Commit Graph
7 Commits
Author SHA1 Message Date
Niels Lohmann 4dcba03757 State the exact input size limit of json_document
The check rejects inputs of 0xFFFFFFF0 bytes or more, but the exception
message and the documentation said 4 GiB. Name the limit once
(max_input_size), and state 4 GiB minus 16 bytes in the message and the
documentation. Test the limit with a container that only claims the size.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-14 17:53:11 +02:00
Niels Lohmann 0f6c4dda11 Add json_document and json_view: node index, parser, and document
Add json_document and json_view, a read-only, zero-copy index of a
JSON text, as the first public slice of the zero-copy view (#5295).

A parse produces a flat array of 16-byte nodes in document order,
one per value and one per object key. Strings stay in the source
text; escaped strings are decoded into an arena. Integers are
converted while their digits are in the cache; floats keep only
their digit layout and are converted on read. Containers store the
size of their subtree, so a reader can step over one in constant
time. A document makes a handful of allocations, however many
values it has.

The parser accepts exactly what json::parse accepts, with every
combination of ignore_comments and ignore_trailing_commas, with and
without a trailing NUL, and under JSON_STRICT_NUL_HANDLING. It is
portable C++11 and does not depend on byte order.

basic_json_document adds parse, parse_copy, accept, read (reuses a
document's memory), root, is_discarded, source, owns_source,
node_count, memory_usage, and shrink_to_fit. basic_json_view adds
type, the is_* queries, operator bool, size, empty, materialize,
and source_offset. A parse error throws the same exception
basic_json::parse would throw for the same input, message and
position included.

detail::abi_config keeps JSON_STRICT_NUL_HANDLING and
JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON readable after json.hpp
undefines them, in the ABI namespace so they always match the
basic_json in use.

A NUL byte that ends a // comment is the end of the input, as in
parse() since #5696.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-14 17:53:03 +02:00
Niels Lohmann aa9620fb15 Skip the indentation after a newline 8 bytes at a time (#5810)
Pretty-printed JSON indents every line with a run of spaces, which
skip_whitespace() read one character at a time. For contiguous input
(bulk_scan) the lexer now skips the spaces after a newline 8 bytes at a
time directly in the input buffer, including the leading spaces of the
last, partial word. This bypasses get(), which is safe because
bulk_scan implies the lazy position from the previous commit: nothing
is counted per character.

Compared to lazy positions alone, pretty-printed input (twitter,
citm_catalog with indent 2 and 4) parses up to 13% faster and accept()
gets up to 30% faster (GCC 13 and clang 18 on x86-64, Apple clang 21 on
arm64). Minified input is unchanged within noise.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 17:16:52 +02:00
Niels Lohmann f23830b65e Derive the lexer position lazily for seekable input (#5809)
* Derive the lexer position lazily for seekable input

The lexer counted the read position on every character: two increments
and a newline check per get(), all on members kept in memory. For
seekable input (pointers, strings, other random-access byte ranges) the
position can be derived instead: chars_read_total is the adapter's read
count (including reads at EOF) minus a pending unget, and line and
column are recomputed from the consumed input only when get_position()
is called, i.e. on parse errors. JSON_DIAGNOSTIC_POSITIONS uses the new
O(1) get_chars_read_total(). Stream, file, wide-string and user-defined
adapters keep the eager counters.

Parsing pretty-printed input gets 8-12% faster and accept() 12-27%
(canada, citm_catalog, twitter; clang 21 arm64 and GCC 13 x86-64).
Error messages, byte offsets, SAX positions and diagnostic positions are
unchanged (differential comparison against develop on 548k inputs).

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

* Move the std::vector<std::byte> binary type tests out of unit-regression3

The #4804/#4209 tests instantiated a second basic_json specialization
(with_binary_t<std::vector<std::byte>>), including its parser and CBOR
reader. With clang 18, the C++20 object of unit-regression3.cpp had
32656 COFF sections on develop; the lazy position helpers pushed it to
32975, past what the MinGW linker of the Windows clang jobs handles
("relocation truncated to fit: IMAGE_REL_AMD64_REL32 against .rdata").
unit-custom-binary-type.cpp already instantiates the same type, so the
tests move there; unit-regression3.cpp drops to 27616 sections.

