good image is kept without a copy. If
loading then fails, the partially built document -- and the vector now inside it -- is discarded along with the
exception, and `image` itself is left **empty**, not restored to what was passed in. Move a copy in instead, or
validate with overload 2 first, if the original vector must survive a failed load.
## Exceptions
On a big-endian target, throws [`type_error.320`](../../home/exceptions.md#jsonexceptiontype_error320) -- the same
exception [`save()`](save.md#exceptions) throws there, since the image format is little-endian only.
Otherwise throws [`parse_error.116`](../../home/exceptions.md#jsonexceptionparse_error116) if `image` is not one
`save()` could have written, or fails the requested `check`:
| message | when |
|------------------------|------------------------------------------------------------------------------------------------------|
| `too short` | `image` is `#!cpp nullptr`, or `size` is smaller than the 64-byte header |
| `unknown format` | the header's magic bytes or version do not match, or a reserved header field is not zero |
| `sizes out of range` | the node count, text size, or decoded-string size the header describes does not fit `size`, or the `#!cpp '\0'` after the text or after the decoded strings is missing |
| `the check failed` | `check` is not `#!cpp image_check::none`, and the image fails it -- see [`image_check`](#image_check) |
!!! failure "Example messages"
```
[json.exception.parse_error.116] parse error: invalid json_document image: too short
```
```
[json.exception.parse_error.116] parse error: invalid json_document image: unknown format
```
```
[json.exception.parse_error.116] parse error: invalid json_document image: sizes out of range
```
```
[json.exception.parse_error.116] parse error: invalid json_document image: the check failed
```
## Complexity
Linear in the number of nodes, which are always copied into the document. `#!cpp image_check::none` does not read
the text or the decoded strings. `#!cpp image_check::bounds` reads one byte of the text for each float token (its sign,
to check the recorded digits against the token's length), and nothing else of the text or the decoded strings.
With `#!cpp image_check::full`, linear in the size of the image (the nodes, the text, and the decoded strings), plus
sorting the ranges of the strings and of the float tokens (at most one per node): the contents of each distinct range
are checked once, however many nodes refer to it.
## Notes
### `image_check` { #image_check }
```cpp
using image_check = detail::view::image_check;
enum class image_check
{
full,
bounds,
none
};
```
How thoroughly `load()` validates `image` before trusting it.
`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.
`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
[`parse()`](parse.md) borrowed its input for. Overload 3 avoids this by keeping the vector itself; see
[`owns_source`](owns_source.md).
!!! warning "Experimental"
The image format is versioned but not yet stable, and may change in an incompatible way before it is declared
stable; `load()` already rejects an image written by a different format version with `parse_error.116`
("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.
## Examples
??? example "Caching a document, ownership, and a rejected image"
The example below saves a parsed document as an image, checks that `load()` reproduces the original
[`dump()`](../basic_json_view/dump.md) without parsing, and shows the difference between
`load(std::move(image))` (owned) and `load(image)` (borrowed). It then damages one byte of the image and shows
`image_check::full` rejecting it with `parse_error.116`, while `image_check::bounds` -- meant for a cache the
process already trusts -- still reads it without going out of bounds.
```cpp
--8<-- "examples/basic_json_document__load.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__load.output"
```
## See also
- [save](save.md) - write the document as an image
- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
- [parse](parse.md) - deserialize from JSON text instead of an image
- [Images](../../features/json_view.md#images) - why and when to use images
## Version history
- Added in version 3.13.0.
@@ -4,7 +4,7 @@
bool owns_source() const noexcept;
```
Returns whether the document holds its own copy of the parsed text or is borrowing the caller's buffer.
Returns whether the document holds its own copy of the parsed text, as opposed to borrowing the caller's buffer.
## Return value
@@ -21,15 +21,13 @@ static basic_json_document parse(IteratorType first, IteratorType last,
Both overloads accept the same JSON text as [`BasicJsonType::parse()`](../basic_json/parse.md), with the same
`ignore_comments`/`ignore_trailing_commas` options, but build a [`basic_json_document`](index.md) (a flat index into
the input) instead of a tree of `BasicJsonType` values. They take the same inputs as `BasicJsonType::parse()`. Byte
inputs that stay alive can be borrowed; all others (streams, `#!cpp FILE*`, wide characters, non-contiguous
iterators) are read into a copy that the document owns -- see the Notes. Use [`parse_copy()`](parse_copy.md) to get an
owned copy of a borrowable input as well.
the input) instead of a tree of `BasicJsonType` values. The input must be byte-oriented (see the template parameters
below): not every input type of `BasicJsonType::parse()` is supported.
## Template parameters
`InputType`
: A compatible input, for instance:
: A byte-oriented input, one of:
- a `#!cpp std::string`, `#!cpp std::string_view`, or a C-style array of single-byte characters
- a pointer to a null-terminated string of single-byte characters (`#!cpp char`, `#!cpp signed char`,
@@ -37,10 +35,12 @@ owned copy of a borrowable input as well.
- a container for which `#!cpp obj.data()` and `#!cpp obj.size()` give contiguous single-byte access, e.g.
`#!cpp std::vector<char>` or `#!cpp std::vector<std::uint8_t>`
- an `#!cpp std::istream` object
- a `#!cpp FILE*` pointer
- wide characters (`#!cpp wchar_t`, `#!cpp char16_t`, `#!cpp char32_t`), which are converted to UTF-8: a wide
string object (`#!cpp std::wstring`, `#!cpp std::u16string`, `#!cpp std::u32string`), an array (e.g. a wide
string literal), or a pointer to a null-terminated wide string
- a wide string object (`#!cpp std::wstring`, `#!cpp std::u16string`, `#!cpp std::u32string`), which is converted
to UTF-8
Other inputs are not supported: a `#!cpp FILE*`, and pointers to or arrays of wide characters (`#!cpp wchar_t`,
`#!cpp char16_t`, `#!cpp char32_t`) are rejected at compile time by a `#!cpp static_assert`. (Use
[`BasicJsonType::parse()`](../basic_json/parse.md) for these.)
`IteratorType`
: an input iterator type, for instance a pair of pointers such as `ptr` and `ptr + len`, or a pair of
@@ -78,9 +78,7 @@ discarded; see [`is_discarded`](is_discarded.md).
Throws the same exception [`BasicJsonType::parse()`](../basic_json/parse.md) throws for the same input and options --
the same exception id, message, and position -- because on a failing input the library's own parser is run on the
same bytes to produce the diagnostic. This replay runs only for a failing input, and costs about a lexing pass up to
the error (its SAX handler builds no values); with `allow_exceptions` set to `#!cpp false`, it is skipped and a
discarded document is returned instead. Additionally throws
same bytes to produce the diagnostic. Additionally throws
[`out_of_range.416`](../../home/exceptions.md#jsonexceptionout_of_range416) if the input is 4294967280 bytes (4 GiB
minus 16 bytes) or larger, a size [`BasicJsonType::parse()`](../basic_json/parse.md) does not reject.
