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Author SHA1 Message Date
Niels Lohmann 14558ba011 Merge branch 'develop' into claude/issue-5066-24ba30
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-28 22:22:36 +02:00
Niels Lohmann ccb419ca64 Fix clang-tidy and clang 6 in the #5066 regression test
ci_clang_tidy asked for emplace_back instead of push_back. The
push_back is the point of the test: #5066 is about the implicit
conversion from json to the vector's value type, which emplace_back
would bypass. Silence the check on that line.

clang 5 and 6 cannot instantiate std::variant<json> from libstdc++ 10's
<variant> ("cannot cast private base class"), which broke
ci_test_compilers_clang (6). Tested with the CI images: clang 7 to 11
compile and pass, including clang 11 with libstdc++ 10. Skip the runtime
check for clang before 7; the static_assert still runs.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-28 18:22:16 +02:00
Niels Lohmann 4494890be6 Merge branch 'develop' into claude/issue-5066-24ba30
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-27 20:57:55 +02:00
Niels Lohmann c4469c9f82 Add regression test for converting json to std::variant<json> (#5066)
With 3.10.5, get<std::variant<json>>() was well-formed through the string
from_json overload, so the implicit conversion operator was a candidate
when converting json to std::variant<json>, and MSVC picked it over the
variant's converting constructor. The tightened constraints from #3427 and
#3604 (3.11.0) removed that path; this test guards against regressions.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-27 16:49:33 +02:00
156 changed files with 395 additions and 12505 deletions
-17
View File
@@ -45,23 +45,6 @@ labels:
- label: "aspect: binary formats"
title: "(?i)(bson|cbor|msgpack|messagepack|ubjson|bjdata|bon8|binary format)"
- label: "aspect: json_view"
files:
- "include/nlohmann/json_view\\.hpp"
- "include/nlohmann/detail/view/.*"
- "single_include/nlohmann/json_view\\.hpp"
- "tests/src/unit-json_view.*"
- "tests/src/fuzzer-parse_json_view\\.cpp"
- "tools/amalgamate/config_json_view\\.json"
- "docs/mkdocs/docs/features/json_view\\.md"
- "docs/mkdocs/docs/api/basic_json_(document|view)/.*"
- "docs/mkdocs/docs/api/(ordered_)?json_(document|view)\\.md"
- "docs/mkdocs/docs/examples/(basic_json_(document|view)__|(ordered_)?json_(document|view)).*"
- "tests/benchmarks/src/benchmarks_view\\.cpp"
- label: "aspect: json_view"
title: "(?i)(json_view|json_document|zero-copy)"
- label: "python"
files:
- "\\.py$"
+1 -2
View File
@@ -67,13 +67,12 @@ jobs:
python3 $TOOL_DIR/amalgamate.py -c $TOOL_DIR/config_json.json -s .
python3 $TOOL_DIR/amalgamate.py -c $TOOL_DIR/config_json_fwd.json -s .
python3 $TOOL_DIR/amalgamate.py -c $TOOL_DIR/config_json_view.json -s .
# the header list of the Bazel "json" target must match the files in include/
cmake -P cmake/scripts/gen_bazel_build_file.cmake
${{ github.workspace }}/venv/bin/astyle --project=tools/astyle/.astylerc --suffix=none --quiet \
$INCLUDE_DIR/json.hpp $INCLUDE_DIR/json_fwd.hpp $INCLUDE_DIR/json_view.hpp
$INCLUDE_DIR/json.hpp $INCLUDE_DIR/json_fwd.hpp
# fail loudly if a directory is renamed or removed: find would only warn
# about the missing path and silently drop its files from the check
-16
View File
@@ -20,9 +20,7 @@ cc_library(
hdrs = [
"include/nlohmann/adl_serializer.hpp",
"include/nlohmann/byte_container_with_subtype.hpp",
"include/nlohmann/detail/abi_config.hpp",
"include/nlohmann/detail/abi_macros.hpp",
"include/nlohmann/detail/bit_ops.hpp",
"include/nlohmann/detail/conversions/from_json.hpp",
"include/nlohmann/detail/conversions/to_chars.hpp",
"include/nlohmann/detail/conversions/to_json.hpp",
@@ -35,7 +33,6 @@ cc_library(
"include/nlohmann/detail/input/number_parse.hpp",
"include/nlohmann/detail/input/parser.hpp",
"include/nlohmann/detail/input/position_t.hpp",
"include/nlohmann/detail/input/pow5_table.hpp",
"include/nlohmann/detail/input/string_scan.hpp",
"include/nlohmann/detail/iterators/internal_iterator.hpp",
"include/nlohmann/detail/iterators/iter_impl.hpp",
@@ -66,20 +63,8 @@ cc_library(
"include/nlohmann/detail/string_escape.hpp",
"include/nlohmann/detail/string_utils.hpp",
"include/nlohmann/detail/value_t.hpp",
"include/nlohmann/detail/view/builder.hpp",
"include/nlohmann/detail/view/document_data.hpp",
"include/nlohmann/detail/view/errors.hpp",
"include/nlohmann/detail/view/input.hpp",
"include/nlohmann/detail/view/macro_scope.hpp",
"include/nlohmann/detail/view/macro_unscope.hpp",
"include/nlohmann/detail/view/materialize.hpp",
"include/nlohmann/detail/view/node.hpp",
"include/nlohmann/detail/view/number.hpp",
"include/nlohmann/detail/view/scan.hpp",
"include/nlohmann/detail/view/string_ref.hpp",
"include/nlohmann/json.hpp",
"include/nlohmann/json_fwd.hpp",
"include/nlohmann/json_view.hpp",
"include/nlohmann/ordered_map.hpp",
"include/nlohmann/thirdparty/hedley/hedley.hpp",
"include/nlohmann/thirdparty/hedley/hedley_undef.hpp",
@@ -92,7 +77,6 @@ cc_library(
name = "singleheader-json",
hdrs = [
"single_include/nlohmann/json.hpp",
"single_include/nlohmann/json_view.hpp",
],
includes = ["single_include"],
visibility = ["//visibility:public"],
+6 -25
View File
@@ -21,7 +21,6 @@ TESTS_SRCS=$(shell find tests -type f \( -name '*.hpp' -o -name '*.cpp' -o -name
# the single headers (amalgamated from the source files)
AMALGAMATED_FILE=single_include/nlohmann/json.hpp
AMALGAMATED_FWD_FILE=single_include/nlohmann/json_fwd.hpp
AMALGAMATED_VIEW_FILE=single_include/nlohmann/json_view.hpp
##########################################################################
@@ -30,7 +29,7 @@ AMALGAMATED_VIEW_FILE=single_include/nlohmann/json_view.hpp
# main target
all:
@echo "amalgamate - amalgamate files single_include/nlohmann/json{,_fwd,_view}.hpp from the include/nlohmann sources"
@echo "amalgamate - amalgamate files single_include/nlohmann/json{,_fwd}.hpp from the include/nlohmann sources"
@echo "BUILD.bazel - regenerate the Bazel BUILD file from the include/nlohmann sources"
@echo "ChangeLog.md - generate ChangeLog file"
@echo "check-amalgamation - check whether sources have been amalgamated and BUILD.bazel is up to date"
@@ -40,7 +39,6 @@ all:
@echo "fuzz_testing_bon8 - prepare fuzz testing of the BON8 parser"
@echo "fuzz_testing_bson - prepare fuzz testing of the BSON parser"
@echo "fuzz_testing_cbor - prepare fuzz testing of the CBOR parser"
@echo "fuzz_testing_json_view - prepare fuzz testing of the json_document/json_view parser"
@echo "fuzz_testing_msgpack - prepare fuzz testing of the MessagePack parser"
@echo "fuzz_testing_ubjson - prepare fuzz testing of the UBJSON parser"
@echo "pretty - beautify code with Artistic Style"
@@ -98,14 +96,6 @@ fuzz_testing_cbor:
find tests/data -size -5k -name *.cbor | xargs -I{} cp "{}" fuzz-testing/testcases
@echo "Execute: afl-fuzz -i fuzz-testing/testcases -o fuzz-testing/out fuzz-testing/fuzzer"
fuzz_testing_json_view:
rm -fr fuzz-testing
mkdir -p fuzz-testing fuzz-testing/testcases fuzz-testing/out
$(MAKE) parse_json_view_fuzzer -C tests CXX=afl-clang++
mv tests/parse_json_view_fuzzer fuzz-testing/fuzzer
find tests/data/json_tests -size -5k -name *json | xargs -I{} cp "{}" fuzz-testing/testcases
@echo "Execute: afl-fuzz -i fuzz-testing/testcases -o fuzz-testing/out fuzz-testing/fuzzer"
fuzz_testing_msgpack:
rm -fr fuzz-testing
mkdir -p fuzz-testing fuzz-testing/testcases fuzz-testing/out
@@ -164,14 +154,14 @@ install_astyle:
# call the Artistic Style pretty printer on all source files
pretty: install_astyle
$(ASTYLE) --project=tools/astyle/.astylerc $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_VIEW_FILE) docs/mkdocs/docs/examples/*.cpp
$(ASTYLE) --project=tools/astyle/.astylerc $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) docs/mkdocs/docs/examples/*.cpp
# call the Clang-Format on all source files
pretty_format:
for FILE in $(SRCS) $(TESTS_SRCS) $(AMALGAMATED_FILE) docs/mkdocs/docs/examples/*.cpp; do echo $$FILE; clang-format -i $$FILE; done
# create single header files and pretty print
amalgamate: $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_VIEW_FILE)
amalgamate: $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE)
$(MAKE) pretty
# call the amalgamation tool for json.hpp
@@ -182,23 +172,16 @@ $(AMALGAMATED_FILE): $(SRCS)
$(AMALGAMATED_FWD_FILE): $(SRCS)
tools/amalgamate/amalgamate.py -c tools/amalgamate/config_json_fwd.json -s . --verbose=yes
# call the amalgamation tool for json_view.hpp (keeps including json.hpp)
$(AMALGAMATED_VIEW_FILE): $(SRCS)
tools/amalgamate/amalgamate.py -c tools/amalgamate/config_json_view.json -s . --verbose=yes
# check if file single_include/nlohmann/json.hpp has been amalgamated from the nlohmann sources
# Note: this target is called by Travis
check-amalgamation:
@mv $(AMALGAMATED_FILE) $(AMALGAMATED_FILE)~
@mv $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_FWD_FILE)~
@mv $(AMALGAMATED_VIEW_FILE) $(AMALGAMATED_VIEW_FILE)~
@$(MAKE) amalgamate
@diff $(AMALGAMATED_FILE) $(AMALGAMATED_FILE)~ || (echo "===================================================================\n Amalgamation required! Please read the contribution guidelines\n in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_FILE)~ $(AMALGAMATED_FILE) ; false)
@diff $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_FWD_FILE)~ || (echo "===================================================================\n Amalgamation required! Please read the contribution guidelines\n in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_FWD_FILE)~ $(AMALGAMATED_FWD_FILE) ; false)
@diff $(AMALGAMATED_VIEW_FILE) $(AMALGAMATED_VIEW_FILE)~ || (echo "===================================================================\n Amalgamation required! Please read the contribution guidelines\n in file .github/CONTRIBUTING.md.\n===================================================================" ; mv $(AMALGAMATED_VIEW_FILE)~ $(AMALGAMATED_VIEW_FILE) ; false)
@mv $(AMALGAMATED_FILE)~ $(AMALGAMATED_FILE)
@mv $(AMALGAMATED_FWD_FILE)~ $(AMALGAMATED_FWD_FILE)
@mv $(AMALGAMATED_VIEW_FILE)~ $(AMALGAMATED_VIEW_FILE)
@mv BUILD.bazel BUILD.bazel~
@$(MAKE) BUILD.bazel
@diff BUILD.bazel BUILD.bazel~ || (echo "===================================================================\n BUILD.bazel is out of date! Please run 'make BUILD.bazel'.\n===================================================================" ; mv BUILD.bazel~ BUILD.bazel ; false)
@@ -239,7 +222,7 @@ json.tar.xz:
