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Author SHA1 Message Date
Niels Lohmann 8fb114e45f Bump Semgrep to 1.182.1 and allow two unfixable advisories
Semgrep 1.168.0 pins pyjwt~=2.13.0, which dependency-review flags
(GHSA-ffc3-869f-jxw9 and 14 more). Semgrep 1.182.1 requires
pyjwt>=2.15.0; the lock file now has pyjwt 2.15.1, mcp 1.29.0 and
click 8.4.2.

Semgrep 1.182.1 still pins mcp==1.29.0 (GHSA-84m7-p3x7-pcfv) and
opentelemetry-api~=1.37.0 (GHSA-xcq7-p3pf-p88h). Neither code path is
used by `semgrep scan` in CI, so dependency-review allows both until
Semgrep lifts its pins.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-23 17:14:25 +02:00
Niels Lohmann d1235cecc9 Pin CI pip installs by hash and update KaTeX/DOMPurify
The pip installs in check_amalgamation.yml, ubuntu.yml (Meson) and
semgrep.yml now use --require-hashes with requirements files compiled by
pip-compile --generate-hashes (Python 3.14, as on ubuntu-26.04). The
astyle and generate_natvis requirements move to requirements.in, and
Meson and Semgrep get theirs in .github/requirements, which Dependabot
now watches. check_amalgamation.yml installs the natvis requirements
from the PR tree, as it already does for astyle.

The Mermaid checker overrides KaTeX to 0.18.11 (GHSA-238p-pmpm-9mq7;
Mermaid 11 still requires ^0.16.47) and updates DOMPurify to 3.4.17
(GHSA-cg2g-xh64-v4q7, GHSA-mrv2-3pqr-j5jr, GHSA-c6gr-qvv4-5v3f).

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-23 07:20:44 +02:00
675 changed files with 11780 additions and 18453 deletions

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+7 -36
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@@ -1,33 +1,3 @@
# Style or vendor rule sets that do not fit a header-only library:
# altera-*, fuchsia-*, llvmlibc-*, android-cloexec-fopen, boost-use-ranges, llvm-header-guard,
# llvm-include-order, llvm-prefer-static-over-anonymous-namespace, llvm-use-ranges,
# misc-use-anonymous-namespace, google-runtime-float, google-runtime-int, hicpp-signed-bitwise,
# bugprone-signed-bitwise, hicpp-explicit-conversions, google-explicit-constructor,
# cppcoreguidelines-explicit-constructor, misc-explicit-constructor (implicit conversions are the
# API), readability-trailing-comma,
# hicpp-avoid-goto / cppcoreguidelines-avoid-goto, hicpp-no-array-decay,
# hicpp-uppercase-literal-suffix, readability-uppercase-literal-suffix, modernize-use-trailing-return-type.
# Constructs the library needs on purpose (the library supports C++11 and legacy compilers):
# cppcoreguidelines-macro-usage, cppcoreguidelines-avoid-do-while (macros),
# cppcoreguidelines-pro-bounds-*, cppcoreguidelines-pro-type-reinterpret-cast,
# cppcoreguidelines-pro-type-union-access (parsers, serializers, basic_json's value union),
# cppcoreguidelines-avoid-const-or-ref-data-members, cppcoreguidelines-rvalue-reference-param-not-moved,
# cppcoreguidelines-avoid-non-const-global-variables, misc-non-private-member-variables-in-classes,
# misc-no-recursion (value walks are recursive, bounded by detail::recursion_depth_limit()),
# modernize-type-traits, modernize-use-constraints, modernize-use-ranges, modernize-use-std-numbers,
# modernize-use-designated-initializers, modernize-use-nodiscard, modernize-concat-nested-namespaces,
# readability-redundant-typename, readability-redundant-parentheses,
# readability-redundant-access-specifiers, readability-simplify-boolean-expr,
# readability-use-concise-preprocessor-directives, modernize-use-string-view,
# modernize-use-integer-sign-comparison (needs std::cmp_less; the flagged
# static_cast<std::size_t>(end - pos) < n comparisons are deliberate)
# (all need a newer standard or compiler than C++11, or would change macro-generated or
# deliberately explicit code).
# Too noisy to be useful (numeric parsing/formatting code, doctest, tests):
# bugprone-easily-swappable-parameters, cppcoreguidelines-avoid-magic-numbers, readability-magic-numbers,
# readability-identifier-length, readability-function-cognitive-complexity, performance-enum-size,
# concurrency-mt-unsafe, misc-confusable-identifiers, misc-include-cleaner (run on its own for
# the consumer headers in cmake/ci.cmake).
# portability-avoid-pragma-once: kept disabled on purpose. #pragma once is accepted
# by every supported compiler, and tools/amalgamate/amalgamate.py strips it from
# single_include, so there is nothing left to fix here.
@@ -40,14 +10,14 @@ Checks: '*,
-android-cloexec-fopen,
-boost-use-ranges,
-bugprone-easily-swappable-parameters,
-bugprone-signed-bitwise,
-cert-err58-cpp,
-clang-analyzer-webkit.NoUncountedMemberChecker,
-concurrency-mt-unsafe,
-cppcoreguidelines-avoid-const-or-ref-data-members,
-cppcoreguidelines-avoid-do-while,
-cppcoreguidelines-avoid-goto,
-cppcoreguidelines-avoid-magic-numbers,
-cppcoreguidelines-avoid-non-const-global-variables,
-cppcoreguidelines-explicit-constructor,
-cppcoreguidelines-macro-usage,
-cppcoreguidelines-pro-bounds-avoid-unchecked-container-access,
-cppcoreguidelines-pro-bounds-array-to-pointer-decay,
@@ -56,15 +26,19 @@ Checks: '*,
-cppcoreguidelines-pro-type-reinterpret-cast,
-cppcoreguidelines-pro-type-union-access,
-cppcoreguidelines-rvalue-reference-param-not-moved,
-cppcoreguidelines-virtual-class-destructor,
-fuchsia-default-arguments-calls,
-fuchsia-default-arguments-declarations,
-fuchsia-overloaded-operator,
-google-explicit-constructor,
-google-readability-function-size,
-google-runtime-float,
-google-runtime-int,
-hicpp-avoid-goto,
-hicpp-explicit-conversions,
-hicpp-function-size,
-hicpp-no-array-decay,
-hicpp-no-assembler,
-hicpp-signed-bitwise,
-hicpp-uppercase-literal-suffix,
-llvm-header-guard,
@@ -74,7 +48,6 @@ Checks: '*,
-llvmlibc-*,
-misc-use-anonymous-namespace,
-misc-confusable-identifiers,
-misc-explicit-constructor,
-misc-include-cleaner,
-misc-no-recursion,
-misc-non-private-member-variables-in-classes,
@@ -82,22 +55,20 @@ Checks: '*,
-modernize-type-traits,
-modernize-use-constraints,
-modernize-use-designated-initializers,
-modernize-use-integer-sign-comparison,
-modernize-use-nodiscard,
-modernize-use-ranges,
-modernize-use-string-view,
-modernize-use-std-numbers,
-modernize-use-trailing-return-type,
-performance-enum-size,
-portability-avoid-pragma-once,
-readability-function-cognitive-complexity,
-readability-function-size,
-readability-identifier-length,
-readability-magic-numbers,
-readability-redundant-access-specifiers,
-readability-redundant-parentheses,
-readability-redundant-typename,
-readability-simplify-boolean-expr,
-readability-trailing-comma,
-readability-uppercase-literal-suffix,
-readability-use-concise-preprocessor-directives'
+8 -1
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@@ -29,6 +29,13 @@ updates:
- dependency-name: mermaid
update-types: ["version-update:semver-major"]
- package-ecosystem: pip
directory: /.github/requirements
schedule:
interval: daily
cooldown:
default-days: 7
- package-ecosystem: pip
directory: /tools/astyle
schedule:
@@ -36,7 +43,7 @@ updates:
cooldown:
default-days: 7
ignore:
# astyle is deliberately pinned (see tools/astyle/requirements.txt): newer versions
# astyle is deliberately pinned (see tools/astyle/requirements.in): newer versions
# reformat the code, and the pinned version defines the formatting CI enforces
- dependency-name: astyle
+1
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@@ -0,0 +1 @@
meson==1.12.1
+10
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@@ -0,0 +1,10 @@
#
# This file is autogenerated by pip-compile with Python 3.14
# by the following command:
#
# pip-compile --generate-hashes --no-emit-index-url --output-file=.github/requirements/meson.txt --strip-extras .github/requirements/meson.in
#
meson==1.12.1 \
--hash=sha256:930bc7542cbd9f57009e182fd014eba48cf1a0180a7b9006d2d32d8f168d8b02 \
--hash=sha256:ab0a6ca09f8ef70c564c8241fb5a23957886a0b53fb58412b5e07eaf07dba743
# via -r .github/requirements/meson.in
+1
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@@ -0,0 +1 @@
semgrep==1.182.1
File diff suppressed because it is too large. Load diff
+5 -5
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@@ -67,10 +67,10 @@ jobs:
- name: Install astyle
run: |
python3 -mvenv venv
venv/bin/pip3 install -r $MAIN_DIR/tools/astyle/requirements.txt
venv/bin/pip3 install --require-hashes -r $MAIN_DIR/tools/astyle/requirements.txt
- name: Install generate_natvis dependencies
run: pip3 install -r $NATVIS_TOOL_DIR/requirements.txt
run: pip3 install --require-hashes -r $MAIN_DIR/tools/generate_natvis/requirements.txt
- name: Regenerate the tools/macro_builder tables in macro_scope.hpp
run: |
@@ -163,9 +163,9 @@ jobs:
python3 $GENERATOR --list-tags
TAG_COUNT=$(python3 $GENERATOR --list-tags | wc -l)
python3 $GENERATOR --abi-tags diag,_dp,_ns --abi-tags _diag --output $RUNNER_TEMP/abi_tags.natvis
grep -q '<!-- Namespace nlohmann::json_abi_diag_dp_ns -->' $RUNNER_TEMP/abi_tags.natvis
grep -q '<!-- Namespace nlohmann::json_abi_diag_dp_ns_v[0-9_]* -->' $RUNNER_TEMP/abi_tags.natvis
python3 $GENERATOR --abi-tags diag,_dp,_vns --abi-tags _diag --output $RUNNER_TEMP/abi_tags.natvis
grep -q '<!-- Namespace nlohmann::json_abi_diag_dp_vns -->' $RUNNER_TEMP/abi_tags.natvis
grep -q '<!-- Namespace nlohmann::json_abi_diag_dp_vns_v[0-9_]* -->' $RUNNER_TEMP/abi_tags.natvis
test $(grep -c '<!-- Namespace ' $RUNNER_TEMP/abi_tags.natvis) -eq $(( $(grep -c '<!-- Namespace ' nlohmann_json.natvis) + 2 ))
python3 $GENERATOR --all --output $RUNNER_TEMP/all.natvis
+9
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@@ -31,3 +31,12 @@ jobs:
persist-credentials: false
- name: 'Dependency Review'
uses: actions/dependency-review-action@a1d282b36b6f3519aa1f3fc636f609c47dddb294 # v5.0.0
with:
# Semgrep pins mcp==1.29.0 and opentelemetry-api~=1.37.0 exactly
# (.github/requirements/semgrep.txt), so these cannot be upgraded
# until Semgrep lifts its pins. They do not apply to our use: CI
# only runs `semgrep scan` on the checkout and never starts the MCP
# server (GHSA-84m7-p3x7-pcfv, StreamableHTTP sessions) or parses
# incoming trace context (GHSA-xcq7-p3pf-p88h, tracestate parsing).
# Remove the entries once a Semgrep release allows the fixed versions.
allow-ghsas: GHSA-84m7-p3x7-pcfv, GHSA-xcq7-p3pf-p88h
+1 -2
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@@ -43,8 +43,7 @@ jobs:
- name: flawfinder_scan
uses: david-a-wheeler/flawfinder@c4216b74cf2639ffa98503768bd6e4299b5440c9 # v2.0.20
with:
# single_include/ is generated from include/ and would report every finding twice
arguments: "--sarif --exclude '*/single_include/*' ./"
arguments: '--sarif ./'
output: 'flawfinder_results.sarif'
- name: Upload analysis results to GitHub Security tab
+1 -1
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@@ -53,7 +53,7 @@ jobs:
# SEMGREP_APP_TOKEN is still passed through so registry auth works if a
# token is ever added.
- name: Install Semgrep
run: python3 -m pip install --user semgrep==1.168.0
run: python3 -m pip install --user --require-hashes -r .github/requirements/semgrep.txt
# `semgrep scan --sarif` always exits 0 even with findings; continue-on-error
# is a safety net so the SARIF upload still runs if the scan itself errors.
+1 -1
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@@ -42,7 +42,7 @@ jobs:
- name: Check that Meson and pkg-config offer the CMake options
run: make check_build_options
- name: Install Meson
run: pip install meson
run: pip install --require-hashes -r .github/requirements/meson.txt
- name: Install with Meson
run: |
meson setup build-meson --prefix=${{ github.workspace }}/install
-1
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@@ -90,7 +90,6 @@ cc_library(
"include/nlohmann/detail/view/simd.hpp",
"include/nlohmann/detail/view/string_ref.hpp",
"include/nlohmann/detail/view/value.hpp",
"include/nlohmann/detail/view/view_mode.hpp",
"include/nlohmann/json.hpp",
"include/nlohmann/json_fwd.hpp",
"include/nlohmann/json_literals.hpp",
+1 -1
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@@ -309,7 +309,7 @@ The "Check amalgamation" workflow fails if the file is out of date.
