mirror of
https://github.com/nlohmann/json.git
synced 2026-10-23 06:18:56 +00:00
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No files matched your search
@@ -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
|
||||
|
||||
|
||||
@@ -18,7 +18,8 @@ environment:
|
||||
matrix:
|
||||
# The Visual Studio 2017 jobs compile everything with /std:c++17, so they
|
||||
# only build the C++17 variant of each test, split into two jobs each to
|
||||
# stay below AppVeyor's 60-minute limit per job.
|
||||
# stay below AppVeyor's 60-minute limit per job. The Visual Studio 2019
|
||||
# job builds the tests for all standards and is split for the same reason.
|
||||
- APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
|
||||
configuration: Debug
|
||||
platform: x86
|
||||
@@ -50,7 +51,13 @@ environment:
|
||||
configuration: Release
|
||||
platform: x86
|
||||
CXX_FLAGS: "/W4 /WX"
|
||||
CMAKE_OPTIONS: "-DJSON_ImplicitConversions=OFF"
|
||||
CMAKE_OPTIONS: "-DJSON_ImplicitConversions=OFF -DJSON_TestShard=0/2"
|
||||
GENERATOR: Visual Studio 16 2019
|
||||
- APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2019
|
||||
configuration: Release
|
||||
platform: x86
|
||||
CXX_FLAGS: "/W4 /WX"
|
||||
CMAKE_OPTIONS: "-DJSON_ImplicitConversions=OFF -DJSON_TestShard=1/2"
|
||||
GENERATOR: Visual Studio 16 2019
|
||||
|
||||
- APPVEYOR_BUILD_WORKER_IMAGE: Visual Studio 2015
|
||||
|
||||
@@ -64,6 +64,7 @@ labels:
|
||||
- "tests/src/unit-json_view.*"
|
||||
- "tests/src/json_view_test_helpers\\.hpp"
|
||||
- "tests/src/fuzzer-(parse_json_view|json_view_image)\\.cpp"
|
||||
- "tests/benchmarks/json_view/.*"
|
||||
- "tools/amalgamate/config_json_view\\.json"
|
||||
- "docs/mkdocs/docs/features/json_view\\.md"
|
||||
- "docs/mkdocs/docs/api/basic_json_(document|view)/.*"
|
||||
|
||||
@@ -0,0 +1 @@
|
||||
meson==1.12.1
|
||||
@@ -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
|
||||
@@ -0,0 +1 @@
|
||||
semgrep==1.168.0
|
||||
File diff suppressed because it is too large.
Load diff
@@ -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: |
|
||||
@@ -154,6 +154,28 @@ jobs:
|
||||
# PR content in a job without credentials.
|
||||
python3 tools/generate_natvis/generate_natvis.py $MAIN_DIR
|
||||
|
||||
- name: Check the nlohmann_json.natvis generator options
|
||||
run: |
|
||||
cd $MAIN_DIR
|
||||
# The options for configurations outside the checked-in file write
|
||||
# to a temporary file, so they do not affect the diff below.
|
||||
GENERATOR=tools/generate_natvis/generate_natvis.py
|
||||
python3 $GENERATOR --list-tags
|
||||
TAG_COUNT=$(python3 $GENERATOR --list-tags | wc -l)
|
||||
|
||||
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
|
||||
test $(grep -c '<!-- Namespace ' $RUNNER_TEMP/all.natvis) -eq $(( (1 << TAG_COUNT) * 2 + 1 ))
|
||||
|
||||
if python3 $GENERATOR --abi-tags _unknown --output $RUNNER_TEMP/unknown.natvis; then
|
||||
echo "generate_natvis.py accepted an unknown ABI tag"
|
||||
exit 1
|
||||
fi
|
||||
|
||||
- name: Build patch and check for differences
|
||||
id: diff
|
||||
run: |
|
||||
|
||||
@@ -1,81 +0,0 @@
|
||||
name: "Check API documentation"
|
||||
|
||||
on:
|
||||
pull_request:
|
||||
|
||||
permissions:
|
||||
contents: read
|
||||
|
||||
jobs:
|
||||
check_api_docs:
|
||||
runs-on: ubuntu-latest
|
||||
|
||||
steps:
|
||||
- name: Harden Runner
|
||||
uses: step-security/harden-runner@bf7454d06d71f1098171f2acdf0cd4708d7b5920 # v2.20.0
|
||||
with:
|
||||
egress-policy: audit
|
||||
|
||||
- name: Checkout pull request
|
||||
uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
|
||||
|
||||
- name: Install clang
|
||||
# Used only as a subprocess for `clang++ -E -v` system-include-path discovery in
|
||||
# extract_api.py; it does not need to version-match the pinned libclang pip wheel
|
||||
# below, which does the actual AST parsing. Do not "fix" this to be version-matched.
|
||||
run: sudo apt-get update && sudo apt-get install -y clang
|
||||
|
||||
- name: Install Python dependencies
|
||||
run: pip install -r tools/api_checker/requirements.txt
|
||||
|
||||
- name: Extract API and regenerate the committed surface file
|
||||
run: |
|
||||
python3 tools/api_checker/extract_api.py \
|
||||
--header include/nlohmann/json.hpp \
|
||||
--include include \
|
||||
--output /tmp/api_snapshot.json \
|
||||
--surface-output tools/api_checker/api_surface.json
|
||||
|
||||
- name: "Check API documentation (Phase 1: advisory)"
|
||||
# Surfaces missing/broken @sa links without failing the job while the backlog from the
|
||||
# initial AST-based rollout is burned down. See tools/api_checker/POLICY.md and the PR
|
||||
# that introduced this workflow for the two-phase rollout plan.
|
||||
continue-on-error: true
|
||||
run: |
|
||||
python3 tools/api_checker/check_docs.py \
|
||||
--snapshot /tmp/api_snapshot.json
|
||||
|
||||
- name: Check macro documentation (advisory only)
|
||||
# Cross-checks docs/mkdocs/docs/api/macros/ pages against #define sites. Only checks the
|
||||
# documented-macro-still-exists direction; never blocks CI. See POLICY.md.
|
||||
run: python3 tools/api_checker/check_macros.py
|
||||
|
||||
- name: Check for uncommitted API surface changes
|
||||
id: diff
|
||||
run: |
|
||||
mkdir -p ${{ github.workspace }}/patch
|
||||
git diff --patch --no-color -- tools/api_checker/api_surface.json > ${{ github.workspace }}/patch/api_surface.patch
|
||||
if [ -s ${{ github.workspace }}/patch/api_surface.patch ]; then
|
||||
echo "tools/api_checker/api_surface.json is out of date. Diff:"
|
||||
cat ${{ github.workspace }}/patch/api_surface.patch
|
||||
echo "has_diff=true" >> "$GITHUB_OUTPUT"
|
||||
else
|
||||
echo "has_diff=false" >> "$GITHUB_OUTPUT"
|
||||
fi
|
||||
|
||||
# Uploaded so contributors can fix their PR with `git apply api_surface.patch`
|
||||
# instead of installing libclang locally.
|
||||
- name: Upload patch
|
||||
if: steps.diff.outputs.has_diff == 'true'
|
||||
uses: actions/upload-artifact@043fb46d1a93c77aae656e7c1c64a875d1fc6a0a # v7.0.1
|
||||
with:
|
||||
name: api-surface-patch
|
||||
path: patch/api_surface.patch
|
||||
|
||||
- name: Fail if API surface file is not up to date
|
||||
# Unlike the doc-backlog check above, this is purely mechanical regeneration with no
|
||||
# backlog to phase in -- blocking from the start, matching check_amalgamation.yml's
|
||||
# precedent. Contributors who add/remove/rename public API must regenerate and commit
|
||||
# tools/api_checker/api_surface.json as part of their PR.
|
||||
if: steps.diff.outputs.has_diff == 'true'
|
||||
run: exit 1
|
||||
@@ -38,14 +38,14 @@ jobs:
|
||||
|
||||
# Initializes the CodeQL tools for scanning.
|
||||
- name: Initialize CodeQL
|
||||
uses: github/codeql-action/init@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
|
||||
uses: github/codeql-action/init@6f2ac81f5cd81fe351a197ba0b00d91d03cd2aee # v4.39.0
|
||||
with:
|
||||
languages: c-cpp
|
||||
|
||||
# Autobuild attempts to build any compiled languages (C/C++, C#, or Java).
|
||||
# If this step fails, then you should remove it and run the build manually (see below)
|
||||
- name: Autobuild
|
||||
uses: github/codeql-action/autobuild@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
|
||||
uses: github/codeql-action/autobuild@6f2ac81f5cd81fe351a197ba0b00d91d03cd2aee # v4.39.0
|
||||
|
||||
- name: Perform CodeQL Analysis
|
||||
uses: github/codeql-action/analyze@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
|
||||
uses: github/codeql-action/analyze@6f2ac81f5cd81fe351a197ba0b00d91d03cd2aee # v4.39.0
|
||||
@@ -37,6 +37,14 @@ jobs:
|
||||
var matchArtifact = artifacts.data.artifacts.filter((artifact) => {
|
||||
return artifact.name == "pr"
|
||||
})[0];
|
||||
// a run that failed before its jobs started (e.g. a stale queued
|
||||
// run cancelled long after its push) has no artifact to report on
|
||||
if (!matchArtifact) {
|
||||
core.notice('Run ${{ github.event.workflow_run.id }} has no "pr" artifact; nothing to comment on.');
|
||||
core.setOutput('found', 'false');
|
||||
return;
|
||||
}
|
||||
core.setOutput('found', 'true');
|
||||
var download = await github.rest.actions.downloadArtifact({
|
||||
owner: context.repo.owner,
|
||||
repo: context.repo.repo,
|
||||
@@ -51,9 +59,11 @@ jobs:
