From 2b964b010e5d37cb2ff712d57a14095188d689e3 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Fri, 10 Aug 2012 23:39:32 -0400 Subject: [PATCH] minor but worthwhile optimization in printf: avoid expensive strspn the strspn call was made for every format specifier and end-of-string, even though the expected return value was 1-2 for normal usage. replace with simple loop. --- src/stdio/vfprintf.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/src/stdio/vfprintf.c b/src/stdio/vfprintf.c index 116e1ced..d186d58b 100644 --- a/src/stdio/vfprintf.c +++ b/src/stdio/vfprintf.c @@ -430,7 +430,7 @@ static int getint(char **s) { static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg, int *nl_type) { char *a, *z, *s=(char *)fmt; - unsigned l10n=0, litpct, fl; + unsigned l10n=0, fl; int w, p; union arg arg; int argpos; @@ -455,9 +455,7 @@ static int printf_core(FILE *f, const char *fmt, va_list *ap, union arg *nl_arg, /* Handle literal text and %% format specifiers */ for (a=s; *s && *s!='%'; s++); - litpct = strspn(s, "%")/2; /* Optimize %%%% runs */ - z = s+litpct; - s += 2*litpct; + for (z=s; s[0]=='%' && s[1]=='%'; z++, s+=2); l = z-a; if (f) out(f, a, l); if (l) continue; -- 2.25.1