The file covers the namespace variants with up to two ABI tags. A Natvis file for other configurations can be
generated with the `--abi-tags` or `--all` options, for example
`make natvis NATVIS_ARGS="--abi-tags _diag,_dp,_ns --output my_nlohmann_json.natvis"`; see
`make natvis NATVIS_ARGS="--abi-tags _diag,_dp,_vns --output my_nlohmann_json.natvis"`; see
[`tools/generate_natvis`](tools/generate_natvis/README.md). With MSVC, CMake adds the file to the `nlohmann_json`
target and installs it.
+1 -1
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@@ -120,7 +120,7 @@ $(AMALGAMATED_VIEW_FILE): $(SRCS)
tools/amalgamate/amalgamate.py -c tools/amalgamate/config_json_view.json -s . --verbose=yes
NATVIS_VENV=tools/generate_natvis/venv
# extra options for generate_natvis.py, e.g. NATVIS_ARGS="--abi-tags _diag,_dp,_ns --output my.natvis"
# extra options for generate_natvis.py, e.g. NATVIS_ARGS="--abi-tags _diag,_dp,_vns --output my.natvis"
NATVIS_ARGS=
# regenerate nlohmann_json.natvis from the ABI tags and version in include/nlohmann/detail/abi_macros.hpp
+4 -4
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@@ -151,7 +151,7 @@ The `json` class provides an API for manipulating a JSON value. To create a `jso
```cpp
#include <fstream>
#include <nlohmann/json.hpp>
using nlohmann::json;
using json = nlohmann::json;
// ...
@@ -164,7 +164,7 @@ If using modules (enabled with `NLOHMANN_JSON_BUILD_MODULES`), this example beco
import std;
import nlohmann.json;
using nlohmann::json;
using json = nlohmann::json;
// ...
@@ -842,7 +842,7 @@ assert(p == p2);
To make this work with one of your types, you only need to provide two functions:
```cpp
using nlohmann::json;
using json = nlohmann::json;
namespace ns {
void to_json(json& j, const person& p) {
@@ -1257,7 +1257,7 @@ See the page [quality assurance](https://json.nlohmann.me/community/quality_assu
#include <nlohmann/json.hpp>
// for convenience
using nlohmann::json;
using json = nlohmann::json;
```
to the files you want to process JSON and set the necessary switches to enable C++11 (e.g., `-std=c++11` for GCC and Clang).
+1 -2
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@@ -341,14 +341,13 @@ def download(url, docs) -> str:
raise ValueError(f'not an http(s) URL: {url}')
req = urllib.request.Request(u.geturl(), headers={'User-Agent': USER_AGENT})
# (the scheme is checked above)
# nosemgrep: python.lang.security.audit.dynamic-urllib-use-detected.dynamic-urllib-use-detected
with urllib.request.urlopen(req, timeout=20) as r: # nosec B310
data = r.read()
ctype = r.headers.get_content_type()
path = urllib.parse.unquote(u.path).lstrip('/')
ext = os.path.splitext(path)[1]
if u.query or not ext or path.endswith('/'):
digest = hashlib.sha256(url.encode()).hexdigest()[:12]
digest = hashlib.sha1(url.encode(), usedforsecurity=False).hexdigest()[:12]
path = os.path.join(os.path.dirname(path), digest + CONTENT_TYPE_EXT.get(ctype, ext or '.bin'))
rel = os.path.normpath(os.path.join('assets', 'external', u.hostname, path))
out = os.path.join(docs, rel)
@@ -30,14 +30,6 @@ struct adl_serializer {
- [**from_json**](from_json.md) - convert a JSON value to any value type
- [**to_json**](to_json.md) - convert any value type to a JSON value
## See also
- [Arbitrary type conversions](../../features/arbitrary_types.md) - how to make your types convertible
- [**get**](../basic_json/get.md) / [**get_to**](../basic_json/get_to.md) - convert a JSON value to a C++ type
- [**basic_json**](../basic_json/basic_json.md) - construct a JSON value from a C++ value
- [**NLOHMANN_DEFINE_TYPE_INTRUSIVE**](../macros/nlohmann_define_type_intrusive.md) - generate the conversion functions for a type
- [Specializing enum conversion](../../features/enum_conversion.md)
## Version history
- Added in version 2.1.0.
+1 -25
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@@ -23,9 +23,6 @@ Checks whether the input is valid JSON.
respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
the iterator type with `operator!=`.
Ill-formed UTF-16 and UTF-32 sequences are rejected: a lone surrogate, a high surrogate that is not followed by its
low surrogate, and a code point above `U+10FFFF` all make this function return `false`.
Unlike the [`parse()`](parse.md) function, this function neither throws an exception in case of invalid JSON input
(i.e., a parse error) nor creates diagnostic information.
@@ -38,12 +35,9 @@ Unlike the [`parse()`](parse.md) function, this function neither throws an excep
- a `#!c FILE` pointer (throws if null)
- a C-style array of characters
- a pointer to a null-terminated string of single byte characters (throws if null)
- a `std::string` or a `std::string_view` (C++17)
- a `std::string`
- a container `obj` for which `begin(obj)` and `end(obj)` produce a valid pair of iterators
(as found via ADL or member functions, with semantics compatible to `std::begin` and `std::end`)
- wide characters (`wchar_t`, `char16_t`, `char32_t`), which are converted to UTF-8: a wide string object
(`std::wstring`, `std::u16string`, `std::u32string`) or an array (e.g. a wide string literal); a pointer to a
null-terminated wide string (e.g. `std::u16string::c_str()`) is not supported
`IteratorType`
: a compatible iterator type, for instance.
@@ -131,21 +125,6 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/accept__iterator_pair.output"
```
??? example "Example: (3) reading from UTF-16 strings"
The encoding is deduced from the character type of the input. String literals like `u"..."`, `U"..."`, and
`L"..."` work as well.
```cpp
--8<-- "examples/accept__wide_string.cpp"
```
Output:
```json
--8<-- "examples/accept__wide_string.output"
```
## See also
- [parse](parse.md) - deserialize from a compatible input
@@ -172,9 +151,6 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
([`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)).
- Ill-formed UTF-16 and UTF-32 input (a lone surrogate, a high surrogate that is not followed by its low surrogate, or
a code point above `U+10FFFF`) is rejected in version 3.13.0; before that, some such sequences were accepted or
ended the input silently.
!!! warning "Deprecation"
+4 -4
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@@ -90,8 +90,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
1. Constant.
2. Logarithmic in the size of the container.
3. Logarithmic in the size of the container.
4. Linear in the number of reference tokens of `ptr`; for each of them, logarithmic in the size of the object, or
constant for an array.
4. Logarithmic in the size of the container.
## Notes
@@ -240,8 +239,9 @@ Strong exception safety: if an exception occurs, the original value stays intact
1. Added in version 1.0.0.
2. Added in version 1.0.0.
3. Added in version 3.11.0. Support for keys convertible to `std::string_view` added in version 3.13.0, consistently
across the lookup functions.
3. Added in version 3.11.0. Fixed in version 3.13.0 to consistently accept `std::string_view`-convertible keys, as
already supported by [`operator[]`](operator[].md), [`value`](value.md), [`find`](find.md), and other lookup
functions.
4. Added in version 2.0.0. Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) instead of
[`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) for a one-character array index that is not
a digit (e.g., `/x`) in version 3.13.0, as it already did for longer ones.
+1 -1
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@@ -63,4 +63,4 @@ Constant.
## Version history
- Added in version 1.0.0.
- Binary values are supported since version 3.8.0.
- Adjusted code to return reference to binary values in version 3.8.0.
@@ -482,15 +482,15 @@ basic_json(basic_json&& other) noexcept;
## Version history
1. Added in version 1.0.0.
2. Added in version 1.0.0.
3. Added in version 2.1.0.
4. Added in version 3.1.2. Explicit for different string types if `JSON_USE_IMPLICIT_CONVERSIONS` is `0` since
1. Since version 1.0.0.
2. Since version 1.0.0.
3. Since version 2.1.0.
4. Since version 3.2.0. Explicit for different string types if `JSON_USE_IMPLICIT_CONVERSIONS` is `0` since
version 3.13.0.
5. Added in version 1.0.0.
6. Added in version 1.0.0.
7. Added in version 1.0.0. Fixed in version 3.13.0 to also check the iterator range for binary values; before, a range
5. Since version 1.0.0.
6. Since version 1.0.0.
7. Since version 1.0.0. Fixed in version 3.13.0 to also check the iterator range for binary values; before, a range
that did not cover the whole value (such as `(end(), end())`) was accepted and the whole binary value was copied,
unlike the other primitive types.
8. Added in version 1.0.0.
9. Added in version 1.0.0.
8. Since version 1.0.0.
9. Since version 1.0.0.
+2 -3
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@@ -90,9 +90,8 @@ type `#!cpp binary_t*` must be dereferenced.
- MessagePack
- If a subtype is given and the binary array contains exactly 1, 2, 4, 8, or 16 elements, the fixext family (fixext1,
fixext2, fixext4, fixext8, fixext16) is used. For other sizes, the ext family (ext8, ext16, ext32) is used. The
subtype is then written as the signed 8-bit ext type: subtypes 128 to 255 map to the negative (reserved) ext
types, and on reading the ext type is exposed as an unsigned subtype from 0 to 255.
fixext2, fixext4, fixext8) is used. For other sizes, the ext family (ext8, ext16, ext32) is used. The subtype is
then added as a signed 8-bit integer.
- If no subtype is given, the bin family (bin8, bin16, bin32) is used.
- BSON
@@ -1,48 +0,0 @@
# <small>nlohmann::basic_json::</small>bjdata_version_t
```cpp
enum class bjdata_version_t
{
draft2,
draft3
};
```
This enumeration is used in [`to_bjdata`](to_bjdata.md) to choose the version of the BJData specification to write:
draft2
: BJData Draft 2 (the default). Binary values are written as arrays of `U` integers, and ND-arrays with
`"_ArrayType_": "byte"` are written as regular objects, since the `B` marker is not part of Draft 2.
draft3
: BJData Draft 3. Binary values are written as `B` elements: as an optimized binary array (`[$B#`) if both `use_size`
and `use_type` are set, and as an array of `B`-prefixed elements otherwise. ND-arrays with
`"_ArrayType_": "byte"` are written as packed arrays (`[$B#[...]`).