# We use `-X` to make the resulting ZIP file reproducible, see
# <https://content.pivotal.io/blog/barriers-to-deterministic-reproducible-zip-files>.
include.zip: BUILD.bazel
zip -9 --recurse-paths -X include.zip $(SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) $(AMALGAMATED_VIEW_FILE) BUILD.bazel MODULE.bazel meson.build LICENSE.MIT
zip -9 --recurse-paths -X include.zip $(SRCS) $(AMALGAMATED_FILE) $(AMALGAMATED_FWD_FILE) BUILD.bazel MODULE.bazel meson.build LICENSE.MIT
# Create the files for a release and add signatures and hashes.
release: include.zip json.tar.xz
@@ -248,13 +231,11 @@ release: include.zip json.tar.xz
gpg --armor --detach-sig include.zip
gpg --armor --detach-sig $(AMALGAMATED_FILE)
gpg --armor --detach-sig $(AMALGAMATED_FWD_FILE)
gpg --armor --detach-sig $(AMALGAMATED_VIEW_FILE)
gpg --armor --detach-sig json.tar.xz
cp $(AMALGAMATED_FILE) release_files
cp $(AMALGAMATED_FWD_FILE) release_files
cp $(AMALGAMATED_VIEW_FILE) release_files
mv $(AMALGAMATED_FILE).asc $(AMALGAMATED_FWD_FILE).asc $(AMALGAMATED_VIEW_FILE).asc json.tar.xz json.tar.xz.asc include.zip include.zip.asc release_files
cd release_files ; shasum -a 256 json.hpp json_view.hpp include.zip json.tar.xz > hashes.txt
mv $(AMALGAMATED_FILE).asc $(AMALGAMATED_FWD_FILE).asc json.tar.xz json.tar.xz.asc include.zip include.zip.asc release_files
cd release_files ; shasum -a 256 json.hpp include.zip json.tar.xz > hashes.txt
##########################################################################
-10
View File
@@ -1189,14 +1189,6 @@ binary.set_subtype(0x10);
auto cbor = json::to_msgpack(j); // 0xD5 (fixext2), 0x10, 0xCA, 0xFE
```
### Zero-copy views
Header `<nlohmann/json_view.hpp>` adds `json_document`/`json_view`, a read-only, non-owning way to look at a parsed
JSON text: parsing builds a flat index (16 bytes per value) instead of a tree, strings and numbers stay in the source
text, and `materialize()` builds a `json` value for a subtree only when you actually need one. See
[Zero-copy JSON views](https://json.nlohmann.me/features/json_view/) for the details, including which inputs are
borrowed and which are copied.
## Customers
The library is used in multiple projects, applications, operating systems, etc. The list below is not exhaustive, but the result of an internet search. If you know further customers of the library, please let me know, see [contact](#contact).
@@ -1403,8 +1395,6 @@ THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR I
- The class contains a slightly modified version of the Grisu2 algorithm from Florian Loitsch which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above). Copyright &copy; 2009 [Florian Loitsch](https://florian.loitsch.com/)
- The class contains a copy of [Hedley](https://nemequ.github.io/hedley/) from Evan Nemerson which is licensed as [CC0-1.0](https://creativecommons.org/publicdomain/zero/1.0/).
- The class contains parts of [Google Abseil](https://github.com/abseil/abseil-cpp) which is licensed under the [Apache 2.0 License](https://opensource.org/licenses/Apache-2.0).
- The class contains an adapted version of the Eisel-Lemire algorithm and its table of powers of five from [fast_float](https://github.com/fastfloat/fast_float) by Daniel Lemire and contributors, which is available under the [MIT License](https://opensource.org/licenses/MIT) (used here), the Apache 2.0 License, and the Boost Software License. Copyright &copy; 2021 The fast_float authors
- The view's parser (`<nlohmann/json_view.hpp>`) contains techniques and code adapted from [yyjson](https://github.com/ibireme/yyjson) by YaoYuan, which is licensed under the [MIT License](https://opensource.org/licenses/MIT) (see above): table-driven decoding of `\u` escapes and fixed-offset unrolled checks.
<img align="right" src="https://git.fsfe.org/reuse/reuse-ci/raw/branch/master/reuse-horizontal.png" alt="REUSE Software">
+2 -5
View File
@@ -373,10 +373,9 @@ file(GLOB_RECURSE INDENT_FILES
set(include_dir ${PROJECT_SOURCE_DIR}/single_include/nlohmann)
set(tool_dir ${PROJECT_SOURCE_DIR}/tools/amalgamate)
add_custom_target(ci_test_amalgamation
COMMAND rm -fr ${include_dir}/json.hpp~ ${include_dir}/json_fwd.hpp~ ${include_dir}/json_view.hpp~
COMMAND rm -fr ${include_dir}/json.hpp~ ${include_dir}/json_fwd.hpp~
COMMAND cp ${include_dir}/json.hpp ${include_dir}/json.hpp~
COMMAND cp ${include_dir}/json_fwd.hpp ${include_dir}/json_fwd.hpp~
COMMAND cp ${include_dir}/json_view.hpp ${include_dir}/json_view.hpp~
COMMAND ${Python3_EXECUTABLE} -mvenv venv_astyle
COMMAND venv_astyle/bin/pip3 --quiet install -r ${CMAKE_SOURCE_DIR}/tools/astyle/requirements.txt
@@ -384,12 +383,10 @@ add_custom_target(ci_test_amalgamation
COMMAND ${Python3_EXECUTABLE} ${tool_dir}/amalgamate.py -c ${tool_dir}/config_json.json -s .
COMMAND ${Python3_EXECUTABLE} ${tool_dir}/amalgamate.py -c ${tool_dir}/config_json_fwd.json -s .
COMMAND ${Python3_EXECUTABLE} ${tool_dir}/amalgamate.py -c ${tool_dir}/config_json_view.json -s .
COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=none ${include_dir}/json.hpp ${include_dir}/json_fwd.hpp ${include_dir}/json_view.hpp
COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=none ${include_dir}/json.hpp ${include_dir}/json_fwd.hpp
COMMAND diff ${include_dir}/json.hpp~ ${include_dir}/json.hpp
COMMAND diff ${include_dir}/json_fwd.hpp~ ${include_dir}/json_fwd.hpp
COMMAND diff ${include_dir}/json_view.hpp~ ${include_dir}/json_view.hpp
COMMAND venv_astyle/bin/astyle --project=tools/astyle/.astylerc --suffix=orig ${INDENT_FILES}
COMMAND for FILE in `find . -name '*.orig'`\; do false \; done
-1
View File
@@ -48,7 +48,6 @@ cc_library(
name = "singleheader-json",
hdrs = [
"single_include/nlohmann/json.hpp",
"single_include/nlohmann/json_view.hpp",
],
includes = ["single_include"],
visibility = ["//visibility:public"],
-39
View File
@@ -128,43 +128,7 @@ INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::to_ubjson', 'Func
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::value', 'Method', 'api/basic_json/value/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::value_t', 'Enum', 'api/basic_json/value_t/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json::~basic_json', 'Method', 'api/basic_json/~basic_json/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document', 'Class', 'api/basic_json_document/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::basic_json_document', 'Constructor', 'api/basic_json_document/basic_json_document/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::accept', 'Function', 'api/basic_json_document/accept/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::is_discarded', 'Method', 'api/basic_json_document/is_discarded/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::memory_usage', 'Method', 'api/basic_json_document/memory_usage/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::node_count', 'Method', 'api/basic_json_document/node_count/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::owns_source', 'Method', 'api/basic_json_document/owns_source/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::parse', 'Function', 'api/basic_json_document/parse/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::parse_copy', 'Function', 'api/basic_json_document/parse_copy/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::read', 'Method', 'api/basic_json_document/read/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::root', 'Method', 'api/basic_json_document/root/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::shrink_to_fit', 'Method', 'api/basic_json_document/shrink_to_fit/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_document::source', 'Method', 'api/basic_json_document/source/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view', 'Class', 'api/basic_json_view/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::basic_json_view', 'Constructor', 'api/basic_json_view/basic_json_view/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::empty', 'Method', 'api/basic_json_view/empty/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_array', 'Method', 'api/basic_json_view/is_array/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_binary', 'Method', 'api/basic_json_view/is_binary/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_boolean', 'Method', 'api/basic_json_view/is_boolean/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_discarded', 'Method', 'api/basic_json_view/is_discarded/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_null', 'Method', 'api/basic_json_view/is_null/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_number', 'Method', 'api/basic_json_view/is_number/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_number_float', 'Method', 'api/basic_json_view/is_number_float/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_number_integer', 'Method', 'api/basic_json_view/is_number_integer/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_number_unsigned', 'Method', 'api/basic_json_view/is_number_unsigned/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_object', 'Method', 'api/basic_json_view/is_object/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_primitive', 'Method', 'api/basic_json_view/is_primitive/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_string', 'Method', 'api/basic_json_view/is_string/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::is_structured', 'Method', 'api/basic_json_view/is_structured/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::materialize', 'Method', 'api/basic_json_view/materialize/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::operator bool', 'Method', 'api/basic_json_view/operator_bool/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::size', 'Method', 'api/basic_json_view/size/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::source_offset', 'Method', 'api/basic_json_view/source_offset/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('basic_json_view::type', 'Method', 'api/basic_json_view/type/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json', 'Class', 'api/json/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_document', 'Class', 'api/json_document/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_view', 'Class', 'api/json_view/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer', 'Class', 'api/json_pointer/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::back', 'Method', 'api/json_pointer/back/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('json_pointer::empty', 'Method', 'api/json_pointer/empty/index.html');
@@ -198,8 +162,6 @@ INSERT INTO searchIndex(name, type, path) VALUES ('operator""_json_pointer', 'Li
INSERT INTO searchIndex(name, type, path) VALUES ('operator<<', 'Operator', 'api/operator_ltlt/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('operator>>', 'Operator', 'api/operator_gtgt/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json', 'Class', 'api/ordered_json/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_document', 'Class', 'api/ordered_json_document/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('ordered_json_view', 'Class', 'api/ordered_json_view/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('ordered_map', 'Class', 'api/ordered_map/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('std::hash<basic_json>', 'Class', 'api/basic_json/std_hash/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('std::swap<basic_json>', 'Function', 'api/basic_json/std_swap/index.html');
@@ -229,7 +191,6 @@ INSERT INTO searchIndex(name, type, path) VALUES ('Iterators', 'Guide', 'feature
INSERT INTO searchIndex(name, type, path) VALUES ('JSON Merge Patch', 'Guide', 'features/merge_patch/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON Patch and Diff', 'Guide', 'features/json_patch/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('JSON Pointer', 'Guide', 'features/json_pointer/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Zero-copy JSON views', 'Guide', 'features/json_view/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('nlohmann Namespace', 'Guide', 'features/namespace/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Types', 'Guide', 'features/types/index.html');
INSERT INTO searchIndex(name, type, path) VALUES ('Types: Number Handling', 'Guide', 'features/types/number_handling/index.html');
-4
View File
@@ -60,10 +60,6 @@ itself is empty which is `#!cpp false` in the case of a string.
