From: Benjamin Kramer Date: Tue, 26 Jan 2010 17:48:36 GMT Subject: [PATCH] grep: use REG_STARTEND (if available) to speed up regexec Message-ID: <4B5F2AF4.2090307@googlemail.com> In-Reply-To: BSD and glibc have an extension to regexec which takes a buffer + length pair instead of a NUL-terminated string. Since we already have the length computed this can save us a strlen call inside regexec. Signed-off-by: Benjamin Kramer Acked-by: Linus Torvalds --- Resend of my previous patch with SOB and correct title. grep.c | 9 ++++++++- 1 files changed, 8 insertions(+), 1 deletions(-) diff --git a/grep.c b/grep.c index 8e1f7de..452c2cb 100644 --- a/grep.c +++ b/grep.c @@ -640,8 +640,15 @@ static int look_ahead(struct grep_opt *opt, if (p->fixed) hit = !fixmatch(p->pattern, bol, p->ignore_case, &m); - else + else { +#ifdef REG_STARTEND + m.rm_so = 0; + m.rm_eo = *left_p; + hit = !regexec(&p->regexp, bol, 1, &m, REG_STARTEND); +#else hit = !regexec(&p->regexp, bol, 1, &m, 0); +#endif + } if (!hit || m.rm_so < 0 || m.rm_eo < 0) continue; if (earliest < 0 || m.rm_so < earliest) -- 1.7.0.rc0.12.gc33c3