@@ -97,7 +95,7 @@ Linear in the length of the input.
| lvalue byte container (`std::string`, `std::vector<char>`, ...), `std::string_view`, C string, character array | **borrowed** -- `input` must outlive the document |
| non-const rvalue `#!cpp std::string` | **owned**, moved in without a copy |
| other rvalue byte container (including a `#!cpp const` rvalue `#!cpp std::string`) | **owned**, copied |
| stream, `#!cpp FILE*`, wide characters, or anything else read through the general input adapter | **owned**, read into a buffer (a stream is read to its end) |
| stream, wide string, or anything else read through the general input adapter | **owned**, read into a buffer (a stream is read to its end) |
For overload (2), a pair of pointers to single-byte integers (e.g. `#!cpp const char*`, `#!cpp std::uint8_t*`) is
borrowed. From C++20 on, so is any other contiguous iterator over single bytes, such as
@@ -149,7 +147,6 @@ buffer of a given length, pass a pair of pointers: `#!cpp parse(ptr, ptr + len)`
- [accept](accept.md) - check whether the input is valid JSON
- [read](read.md) - (re-)parse into this document, reusing its memory
- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
- [load](load.md) - read a document from an image instead of parsing JSON text
- [`BasicJsonType::parse`](../basic_json/parse.md) - the corresponding function of `basic_json`
## Version history
@@ -1,102 +0,0 @@
# <small>nlohmann::basic_json_document::</small>push_back
```cpp
template<typename V>
view_type push_back(view_type array, V&& value);
```
Appends `value` as a new last element of `array`. A [null](../basic_json_view/is_null.md) `array` first becomes an
empty array, the same way [`set`](set.md) turns a null `object` into an empty object.
`value` is accepted three ways: a [`basic_json_view`](../basic_json_view/index.md) of *any* document -- read-only or
editable, and it does not have to be `array`'s own document -- which is copied so that nothing is shared with the
source document afterward; a `BasicJsonType` value; or anything `BasicJsonType` can be constructed from (numbers,
strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
has `push_back`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
## Template parameters
`V`
: the type of `value`, deduced; see above for what is accepted.
## Parameters
`array` (in)
: the array (or null value) to append to
`value` (in)
: the value to append
## Return value
a view of the new last element of `array`, now holding `value`
## Exception safety
Basic exception safety: `value` is fully encoded -- including the checks below -- into storage owned by the document
before anything already reachable from [`root()`](root.md) is touched, so a failure while encoding `value` (an
invalid argument, or `#!cpp std::bad_alloc`) leaves the document completely unchanged, other than memory allocated
for the encoding that is not reclaimed. A failure of a later allocation -- while `array` switches from its parsed
layout to a growable block, or while that block grows, see [Notes](#notes) -- can still leave a partial effect, such
as a null `array` argument already turned into an empty array even though `value` itself was not appended.
## Exceptions
Throws [`type_error.308`](../../home/exceptions.md#jsonexceptiontype_error308) if `array` is neither an array nor
null -- the same message [`BasicJsonType::push_back`](../basic_json/push_back.md) throws for the same type. Throws
[`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view does not belong to this
document") if `array` is a [discarded](../basic_json_view/is_discarded.md) view or a view of a *different* document.
Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if `value` is a
[discarded](../basic_json_view/is_discarded.md) view or a [discarded](../basic_json/is_discarded.md) `BasicJsonType`
value, and [`type_error.319`](../../home/exceptions.md#jsonexceptiontype_error319) if `value` is (or contains) a
binary value -- `BasicJsonType` can hold one, but a `json_document` cannot. Throws
[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) if `value` is (or contains) a string that is
not valid UTF-8, with the same message [`BasicJsonType::dump()`](../basic_json/dump.md) gives for that string.
## Complexity
Amortized constant, plus time linear in the size of `value` to encode it into the document's storage (constant for
a scalar, linear in the number of nested values for an array or object): the elements of `array` move to a growable
block of links the first time it is appended to (or [`set`](set.md) on), and that block itself grows -- doubling its
capacity, so the cost of growing it amortizes to constant per element -- only once it runs out of room. See
[Notes](#notes).
## Notes
Like [`set`](set.md) on a member or an element, `push_back` never moves an existing element itself -- only where
`array`'s *links* to its elements live -- so a view of an existing element of `array` stays valid across a
`push_back`, but any iterator already taken over `array` is invalidated, since it was walking the old layout. See
[Edits](index.md#edits) for what stays valid across an edit in general.
## Examples
??? example
The example below appends records to an array one at a time, as they might arrive from a stream of events,
without ever building a `BasicJsonType` value for the array or for the records already in it, and shows that a
view taken from an earlier `push_back` still refers to the same element once later ones have run.
```cpp
--8<-- "examples/basic_json_document__push_back.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__push_back.output"
```
## See also
- [set](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers to
- [insert](insert.md) - insert an element into an array before a given position
- [erase](erase.md) - remove an object member, an array element, or the value a JSON pointer refers to
- [root](root.md) - the view of the root value
- [`BasicJsonType::push_back`](../basic_json/push_back.md) - the corresponding function of `basic_json`
- [Edits](index.md#edits) - what an edit guarantees, for every overload
## Version history
- Added in version 3.13.0.
@@ -47,14 +47,7 @@ Every view taken from `#!cpp *this` before the call -- including the previous [`
whether or not the new parse succeeds; take fresh views from [`root()`](root.md) afterward.
`input` is borrowed or owned by the same rules as [`parse()`](parse.md#notes); a document can borrow on one call and
own on the next, since ownership is decided freshly each time. An input that is copied (see the table in
[`parse()`](parse.md#notes)) is written into the document's previous owned copy, reusing its memory; a moved-in
`#!cpp std::string` replaces it.
Reusing a document matters most for large inputs: the operating system provides the memory of a fresh node index one
page at a time, and every page costs a page fault the first time it is written. On x86-64 Linux (4 KiB pages), parsing
a 55 MB document into a reused document took about 40 % less time than parsing it into a fresh one. Programs that parse
many documents of similar size should therefore keep one document and call `read()`.
own on the next, since ownership is decided freshly each time.
An integer argument that is not a `#!cpp bool` where the flags are expected, such as `#!cpp read(ptr, len)`, does not
compile; see [`parse`](parse.md#notes).
@@ -80,7 +73,6 @@ compile; see [`parse`](parse.md#notes).
- [parse](parse.md) - deserialize from a compatible input
- [root](root.md) - the view of the root value
- [load](load.md) - read a document from an image instead of parsing JSON text
## Version history
@@ -39,8 +39,7 @@ auto v = doc.root();
`root()` is a cheap handle into the document's index, not a copy of anything; call it as often as needed. The
returned view is valid under the same conditions as any other view of the document -- see
[Object inspection](../basic_json_view/index.md) -- in particular, it is invalidated by the next
[`read()`](read.md) or [`shrink_to_fit()`](shrink_to_fit.md) on this document. A view can dangle, like a
`#!cpp std::string_view`; see [Ownership and lifetime](../../features/json_view.md#ownership-and-lifetime).
[`read()`](read.md) or [`shrink_to_fit()`](shrink_to_fit.md) on this document.
## Examples
@@ -1,104 +0,0 @@
# <small>nlohmann::basic_json_document::</small>save
```cpp
std::vector<std::uint8_t> save() const;
```
Writes the document as an *image*: a byte buffer that [`load`](load.md) reads back without parsing. The image holds
the node index, the source text (plus, for an edited document, the number tokens edits wrote), and the decoded
strings (plus the strings edits wrote) -- everything [`root()`](root.md) needs, with nothing left to parse.
