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Author SHA1 Message Date
Niels Lohmann 2a56afc714 Fix VS 2015 build of the DOM parser (#5882) (#5916)
- Name std::hash only once the object type has emplace_new_key: VS 2015
  static-asserts on std::hash of a type without one (alt_string) instead of
  reporting a substitution failure (C2338).
- Replace the std::copy calls on frames by loops: VS 2015 reports raw
  pointers handed to std::copy as C4996, an error under /WX.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 12:08:58 +01:00
Niels Lohmann d176d8d61e Exclude single_include from flawfinder scan (#5912)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 12:08:36 +01:00
Niels Lohmann 1cf5492bcd docs: byte layout sections, glossary entries, and QA page update (#5910)
* docs: byte layout sections, glossary, and QA page updates

- Move "Byte layout" of each binary format to its own section before
  "Serialization" and describe the idea of the format.
- Glossary: add LLDB and other terms used throughout the documentation.
- quality_assurance: correct Clang Static Analyzer and CMake entries; add
  CodeQL, Semgrep, Flawfinder, CIFuzz, OpenSSF Scorecard, REUSE, Meson/SwiftPM,
  and reproducibility checks.

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

* docs: drop unused length colour from CBOR and MessagePack byte layout legends

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 12:08:14 +01:00
Niels Lohmann 330fbead59 Document clang-tidy exclusions, drop unneeded ones, and clean up doc examples (#5909)
* Document clang-tidy exclusions and drop unneeded ones

Re-enable every excluded check in a run of clang-tidy 22 over all tests
and remove the seven that never fire (cert-err58-cpp,
clang-analyzer-webkit.NoUncountedMemberChecker,
cppcoreguidelines-virtual-class-destructor, google-readability-function-size,
hicpp-function-size, hicpp-no-assembler, readability-function-size).

Document the reason for every remaining exclusion at the top of the file.

Exclude in advance the checks that only exist in clang-tidy 23 and are
noise here (bugprone-signed-bitwise, *-explicit-constructor,
readability-trailing-comma, modernize-use-string-view), plus
modernize-use-integer-sign-comparison, which needs C++20 std::cmp_less
and flags deliberate casts.

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

* Fix clang-tidy findings in documentation examples and replace redundant aliases

Apply clang-tidy fixes to the documentation examples:
- performance-avoid-endl: std::endl -> '\n'
- readability-qualified-auto: auto -> auto* / const auto*
- performance-for-range-copy: copy -> const reference
- google-readability-casting: C-style cast -> static_cast

Replace redundant aliases (readability-redundant-qualified-alias) such as
"using json = nlohmann::json;" with "using nlohmann::json;" in the
documentation, README, examples, tests, and benchmarks. Aliases at class
scope and aliases of other types (with_base_class_t etc.) are kept.

No changes to the library or its public API. All changed examples were
compiled and run; their output matches the stored .output files (except
max_size and meta, which depend on the platform and compiler).

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

* Format doc examples with the pinned astyle

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 12:07:51 +01:00
Niels Lohmann fe231dc692 docs: write std::chrono durations as unit/value objects; reword a title with escaped quotes (#5911)
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 12:07:32 +01:00
Niels Lohmann ffd4242dc2 Docs: fill documentation gaps found in user questions (#5907)
* Docs: fill documentation gaps found in user questions

Add pages on class-hierarchy/smart-pointer/variant/chrono recipes, working
without exceptions, and large, streamed and partial input. Extend the FAQ
(23 entries, Known bugs first), parse error documentation (empty-input
checklist, line/column, diagnostic positions), element access, conversions,
creating values, ADL troubleshooting, memory, and build/distribution notes.
Add 14 examples with generated output. Correct the statement that parse errors
cannot be recovered from with -fno-exceptions.

The topics come from recurring questions on Stack Overflow, Reddit, Hacker
News, YouTube, and the project's GitHub discussions and issues.