Only the writer is affected by the version. [`from_bjdata`](from_bjdata.md) reads the markers of both drafts.
## Examples
??? example
The example below shows how the different values of the `bjdata_version_t` influence the serialization of a binary
value with [`to_bjdata`](to_bjdata.md).
```cpp
--8<-- "examples/bjdata_version_t.cpp"
```
Output:
```json
--8<-- "examples/bjdata_version_t.output"
```
## See also
- [to_bjdata](to_bjdata.md) serializes a JSON value to BJData
- [BJData](../../features/binary_formats/bjdata.md) - the article on the BJData format
## Version history
- Added in version 3.12.0.
@@ -15,13 +15,11 @@ error
: report a parse error in case of a tag (the `from_cbor` overloads throw a `parse_error` exception by default)
ignore
: ignore tags (also in front of a text string map key)
: ignore tags
store
: store tagged byte strings (for bytes 0xd8..0xdb) as binary values with the tag as subtype; other tagged values are
read as if the tag were ignored. If several tags precede a byte string, only the tag directly in front of it is
stored, and only when it has the form 0xd8..0xdb (a tag 0..23 written as 0xc0..0xd7 is skipped). Tags in front of a
text string map key are skipped.
read as if the tag were ignored. If several tags precede a byte string, only the innermost one is stored.
## Examples
+5 -11
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@@ -61,18 +61,11 @@ Strong exception safety: if an exception occurs, the original value stays intact
## Complexity
1. Logarithmic in the size of the JSON object.
2. Logarithmic in the size of the JSON object.
3. At most one lookup per reference token of `ptr`, each logarithmic in the size of the container at that level:
O(*n* log *m*) for *n* reference tokens and containers of size at most *m*.
4. Deleted; a call with an integral argument does not compile.
Logarithmic in the size of the JSON object.
## Notes
- Overloads (1) and (2) always return `#!cpp false` when executed on a JSON type that is not an object. Overload (3)
also works on arrays and on primitive values: the empty JSON pointer resolves in every JSON value (so
`#!cpp json(1).contains(""_json_pointer)` returns `#!cpp true`), and `#!cpp json({1, 2}).contains("/1"_json_pointer)`
returns `#!cpp true`.
- This method always returns `#!cpp false` when executed on a JSON type that is not an object.
- This method can be executed on any JSON value type.
- Calling this function with an integer argument (for example, `#!cpp contains(0)`) does not compile: such an argument
would otherwise implicitly convert to a null `#!cpp const char*` and, from there, cause undefined behavior when
@@ -148,8 +141,9 @@ Strong exception safety: if an exception occurs, the original value stays intact
## Version history
1. Added in version 3.11.0.
2. Added in version 3.6.0. Extended template `KeyType` to support comparable types in version 3.11.0. Support for keys
convertible to `std::string_view` added in version 3.13.0, consistently across the lookup functions.
2. Added in version 3.6.0. Extended template `KeyType` to support comparable types in version 3.11.0. Fixed in
version 3.13.0 to consistently accept `std::string_view`-convertible keys, as already supported by
[`operator[]`](operator[].md), [`at`](at.md), [`value`](value.md), and other lookup functions.
3. Added in version 3.7.0.
4. Deleted overloads for integral key types added in version 3.13.0 to reject such calls at compile time instead of
causing undefined behavior at runtime.
+3 -2
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@@ -92,7 +92,8 @@ Logarithmic in the size of the JSON object.
## Version history
1. Added in version 3.11.0.
2. Added in version 1.0.0. Changed to support comparable key types in version 3.11.0. Support for keys convertible to
`std::string_view` added in version 3.13.0, consistently across the lookup functions.
2. Added in version 1.0.0. Changed parameter `key` type to `KeyType&&` in version 3.11.0. Fixed in version 3.13.0 to
consistently accept `std::string_view`-convertible keys, as already supported by [`operator[]`](operator[].md),
[`at`](at.md), [`value`](value.md), and other lookup functions.
3. Deleted overload for integral key types added in version 3.13.0 to reject such calls at compile time instead of
causing undefined behavior at runtime.
+4 -41
View File
@@ -2,27 +2,17 @@
```cpp
static basic_json diff(const basic_json& source,
const basic_json& target,
const string_t& path = "");
const basic_json& target);
```
Creates a [JSON Patch](http://jsonpatch.com) so that value `source` can be changed into the value `target` by calling
[`patch`](patch.md) function.
For two JSON values `source` and `target`, the following code yields `#!cpp true`:
For two JSON values `source` and `target`, the following code always yields `#!cpp true`:
```cpp
source.patch(diff(source, target)) == target;
```
The equality holds up to [`operator==`](operator_eq.md), so it has the following exceptions:
- A value that is not equal to itself cannot round-trip. This applies to `NaN` (also nested in an array or object) and
to [discarded](is_discarded.md) values: `diff` emits a `replace` operation for them. A `NaN` in the patch is
serialized as `#!json null`, so a patch that was dumped and parsed again would set `#!json null`.
- Numbers that compare equal produce no operation, even if their types or signs differ: `diff(1, 1.0)`,
`diff(1u, 1)` (unsigned and signed integer) and `diff(0.0, -0.0)` all return `#!json []`. The patched value is then
the `source` and keeps its number type.
## Parameters
`source` (in)
@@ -31,12 +21,6 @@ The equality holds up to [`operator==`](operator_eq.md), so it has the following
`target` (in)
: JSON value to compare against
`path` (in)
: a prefix that is put verbatim in front of the `path` member of every operation (default: `""`, which addresses the
root of the value). The prefix is neither escaped nor validated: `#!cpp diff(1, 2, "abc")` yields an operation with
the `path` `abc`, which is not a valid JSON Pointer. Use it with a valid JSON Pointer such as `/root` and escape
`~` and `/` in its reference tokens (see [JSON Pointer](../../features/json_pointer.md)).
## Return value
a JSON patch to convert the `source` to `target`
@@ -47,32 +31,11 @@ Strong guarantee: `source` and `target` are never modified.
## Complexity
Linear in the total number of values (including nested ones) in `source` and `target`, times the cost of a key-based
object operation (looking up a key in an object): logarithmic for [`json`](../json.md), and linear for
[`ordered_json`](../ordered_json.md) (see [`ordered_map` complexity](../ordered_map.md#complexity)). For
`ordered_json`, diffing two objects with `n` and `m` members therefore takes O((n+m)²) when their keys do not line up
(e.g., a key was added or the keys are in a different order). The size of the patch is proportional to the number of
operations times the length of their paths, so a small change deep inside a value yields a long `path`.
Linear in the lengths of `source` and `target`.
## Notes
- Currently, only `remove`, `add`, and `replace` operations are generated.
- The patch is correct, but not guaranteed to be minimal. For instance, `diff([1,2,3], [0,1,2,3])` yields three
`replace` operations and one `add` operation instead of a single insertion.
- Differences between two arrays are reported index by index. Elements that were added at the end of the array are added
with `add` operations on the path `/-` (appended in order), and elements that were removed are removed with `remove`
operations from the highest index down to the lowest, so that the remaining indices stay valid.
- For objects, the operations for the members of `source` come first (`replace`, `remove`, or the operations for nested
values, in the iteration order of `source`), followed by `add` operations for the members that only `target` has.
- For [`ordered_json`](../ordered_json.md), objects with the same keys in a different order are different. As a patch
cannot reorder members, `diff` removes all keys of the `source` object and adds them again in the order of the
`target`.
- If `source` and `target` differ as a whole (e.g., different types), the patch consists of a single `replace`
operation for the root of the value, i.e., with the `path` `""` (or the given `path` prefix).
- The `value` members of the patch hold copies of values of `target`. A [binary](../../features/binary_values.md) value
has no JSON representation: when a patch that contains one is serialized, it becomes an object such as
`#!json {"bytes":[1,3],"subtype":null}`, so a parsed patch no longer holds a binary value (and would set that object
instead).
Currently, only `remove`, `add`, and `replace` operations are generated.
## Examples
+1 -1
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@@ -69,6 +69,6 @@ Logarithmic in the size of the container, O(log(`size()`)).
## Version history
- Added in version 2.0.8.
- Since version 2.0.8.
- Fixed in version 3.13.0: for [`ordered_json`](../ordered_json.md), the value could previously only be passed as an
rvalue; it can now also be passed as an lvalue or a `#!cpp const` lvalue, matching the behavior of `json`.
@@ -67,5 +67,5 @@ Amortized constant.
## Version history
- Added in version 2.0.8.
- Since version 2.0.8.
- Returns reference since 3.7.0.
+3 -2
View File
@@ -213,6 +213,7 @@ Strong exception safety: if an exception occurs, the original value stays intact
1. Added in version 1.0.0. Added support for binary types in version 3.8.0.
2. Added in version 1.0.0. Added support for binary types in version 3.8.0.
3. Added in version 1.0.0.
4. Added in version 3.11.0. Support for keys convertible to `std::string_view` added in version 3.13.0, consistently
across the lookup functions.
4. Added in version 3.11.0. Fixed in version 3.13.0 to consistently accept `std::string_view`-convertible keys, as
already supported by [`operator[]`](operator[].md), [`at`](at.md), [`value`](value.md), and other lookup
functions.
5. Added in version 1.0.0.
+1 -1
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@@ -84,4 +84,4 @@ constructor.
## Version history
- Added in version 3.0.0.
- Since version 3.0.0.
+3 -2
View File
@@ -99,7 +99,8 @@ Logarithmic in the size of the JSON object.
## Version history
1. Added in version 3.11.0.
2. Added in version 1.0.0. Changed to support comparable types in version 3.11.0. Support for keys convertible to
`std::string_view` added in version 3.13.0, consistently across the lookup functions.
2. Added in version 1.0.0. Changed to support comparable types in version 3.11.0. Fixed in version 3.13.0 to
consistently accept `std::string_view`-convertible keys, as already supported by [`operator[]`](operator[].md),
[`at`](at.md), [`value`](value.md), and other lookup functions.
3. Deleted overloads for integral key types added in version 3.13.0 to reject such calls at compile time instead of
causing undefined behavior at runtime.
@@ -82,11 +82,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs
- Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a string could not be parsed
successfully, or if a string value or object key is not valid UTF-8 and `error_handler` is `strict`
- Throws [parse_error.115](../../home/exceptions.md#jsonexceptionparse_error115) if the text of a high-precision
number (`H`) is not a valid number
- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the size of an optimized container
cannot be represented by `std::size_t` or exceeds the container's `max_size()`, or if the product of the dimensions of
an n-dimensional array overflows
or n-dimensional array cannot be represented by `std::size_t`
## Complexity
@@ -74,11 +74,6 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs, for instance
an invalid byte, a string that is not valid UTF-8, or an object key that is not a string
The UTF-8 validity of strings is always checked, independent of
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md), because the end of a BON8 string is determined from
its encoding. Duplicate object keys are accepted; the last value wins (see
[BON8](../../features/binary_formats/bon8.md)).
## Complexity
Linear in the size of the input.
