From c822255cfc1ac83daeeeee1647e3c775450c830c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ren=C3=A9=20Scharfe?= Date: Sat, 10 Jan 2009 00:18:34 +0100 Subject: grep: don't call regexec() for fixed strings Add the new flag "fixed" to struct grep_pat and set it if the pattern is doesn't contain any regex control characters in addition to if the flag -F/--fixed-strings was specified. This gives a nice speed up on msysgit, where regexec() seems to be extra slow. Before (best of five runs): $ time git grep grep v1.6.1 >/dev/null real 0m0.552s user 0m0.000s sys 0m0.000s $ time git grep -F grep v1.6.1 >/dev/null real 0m0.170s user 0m0.000s sys 0m0.015s With the patch: $ time git grep grep v1.6.1 >/dev/null real 0m0.173s user 0m0.000s sys 0m0.000s The difference is much smaller on Linux, but still measurable. Signed-off-by: Rene Scharfe Signed-off-by: Junio C Hamano --- grep.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-) (limited to 'grep.c') diff --git a/grep.c b/grep.c index 22a56b5d54..6485760ff3 100644 --- a/grep.c +++ b/grep.c @@ -28,9 +28,31 @@ void append_grep_pattern(struct grep_opt *opt, const char *pat, p->next = NULL; } +static int isregexspecial(int c) +{ + return isspecial(c) || c == '$' || c == '(' || c == ')' || c == '+' || + c == '.' || c == '^' || c == '{' || c == '|'; +} + +static int is_fixed(const char *s) +{ + while (!isregexspecial(*s)) + s++; + return !*s; +} + static void compile_regexp(struct grep_pat *p, struct grep_opt *opt) { - int err = regcomp(&p->regexp, p->pattern, opt->regflags); + int err; + + if (opt->fixed || is_fixed(p->pattern)) + p->fixed = 1; + if (opt->regflags & REG_ICASE) + p->fixed = 0; + if (p->fixed) + return; + + err = regcomp(&p->regexp, p->pattern, opt->regflags); if (err) { char errbuf[1024]; char where[1024]; @@ -159,8 +181,7 @@ void compile_grep_patterns(struct grep_opt *opt) case GREP_PATTERN: /* atom */ case GREP_PATTERN_HEAD: case GREP_PATTERN_BODY: - if (!opt->fixed) - compile_regexp(p, opt); + compile_regexp(p, opt); break; default: opt->extended = 1; @@ -314,7 +335,7 @@ static int match_one_pattern(struct grep_opt *opt, struct grep_pat *p, char *bol } again: - if (!opt->fixed) { + if (!p->fixed) { regex_t *exp = &p->regexp; hit = !regexec(exp, bol, ARRAY_SIZE(pmatch), pmatch, 0); -- cgit v1.2.3