to_cbor/to_msgpack/to_ubjson/to_bjdata/to_bson wrote every byte through
output_adapter_t, a shared_ptr<output_adapter_protocol> whose
write_character/write_characters are virtual. Unlike the lexer (templated
on a concrete InputAdapterType), the binary writer never got that
treatment, so binary output paid a vtable lookup per byte and a
make_shared per call.
Template binary_writer on an OutputSinkType and give it two concrete,
non-virtual sinks:
- output_vector_sink: appends straight into a std::vector (push_back /
insert), used by the vector-returning to_* convenience functions. No
vtable, no shared_ptr; the writes inline.
- output_adapter_sink: forwards to a type-erased output_adapter_t, so the
existing to_*(j, output_adapter) overloads (streams, strings, custom
adapters) keep working exactly as before -- one virtual call each,
unchanged.
binary_writer keeps a convenience constructor taking output_adapter_t
(building the default output_adapter_sink), so the adapter overloads are
untouched; only the convenience functions switch to the vector sink. The
friend declaration and the basic_json binary_writer alias gain the new
(defaulted) template parameter.
Output is byte-for-byte identical: verified across ~3000 randomized
values plus curated edge cases (all scalar widths, strings with invalid
UTF-8, binary, nested arrays/objects) for CBOR, MessagePack, UBJSON (both
size/type settings), BJData, and BSON, plus the output_adapter path, in
C++11/17/20. Warning-clean under clang -Weverything and the gcc pedantic
set; clang-tidy clean on the changed headers; make check-amalgamation
clean.
Throughput (g++ -O3, vs develop): scalar-dense binary output such as
integer arrays ~1.4x; many small to_cbor calls ~1.04x (DOM traversal
bound); string/blob-heavy output unchanged (already bulk-bound). No
workload regressed.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01XAYM1qhSA2FDaDcGfPW3fG
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
* Add versioned inline namespace
Add a versioned inline namespace to prevent ABI issues when linking code
using multiple library versions.
* Add namespace macros
* Encode ABI information in inline namespace
Add _diag suffix to inline namespace if JSON_DIAGNOSTICS is enabled, and
_ldvcmp suffix if JSON_USE_LEGACY_DISCARDED_VALUE_COMPARISON is enabled.
* Move ABI-affecting macros into abi_macros.hpp
* Move std_fs namespace definition into std_fs.hpp
* Remove std_fs namespace from unit test
* Format more files in tests directory
* Add unit tests
* Update documentation
* Fix GDB pretty printer
* fixup! Add namespace macros
* Derive ABI prefix from NLOHMANN_JSON_VERSION_*
* support UBJSON-derived Binary JData (BJData) format
* fix Codacy warning
* partially fix VS compilation errors
* fix additional VS errors
* fix more VS compilation errors
* fix additional warnings and errors for clang and msvc
* add more tests to cover the new bjdata types
* add tests for optimized ndarray, improve coverage, fix clang/gcc warnings
* gcc warn useless conversion but msvc gives an error
* fix ci_test errors
* complete test coverage, fix ci_test errors
* add half precision error test
* fix No newline at end of file error by clang
* simplify endian condition, format unit-bjdata
* remove broken test due to alloc limit
* full coverage, I hope
* move bjdata new markers from default to the same level as ubjson markers
* fix ci errors, add tests for new bjdata switch structure
* make is_bjdata const after using initializer list
* remove the unwanted assert
* move is_bjdata to an optional param to write_ubjson
* pass use_bjdata via output adapter
* revert order to avoid msvc 2015 unreferenced formal param error
* update BJData Spect V1 Draft-2 URL after spec release
* amalgamate code
* code polishing following @gregmarr's feedback
* make use_bjdata a non-default parameter
* fix ci error, remove unwanted param comment
* encode and decode bjdata ndarray in jdata annotations, enable roundtrip tests
* partially fix ci errors, add tests to improve coverage
* polish patch to remove ci errors
* fix a ndarray dim vector condition
* fix clang tidy error
* add sax test cases for ndarray
* add additional sax event tests
* adjust sax event numbering
* fix sax tests
* ndarray can only be used with array containers, discard if used in object
* complete test coverage
* disable [{SHTFNZ in optimized type due to security risks in #2793 and hampered readability
* fix ci error
* move OutputIsLittleEndian from tparam to param to replace use_bjdata
* fix ci clang gcc error
* fix ci static analysis error
* update json_test_data to 3.1.0, enable file-based bjdata unit tests
* fix stack overflow error on msvc 2019 and 2022
* use https link, update sax_parse_error after rebase
* make input_format const and use initializer
* return bool for write_bjdata_ndarray
* test write_bjdata_ndarray return value as boolean
* fix ci error
* Make exception context optional
Change exception context parameter to pointer and replace context with
nullptr where appropriate.
* Support escaping other string types
* Add string concatenation function
Add variadic concat() function for concatenating char *, char, and
string types.
* Replace string concatenations using + with concat()
* Template json_pointer on string type
Change json_pointer from being templated on basic_json to being
templated on string type.
* Add unit test for #3388Closes#3388.
* Fix regression test for #2958
* Add backwards compatibility with json_pointer<basic_json>
* Update json_pointer docs
* Allow comparing different json_pointers
* Update version numbers
Niels LohmannandClaude Opus 4.8
NmPassTHFanandGitHub
Michael ValladolidandGitHub
Nebojša CvetkovićandGitHub
Qianqian FangandGitHub
Niels LohmannandGitHub
Alex BeregszasziandGitHub
Pierre Hallot
Ferry Huberts
Sven Fink
Matthew Bauer