+1 -2
View File
@@ -80,8 +80,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [`parse_error.110`](../../home/exceptions.md#jsonexceptionparse_error110) if the given input ends prematurely or
the end of the input was not reached when `strict` was set to true
- Throws [`parse_error.112`](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs (e.g., an
invalid string or byte array length, an invalid inner length of a binary value with subtype `0x02`, or a document size
that does not match the content; `strict` does not affect the document size checks)
invalid string or byte array length)
- Throws [`parse_error.114`](../../home/exceptions.md#jsonexceptionparse_error114) if an unsupported BSON record type is
encountered
- Throws [`parse_error.113`](../../home/exceptions.md#jsonexceptionparse_error113) if a string value or object key is
+4 -12
View File
@@ -32,10 +32,8 @@ The exact mapping and its limitations are described on a [dedicated page](../../
- an `std::istream` object
- a `FILE` pointer
- a C-style array of characters (its terminating NUL is read as trailing data: `parse_error.110` unless `strict` is
`false`)
- a pointer to a null-terminated string of single byte characters (read up to the first 0x00 byte, which is a valid
CBOR byte)
- a C-style array of characters
- a pointer to a null-terminated string of single byte characters
- a container `obj` for which `begin(obj)` and `end(obj)` produce a valid pair of iterators
(as found via ADL or member functions, with semantics compatible to `std::begin` and `std::end`)
@@ -91,14 +89,8 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if unsupported features from CBOR were
used in the given input or if the input is not valid CBOR
- Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a map key is not a string (keys of
other types are not supported, as JSON object keys are always strings), if the head of a string or byte string is
malformed (including a chunk of the wrong type or an indefinite-length string nested inside an indefinite-length
string), or if a string value or object key (or one chunk of an indefinite-length string) is not valid UTF-8 and
`error_handler` is `strict`
- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if an array or map announces
a length that `std::size_t` cannot hold, or that equals `std::size_t(-1)` (for example `9B FF FF FF FF FF FF FF FF`)
- Throws [out_of_range.406](../../home/exceptions.md#jsonexceptionout_of_range406) if a floating-point number does not
fit into `number_float_t`
other types are not supported, as JSON object keys are always strings), or if a string value or object key is not
valid UTF-8 and `error_handler` is `strict`
## Complexity
+4 -11
View File
@@ -79,18 +79,11 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [parse_error.110](../../home/exceptions.md#jsonexceptionparse_error110) if the given input ends prematurely or
the end of the file was not reached when `strict` was set to true
- Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if an invalid type marker is read
(including a type marker after `$` of an optimized container, even if its count is 0), or if `$` is not followed by `#`
- Throws [parse_error.112](../../home/exceptions.md#jsonexceptionparse_error112) if a parse error occurs
- Throws [parse_error.113](../../home/exceptions.md#jsonexceptionparse_error113) if a string could not be parsed
successfully (negative or non-integer length, `C` followed by a byte above 0x7F), if the count of an optimized
container is negative, or if a string value or object key is not valid UTF-8 and `error_handler` is `strict`
- Throws [parse_error.115](../../home/exceptions.md#jsonexceptionparse_error115) if the text of a high-precision number
(`H`) is not a valid JSON number
- Throws [out_of_range.406](../../home/exceptions.md#jsonexceptionout_of_range406) if a high-precision number, or a
float64 when `number_float_t` is `float`, does not fit into `number_float_t`
- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the count of an optimized
container exceeds the capacity of the container (or of `std::size_t`), or if an optimized array of `Z`, `T`, or `F` has
more than 1,048,576 elements
successfully, or if a string value or object key is not valid UTF-8 and `error_handler` is `strict`
- Throws [out_of_range.408](../../home/exceptions.md#jsonexceptionout_of_range408) if the size of an optimized container
or n-dimensional array cannot be represented by `std::size_t`
## Complexity
+1 -1
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@@ -57,4 +57,4 @@ Constant.
## Version history
- Added in version 1.0.0.
- Binary values are supported since version 3.8.0.
- Adjusted code to return reference to binary values in version 3.8.0.
+3 -3
View File
@@ -188,6 +188,6 @@ overload (3).
## Version history
1. Added in version 2.1.0.
2. Added in version 2.1.0. Extended to work with other specializations of `basic_json` in version 3.1.2.
3. Added in version 1.0.0.
1. Since version 2.1.0.
2. Since version 2.1.0. Extended to work with other specializations of `basic_json` in version 3.2.0.
3. Since version 1.0.0.
+1 -1
View File
@@ -45,7 +45,7 @@ Constant.
#include <iostream>
#include <nlohmann/json.hpp>
using nlohmann::json;
using json = nlohmann::json;
int main()
{
+1 -1
View File
@@ -76,5 +76,5 @@ Depends on the `json_serializer<ValueType>::from_json()` implementation.
## Version history
- Added in version 3.3.0.
- Since version 3.3.0.
- Added a `static_assert` with a clear message for `const` arguments in version 3.13.0.
-20
View File
@@ -44,22 +44,6 @@ are collected in [Template Parameter Requirements](../../features/types/template
- [**json**](../json.md) - default specialization
- [**ordered_json**](../ordered_json.md) - a specialization that maintains the insertion order of object keys
## Documents and views
Besides `basic_json`, the library offers a second way to hold a parsed JSON text: a
[`basic_json_document`](../basic_json_document/index.md), which owns or borrows the text and holds a flat index of the
values in it, and a [`basic_json_view`](../basic_json_view/index.md), a read-only handle to one value of such a document.
Both are defined in the header `<nlohmann/json_view.hpp>`; see
[Zero-copy JSON views](../../features/json_view.md) for the concept and the trade-offs.
- [**json_document**](../json_document.md) / [**ordered_json_document**](../ordered_json_document.md) - read-only
documents of the `basic_json` specialization they belong to
- [**json_editable_document**](../json_editable_document.md) /
[**ordered_json_editable_document**](../ordered_json_editable_document.md) - documents that can be modified in place
- [**json_view**](../json_view.md) / [**ordered_json_view**](../ordered_json_view.md) - views of a document
- [**json_editable_view**](../json_editable_view.md) /
[**ordered_json_editable_view**](../ordered_json_editable_view.md) - views of an editable document
## Iterator invalidation
All operations that add values to an **array** ([`push_back`](push_back.md) , [`operator+=`](operator+=.md),
@@ -121,7 +105,6 @@ The class satisfies the following concept requirements:
- [**json_pointer**](../json_pointer/index.md) - JSON Pointer implementation
- [**json_serializer**](json_serializer.md) - type of the serializer to for conversions from/to JSON
- [**error_handler_t**](error_handler_t.md) - type to choose behavior on decoding errors
- [**bjdata_version_t**](bjdata_version_t.md) - type to choose the BJData version to write
- [**cbor_tag_handler_t**](cbor_tag_handler_t.md) - type to choose how to handle CBOR tags
- **initializer_list_t** - type for initializer lists of `basic_json` values
- [**input_format_t**](input_format_t.md) - type to choose the format to parse
@@ -360,9 +343,6 @@ Access to the JSON value
## See also
- [RFC 8259: The JavaScript Object Notation (JSON) Data Interchange Format](https://tools.ietf.org/html/rfc8259)
- [basic_json_document](../basic_json_document/index.md) / [basic_json_view](../basic_json_view/index.md) - parse a JSON
text into a flat index and read it through a view
- [Zero-copy JSON views](../../features/json_view.md) - when to use a document and a view instead of a `basic_json`
## Version history
@@ -75,4 +75,4 @@ classDiagram
## Version history
- Added in version 3.0.0.
- Since version 3.0.0.
+2 -2
View File
@@ -104,8 +104,8 @@ When iterating over an array, `key()` will return the index of the element as st
## Version history
- Added in version 3.1.0 as the replacement of the static function `iterator_wrapper`, which was available since
version 1.0.0 and is deprecated since version 3.1.0.
- Added `iterator_wrapper` in version 3.0.0.
- Added `items` and deprecated `iterator_wrapper` in version 3.1.0.
- Added structured binding support in version 3.5.0.
!!! warning "Deprecation"
@@ -51,4 +51,4 @@ deserializes. See [Template Parameter Requirements](../../features/types/templat
## Version history
- Added in version 2.1.0.
- Since version 2.0.0.
+5 -25
View File
@@ -39,33 +39,13 @@ Basic guarantee: if an exception is thrown during the operation, the JSON value
## Complexity
Linear in the total number of values (including nested ones) in `apply_patch`, times the cost of a key-based object
operation (looking up, adding, or erasing a member): logarithmic for [`json`](../json.md), and linear for
[`ordered_json`](../ordered_json.md) (see [`ordered_map` complexity](../ordered_map.md#complexity)). For
`ordered_json`, patching an object that has `n` members with a patch that has `m` members therefore takes O(n·m). The
cost also includes one copy of `apply_patch` (see the notes below).
Linear in the lengths of `apply_patch`.
## Notes
- `apply_patch` may be `#!cpp *this` itself or refer to a value contained in `#!cpp *this` (for example, a subobject
returned by `#!cpp (*this)[key]`); it is read as it was when `merge_patch()` was called, before any modification of
`#!cpp *this`. To make this possible, the function copies `apply_patch` before it modifies `#!cpp *this`, so the cost
includes one copy of the patch.
- A merge patch uses `#!json null` to remove a member, so it cannot set a member to `#!json null`: applying
`#!json {"a":null}` to `#!json {"a":1}` gives `#!json {}`.
- Arrays are not merged: an array in the patch replaces the target value as a whole, and a `#!json null` inside an
array is kept as an element. `#!json null` members of the target that the patch does not mention are preserved.
- A `#!json null` in the patch only removes a member; it does not prevent the creation of the enclosing objects.
Applying `#!json {"a":{"b":null}}` to `#!json {}` gives `#!json {"a":{}}` (see example 15 in Appendix A of the RFC).
- If `apply_patch` is not an object, it replaces the target as a whole. In particular, a `#!json null` patch turns the
target into `#!json null`. If `apply_patch` is an object and the target is not, the target is first replaced by an
empty object, so applying `#!json {}` to `#!json 1` gives `#!json {}`.
- A merge patch cannot express every change; for example, it cannot reorder array elements or remove a specific array
element. Use [JSON Patch](../../features/json_patch.md) ([RFC 6902](https://tools.ietf.org/html/rfc6902)) for that.
[`merge_diff`](merge_diff.md) has a matching limitation, see its notes.
- A [discarded](is_discarded.md) value is treated like any other non-object value: a discarded
`apply_patch` turns the target into a discarded value, and an object patch replaces a discarded target by an object
as described above.
`apply_patch` may be `#!cpp *this` itself or refer to a value contained in `#!cpp *this` (for example, a subobject
returned by `#!cpp (*this)[key]`); it is read as it was when `merge_patch()` was called, before any modification of
`#!cpp *this`.
## Examples
@@ -91,6 +71,6 @@ cost also includes one copy of `apply_patch` (see the notes below).
## Version history
- Added in version 3.1.0.
- Added in version 3.0.0.
- Fixed use of freed or relocated memory when `apply_patch` is `#!cpp *this` or refers to a value contained in
`#!cpp *this`, in version 3.13.0.
@@ -128,6 +128,6 @@ interpreted as `object_t::value_type` or `std::initializer_list<basic_json>`, se
## Version history
1. Added in version 1.0.0.
2. Added in version 1.0.0.
3. Added in version 2.0.0.
1. Since version 1.0.0.
2. Since version 1.0.0.
3. Since version 2.0.0.
+10 -31
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@@ -92,20 +92,12 @@ Strong exception safety: if an exception occurs, the original value stays intact
For the **const** version, an object key or array index in `ptr` that does not exist is not reported by an
exception, but is undefined behavior (see the notes below). Use [`at`](at.md) for checked access.
If the **non-const** version throws, the value is left unchanged: values it created for earlier reference tokens
of `ptr` are removed again. This also holds for exceptions such as `#!cpp std::bad_alloc` or
`#!cpp std::length_error` thrown while padding an array up to a very large index. With custom
[template parameters](../../features/types/template_parameters.md), this requires that `erase()` of the object and
array types and the move operations of the custom base class do not throw.
## Complexity
1. Constant if `idx` is in the range of the array. Otherwise, linear in `idx - size()`.
2. Logarithmic in the size of the container.
3. Logarithmic in the size of the container.
4. Linear in the number of reference tokens of `ptr`; for each of them, logarithmic in the size of the object, or
constant for an array. When the non-const version pads an array with `#!json null` values, it is additionally
linear in `idx - size()` for that array.