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

* Report the parse errors of the position test via SAX

The test caught json::parse_error, so it aborted in the
ci_test_noexceptions build, where JSON_NOEXCEPTION turns the throw into
std::abort(). sax_parse() hands the error position and the exception
object to parse_error() without throwing, so the test now records them
there and runs in every configuration.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-13 17:16:52 +02:00
Niels Lohmann 6197341a21 Clean up non-code files (#5801)
* Clean up README, contribution guide, and repository metadata

- REUSE.toml: fix the Hedley path and SPDX id (CC0-1.0), mark the docset
  icons as the public-domain JSON logo
- CITATION.cff: v3.12.0 was released on 2025-04-11
- FILES.md: list all workflows, describe the Meson option defaults
- README: ctest -LE, table of contents, typos, stale Android/MinGW advice,
  moved links, merge duplicate Thanks entries, list the analysis tools
  used in CI
- CONTRIBUTING: iterative parser, json_literals.hpp is generated, links
- .gitignore: backups and release outputs; .gitattributes: mark
  generated files
- labeler: label other build systems and .github documentation
- MODULE.bazel: add the module version

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

* Clean up CI, CMake, Makefile, and Bazel files

- CMakeLists.txt: avoid VERSION_GREATER_EQUAL, which CMake < 3.7 lacks
- ci.cmake: test JSON_DisableTupleReferenceConversion in ci_cmake_flags,
  remove unused variables and unreachable per-compiler targets, look up
  Clang tools consistently, forward CMAKE_CXX_FLAGS to ci_module_cpp20,
  format json_literals.hpp and remove backups in ci_test_amalgamation
- BUILD.bazel: add json_literals.hpp to the single-header target
- workflows: format json_literals.hpp before copying it, drop the obsolete
  natvis --version plumbing, name natvis and macro_builder in failure
  messages, drop the duplicate amalgamation job, install Valgrind only
  where needed, republish docs on version bumps, fix stale names
- Makefile: complete .PHONY and help, check-amalgamation always restores
  the checked-in files, natvis uses its own venv, macro_builder_check
  installs astyle, clean removes the fuzzer binaries
- remove tools/amalgamate/config_json_view.json (json_view.hpp is not on
  develop yet)

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

* Fix inaccuracies in the documentation

- version history: json_base_class_t (3.11.3), JSON_HAS_CPP_11 (3.10.0),
  JSON_HAS_RANGES exclusions, define-type macros, ABI tags
- releases: 3.12.0 raised the minimum CMake version
- from_*: the (ptr, len) overloads are deleted, not removed, in 4.0.0
- contains/count/find: document the deleted integral overloads
- add JSON_HAS_RANGE_VIEW_CONVERSION and list the JSON_HAS_* macros in
  the macro overview
- mention BON8 and error_handler where binary formats are listed
- broken links, outdated URLs, warning count, Hunter v0.26.12
- copy_markdown_source hook: expand snippets in the Markdown copies

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

* Pass /EHsc to the Windows C++20 module build

ci_module_cpp20 now forwards CMAKE_CXX_FLAGS to the module build. The
Windows workflow sets CMAKE_CXX_FLAGS, which replaces CMake's MSVC
defaults including /EHsc, so <chrono> failed with C4530 under /WX.

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-10-11 08:21:51 +02:00
Niels Lohmann 3901b223e5 Complete the architecture documentation page (#5570)
* Complete the architecture documentation page

Replace the placeholder bullets and TODOs with a description of the
component pipeline (with a diagram), the source layout, the template
parameters, the value storage (now in struct data), the input and
output adapters, and the SAX interface.

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

* Link sources and basic_json, document full input adapter interface

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

* Align the default column of the template parameter table

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

---------

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-25 08:28:00 +02:00
Niels Lohmann 26cfec34be Clean up and document project files (#4560) 2025-01-17 06:53:35 +01:00