An edited document is written in its *current* state, with its values in document order, the way the library's own
parser would have produced them for that JSON text: a member [`set`](set.md) added goes at the end, an
[`erase`](erase.md)d member leaves no trace, and a float that is not finite (NaN or positive/negative infinity)
becomes null, the same substitution [`dump()`](../basic_json_view/dump.md) makes. The same document always saves to
the same bytes -- also across `BasicJsonType` and `#!cpp Editable`, since the image reflects document order and
values only, not which specialization produced them.
## Return value
The image, as a `#!cpp std::vector<std::uint8_t>`. Pass it, or a pointer to its data together with its size, to
[`load`](load.md) to read the document back.
## Exception safety
Strong guarantee: `save()` does not modify `#!cpp *this` (it is `#!cpp const`), so if it throws, the document is left
exactly as it was, and the partially built image is discarded with the exception.
## Exceptions
Throws [`type_error.320`](../../home/exceptions.md#jsonexceptiontype_error320) if the document is
[discarded](is_discarded.md) -- a default-constructed document, or one a failed [`parse()`](parse.md)/
[`read()`](read.md) with `allow_exceptions == false` left discarded.
On a big-endian target, throws `type_error.320` with a different message instead: the image format is little-endian
only (see [Notes](#notes)).
Throws [`out_of_range.416`](../../home/exceptions.md#jsonexceptionout_of_range416) if the node count, the text, or
the decoded strings of the image would individually reach 4 GiB -- the same 32-bit offsets
[`parse()`](parse.md#exceptions) and, for edits, [`set`](set.md)/[`push_back`](push_back.md) are already limited to.
!!! failure "Example messages"
```
[json.exception.type_error.320] cannot save a discarded json_document
```
```
[json.exception.type_error.320] json_document images need a little-endian target
```
```
[json.exception.out_of_range.416] images of 4 GiB or more are not supported by json_document
```
## Complexity
Linear in the size of the document: the number of nodes, plus the length of the text and the decoded strings that end
up in the image.
## Notes
**Format.** The image begins with a 64-byte header (the magic bytes `#!cpp "NJVI"`, a version number, the node count,
and the sizes of the text and the decoded strings, all little-endian), followed by the nodes
([16 bytes each](../../home/architecture.md#node-index-of-json-views)), the text and a `#!cpp '\0'`, and the decoded
strings and a `#!cpp '\0'`. [`load`](load.md) checks the header, and the sizes it describes, before reading anything
else -- see [`load`'s Exceptions](load.md#exceptions).
!!! warning "Experimental"
The image format is versioned but not yet stable: it may change in an incompatible way before it is declared
stable. 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. Keep the original
JSON text if you need to read a saved document back with a future library version.
**Little-endian only.** The image is written as raw little-endian bytes, with no byte-swapping. `save()` (and
[`load`](load.md)) throw `type_error.320` on a big-endian target rather than silently produce bytes a big-endian
reader could not interpret correctly.
## Examples
??? example "Caching a parsed document as an image"
The example below saves a parsed configuration as an image -- the way a service might cache one to answer later
requests without parsing the text again -- and confirms that loading it back gives exactly the same result as
parsing did, and that saving is deterministic.
```cpp
--8<-- "examples/basic_json_document__save.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__save.output"
```
## See also
- [load](load.md) - read an image written by `save()`
- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
- [`basic_json_view::dump`](../basic_json_view/dump.md) - serialize the document to JSON text instead of an image
- [Images](../../features/json_view.md#images) - why and when to use images
## Version history
- Added in version 3.13.0.
@@ -1,203 +0,0 @@
# <small>nlohmann::basic_json_document::</small>set
```cpp
// (1)
template<typename V>
view_type set(view_type target, V&& value);
// (2)
template<typename V>
view_type set(view_type object, string_view_t key, V&& value);
// (3)
template<typename I, typename V>
view_type set(view_type array, I idx, V&& value);
// (4)
template<typename V>
view_type set(const json_pointer& ptr, V&& value);
```
Only an **editable** document (`#!cpp Editable == true`, e.g. [`json_editable_document`](../json_editable_document.md))
has `set`; calling it on a read-only `basic_json_document` fails to compile (`#!cpp static_assert`).
1. Replaces the value `target` refers to with `value`.
2. Sets the member `key` of the object `object` to `value`: assigns it if `object` already has a member with this
key -- the first one, should the key occur more than once, and the later duplicates are then dropped (see the
[Notes](#notes) below) -- or appends a new member at the end otherwise. A [null](../basic_json_view/is_null.md)
`object` first becomes an empty object.
3. Assigns `value` to the element at index `idx` of the array `array`, which must already exist (`#!cpp idx <
array.size()`).
4. Sets the value the JSON pointer `ptr` refers to, relative to [`root()`](root.md), to `value`. The *parent* of the
target must already exist: an object member is set as in 2. (added if it does not exist yet), an array element is
assigned as in 3., and a last reference token of `#!cpp "-"`, or equal to the size of the array, appends `value`
instead, exactly as [`push_back`](push_back.md) would. A [null](../basic_json_view/is_null.md) parent becomes what
[`basic_json::operator[]`](../basic_json/operator%5B%5D.md) with a JSON pointer makes of it: an array if the last
reference token is `#!cpp "-"` or consists of digits only (for an index beyond 0, the array is first filled with
null values up to that index), an object otherwise. An empty `ptr` sets [`root()`](root.md) itself, as in 1.
In every overload, `value` is accepted three ways: a [`basic_json_view`](../basic_json_view/index.md) of *any*
document -- read-only or editable, and it does not have to be `target`'s/`object`'s/`array`'s own document -- which
is copied so that nothing is shared with the source document afterward; a `BasicJsonType` value; or anything
`BasicJsonType` can be constructed from (numbers, strings, `#!cpp bool`, `#!cpp nullptr`, containers, ...).
## Template parameters
`V`
: the type of `value`, deduced; see above for what is accepted.
`I`
: an integral type other than `#!cpp bool`, deduced (overloads taking a `#!cpp bool` or a non-integral type for
`idx` do not participate in overload resolution).
## Parameters
`target` (in)
: the value to replace
`object` (in)
: the object (or null value) whose member to set
`array` (in)
: the array whose element to assign
`key` (in)
: the key of the member to set
`idx` (in)
: the index of the element to assign; a negative value throws (see [Exceptions](#exceptions))
`ptr` (in)
: a JSON pointer to the value to set, relative to `root()`
`value` (in)
: the new value
## Return value
1. a view of `target`, now holding `value`
2. a view of the member `key` of `object`, now holding `value`
3. a view of the element `idx` of `array`, now holding `value`
4. a view of the value `ptr` refers to, now holding `value`
## Exception safety
Basic exception safety: `value` is fully encoded -- including the checks below -- into storage owned by the document
before anything already reachable from [`root()`](root.md) is touched, so a failure while encoding `value` (an
invalid argument, or `#!cpp std::bad_alloc`) leaves the document completely unchanged, other than memory allocated
for the encoding that is not reclaimed. A failure of a later allocation -- while an edited array or object switches
from its parsed layout to a growable block, see [Notes](#notes) -- can still leave a partial effect, such as a
[null](../basic_json_view/is_null.md) `object`/`array` argument already turned into an empty object/array even
though `value` itself was not linked in. Likewise, a failure of `value` in 4. leaves a null parent that is set with an
index beyond 0 already filled with the null values before the index.