4. Logarithmic in the size of the container.
## Notes
@@ -145,21 +137,10 @@ Strong exception safety: if an exception occurs, the original value stays intact
When the JSON pointer traverses intermediate levels that don't exist at all yet (not just a missing
leaf), each missing level is created as an array or an object depending on whether the corresponding
pointer token is a valid array index: the token `0`, a sequence of digits that does not begin with `0`,
or the token `-` creates an array, and every other token creates an object. For example, on an
initially `#!json null` value, `/foo/0/0/0` creates nested arrays, while `/foo/one/one/one` creates
nested objects. Tokens such as `01` or the empty token cannot be array indices (cf. RFC 6901, Sect. 4)
and therefore create objects, just as they would if the level already existed as an object. This is not
specified by the JSON Pointer RFC; it is this library's own, intentional disambiguation rule. See also
[JSON Pointer](../../features/json_pointer.md).
!!! warning "Large array indices"
As the array is filled up with `#!json null` values to the given index, the memory used grows with the index
and not with the size of the pointer: on a 64-bit platform, the index `10000000` allocates about 160 MB.
The library does not limit the index, so check the array indices of a JSON pointer from untrusted input
before using it with the non-const version. See
[Parsing untrusted input](../../features/parsing/untrusted_input.md#json-pointers-and-flattened-keys).
pointer token parses as a non-negative integer: a numeric token creates an array, a non-numeric token
creates an object. For example, on an initially `#!json null` value, `/foo/0/0/0` creates nested arrays,
while `/foo/one/one/one` creates nested objects. This is not specified by the JSON Pointer RFC; it is
this library's own, intentional disambiguation rule. See also [JSON Pointer](../../features/json_pointer.md).
!!! warning "Deprecation"
@@ -303,13 +284,11 @@ Strong exception safety: if an exception occurs, the original value stays intact
1. Added in version 1.0.0. Fixed in version 3.13.0 to throw `#!cpp std::length_error` instead of emptying the array and
accessing it out of bounds when `idx` equals the maximum value of `size_type`. A missing index in the const version
is guarded by a runtime assertion since version 3.13.0.
2. Added in version 1.0.0. Added overloads for `T* key` in version 1.1.0. The `T* key` overloads forward to
overload 3 since version 3.11.0.
3. Added in version 3.11.0. Support for keys convertible to `std::string_view` added in version 3.13.0, consistently
across the lookup functions.
2. Added in version 1.0.0. Added overloads for `T* key` in version 1.1.0. Removed overloads for `T* key` (replaced by 3)
in version 3.11.0.
3. Added in version 3.11.0. Fixed in version 3.13.0 to consistently accept `std::string_view`-convertible keys, as
already supported by [`at`](at.md), [`value`](value.md), [`find`](find.md), and other lookup functions.
4. Added in version 2.0.0. A missing array index in the const version is guarded by a runtime assertion since
version 3.13.0. Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) instead of
[`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) for a one-character array index that is not
a digit (e.g., `/x`) in version 3.13.0, as it already did for longer ones. Fixed in version 3.13.0 to leave the value
unchanged if the non-const version throws (strong exception safety, as documented); before, values created for earlier
reference tokens of `ptr` were kept.
a digit (e.g., `/x`) in version 3.13.0, as it already did for longer ones.
@@ -89,6 +89,6 @@ Linear in the size of the JSON value.
## Version history
- Added in version 1.0.0.
- Since version 1.0.0.
- Macros `JSON_EXPLICIT`/[`JSON_USE_IMPLICIT_CONVERSIONS`](../macros/json_use_implicit_conversions.md) added
in version 3.9.0.
@@ -75,4 +75,4 @@ classDiagram
## Version history
- Added in version 3.0.0.
- Since version 3.0.0.
@@ -76,4 +76,4 @@ classDiagram
## Version history
- Added in version 3.0.0.
- Since version 3.0.0.
+1 -34
View File
@@ -25,10 +25,6 @@ static basic_json parse(IteratorType first, SentinelType last,
respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
the iterator type with `operator!=`.
Ill-formed UTF-16 and UTF-32 sequences are rejected: a lone surrogate, a high surrogate that is not followed by its
low surrogate, and a code point above `U+10FFFF` all yield a
[`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101).
## Template parameters
`InputType`
@@ -38,12 +34,9 @@ static basic_json parse(IteratorType first, SentinelType last,
- a `FILE` pointer (throws if null)
- a C-style array of characters
- a pointer to a null-terminated string of single byte characters (throws if null)
- a `std::string` or a `std::string_view` (C++17)
- a `std::string`
- a container `obj` for which `begin(obj)` and `end(obj)` produce a valid pair of iterators
(as found via ADL or member functions, with semantics compatible to `std::begin` and `std::end`)
- wide characters (`wchar_t`, `char16_t`, `char32_t`), which are converted to UTF-8: a wide string object
(`std::wstring`, `std::u16string`, `std::u32string`) or an array (e.g. a wide string literal); a pointer to a
null-terminated wide string (e.g. `std::u16string::c_str()`) is not supported
`IteratorType`
: a compatible iterator type, for instance.
@@ -119,13 +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 "Parsing into a document instead of a value"
[`basic_json_document::parse`](../basic_json_document/parse.md) accepts the same inputs and the same options, but
keeps the result as a flat index of the parsed values instead of a tree of `basic_json` values. It is faster and uses
less memory when only parts of the document are read, and it also accepts a pointer to a null-terminated wide string,
which `parse()` does not. See [Zero-copy JSON views](../../features/json_view.md).
!!! tip "Performance"
Contiguous inputs (strings, string views, vectors, arrays, pointer ranges) are the fastest to parse. A
@@ -264,22 +250,6 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
--8<-- "examples/trailing_commas.output"
```
??? example "Example: parse from UTF-16, UTF-32, and wide strings"
The encoding is deduced from the character type of the input; `std::u16string` and `std::u32string` are interpreted
as UTF-16 and UTF-32, and `std::wstring` uses the platform's `wchar_t` width. String literals like `u"..."`,
`U"..."`, and `L"..."` work as well, as do iterators over wide characters.
```cpp
--8<-- "examples/parse__wide_string.cpp"
```
Output:
```json
--8<-- "examples/parse__wide_string.output"
```
## See also
- [accept](accept.md) - check if the input is valid JSON
@@ -310,9 +280,6 @@ outside of a string, invalid) byte; see the [FAQ entry](../../home/faq.md#nul-by
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`).
- Ill-formed UTF-16 and UTF-32 input (a lone surrogate, a high surrogate that is not followed by its low surrogate, or
a code point above `U+10FFFF`) is rejected with `parse_error.101` in version 3.13.0; before that, some such
sequences were accepted or ended the input silently.
!!! warning "Deprecation"
@@ -84,4 +84,4 @@ or the end of file. This also holds true when reading a byte vector for binary f
## Version history
- Added in version 3.0.0.
- Since version 3.0.0.
+2 -10
View File
@@ -40,7 +40,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
where an existing element is required (the "path" of "replace", the "from" of "move" and "copy"); example:
`"array index '-' (3) is out of range"`.
- Throws [`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403) if a JSON pointer inside the patch
could not be resolved successfully in the current JSON value; example: `"key 'baz' not found"`.
could not be resolved successfully in the current JSON value; example: `"key baz not found"`.
- Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if a reference token of a JSON
pointer inside the patch cannot be resolved, e.g., `-` in a "remove" operation or `1a` for an array; example:
`"unresolved reference token '-'"`.
@@ -53,10 +53,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
- Throws [`out_of_range.414`](../../home/exceptions.md#jsonexceptionout_of_range414) if a "move" operation's "from"
location is a proper prefix of its "path" location.
- Throws [`other_error.501`](../../home/exceptions.md#jsonexceptionother_error501) if "test" operation was
unsuccessful. A "test" operation whose "path" does not exist is unsuccessful, too: the failed lookup is reported as a
failed test, even if the operation has no "value" member (which would otherwise be
[`parse_error.105`](../../home/exceptions.md#jsonexceptionparse_error105)). Which of the two errors is reported for
this combination depends on the order in which the operands of a comparison are evaluated, so do not rely on it.
unsuccessful.
## Complexity
@@ -68,10 +65,6 @@ the JSON value, the complexity can usually be neglected.
The application of a patch is atomic: Either all operations succeed and the patched document is returned or an exception
is thrown. In any case, the original value is not changed: the patch is applied to a copy of the value.
Duplicate member names inside an operation object are resolved by the parser before the patch is applied (the last one
is kept, see [`object_t`](object_t.md#behavior)), so `#!json {"op": "add", "op": "remove", "path": "/a"}` is a
`remove` operation.
## Examples
??? example "Example: apply a JSON patch"
@@ -115,7 +108,6 @@ is kept, see [`object_t`](object_t.md#behavior)), so `#!json {"op": "add", "op":
- Added in version 2.0.0.
- Added [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) and stopped relying on an internal assertion when an "add" operation's
target location has a non-object/non-array parent in version 3.13.0.
This includes a `null` parent, which was previously silently converted to an object, in version 3.13.0.
- Added [`out_of_range.413`](../../home/exceptions.md#jsonexceptionout_of_range413) and stopped silently ignoring a "remove" operation whose target
location has a non-object/non-array parent in version 3.13.0.
- Added [`out_of_range.414`](../../home/exceptions.md#jsonexceptionout_of_range414) and rejected a "move" operation whose "from" location is a proper
@@ -36,7 +36,7 @@ No guarantees, value may be corrupted by an unsuccessful patch operation.
where an existing element is required (the "path" of "replace", the "from" of "move" and "copy"); example:
`"array index '-' (3) is out of range"`.
- Throws [`out_of_range.403`](../../home/exceptions.md#jsonexceptionout_of_range403) if a JSON pointer inside the patch
could not be resolved successfully in the current JSON value; example: `"key 'baz' not found"`.
could not be resolved successfully in the current JSON value; example: `"key baz not found"`.
- Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if a reference token of a JSON
pointer inside the patch cannot be resolved, e.g., `-` in a "remove" operation or `1a` for an array; example:
`"unresolved reference token '-'"`.
@@ -49,10 +49,7 @@ No guarantees, value may be corrupted by an unsuccessful patch operation.
- Throws [`out_of_range.414`](../../home/exceptions.md#jsonexceptionout_of_range414) if a "move" operation's "from"
location is a proper prefix of its "path" location.
- Throws [`other_error.501`](../../home/exceptions.md#jsonexceptionother_error501) if "test" operation was
unsuccessful. A "test" operation whose "path" does not exist is unsuccessful, too: the failed lookup is reported as a
failed test, even if the operation has no "value" member (which would otherwise be
[`parse_error.105`](../../home/exceptions.md#jsonexceptionparse_error105)). Which of the two errors is reported for
this combination depends on the order in which the operands of a comparison are evaluated, so do not rely on it.
unsuccessful.
## Complexity
@@ -65,10 +62,6 @@ Unlike [`patch`](patch.md), `patch_inplace` applies the operation "in place" and
That makes it faster for large documents by avoiding the copy. However, the JSON value might be corrupted if the
function throws an exception.
Duplicate member names inside an operation object are resolved by the parser before the patch is applied (the last one
is kept, see [`object_t`](object_t.md#behavior)), so `#!json {"op": "add", "op": "remove", "path": "/a"}` is a
`remove` operation.
## Examples
??? example "Example: apply a JSON patch in place"
@@ -113,7 +106,6 @@ is kept, see [`object_t`](object_t.md#behavior)), so `#!json {"op": "add", "op":
- Added in version 3.11.0.
- Added [`out_of_range.411`](../../home/exceptions.md#jsonexceptionout_of_range411) and stopped relying on an internal assertion when an "add" operation's
target location has a non-object/non-array parent in version 3.13.0.
This includes a `null` parent, which was previously silently converted to an object, in version 3.13.0.
- Added [`out_of_range.413`](../../home/exceptions.md#jsonexceptionout_of_range413) and stopped silently ignoring a "remove" operation whose target
location has a non-object/non-array parent in version 3.13.0.