|
||||
# Extract the untrusted PR artifact into a dedicated empty directory and
|
||||
# read only the two expected files by fixed path afterwards. This avoids a
|
||||
# malicious archive overwriting workspace files or escaping via ../ paths.
|
||||
- run: unzip -o pr.zip -d ./pr_artifact
|
||||
- if: steps.download.outputs.found == 'true'
|
||||
run: unzip -o pr.zip -d ./pr_artifact
|
||||
|
||||
- name: 'Comment on PR'
|
||||
if: steps.download.outputs.found == 'true'
|
||||
uses: actions/github-script@3a2844b7e9c422d3c10d287c895573f7108da1b3 # v9.0.0
|
||||
with:
|
||||
github-token: ${{ secrets.GITHUB_TOKEN }}
|
||||
|
||||
@@ -47,6 +47,6 @@ jobs:
|
||||
output: 'flawfinder_results.sarif'
|
||||
|
||||
- name: Upload analysis results to GitHub Security tab
|
||||
uses: github/codeql-action/upload-sarif@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
|
||||
uses: github/codeql-action/upload-sarif@6f2ac81f5cd81fe351a197ba0b00d91d03cd2aee # v4.39.0
|
||||
with:
|
||||
sarif_file: ${{github.workspace}}/flawfinder_results.sarif
|
||||
@@ -0,0 +1,84 @@
|
||||
name: "json_view benchmarks"
|
||||
|
||||
# On demand only: runs the comparison of json_view with yyjson, simdjson, and
|
||||
# Boost.JSON (tests/benchmarks/json_view/compare.py) on GitHub-hosted runners,
|
||||
# for numbers from x86-64 and AArch64 Linux. It runs when started by hand, or
|
||||
# when a pull request gets the label "benchmark" (on both architectures, with
|
||||
# GCC and the default settings). Shared runners are noisy: the results show
|
||||
# where json_view stands, but published numbers need a quiet machine (see
|
||||
# tests/benchmarks/json_view/README.md).
|
||||
|
||||
on:
|
||||
pull_request:
|
||||
types: [labeled]
|
||||
workflow_dispatch:
|
||||
inputs:
|
||||
runner:
|
||||
description: "Runner image"
|
||||
type: choice
|
||||
options:
|
||||
- ubuntu-24.04
|
||||
- ubuntu-24.04-arm
|
||||
default: ubuntu-24.04
|
||||
compiler:
|
||||
description: "Compiler"
|
||||
type: choice
|
||||
options:
|
||||
- g++
|
||||
- clang++
|
||||
default: g++
|
||||
native:
|
||||
description: "Compile for the runner's CPU (-march=native)"
|
||||
type: boolean
|
||||
default: false
|
||||
rounds:
|
||||
description: "Rounds of bench_view"
|
||||
type: number
|
||||
default: 30
|
||||
|
||||
permissions:
|
||||
contents: read
|
||||
|
||||
concurrency:
|
||||
# (the label is part of the group: adding an unrelated label must not cancel a running benchmark)
|
||||
group: json-view-benchmarks-${{ github.workflow }}-${{ github.ref }}-${{ github.event.label.name }}
|
||||
cancel-in-progress: true
|
||||
|
||||
jobs:
|
||||
compare:
|
||||
if: github.event_name == 'workflow_dispatch' || github.event.label.name == 'benchmark'
|
||||
strategy:
|
||||
matrix:
|
||||
runner: ${{ fromJSON(github.event_name == 'workflow_dispatch' && format('["{0}"]', inputs.runner) || '["ubuntu-24.04", "ubuntu-24.04-arm"]') }}
|
||||
runs-on: ${{ matrix.runner }}
|
||||
timeout-minutes: 60
|
||||
steps:
|
||||
- name: Harden Runner
|
||||
uses: step-security/harden-runner@ccd8616d44fd3846e67624a50d5aad6d37bf2d25 # v2.22.1
|
||||
with:
|
||||
egress-policy: audit
|
||||
|
||||
- uses: actions/checkout@3d3c42e5aac5ba805825da76410c181273ba90b1 # v7.0.1
|
||||
with:
|
||||
persist-credentials: false
|
||||
|
||||
- name: Download test data
|
||||
run: |
|
||||
cmake -S . -B build -DJSON_BuildTests=On
|
||||
cmake --build build --target download_test_data
|
||||
|
||||
- name: Run the comparison
|
||||
env:
|
||||
CXX: ${{ inputs.compiler || 'g++' }}
|
||||
CC: ${{ inputs.compiler == 'clang++' && 'clang' || 'gcc' }}
|
||||
ROUNDS: ${{ inputs.rounds || 30 }}
|
||||
NATIVE: ${{ inputs.native && '--native' || '' }}
|
||||
run: python3 tests/benchmarks/json_view/compare.py --data build/test_files --download --rounds "$ROUNDS" $NATIVE
|
||||
|
||||
- name: Summary
|
||||
run: cat tests/benchmarks/json_view/results/*.md >> "$GITHUB_STEP_SUMMARY"
|
||||
|
||||
- uses: actions/upload-artifact@cf430e030ddbb5b0abf93d22962f4752f3646cd9 # v7.0.2
|
||||
with:
|
||||
name: json_view-benchmarks-${{ matrix.runner }}-${{ inputs.compiler || 'g++' }}
|
||||
path: tests/benchmarks/json_view/results/
|
||||
@@ -80,6 +80,6 @@ jobs:
|
||||
|
||||
# Upload the results to GitHub's code scanning dashboard.
|
||||
- name: "Upload to code-scanning"
|
||||
uses: github/codeql-action/upload-sarif@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
|
||||
uses: github/codeql-action/upload-sarif@6f2ac81f5cd81fe351a197ba0b00d91d03cd2aee # v4.39.0
|
||||
with:
|
||||
sarif_file: results.sarif
|
||||
@@ -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.
|
||||
@@ -65,7 +65,7 @@ jobs:
|
||||
|
||||
# Upload SARIF file generated in previous step
|
||||
- name: Upload SARIF file
|
||||
uses: github/codeql-action/upload-sarif@24c54180a607b1449ed407dd24f251e4e9147c8d # v4.38.3
|
||||
uses: github/codeql-action/upload-sarif@6f2ac81f5cd81fe351a197ba0b00d91d03cd2aee # v4.39.0
|
||||
with:
|
||||
sarif_file: semgrep.sarif
|
||||
if: always()
|
||||
@@ -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
|
||||
|
||||
@@ -3,7 +3,6 @@
|
||||
*.gcno
|
||||
*.gcda
|
||||
.DS_Store
|
||||
__pycache__/
|
||||
|
||||
/.idea
|
||||
/cmake-build-*
|
||||
@@ -45,10 +44,6 @@ venv
|
||||
|
||||
nlohmann_json.spdx
|
||||
|
||||
# api_checker: ephemeral, location/doc-status-sensitive working file (not the committed
|
||||
# release-tracking artifact -- see tools/api_checker/api_surface.json for that)
|
||||
/tools/api_checker/api_snapshot.json
|
||||
|
||||
# Bazel-related
|
||||
MODULE.bazel.lock
|
||||
|
||||
|
||||
@@ -37,6 +37,7 @@ cc_library(
|
||||
"include/nlohmann/detail/input/parser.hpp",
|
||||
"include/nlohmann/detail/input/position_t.hpp",
|
||||
"include/nlohmann/detail/input/pow5_table.hpp",
|
||||
"include/nlohmann/detail/input/simd_scan.hpp",
|
||||
"include/nlohmann/detail/input/string_scan.hpp",
|
||||
"include/nlohmann/detail/iterators/internal_iterator.hpp",
|
||||
"include/nlohmann/detail/iterators/iter_impl.hpp",
|
||||
|
||||
@@ -6,6 +6,7 @@ This file describes the source for supporting files; that is, files that are not
|
||||
- [GitHub](#github)
|
||||
- [REUSE](#reuse)
|
||||
- [Package Managers](#package-managers)
|
||||
- [Debugging](#debugging)
|
||||
|
||||
## Continuous Integration
|
||||
|
||||
@@ -289,3 +290,29 @@ The module definition for [Bazel](https://bazel.build)'s [Bzlmod](https://bazel.
|
||||
Further documentation:
|
||||
|
||||
- [Bazel modules](https://bazel.build/external/module)
|
||||
|
||||
## Debugging
|
||||
|
||||
### `nlohmann_json.natvis`
|
||||
|
||||
The [Natvis](https://learn.microsoft.com/en-us/visualstudio/debugger/create-custom-views-of-native-objects) file that
|
||||
gives `json` values a friendly view in the Visual Studio debugger. The file is generated by
|
||||
`tools/generate_natvis/generate_natvis.py` from the template `tools/generate_natvis/nlohmann_json.natvis.j2` and the ABI
|
||||
tags and version in `include/nlohmann/detail/abi_macros.hpp`; change the script or the template rather than editing
|
||||
the file by hand. The file can be updated by calling
|
||||
|
||||
```shell
|
||||
make natvis
|
||||
```
|
||||
|
||||
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,_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.
|
||||
|
||||
Further documentation:
|
||||
|
||||
- [Create custom views of C++ objects in the debugger using the Natvis framework](https://learn.microsoft.com/en-us/visualstudio/debugger/create-custom-views-of-native-objects)
|
||||
@@ -46,7 +46,7 @@ all:
|
||||
@echo "clean - remove built files"
|
||||
@echo "(fuzzers) - see tests/fuzzing.md, or run 'make -C tests fuzzers' to build the AFL fuzzers"
|
||||
@echo "macro_builder_check - check that macro_scope.hpp matches tools/macro_builder's output"
|
||||
@echo "natvis - regenerate nlohmann_json.natvis from the current ABI tags and version"
|
||||
@echo "natvis - regenerate nlohmann_json.natvis from the current ABI tags and version (pass generator options via NATVIS_ARGS, see tools/generate_natvis/README.md)"
|
||||
@echo "pretty - beautify code with Artistic Style"
|
||||
@echo "pvs_studio - run the PVS-Studio static analyzer and open the report"
|
||||
@echo "release - create the release files (include.zip, json.tar.xz, single headers, signatures, hashes)"
|
||||
@@ -120,13 +120,15 @@ $(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,_vns --output my.natvis"
|
||||
NATVIS_ARGS=
|
||||
|
||||
# regenerate nlohmann_json.natvis from the ABI tags and version in include/nlohmann/detail/abi_macros.hpp
|
||||
# (the dependencies are installed into a virtual environment first)
|
||||
natvis:
|
||||
@test -d $(NATVIS_VENV) || python3 -mvenv $(NATVIS_VENV)
|
||||
@$(NATVIS_VENV)/bin/python3 -c 'import jinja2' 2>/dev/null || $(NATVIS_VENV)/bin/pip3 install --quiet -r tools/generate_natvis/requirements.txt
|
||||
$(NATVIS_VENV)/bin/python3 tools/generate_natvis/generate_natvis.py .
|
||||
$(NATVIS_VENV)/bin/python3 tools/generate_natvis/generate_natvis.py $(NATVIS_ARGS) .
|
||||
|
||||
# regenerate the two tools/macro_builder blocks of $(MACRO_SCOPE_HPP) (see its README.md) and diff against the
|
||||
# checked-in header; phony, because it never writes $(MACRO_SCOPE_HPP) itself
|
||||
|
||||
@@ -105,7 +105,7 @@ Thanks everyone!
