Niels Lohmann 7d3412a559 Encode runs of numbers in UBJSON and BJData arrays without a call each ...

An array of numbers was written one write_ubjson() call per element, each
picking the marker of an integer by a ladder of range checks and writing it
with a switch and several small sink writes.

An array that starts with a number now encodes its runs of numbers straight
into space reserved from the sink, as the CBOR and MessagePack writers do for
integers. The marker and size of an integer come from a table indexed by the
bit length of its magnitude, and its bytes are stored as one word, so that the
code does not branch on their size; floats are stored the same way. Arrays
that do not start with a number, and a single integer, keep the previous code.
An unsigned integer UBJSON can only write as a high-precision number is left
to write_ubjson().

Instructions per call (Linux, GCC 13, thousands), to_bjdata: 20000 integers 3278 -> 1086, 20000 floats 2193 -> 1000, canada 20829 -> 16805; to_ubjson: 20000 integers 3282 -> 1246, 20000 floats 2213 -> 1020.

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

2026-10-22 09:28:49 +02:00

..

json_fwd.hpp

Scan strings with SSE2, SSSE3, or NEON (#5853)

2026-10-21 20:00:50 +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

Use standard library helpers where available, with C++11 fallbacks (#5876)

2026-10-21 20:14:59 +02:00

json.hpp

Encode runs of numbers in UBJSON and BJData arrays without a call each

2026-10-22 09:28:49 +02:00