Yukihiro "Matz" Matsumoto 337b5906a2 mruby-regexp: add first-byte bitmap for fast position skipping ...

Compute a 128-bit bitmap of bytes that could start a match.
For patterns like /cat|dog|fox/ the bitmap contains only {b,c,d,f},
skipping positions where no alternative can match. For /\d+/ only
{'0'-'9'} are set.

Used when no literal prefix is available (alternation, character
class patterns). Falls back gracefully when too many bytes match.

Key improvements vs CRuby ratio:
  alternation miss: 9.5x -> 3.6x
  \d+ medium string: 3.0x -> 1.4x

Co-authored-by: Claude <noreply@anthropic.com>

2026-04-23 19:25:33 +09:00

..

re_internal.h

mruby-regexp: add first-byte bitmap for fast position skipping

2026-04-23 19:25:33 +09:00