|
||||
|
||||
:books: If you want to **learn more** about how to use the library, check out the rest of the [**README**](#examples), have a look at [**code examples**](https://github.com/nlohmann/json/tree/develop/docs/mkdocs/docs/examples), or browse through the [**help pages**](https://json.nlohmann.me).
|
||||
|
||||
:construction: If you want to understand the **API** better, check out the [**API Reference**](https://json.nlohmann.me/api/basic_json/) or have a look at the [quick reference](#quick-reference) below. The public API surface is derived mechanically and checked for documentation coverage by the tooling in [`tools/api_checker/`](tools/api_checker/), whose [POLICY.md](tools/api_checker/POLICY.md) defines what counts as public API and what stability is guaranteed.
|
||||
:construction: If you want to understand the **API** better, check out the [**API Reference**](https://json.nlohmann.me/api/basic_json/) or have a look at the [quick reference](#quick-reference) below.
|
||||
|
||||
:bug: If you found a **bug**, please check the [**FAQ**](https://json.nlohmann.me/home/faq/) if it is a known issue or the result of a design decision. Please also have a look at the [**issue list**](https://github.com/nlohmann/json/issues) before you [**create a new issue**](https://github.com/nlohmann/json/issues/new/choose). Please provide as much information as possible to help us understand and reproduce your issue.
|
||||
|
||||
|
||||
@@ -485,10 +485,8 @@ basic_json(basic_json&& other) noexcept;
|
||||
1. Since version 1.0.0.
|
||||
2. Since version 1.0.0.
|
||||
3. Since version 2.1.0.
|
||||
4. Since version 3.2.0. Also initializes the position reported by
|
||||
[`start_pos()`](start_pos.md)/[`end_pos()`](end_pos.md) from `val` when
|
||||
[`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) is enabled, since version 3.12.0. Explicit
|
||||
for different string types if `JSON_USE_IMPLICIT_CONVERSIONS` is `0` since version 3.13.0.
|
||||
4. Since version 3.2.0. Explicit for different string types if `JSON_USE_IMPLICIT_CONVERSIONS` is `0` since
|
||||
version 3.13.0.
|
||||
5. 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
|
||||
|
||||
@@ -1,38 +0,0 @@
|
||||
# <small>nlohmann::basic_json::</small>bjdata_version_t
|
||||
|
||||
```cpp
|
||||
enum class bjdata_version_t
|
||||
{
|
||||
draft2,
|
||||
draft3,
|
||||
};
|
||||
```
|
||||
|
||||
This enumeration is used in the [`to_bjdata`](to_bjdata.md) function to choose which draft version of
|
||||
the BJData specification to encode ND-array extensions for:
|
||||
|
||||
draft2
|
||||
: encode using the BJData Draft 2 ND-array format
|
||||
|
||||
draft3
|
||||
: encode using the BJData Draft 3 ND-array format
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how `bjdata_version_t` selects the BJData draft used by `to_bjdata`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/bjdata_version_t.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/bjdata_version_t.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.12.0.
|
||||
@@ -1,32 +0,0 @@
|
||||
# <small>nlohmann::basic_json::</small>initializer_list_t
|
||||
|
||||
```cpp
|
||||
using initializer_list_t = std::initializer_list<detail::json_ref<basic_json>>;
|
||||
```
|
||||
|
||||
The type used for the initializer-list [constructor](basic_json.md) (overload 5) and for functions
|
||||
such as [`operator=`](operator=.md) that accept a braced-init-list of JSON values. Each element wraps a
|
||||
`basic_json` value or something convertible to one, deferring the decision of whether the list should be
|
||||
parsed as a JSON array or a JSON object to the constructor itself.
|
||||
|
||||
See the [constructor](basic_json.md) documentation for how `initializer_list_t` values are interpreted.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how an `initializer_list_t` is used to construct a JSON value.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/initializer_list_t.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/initializer_list_t.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Since version 1.0.0.
|
||||
@@ -1,31 +0,0 @@
|
||||
# <small>nlohmann::basic_json::</small>json_sax_t
|
||||
|
||||
```cpp
|
||||
using json_sax_t = json_sax<basic_json>;
|
||||
```
|
||||
|
||||
The [`json_sax`](../json_sax/index.md) interface bound to this `basic_json` specialization, i.e. with
|
||||
`BasicJsonType` fixed to `basic_json`. Used as the SAX interface type by [`sax_parse`](sax_parse.md) and
|
||||
other SAX-based parsing functions.
|
||||
|
||||
See [`nlohmann::json_sax`](../json_sax/index.md) for more information.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows the type `json_sax_t`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/json_sax_t.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/json_sax_t.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.2.0.
|
||||
@@ -38,7 +38,7 @@ Strong guarantee: `source` and `target` are never modified.
|
||||
|
||||
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, or adding one to the patch): logarithmic for [`json`](../json.md), and linear for
|
||||
[`ordered_json`](../ordered_json.md) (see [`ordered_map` complexity](../ordered_map/index.md#complexity)). 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).
|
||||
|
||||
## Notes
|
||||
|
||||
@@ -51,5 +51,3 @@ Linear.
|
||||
## Version history
|
||||
|
||||
- Added in version 1.0.0.
|
||||
- The `noexcept` specification was extended to also depend on
|
||||
[`json_base_class_t`](json_base_class_t.md)'s move-assignment in version 3.11.3.
|
||||
@@ -92,8 +92,3 @@ Linear in the size of the JSON value.
|
||||
- Since version 1.0.0.
|
||||
- Macros `JSON_EXPLICIT`/[`JSON_USE_IMPLICIT_CONVERSIONS`](../macros/json_use_implicit_conversions.md) added
|
||||
in version 3.9.0.
|
||||
- The exclusion of `std::any` from this conversion became conditional on
|
||||
[`JSON_HAS_STATIC_RTTI`](../macros/json_has_static_rtti.md) in version 3.11.3.
|
||||
- `std::optional<T>` excluded from this conversion in version 3.13.0; use
|
||||
[`get<std::optional<T>>()`](get.md)/[`get_to()`](get_to.md) instead (see
|
||||
[Converting values](../../features/conversions.md)).
|
||||
@@ -1,32 +0,0 @@
|
||||
# <small>nlohmann::byte_container_with_subtype::</small>container_type
|
||||
|
||||
```cpp
|
||||
using container_type = BinaryType;
|
||||
```
|
||||
|
||||
The type of the underlying binary container, forwarded from the `BinaryType` template parameter that
|
||||
`byte_container_with_subtype` is instantiated with. `byte_container_with_subtype` publicly inherits from
|
||||
`container_type`.
|
||||
|
||||
See [`basic_json::binary_t`](../basic_json/binary_t.md) for the type typically used to instantiate
|
||||
`BinaryType`.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows the type `container_type`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/byte_container_with_subtype__container_type.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/byte_container_with_subtype__container_type.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Since version 3.8.0.
|
||||
@@ -1,28 +0,0 @@
|
||||
# <small>nlohmann::byte_container_with_subtype::</small>subtype_type
|
||||
|
||||
```cpp
|
||||
using subtype_type = std::uint64_t;
|
||||
```
|
||||
|
||||
The type used to store the optional binary subtype tag. See [`subtype`](subtype.md) and
|
||||
[`set_subtype`](set_subtype.md).
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows the type `subtype_type`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/byte_container_with_subtype__subtype_type.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/byte_container_with_subtype__subtype_type.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Since version 3.8.0.
|
||||
@@ -1,30 +0,0 @@
|
||||
# <small>nlohmann::json_sax::</small>binary_t
|
||||
|
||||
```cpp
|
||||
using binary_t = typename BasicJsonType::binary_t;
|
||||
```
|
||||
|
||||
The type used by the [`binary`](binary.md) callback for JSON binary values, forwarded from the
|
||||
`BasicJsonType` template parameter.
|
||||
|
||||
See [`basic_json::binary_t`](../basic_json/binary_t.md) for more information.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows the type `binary_t` and its relation to `basic_json::binary_t`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/json_sax__binary_t.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/json_sax__binary_t.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.8.0.
|
||||
@@ -1,33 +0,0 @@
|
||||
# <small>nlohmann::json_sax::</small>json_sax
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
json_sax() = default;
|
||||
|
||||
// (2)
|
||||
json_sax(const json_sax&) = default;
|
||||
|
||||
// (3)
|
||||
json_sax(json_sax&&) noexcept = default;
|
||||
```
|
||||
|
||||
1. Default constructor.
|
||||
2. Copy constructor.
|
||||
3. Move constructor.
|
||||
|
||||
`json_sax` is a pure abstract base class with no data members of its own, so all three constructors are
|
||||
defaulted and only exist to make derived SAX consumers explicitly copyable/movable.
|
||||
|
||||
## Exception safety
|
||||
|
||||
No-throw guarantee: none of these constructors throw exceptions.
|
||||
|
||||
## Complexity
|
||||
|
||||
Constant.
|
||||
|
||||
<!-- NOLINT Examples -->
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.2.0.
|
||||
@@ -1,30 +0,0 @@
|
||||
# <small>nlohmann::json_sax::</small>number_float_t
|
||||
|
||||
```cpp
|
||||
using number_float_t = typename BasicJsonType::number_float_t;
|
||||
```
|
||||
|
||||
The type used by the [`number_float`](number_float.md) callback for JSON floating-point numbers,
|
||||
forwarded from the `BasicJsonType` template parameter.
|
||||
|
||||
See [`basic_json::number_float_t`](../basic_json/number_float_t.md) for more information.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows the type `number_float_t` and its relation to `basic_json::number_float_t`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/json_sax__number_float_t.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/json_sax__number_float_t.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.2.0.
|
||||
@@ -1,30 +0,0 @@
|
||||
# <small>nlohmann::json_sax::</small>number_integer_t
|
||||
|
||||
```cpp
|
||||
using number_integer_t = typename BasicJsonType::number_integer_t;
|
||||
```
|
||||
|
||||
The type used by the [`number_integer`](number_integer.md) callback for JSON integer numbers, forwarded
|
||||
from the `BasicJsonType` template parameter.
|
||||
|
||||
See [`basic_json::number_integer_t`](../basic_json/number_integer_t.md) for more information.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows the type `number_integer_t` and its relation to `basic_json::number_integer_t`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/json_sax__number_integer_t.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/json_sax__number_integer_t.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.2.0.