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

* docs: declare range-for lists in variables to keep astyle quiet

astyle reformats a braced init list placed directly in a range-for
header; declare the list first so check_amalgamation passes.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-25 12:07:13 +01:00
490 changed files with 7075 additions and 3351 deletions

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+36 -7
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@@ -1,3 +1,33 @@
# 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.
@@ -10,14 +40,14 @@ Checks: '*,
-android-cloexec-fopen,
-boost-use-ranges,
-bugprone-easily-swappable-parameters,
-cert-err58-cpp,
-clang-analyzer-webkit.NoUncountedMemberChecker,
-bugprone-signed-bitwise,
-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,
@@ -26,19 +56,15 @@ 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,
@@ -48,6 +74,7 @@ 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,
@@ -55,20 +82,22 @@ 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'
+3 -3
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@@ -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
+2 -1
View File
@@ -43,7 +43,8 @@ jobs:
- name: flawfinder_scan
uses: david-a-wheeler/flawfinder@c4216b74cf2639ffa98503768bd6e4299b5440c9 # v2.0.20
with:
arguments: '--sarif ./'
# single_include/ is omitted: it is generated from include/ and would report every finding twice
arguments: '--sarif ./cmake ./docs ./include ./src ./tests ./tools'
output: 'flawfinder_results.sarif'
- name: Upload analysis results to GitHub Security tab
-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 json = nlohmann::json;
using nlohmann::json;
// ...
@@ -164,7 +164,7 @@ If using modules (enabled with `NLOHMANN_JSON_BUILD_MODULES`), this example beco
import std;
import nlohmann.json;
using json = nlohmann::json;
using 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 json = nlohmann::json;
using 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 json = nlohmann::json;
using 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 -1
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@@ -45,7 +45,7 @@ Constant.
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -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
@@ -3,7 +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_document;
```
@@ -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
@@ -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
@@ -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`.
+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.
@@ -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`
-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.
@@ -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
+1 -1
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
+2
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
+2 -2
View File
@@ -38,7 +38,7 @@ Therefore, assertions can be switched off by defining `NDEBUG`.
```cpp
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -64,7 +64,7 @@ Therefore, assertions can be switched off by defining `NDEBUG`.
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -79,7 +79,7 @@ The default value is `0` (disabled — existing behavior is preserved).
```cpp
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using 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 json = nlohmann::json;
using 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 json = nlohmann::json;
using 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 json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -39,7 +39,7 @@ The default value is `0`.
#define JSON_DISABLE_ENUM_SERIALIZATION 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
enum class Choice
{
@@ -66,7 +66,7 @@ The default value is `0`.
#define JSON_DISABLE_ENUM_SERIALIZATION 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
enum class Choice
{
@@ -99,7 +99,7 @@ The default value is `0`.
#define JSON_DISABLE_ENUM_SERIALIZATION 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
enum class Choice
{
@@ -92,7 +92,7 @@ The default value is `0`: streams are scanned in bulk.
#include <sstream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -115,7 +115,7 @@ The default value is `0`: streams are scanned in bulk.
#include <sstream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -72,7 +72,7 @@ The default value is `0` (disabled — existing behavior is preserved).
```cpp
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -89,7 +89,7 @@ The default value is `0` (disabled — existing behavior is preserved).
#define JSON_DISABLE_TUPLE_REFERENCE_CONVERSION 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -73,7 +73,7 @@ The default value is `0`: the file is locked once and read with the unlocked std