--8<-- "examples/empty.output"
```
## See also
- [basic_json_view::empty](../basic_json_view/empty.md) - the same check on a zero-copy view
## Version history
- Added in version 1.0.0.
@@ -34,10 +34,6 @@ Constant.
--8<-- "examples/is_array.output"
```
## See also
- [basic_json_view::is_array](../basic_json_view/is_array.md) - the same check on a zero-copy view
## Version history
- Added in version 1.0.0.
@@ -34,10 +34,6 @@ Constant.
--8<-- "examples/is_binary.output"
```
## See also
- [basic_json_view::is_binary](../basic_json_view/is_binary.md) - the same check on a zero-copy view
## Version history
- Added in version 3.8.0.
@@ -34,10 +34,6 @@ Constant.
--8<-- "examples/is_boolean.output"
```
## See also
- [basic_json_view::is_boolean](../basic_json_view/is_boolean.md) - the same check on a zero-copy view
## Version history
- Added in version 1.0.0.
@@ -69,11 +69,6 @@ with `allow_exceptions` set to `#!cpp false`: a parse error then yields a discar
--8<-- "examples/is_discarded.output"
```
## See also
- [basic_json_view::is_discarded](../basic_json_view/is_discarded.md) - the corresponding check on a zero-copy view,
which is `#!cpp true` if the view refers to no value
## Version history
- Added in version 1.0.0.
@@ -34,10 +34,6 @@ Constant.
--8<-- "examples/is_null.output"
```
## See also
- [basic_json_view::is_null](../basic_json_view/is_null.md) - the same check on a zero-copy view
## Version history
- Added in version 1.0.0.
@@ -49,7 +49,6 @@ constexpr bool is_number() const noexcept
- [is_number_integer()](is_number_integer.md) check if the value is an integer or unsigned integer number
- [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
- [is_number_float()](is_number_float.md) check if the value is a floating-point number
- [basic_json_view::is_number](../basic_json_view/is_number.md) - the same check on a zero-copy view
## Version history
@@ -40,7 +40,6 @@ Constant.
- [is_number()](is_number.md) check if the value is a number
- [is_number_integer()](is_number_integer.md) check if the value is an integer or unsigned integer number
- [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
- [basic_json_view::is_number_float](../basic_json_view/is_number_float.md) - the same check on a zero-copy view
## Version history
@@ -40,7 +40,6 @@ Constant.
- [is_number()](is_number.md) check if the value is a number
- [is_number_unsigned()](is_number_unsigned.md) check if the value is an unsigned integer number
- [is_number_float()](is_number_float.md) check if the value is a floating-point number
- [basic_json_view::is_number_integer](../basic_json_view/is_number_integer.md) - the same check on a zero-copy view
## Version history
@@ -40,7 +40,6 @@ Constant.
- [is_number()](is_number.md) check if the value is a number
- [is_number_integer()](is_number_integer.md) check if the value is an integer or unsigned integer number
- [is_number_float()](is_number_float.md) check if the value is a floating-point number
- [basic_json_view::is_number_unsigned](../basic_json_view/is_number_unsigned.md) - the same check on a zero-copy view
## Version history
@@ -34,10 +34,6 @@ Constant.
--8<-- "examples/is_object.output"
```
## See also
- [basic_json_view::is_object](../basic_json_view/is_object.md) - the same check on a zero-copy view
## Version history
- Added in version 1.0.0.
@@ -62,7 +62,6 @@ This library extends primitive types to binary types, because binary types are r
- [is_boolean()](is_boolean.md) returns whether the JSON value is a boolean
- [is_number()](is_number.md) returns whether the JSON value is a number
- [is_binary()](is_binary.md) returns whether the JSON value is a binary array
- [basic_json_view::is_primitive](../basic_json_view/is_primitive.md) - the same check on a zero-copy view
## Version history
@@ -34,10 +34,6 @@ Constant.
--8<-- "examples/is_string.output"
```
## See also
- [basic_json_view::is_string](../basic_json_view/is_string.md) - the same check on a zero-copy view
## Version history
- Added in version 1.0.0.
@@ -57,7 +57,6 @@ Note that though strings are containers in C++, they are treated as primitive va
- [is_primitive()](is_primitive.md) returns whether JSON value is primitive
- [is_array()](is_array.md) returns whether the value is an array
- [is_object()](is_object.md) returns whether the value is an object
- [basic_json_view::is_structured](../basic_json_view/is_structured.md) - the same check on a zero-copy view
## Version history
-4
View File
@@ -51,10 +51,6 @@ JSON value which is `1` in the case of a string.
--8<-- "examples/size.output"
```
## See also
- [basic_json_view::size](../basic_json_view/size.md) - the same function on a zero-copy view
## Version history
- Added in version 1.0.0.
-4
View File
@@ -47,10 +47,6 @@ Constant.
--8<-- "examples/type.output"
```
## See also
- [basic_json_view::type](../basic_json_view/type.md) - the same function on a zero-copy view
## Version history
- Added in version 1.0.0.
@@ -1,67 +0,0 @@
# <small>nlohmann::basic_json_document::</small>accept
```cpp
template<typename InputType>
static bool accept(InputType&& input,
const bool ignore_comments = false,
const bool ignore_trailing_commas = false);
```
Checks whether the input is valid JSON, accepting and rejecting exactly what
[`BasicJsonType::accept()`](../basic_json/accept.md) does, with the same options. Unlike [`parse()`](parse.md), this
function never throws an exception for invalid input, and the returned `#!cpp bool` is the only result -- no document
is returned.
## Template parameters
`InputType`
: A compatible input; see [`parse`](parse.md#template-parameters).
## Parameters
`input` (in)
: Input to check.
`ignore_comments` (in)
: whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
(`#!cpp false`); (optional, `#!cpp false` by default)
`ignore_trailing_commas` (in)
: whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or
yield a parse error (`#!cpp false`); (optional, `#!cpp false` by default)
## Return value
Whether the input is valid JSON.
## Exception safety
Strong guarantee: this function itself never throws for an invalid input; it can only throw what allocating the
input's own copy (for inputs that are always read into a buffer) throws.
## Complexity
Linear in the length of the input.
## Examples
??? example
```cpp
--8<-- "examples/basic_json_document__accept.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__accept.output"
```
## See also
- [parse](parse.md) - deserialize from a compatible input
- [`BasicJsonType::accept`](../basic_json/accept.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,58 +0,0 @@
# <small>nlohmann::basic_json_document::</small>basic_json_document
```cpp
// (1)
basic_json_document() = default;
// (2)
basic_json_document(basic_json_document&& other) noexcept = default;
// (3)
basic_json_document(const basic_json_document&) = delete;
```
1. Creates an empty (discarded) document: [`root()`](root.md) returns a discarded view, and
[`is_discarded()`](is_discarded.md) is `#!cpp true`.
2. Move constructor. Takes over `other`'s index and, if owned, its text; `other` is left as an empty document. Views
taken from `other` before the move remain valid, because the index is heap-allocated independently of the
`basic_json_document` object.
3. `basic_json_document` is move-only. Copying is disabled because it would either duplicate a potentially large index
and text, or leave two documents claiming to borrow the same buffer.
## Parameters
`other` (in)
: another document to move the index and text from
## Exception safety
No-throw guarantee: the default and move constructors never throw exceptions.
## Complexity
Constant, for the default and move constructors.
## Examples
??? example
The example below shows the default constructor and demonstrates that `basic_json_document` is move-only.
```cpp
--8<-- "examples/basic_json_document__basic_json_document.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__basic_json_document.output"
```
## See also
- [parse](parse.md) - deserialize from a compatible input
- [is_discarded](is_discarded.md) - return whether the last parse failed
## Version history
- Added in version 3.13.0.
@@ -1,56 +0,0 @@
# <small>nlohmann::</small>basic_json_document
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
template<typename BasicJsonType>
class basic_json_document;
```
A parsed JSON text, held as a flat index of its values
([16 bytes per value](../../home/architecture.md#node-index-of-json-views)) instead of a tree of `BasicJsonType` values.
Strings and numbers stay in the source text; only strings that contain escapes are decoded, into one buffer owned by
the document. [`basic_json_view`](../basic_json_view/index.md) is a read-only handle to one value of a
`basic_json_document`; [`materialize()`](../basic_json_view/materialize.md) turns a subtree back into the
`BasicJsonType` value that [`BasicJsonType::parse()`](../basic_json/parse.md) would have produced for it.
A document may **borrow** the text it was parsed from (the caller's buffer must then outlive the document) or **own**
it (a copy, or an rvalue `#!cpp std::string` that was moved in); see [`owns_source`](owns_source.md). `basic_json_document`
is move-only: copying a document would either duplicate a potentially large index and text, or leave two documents
claiming to borrow the same buffer, so it is disabled.
## Template parameters
`BasicJsonType`
: a specialization of [`basic_json`](../basic_json/index.md), for instance [`json`](../json.md) or
[`ordered_json`](../ordered_json.md). Only 64-bit `number_integer_t`/`number_unsigned_t` types are supported; this
is checked with a `static_assert`.