|
||||
@@ -1,30 +0,0 @@
|
||||
# <small>nlohmann::json_sax::</small>number_unsigned_t
|
||||
|
||||
```cpp
|
||||
using number_unsigned_t = typename BasicJsonType::number_unsigned_t;
|
||||
```
|
||||
|
||||
The type used by the [`number_unsigned`](number_unsigned.md) callback for JSON unsigned integer numbers,
|
||||
forwarded from the `BasicJsonType` template parameter.
|
||||
|
||||
See [`basic_json::number_unsigned_t`](../basic_json/number_unsigned_t.md) for more information.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows the type `number_unsigned_t` and its relation to `basic_json::number_unsigned_t`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/json_sax__number_unsigned_t.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/json_sax__number_unsigned_t.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.2.0.
|
||||
@@ -1,29 +0,0 @@
|
||||
# <small>nlohmann::json_sax::</small>operator=
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
json_sax& operator=(const json_sax&) = default;
|
||||
|
||||
// (2)
|
||||
json_sax& operator=(json_sax&&) noexcept = default;
|
||||
```
|
||||
|
||||
1. Copy assignment operator.
|
||||
2. Move assignment operator.
|
||||
|
||||
`json_sax` is a pure abstract base class with no data members of its own, so both assignment operators
|
||||
are defaulted and only exist to make derived SAX consumers explicitly copy-/move-assignable.
|
||||
|
||||
## Exception safety
|
||||
|
||||
No-throw guarantee: neither operator throws exceptions.
|
||||
|
||||
## Complexity
|
||||
|
||||
Constant.
|
||||
|
||||
<!-- NOLINT Examples -->
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.2.0.
|
||||
@@ -1,30 +0,0 @@
|
||||
# <small>nlohmann::json_sax::</small>string_t
|
||||
|
||||
```cpp
|
||||
using string_t = typename BasicJsonType::string_t;
|
||||
```
|
||||
|
||||
The type used by the [`string`](string.md) and [`key`](key.md) callbacks for JSON strings and object
|
||||
keys, forwarded from the `BasicJsonType` template parameter.
|
||||
|
||||
See [`basic_json::string_t`](../basic_json/string_t.md) for more information.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows the type `string_t` and its relation to `basic_json::string_t`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/json_sax__string_t.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/json_sax__string_t.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.2.0.
|
||||
@@ -1,22 +0,0 @@
|
||||
# <small>nlohmann::json_sax::</small>~json_sax
|
||||
|
||||
```cpp
|
||||
virtual ~json_sax() = default;
|
||||
```
|
||||
|
||||
Destructor. Virtual to allow proper destruction of derived SAX consumer classes through a
|
||||
pointer/reference to `json_sax`.
|
||||
|
||||
## Exception safety
|
||||
|
||||
No-throw guarantee: this destructor never throws exceptions.
|
||||
|
||||
## Complexity
|
||||
|
||||
Constant.
|
||||
|
||||
<!-- NOLINT Examples -->
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.2.0.
|
||||
@@ -38,6 +38,7 @@ header. See also the [macro overview page](../../features/macros.md).
|
||||
- [**JSON_HAS_THREE_WAY_COMPARISON**](json_has_three_way_comparison.md) - control 3-way comparison support
|
||||
- [**JSON_NO_AUTOMATIC_UDLS**](json_no_automatic_udls.md) - do not include the user-defined string literals (UDLs) automatically
|
||||
- [**JSON_NO_IO**](json_no_io.md) - switch off functions relying on certain C++ I/O headers
|
||||
- [**JSON_NO_SIMD**](json_no_simd.md) - use only portable code instead of vector instructions (SSE2, SSSE3, NEON)
|
||||
- [**JSON_NO_THREAD_LOCAL**](json_no_thread_local.md) - switch off the use of `thread_local` storage
|
||||
- [**JSON_SKIP_UNSUPPORTED_COMPILER_CHECK**](json_skip_unsupported_compiler_check.md) - do not warn about unsupported compilers
|
||||
- [**JSON_USE_GLOBAL_UDLS**](json_use_global_udls.md) - place user-defined string literals (UDLs) into the global namespace
|
||||
|
||||
@@ -0,0 +1,83 @@
|
||||
# JSON_NO_SIMD
|
||||
|
||||
```cpp
|
||||
#define JSON_NO_SIMD
|
||||
```
|
||||
|
||||
When defined, the library uses only portable C++ code where it would otherwise use vector instructions: when scanning
|
||||
strings during parsing, and when writing floating-point numbers during serialization.
|
||||
|
||||
The macro is an escape hatch, for example for toolchains that cannot compile the vector code, for sanitizers or
|
||||
analyzers that do not understand it, or to compare the speed of both variants. It does not change any result: values,
|
||||
exceptions, and error positions are the same either way. Only the speed differs.
|
||||
|
||||
## Default definition
|
||||
|
||||
By default, `#!cpp JSON_NO_SIMD` is not defined, and vector instructions are used where the target has them.
|
||||
|
||||
```cpp
|
||||
#undef JSON_NO_SIMD
|
||||
```
|
||||
|
||||
## Notes
|
||||
|
||||
!!! note "Which instructions are used"
|
||||
|
||||
- **x86-64:** SSE2, which every x86-64 CPU has, finds the end of runs of plain string characters 16 bytes at a time
|
||||
and writes the digits of floating-point numbers. The UTF-8 check of non-ASCII text needs SSSE3, which is not part
|
||||
of x86-64: it is compiled for SSSE3 with a function attribute and used when the CPU has SSSE3 (every x86-64 CPU
|
||||
since about 2011), else the portable check. Code compiled for SSSE3 anyway (e.g., with `-mssse3` or `-march=native`)
|
||||
skips this check of the CPU. 32-bit x86 uses SSE2 for strings when the compiler targets it.
|
||||
- **AArch64:** NEON, which every 64-bit Arm CPU has, checks UTF-8 text and long runs of plain string characters 16
|
||||
bytes at a time, and writes the digits of floating-point numbers. With MSVC, only the floating-point digits use
|
||||
NEON.
|
||||
- **Other targets:** portable code only.
|
||||
|
||||
Strings are only scanned this way for contiguous input and for the characters a `#!cpp std::istream` holds in its
|
||||
stream buffer (see [`JSON_DISABLE_STREAM_BULK_SCAN`](json_disable_stream_bulk_scan.md)); other inputs are read one
|
||||
character at a time.
|
||||
|
||||
!!! note "Interaction with `JSON_USE_SIMDUTF`"
|
||||
|
||||
With [`JSON_USE_SIMDUTF`](json_use_simdutf.md), runs of string characters are first validated by simdutf; the code
|
||||
described here is used for what simdutf does not accept, so that errors are reported at the same position.
|
||||
`JSON_NO_SIMD` does not affect simdutf.
|
||||
|
||||
!!! note "ABI compatibility"
|
||||
|
||||
The macro selects between two definitions of the library's internal scanning and formatting functions. Whether it
|
||||
is defined is encoded in the [namespace](../../features/namespace.md) (tag `_ns`), 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.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example "Example: switching off vector instructions"
|
||||
|
||||
The program parses and serializes the same values with and without the macro:
|
||||
|
||||
```cpp
|
||||
#define JSON_NO_SIMD
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
int main()
|
||||
{
|
||||
const json j = json::parse(R"({"name": "日本語 text", "pi": 3.141592653589793})");
|
||||
std::cout << j.dump() << '\n'; // {"name":"日本語 text","pi":3.141592653589793}
|
||||
}
|
||||
```
|
||||
|
||||
## See also
|
||||
|
||||
- [**parse**](../basic_json/parse.md) - deserialize from a compatible input
|
||||
- [**dump**](../basic_json/dump.md) - serialization
|
||||
- [**JSON_USE_SIMDUTF**](json_use_simdutf.md) - use the simdutf library to accelerate UTF-8 validation
|
||||
- [**JSON_DISABLE_STREAM_BULK_SCAN**](json_disable_stream_bulk_scan.md) - read a `std::istream` one character at a time
|
||||
- [Parsing: input sources and performance](../../features/parsing/index.md#input-sources-and-performance)
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.13.0.
|
||||
@@ -6,8 +6,9 @@
|
||||
|
||||
When defined, the parser validates the UTF-8 content of JSON strings that come from a **contiguous byte input**
|
||||
(`std::string`, `std::vector<char>`/`<std::uint8_t>`, string literals, `const char*` ranges, …) using the
|
||||
[simdutf](https://github.com/simdutf/simdutf) library instead of the built-in scalar validator. On text with many
|
||||
non-ASCII characters (e.g. CJK or emoji) this can validate several times faster.
|
||||
[simdutf](https://github.com/simdutf/simdutf) library instead of the built-in validator (which uses SSSE3 or NEON where
|
||||
available, see [`JSON_NO_SIMD`](json_no_simd.md)). On text with many non-ASCII characters (e.g. CJK or emoji) this can
|
||||
validate faster, depending on the CPU.
|
||||
|
||||
This is an **opt-in external dependency**. The library itself remains header-only and its behavior is unchanged: the
|
||||
same input is accepted or rejected either way, and every parse error is reported at the same position with the same
|
||||
|
||||
@@ -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`, `_vns`, and
|
||||
`_vssse3` 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).
|
||||
@@ -8,16 +8,16 @@ This type preserves the insertion order of object keys.
|
||||
|
||||
## Iterator invalidation
|
||||
|
||||
The type is based on [`ordered_map`](ordered_map/index.md) which in turn uses a `std::vector` to store object elements.
|
||||
The type is based on [`ordered_map`](ordered_map.md) which in turn uses a `std::vector` to store object elements.
|
||||
Therefore, adding object elements can yield a reallocation in which case all iterators (including the
|
||||
[`end()`](basic_json/end.md) iterator) and all references to the elements are invalidated. Also, any iterator or
|
||||
reference after the insertion point will point to the same index, which is now a different value.
|
||||
|
||||
## Complexity
|
||||
|
||||
[`ordered_map`](ordered_map/index.md) has no lookup index: every key-based object operation is a linear scan, so building or
|
||||
[`ordered_map`](ordered_map.md) has no lookup index: every key-based object operation is a linear scan, so building or
|
||||
parsing an object of `n` keys costs O(n²) rather than O(n log n). See
|
||||
[`ordered_map` complexity](ordered_map/index.md#complexity) for the per-operation table and for measured numbers.
|
||||
[`ordered_map` complexity](ordered_map.md#complexity) for the per-operation table and for measured numbers.