## Exceptions
1. Throws [`type_error.302`](../../home/exceptions.md#jsonexceptiontype_error302) if `value` is a
[discarded](../basic_json_view/is_discarded.md) view, or a [discarded](../basic_json/is_discarded.md)
`BasicJsonType` value (e.g. `#!cpp BasicJsonType(value_t::discarded)`) -- an object or array `value`, of either
kind, is fine and is encoded as a whole subtree.
2. Throws [`type_error.305`](../../home/exceptions.md#jsonexceptiontype_error305) if `object` is neither an object
nor null -- the same message [`operator[]`](../basic_json_view/operator%5B%5D.md) throws for a string argument on
such a value. Throws [`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316) if `key` is not
valid UTF-8, with the same message [`BasicJsonType::dump()`](../basic_json/dump.md) gives for that string.
Also throws what 1. throws for `value`.
3. Throws `type_error.305` if `array` is not an array -- the same message `operator[]` throws for a numeric argument
on such a value. Throws [`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if `idx` is
negative, or if `#!cpp idx >= array.size()`. Also throws what 1. throws for `value`.
4. Throws what [`at`](../basic_json_view/at.md) throws (overload 3) for resolving `ptr`'s parent, except that a
missing object member or an array index equal to the array's size at the very last reference token is not an
error there (it becomes a new member or an appended element) instead of
[`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403)/[`out_of_range.402`](../../home/exceptions.md#jsonexceptionout_of_range402).
For the last reference token itself: if the parent is an object (or a primitive value, where it throws
`type_error.305`), throws what 2. throws; if the parent is an array, throws what 3. throws for an index that is
out of range, or, for a token that is not a valid array index,
[`parse_error.106`](../../home/exceptions.md#jsonexceptionparse_error106) (a leading `#!cpp '0'`),
[`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) (not a number),
[`out_of_range.410`](../../home/exceptions.md#jsonexceptionout_of_range410) (too large for `size_type`), or
[`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) (an empty token); the same errors are
thrown for a null parent and a token of digits (the parent is not changed then), and
[`out_of_range.401`](../../home/exceptions.md#jsonexceptionout_of_range401) if the index is 4294967295 or more.
Also throws what 1. throws for `value`.
Every overload also throws [`type_error.319`](../../home/exceptions.md#jsonexceptiontype_error319) if `value` is (or
contains) a binary value -- `BasicJsonType` can hold one, but a `json_document` cannot -- and
[`invalid_iterator.202`](../../home/exceptions.md#jsonexceptioninvalid_iterator202) ("view does not belong to this
document") if `target`/`object`/`array` is a [discarded](../basic_json_view/is_discarded.md) view or a view of a
*different* document (overloads 1-3 only; overload 4 always starts from this document's own [`root()`](root.md)).
## Complexity
1. Linear in the size of `value` (encoding it into the document's storage): constant for a scalar, linear in the
number of nested values for an array or object. If `target` is itself an array or object that spans more than one
node in its parent's original, unedited layout, and `value` is a scalar, replacing it additionally costs time
linear in the size of the document, the *first* time (the parent of `target` is looked up from
[`root()`](root.md), and then switches to links) -- see [Notes](#notes). Once the parent has links, `target` is
replaced in constant time: setting every element of a large array one after the other is linear overall. To avoid
the lookup altogether, use 3. (or 2. for an object), which know the parent.
2. Linear in the number of members of `object`, to find an existing member with `key`, plus the complexity of 1. for
`value`.
3. Constant, plus the complexity of 1. for `value`.
4. 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 [`at`](../basic_json_view/at.md)), plus the complexity of 2. or 3. for
the last token; for a null parent and an index, linear in the index.
## Notes
!!! info "Duplicate keys"
If `object` already has more than one member with `key` (2.), the *first* one is assigned `value` and every
later member with the same key is removed -- so that a lookup, an iteration, and
[`materialize()`](../basic_json_view/materialize.md) of `object` afterward all agree on a single value for
`key`, the same way [`operator[]`](../basic_json_view/operator%5B%5D.md) already picks the first occurrence of a
duplicate key for reading. See the [Notes on duplicate keys](../basic_json_view/operator%5B%5D.md#notes) of
`operator[]`.
Setting a member (2.) or an element (3., through 4.) of an array or object whose elements have not been edited
before switches it from its parsed layout to a growable block holding links to its elements; a later
[`push_back`](push_back.md) or `set` on the same container reuses that block, growing it (amortized constant time)
only once it runs out of room. This never moves an element itself -- only where the container's *links* to its
elements live -- so a view of an element stays valid, but any iterator already taken over the container is
invalidated, since it was walking the old layout. See [Edits](index.md#edits) for what stays valid across an edit in
general.
The same switch happens, for the same reason, when overload 1. replaces a multi-node array/object value with a
scalar: the *parent's* element sequence is what has to switch to links, not `target` itself, because the parent
originally stepped over `target`'s whole subtree by its node count, which no longer applies once `target` is a
one-node scalar.
## Examples
??? example "Example: (1)/(2)/(3)/(4) replace a value, set a member, assign an element, set via a JSON pointer"
The example below edits a small configuration document -- replacing a value, adding an object member, assigning
an array element, and reaching a field through a JSON pointer -- and shows what
[`dump()`](../basic_json_view/dump.md) preserves that is lost once the same edits are made on a `BasicJsonType`
value instead: the order object members were written in, and the exact spelling of a number that was never
touched.
```cpp
--8<-- "examples/basic_json_document__set.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__set.output"
```
## See also
- [push_back](push_back.md) - append to an array
- [insert](insert.md) - insert an element into an array
- [erase](erase.md) - remove an object member, an array element, or the value a JSON pointer refers to
- [root](root.md) - the view of the root value, the starting point of overload 4
- [`basic_json_view::dump`](../basic_json_view/dump.md) - serialize the document, keeping an untouched number's
spelling with `#!cpp number_format::source`
- [Edits](index.md#edits) - what an edit guarantees, for every overload
- [Editing a document](../../features/json_view.md#editing-a-document) - why editable documents keep the source
text's order and number spelling
## Version history
- Added in version 3.13.0.
+1 -3
View File
@@ -41,7 +41,7 @@ basic_json_view at(const json_pointer& ptr) const;
## Exception safety
Strong guarantee: there are no changes to the view or the document it refers to.
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
## Exceptions
@@ -77,8 +77,6 @@ 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 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
+3 -2
View File
@@ -13,7 +13,7 @@ The last element or member value. For a primitive value (number, string, boolean
## Exception safety
Strong guarantee: there are no changes to the view or the document it refers to.
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
## Exceptions
@@ -33,7 +33,8 @@ index.
## Notes
Unlike [`BasicJsonType::back()`](../basic_json/back.md), which has undefined behavior for an empty array or object,
`back()` throws `invalid_iterator.214` for an empty array, an empty object, a null value, or a discarded view.
`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.
## Examples
@@ -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), and a `#!json null` value or a [discarded](is_discarded.md) view iterates as an empty range.
element (itself); `#!json null` and a [discarded](is_discarded.md) view iterate 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), and [`contains`](contains.md),
[`operator[]`](operator[].md), [`at`](at.md), [`find`](find.md), [`contains`](contains.md), and [`count`](count.md),
which all resolve to the *first* member with a given key. See the
[Notes on duplicate keys](operator[].md#notes) of `operator[]`.