#include <cstdio>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -92,7 +92,7 @@ The default value is `0`: the file is locked once and read with the unlocked std
#include <cstdio>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
+2 -4
View File
@@ -5,8 +5,7 @@
```
When defined, the library uses only portable C++ code where it would otherwise use vector instructions: when scanning
strings during parsing, and when writing floating-point numbers during serialization. This includes the parser of
[`basic_json_document`](../basic_json_document/index.md) (`<nlohmann/json_view.hpp>`).
strings during parsing, and when writing floating-point numbers during serialization.
The macro is an escape hatch, for example for toolchains that cannot compile the vector code, for sanitizers or
analyzers that do not understand it, or to compare the speed of both variants. It does not change any result: values,
@@ -62,7 +61,7 @@ By default, `#!cpp JSON_NO_SIMD` is not defined, and vector instructions are use
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -78,7 +77,6 @@ By default, `#!cpp JSON_NO_SIMD` is not defined, and vector instructions are use
- [**JSON_USE_SIMDUTF**](json_use_simdutf.md) - use the simdutf library to accelerate UTF-8 validation
- [**JSON_DISABLE_STREAM_BULK_SCAN**](json_disable_stream_bulk_scan.md) - read a `std::istream` one character at a time
- [Parsing: input sources and performance](../../features/parsing/index.md#input-sources-and-performance)
- [json_view](../../features/json_view.md) - the zero-copy view, whose parser the macro also affects
## Version history
@@ -94,7 +94,7 @@ The default value is `0` (disabled — existing behavior is preserved).
#include <sstream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -115,7 +115,7 @@ The default value is `0` (disabled — existing behavior is preserved).
#include <sstream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -64,7 +64,7 @@ The default value is `0` (disabled, the behavior of version 3.12.0 and earlier i
```cpp
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -81,7 +81,7 @@ The default value is `0` (disabled, the behavior of version 3.12.0 and earlier i
#define JSON_STRICT_BINARY_UTF8 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -92,7 +92,7 @@ The default value is `0` (disabled — existing behavior is preserved).
```cpp
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -109,7 +109,7 @@ The default value is `0` (disabled — existing behavior is preserved).
#define JSON_STRICT_NUL_HANDLING 1
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -77,7 +77,7 @@ The default value is `0` (disabled — existing behavior is preserved).
#include <map>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
enum TaskState { TS_STOPPED, TS_RUNNING, TS_COMPLETED };
@@ -105,7 +105,7 @@ The default value is `0` (disabled — existing behavior is preserved).
#include <map>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
enum TaskState { TS_STOPPED, TS_RUNNING, TS_COMPLETED };
@@ -0,0 +1,52 @@
# JSON_VIEW_NO_SIMD
```cpp
#define JSON_VIEW_NO_SIMD
```
When defined, the parser of [`basic_json_document`](../basic_json_document/index.md) (`<nlohmann/json_view.hpp>`)
uses only portable C++ to scan strings. By default, it scans long runs of string bytes 16 at a time with NEON on
AArch64 (with GCC and Clang) and SSE2 on x86-64, which are part of the baseline instruction sets of these
architectures, and validates non-ASCII text with NEON (or SSSE3, see
[`JSON_VIEW_USE_SSSE3`](json_view_use_ssse3.md)).
The same input is accepted or rejected either way, with the same values, and errors are reported the same way; only
the speed differs. The macro exists for platforms whose compilers lack the intrinsics headers, and to test the portable
code.
!!! note "ABI compatibility"
The macro selects between two definitions of the same inline functions. Whether it is defined is encoded in the
[namespace](../../features/namespace.md) (tag `_vns`), resulting in distinct symbol names. Translation units
compiled with and without it can therefore be linked into the same program without One Definition Rule (ODR)
violations, but they cannot exchange instances of library types.
## Default definition
By default, `#!cpp JSON_VIEW_NO_SIMD` is not defined, and the vector code is used where available.
```cpp
#undef JSON_VIEW_NO_SIMD
```
## Examples
??? example
The code below uses the portable string scanning of the view.
```cpp
#define JSON_VIEW_NO_SIMD
#include <nlohmann/json_view.hpp>
...
```
## See also
- [JSON_VIEW_USE_SSSE3](json_view_use_ssse3.md) - validate non-ASCII strings with SSSE3 on x86-64
- [json_view](../../features/json_view.md) - the zero-copy view