|
||||
|
||||
## Examples
|
||||
|
||||
@@ -37,7 +37,7 @@ parsing an object of `n` keys costs O(n²) rather than O(n log n). See
|
||||
|
||||
## See also
|
||||
|
||||
- [ordered_map](ordered_map/index.md)
|
||||
- [ordered_map](ordered_map.md)
|
||||
- [Object Order](../features/object_order.md)
|
||||
|
||||
## Version history
|
||||
|
||||
@@ -6,7 +6,7 @@ template<class Key, class T, class IgnoredLess = std::less<Key>,
|
||||
struct ordered_map : std::vector<std::pair<const Key, T>, Allocator>;
|
||||
```
|
||||
|
||||
A minimal map-like container that preserves insertion order for use within [`nlohmann::ordered_json`](../ordered_json.md)
|
||||
A minimal map-like container that preserves insertion order for use within [`nlohmann::ordered_json`](ordered_json.md)
|
||||
(`nlohmann::basic_json<ordered_map>`).
|
||||
|
||||
## Template parameters
|
||||
@@ -30,19 +30,19 @@ case all iterators (including the `end()` iterator) and all references to the el
|
||||
|
||||
When the storage grows, the keys are copied and the mapped values are moved to the new storage. A plain `std::vector`
|
||||
would copy the whole elements instead, because their `#!cpp const` keys make them not nothrow move constructible; for
|
||||
[`ordered_json`](../ordered_json.md), this would be a deep copy of every nested value. The values are only copied if
|
||||
[`ordered_json`](ordered_json.md), this would be a deep copy of every nested value. The values are only copied if
|
||||
`T` is not default constructible or not nothrow move assignable.
|
||||
|
||||
## Member types
|
||||
|
||||
- **key_type** - key type (`Key`)
|
||||
- **mapped_type** - mapped type (`T`)
|
||||
- [**Container**](Container.md) - base container type (`#!cpp std::vector<std::pair<const Key, T>, Allocator>`)
|
||||
- **Container** - base container type (`#!cpp std::vector<std::pair<const Key, T>, Allocator>`)
|
||||
- **iterator**
|
||||
- **const_iterator**
|
||||
- **size_type**
|
||||
- **value_type**
|
||||
- [**key_compare**](key_compare.md) - key comparison function
|
||||
- **key_compare** - key comparison function
|
||||
```cpp
|
||||
std::equal_to<Key> // until C++14
|
||||
|
||||
@@ -51,16 +51,15 @@ std::equal_to<> // since C++14
|
||||
|
||||
## Member functions
|
||||
|
||||
- [(constructor)](ordered_map.md)
|
||||
- [(destructor)](~ordered_map.md)
|
||||
- [**operator=**](operator=.md)
|
||||
- [**emplace**](emplace.md)
|
||||
- [**operator\[\]**](operator[].md)
|
||||
- [**at**](at.md)
|
||||
- [**erase**](erase.md)
|
||||
- [**count**](count.md)
|
||||
- [**find**](find.md)
|
||||
- [**insert**](insert.md)
|
||||
- (constructor)
|
||||
- (destructor)
|
||||
- **emplace**
|
||||
- **operator\[\]**
|
||||
- **at**
|
||||
- **erase**
|
||||
- **count**
|
||||
- **find**
|
||||
- **insert**
|
||||
|
||||
## Exception safety
|
||||
|
||||
@@ -90,7 +89,7 @@ This differs from `#!cpp std::map`, where the same operations are O(log n).
|
||||
!!! warning "Quadratic cost of building large objects"
|
||||
|
||||
Because every insertion scans all elements inserted so far, building an object of `n` distinct keys costs
|
||||
**O(n²)** in total. This applies to filling an [`ordered_json`](../ordered_json.md) object key by key as well as to
|
||||
**O(n²)** in total. This applies to filling an [`ordered_json`](ordered_json.md) object key by key as well as to
|
||||
parsing one, since the parser inserts each key as it is read.
|
||||
|
||||
The cost is negligible for the object sizes typically found in configuration files or API payloads, but it grows
|
||||
@@ -107,7 +106,7 @@ This differs from `#!cpp std::map`, where the same operations are O(log n).
|
||||
If key order matters for objects of that size, consider a container with a lookup index, such as
|
||||
[`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map)
|
||||
([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)), as the object type -- see
|
||||
[object order](../../features/object_order.md).
|
||||
[object order](../features/object_order.md).
|
||||
|
||||
## Examples
|
||||
|
||||
@@ -127,10 +126,10 @@ This differs from `#!cpp std::map`, where the same operations are O(log n).
|
||||
|
||||
## See also
|
||||
|
||||
- [ordered_json](../ordered_json.md)
|
||||
- [ordered_json](ordered_json.md)
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](ordered_json.md).
|
||||
- Added **key_compare** member in version 3.11.0.
|
||||
- Changed in version 3.13.0: growing the storage moves the mapped values instead of copying them.
|
||||
@@ -1,28 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>Container
|
||||
|
||||
```cpp
|
||||
using Container = std::vector<std::pair<const Key, T>, Allocator>;
|
||||
```
|
||||
|
||||
The base container type that `ordered_map` publicly inherits from. Elements are stored in insertion
|
||||
order as `#!cpp std::pair<const Key, T>` entries in a `std::vector`.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows the type `Container`.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/ordered_map__Container.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/ordered_map__Container.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
@@ -1,61 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>at
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
T& at(const key_type& key);
|
||||
const T& at(const key_type& key) const;
|
||||
|
||||
// (2)
|
||||
template<class KeyType>
|
||||
T& at(KeyType&& key);
|
||||
template<class KeyType>
|
||||
const T& at(KeyType&& key) const;
|
||||
```
|
||||
|
||||
1. Returns a reference to the value mapped to `key`.
|
||||
2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
(heterogeneous lookup, e.g. looking up by a `#!cpp const char*` without constructing a temporary
|
||||
`key_type`). Only participates in overload resolution if `KeyType` is usable as a key type.
|
||||
|
||||
## Template parameters
|
||||
|
||||
`KeyType`
|
||||
: a type comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
|
||||
## Parameters
|
||||
|
||||
`key` (in)
|
||||
: key of the element to find
|
||||
|
||||
## Return value
|
||||
|
||||
reference to the mapped value of the element with key equal to `key`
|
||||
|
||||
## Exceptions
|
||||
|
||||
Throws `std::out_of_range` if no element with key `key` exists.
|
||||
|
||||
## Complexity
|
||||
|
||||
Linear in the number of elements.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how `at` is used.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/ordered_map__at.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/ordered_map__at.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.1 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
- Overload (2) added in version 3.11.0.
|
||||
@@ -1,53 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>count
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
size_type count(const key_type& key) const;
|
||||
|
||||
// (2)
|
||||
template<class KeyType>
|
||||
size_type count(KeyType&& key) const;
|
||||
```
|
||||
|
||||
1. Returns the number of elements with key equal to `key` (0 or 1, since keys are unique).
|
||||
2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
(heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
|
||||
|
||||
## Template parameters
|
||||
|
||||
`KeyType`
|
||||
: a type comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
|
||||
## Parameters
|
||||
|
||||
`key` (in)
|
||||
: key of the elements to count
|
||||
|
||||
## Return value
|
||||
|
||||
number of elements with key equal to `key` (0 or 1)
|
||||
|
||||
## Complexity
|
||||
|
||||
Linear in the number of elements.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how `count` is used.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/ordered_map__count.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/ordered_map__count.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.1 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
- Overload (2) added in version 3.11.0.
|
||||
@@ -1,58 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>emplace
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
std::pair<iterator, bool> emplace(const key_type& key, T&& t);
|
||||
|
||||
// (2)
|
||||
template<class KeyType>
|
||||
std::pair<iterator, bool> emplace(KeyType&& key, T&& t);
|
||||
```
|
||||
|
||||
1. Inserts `#!cpp {key, t}` if no element with an equal key already exists (per [`key_compare`](key_compare.md)),
|
||||
appending it at the end to preserve insertion order. If an equal key already exists, does nothing.
|
||||
2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
(heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
|
||||
|
||||
## Template parameters
|
||||
|
||||
`KeyType`
|
||||
: a type comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
|
||||
## Parameters
|
||||
|
||||
`key` (in)
|
||||
: key of the element to insert
|
||||
|
||||
`t` (in)
|
||||
: value of the element to insert
|
||||
|
||||
## Return value
|
||||
|
||||
pair of an iterator to the (possibly newly inserted) element, and a `bool` that is `true` if insertion
|
||||
took place and `false` if an element with an equal key already existed
|
||||
|
||||
## Complexity
|
||||
|
||||
Linear in the number of elements.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how `emplace` is used.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/ordered_map__emplace.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/ordered_map__emplace.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
- Overload (2) added in version 3.11.0.
|
||||
@@ -1,75 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>erase
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
size_type erase(const key_type& key);
|
||||
|
||||
// (2)
|
||||
template<class KeyType>
|
||||
size_type erase(KeyType&& key);
|
||||
|
||||
// (3)
|
||||
iterator erase(iterator pos);
|
||||
|
||||
// (4)
|
||||
iterator erase(iterator first, iterator last);
|
||||
```
|
||||
|
||||
1. Removes the element with key equal to `key`, if any, preserving the relative order of the remaining
|
||||
elements.
|
||||
2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
(heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
|
||||
3. Removes the element at `pos`.
|
||||
4. Removes the elements in range `[first, last)`.
|
||||
|
||||
## Template parameters
|
||||
|
||||
`KeyType`
|
||||
: a type comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
|
||||
## Parameters
|
||||
|
||||
`key` (in)
|
||||
: key of the element to remove
|
||||
|
||||
`pos` (in)
|
||||
: iterator to the element to remove
|
||||
|
||||
`first` (in)
|
||||
: iterator to the first element to remove
|
||||
|
||||
`last` (in)
|
||||
: iterator one past the last element to remove
|
||||
|
||||
## Return value
|
||||
|
||||
1. number of elements removed (0 or 1)
|
||||
2. number of elements removed (0 or 1)
|
||||
3. iterator following the removed element
|
||||
4. iterator following the last removed element
|
||||
|
||||
## Complexity
|
||||
|
||||
Linear in the number of elements (elements after the removed one(s) are shifted to keep storage
|
||||
contiguous).