@@ -31,10 +31,6 @@ 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
@@ -35,8 +35,6 @@ 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 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.
@@ -55,8 +53,7 @@ view.
!!! info "Postconditions"
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
If `#!cpp v.contains(key)` returns `#!cpp true`, then `#!cpp v[key]` is not [discarded](is_discarded.md). If
`#!cpp v.contains(ptr)` returns `#!cpp true`, then `#!cpp v[ptr]` is not discarded and `#!cpp v.at(ptr)` does not
throw.
+19 -17
View File
@@ -6,8 +6,7 @@ size_type count(const char* key) const;
size_type count(const string_t& key) const;
```
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.
Returns `#!cpp 1` if the value is an object with a member with key `key`, `#!cpp 0` otherwise.
## Parameters
@@ -16,8 +15,7 @@ key are all counted.
## Return value
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.
`#!cpp 1` if the value is an object and has a member with key `key`, `#!cpp 0` otherwise.
## Exception safety
@@ -25,30 +23,34 @@ No-throw guarantee: this function never throws exceptions.
## Complexity
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.
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.
## 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.
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[]`.
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).
## Examples
??? example
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.
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.
```cpp
--8<-- "examples/basic_json_view__count.cpp"
@@ -1,104 +0,0 @@
# <small>nlohmann::basic_json_view::</small>dump
```cpp
string_t dump(const int indent = -1,
const char indent_char = ' ',
const bool ensure_ascii = false,
const number_format numbers = number_format::shortest) const;
```
Serializes this value (and its subtree) directly from the flat index, without ever building a `BasicJsonType` value
first. With the default `#!cpp numbers == number_format::shortest`, the result is the same string
[`BasicJsonType::dump`](../basic_json/dump.md) would produce for the value
[`BasicJsonType::parse()`](../basic_json/parse.md) builds from the same source text, called with the same `indent`,
`indent_char`, and `ensure_ascii` -- except that members of an object appear in document order rather than sorted by
key, and *every* occurrence of a repeated key is written rather than only the last one (see
[Notes on duplicate keys](operator[].md#notes)). For a `json_view` (whose `BasicJsonType` is not ordered), this means
`dump()` can print an object's members in a different order than [`materialize()`](materialize.md)`.dump()` of the
same subtree.
## Parameters
`indent` (in)
: If `indent` is nonnegative, array elements and object members are pretty-printed with that indent level. An
indent level of `0` only inserts newlines. `-1` (the default) selects the most compact representation.
`indent_char` (in)
: The character used for indentation if `indent` is greater than `0`. The default is ` ` (space).
`ensure_ascii` (in)
: If `ensure_ascii` is `#!cpp true`, all non-ASCII characters in the output are escaped with `\uXXXX` sequences, and
the result consists of ASCII characters only.
`numbers` (in)
: how to write numbers, see [`number_format`](number_format.md): `shortest` (the default) writes them the way
[`BasicJsonType::dump`](../basic_json/dump.md) would; `source` copies every number exactly as it appears in the
source text.
## Return value
string containing the serialization of this value, or `#!cpp "<discarded>"` if the view is
[discarded](is_discarded.md).
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
## Exceptions
May throw `#!cpp std::bad_alloc` if allocating the output string fails. Unlike
[`BasicJsonType::dump`](../basic_json/dump.md), there is no `error_handler` parameter and no
[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316): the view only ever holds text the parser
already validated as UTF-8, so there is nothing to replace or ignore.
## Complexity
Linear in the size of the output text.
## Notes
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,
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
[What is different](../../features/json_view.md#what-is-different)) -- something `BasicJsonType` cannot do, since
parsing already reduces every number to its parsed value.
## Examples
??? example
The example below forwards a single record out of a larger batch, and re-serializes a configuration file, both
without ever building a `BasicJsonType` value for the surrounding array or for the parts of it that were not
needed. It also shows that [`materialize()`](materialize.md)`.dump()` of the configuration sorts its keys, where
`dump()` on the view keeps the order they appear in the source text.
```cpp
--8<-- "examples/basic_json_view__dump.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__dump.output"
```
## See also
- [`number_format`](number_format.md) - how `dump()` writes numbers
- [operator<<](operator_ltlt.md) - serialize this value to a stream
- [materialize](materialize.md) - build a `BasicJsonType` value, e.g. to use `BasicJsonType::dump`'s `error_handler`
- [`BasicJsonType::dump`](../basic_json/dump.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
+3 -2
View File
@@ -5,8 +5,9 @@ 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), and a
`#!json null` value or a [discarded](is_discarded.md) view iterates as an empty range (`#!cpp begin() == end()`).
**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.
## Return value
@@ -28,8 +28,6 @@ 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 of their keys while parsing, so that a lookup in them takes
constant time on average.
## Notes
@@ -13,7 +13,7 @@ The first element or member value. For a primitive value (number, string, boolea
## Exception safety
Strong guarantee: there are no changes to the view or the document it refers to.
Strong exception safety: if an exception is thrown, 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` for an empty array, an empty object, a null value, or a discarded
view.
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.
## Examples
+7 -10
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` (for a boolean, `#!cpp 0`/`#!cpp 1`, exactly as for
[`BasicJsonType::get<T>()`](../basic_json/get.md))
- 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)
- `#!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>` -- from an array, element by element, each converted with `#!cpp get<U>()`; `#!cpp
- `#!cpp std::vector<U, A>` -- 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 -- from an object, member by member, each value converted with `#!cpp get<V>()`; with a repeated
(const char*, std::size_t)` pair -- 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 guarantee: there are no changes to the view or the document it refers to.
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
## Exceptions
@@ -62,9 +62,6 @@ 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
@@ -76,8 +73,8 @@ document.
- `#!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`: the cost of [`materialize()`](materialize.md) and of destroying the `BasicJsonType` value
afterwards, plus that of [`BasicJsonType::get<T>()`](../basic_json/get.md).
- 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.
## Notes
@@ -15,7 +15,7 @@ had to be decoded once when the document was parsed).
## Exception safety
Strong guarantee: there are no changes to the view or the document it refers to.
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
## Exceptions
@@ -37,14 +37,9 @@ 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, 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.
source text.
## Examples
+8 -23
View File
@@ -5,15 +5,12 @@ template<typename T>
T& get_to(T& v) const;
```
Converts the value to `T` and stores it in `v`, in one of two ways:
Converts the value to `T` and assigns it to `v`. Equivalent to
- 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.
```cpp
v = get<T>();
return v;
```
## Template parameters
@@ -31,27 +28,15 @@ Converts the value to `T` and stores it in `v`, in one of two ways:
## Exception safety
- 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.
Strong exception safety: if an exception is thrown, `v` is not modified.
## Exceptions
- 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.
Whatever [`get<T>()`](get.md) throws for the same value and `T`.
## Complexity
- 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`.
Whatever [`get<T>()`](get.md) has for the same `T`.
## Examples
+9 -43
View File
@@ -3,7 +3,7 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
template<typename BasicJsonType, bool Editable = false>
template<typename BasicJsonType>
class basic_json_view;
```
@@ -14,34 +14,17 @@ 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 and unmodified (floating-point values and
unescaped strings are read from it lazily).
- if the document borrows its source text, that text is still alive.