## Version history
- Added in version 3.13.0.
@@ -0,0 +1,53 @@
# JSON_VIEW_USE_SSSE3
```cpp
#define JSON_VIEW_USE_SSSE3
```
When defined on x86-64, the parser of [`basic_json_document`](../basic_json_document/index.md)
(`<nlohmann/json_view.hpp>`) validates non-ASCII text in strings with SSSE3 without asking the CPU first.
By default, the parser checks once at run time whether the CPU has SSSE3 (all x86-64 CPUs since about 2011 have it)
and then validates non-ASCII text 16 bytes at a time, using the "lookup4" algorithm of
[simdjson](https://github.com/simdjson/simdjson); on CPUs without SSSE3, it validates one UTF-8 sequence at a time.
The vector check is compiled for SSSE3 with a function attribute (GCC 4.9 and later, Clang), so this needs no compiler
option. With MSVC, the check uses `__cpuid`. On AArch64, the vector check uses NEON and is always on.
Define the macro only together with a compiler option that enables SSSE3 (e.g. `-mssse3`, or `-march=` with a CPU that
has it), and only for programs that run on such CPUs. It saves the check of the CPU, which costs little. The same
input is accepted or rejected either way; only the speed of non-ASCII text differs.
!!! note "ABI compatibility"
The macro selects between two definitions of the same inline functions. Whether it is defined is encoded in the
[namespace](../../features/namespace.md) (tag `_vssse3`, on every architecture), resulting in distinct symbol
names. Translation units compiled with and without it can therefore be linked into the same program without One
Definition Rule (ODR) violations, but they cannot exchange instances of library types.
## Default definition
By default, `#!cpp JSON_VIEW_USE_SSSE3` is not defined.
```cpp
#undef JSON_VIEW_USE_SSSE3
```
## Examples
??? example
With CMake, for a program that only runs on CPUs with SSSE3:
```cmake
target_compile_definitions(your_target PRIVATE JSON_VIEW_USE_SSSE3)
target_compile_options(your_target PRIVATE -mssse3)
```
## See also
- [JSON_VIEW_NO_SIMD](json_view_no_simd.md) - use only portable code in the view's parser
- [JSON_USE_SIMDUTF](json_use_simdutf.md) - validate UTF-8 with simdutf in `basic_json`'s parser
## Version history
- Added in version 3.13.0.
@@ -147,13 +147,6 @@ void to_json(BasicJsonType& j, const B& b) {
See Implementation limits for [NLOHMANN_DEFINE_TYPE_INTRUSIVE](nlohmann_define_type_intrusive.md) and
[NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE](nlohmann_define_type_non_intrusive.md), respectively.
!!! info "Views"
The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
(`<nlohmann/json_view.hpp>`): [`get<T>()`](../basic_json_view/get.md) on a view looks the members up in the
view, without building a `json` value first. The base part is read from the view as well if the base's
`from_json()` accepts views, and from [`materialize()`](../basic_json_view/materialize.md) otherwise.
## Examples
??? example "Example: (1) NLOHMANN_DEFINE_DERIVED_TYPE_INTRUSIVE"
@@ -199,5 +192,3 @@ void to_json(BasicJsonType& j, const B& b) {
6. Added in version 3.12.0.
All six macros were changed to allow an empty member list in version 3.13.0.
The generated `from_json()` reads the views of `json_document`s since version 3.13.0.
@@ -81,12 +81,6 @@ See the examples below for the concrete generated code.
that serializes a struct's members positionally into a JSON array; for that, write `to_json`/`from_json` by
hand, building/reading a `json::array()` of the members in order.
!!! info "Views"
The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
(`<nlohmann/json_view.hpp>`): [`get<T>()`](../basic_json_view/get.md) on a view looks the members up in the
view, without building a `json` value first.
## Examples
??? example "Example: (1) NLOHMANN_DEFINE_TYPE_INTRUSIVE"
@@ -195,5 +189,3 @@ See the examples below for the concrete generated code.
All three macros were changed to work with any `basic_json` specialization (not only `nlohmann::json`) in version 3.12.0,
and to allow an empty member list in version 3.13.0.
The generated `from_json()` reads the views of `json_document`s since version 3.13.0.
@@ -80,12 +80,6 @@ See the examples below for the concrete generated code.
that serializes a struct's members positionally into a JSON array; for that, write `to_json`/`from_json` by
hand, building/reading a `json::array()` of the members in order.
!!! info "Views"
The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
(`<nlohmann/json_view.hpp>`): [`get<T>()`](../basic_json_view/get.md) on a view looks the members up in the
view, without building a `json` value first.
## Examples
??? example "Example: (1) NLOHMANN_DEFINE_TYPE_NON_INTRUSIVE"
@@ -194,5 +188,3 @@ See the examples below for the concrete generated code.