## Specializations
- [**json_document**](../json_document.md) - documents of the default specialization [`json`](../json.md)
- [**ordered_json_document**](../ordered_json_document.md) - documents of [`ordered_json`](../ordered_json.md)
## Member types
- **view_type** - the type of view returned by [`root()`](root.md) (`#!cpp basic_json_view<BasicJsonType>`)
- **value_t** - the JSON type enumeration, see [`basic_json::value_t`](../basic_json/value_t.md)
## Member functions
- [(constructor)](basic_json_document.md)
- [**parse**](parse.md) (_static_) - deserialize from a compatible input, borrowing or owning it as appropriate
- [**parse_copy**](parse_copy.md) (_static_) - deserialize a copy of a compatible input
- [**accept**](accept.md) (_static_) - check whether the input is valid JSON
- [**read**](read.md) - (re-)parse into this document, reusing its memory
- [**root**](root.md) - the view of the root value
- [**is_discarded**](is_discarded.md) - return whether the last parse failed
- [**source**](source.md) - the parsed text
- [**owns_source**](owns_source.md) - return whether the document holds its own copy of the text
- [**node_count**](node_count.md) - the number of index entries (values plus object keys)
- [**memory_usage**](memory_usage.md) - the number of bytes held by the document
- [**shrink_to_fit**](shrink_to_fit.md) - release unused index capacity
## Version history
- Added in version 3.13.0.
@@ -1,49 +0,0 @@
# <small>nlohmann::basic_json_document::</small>is_discarded
```cpp
bool is_discarded() const noexcept;
```
Returns whether the document holds no value, either because it was default-constructed or because the last call to
[`parse()`](parse.md), [`parse_copy()`](parse_copy.md), or [`read()`](read.md) failed with `allow_exceptions` set to
`#!cpp false`.
## Return value
`#!cpp true` if the document is discarded, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
When the document is discarded, [`root()`](root.md) returns a discarded view (its
[`is_discarded()`](../basic_json_view/is_discarded.md) is also `#!cpp true`).
## Examples
??? example
```cpp
--8<-- "examples/basic_json_document__is_discarded.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__is_discarded.output"
```
## See also
- [parse](parse.md) - deserialize from a compatible input
- [is_discarded (basic_json_view)](../basic_json_view/is_discarded.md) - return whether a view is invalid
## Version history
- Added in version 3.13.0.
@@ -1,50 +0,0 @@
# <small>nlohmann::basic_json_document::</small>memory_usage
```cpp
std::size_t memory_usage() const noexcept;
```
Returns the number of bytes held by the document: the node index, the decoded-string buffer (for strings that
contain escapes), and, for an owned document, its copy of the source text.
## Return value
The number of bytes the document holds, `0` for a [discarded](is_discarded.md) document.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
The exact value depends on the platform, the allocator, and the library's own layout, and may change between
versions; do not rely on it being a specific number, and do not compare it across different builds or platforms.
Compare it for the same document over time, or between documents built with the same binary, instead -- for instance
to observe the effect of [`shrink_to_fit()`](shrink_to_fit.md).
## Examples
??? example
```cpp
--8<-- "examples/basic_json_document__memory_usage.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__memory_usage.output"
```
## See also
- [node_count](node_count.md) - the number of index entries
- [shrink_to_fit](shrink_to_fit.md) - release unused index capacity
## Version history
- Added in version 3.13.0.
@@ -1,49 +0,0 @@
# <small>nlohmann::basic_json_document::</small>node_count
```cpp
std::size_t node_count() const noexcept;
```
Returns the number of entries in the document's flat index.
## Return value
The number of index entries: one per value (of any type, at any nesting depth) plus one per object key. `0` for a
[discarded](is_discarded.md) document.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
Each index entry is [16 bytes](../../home/architecture.md#node-index-of-json-views), so `#!cpp node_count() * 16` is
the size of the index itself (part, but not all, of [`memory_usage()`](memory_usage.md), which also counts decoded
strings and, for an owned document, the text).
## Examples
??? example
```cpp
--8<-- "examples/basic_json_document__node_count.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__node_count.output"
```
## See also
- [memory_usage](memory_usage.md) - the number of bytes held by the document
- [shrink_to_fit](shrink_to_fit.md) - release unused index capacity
## Version history
- Added in version 3.13.0.
@@ -1,49 +0,0 @@
# <small>nlohmann::basic_json_document::</small>owns_source
```cpp
bool owns_source() const noexcept;
```
Returns whether the document holds its own copy of the parsed text, as opposed to borrowing the caller's buffer.
## Return value
`#!cpp true` if the document owns the text returned by [`source()`](source.md), `#!cpp false` if it borrows it (or if
the document is [discarded](is_discarded.md)).
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
See the ownership table on [`parse`](parse.md#notes) for which inputs are borrowed and which are owned. A borrowed
document (`#!cpp owns_source() == false`) is only valid while the buffer it was parsed from is still alive.
## Examples
??? example
```cpp
--8<-- "examples/basic_json_document__owns_source.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__owns_source.output"
```
## See also
- [parse](parse.md) - deserialize from a compatible input
- [parse_copy](parse_copy.md) - deserialize a copy of a compatible input, always owned
- [source](source.md) - the parsed text
## Version history
- Added in version 3.13.0.
@@ -1,139 +0,0 @@
# <small>nlohmann::basic_json_document::</small>parse
```cpp
// (1)
template<typename InputType>
static basic_json_document parse(InputType&& input,
const bool allow_exceptions = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas = false);
// (2)
template<typename IteratorType>
static basic_json_document parse(IteratorType first, IteratorType last,
const bool allow_exceptions = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas = false);
```
1. Deserialize from a compatible input, borrowing or owning it depending on its value category and type (see Notes).
2. Deserialize from a pair of input iterators.
Both overloads accept exactly what [`BasicJsonType::parse()`](../basic_json/parse.md) accepts, with the same
`ignore_comments`/`ignore_trailing_commas` options, but build a [`basic_json_document`](index.md) (a flat index into
the input) instead of a tree of `BasicJsonType` values.
## Template parameters
`InputType`
: A compatible input, for instance:
- a `#!cpp std::string`, `#!cpp std::string_view`, or a C-style array of characters
- a pointer to a null-terminated string of single byte characters
- a container for which `#!cpp obj.data()` and `#!cpp obj.size()` give contiguous single-byte access, e.g.
`#!cpp std::vector<char>` or `#!cpp std::vector<std::uint8_t>`
- an `#!cpp std::istream` object, or anything else [`BasicJsonType::parse()`](../basic_json/parse.md) accepts
`IteratorType`
: a compatible iterator type, for instance a pair of pointers such as `ptr` and `ptr + len`, or a pair of
`#!cpp std::string::iterator`
## Parameters
`input` (in)
: Input to parse from.
`allow_exceptions` (in)
: whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
`ignore_comments` (in)
: whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
(`#!cpp false`); (optional, `#!cpp false` by default)
`ignore_trailing_commas` (in)
: whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or
yield a parse error (`#!cpp false`); (optional, `#!cpp false` by default)
`first` (in)
: iterator to the start of a character range
`last` (in)
: iterator to the end of a character range
## Return value
The parsed document. If `allow_exceptions` is `#!cpp false` and the input is not valid JSON, the returned document is
discarded; see [`is_discarded`](is_discarded.md).
## Exceptions
Throws the same exception [`BasicJsonType::parse()`](../basic_json/parse.md) throws for the same input and options --
the same exception id, message, and position -- because on a failing input the library's own parser is run on the
same bytes to produce the diagnostic. Additionally throws
[`out_of_range.416`](../../home/exceptions.md#jsonexceptionout_of_range416) if the input is 4 GiB or larger, a size
[`BasicJsonType::parse()`](../basic_json/parse.md) does not reject.
## Complexity
Linear in the length of the input.
## Notes
**Ownership.** Whether the document borrows `input` or owns a copy of it depends on its value category and type:
| `input` | ownership |
|--------------------------------------------------------------------------------------|--------------------------------------------------------------|
| lvalue byte container (`std::string`, `std::vector<char>`, ...), `std::string_view`, C string, character array | **borrowed** -- `input` must outlive the document |
| rvalue `#!cpp std::string` | **owned**, moved in without a copy |
| rvalue byte container other than `#!cpp std::string` | **owned**, copied |
| stream, wide string, or anything else read through the general input adapter | **owned**, read into a buffer (a stream is read to its end) |
For overload (2), a pair of pointers to single-byte integers (e.g. `#!cpp const char*`, `#!cpp std::uint8_t*`) is
borrowed. From C++20 on, so is any other contiguous iterator over single bytes, such as
`#!cpp std::vector<char>::iterator` or `#!cpp std::string::const_iterator`. Before C++20 these iterators cannot be
told apart from other class-type iterators, so their range is read into an owned buffer, as is any non-contiguous
range (e.g. of a `#!cpp std::list<char>`).
See [`owns_source`](owns_source.md) to check which happened after a call, and the
[feature page](../../features/json_view.md) for the reasoning.
**Numbers.** As for [`BasicJsonType::parse()`](../basic_json/parse.md), an integer literal too large for the 64-bit
integer type becomes a floating-point value.
## Examples
??? example "Example: (1) borrowed vs. owned input, and errors identical to `BasicJsonType::parse()`"
```cpp
--8<-- "examples/basic_json_document__parse.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__parse.output"
```
??? example "Example: (2) parse an iterator range (no NUL terminator required)"
```cpp
--8<-- "examples/basic_json_document__parse_iterator_pair.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__parse_iterator_pair.output"
```
## See also
- [parse_copy](parse_copy.md) - deserialize a copy of a compatible input
- [accept](accept.md) - check whether the input is valid JSON
- [read](read.md) - (re-)parse into this document, reusing its memory
- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
- [`BasicJsonType::parse`](../basic_json/parse.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,77 +0,0 @@
# <small>nlohmann::basic_json_document::</small>parse_copy
```cpp
template<typename InputType>
static basic_json_document parse_copy(InputType&& input,
const bool allow_exceptions = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas = false);
```
Deserialize from a compatible input, always taking the document's own copy of it, regardless of the value category or
type of `input`. Unlike [`parse()`](parse.md), the returned document never depends on `input` staying alive.
## Template parameters
`InputType`
: A compatible input; see [`parse`](parse.md#template-parameters).
## Parameters
`input` (in)
: Input to parse from.
`allow_exceptions` (in)
: whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
`ignore_comments` (in)
: whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
(`#!cpp false`); (optional, `#!cpp false` by default)
`ignore_trailing_commas` (in)
: whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or
yield a parse error (`#!cpp false`); (optional, `#!cpp false` by default)
## Return value
The parsed document, with [`owns_source()`](owns_source.md) `#!cpp true`. If `allow_exceptions` is `#!cpp false` and
the input is not valid JSON, the returned document is discarded; see [`is_discarded`](is_discarded.md).
## Exceptions
Same as [`parse`](parse.md#exceptions).
