find_indexed() compared the key of a member the table points to with
memcmp, a library call for any length. Up to 16 bytes, the bytes are now
compared as two overlapping words (the first and the last 8, 4, or 2 bytes),
as find_member() already does for the objects without a table; longer keys
still use memcmp.
Looking up every key of an object of 1000 random keys, Apple M1 instructions per 1000 lookups
(with the previous commit): keys of 5 bytes 93 K -> 72 K, hex strings of 8 bytes 168 K -> 148 K,
keys of 12 bytes 186 K -> 170 K, keys of 24 bytes 198 K -> 193 K (unchanged, memcmp).
Linux x86-64 Ir (whole run), GCC 13 / Clang 18: 5-byte keys -7.2 % / -7.3 %, 12-byte keys -5.9 % / -6.6 %.
Belongs to the PR "json_view: read-side speedups".
Signed-off-by: Niels Lohmann <mail@nlohmann.me>
Niels Lohmann
cc3b16f3b8