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: [`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
[`basic_json_document::set`](../basic_json_document/set.md) and
[`basic_json_document::push_back`](../basic_json_document/push_back.md): once a value is changed, every view that
still refers to it -- including ones taken before the change -- reads the new value. See
[Edits](../basic_json_document/index.md#edits).
`basic_json_view` provides the read-only part of the `BasicJsonType` interface: the type-inspection functions, element
access, lookup, iteration, and 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. [`operator[]`](operator%5B%5D.md), [`at`](at.md), [`contains`](contains.md), and
[`value`](value.md) also accept a [`json_pointer`](../json_pointer/index.md). It does not (yet) provide `dump()` or
comparison.
## Template parameters
@@ -49,17 +32,10 @@ still refers to it -- including ones taken before the change -- reads the new va
: a specialization of [`basic_json`](../basic_json/index.md), matching the
[`basic_json_document`](../basic_json_document/index.md) the view was taken from.
`Editable`
: whether the view is of an editable document, matching the [`basic_json_document`](../basic_json_document/index.md)
it was taken from (optional, `#!cpp false` by default). See [Edits](../basic_json_document/index.md#edits).
## Specializations
- [**json_view**](../json_view.md) - views of a [`json_document`](../json_document.md)
- [**ordered_json_view**](../ordered_json_view.md) - views of an [`ordered_json_document`](../ordered_json_document.md)
- [**json_editable_view**](../json_editable_view.md) - views of a [`json_editable_document`](../json_editable_document.md)
- [**ordered_json_editable_view**](../ordered_json_editable_view.md) - views of an
[`ordered_json_editable_document`](../ordered_json_editable_document.md)
## Member types
@@ -70,7 +46,7 @@ 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
- [**number_format**](number_format.md) - how [`dump()`](dump.md) writes numbers
- **item** - a (key, value) pair produced by [`items()`](items.md)
## Member functions
@@ -129,16 +105,6 @@ still refers to it -- including ones taken before the change -- reads the new va
- [**number_token**](number_token.md) - get a number's token text without a copy
- [**materialize**](materialize.md) - build the `BasicJsonType` value of this subtree
### Comparison
- [**operator==**](operator_eq.md) - comparison: equal
- [**operator!=**](operator_ne.md) - comparison: not equal
### Serialization
- [**dump**](dump.md) - serialize to a JSON-formatted string
- [**operator<<**](operator_ltlt.md) - serialize to stream
### Source access
- [**source_offset**](source_offset.md) - byte offset of this value in the document's source text
@@ -38,8 +38,7 @@ Constant.
## See also
- [is_structured](is_structured.md) - return whether the type is structured
- [size](size.md) - the number of elements
- [empty](empty.md) - whether there are no elements
- [size](size.md), [empty](empty.md) - the number of elements, and whether there are none
- [`BasicJsonType::is_array`](../basic_json/is_array.md) - the corresponding function of `basic_json`
## Version history
@@ -4,9 +4,8 @@
bool is_binary() const noexcept;
```
This function always returns `#!cpp false`: a document is only ever parsed from JSON text, never from CBOR or the other
binary formats, and a JSON text has no binary values, so a view can never refer to one. The function exists for
interface parity with [`BasicJsonType::is_binary`](../basic_json/is_binary.md).
This function always returns `#!cpp false`: a JSON text has no binary values, so a view can never refer to one. The
function exists for interface parity with [`BasicJsonType::is_binary`](../basic_json/is_binary.md).
## Return value
@@ -15,7 +15,7 @@ JSON pointer that cannot be resolved, and for any access on a view that is itsel
## Return value
`#!cpp true` if the view or its document is discarded, `#!cpp false` otherwise.
`#!cpp true` if the view is discarded, `#!cpp false` otherwise.
## Exception safety
@@ -38,8 +38,7 @@ Constant.
## See also
- [is_structured](is_structured.md) - return whether the type is structured
- [size](size.md) - the number of elements
- [empty](empty.md) - whether there are no elements
- [size](size.md), [empty](empty.md) - the number of elements, and whether there are none
- [`BasicJsonType::is_object`](../basic_json/is_object.md) - the corresponding function of `basic_json`
## Version history
@@ -37,8 +37,7 @@ Constant.
## See also
- [source_offset](source_offset.md) - byte offset of this value in the source text, which differs for strings: an
escaped string has none
- [source_offset](source_offset.md) - byte offset of this value in the document's source text
- [`BasicJsonType::is_string`](../basic_json/is_string.md) - the corresponding function of `basic_json`
## Version history
@@ -4,9 +4,9 @@
/* unspecified */ items() const noexcept;
```
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.
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).
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 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.
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.
## 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),
and [`contains`](contains.md), which resolve to the *first* member with a given key. See the
[`contains`](contains.md), and [`count`](count.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"
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.
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.
## Examples
@@ -14,8 +14,8 @@ if the view is [discarded](is_discarded.md).
## Exception safety
Strong guarantee: there are no changes to the view or the document it refers to (nothing about either is mutated by
this function).
Strong guarantee: if an exception is thrown, there are no changes to the view or the document it refers to (nothing
about either is mutated by this function).
## Exceptions
@@ -28,13 +28,12 @@ Linear in the size of the subtree.
## Notes
`materialize()` replays the subtree through the same SAX builder [`BasicJsonType::parse()`](../basic_json/parse.md)
uses, so the result matches it exactly -- including, for an object, that a repeated key keeps only its
uses internally, so the result matches it exactly -- including, for an object, that a repeated key keeps only its
last value. The replay is iterative, so it is not limited by the call stack the way a naive recursive conversion
would be; the JSON nesting depth is limited only by available memory, as for `BasicJsonType::parse()` itself.
Unlike parsing with [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) enabled, the values
produced by `materialize()` do not carry source positions. The index has the start offset of every value, but not the
end of arrays, objects, and escaped strings, which the positions also need.
produced by `materialize()` do not carry source positions: there is no lexer run during the replay to record them.
Calling `materialize()` on the same view repeatedly builds a new, independent `BasicJsonType` value each time; it
never caches the result.
@@ -1,51 +0,0 @@
# <small>nlohmann::basic_json_view::</small>number_format
```cpp
enum class number_format {
shortest,
source
};
```
This enumeration is used in [`dump`](dump.md) to choose how numbers are written. Two values are differentiated:
shortest
: integers are copied from the source text -- already canonical in JSON -- except that `#!cpp -0` becomes
`#!cpp 0`, the way [`BasicJsonType::parse()`](../basic_json/parse.md) reads it; 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`)
source
: every number is copied exactly as it appears in the source text -- `#!cpp 1.50`, `#!cpp 1E2`, `#!cpp -0`, all
digits of an integer literal with more digits than any number type holds -- something `BasicJsonType` cannot do,
since parsing already reduces every number to its parsed value
## Examples
??? example
The example below writes back a price list received from a supplier: with `number_format::shortest` (the
default), a trailing zero and scientific notation are normalized away and a long account number that overflows
every number type is rounded, the same way `#!cpp materialize().dump()` (or `basic_json::dump()`) would;
`number_format::source` keeps every number exactly as it was written in the source text instead.
```cpp
--8<-- "examples/basic_json_view__number_format.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__number_format.output"
```
## See also
- [dump](dump.md) - serialize to a JSON-formatted string
- [number_token](number_token.md) - get a single number's token text without dumping the whole value
- [`BasicJsonType::error_handler_t`](../basic_json/error_handler_t.md) - the analogous enumeration for
`BasicJsonType::dump`'s decoding-error behavior
## Version history
- Added in version 3.13.0.