## Complexity
Linear in the length of the input.
## Notes
`parse_copy()` accepts and rejects exactly what [`parse()`](parse.md) does, and classifies numbers the same way; it
only differs in that the input is always copied rather than sometimes borrowed. Prefer [`parse()`](parse.md) when the
input's lifetime already covers the document's, since it avoids the copy for borrowed inputs.
## Examples
??? example
The example below returns a document from a function whose local buffer would otherwise not outlive it.
```cpp
--8<-- "examples/basic_json_document__parse_copy.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__parse_copy.output"
```
## See also
- [parse](parse.md) - deserialize from a compatible input, borrowing it where possible
- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
## Version history
- Added in version 3.13.0.
@@ -1,76 +0,0 @@
# <small>nlohmann::basic_json_document::</small>read
```cpp
template<typename InputType>
void read(InputType&& input,
const bool allow_exceptions = true,
const bool ignore_comments = false,
const bool ignore_trailing_commas = false);
```
(Re-)parses `input` into `#!cpp *this`, discarding the document's previous value and reusing its memory (the node
index, the decoded-string buffer, and, if applicable, the owned copy of the text) rather than allocating a fresh
document. [`parse()`](parse.md) is implemented in terms of this function, applied to a default-constructed document.
## Template parameters
`InputType`
: A compatible input; see [`parse`](parse.md#template-parameters).
## Parameters
`input` (in)
: Input to parse from.
`allow_exceptions` (in)
: whether to throw exceptions in case of a parse error (optional, `#!cpp true` by default)
`ignore_comments` (in)
: whether comments should be ignored and treated like whitespace (`#!cpp true`) or yield a parse error
(`#!cpp false`); (optional, `#!cpp false` by default)
`ignore_trailing_commas` (in)
: whether trailing commas in arrays or objects should be ignored and treated like whitespace (`#!cpp true`) or
yield a parse error (`#!cpp false`); (optional, `#!cpp false` by default)
## Exceptions
Same as [`parse`](parse.md#exceptions).
## Complexity
Linear in the length of the input.
## Notes
Every view taken from `#!cpp *this` before the call -- including the previous [`root()`](root.md) -- is invalidated,
whether or not the new parse succeeds; take fresh views from [`root()`](root.md) afterward.
`input` is borrowed or owned by the same rules as [`parse()`](parse.md#notes); a document can borrow on one call and
own on the next, since ownership is decided freshly each time.
## Examples
??? example
The example below parses a sequence of messages into the same document, reusing its memory instead of allocating
a new document for each one.
```cpp
--8<-- "examples/basic_json_document__read.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__read.output"
```
## See also
- [parse](parse.md) - deserialize from a compatible input
- [root](root.md) - the view of the root value
## Version history
- Added in version 3.13.0.
@@ -1,50 +0,0 @@
# <small>nlohmann::basic_json_document::</small>root
```cpp
view_type root() const noexcept;
```
Returns a view of the root value of the document.
## Return value
A [`view_type`](index.md#member-types) (i.e. `#!cpp basic_json_view<BasicJsonType>`) for the root value, or a
discarded view if the document is [discarded](is_discarded.md).
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
`root()` is a cheap handle into the document's index, not a copy of anything; call it as often as needed. The
returned view is valid under the same conditions as any other view of the document -- see
[Object inspection](../basic_json_view/index.md) -- in particular, it is invalidated by the next
[`read()`](read.md) or [`shrink_to_fit()`](shrink_to_fit.md) on this document.
## Examples
??? example
```cpp
--8<-- "examples/basic_json_document__root.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__root.output"
```
## See also
- [is_discarded](is_discarded.md) - return whether the last parse failed
- [materialize](../basic_json_view/materialize.md) - build the `BasicJsonType` value of a subtree
## Version history
- Added in version 3.13.0.
@@ -1,58 +0,0 @@
# <small>nlohmann::basic_json_document::</small>shrink_to_fit
```cpp
void shrink_to_fit();
```
Releases capacity that is no longer needed, both of the node index and of the buffer for decoded strings (strings that
contained escape sequences), e.g. after [`read()`](read.md) replaced a large document with a much smaller one. Like
`#!cpp std::vector::shrink_to_fit()`, this is a non-binding request: the library may keep more capacity than strictly
necessary.
## Exception safety
Strong guarantee: if an exception is thrown, there are no changes to the document.
## Exceptions
May throw `#!cpp std::bad_alloc` if the reallocation fails; on exception, the document is unchanged.
## Complexity
Linear in [`node_count()`](node_count.md) plus the length of the decoded strings.
## Notes
!!! warning "Invalidates views"
Unlike moving the document, `shrink_to_fit()` **invalidates every view taken from this document before the
call**, including a previously obtained [`root()`](root.md): the node index is moved into a new, smaller
allocation, and the old one is freed. Take a fresh view from [`root()`](root.md) after calling this function.
This is unlike `#!cpp std::vector::shrink_to_fit()`, which promises nothing about validity but in practice often
leaves iterators alone when it did not need to reallocate; here, an implementation that avoids a reallocation when
possible would be an internal optimization only, not a guarantee to rely on.
## Examples
??? example
```cpp
--8<-- "examples/basic_json_document__shrink_to_fit.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__shrink_to_fit.output"
```
## See also
- [node_count](node_count.md) - the number of index entries
- [memory_usage](memory_usage.md) - the number of bytes held by the document
- [root](root.md) - the view of the root value
## Version history
- Added in version 3.13.0.
@@ -1,48 +0,0 @@
# <small>nlohmann::basic_json_document::</small>source
```cpp
view_type::string_view_t source() const noexcept;
```
Returns the parsed text, whether it is borrowed from the caller or owned by the document.
## Return value
A `#!cpp string_view_t` (`#!cpp std::string_view` on C++17 and newer) over the parsed text, or an empty one if the
document is [discarded](is_discarded.md).
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
For a borrowed document, `source()` points directly into the caller's buffer, so it is only valid while that buffer
is; see [`owns_source`](owns_source.md).
## Examples
??? example
```cpp
--8<-- "examples/basic_json_document__source.cpp"
```
Output:
```json
--8<-- "examples/basic_json_document__source.output"
```
## See also
- [owns_source](owns_source.md) - return whether the document holds its own copy of the text
- [source_offset](../basic_json_view/source_offset.md) - byte offset of a value in the source text
## Version history
- Added in version 3.13.0.
@@ -1,51 +0,0 @@
# <small>nlohmann::basic_json_view::</small>basic_json_view
```cpp
basic_json_view() noexcept = default;
```
Creates an invalid (discarded) view: [`type()`](type.md) is `#!cpp value_t::discarded`,
[`is_discarded()`](is_discarded.md) is `#!cpp true`, and `#!cpp explicit operator bool()` is `#!cpp false`.
This is the only constructor a caller can use directly. Every other view is obtained from a
[`basic_json_document`](../basic_json_document/index.md), via [`root()`](../basic_json_document/root.md) or (once
element access is added) from navigating into a container.
## Exception safety
No-throw guarantee: this constructor never throws exceptions.
## Complexity
Constant.
## Notes
`basic_json_view` is trivially copyable (it holds two pointers), so a default-constructed view can be used as a
placeholder for "no value yet" and later be assigned a real view.
## Examples
??? example
The example below shows the default constructor and that a `basic_json_view` is a small, copyable handle.
```cpp
--8<-- "examples/basic_json_view__basic_json_view.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__basic_json_view.output"
```
## See also
- [is_discarded](is_discarded.md) - return whether the view is invalid
- [operator bool](operator_bool.md) - return whether the view refers to a value
- [root](../basic_json_document/root.md) - the view of a document's root value
## Version history
- Added in version 3.13.0.
@@ -1,61 +0,0 @@
# <small>nlohmann::basic_json_view::</small>empty
```cpp
bool empty() const noexcept;
```
Checks whether [`size()`](size.md) is `0`, as [`BasicJsonType::empty()`](../basic_json/empty.md) would for the same
value.
## Return value
The return value depends on the type and is defined as follows:
| Value type | return value |
|----------------------|-----------------|
| null | `#!cpp true` |
| discarded | `#!cpp true` |
| boolean | `#!cpp false` |
| string | `#!cpp false` |
| number | `#!cpp false` |
| object | `#!cpp object_t::empty()` |
| array | `#!cpp array_t::empty()` |
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
As for [`BasicJsonType::empty()`](../basic_json/empty.md), this does not return whether a string value is empty -- it
is `#!cpp false` for any string, regardless of its length.
## Examples
??? example
The example below uses [`size()`](size.md) and `empty()` to decide whether a parsed message is worth acting on,
without materializing it into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__size_empty.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__size_empty.output"
```
## See also
- [size](size.md) - return the number of elements
- [`BasicJsonType::empty`](../basic_json/empty.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,82 +0,0 @@
# <small>nlohmann::</small>basic_json_view
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
template<typename BasicJsonType>
class basic_json_view;
```
A read-only handle to one value of a [`basic_json_document`](../basic_json_document/index.md): two pointers (a pointer
to the document and a pointer into its index), trivially copyable. A view is valid as long as
- the document is alive,
- the document has not been re-parsed with [`read()`](../basic_json_document/read.md) (or
[`parse()`](../basic_json_document/parse.md) into it) or shrunk with
[`shrink_to_fit()`](../basic_json_document/shrink_to_fit.md) since the view was taken, and
- if the document borrows its source text, that text is still alive.
Moving the document itself does not invalidate its views: the index is heap-allocated independently of the
`basic_json_document` object.
`basic_json_view` provides the read-only part of the `BasicJsonType` interface: the type-inspection functions, and
[`materialize()`](materialize.md) to build the `BasicJsonType` value of a subtree on demand. It does not (yet) provide
element access, iteration, `get<T>()`, JSON Pointer support, `dump()`, or comparison.
## Template parameters
`BasicJsonType`
: a specialization of [`basic_json`](../basic_json/index.md), matching the
[`basic_json_document`](../basic_json_document/index.md) the view was taken from.