All three macros were changed to work with any `basic_json` specialization (not only `nlohmann::json`) in version 3.12.0,
and to allow an empty member list in version 3.13.0.
The generated `from_json()` reads the views of `json_document`s since version 3.13.0.
@@ -39,6 +39,6 @@ the library.
## Version history
- Added in version 3.11.0. Changed inline namespace name in version 3.11.2. Added the ABI tag `_dp` in
version 3.12.0, and the ABI tags `_bics`, `_psp`, `_snul`, `_sbu8`, `_ekmo`, `_dsbs`, `_dufio`, and `_ns` in
version 3.13.0; see
version 3.12.0, and the ABI tags `_bics`, `_psp`, `_snul`, `_sbu8`, `_ekmo`, `_dsbs`, `_dufio`, `_ns`, `_vns`,
and `_vssse3` in version 3.13.0; see
[`nlohmann` Namespace](../../features/namespace.md#structure).
@@ -45,12 +45,6 @@ inline void from_json(const BasicJsonType& j, type& e);
Define [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](json_use_objects_for_enum_keyed_maps.md) to store them as objects
with the converted keys. Such maps can be read from both forms.
!!! info "Views"
The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
(`<nlohmann/json_view.hpp>`), comparing the view with the entries of the mapping, without building a `json` value
first.
## Examples
??? example "Example: Basic usage"
@@ -94,5 +88,3 @@ inline void from_json(const BasicJsonType& j, type& e);
## Version history
Added in version 3.4.0.
The generated `from_json()` reads the views of `json_document`s since version 3.13.0.
@@ -48,12 +48,6 @@ inline void from_json(const BasicJsonType& j, type& e);
Define [`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](json_use_objects_for_enum_keyed_maps.md) to store them as objects
with the converted keys. Such maps can be read from both forms.
!!! info "Views"
The generated `from_json()` also reads the views of [`json_document`](../json_document.md)s
(`<nlohmann/json_view.hpp>`), comparing the view with the entries of the mapping, without building a `json` value
first.
## Examples
??? example "Example: Basic usage"
@@ -3,7 +3,7 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using ordered_json_editable_document = basic_json_document<ordered_json, view_mode::editable>;
using ordered_json_editable_document = basic_json_document<ordered_json, true>;
```
This type is an **editable** [`basic_json_document`](basic_json_document/index.md) of the
@@ -3,7 +3,7 @@
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using ordered_json_editable_view = basic_json_view<ordered_json, view_mode::editable>;
using ordered_json_editable_view = basic_json_view<ordered_json, true>;
```
This type is a [`basic_json_view`](basic_json_view/index.md) of a value of an
-81
View File
@@ -1,81 +0,0 @@
# <small>nlohmann::</small>view_mode
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
enum class view_mode : std::uint8_t
{
read_only,
editable
};
```
The second template parameter of [`basic_json_document`](basic_json_document/index.md) and
[`basic_json_view`](basic_json_view/index.md): whether a document can be changed after parsing, and whether a view is
of such a document.
`read_only`
: the default: the document is parsed once and then only read. It carries none of the bookkeeping edits need, and
calling [`set`](basic_json_document/set.md), [`push_back`](basic_json_document/push_back.md),
[`insert`](basic_json_document/insert.md), or [`erase`](basic_json_document/erase.md) on it fails to compile.
`editable`
: the document also offers [`set`](basic_json_document/set.md), [`push_back`](basic_json_document/push_back.md),
[`insert`](basic_json_document/insert.md), and [`erase`](basic_json_document/erase.md); its views see every edit,
see [Edits](basic_json_document/index.md#edits).
The shortcuts name both modes: [`json_document`](json_document.md) and [`json_view`](json_view.md) are read-only,
[`json_editable_document`](json_editable_document.md) and [`json_editable_view`](json_editable_view.md) are editable
(and likewise for `ordered_json`).
## Notes
The mode is part of the view's type, and there is no conversion between the two modes: a read-only view reads a
container in place, while a view of an editable document follows the links that edits leave behind. A function that
accepts views therefore names the modes it accepts in its signature:
```cpp
// views of editable documents only
template<typename BasicJsonType>
void f(basic_json_view<BasicJsonType, view_mode::editable> v);
// views of read-only documents only
template<typename BasicJsonType>
void f(basic_json_view<BasicJsonType, view_mode::read_only> v);
// either
template<typename BasicJsonType, view_mode Mode>
void f(basic_json_view<BasicJsonType, Mode> v);
```
A function that takes a [`json_view`](json_view.md) accepts neither an [`ordered_json_view`](ordered_json_view.md)