@@ -15,7 +15,7 @@ and [`materialize()`](materialize.md) can only represent approximately, as a `nu
## Exception safety
Strong guarantee: there are no changes to the view or the document it refers to.
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
## Exceptions
@@ -50,7 +50,7 @@ basic_json_view operator[](const json_pointer& ptr) const;
## Exception safety
Strong guarantee: there are no changes to the view or the document it refers to.
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
## Exceptions
@@ -83,8 +83,6 @@ 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 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 +108,12 @@ 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), [`value`](value.md), and JSON pointer resolution) all resolve to
[`contains`](contains.md), [`count`](count.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 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).
@@ -1,109 +0,0 @@
# <small>nlohmann::basic_json_view::</small>operator==
```cpp
// (1)
bool operator==(const basic_json_view& lhs, const basic_json_view& rhs);
// (2)
bool operator==(const basic_json_view& lhs, const BasicJsonType& rhs);
bool operator==(const BasicJsonType& lhs, const basic_json_view& rhs);
```
1. Compares two views for equality: whether the values [`BasicJsonType::parse()`](../basic_json/parse.md) would
produce for `lhs` and `rhs` are equal, according to `BasicJsonType`'s [`operator==`](../basic_json/operator_eq.md).
2. Compares a view and a `BasicJsonType` value for equality, in either order: whether the value `parse()` would
produce for the view and the other operand are equal, according to `BasicJsonType`'s
[`operator==`](../basic_json/operator_eq.md).
Neither overload builds a `BasicJsonType` value for a view to do the comparison (see [Notes](#notes) below). Numbers
compare by value across their types (`#!cpp 1 == 1.0`), and an object compares by its members, with duplicate keys
resolved exactly as `parse()` resolves them -- the last value, at the position of the first occurrence of the key.
This is not what [`operator[]`](operator[].md) and the other lookups return for a duplicate key: they find the *first*
member (see [Duplicate keys](../../features/json_view.md#duplicate-keys)).
## Parameters
`lhs` (in)
: first value to consider
`rhs` (in)
: second value to consider
## Return value
whether the values `lhs` and `rhs` are equal
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to either operand, or to the document(s) a
view refers to.
## Exceptions
May throw `#!cpp std::bad_alloc`. Unlike the other comparison and most other `basic_json_view` functions,
`operator==` is not `#!cpp noexcept`: resolving an object's members needs a temporary array to sort them by key (see
[Complexity](#complexity) below), and that allocation can fail.
## Complexity
Linear in the size of the compared values: every number, string, array element, and object member is visited at most
once, and the walk is iterative, so the nesting depth it can compare is limited by available memory only, not by the
call stack (as for [`materialize()`](materialize.md)). Resolving an object's members takes an additional O(n log n)
in the number of members at that level, since they are sorted by key to detect and resolve duplicates before being
compared. Two arrays of different [`size()`](size.md) are rejected without visiting either one's elements.
## Notes
Only a single number, boolean, or `#!cpp null` value is ever materialized into a `BasicJsonType`, to reuse its
`operator==` -- for numbers, so that values written differently in the source text but equal in value (e.g. an
integer and a floating-point literal) still compare equal, following the same rules `BasicJsonType` does for special
values such as `#!cpp NaN`. Constructing one of these scalars never allocates. Strings are compared directly, without
allocating, either from the source text on both sides or, for overload 2, against `BasicJsonType`'s own string.
Arrays and objects are never materialized at all; only their elements or members are visited, one pair at a time.
!!! info "How objects are compared"
For a [`json_view`](../json_view.md) (`BasicJsonType::object_t` is `#!cpp std::map`), members are compared by
key, regardless of the order they appear in the source text. For an
[`ordered_json_view`](../ordered_json_view.md) (`object_t` is `ordered_map`), they are compared in the order
they occur, so the very same two objects with their members reordered can compare equal as `json_view`s but not
as `ordered_json_view`s. This is exactly how [`json`](../json.md) and [`ordered_json`](../ordered_json.md)
compare, see ["Comparing different `basic_json` specializations"](../basic_json/operator_eq.md#notes).
!!! info "Discarded views"
A [discarded](is_discarded.md) view compares the same way a discarded `BasicJsonType` value does, which is
governed by
[`JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON`](../macros/json_use_legacy_discarded_value_comparison.md): by
default, a discarded view is never equal to anything, not even another discarded view.
No ordering comparison (`#!cpp operator<`) is provided for `basic_json_view`; [`materialize()`](materialize.md) is
the way to get a `BasicJsonType` value that supports it.
## Examples
??? example
The example below checks whether a newly received configuration differs from the previous one, and whether a
received document matches what a test expects -- directly on views, without ever materializing a `BasicJsonType`
value for either side.
```cpp
--8<-- "examples/basic_json_view__operator_eq.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__operator_eq.output"
```
## See also
- [operator!=](operator_ne.md) - compare for inequality
- [materialize](materialize.md) - build a `BasicJsonType` value, e.g. to keep comparing after the document is gone
- [`BasicJsonType::operator==`](../basic_json/operator_eq.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,74 +0,0 @@
# <small>nlohmann::basic_json_view::</small>operator<<
```cpp
std::ostream& operator<<(std::ostream& o, const basic_json_view& v);
```
Not available when [`JSON_NO_IO`](../macros/json_no_io.md) is defined.
Serializes the given view `v` to the output stream `o`, using [`dump`](dump.md) -- exactly as
`#!cpp operator<<(std::ostream&, const basic_json&)` does for a `basic_json` value.
- The indentation of the output can be controlled with the member variable `width` of the output stream `o`. For
instance, using the manipulator `std::setw(4)` on `o` sets the indentation level to `4`, and the serialization
result is the same as calling `#!cpp v.dump(4)`. A `width` of `0` or less (the default) selects the most compact
representation, as `#!cpp v.dump(-1)` does.
- The indentation character can be controlled with the member variable `fill` of the output stream `o`. For instance,
the manipulator `std::setfill('\t')` sets indentation to use a tab character rather than the default space
character.
- As for `basic_json`, `o`'s `width` is reset to `0` after this call, whether or not it was greater than `0` before.
Numbers are always written as `#!cpp v.dump()` writes them by default, i.e. as with
[`number_format::shortest`](number_format.md); there is no way to select `#!cpp number_format::source` through the
stream.
## Parameters
`o` (in, out)
: stream to write to
`v` (in)
: view to serialize
## Return value
the stream `o`
## Exceptions
May throw `#!cpp std::bad_alloc`, propagated from [`dump`](dump.md#exceptions). Unlike
`#!cpp operator<<(std::ostream&, const basic_json&)`, there is no UTF-8 decoding step that could throw
[`type_error.316`](../../home/exceptions.md#jsonexceptiontype_error316), and no `error_handler` to choose between --
see the [Exceptions](dump.md#exceptions) of `dump`.
## Complexity
Linear, as [`dump`](dump.md#complexity).
## Examples
??? example
The example below writes one record out of a larger batch straight to a log stream -- compact for a one-line
entry, and pretty-printed with `std::setw`/`std::setfill` for a readable dump -- without ever building a
`BasicJsonType` value for the record, or for the rest of the batch.