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how `erase` is used.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/ordered_map__erase.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/ordered_map__erase.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
- Overload (2) added in version 3.11.0.
|
||||
@@ -1,56 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>find
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
iterator find(const key_type& key);
|
||||
const_iterator find(const key_type& key) const;
|
||||
|
||||
// (2)
|
||||
template<class KeyType>
|
||||
iterator find(KeyType&& key);
|
||||
template<class KeyType>
|
||||
const_iterator find(KeyType&& key) const;
|
||||
```
|
||||
|
||||
1. Returns an iterator to the element with key equal to `key`, or `end()` if no such element exists.
|
||||
2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
(heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
|
||||
|
||||
## Template parameters
|
||||
|
||||
`KeyType`
|
||||
: a type comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
|
||||
## Parameters
|
||||
|
||||
`key` (in)
|
||||
: key of the element to find
|
||||
|
||||
## Return value
|
||||
|
||||
iterator to the element with key equal to `key`, or `end()` if not found
|
||||
|
||||
## Complexity
|
||||
|
||||
Linear in the number of elements.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how `find` is used.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/ordered_map__find.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/ordered_map__find.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.1 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
- Overload (2) added in version 3.11.0.
|
||||
@@ -1,63 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>insert
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
std::pair<iterator, bool> insert(value_type&& value);
|
||||
std::pair<iterator, bool> insert(const value_type& value);
|
||||
|
||||
// (2)
|
||||
template<typename InputIt>
|
||||
void insert(InputIt first, InputIt last);
|
||||
```
|
||||
|
||||
1. Inserts `value` if no element with an equal key already exists (per [`key_compare`](key_compare.md)),
|
||||
appending it at the end to preserve insertion order. If an equal key already exists, does nothing.
|
||||
2. Inserts the elements from range `[first, last)`, in iteration order, applying the same equal-key rule
|
||||
as (1) to each element.
|
||||
|
||||
## Template parameters
|
||||
|
||||
`InputIt`
|
||||
: an input iterator type
|
||||
|
||||
## Parameters
|
||||
|
||||
`value` (in)
|
||||
: value to insert
|
||||
|
||||
`first` (in)
|
||||
: iterator to the first element to insert
|
||||
|
||||
`last` (in)
|
||||
: iterator one past the last element to insert
|
||||
|
||||
## Return value
|
||||
|
||||
1. pair of an iterator to the (possibly newly inserted) element, and a `bool` that is `true` if insertion
|
||||
took place and `false` if an element with an equal key already existed
|
||||
2. (none)
|
||||
|
||||
## Complexity
|
||||
|
||||
1. Linear in the number of elements.
|
||||
2. Linear in the distance between `first` and `last`, times linear in the number of elements.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how `insert` is used.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/ordered_map__insert.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/ordered_map__insert.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.1 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
@@ -1,34 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>key_compare
|
||||
|
||||
```cpp
|
||||
using key_compare = std::equal_to<Key>; // until C++14
|
||||
|
||||
using key_compare = std::equal_to<>; // since C++14
|
||||
```
|
||||
|
||||
The comparator used to determine key equality when looking up elements. Unlike `std::map`, `ordered_map`
|
||||
uses linear search with `key_compare` rather than an ordering relation, since element order reflects
|
||||
insertion order rather than key order.
|
||||
|
||||
Since C++14, the transparent `#!cpp std::equal_to<>` is used, which enables heterogeneous lookup (e.g.
|
||||
looking up by a `#!cpp const char*` key without constructing a temporary `Key`).
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how `key_compare` is used.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/ordered_map__key_compare.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/ordered_map__key_compare.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.11.0.
|
||||
@@ -1,32 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>operator=
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
ordered_map& operator=(const ordered_map& other);
|
||||
|
||||
// (2)
|
||||
ordered_map& operator=(ordered_map&& other) noexcept(std::is_nothrow_move_assignable<Container>::value);
|
||||
```
|
||||
|
||||
1. Copy assignment operator.
|
||||
2. Move assignment operator.
|
||||
|
||||
## Parameters
|
||||
|
||||
`other` (in)
|
||||
: value to assign from
|
||||
|
||||
## Return value
|
||||
|
||||
`*this`
|
||||
|
||||
## Complexity
|
||||
|
||||
1. Linear in the size of `other`.
|
||||
2. Constant.
|
||||
|
||||
<!-- NOLINT Examples -->
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
@@ -1,62 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>operator[]
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
T& operator[](const key_type& key);
|
||||
const T& operator[](const key_type& key) const;
|
||||
|
||||
// (2)
|
||||
template<class KeyType>
|
||||
T& operator[](KeyType&& key);
|
||||
template<class KeyType>
|
||||
const T& operator[](KeyType&& key) const;
|
||||
```
|
||||
|
||||
1. Returns a reference to the value mapped to `key`, inserting a default-constructed `T` (non-`const`
|
||||
overload only) if no such element exists yet.
|
||||
2. Same as (1), but for any `KeyType` comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
(heterogeneous lookup). Only participates in overload resolution if `KeyType` is usable as a key type.
|
||||
|
||||
## Template parameters
|
||||
|
||||
`KeyType`
|
||||
: a type comparable to `key_type` via [`key_compare`](key_compare.md)
|
||||
|
||||
## Parameters
|
||||
|
||||
`key` (in)
|
||||
: key of the element to find or insert
|
||||
|
||||
## Return value
|
||||
|
||||
reference to the mapped value of the element with key equal to `key`
|
||||
|
||||
## Exceptions
|
||||
|
||||
The `const` overloads throw `std::out_of_range` if no element with key `key` exists (they delegate to
|
||||
[`at`](at.md)).
|
||||
|
||||
## Complexity
|
||||
|
||||
Linear in the number of elements.
|
||||
|
||||
## Examples
|
||||
|
||||
??? example
|
||||
|
||||
The example shows how `operator[]` is used.
|
||||
|
||||
```cpp
|
||||
--8<-- "examples/ordered_map__operator_idx.cpp"
|
||||
```
|
||||
|
||||
Output:
|
||||
|
||||
```
|
||||
--8<-- "examples/ordered_map__operator_idx.output"
|
||||
```
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
- Overload (2) added in version 3.11.0.
|
||||
@@ -1,66 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>ordered_map
|
||||
|
||||
```cpp
|
||||
// (1)
|
||||
ordered_map() noexcept(noexcept(Container()));
|
||||
|
||||
// (2)
|
||||
explicit ordered_map(const Allocator& alloc) noexcept(noexcept(Container(alloc)));
|
||||
|
||||
// (3)
|
||||
template <class It>
|
||||
ordered_map(It first, It last, const Allocator& alloc = Allocator());
|
||||
|
||||
// (4)
|
||||
ordered_map(std::initializer_list<value_type> init, const Allocator& alloc = Allocator());
|
||||
|
||||
// (5)
|
||||
ordered_map(const ordered_map&) = default;
|
||||
|
||||
// (6)
|
||||
ordered_map(ordered_map&&) noexcept(std::is_nothrow_move_constructible<Container>::value) = default;
|
||||
```
|
||||
|
||||
1. Default constructor. Creates an empty `ordered_map`.
|
||||
2. Creates an empty `ordered_map` using the given allocator.
|
||||
3. Creates an `ordered_map` from the elements in range `[first, last)`, inserted in iteration order.
|
||||
4. Creates an `ordered_map` from an initializer list of key/value pairs, inserted in list order.
|
||||
5. Copy constructor.
|
||||
6. Move constructor.
|
||||
|
||||
These constructors are declared explicitly (rather than inherited via `#!cpp using Container::Container`)
|
||||
because older compilers (GCC <= 5.5, Xcode <= 9.4) do not handle the inherited constructors correctly.
|
||||
|
||||
## Template parameters
|
||||
|
||||
`It`
|
||||
: an input iterator type
|
||||
|
||||
## Parameters
|
||||
|
||||
`alloc` (in)
|
||||
: allocator to use for the underlying container
|
||||
|
||||
`first` (in)
|
||||
: iterator to the first element to insert
|
||||
|
||||
`last` (in)
|
||||
: iterator one past the last element to insert
|
||||
|
||||
`init` (in)
|
||||
: initializer list of key/value pairs to insert
|
||||
|
||||
## Complexity
|
||||
|
||||
1. Constant.
|
||||
2. Constant.
|
||||
3. Linear in the distance between `first` and `last`.
|
||||
4. Linear in the size of `init`.
|
||||
5. Linear in the size of `other`.
|
||||
6. Constant.
|
||||
|
||||
<!-- NOLINT Examples -->
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
@@ -1,17 +0,0 @@
|
||||
# <small>nlohmann::ordered_map::</small>~ordered_map
|
||||
|
||||
```cpp
|
||||
~ordered_map() = default;
|
||||
```
|
||||
|
||||
Destroys the `ordered_map` and frees all allocated memory.
|
||||
|
||||
## Complexity
|
||||
|
||||
Linear in the number of elements.
|
||||
|
||||
<!-- NOLINT Examples -->
|
||||
|
||||
## Version history
|
||||
|
||||
- Added in version 3.9.0 to implement [`nlohmann::ordered_json`](../ordered_json.md).