- Added [`out_of_range.414`](../../home/exceptions.md#jsonexceptionout_of_range414) and rejected a "move" operation whose "from" location is a proper
+3 -3
View File
@@ -125,6 +125,6 @@ throws.
## Version history
1. Added in version 1.0.0.
2. Added in version 1.0.0.
3. Added in version 2.0.0.
1. Since version 1.0.0.
2. Since version 1.0.0.
3. Since version 2.0.0.
@@ -31,10 +31,6 @@ Read from input and generate SAX events
respectively as UTF-8, UTF-16, and UTF-32. If `SentinelType` differs from `IteratorType`, it must be comparable to
the iterator type with `operator!=`.
Ill-formed UTF-16 and UTF-32 sequences are rejected: a lone surrogate, a high surrogate that is not followed by its
low surrogate, and a code point above `U+10FFFF` all yield a
[`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101).
The SAX event lister must follow the interface of [`json_sax`](../json_sax/index.md).
## Template parameters
@@ -46,12 +42,8 @@ The SAX event lister must follow the interface of [`json_sax`](../json_sax/index
- a `FILE` pointer
- a C-style array of characters
- a pointer to a null-terminated string of single byte characters
- a `std::string` or a `std::string_view` (C++17)
- a container `obj` for which `begin(obj)` and `end(obj)` produce a valid pair of iterators
(as found via ADL or member functions, with semantics compatible to `std::begin` and `std::end`)
- wide characters (`wchar_t`, `char16_t`, `char32_t`), which are converted to UTF-8: a wide string object
(`std::wstring`, `std::u16string`, `std::u32string`) or an array (e.g. a wide string literal); a pointer to a
null-terminated wide string (e.g. `std::u16string::c_str()`) is not supported
`IteratorType`
: a compatible iterator type for overload (2); a pair of character iterators whose `value_type` is an integral type
@@ -168,9 +160,6 @@ use the same file with stdio functions, but it must not wait for another thread
([`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)).
- Ill-formed UTF-16 and UTF-32 input (a lone surrogate, a high surrogate that is not followed by its low surrogate, or
a code point above `U+10FFFF`) is rejected with `parse_error.101` in version 3.13.0; before that, some such
sequences were accepted or ended the input silently.
!!! warning "Deprecation"
+7 -7
View File
@@ -182,10 +182,10 @@ Constant.
## Version history
1. Added in version 1.0.0. Exchanges the `json_base_class_t` subobject along with the value since version 3.13.0.
2. Added in version 1.0.0. Exchanges the `json_base_class_t` subobject along with the value since version 3.13.0.
3. Added in version 1.0.0.
4. Added in version 1.0.0.
5. Added in version 1.0.0.
6. Added in version 3.8.0.
7. Added in version 3.8.0.
1. Since version 1.0.0. Exchanges the `json_base_class_t` subobject along with the value since version 3.13.0.
2. Since version 1.0.0. Exchanges the `json_base_class_t` subobject along with the value since version 3.13.0.
3. Since version 1.0.0.
4. Since version 1.0.0.
5. Since version 1.0.0.
6. Since version 3.8.0.
7. Since version 3.8.0.
+4 -5
View File
@@ -43,8 +43,7 @@ The exact mapping and its limitations are described on a [dedicated page](../../
`#!cpp false` by default.
`version` (in)
: which version of BJData to use, see [`bjdata_version_t`](bjdata_version_t.md) and the note on "Binary values" on
[BJData](../../features/binary_formats/bjdata.md);
: which version of BJData to use (see note on "Binary values" on [BJData](../../features/binary_formats/bjdata.md));
optional, `#!cpp bjdata_version_t::draft2` by default.
`error_handler` (in)
@@ -65,9 +64,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
## Exceptions
- Throws [`other_error.502`](../../home/exceptions.md#jsonexceptionother_error502) if `use_type` is true and `use_size`
is false, and `j` contains a non-empty array or object, or a non-empty binary value (with
`version = bjdata_version_t::draft3`, any binary value, including an empty one).
Scalars, empty arrays, and empty objects do not throw.
is false, and `j` contains a non-empty array, object, or binary value.
- 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)
@@ -127,3 +124,5 @@ Linear in the size of the JSON value `j`.
[`JSON_STRICT_BINARY_UTF8`](../macros/json_strict_binary_utf8.md) is enabled) throws `type_error.316`.
- Throws `type_error.321` for a discarded value since version 3.13.0; previously, a discarded value nested in an
array or object was silently skipped, producing invalid 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.
+1 -1
View File
@@ -13,7 +13,7 @@ static void to_bson(const basic_json& j, detail::output_adapter<char> o,
```
BSON (Binary JSON) is a binary format in which zero or more ordered key/value pairs are stored as a single entity (a
so-called document). The members of an object are written in the order in which iteration visits them.
so-called document).
1. Returns a byte vector containing the BSON serialization.
2. Writes the BSON serialization to an output adapter.
+1 -2
View File
@@ -42,8 +42,7 @@ The exact mapping and its limitations are described on a [dedicated page](../../
## Exception safety
Strong guarantee: if an exception is thrown, there are no changes in the JSON value. Bytes that were already written to
the output adapter are not taken back.
Strong guarantee: if an exception is thrown, there are no changes in the JSON value.
## Exceptions
@@ -53,7 +53,7 @@ Strong guarantee: if an exception is thrown, there are no changes in the JSON va
value, array, or object exceeds 4294967295, the maximum MessagePack can store; example:
`"MessagePack length 4294967296 exceeds maximum of 4294967295"`
- Throws [`out_of_range.415`](../../home/exceptions.md#jsonexceptionout_of_range415) if the subtype of a binary value
exceeds 255, the largest value the library can store in the one-byte MessagePack ext type; example:
exceeds 255, the maximum of the MessagePack ext type; example:
`"subtype 70000 is too large for the MessagePack ext type (max 255)"`
- 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`
@@ -76,4 +76,4 @@ classDiagram
## Version history
- Added in version 3.0.0.
- Since version 3.0.0.
+5 -10
View File
@@ -36,9 +36,9 @@ The function can throw the following exceptions:
- Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) if an array index in a key is not a
number; example: `"array index 'one' is not a number"`
- Throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404) if a level becomes an array
(because one of its keys is `0`) and another key at that level is empty (as in `/a/`), is `-`, or begins with a digit
but is not a valid array index (such as `1a`); examples: `"unresolved reference token '-'"`,
`"unresolved reference token ''"`
(because one of its keys is `0`) and another key at that level begins with a digit but is not a valid array index
(such as `1a`), or is `-`; example:
`"unresolved reference token '-'"`
## Complexity
@@ -46,7 +46,7 @@ Linear in the size of the JSON value.
## Notes
Empty objects and arrays are flattened by [`flatten()`](flatten.md) to `#!json null` values and cannot be unflattened to
Empty objects and arrays are flattened by [`flatten()`](flatten.md) to `#!json null` values and cannot unflattened to
their original type.
A flattened array and a flattened object whose keys are array indices are indistinguishable, because both are
@@ -54,12 +54,7 @@ described by the same JSON pointers. A value is therefore restored as an array i
reference token `0`, and as an object otherwise: `#!json {"2": 1}` is restored unchanged, whereas `#!json {"0": 1}` is
restored as `#!json [1]`. This decision does not depend on the order in which the flattened object is iterated.
A third case is an object that has the key `0` next to a key that is not a valid array index: `#!json {"0": 1, "b": 2}`
is flattened to `#!json {"/0": 1, "/b": 2}`, and unflatten treats the level as an array and throws
[`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109) because `b` is not a number. (For the keys
`-`, `1a`, or the empty key instead of `b`, it throws [`out_of_range.404`](../../home/exceptions.md#jsonexceptionout_of_range404).)
Apart from these three cases, for a JSON value `j`, the following is always true:
Apart from these two cases, for a JSON value `j`, the following is always true:
`#!cpp j == j.flatten().unflatten()`.
## Examples
+6 -6
View File
@@ -45,9 +45,6 @@ This is equivalent to Python's `dict.get(key, default)`.
return default_value;
}
```
with one exception: if the JSON value is neither an array nor an object, the function throws
[`type_error.306`](../../home/exceptions.md#jsonexceptiontype_error306) before looking at `ptr`, even for the empty
pointer, whereas `at` returns the value itself for the empty pointer.
!!! note "Differences to `at` and `operator[]`"
@@ -234,8 +231,11 @@ changes to any JSON value.
1. Added in version 1.0.0. Changed parameter `default_value` type from `const ValueType&` to `ValueType&&` in version
3.11.0. Deleted overload for integral key types added in version 3.13.0 to reject such calls at compile time
instead of causing undefined behavior at runtime.
2. Added in version 3.11.0. Made `ValueType` the first template parameter in version 3.11.2. Support for keys
convertible to `std::string_view` added in version 3.13.0, consistently across the lookup functions.
3. Added in version 2.0.2. Extended to work with arrays in version 3.13.0. Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109)
2. Added in version 3.11.0. Made `ValueType` the first template parameter in version 3.11.2. Fixed in version 3.13.0
to consistently accept `std::string_view`-convertible keys, as already supported by
[`operator[]`](operator[].md), [`at`](at.md), [`find`](find.md), and other lookup functions.
3. Added in version 2.0.2. Extended to work with arrays in version 3.13.0, including fixing an issue where resolving
`ptr` through an array unexpectedly threw `out_of_range` instead of returning the resolved element (or
`default_value`, as documented). Throws [`parse_error.109`](../../home/exceptions.md#jsonexceptionparse_error109)
instead of returning `default_value` for a one-character array index that is not a digit (e.g., `/x`) in version
3.13.0, as it already did for longer ones.
@@ -12,7 +12,7 @@ void erase(view_type array, I idx);
std::size_t erase(const json_pointer& ptr);
```
Only an **editable** document (`#!cpp view_mode::editable`, e.g. [`json_editable_document`](../json_editable_document.md))
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
@@ -3,14 +3,14 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
template<typename BasicJsonType, view_mode Mode = view_mode::read_only>
template<typename BasicJsonType, bool Editable = false>
class basic_json_document;
```
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 floating-point numbers stay in the source text; integers are converted while parsing, and 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
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
`BasicJsonType` value that [`BasicJsonType::parse()`](../basic_json/parse.md) would have produced for it.
@@ -20,9 +20,9 @@ is move-only: a copy would duplicate the whole index, the decoded-string buffer,
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 Mode == view_mode::editable`, the document also offers [`set`](set.md), [`push_back`](push_back.md),
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 view_mode::read_only`, the default) does not carry any of the
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`).
## Template parameters
@@ -32,10 +32,9 @@ 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`.
`Mode`
: a [`view_mode`](../view_mode.md): `#!cpp view_mode::editable` if the document supports [`set`](set.md),
[`push_back`](push_back.md), [`insert`](insert.md), and [`erase`](erase.md) (optional, `#!cpp view_mode::read_only`
by default). See [Edits](#edits) below.
`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
@@ -48,7 +47,7 @@ bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp
## Member types
- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType, Mode>`)
- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType, Editable>`)
- **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)
@@ -81,15 +80,15 @@ bookkeeping edits need, and calling any of them on one fails to compile (`#!cpp
### Edits
- [**set**](set.md) - replace a value, or set an object member, an array element, or the value a JSON pointer refers
to (editable documents only)
- [**push_back**](push_back.md) - append to an array (editable documents only)
- [**insert**](insert.md) - insert an element into an array before a given position (editable documents only)
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
(editable documents only)
(`#!cpp Editable` documents only)
## Edits
An editable document (`#!cpp view_mode::editable`) can be changed after parsing, with [`set`](set.md),
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
@@ -116,13 +115,6 @@ points apply to every edit:
[`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.