```cpp
--8<-- "examples/basic_json_view__operator_ltlt.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__operator_ltlt.output"
```
## See also
- [dump](dump.md) - serialize to a JSON-formatted string
- [`operator<<(std::ostream&)`](../operator_ltlt.md) - the corresponding operator for `basic_json`
- [`JSON_NO_IO`](../macros/json_no_io.md) - switch off functions relying on certain C++ I/O headers
## Version history
- Added in version 3.13.0.
@@ -1,82 +0,0 @@
# <small>nlohmann::basic_json_view::</small>operator!=
```cpp
// (1)
bool operator!=(const basic_json_view& lhs, const basic_json_view& rhs);
// (2)
bool operator!=(const basic_json_view& lhs, const BasicJsonType& rhs);
bool operator!=(const BasicJsonType& lhs, const basic_json_view& rhs);
```
1. Compares two views for inequality. Returns `#!cpp !(lhs == rhs)`, see [operator==](operator_eq.md).
2. Compares a view and a `BasicJsonType` value for inequality, in either order. Returns `#!cpp !(lhs == rhs)` (or,
for the reversed order, `#!cpp !(rhs == lhs)`), see [operator==](operator_eq.md).
Since `operator!=` is defined as the negation of [`operator==`](operator_eq.md), it follows the same rules for
special cases: for instance, since a [discarded](is_discarded.md) view is never equal to anything by default (see
[operator=='s Notes](operator_eq.md#notes)), it is never *unequal* to anything either -- `#!cpp discarded != discarded`
is also `#!cpp false`, exactly as for a discarded `BasicJsonType` value.
## Parameters
`lhs` (in)
: first value to consider
`rhs` (in)
: second value to consider
## Return value
whether the values `lhs` and `rhs` are not equal
## Exception safety
Strong exception safety: if an exception is thrown, there are no changes to either operand, or to the document(s) a
view refers to.
## Exceptions
May throw `#!cpp std::bad_alloc`, propagated from [`operator==`](operator_eq.md#exceptions). Unlike most other
`basic_json_view` functions, `operator!=` is not `#!cpp noexcept`.
## Complexity
Linear, as [`operator==`](operator_eq.md#complexity).
## Notes
See the [Notes](operator_eq.md#notes) of `operator==` -- in particular for how an object's members are compared
(order matters for [`ordered_json_view`](../ordered_json_view.md) but not for [`json_view`](../json_view.md)) and
for how discarded views compare.
No ordering comparison (`#!cpp operator<`) is provided for `basic_json_view`; [`materialize()`](materialize.md) is
the way to get a `BasicJsonType` value that supports it.
## Examples
??? example
The example below asserts, as a test would, that a received document differs from an unwanted value, and shows
that -- as for [`json`](../json.md)/[`ordered_json`](../ordered_json.md) -- reordering an object's members is
detected as a difference for an `ordered_json_view` but not for a `json_view`.
```cpp
--8<-- "examples/basic_json_view__operator_ne.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__operator_ne.output"
```
## See also
- [operator==](operator_eq.md) - compare for equality
- [materialize](materialize.md) - build a `BasicJsonType` value, e.g. to keep comparing after the document is gone
- [`BasicJsonType::operator!=`](../basic_json/operator_ne.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
+9 -9
View File
@@ -10,15 +10,15 @@ Returns the number of elements, as [`BasicJsonType::size()`](../basic_json/size.
The return value depends on the type and is defined as follows:
| Value type | return value |
|------------|---------------------------|
| null | `0` |
| discarded | `0` |
| boolean | `1` |
| string | `1` |
| number | `1` |
| object | number of key/value pairs |
| array | number of elements |
| Value type | return value |
|----------------------|-----------------------------|
| null | `0` |
| discarded | `0` |
| boolean | `1` |
| string | `1` |
| number | `1` |
| object | number of key/value pairs |
| array | number of elements |
## Exception safety
@@ -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
@@ -44,7 +44,7 @@ equivalent) deduce `string_t`, not `const char*`, for their return type and for
## Exception safety
Strong guarantee: there are no changes to the view or the document it refers to.
Strong exception safety: if an exception is thrown, there are no changes to the view or the document it refers to.
## Exceptions
@@ -70,8 +70,6 @@ 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 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
@@ -1,43 +0,0 @@
# <small>nlohmann::</small>json_editable_document
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using json_editable_document = basic_json_document<json, true>;
```
This type is an **editable** [`basic_json_document`](basic_json_document/index.md) of the default
[`json`](json.md) specialization: in addition to everything [`json_document`](json_document.md) offers,
[`set`](basic_json_document/set.md) and [`push_back`](basic_json_document/push_back.md) change values after
parsing, without ever rewriting the source text -- see [Edits](basic_json_document/index.md#edits) and
[Editing a document](../features/json_view.md#editing-a-document).
## Examples
??? example
The example below patches two fields of a small configuration document -- changing one and adding another --
and dumps it back out with the member order and the spelling of the untouched number preserved, something a
plain [`json`](json.md) value cannot do.
```cpp
--8<-- "examples/json_editable_document.cpp"
```
Output:
```json
--8<-- "examples/json_editable_document.output"
```
## See also
- [json_editable_view](json_editable_view.md) - a view of a value of a `json_editable_document`
- [json_document](json_document.md) - the read-only document this type adds edits to
- [ordered_json_editable_document](ordered_json_editable_document.md) - the corresponding editable document for
`ordered_json`
- [Edits](basic_json_document/index.md#edits) - what an edit guarantees
## Version history
Since version 3.13.0.
@@ -1,41 +0,0 @@
# <small>nlohmann::</small>json_editable_view
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using json_editable_view = basic_json_view<json, true>;
```
This type is a [`basic_json_view`](basic_json_view/index.md) of a value of a
[`json_editable_document`](json_editable_document.md). It offers the same read-only interface as
[`json_view`](json_view.md); what is different is what it can be a view *of* -- a value that
[`set`](basic_json_document/set.md) and [`push_back`](basic_json_document/push_back.md) can change, with every view
still referring to it seeing the change, see [Edits](basic_json_document/index.md#edits).
## Examples
??? example
The example below is the same as [`json_editable_document`'s](json_editable_document.md): every view read back
out of the document -- `#!cpp doc.root()` and the views nested under it -- sees the edits made through `set`.
```cpp
--8<-- "examples/json_editable_document.cpp"
```
Output:
```json
--8<-- "examples/json_editable_document.output"
```
## See also
- [json_editable_document](json_editable_document.md) - the document type this view refers into
- [json_view](json_view.md) - the corresponding read-only view
- [ordered_json_editable_view](ordered_json_editable_view.md) - the corresponding view for
`ordered_json_editable_document`
## Version history
Since version 3.13.0.
-6
View File
@@ -16,10 +16,6 @@ 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,
@@ -42,8 +38,6 @@ header. See also the [macro overview page](../../features/macros.md).
- [**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
- [**JSON_USE_SIMDUTF**](json_use_simdutf.md) - use the simdutf library to accelerate UTF-8 validation
- [**JSON_VIEW_NO_SIMD**](json_view_no_simd.md) - use only portable code in the parser of `json_view.hpp`
- [**JSON_VIEW_USE_SSSE3**](json_view_use_ssse3.md) - validate non-ASCII strings with SSSE3 in the parser of `json_view.hpp`
## Library version
@@ -1,144 +0,0 @@
# 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.
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