|
||||
@@ -1,21 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
int main()
|
||||
{
|
||||
// an empty binary value is encoded differently by the two drafts:
|
||||
// draft2 omits the optimized type marker for an empty byte array,
|
||||
// while draft3 always writes it
|
||||
json j = json::binary({});
|
||||
|
||||
// encode using BJData draft2 (the default)
|
||||
auto v_draft2 = json::to_bjdata(j, true, true, json::bjdata_version_t::draft2);
|
||||
|
||||
// encode using BJData draft3
|
||||
auto v_draft3 = json::to_bjdata(j, true, true, json::bjdata_version_t::draft3);
|
||||
|
||||
std::cout << "draft2 size: " << v_draft2.size() << '\n'
|
||||
<< "draft3 size: " << v_draft3.size() << std::endl;
|
||||
}
|
||||
@@ -1,2 +0,0 @@
|
||||
draft2 size: 4
|
||||
draft3 size: 6
|
||||
@@ -1,11 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using byte_container_with_subtype = nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>>;
|
||||
|
||||
int main()
|
||||
{
|
||||
std::cout << std::boolalpha
|
||||
<< std::is_same<byte_container_with_subtype::container_type, std::vector<std::uint8_t>>::value
|
||||
<< std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
true
|
||||
@@ -1,10 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using byte_container_with_subtype = nlohmann::byte_container_with_subtype<std::vector<std::uint8_t>>;
|
||||
|
||||
int main()
|
||||
{
|
||||
std::cout << std::boolalpha
|
||||
<< std::is_same<byte_container_with_subtype::subtype_type, std::uint64_t>::value << std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
true
|
||||
@@ -1,13 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
int main()
|
||||
{
|
||||
// an initializer_list_t is what a braced-init-list of JSON values is deduced as
|
||||
json::initializer_list_t init = {"a", 1, 2.0, false};
|
||||
|
||||
json j(init);
|
||||
std::cout << j.dump() << std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
["a",1,2.0,false]
|
||||
@@ -1,10 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
int main()
|
||||
{
|
||||
std::cout << std::boolalpha
|
||||
<< std::is_same<json::json_sax_t::binary_t, json::binary_t>::value << std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
true
|
||||
@@ -1,10 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
int main()
|
||||
{
|
||||
std::cout << std::boolalpha
|
||||
<< std::is_same<json::json_sax_t::number_float_t, json::number_float_t>::value << std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
true
|
||||
@@ -1,10 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
int main()
|
||||
{
|
||||
std::cout << std::boolalpha
|
||||
<< std::is_same<json::json_sax_t::number_integer_t, json::number_integer_t>::value << std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
true
|
||||
@@ -1,10 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
int main()
|
||||
{
|
||||
std::cout << std::boolalpha
|
||||
<< std::is_same<json::json_sax_t::number_unsigned_t, json::number_unsigned_t>::value << std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
true
|
||||
@@ -1,10 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
int main()
|
||||
{
|
||||
std::cout << std::boolalpha
|
||||
<< std::is_same<json::json_sax_t::string_t, json::string_t>::value << std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
true
|
||||
@@ -1,10 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
using json = nlohmann::json;
|
||||
|
||||
int main()
|
||||
{
|
||||
std::cout << std::boolalpha
|
||||
<< std::is_same<json::json_sax_t, nlohmann::json_sax<json>>::value << std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
true
|
||||
@@ -1,12 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
using Map = nlohmann::ordered_map<std::string, int>;
|
||||
|
||||
std::cout << std::boolalpha
|
||||
<< "Container is std::vector<std::pair<const Key, T>>: "
|
||||
<< std::is_same<Map::Container, std::vector<std::pair<const std::string, int>>>::value
|
||||
<< std::endl;
|
||||
}
|
||||
@@ -1 +0,0 @@
|
||||
Container is std::vector<std::pair<const Key, T>>: true
|
||||
@@ -1,26 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
nlohmann::ordered_map<std::string, int> m;
|
||||
m["one"] = 1;
|
||||
m["two"] = 2;
|
||||
|
||||
// access an existing element
|
||||
std::cout << "m.at(\"one\") = " << m.at("one") << std::endl;
|
||||
|
||||
// modify through the reference returned by at()
|
||||
m.at("two") = 22;
|
||||
std::cout << "m.at(\"two\") = " << m.at("two") << std::endl;
|
||||
|
||||
// accessing a missing key throws
|
||||
try
|
||||
{
|
||||
m.at("three");
|
||||
}
|
||||
catch (const std::out_of_range& e)
|
||||
{
|
||||
std::cout << "exception: " << e.what() << std::endl;
|
||||
}
|
||||
}
|
||||
@@ -1,3 +0,0 @@
|
||||
m.at("one") = 1
|
||||
m.at("two") = 22
|
||||
exception: key not found
|
||||
@@ -1,12 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
nlohmann::ordered_map<std::string, int> m;
|
||||
m["one"] = 1;
|
||||
|
||||
std::cout << std::boolalpha
|
||||
<< "m.count(\"one\") = " << m.count("one") << '\n'
|
||||
<< "m.count(\"two\") = " << m.count("two") << std::endl;
|
||||
}
|
||||
@@ -1,2 +0,0 @@
|
||||
m.count("one") = 1
|
||||
m.count("two") = 0
|
||||
@@ -1,15 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
nlohmann::ordered_map<std::string, std::string> m;
|
||||
|
||||
// emplace a new element
|
||||
auto res1 = m.emplace("one", "eins");
|
||||
std::cout << std::boolalpha << "inserted: " << res1.second << ", value: " << res1.first->second << std::endl;
|
||||
|
||||
// emplace with an already-existing key: no-op, returns the existing element
|
||||
auto res2 = m.emplace("one", "uno");
|
||||
std::cout << std::boolalpha << "inserted: " << res2.second << ", value: " << res2.first->second << std::endl;
|
||||
}
|
||||
@@ -1,2 +0,0 @@
|
||||
inserted: true, value: eins
|
||||
inserted: false, value: eins
|
||||
@@ -1,24 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
nlohmann::ordered_map<std::string, int> m;
|
||||
m["one"] = 1;
|
||||
m["two"] = 2;
|
||||
m["three"] = 3;
|
||||
|
||||
// erase by key
|
||||
std::size_t removed = m.erase("two");
|
||||
std::cout << "removed by key: " << removed << std::endl;
|
||||
|
||||
// erase by iterator
|
||||
m.erase(m.begin());
|
||||
|
||||
std::cout << "remaining: ";
|
||||
for (const auto& element : m)
|
||||
{
|
||||
std::cout << element.first << ' ';
|
||||
}
|
||||
std::cout << std::endl;
|
||||
}
|
||||
@@ -1,2 +0,0 @@
|
||||
removed by key: 1
|
||||
remaining: three
|
||||
@@ -1,19 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
nlohmann::ordered_map<std::string, int> m;
|
||||
m["one"] = 1;
|
||||
|
||||
auto it = m.find("one");
|
||||
if (it != m.end())
|
||||
{
|
||||
std::cout << "found: " << it->first << " = " << it->second << std::endl;
|
||||
}
|
||||
|
||||
if (m.find("two") == m.end())
|
||||
{
|
||||
std::cout << "\"two\" not found" << std::endl;
|
||||
}
|
||||
}
|
||||
@@ -1,2 +0,0 @@
|
||||
found: one = 1
|
||||
"two" not found
|
||||
@@ -1,21 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
nlohmann::ordered_map<std::string, int> m;
|
||||
|
||||
// insert a single value
|
||||
auto res = m.insert({"one", 1});
|
||||
std::cout << std::boolalpha << "inserted: " << res.second << std::endl;
|
||||
|
||||
// insert a range from another container
|
||||
std::vector<std::pair<const std::string, int>> more = {{"two", 2}, {"three", 3}};
|
||||
m.insert(more.begin(), more.end());
|
||||
|
||||
for (const auto& element : m)
|
||||
{
|
||||
std::cout << element.first << ':' << element.second << ' ';
|
||||
}
|
||||
std::cout << std::endl;
|
||||
}
|
||||
@@ -1,2 +0,0 @@
|
||||
inserted: true
|
||||
one:1 two:2 three:3
|
||||
@@ -1,12 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
using Map = nlohmann::ordered_map<std::string, int>;
|
||||
Map::key_compare compare{};
|
||||
|
||||
std::cout << std::boolalpha
|
||||
<< "compare(\"a\", \"a\") = " << compare("a", "a") << '\n'
|
||||
<< "compare(\"a\", \"b\") = " << compare("a", "b") << std::endl;
|
||||
}
|
||||
@@ -1,2 +0,0 @@
|
||||
compare("a", "a") = true
|
||||
compare("a", "b") = false
|
||||
@@ -1,14 +0,0 @@
|
||||
#include <iostream>
|
||||
#include <nlohmann/json.hpp>
|
||||
|
||||
int main()
|
||||
{
|
||||
nlohmann::ordered_map<std::string, int> m;
|
||||
|
||||
// operator[] inserts a default-constructed value if the key doesn't exist yet
|
||||
m["one"] = 1;
|
||||
std::cout << "m[\"one\"] = " << m["one"] << std::endl;
|
||||
|
||||
// accessing again just returns the existing value
|
||||
std::cout << "m[\"one\"] = " << m["one"] << std::endl;
|
||||
}
|
||||
@@ -1,2 +0,0 @@
|
||||
m["one"] = 1
|
||||
m["one"] = 1
|
||||
@@ -174,6 +174,13 @@ security reasons (e.g., Intel Software Guard Extensions (SGX)).
|
||||
|
||||
See [full documentation of `JSON_NO_IO`](../api/macros/json_no_io.md).
|
||||
|
||||
## `JSON_NO_SIMD`
|
||||
|
||||
When defined, the library uses only portable code instead of vector instructions (SSE2, SSSE3, NEON) for scanning
|
||||
strings and writing floating-point numbers. Results are the same either way. It is not defined by default.
|
||||
|
||||
See [full documentation of `JSON_NO_SIMD`](../api/macros/json_no_simd.md).
|
||||
|
||||
## `JSON_NO_THREAD_LOCAL`
|
||||
|
||||
When defined, the library does not use `#!cpp thread_local` storage. Copying a value and comparing two values then
|
||||
|
||||
@@ -27,6 +27,7 @@ The complete default namespace name is derived as follows:
|
||||
`_dsbs`.
|
||||
- [`JSON_DISABLE_UNLOCKED_FILE_IO`](../api/macros/json_disable_unlocked_file_io.md) defined non-zero appends
|
||||
`_dufio`.
|
||||
- [`JSON_NO_SIMD`](../api/macros/json_no_simd.md) defined appends `_ns`.
|
||||
- [`JSON_VIEW_NO_SIMD`](../api/macros/json_view_no_simd.md) defined appends `_vns`.
|
||||
- [`JSON_VIEW_USE_SSSE3`](../api/macros/json_view_use_ssse3.md) defined appends `_vssse3`.
|
||||
- The inline namespace ends with the suffix `_v` followed by the 3 components of the version number separated by
|
||||
@@ -114,6 +115,7 @@ follows:
|
||||
([`JSON_STRICT_BINARY_UTF8`](../api/macros/json_strict_binary_utf8.md)), `_ekmo`
|
||||
([`JSON_USE_OBJECTS_FOR_ENUM_KEYED_MAPS`](../api/macros/json_use_objects_for_enum_keyed_maps.md)), `_dsbs`
|
||||
([`JSON_DISABLE_STREAM_BULK_SCAN`](../api/macros/json_disable_stream_bulk_scan.md)), `_dufio`
|
||||
([`JSON_DISABLE_UNLOCKED_FILE_IO`](../api/macros/json_disable_unlocked_file_io.md)), `_vns`
|
||||
([`JSON_DISABLE_UNLOCKED_FILE_IO`](../api/macros/json_disable_unlocked_file_io.md)), `_ns`
|
||||
([`JSON_NO_SIMD`](../api/macros/json_no_simd.md)), `_vns`
|
||||
([`JSON_VIEW_NO_SIMD`](../api/macros/json_view_no_simd.md)), and `_vssse3`
|
||||
([`JSON_VIEW_USE_SSSE3`](../api/macros/json_view_use_ssse3.md)) in version 3.13.0.
|
||||
@@ -51,16 +51,16 @@ If you do want to preserve the **insertion order**, you can use the type [`nlohm
|
||||
--8<-- "examples/ordered_json.output"
|
||||
```
|
||||
|
||||
Alternatively, [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) also preserves the insertion order and, unlike [`ordered_map`](../api/ordered_map/index.md), keeps a lookup index, so it does not have the quadratic cost described below. It is used through a small adapter ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).