## See also
- [Zero-copy JSON views](../../features/json_view.md) - guide to documents and views
- [**basic_json_view**](../basic_json_view/index.md) - the non-owning handle to a value in a document
- [**json_document**](../json_document.md) and [**json_editable_document**](../json_editable_document.md) - the default specializations
- [**materialize**](../basic_json_view/materialize.md) - build a `basic_json` value from a view
## Version history
- Added in version 3.13.0.
@@ -5,7 +5,7 @@ template<typename I, typename V>
view_type insert(view_type array, I idx, V&& value);
```
Only an **editable** document (`#!cpp view_mode::editable`, e.g. [`json_editable_document`](../json_editable_document.md))
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
@@ -55,7 +55,10 @@ validate with overload 2 first, if the original vector must survive a failed loa
## Exceptions
Throws [`parse_error.116`](../../home/exceptions.md#jsonexceptionparse_error116) if `image` is not one
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 |
@@ -92,9 +95,6 @@ are checked once, however many nodes refer to it.
## Notes
**Little-endian targets only.** On a big-endian target, `load()` does not exist, just like
[`save()`](save.md#notes): the image format is little-endian, so a call fails to compile.
### `image_check` { #image_check }
```cpp
@@ -21,19 +21,17 @@ 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 accept every input `BasicJsonType::parse()` takes, and in
addition a pointer to a null-terminated wide string (which `BasicJsonType::parse()` rejects). Contiguous inputs of
single-byte characters that stay alive can be borrowed; all others (streams, `#!cpp FILE*`, wide characters, which
must be converted to UTF-8, and 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. 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.
## Template parameters
`InputType`
: A compatible input, for instance:
- a `#!cpp std::string`, a `#!cpp std::string_view` (C++17), or a C-style array of single-byte characters
- 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`,
`#!cpp unsigned char`, `#!cpp std::uint8_t`)
- a container for which `#!cpp obj.data()` and `#!cpp obj.size()` give contiguous single-byte access, e.g.
@@ -49,10 +47,6 @@ as well.
`#!cpp std::string::iterator`; the iterators of single-byte characters are borrowed or read like the byte inputs
above, those of wide characters are converted to UTF-8
Ill-formed UTF-16 and UTF-32 sequences are rejected: a lone surrogate, a high surrogate that is not followed by its low
surrogate, and a code point above `U+10FFFF` all yield a
[`parse_error.101`](../../home/exceptions.md#jsonexceptionparse_error101).
## Parameters
`input` (in)
@@ -161,5 +155,3 @@ buffer of a given length, pass a pair of pointers: `#!cpp parse(ptr, ptr + len)`
## Version history
- Added in version 3.13.0.
- Ill-formed UTF-16 and UTF-32 input (a lone surrogate, a high surrogate that is not followed by its low surrogate, or
a code point above `U+10FFFF`) is rejected with `parse_error.101`.
@@ -13,7 +13,7 @@ editable, and it does not have to be `array`'s own document -- which is copied s
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 view_mode::editable`, e.g. [`json_editable_document`](../json_editable_document.md))
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
@@ -12,7 +12,7 @@ An edited document is written in its *current* state, with its values in documen
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 the [`view_mode`](../view_mode.md), since the image reflects document order and
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
@@ -31,6 +31,9 @@ Throws [`type_error.320`](../../home/exceptions.md#jsonexceptiontype_error320) i
[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.
@@ -41,6 +44,9 @@ the decoded strings of the image would individually reach 4 GiB -- the same 32-b
[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
```
@@ -64,9 +70,9 @@ else -- see [`load`'s Exceptions](load.md#exceptions).
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 targets only.** The image is written as raw little-endian bytes, with no byte-swapping. On a
big-endian target, `save()` and [`load`](load.md) do not exist: a call fails to compile rather than produce bytes a
big-endian reader could not interpret correctly.
**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
@@ -18,7 +18,7 @@ template<typename V>
view_type set(const json_pointer& ptr, V&& value);
```
Only an **editable** document (`#!cpp view_mode::editable`, e.g. [`json_editable_document`](../json_editable_document.md))
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`.
@@ -23,10 +23,6 @@ Linear in [`node_count()`](node_count.md) plus the length of the decoded strings
## Notes
The node index of a small document (an estimate of up to 1024 nodes, which is up to about 4 KiB of minified text) is
allocated together with the document's header, so that parsing needs one allocation. That part cannot be released
separately: `shrink_to_fit()` only trims a node index that has its own allocation, and the decoded strings.
!!! warning "Invalidates views"
Unlike moving the document, `shrink_to_fit()` **invalidates every view taken from this document before the
+1 -2
View File
@@ -80,8 +80,7 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
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). Constant if no element of the array is an array
or object, since the elements are then adjacent in the index.
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
that level (as 1.) or the index into the array (as 2.).
+1 -2
View File
@@ -28,8 +28,7 @@ This exception does not carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics.
Linear in the size of the array or object: unlike [`front()`](front.md), which only ever looks at the first
element, `back()` has to walk every element to find where they end, since elements are not a fixed size in the
index. Constant if no element of the array is an array or object, since the elements are then adjacent
in the index.
index.
## Notes
@@ -1,32 +1,20 @@
# <small>nlohmann::basic_json_view::</small>basic_json_view
```cpp
// (1)
basic_json_view() noexcept = default;
// (2) only for Mode == view_mode::editable
basic_json_view(const basic_json_view<BasicJsonType, view_mode::read_only>& other) noexcept;
```
1. Creates an invalid (discarded) view: [`type()`](type.md) is `#!cpp value_t::discarded` and
[`is_discarded()`](is_discarded.md) is `#!cpp true`.
2. Converts a view of a read-only document into a view of an editable document (implicitly), so that a function
taking a [`json_editable_view`](../json_editable_view.md) accepts both. The result is a view of the same value of
the same read-only document. See [`view_mode`](../view_mode.md) for why there is no conversion the other way.
Creates an invalid (discarded) view: [`type()`](type.md) is `#!cpp value_t::discarded` and
[`is_discarded()`](is_discarded.md) is `#!cpp true`.
## Parameters
`other` (in)
: a view of a read-only document with the same `BasicJsonType`
Apart from these, a view is obtained from a
This is the only constructor a caller can use directly. Every other view is obtained from a
[`basic_json_document`](../basic_json_document/index.md), via [`root()`](../basic_json_document/root.md) or by
navigating into a container with [`operator[]`](operator[].md), [`at`](at.md), [`front`](front.md), [`back`](back.md),
[`find`](find.md), or iteration.
## Exception safety
No-throw guarantee: these constructors never throw exceptions.
No-throw guarantee: this constructor never throws exceptions.
## Complexity
@@ -57,7 +45,6 @@ placeholder for "no value yet" and later be assigned a real view.
- [is_discarded](is_discarded.md) - return whether the view is invalid
- [root](../basic_json_document/root.md) - the view of a document's root value
- [view_mode](../view_mode.md) - whether a document and its views can be edited
## Version history
+12 -37
View File
@@ -19,36 +19,16 @@ 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>` of the types above -- from an array, element by element, each converted with
`#!cpp get<U>()`; `#!cpp std::vector<basic_json_view>` keeps a view of every element instead of a value
- `#!cpp std::map<K, basic_json_view, C, A>` and `#!cpp std::unordered_map<K, basic_json_view, H, E, A>`, if `K` is
constructible from a `#!cpp (const char*, std::size_t)` pair -- views of the members of an object; with a repeated
key, the view of the *last* member is kept, as [`BasicJsonType::parse()`](../basic_json/parse.md) keeps its value
- `#!cpp std::vector<U, A>` -- from an array, element by element, each converted with `#!cpp get<U>()`; `#!cpp
std::vector<basic_json_view>` keeps a view of every element instead of a value
- `#!cpp std::map<K, V, C, A>` and `#!cpp std::unordered_map<K, V, H, E, A>`, if `K` is constructible from a `#!cpp
(const char*, std::size_t)` pair -- from an object, member by member, each value converted with `#!cpp get<V>()`; with a repeated
key, the *last* value is kept, as [`BasicJsonType::parse()`](../basic_json/parse.md) (and
[`materialize()`](materialize.md)) does; `#!cpp std::map<std::string, basic_json_view>` keeps views of the members
instead of values
A default-constructible `T` whose `from_json()` accepts views reads the view directly as well, without building a
`BasicJsonType` value. This covers the library's own conversions of the standard library types -- all other
`#!cpp std::vector`s, `#!cpp std::map`/`#!cpp std::unordered_map` (also with other key types), `#!cpp std::list`,
`#!cpp std::deque`, `#!cpp std::set`, `#!cpp std::forward_list`, `#!cpp std::valarray`, `#!cpp std::array`, C arrays,
`#!cpp std::pair`, `#!cpp std::tuple`, `#!cpp std::optional`, enumerations, `#!cpp std::filesystem::path`, ... --
which give the same values as `#!cpp materialize().get<T>()` (from an object, a repeated key keeps the *last* value,
as [`BasicJsonType::parse()`](../basic_json/parse.md) does), as well as the types of the
[`NLOHMANN_DEFINE_TYPE_*`](../macros/nlohmann_define_type_intrusive.md) and
[`NLOHMANN_DEFINE_DERIVED_TYPE_*`](../macros/nlohmann_define_derived_type.md) macros and the enumerations of
[`NLOHMANN_JSON_SERIALIZE_ENUM`](../macros/nlohmann_json_serialize_enum.md), and any `from_json()` constrained to
accept views, e.g. with [`is_json_view`](../is_json_view.md). A `from_json()` that also accepts types that are no JSON
values at all, such as the unconstrained `#!cpp template<typename BasicJsonType> void from_json(const BasicJsonType&,
T&)` of [arbitrary type conversions](../../features/arbitrary_types.md), is not called with a view: it may use
`BasicJsonType` functions a view does not have. See [Writing generic code](../../features/json_view.md#writing-generic-code).
!!! warning "Duplicate keys"
Such a `from_json()` looks members up in the view, where a repeated key finds the **first** member, while
`#!cpp materialize().get<T>()` sees the **last** one, as [`BasicJsonType::parse()`](../basic_json/parse.md)
keeps it: for `#!cpp {"x":1,"x":2}`, `#!cpp get<point>()` reads `#!cpp x == 1`. See
[Duplicate keys](../../features/json_view.md#duplicate-keys).
Every other `T` -- user types whose `from_json()` is written for `BasicJsonType` only, types without a default
constructor, `#!cpp std::tuple`s holding references, ... -- is converted by `#!cpp materialize().get<T>()`: the subtree is built into a real `BasicJsonType`
Every other `T` -- `#!cpp std::list`, `#!cpp std::pair`, `#!cpp std::array`, enumerations, user types with a
`from_json()`, ... -- is converted by `#!cpp materialize().get<T>()`: the subtree is built into a real `BasicJsonType`
value first (as [`BasicJsonType::parse()`](../basic_json/parse.md) would), and converted from there exactly as
[`BasicJsonType::get<T>()`](../basic_json/get.md) would convert it.
@@ -73,15 +53,12 @@ Strong guarantee: there are no changes to the view or the document it refers to.
throws for the same JSON type and `T`.
- For `#!cpp std::vector<U, A>`: throws `type_error.302` if the value is not an array; otherwise, whatever converting
an element to `U` throws.
- For `#!cpp std::map`/`#!cpp std::unordered_map` of views: throws `type_error.302` if the value is not an object.
- For a `T` whose `from_json()` reads the view: whatever that `from_json()` throws; for the library's conversions and
the macros, the same exceptions with the same messages as [`BasicJsonType::get<T>()`](../basic_json/get.md) of the
same value.
- For `#!cpp std::map`/`#!cpp std::unordered_map`: throws `type_error.302` if the value is not an object; otherwise,
whatever converting a member to the mapped type throws.
- For every other `T`: whatever [`materialize().get<T>()`](../basic_json/get.md) throws -- typically `type_error.302`,
or whatever a user-provided `from_json()` throws.
