Niels Lohmann 2f817b9174 SWAR: test for special bytes in the reduced form ...

The usual test for a zero byte, (x - ones) & ~x & high, needs `& ~x` only
to keep bytes from 0x80 out. The tests for quotes, backslashes and control
characters in string_scan.hpp and the serializer also flag every byte from
0x80 with `v & high`, so the `& ~x` terms can be dropped. Clang finds this
reduction itself; GCC does not and emits 24 instead of 16 instructions.

The masks are the same for 1.3 billion random words and for every pair of
adjacent byte values. With GCC 15 on x86-64: accept() -2 to -4 %,
sax_parse() -2 %, dump() -3 %. Clang is unchanged.

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

2026-11-06 12:17:57 +01:00

..

detail

SWAR: test for special bytes in the reduced form

2026-11-06 12:17:57 +01:00

thirdparty/hedley

Undefine the four JSON_HEDLEY_* macros that leak after including json.hpp (#5475)

2026-09-09 09:48:17 +02:00

adl_serializer.hpp

📄 adjust year (#5044)

2026-01-01 20:00:39 +01:00

byte_container_with_subtype.hpp

📄 adjust year (#5044)

2026-01-01 20:00:39 +01:00

json_fwd.hpp

Fix CI jobs that check less than they claim; move arm64 to GitHub (#5733)

2026-09-30 22:49:24 +02:00

json_literals.hpp

Move the user-defined string literals to <nlohmann/json_literals.hpp> and add JSON_NO_AUTOMATIC_UDLS (#5610)

2026-09-30 20:08:17 +02:00

json_view.hpp

Raise line coverage to 99.9 %: fix the measurement, remove unreachable code, add tests (#5997)

2026-11-02 17:54:38 +01:00

json.hpp

Parse JSON in one block of memory with a fused pointer-based parser

2026-11-06 06:56:55 +01:00

ordered_map.hpp

Consolidate duplicated detail helpers and bodies (#5891) (#5901)

2026-10-25 06:17:50 +01:00