nor a [`json_editable_view`](json_editable_view.md). Views of the two modes still compare with
[`operator==`](basic_json_view/operator_eq.md).
## Examples
??? example
The example below shows a function template that accepts the views of both modes, and one that accepts only
views of editable documents.
```cpp
--8<-- "examples/view_mode.cpp"
```
Output:
```
--8<-- "examples/view_mode.output"
```
## See also
- [basic_json_document](basic_json_document/index.md) - a parsed JSON text
- [basic_json_view](basic_json_view/index.md) - a handle to one value of a document
- [json_editable_document](json_editable_document.md) - an editable document of `json`
- [Writing generic code](../features/json_view.md#writing-generic-code) - functions that accept views
## Version history
Added in version 3.13.0.
@@ -188,10 +188,13 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
```
- [x] The code is checked with the latest [Cppcheck](https://cppcheck.sourceforge.io) with all warnings enabled.
- [x] The code is checked with the latest [Clang Static Analyzer](https://clang-analyzer.llvm.org) with 89 enabled
rules.
- [x] The code is checked with the latest [Clang Static Analyzer](https://clang-analyzer.llvm.org) with 52 enabled
checkers.
- [x] The code is checked with [Infer](https://fbinfer.com).
- [x] The code is checked with [Codacy](https://app.codacy.com/gh/nlohmann/json/dashboard).
- [x] The code is scanned with [CodeQL](https://codeql.github.com), [Semgrep](https://semgrep.dev), and
[Flawfinder](https://dwheeler.com/flawfinder/) on every push and pull request and on a schedule; the findings are
reported to GitHub's code scanning.
## Dynamic analysis
@@ -204,6 +207,8 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
- [x] The test suite is executed with [Valgrind](https://valgrind.org) (Memcheck) to detect memory leaks.
- [x] The test suite is executed with [Sanitizers](https://github.com/google/sanitizers) (address sanitizer, undefined
behavior sanitizer, integer overflow detection, nullability violations).
- [x] The fuzz targets are run with [CIFuzz](https://google.github.io/oss-fuzz/getting-started/continuous-integration/)
on every pull request to catch regressions before they are merged.
## Dependencies
@@ -223,6 +228,8 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
No release is made while such an alert is open.
- [x] Third-party code included in the repository for testing, such as [doctest](https://github.com/doctest/doctest),
is updated manually.
- [x] The repository is evaluated with the [OpenSSF Scorecard](https://securityscorecards.dev) on a schedule and on
every push to the default branch, and the results are reported to GitHub's code scanning.
## Style check
@@ -258,4 +265,21 @@ Note: Some modern features (like C++20 ranges or filesystem support) may be disa
- [x] The library is tested against relevant CMake versions:
- CMake 3.5 (the earliest supported)
- CMake 3.31.6 (the latest 3.x release)
- CMake 4.0.0 (a very recent release)
- CMake 4.0.0 (the first 4.x release)
!!! success "Requirement: Other build systems"
The library can be used with build systems and package managers other than CMake.
- [x] The library can be consumed with [Meson](https://json.nlohmann.me/integration/package_managers/) and the Swift
Package Manager; the installation with Meson and the resolution of `Package.swift` are tested in the CI.
!!! success "Requirement: Reproducible and verifiable builds"
The library can be built and tested without network access or a Git checkout, and its licensing is machine-readable.
- [x] The test suite is executed from an exported source tree without the `.git` directory and with the test data
being available offline.
- [x] The test suite is executed without the tests that change installed files to check that builds are reproducible.
- [x] The repository is checked for compliance with the [REUSE specification](https://reuse.software) so that the
license and copyright of every file is machine-readable.
- [x] The documentation is built with warnings treated as errors, and its links are checked regularly.
+1 -1
View File
@@ -2,7 +2,7 @@
#include <iomanip>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -2,7 +2,7 @@
#include <vector>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
+3 -3
View File
@@ -2,19 +2,19 @@
#include <iomanip>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
// a valid JSON text
auto valid_text = R"(
const auto* valid_text = R"(
{
"numbers": [1, 2, 3]
}
)";
// an invalid JSON text
auto invalid_text = R"(
const auto* invalid_text = R"(
{
"strings": ["extra", "comma", ]
}
@@ -2,7 +2,7 @@
#include <string>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
+1 -1
View File
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
+2 -2
View File
@@ -2,9 +2,9 @@
