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| author | Rich Felker <dalias@aerifal.cx> | 2012-08-10 23:39:32 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2012-08-10 23:39:32 -0400 |
| commit | 2b964b010e5d37cb2ff712d57a14095188d689e3 (patch) | |
| tree | f45adf47882f54a7609420164e4a3b15dbeac55d /src/stdio | |
| parent | 4c346919a9b238748de2ee85ce6d749fc3cf7059 (diff) | |
| download | musl-2b964b010e5d37cb2ff712d57a14095188d689e3.tar.gz | |
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.
Diffstat (limited to 'src/stdio')
| -rw-r--r-- | src/stdio/vfprintf.c | 6 |
1 files 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; |