## Specializations
- [**json_view**](../json_view.md) - views of a [`json_document`](../json_document.md)
- [**ordered_json_view**](../ordered_json_view.md) - views of an [`ordered_json_document`](../ordered_json_document.md)
## Member types
- **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`
- **size_type** - `#!cpp std::size_t`
- **string_view_t** - `#!cpp std::string_view` on C++17 and newer, a minimal internal substitute otherwise
## Member functions
- [(constructor)](basic_json_view.md)
### Object inspection
- [**type**](type.md) - return the type of the value
- [**is_null**](is_null.md) - return whether the value is null
- [**is_boolean**](is_boolean.md) - return whether the value is a boolean
- [**is_number**](is_number.md) - return whether the value is a number
- [**is_number_integer**](is_number_integer.md) - return whether the value is an integer number
- [**is_number_unsigned**](is_number_unsigned.md) - return whether the value is an unsigned integer number
- [**is_number_float**](is_number_float.md) - return whether the value is a floating-point number
- [**is_string**](is_string.md) - return whether the value is a string
- [**is_array**](is_array.md) - return whether the value is an array
- [**is_object**](is_object.md) - return whether the value is an object
- [**is_binary**](is_binary.md) - return whether the value is a binary array (always `#!cpp false`)
- [**is_primitive**](is_primitive.md) - return whether the type is primitive
- [**is_structured**](is_structured.md) - return whether the type is structured
- [**is_discarded**](is_discarded.md) - return whether the view is invalid
- [**operator bool**](operator_bool.md) - return whether the view refers to a value
### Capacity
- [**size**](size.md) - return the number of elements
- [**empty**](empty.md) - return whether the value has no elements
### Conversion
- [**materialize**](materialize.md) - build the `BasicJsonType` value of this subtree
### Source access
- [**source_offset**](source_offset.md) - byte offset of this value in the document's source text
## Version history
- Added in version 3.13.0.
@@ -1,46 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_array
```cpp
bool is_array() const noexcept;
```
This function returns `#!cpp true` if and only if the value is an array.
## Return value
`#!cpp true` if the type is an array, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_structured](is_structured.md) - return whether the type is structured
- [size](size.md), [empty](empty.md) - the number of elements, and whether there are none
- [`BasicJsonType::is_array`](../basic_json/is_array.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,46 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_binary
```cpp
bool is_binary() const noexcept;
```
This function always returns `#!cpp false`: a JSON text has no binary values, so a view can never refer to one. The
function exists for interface parity with [`BasicJsonType::is_binary`](../basic_json/is_binary.md).
## Return value
`#!cpp false`, always.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [type](type.md) - return the type of the value
- [`BasicJsonType::is_binary`](../basic_json/is_binary.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,45 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_boolean
```cpp
bool is_boolean() const noexcept;
```
This function returns `#!cpp true` if and only if the value is a boolean.
## Return value
`#!cpp true` if the type is a boolean, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [type](type.md) - return the type of the value
- [`BasicJsonType::is_boolean`](../basic_json/is_boolean.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,55 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_discarded
```cpp
bool is_discarded() const noexcept;
```
Returns whether this view is invalid, i.e. does not refer to a value. This is the case for a default-constructed
view (see [(constructor)](basic_json_view.md)), and for [`root()`](../basic_json_document/root.md) of a document
that is itself [discarded](../basic_json_document/is_discarded.md) -- in particular, the root of a failed
[`parse()`](../basic_json_document/parse.md) with `allow_exceptions` set to `#!cpp false`.
## Return value
`#!cpp true` if the view is discarded, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
`#!cpp v.is_discarded()` and `#!cpp !static_cast<bool>(v)` are equivalent; use whichever reads better at the call
site.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [operator bool](operator_bool.md) - return whether the view refers to a value
- [(constructor)](basic_json_view.md) - the default constructor creates a discarded view
- [is_discarded (basic_json_document)](../basic_json_document/is_discarded.md) - return whether the last parse failed
- [`BasicJsonType::is_discarded`](../basic_json/is_discarded.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,45 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_null
```cpp
bool is_null() const noexcept;
```
This function returns `#!cpp true` if and only if the value is `#!json null`.
## Return value
`#!cpp true` if the type is `#!json null`, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [type](type.md) - return the type of the value
- [`BasicJsonType::is_null`](../basic_json/is_null.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,47 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_number
```cpp
bool is_number() const noexcept;
```
This function returns `#!cpp true` if and only if the value is a number, i.e. an integer, unsigned integer, or floating-point value. It is defined as `#!cpp is_number_integer() || is_number_float()`.
## Return value
`#!cpp true` if the type is a number, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_number_integer](is_number_integer.md) - return whether the value is an integer or unsigned integer number
- [is_number_unsigned](is_number_unsigned.md) - return whether the value is an unsigned integer number
- [is_number_float](is_number_float.md) - return whether the value is a floating-point number
- [`BasicJsonType::is_number`](../basic_json/is_number.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,51 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_number_float
```cpp
bool is_number_float() const noexcept;
```
This function returns `#!cpp true` if and only if the value is a floating-point number.
## Return value
`#!cpp true` if the type is `#!cpp value_t::number_float`, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
As for [`BasicJsonType::parse`](../basic_json/parse.md), an integer literal that does not fit into the 64-bit
integer type is classified as a floating-point number, so `is_number_float()` can be `#!cpp true` even for an
integer-looking token in the source text.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_number](is_number.md) - return whether the value is a number
- [`BasicJsonType::is_number_float`](../basic_json/is_number_float.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,51 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_number_integer
```cpp
bool is_number_integer() const noexcept;
```
This function returns `#!cpp true` if and only if the value is an integer or unsigned integer number.
## Return value
`#!cpp true` if the type is `#!cpp value_t::number_integer` or `#!cpp value_t::number_unsigned`, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
As for [`BasicJsonType::is_number_integer`](../basic_json/is_number_integer.md), this includes unsigned integer
values; use [`is_number_unsigned`](is_number_unsigned.md) to test for those specifically.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_number](is_number.md) - return whether the value is a number
- [is_number_unsigned](is_number_unsigned.md) - return whether the value is an unsigned integer number
- [`BasicJsonType::is_number_integer`](../basic_json/is_number_integer.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,45 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_number_unsigned
```cpp
bool is_number_unsigned() const noexcept;
```
This function returns `#!cpp true` if and only if the value is an unsigned integer number.
## Return value
`#!cpp true` if the type is `#!cpp value_t::number_unsigned`, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_number_integer](is_number_integer.md) - return whether the value is an integer or unsigned integer number
- [`BasicJsonType::is_number_unsigned`](../basic_json/is_number_unsigned.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,46 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_object
```cpp
bool is_object() const noexcept;
```
This function returns `#!cpp true` if and only if the value is an object.
## Return value
`#!cpp true` if the type is an object, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_structured](is_structured.md) - return whether the type is structured
- [size](size.md), [empty](empty.md) - the number of elements, and whether there are none
- [`BasicJsonType::is_object`](../basic_json/is_object.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,46 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_primitive
```cpp
bool is_primitive() const noexcept;
```
This function returns `#!cpp true` if and only if the value is primitive, i.e. `#!json null`, a boolean, a number, or a string. It is defined as `#!cpp is_null() || is_string() || is_boolean() || is_number()`.
## Return value
`#!cpp true` if the type is primitive, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_structured](is_structured.md) - return whether the type is structured (the complement of this function, for a
non-discarded view)
- [`BasicJsonType::is_primitive`](../basic_json/is_primitive.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,45 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_string
```cpp
bool is_string() const noexcept;
```
This function returns `#!cpp true` if and only if the value is a string.
## Return value
`#!cpp true` if the type is a string, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [source_offset](source_offset.md) - byte offset of this value in the document's source text
- [`BasicJsonType::is_string`](../basic_json/is_string.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,46 +0,0 @@
# <small>nlohmann::basic_json_view::</small>is_structured
```cpp
bool is_structured() const noexcept;
```
This function returns `#!cpp true` if and only if the value is structured, i.e. an array or an object. It is defined as `#!cpp is_array() || is_object()`.
## Return value
`#!cpp true` if the type is structured, `#!cpp false` otherwise.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_primitive](is_primitive.md) - return whether the type is primitive
- [size](size.md), [empty](empty.md) - the number of elements, and whether there are none
- [`BasicJsonType::is_structured`](../basic_json/is_structured.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,69 +0,0 @@
# <small>nlohmann::basic_json_view::</small>materialize
```cpp
BasicJsonType materialize() const;
```
Builds the `BasicJsonType` value of this subtree: the value [`BasicJsonType::parse()`](../basic_json/parse.md) would
have produced for the same source text, allocated for the first time by this call.
## Return value
The `BasicJsonType` value of this subtree, or a discarded `BasicJsonType` value (`#!cpp BasicJsonType(value_t::discarded)`)
if the view is [discarded](is_discarded.md).
## Exception safety
Strong guarantee: if an exception is thrown, there are no changes to the view or the document it refers to (nothing
about either is mutated by this function).
## Exceptions
May throw `#!cpp std::bad_alloc` (via `BasicJsonType`'s allocator) if constructing the result fails.
## Complexity
Linear in the size of the subtree.
## Notes
`materialize()` replays the subtree through the same SAX builder [`BasicJsonType::parse()`](../basic_json/parse.md)
uses internally, so the result matches it exactly -- including, for an object, that a repeated key keeps only its
last value. The replay is iterative, so it is not limited by the call stack the way a naive recursive conversion
would be; the JSON nesting depth is limited only by available memory, as for `BasicJsonType::parse()` itself.
Unlike parsing with [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) enabled, the values
produced by `materialize()` do not carry source positions: there is no lexer run during the replay to record them.
Calling `materialize()` on the same view repeatedly builds a new, independent `BasicJsonType` value each time; it
never caches the result.
## Examples
??? example
The example below skips messages that are not useful -- a discarded value, or an empty array -- using only
[`is_array()`](is_array.md) and [`empty()`](empty.md), and calls `materialize()` only for the messages that are
actually used, so no `BasicJsonType` value (and none of its per-element allocations) is ever built for the
skipped ones.
```cpp
--8<-- "examples/basic_json_view__materialize.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__materialize.output"
```
## See also
- [root](../basic_json_document/root.md) - the view of a document's root value
- [`BasicJsonType::parse`](../basic_json/parse.md) - build a `BasicJsonType` value directly from a JSON text
- [`JSON_DIAGNOSTIC_POSITIONS`](../macros/json_diagnostic_positions.md) - source positions on parsed values (not
produced by `materialize()`)
## Version history
- Added in version 3.13.0.
@@ -1,46 +0,0 @@
# <small>nlohmann::basic_json_view::</small>operator bool
```cpp
explicit operator bool() const noexcept;
```
Returns whether this view refers to a value, i.e. the negation of [`is_discarded()`](is_discarded.md). Being
`#!cpp explicit`, this conversion is only considered in a boolean context (`#!cpp if (v)`, `#!cpp !v`, `#!cpp v &&
...`), not for implicit conversions to other types.
## Return value
`#!cpp true` if the view refers to a value, `#!cpp false` if it is [discarded](is_discarded.md).
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_discarded](is_discarded.md) - return whether the view is invalid
## Version history
- Added in version 3.13.0.
@@ -1,60 +0,0 @@
# <small>nlohmann::basic_json_view::</small>size
```cpp
size_type size() const noexcept;
```
Returns the number of elements, as [`BasicJsonType::size()`](../basic_json/size.md) would for the same value.