|
||||
Alternatively, [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) also preserves the insertion order and, unlike [`ordered_map`](../api/ordered_map.md), keeps a lookup index, so it does not have the quadratic cost described below. It is used through a small adapter ([integration](https://github.com/nlohmann/json/issues/485#issuecomment-333652309)).
|
||||
|
||||
If the order does not matter and you only want faster lookup, `boost::unordered_flat_map`, `absl::flat_hash_map`, `absl::node_hash_map`, and several other hash maps work through an adapter that restores the template argument order `basic_json` expects; see [Template Parameter Requirements](types/template_parameters.md#objecttype). Note these are *unordered*, not insertion-ordered.
|
||||
|
||||
[`tsl::ordered_map`](https://github.com/Tessil/ordered-map) cannot be used: its iterators expose the mapped value as `const`, while `basic_json` needs to modify it in place.
|
||||
|
||||
The [`ordered_map`](../api/ordered_map/index.md) behind `nlohmann::ordered_json` is deliberately minimal and has no lookup
|
||||
The [`ordered_map`](../api/ordered_map.md) behind `nlohmann::ordered_json` is deliberately minimal and has no lookup
|
||||
index, so every key access is a linear scan and building an object of `n` keys costs O(n²). This is unnoticeable at
|
||||
typical object sizes but becomes significant for objects with many thousands of keys; see
|
||||
[`ordered_map` complexity](../api/ordered_map/index.md#complexity). The alternatives above keep a lookup index and do not
|
||||
[`ordered_map` complexity](../api/ordered_map.md#complexity). The alternatives above keep a lookup index and do not
|
||||
have this cost.
|
||||
|
||||
### Notes on parsing
|
||||
|
||||
@@ -79,6 +79,10 @@ follow the usual `std::streambuf` contract, and
|
||||
[`JSON_DISABLE_UNLOCKED_FILE_IO`](../../api/macros/json_disable_unlocked_file_io.md) for programs in which another
|
||||
thread must use the same `#!cpp FILE` object while it is parsed.
|
||||
|
||||
Where the target has them, strings are scanned with vector instructions: SSE2 on x86-64 (and SSSE3 for UTF-8 text, when
|
||||
the CPU has it) and NEON on AArch64. [`JSON_NO_SIMD`](../../api/macros/json_no_simd.md) selects portable code instead,
|
||||
again without changing any result.
|
||||
|
||||
## SAX vs. DOM parsing
|
||||
|
||||
The library offers two parsing models:
|
||||
|
||||
@@ -20,32 +20,39 @@ below apply on every supported standard. This adapter exposes two optimizations
|
||||
|
||||
- it can reconstruct already-consumed input on demand for error messages, instead of copying every character as it is
|
||||
read, and
|
||||
- the lexer can scan ordinary string characters directly out of the buffer, several bytes at a time, rather than one
|
||||
character (and one function call) at a time.
|
||||
- the lexer can scan ordinary string characters, numbers, and indentation directly out of the buffer, several bytes at
|
||||
a time, rather than one character (and one function call) at a time.
|
||||
|
||||
A `#!cpp std::istream` (including `#!cpp std::ifstream`) or `#!cpp FILE*`, by contrast, is read through
|
||||
`input_stream_adapter` or `file_input_adapter`, which read one character (or one block, for binary formats) at a time
|
||||
and expose neither optimization -- the lexer falls back to the same byte-at-a-time path it uses for any
|
||||
non-contiguous, general-purpose iterator range. An iterator pair over non-contiguous but random-access storage (e.g.
|
||||
`#!cpp std::deque<char>::iterator`) gets the first optimization but not the second, since the byte-scanning fast path
|
||||
additionally requires contiguous storage.
|
||||
A `#!cpp std::istream` (including `#!cpp std::ifstream`) gets the same bulk scanning: `input_stream_adapter` scans the
|
||||
characters its stream buffer already holds (the *get area*) and asks the stream buffer for more only when they are used
|
||||
up. Nothing is read ahead, so the stream is left exactly where it would be after reading one character at a time, and
|
||||
[`operator>>`](../api/operator_gtgt.md) can still read several values from one stream. A stream buffer without a get
|
||||
area is read one character at a time. A `#!cpp FILE*` is still read one character at a time, but `file_input_adapter`
|
||||
locks the file once per parse instead of once per character. See
|
||||
[input sources and performance](parsing/index.md#input-sources-and-performance) for the full table. According to the
|
||||
description of [#5828](https://github.com/nlohmann/json/pull/5828), parsing from a stream is within about 10 to 20 % of
|
||||
parsing an equivalent `#!cpp std::string`.
|
||||
|
||||
Practically: if the JSON text is already in memory, or small enough to read into memory, prefer passing a
|
||||
`#!cpp std::string`, a `#!cpp std::vector<char>`, or a pointer range to `parse` over a `#!cpp std::istream`. For a
|
||||
file, that means reading it into a string first and then parsing the string, rather than passing a
|
||||
`#!cpp std::ifstream` directly to `parse` -- the latter never benefits from either optimization:
|
||||
Inputs that are still read one character at a time: iterator ranges that are not contiguous (e.g.
|
||||
`#!cpp std::list<char>` or `#!cpp std::istreambuf_iterator<char>`), wide strings, and user-defined adapters. An
|
||||
iterator pair over non-contiguous but random-access storage (e.g. `#!cpp std::deque<char>::iterator`) gets the first
|
||||
optimization but not the second, since the byte-scanning fast path requires contiguous storage.
|
||||
|
||||
Practically: a file can be passed directly to `parse`, which also avoids the memory for a copy of the file. Reading it
|
||||
into a string first is no longer necessary for speed:
|
||||
|
||||
```cpp
|
||||
// gets the contiguous fast paths
|
||||
// fast: the stream buffer's get area is scanned in bulk
|
||||
std::ifstream f("example.json");
|
||||
std::string contents((std::istreambuf_iterator<char>(f)), std::istreambuf_iterator<char>());
|
||||
json j = json::parse(contents);
|
||||
|
||||
// does not: input_stream_adapter has no fast path
|
||||
std::ifstream f2("example.json");
|
||||
json j2 = json::parse(f2);
|
||||
json j = json::parse(f);
|
||||
```
|
||||
|
||||
Two macros switch the stream optimizations off without changing any result:
|
||||
[`JSON_DISABLE_STREAM_BULK_SCAN`](../api/macros/json_disable_stream_bulk_scan.md) for stream buffers that do not follow
|
||||
the usual `#!cpp std::streambuf` contract, and
|
||||
[`JSON_DISABLE_UNLOCKED_FILE_IO`](../api/macros/json_disable_unlocked_file_io.md) for programs in which another thread
|
||||
must use the same `#!cpp FILE` object while it is parsed.
|
||||
|
||||
For contiguous input with many non-ASCII characters, [`JSON_USE_SIMDUTF`](../api/macros/json_use_simdutf.md) can
|
||||
additionally speed up UTF-8 validation by using the [simdutf](https://github.com/simdutf/simdutf) library instead of
|
||||
the built-in scalar validator; streaming inputs (files, `#!cpp std::istream`, wide strings, user-defined adapters)
|
||||
@@ -94,10 +101,10 @@ whether it is worth the loss of human readability at all -- depends on the actua
|
||||
The default [`json`](../api/json.md) type stores object keys in a `#!cpp std::map`, giving logarithmic-time lookup,
|
||||
insertion, and erasure, at the cost of sorting keys alphabetically rather than preserving insertion order (see
|
||||
[Object Order](object_order.md)). [`ordered_json`](../api/ordered_json.md) uses
|
||||
[`nlohmann::ordered_map`](../api/ordered_map/index.md) instead, a `#!cpp std::vector`-backed container with no lookup index:
|
||||
[`nlohmann::ordered_map`](../api/ordered_map.md) instead, a `#!cpp std::vector`-backed container with no lookup index:
|
||||
every key-based operation is a **linear scan**, so building an object of `n` distinct keys costs **O(n²)** in total --
|
||||
this applies equally to inserting keys one by one and to parsing an object, since the parser inserts each key as it is
|
||||
read. The [measurements on the `ordered_map` page](../api/ordered_map/index.md#complexity) show this is
|
||||
read. The [measurements on the `ordered_map` page](../api/ordered_map.md#complexity) show this is
|
||||
negligible at typical object sizes (2000 keys: 0.7 ms for `json` vs. 3.6 ms for `ordered_json`, a 5x factor) but grows
|
||||
steeply for large, machine-generated objects (16 000 keys: 3.3 ms vs. 181.6 ms, a 54x factor).
|
||||
|
||||
|
||||
@@ -42,7 +42,7 @@ Requirements are split into two groups:
|
||||
|
||||
| Template parameter | Default | Notable substitutes |
|
||||
|-------------------------------------------------------------------|-----------------------------------|--------------------------------------------------------------------------------------------------|
|
||||
| [`ObjectType`](#objecttype) | `std::map` | [`nlohmann::ordered_map`](../../api/ordered_map/index.md), Abseil hash maps |
|
||||
| [`ObjectType`](#objecttype) | `std::map` | [`nlohmann::ordered_map`](../../api/ordered_map.md), Abseil hash maps |
|
||||
| [`ArrayType`](#arraytype) | `std::vector` | `#!cpp std::deque` |
|
||||
| [`StringType`](#stringtype) | `std::string` | `std::string`-like types over `char` |
|
||||
| [`BooleanType`](#booleantype) | `bool` | none worth using |
|
||||
@@ -235,7 +235,7 @@ The library does not sort or de-duplicate keys itself; the behavior described in
|
||||
| Container | Notes |
|
||||
|----------------------------------------------------------------------------------|-------------------------------------------------------------------------------|
|
||||
| `#!cpp std::map` (default) | |
|
||||
| [`nlohmann::ordered_map`](../../api/ordered_map/index.md) | used by [`ordered_json`](../../api/ordered_json.md); keeps insertion order |
|
||||
| [`nlohmann::ordered_map`](../../api/ordered_map.md) | used by [`ordered_json`](../../api/ordered_json.md); keeps insertion order |
|
||||
| [`nlohmann::fifo_map`](https://github.com/nlohmann/fifo_map) | keeps insertion order; adapter puts `fifo_map_compare` in the comparator slot |
|
||||
| `boost::container::map`, `boost::container::flat_map` | no adapter needed |
|
||||
| `#!cpp std::unordered_map` | through the adapter above; not with libstdc++ 9, see the note |
|
||||
|
||||
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