Files
json/BUILD.bazel
Niels Lohmann ebfbbf29cb Scan the strings of json_view with NEON and SSE2
Long runs of string bytes are scanned 16 at a time with NEON (AArch64, with
GCC and Clang) and SSE2 (x86-64): both belong to the baseline instruction
sets. A signed compare with 0x20 finds control characters and non-ASCII
bytes at once. Keys keep 16 table checks before the vector loop (their
lengths repeat from record to record, so the branches predict well);
string values have 8, as their lengths vary more.

Non-ASCII text is validated 16 bytes at a time with the "lookup4" check of
simdjson (J. Keiser and D. Lemire, "Validating UTF-8 In Less Than One
Instruction Per Byte", 2021): with NEON, and on x86-64 with SSSE3 if
JSON_VIEW_USE_SSSE3 is defined (SSSE3 is not part of x86-64, and the code
must not depend on the flags of a translation unit). JSON_VIEW_NO_SIMD
selects the portable code. The vector code sits in
detail/view/simd.hpp; the same input is accepted either way.

json_document::parse, best of 7 runs in separate processes (M1 Max):
poet.json (CJK text) -72%, random.json -25%, twitter.json -22%,
gsoc-2018.json -20%, semanticscholar -19%, github_events -11%,
apache_builds -9.5%, canada/citm -5/-6%; lottie +4%, tree-pretty +2.5%.

Tests: every two-byte sequence and three- and four-byte sequences with
continuation bytes at the edges of their ranges, at every offset around
the vector blocks of keys and values, cut short, and long runs of text
with a damaged byte, against json::accept and json::parse. CMake builds
the parser tests again with JSON_VIEW_NO_SIMD, and on x86-64 with
JSON_VIEW_USE_SSSE3 and -mssse3; the macros are documented.

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
2026-09-29 14:03:06 +02:00

107 lines
4.5 KiB
Python

load("@rules_cc//cc:cc_library.bzl", "cc_library")
load("@rules_license//rules:license.bzl", "license")
package(
default_applicable_licenses = [":license"],
)
exports_files([
"LICENSE.MIT",
])
license(
name = "license",
license_kinds = ["@rules_license//licenses/spdx:MIT"],
license_text = "LICENSE.MIT",
)
cc_library(
name = "json",
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",
"include/nlohmann/detail/exceptions.hpp",
"include/nlohmann/detail/hash.hpp",
"include/nlohmann/detail/input/binary_reader.hpp",
"include/nlohmann/detail/input/input_adapters.hpp",
"include/nlohmann/detail/input/json_sax.hpp",
"include/nlohmann/detail/input/lexer.hpp",
"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",
"include/nlohmann/detail/iterators/iteration_proxy.hpp",
"include/nlohmann/detail/iterators/iterator_traits.hpp",
"include/nlohmann/detail/iterators/json_reverse_iterator.hpp",
"include/nlohmann/detail/iterators/primitive_iterator.hpp",
"include/nlohmann/detail/json_custom_base_class.hpp",
"include/nlohmann/detail/json_pointer.hpp",
"include/nlohmann/detail/json_ref.hpp",
"include/nlohmann/detail/macro_scope.hpp",
"include/nlohmann/detail/macro_unscope.hpp",
"include/nlohmann/detail/meta/call_std/begin.hpp",
"include/nlohmann/detail/meta/call_std/end.hpp",
"include/nlohmann/detail/meta/cpp_future.hpp",
"include/nlohmann/detail/meta/detected.hpp",
"include/nlohmann/detail/meta/identity_tag.hpp",
"include/nlohmann/detail/meta/is_sax.hpp",
"include/nlohmann/detail/meta/logic.hpp",
"include/nlohmann/detail/meta/std_fs.hpp",
"include/nlohmann/detail/meta/type_traits.hpp",
"include/nlohmann/detail/meta/void_t.hpp",
"include/nlohmann/detail/output/binary_writer.hpp",
"include/nlohmann/detail/output/output_adapters.hpp",
"include/nlohmann/detail/output/serializer.hpp",
"include/nlohmann/detail/recursion_depth_limit.hpp",
"include/nlohmann/detail/string_concat.hpp",
"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/compare.hpp",
"include/nlohmann/detail/view/document_data.hpp",
"include/nlohmann/detail/view/errors.hpp",
"include/nlohmann/detail/view/input.hpp",
"include/nlohmann/detail/view/iterator.hpp",
"include/nlohmann/detail/view/lookup.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/pointer.hpp",
"include/nlohmann/detail/view/scan.hpp",
"include/nlohmann/detail/view/serializer.hpp",
"include/nlohmann/detail/view/simd.hpp",
"include/nlohmann/detail/view/string_ref.hpp",
"include/nlohmann/detail/view/value.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",
],
includes = ["include"],
visibility = ["//visibility:public"],
)
cc_library(
name = "singleheader-json",
hdrs = [
"single_include/nlohmann/json.hpp",
"single_include/nlohmann/json_view.hpp",
],
includes = ["single_include"],
visibility = ["//visibility:public"],
)