## Return value
The return value depends on the type and is defined as follows:
| Value type | return value |
|----------------------|-----------------------------|
| null | `0` |
| discarded | `0` |
| boolean | `1` |
| string | `1` |
| number | `1` |
| object | number of key/value pairs |
| array | number of elements |
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant: for an object or array, the element count is stored in the index, not counted on demand.
## Notes
As for [`BasicJsonType::size()`](../basic_json/size.md), this does not return the length of a string value -- it is
`1` for a string, regardless of its length.
## Examples
??? example
The example below uses `size()` and [`empty()`](empty.md) to decide whether a parsed message is worth acting on,
without materializing it into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__size_empty.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__size_empty.output"
```
## See also
- [empty](empty.md) - return whether the value has no elements
- [`BasicJsonType::size`](../basic_json/size.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
@@ -1,55 +0,0 @@
# <small>nlohmann::basic_json_view::</small>source_offset
```cpp
std::size_t source_offset() const noexcept;
```
Returns the byte offset of this value in the document's [`source()`](../basic_json_document/source.md) text, without
materializing anything.
## Return value
- For a string with no escapes, a number, `#!json true`/`#!json false`/`#!json null`, an array, or an object: the
byte offset of the first byte of the value's token (for a string: the first byte after the opening quote) in
[`source()`](../basic_json_document/source.md).
- `#!cpp static_cast<std::size_t>(-1)` for a [discarded](is_discarded.md) view, and for a string that contains
escapes -- such a string was decoded once into the document's own buffer, so there is no single byte range in
`source()` left to point at.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
This is a raw offset, not a length: the API does not (yet) expose how many bytes the token occupies in the source
text, so `source_offset()` alone is enough to report *where* a value came from (for an error message, for syntax
highlighting, ...) but not to slice its exact text back out of [`source()`](../basic_json_document/source.md) for a
string, whose token length is not the same as its decoded [`size()`](size.md).
## Examples
??? example
```cpp
--8<-- "examples/basic_json_view__source_offset.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__source_offset.output"
```
## See also
- [source](../basic_json_document/source.md) - the parsed text
- [is_string](is_string.md) - return whether the value is a string
## Version history
- Added in version 3.13.0.
@@ -1,53 +0,0 @@
# <small>nlohmann::basic_json_view::</small>type
```cpp
value_t type() const noexcept;
```
Returns the type of the value this view refers to, as a value from the [`value_t`](../basic_json/value_t.md)
enumeration -- the same enumeration [`BasicJsonType::type()`](../basic_json/type.md) uses.
## Return value
The type of the value; `#!cpp value_t::discarded` for a [discarded](is_discarded.md) view.
## Exception safety
No-throw guarantee: this function never throws exceptions.
## Complexity
Constant.
## Notes
Unlike [`BasicJsonType::type()`](../basic_json/type.md), this function can never return `#!cpp value_t::binary`: a
JSON text has no binary values, so `type()` only distinguishes the eight ordinary JSON value types (plus
`#!cpp discarded`).
## Examples
??? example
The example below classifies several parsed documents by the type of their root value, without materializing any
of them into a `BasicJsonType` value.
```cpp
--8<-- "examples/basic_json_view__type_predicates.cpp"
```
Output:
```json
--8<-- "examples/basic_json_view__type_predicates.output"
```
## See also
- [is_null](is_null.md), [is_boolean](is_boolean.md), [is_number](is_number.md), [is_string](is_string.md),
[is_array](is_array.md), [is_object](is_object.md) - type-specific predicates built on `type()`
- [`BasicJsonType::type`](../basic_json/type.md) - the corresponding function of `basic_json`
## Version history
- Added in version 3.13.0.
-35
View File
@@ -1,35 +0,0 @@
# <small>nlohmann::</small>json_document
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using json_document = basic_json_document<json>;
```
This type is a [`basic_json_document`](basic_json_document/index.md) of the default [`json`](json.md)
specialization.
## Examples
??? example
The example below demonstrates how to use the type `nlohmann::json_document`.
```cpp
--8<-- "examples/json_document.cpp"
```
Output:
```json
--8<-- "examples/json_document.output"
```
## See also
- [json_view](json_view.md) - a view of a value of a `json_document`
- [ordered_json_document](ordered_json_document.md) - the corresponding document for `ordered_json`
## Version history
Since version 3.13.0.
-34
View File
@@ -1,34 +0,0 @@
# <small>nlohmann::</small>json_view
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using json_view = basic_json_view<json>;
```
This type is a [`basic_json_view`](basic_json_view/index.md) of a value of a [`json_document`](json_document.md).
## Examples
??? example
The example below demonstrates how to use the type `nlohmann::json_view`.
```cpp
--8<-- "examples/json_view.cpp"
```
Output:
```json
--8<-- "examples/json_view.output"
```
## See also
- [json_document](json_document.md) - the document type this view refers into
- [ordered_json_view](ordered_json_view.md) - the corresponding view for `ordered_json_document`
## Version history
Since version 3.13.0.
@@ -1,38 +0,0 @@
# <small>nlohmann::</small>ordered_json_document
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using ordered_json_document = basic_json_document<ordered_json>;
```
This type is a [`basic_json_document`](basic_json_document/index.md) of the [`ordered_json`](ordered_json.md)
specialization: [`materialize()`](basic_json_view/materialize.md) on one of its views preserves the insertion order
of object keys, instead of sorting them like [`json_document`](json_document.md) does.
## Examples
??? example
The example below demonstrates how `ordered_json_document` preserves the insertion order of object keys when
materializing.
```cpp
--8<-- "examples/ordered_json_document.cpp"
```
Output:
```json
--8<-- "examples/ordered_json_document.output"
```
## See also
- [ordered_json_view](ordered_json_view.md) - a view of a value of an `ordered_json_document`
- [json_document](json_document.md) - the corresponding document for the default `json` specialization
- [Object Order](../features/object_order.md)
## Version history
Since version 3.13.0.
-35
View File
@@ -1,35 +0,0 @@
# <small>nlohmann::</small>ordered_json_view
<small>Defined in header `<nlohmann/json_view.hpp>`</small>
```cpp
using ordered_json_view = basic_json_view<ordered_json>;
```
This type is a [`basic_json_view`](basic_json_view/index.md) of a value of an
[`ordered_json_document`](ordered_json_document.md).
## Examples
??? example
The example below demonstrates how to use the type `nlohmann::ordered_json_view`.
```cpp
--8<-- "examples/ordered_json_view.cpp"
```
Output:
```json
--8<-- "examples/ordered_json_view.output"
```
## See also
- [ordered_json_document](ordered_json_document.md) - the document type this view refers into
- [json_view](json_view.md) - the corresponding view for `json_document`
## Version history
Since version 3.13.0.
@@ -1,19 +0,0 @@
#include <iostream>
#include <nlohmann/json.hpp>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// accept() behaves exactly like basic_json::accept(): the same inputs are
// accepted or rejected, with the same ignore_comments/ignore_trailing_commas
// options
std::cout << json_document::accept(R"({"a": 1})") << '\n';
std::cout << json_document::accept(R"({"a": 1,})") << '\n'; // trailing comma: rejected by default
std::cout << json_document::accept(R"({"a": 1,})", false, true) << '\n'; // ignore_trailing_commas
std::cout << (json_document::accept(R"({"a": 1})") == nlohmann::json::accept(R"({"a": 1})")) << '\n';
}
@@ -1,4 +0,0 @@
true
false
true
true
@@ -1,23 +0,0 @@
#include <iostream>
#include <utility>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// the default constructor creates an empty (discarded) document
json_document empty;
std::cout << empty.is_discarded() << '\n';
// json_document is move-only: parse() itself returns by value (moved out),
// and a document can be moved again, e.g. into a container
json_document doc = json_document::parse(R"({"a": 1})");
json_document moved = std::move(doc);
std::cout << moved.root().is_object() << '\n';
// copying is disabled at compile time:
// json_document another = moved; // does not compile
}
@@ -1,2 +0,0 @@
true
true
@@ -1,19 +0,0 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// with allow_exceptions == false, a parse error produces a discarded
// document instead of throwing -- exactly like basic_json::parse()
json_document doc = json_document::parse(R"({"a": )", /* allow_exceptions */ false);
std::cout << doc.is_discarded() << '\n';
std::cout << doc.root().is_discarded() << '\n';
// a successful parse is never discarded
json_document ok = json_document::parse(R"({"a": 1})", false);
std::cout << ok.is_discarded() << '\n';
}
@@ -1,3 +0,0 @@
true
true
false
@@ -1,28 +0,0 @@
#include <iostream>
#include <string>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// long enough that copying it needs a real (heap) allocation, so the
// comparison below does not depend on the standard library's small
// string optimization threshold
const std::string text = std::string(200, ' ') + "[1, 2, 3, 4, 5]";
// memory_usage() is not portable across platforms/allocators/compilers, so
// compare it relatively instead of printing the raw byte count
json_document borrowed = json_document::parse(text);
json_document owned = json_document::parse_copy(text);
// the owned document additionally stores its own copy of the source text
std::cout << (owned.memory_usage() > borrowed.memory_usage()) << '\n';
// a document with more values needs a larger index
json_document small = json_document::parse(std::string("[1]"));
json_document large = json_document::parse(std::string("[1, 2, 3, 4, 5, 6, 7, 8, 9, 10]"));
std::cout << (large.memory_usage() > small.memory_usage()) << '\n';
}
@@ -1,2 +0,0 @@
true
true
@@ -1,15 +0,0 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
// node_count() is the size of the flat index: one 16-byte node per value,
// plus one per object key (values and keys are all the index stores)
json_document scalar = json_document::parse("42");
std::cout << scalar.node_count() << '\n';
json_document doc = json_document::parse(R"({"a": 1, "b": [1, 2]})");
std::cout << doc.node_count() << '\n';
}
@@ -1,2 +0,0 @@
1
7
@@ -1,24 +0,0 @@
#include <iostream>
#include <string>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
std::string text = R"({"a": 1})";
// borrowed: the document only points into `text`; `text` must outlive it
json_document borrowed = json_document::parse(text);
std::cout << borrowed.owns_source() << '\n';
// owned: parse_copy() always takes its own copy
json_document copied = json_document::parse_copy(text);
std::cout << copied.owns_source() << '\n';
// owned: an rvalue std::string is moved in, not copied, but still owned
json_document moved_in = json_document::parse(std::string(text));
std::cout << moved_in.owns_source() << '\n';
}
@@ -1,3 +0,0 @@
false
true
true
@@ -1,33 +0,0 @@
#include <iostream>
#include <string>
#include <nlohmann/json.hpp>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// an lvalue std::string is BORROWED: the document only stores a pointer
// into `text`, so `text` must outlive `borrowed`
std::string text = R"({"count": 3})";
json_document borrowed = json_document::parse(text);
std::cout << borrowed.owns_source() << '\n'; // false
// an rvalue std::string is MOVED into the document -- no copy of the text
json_document owned = json_document::parse(std::string(R"({"count": 3})"));
std::cout << owned.owns_source() << '\n'; // true
// errors are identical to basic_json::parse: same exception id, message,
// and position, because the library parser runs on the same bytes on a
// failing input
try
{
static_cast<void>(json_document::parse(R"({"count": )"));
}
catch (const nlohmann::json::parse_error& e)
{
std::cout << e.id << '\n';
}
}
@@ -1,3 +0,0 @@
false
true
101
@@ -1,22 +0,0 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
json_document parse_from_temporary_buffer()
{
char buffer[] = R"({"a": 1})";
// parse() would borrow `buffer`, which is about to go out of scope;
// parse_copy() takes its own copy instead, so the returned document does
// not depend on `buffer` afterward
return json_document::parse_copy(buffer);
}
int main()
{
std::cout << std::boolalpha;
json_document doc = parse_from_temporary_buffer();
std::cout << doc.owns_source() << '\n';
std::cout << doc.root().is_object() << '\n';
}
@@ -1,2 +0,0 @@
true
true
@@ -1,22 +0,0 @@
#include <iostream>
#include <vector>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// a JSON value embedded in a larger, non-null-terminated buffer (e.g. a
// slice received over the network)
std::vector<char> buffer = {'[', '1', ',', '2', ']', 'j', 'u', 'n', 'k'};
// a pointer pair is BORROWED, exactly like a byte container lvalue: the
// document points into the buffer. (From C++20 on, std::vector<char>
// iterators are borrowed as well; before, they are copied.)