None of the exceptions thrown directly by this function or by a `from_json()` that reads the view (the first four
bullets above) carry a
None of the exceptions thrown directly by this function (the first three bullets above) carry a
[`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.
@@ -99,8 +76,6 @@ 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.
- a `T` whose `from_json()` reads the view: the cost of that `from_json()`; for the macros, linear in the number of
members times the cost of a lookup, plus the cost of converting the members.
- 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).
@@ -5,13 +5,12 @@ template<typename T>
T& get_to(T& v) const;
```
Converts the value to `T` and stores it in `v`, in one of three ways:
Converts the value to `T` and stores it in `v`, in one of two ways:
- 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`, vectors of these, and maps of views -- `v` is assigned: `#!cpp v = get<T>()`.
- For a type whose `from_json()` accepts views (see [`get<T>()`](get.md)), that `from_json()` is called with the
view and the existing `v`, without building a `BasicJsonType` value.
`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.
+5 -14
View File
@@ -3,7 +3,7 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
template<typename BasicJsonType, view_mode Mode = view_mode::read_only>
template<typename BasicJsonType, bool Editable = false>
class basic_json_view;
```
@@ -37,7 +37,7 @@ Moving the document itself does not invalidate its views: the index is heap-allo
`#!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 view_mode::editable`) sees every edit made through
**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
@@ -49,10 +49,9 @@ 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.
`Mode`
: a [`view_mode`](../view_mode.md): whether the view is of an editable document, matching the
[`basic_json_document`](../basic_json_document/index.md) it was taken from (optional, `#!cpp view_mode::read_only` by
default). See [Edits](../basic_json_document/index.md#edits).
`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
@@ -64,7 +63,6 @@ still refers to it -- including ones taken before the change -- reads the new va
## Member types
- **basic_json_type** - `BasicJsonType` (it also marks the class for [`is_json_view`](../is_json_view.md))
- **value_t** - the JSON type enumeration, see [`basic_json::value_t`](../basic_json/value_t.md)
- **string_t**, **number_integer_t**, **number_unsigned_t**, **number_float_t**, **json_pointer** - the corresponding
member types of `BasicJsonType`
@@ -145,13 +143,6 @@ still refers to it -- including ones taken before the change -- reads the new va
- [**source_offset**](source_offset.md) - byte offset of this value in the document's source text
## See also
- [Zero-copy JSON views](../../features/json_view.md) - guide to documents and views
- [**basic_json_document**](../basic_json_document/index.md) - the document that owns the parsed data
- [**json_view**](../json_view.md) and [**json_editable_view**](../json_editable_view.md) - the default specializations
- [**materialize**](materialize.md) - build a `basic_json` value from a view
## Version history
- Added in version 3.13.0.
@@ -86,8 +86,7 @@ None of these exceptions carry a [`JSON_DIAGNOSTICS`](../macros/json_diagnostics
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). Constant if no element of the array is an array
or object, since the elements are then adjacent in the index.
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
that level (as 1.) or the index into the array (as 2.).
@@ -51,4 +51,4 @@ byte_container_with_subtype(container_type&& container, subtype_type subtype);
## Version history
Added in version 3.8.0.
Since version 3.8.0.
@@ -39,4 +39,4 @@ Constant.
## Version history
Added in version 3.8.0.
Since version 3.8.0.
@@ -42,4 +42,4 @@ Constant.
## Version history
Added in version 3.8.0.
Since version 3.8.0.
@@ -6,7 +6,7 @@ class byte_container_with_subtype : public BinaryType;
```
This type extends the template parameter `BinaryType` provided to [`basic_json`](../basic_json/index.md) with a subtype
used by BSON, CBOR, and MessagePack. This type exists so that the user does not have to specify a type themselves with a
used by BSON and MessagePack. This type exists so that the user does not have to specify a type themselves with a
specific naming scheme in order to override the binary type.
## Template parameters
@@ -29,14 +29,6 @@ specific naming scheme in order to override the binary type.
- [**has_subtype**](has_subtype.md) - return whether the value has a subtype
- [**clear_subtype**](clear_subtype.md) - clears the binary subtype
## See also
- [Binary values](../../features/binary_values.md) - how binary values and subtypes are handled
- [**binary**](../basic_json/binary.md) - create a binary array value
- [**get_binary**](../basic_json/get_binary.md) - get a reference to the stored binary value
- [**binary_t**](../basic_json/binary_t.md) - type for binary arrays
- [Binary formats](../../features/binary_formats/index.md) - formats that can store binary values
## Version history
- Added in version 3.8.0.
@@ -44,4 +44,4 @@ Constant.
## Version history
Added in version 3.8.0.
Since version 3.8.0.
-56
View File
@@ -1,56 +0,0 @@
# <small>nlohmann::</small>is_json_view
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
template<typename T>
struct is_json_view;
```
A type trait: `#!cpp is_json_view<T>::value` is `#!cpp true` if `T` is a [`basic_json_view`](basic_json_view/index.md)
of any `BasicJsonType` and any [`view_mode`](view_mode.md) -- [`json_view`](json_view.md),
[`json_editable_view`](json_editable_view.md), [`ordered_json_view`](ordered_json_view.md), ... -- and
`#!cpp false` otherwise, for [`basic_json`](basic_json/index.md) as well.
It is meant for constraining templates that accept views, in particular a `from_json()` that should read views
directly: [`get<T>()`](basic_json_view/get.md) on a view calls a `from_json()` with the view only if that `from_json()`
accepts views but not arbitrary types.
## Template parameters
`T`
: the type to check (without cv-qualifiers or references)
## Notes
A view is recognized by its member type `basic_json_type` (a [`basic_json`](basic_json/index.md) specialization) and
its [`materialize()`](basic_json_view/materialize.md) returning that type, so the trait needs no declaration of the
view class.
## Examples
??? example
The example below shows the trait, and a `from_json()` constrained to `json` values and views: `get<T>()` on a view
reads the view directly.
```cpp
--8<-- "examples/is_json_view.cpp"
```
Output:
```
--8<-- "examples/is_json_view.output"
```
## See also
- [basic_json_view](basic_json_view/index.md) - a handle to one value of a document
- [get](basic_json_view/get.md) - which conversions read the view directly
- [view_mode](view_mode.md) - read-only or editable
- [Writing generic code](../features/json_view.md#writing-generic-code) - functions and `from_json()` for views
## Version history
Added in version 3.13.0.
+1 -1
View File
@@ -30,4 +30,4 @@ types.
## Version history
Added in version 1.0.0.
Since version 1.0.0.
+2 -2
View File
@@ -3,7 +3,7 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using json_document = basic_json_document<json, view_mode::read_only>;
using json_document = basic_json_document<json>;
```
This type is a [`basic_json_document`](basic_json_document/index.md) of the default [`json`](json.md)
@@ -32,4 +32,4 @@ specialization.
## Version history
Added in version 3.13.0.
Since version 3.13.0.
@@ -3,7 +3,7 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using json_editable_document = basic_json_document<json, view_mode::editable>;
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
@@ -40,4 +40,4 @@ parsing, without ever rewriting the source text -- see [Edits](basic_json_docume
## Version history
Added in version 3.13.0.
Since version 3.13.0.
+2 -2
View File
@@ -3,7 +3,7 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using json_editable_view = basic_json_view<json, view_mode::editable>;
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
@@ -38,4 +38,4 @@ still referring to it seeing the change, see [Edits](basic_json_document/index.m
## Version history
Added in version 3.13.0.
Since version 3.13.0.
@@ -51,5 +51,5 @@ operator string_t() const
## Version history
- Added in version 2.0.0.
- Since version 2.0.0.
- Changed type to `string_t` and deprecated in version 3.11.0.
@@ -12,8 +12,7 @@ Parent of this JSON pointer; in case this JSON pointer is the root, the root its
## Exception safety
Strong exception safety: if an exception occurs, the original value stays intact. The function is not `#!cpp noexcept`
and allocates a new JSON pointer, so it can throw `#!cpp std::bad_alloc`; it throws no library exceptions.
No-throw guarantee: this function never throws exceptions.
## Complexity
@@ -49,5 +49,5 @@ ptr == json_pointer(ptr.to_string());
## Version history
- Added in version 2.0.0.
- Since version 2.0.0.
- Changed return type to `string_t` in version 3.11.0.
-7
View File
@@ -59,13 +59,6 @@ leading `-` sign.
- [**start_object**](start_object.md) (_virtual_) - the beginning of an object was read
- [**string**](string.md) (_virtual_) - a string value was read
## See also
- [SAX interface](../../features/parsing/sax_interface.md) - guide to event-based parsing
- [**sax_parse**](../basic_json/sax_parse.md) - generate SAX events from an input
- [**parse**](../basic_json/parse.md) - DOM parsing, with optional [parser callbacks](../../features/parsing/parser_callbacks.md)
- [Parse exceptions](../../features/parsing/parse_exceptions.md)
## Version history
- Added in version 3.2.0.
+2 -2
View File
@@ -3,7 +3,7 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using json_view = basic_json_view<json, view_mode::read_only>;
using json_view = basic_json_view<json>;
```
This type is a [`basic_json_view`](basic_json_view/index.md) of a value of a [`json_document`](json_document.md).
@@ -31,4 +31,4 @@ This type is a [`basic_json_view`](basic_json_view/index.md) of a value of a [`j
## Version history
Added in version 3.13.0.
Since version 3.13.0.
+3 -10
View File
@@ -43,6 +43,8 @@ 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
@@ -135,13 +137,4 @@ header. See also the [macro overview page](../../features/macros.md).
- [**NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_WITH_DEFAULT_WITH_NAMES**](nlohmann_define_type_with_names.md) - serialize/deserialize
a derived class; uses default values; uses custom names
- [**NLOHMANN_DEFINE_DERIVED_TYPE_NON_INTRUSIVE_ONLY_SERIALIZE_WITH_NAMES**](nlohmann_define_type_with_names.md) - serialize a derived
class; uses custom names
## See also
- [Macros](../../features/macros.md) - guide to the supported macros
- [Runtime assertions](../../features/assertions.md)
- [Arbitrary type conversions](../../features/arbitrary_types.md) - using the `NLOHMANN_DEFINE_TYPE_*` macros
- [Enum conversion](../../features/enum_conversion.md) - using `NLOHMANN_JSON_SERIALIZE_ENUM`
- [The `nlohmann` namespace](../../features/namespace.md)
- [CMake integration](../../integration/cmake.md) - setting macros from the build system
class; uses custom names
+2 -2
View File
@@ -38,7 +38,7 @@ Therefore, assertions can be switched off by defining `NDEBUG`.
```cpp
#include <nlohmann/json.hpp>
using nlohmann::json;
using json = nlohmann::json;
int main()
{
@@ -64,7 +64,7 @@ Therefore, assertions can be switched off by defining `NDEBUG`.
#include <nlohmann/json.hpp>
using nlohmann::json;
using json = nlohmann::json;
int main()
{
@@ -79,7 +79,7 @@ The default value is `0` (disabled — existing behavior is preserved).
```cpp
#include <nlohmann/json.hpp>
using nlohmann::json;
using json = nlohmann::json;
int main()
{
@@ -98,7 +98,7 @@ The default value is `0` (disabled — existing behavior is preserved).
#define JSON_BRACE_INIT_COPY_SEMANTICS 1
#include <nlohmann/json.hpp>
using nlohmann::json;
using json = nlohmann::json;
int main()
{
@@ -54,7 +54,7 @@ The default value is `0` (disabled, the deprecated functions can still be called
```cpp
#include <nlohmann/json.hpp>
using nlohmann::json;
using json = nlohmann::json;
int main()
{
@@ -72,7 +72,7 @@ The default value is `0` (disabled, the deprecated functions can still be called
#define JSON_DELETE_DEPRECATED_FUNCTIONS 1
#include <nlohmann/json.hpp>
using nlohmann::json;
using json = nlohmann::json;
int main()
{
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