#include <iomanip>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
std::cout << std::boolalpha << std::is_same<std::vector<json>, json::array_t>::value << std::endl;
std::cout << std::boolalpha << std::is_same<std::vector<json>, json::array_t>::value << '\n';
}
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
using namespace nlohmann::literals;
int main()
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
using namespace nlohmann::literals;
int main()
@@ -3,7 +3,7 @@
#include <nlohmann/json.hpp>
using namespace std::string_view_literals;
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -3,7 +3,7 @@
#include <nlohmann/json.hpp>
using namespace std::string_view_literals;
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
+1 -1
View File
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
+1 -1
View File
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,8 +1,8 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using ordered_json = nlohmann::ordered_json;
using nlohmann::json;
using nlohmann::ordered_json;
int main()
{
@@ -8,7 +8,7 @@
#include <valarray>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json.hpp>
using json = nlohmann::json;
using nlohmann::json;
int main()
{
@@ -2,7 +2,7 @@
#include <nlohmann/json.hpp>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -2,7 +2,7 @@
#include <utility>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,9 +1,9 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json = nlohmann::json;
using json_editable_document = nlohmann::json_editable_document;
using json_editable_view = nlohmann::json_editable_view;
using nlohmann::json;
using nlohmann::json_editable_document;
using nlohmann::json_editable_view;
int main()
{
@@ -1,9 +1,9 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json = nlohmann::json;
using json_editable_document = nlohmann::json_editable_document;
using json_editable_view = nlohmann::json_editable_view;
using nlohmann::json;
using nlohmann::json_editable_document;
using nlohmann::json_editable_view;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -4,8 +4,8 @@
#include <vector>
#include <nlohmann/json_view.hpp>
using json = nlohmann::json;
using json_document = nlohmann::json_document;
using nlohmann::json;
using nlohmann::json_document;
using image_check = json_document::image_check;
int main()
@@ -2,7 +2,7 @@
#include <string>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -2,7 +2,7 @@
#include <string>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -3,7 +3,7 @@
#include <nlohmann/json.hpp>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
json_document parse_from_temporary_buffer()
{
@@ -2,7 +2,7 @@
#include <vector>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,8 +1,8 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json = nlohmann::json;
using json_editable_document = nlohmann::json_editable_document;
using nlohmann::json;
using nlohmann::json_editable_document;
int main()
{
@@ -3,7 +3,7 @@
#include <vector>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -4,7 +4,7 @@
#include <vector>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,9 +1,9 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json = nlohmann::json;
using json_editable_document = nlohmann::json_editable_document;
using json_editable_view = nlohmann::json_editable_view;
using nlohmann::json;
using nlohmann::json_editable_document;
using nlohmann::json_editable_view;
int main()
{
@@ -3,7 +3,7 @@
#include <string>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -2,7 +2,7 @@
#include <string>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,8 +1,8 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using json_view = nlohmann::json_view;
using nlohmann::json_document;
using nlohmann::json_view;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
using json_pointer = nlohmann::json::json_pointer;
int main()
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -2,8 +2,8 @@
#include <numeric>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using json_view = nlohmann::json_view;
using nlohmann::json_document;
using nlohmann::json_view;
int main()
{
@@ -2,8 +2,8 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using json_view = nlohmann::json_view;
using nlohmann::json_document;
using nlohmann::json_view;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
using json_pointer = nlohmann::json::json_pointer;
int main()
@@ -1,7 +1,7 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using nlohmann::json_document;
int main()
{
@@ -1,8 +1,8 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
using json_view = nlohmann::json_view;
using nlohmann::json_document;
using nlohmann::json_view;
int main()
{
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