const char* first = buffer.data();
json_document doc = json_document::parse(first, first + 5);
std::cout << doc.root().is_array() << ' ' << doc.root().size() << '\n';
std::cout << doc.owns_source() << '\n'; // false: borrowed
}
@@ -1,2 +0,0 @@
true 2
false
@@ -1,31 +0,0 @@
#include <iostream>
#include <string>
#include <vector>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
std::vector<std::string> messages =
{
R"({"id": 1})", R"({"id": 2, "tag": "x"})", R"({"id": 3})"
};
// parse into the same document over and over: its node index and decode
// buffer are reused instead of being freed and reallocated for each message
json_document doc;
std::size_t total = 0;
for (const auto& msg : messages)
{
doc.read(msg);
total += doc.root().size();
}
std::cout << total << '\n';
// read() can also change what kind of input is owned/borrowed between calls
doc.read(std::string(R"({"owned": true})"));
std::cout << doc.owns_source() << '\n';
}
@@ -1,2 +0,0 @@
4
true
@@ -1,19 +0,0 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
json_document doc = json_document::parse(R"({"greeting": "hi"})");
std::cout << doc.root().is_object() << '\n';
// root() is a cheap handle, not a copy: repeated calls observe the same value
std::cout << (doc.root().type() == doc.root().type()) << '\n';
// the root of a failed parse (allow_exceptions == false) is discarded
json_document failed = json_document::parse("{", false);
std::cout << failed.root().is_discarded() << '\n';
}
@@ -1,3 +0,0 @@
true
true
true
@@ -1,44 +0,0 @@
#include <iostream>
#include <sstream>
#include <string>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// build a large array (many nodes), then read a small one into the same
// document: the index grown for the large input is still allocated
std::ostringstream big;
big << '[';
for (int i = 0; i < 500; ++i)
{
if (i != 0)
{
big << ',';
}
big << i;
}
big << ']';
json_document doc;
doc.read(big.str());
const std::size_t big_nodes = doc.node_count();
doc.read(std::string("[1]"));
std::cout << (doc.node_count() < big_nodes) << '\n'; // far fewer live nodes now
const std::size_t before = doc.memory_usage();
// shrink_to_fit() moves the index into a block sized for what is actually
// used. This INVALIDATES every view taken from this document before the
// call (they point into the old, now-freed block) -- take fresh ones from
// root() afterward.
doc.shrink_to_fit();
const std::size_t after = doc.memory_usage();
std::cout << (after <= before) << '\n';
// a freshly taken view is valid and correct
std::cout << doc.root().is_array() << ' ' << doc.root().size() << '\n';
}
@@ -1,3 +0,0 @@
true
true
true 1
@@ -1,20 +0,0 @@
#include <iostream>
#include <string>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
std::string text = R"({"a": 1})";
json_document doc = json_document::parse(text);
// source() is the parsed text, whether borrowed or owned
std::cout << (doc.source().size() == text.size()) << '\n';
std::cout << std::string(doc.source().data(), doc.source().size()) << '\n';
// for a borrowed document, source() points right into the caller's buffer
std::cout << (doc.source().data() == text.data()) << '\n';
}
@@ -1,3 +0,0 @@
true
{"a": 1}
true
@@ -1,17 +0,0 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
int main()
{
std::cout << std::boolalpha;
// the default constructor is the only public one: it creates an invalid
// (discarded) view, useful as a "no value yet" placeholder
nlohmann::json_view v;
std::cout << static_cast<bool>(v) << ' ' << v.is_discarded() << '\n';
// views are trivially copyable handles (two pointers); the document owns
// the actual data
nlohmann::json_view copy = v;
std::cout << static_cast<bool>(copy) << '\n';
}
@@ -1,2 +0,0 @@
false true
false
@@ -1,33 +0,0 @@
#include <array>
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
// three incoming messages; skip the ones that are not useful without ever
// building a nlohmann::json value for them
json_document heartbeat = json_document::parse("null");
json_document empty_batch = json_document::parse("[]");
json_document batch = json_document::parse(R"([{"id": 1}, {"id": 2}, {"id": 3}])");
std::array<const json_document*, 3> messages = {{&heartbeat, &empty_batch, &batch}};
for (const json_document* d : messages)
{
// is_array()/empty() only look at the flat index: a discarded
// heartbeat or an empty batch is never turned into a nlohmann::json
// value, so no per-element allocation happens for them
if (!d->root().is_array() || d->root().empty())
{
std::cout << "skipped\n";
continue;
}
// materialize() replays the subtree through the same SAX builder
// basic_json::parse() uses, so the result is exactly what
// basic_json::parse() would have produced for the same text
nlohmann::json value = d->root().materialize();
std::cout << value.dump() << '\n';
}
}
@@ -1,3 +0,0 @@
skipped
skipped
[{"id":1},{"id":2},{"id":3}]
@@ -1,22 +0,0 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// decide whether a batch is worth processing before building any
// nlohmann::json value for it
json_document batch = json_document::parse(R"([1, 2, 3, 4, 5])");
json_document empty_batch = json_document::parse("[]");
std::cout << batch.root().empty() << ' ' << batch.root().size() << '\n';
std::cout << empty_batch.root().empty() << ' ' << empty_batch.root().size() << '\n';
// as for basic_json: null has size 0, every other scalar has size 1
json_document n = json_document::parse("null");
json_document s = json_document::parse(R"("hi")");
std::cout << n.root().size() << ' ' << s.root().size() << '\n';
}
@@ -1,3 +0,0 @@
false 5
true 0
0 1
@@ -1,33 +0,0 @@
#include <iostream>
#include <string>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// source_offset() points into source(): useful to report *where* in the
// original text a value came from (error messages, syntax highlighting,
// forwarding a sub-range verbatim, ...) without materializing it
json_document doc = json_document::parse(R"( 123)");
auto v = doc.root();
std::cout << v.source_offset() << ' '
<< std::string(doc.source().data() + v.source_offset(), 3) << '\n';
// a string without escapes also stays in the source text
json_document plain = json_document::parse(R"("ab")");
std::cout << plain.source()[plain.root().source_offset()] << '\n';
// a string with escapes is decoded once into the document's own buffer, so
// there is no single byte range in source() to point at: source_offset()
// returns the "not applicable" sentinel
json_document escaped = json_document::parse(R"("a\nb")");
std::cout << (escaped.root().source_offset() == static_cast<std::size_t>(-1)) << '\n';
// a discarded view -- default-constructed, or the root of a failed parse
// with allow_exceptions == false -- has no offset either
json_document failed = json_document::parse("not json", false);
std::cout << (failed.root().source_offset() == static_cast<std::size_t>(-1)) << '\n';
}
@@ -1,4 +0,0 @@
2 123
a
true
true
@@ -1,43 +0,0 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// several incoming messages, one json_document per message. type() and
// is_*() only look at the flat index built by parse(); no nlohmann::json
// tree exists yet, and none is built unless materialize() is called
json_document d_null = json_document::parse("null");
json_document d_bool = json_document::parse("true");
json_document d_int = json_document::parse("-42");
json_document d_unsigned = json_document::parse("42");
json_document d_float = json_document::parse("4.2");
json_document d_string = json_document::parse(R"("hi")");
json_document d_array = json_document::parse("[1, 2, 3]");
json_document d_object = json_document::parse(R"({"a": 1})");
std::cout << d_null.root().is_null() << '\n';
std::cout << d_bool.root().is_boolean() << '\n';
std::cout << d_int.root().is_number() << ' ' << d_int.root().is_number_integer() << '\n';
std::cout << d_unsigned.root().is_number_unsigned() << '\n';
std::cout << d_float.root().is_number_float() << '\n';
std::cout << d_string.root().is_string() << '\n';
std::cout << d_array.root().is_array() << ' ' << d_array.root().is_structured() << '\n';
std::cout << d_object.root().is_object() << ' ' << d_object.root().is_primitive() << '\n';
// JSON text can never produce a binary value: is_binary() is always false
std::cout << d_array.root().is_binary() << '\n';
// a default-constructed view, and the root of a document that failed to
// parse without exceptions, are both discarded
nlohmann::json_view invalid;
json_document failed = json_document::parse("not json", /* allow_exceptions */ false);
std::cout << static_cast<bool>(invalid) << ' ' << invalid.is_discarded() << '\n';
std::cout << static_cast<bool>(failed.root()) << ' ' << failed.root().is_discarded() << '\n';
// type() returns the same value_t enumeration as basic_json::type()
std::cout << (d_object.root().type() == nlohmann::json::value_t::object) << '\n';
}
@@ -1,12 +0,0 @@
true
true
true true
true
true
true
true true
true false
false
false true
false true
true
@@ -1,16 +0,0 @@
#include <iostream>
#include <nlohmann/json_view.hpp>
using json_document = nlohmann::json_document;
int main()
{
std::cout << std::boolalpha;
// json_document is basic_json_document<nlohmann::json>: same value types
// and containers as the ordinary json specialization
json_document doc = json_document::parse(R"({"pi": 3.14, "numbers": [1, 2, 3]})");
std::cout << doc.root().is_object() << '\n';
std::cout << doc.root().materialize().dump() << '\n';
}
@@ -1,2 +0,0 @@
true
{"numbers":[1,2,3],"pi":3.14}

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