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| author | Rich Felker <dalias@aerifal.cx> | 2012-09-27 16:56:33 -0400 |
|---|---|---|
| committer | Rich Felker <dalias@aerifal.cx> | 2012-09-27 16:56:33 -0400 |
| commit | 3f9ff1514e49b06c20a61af9ae9e52bd53b48d9a (patch) | |
| tree | 697589451e3d75da05df6e2dd38fcdabf5b4a138 | |
| parent | 507faa63cb12571c14d66eb37dedbe6adbbf40a8 (diff) | |
| download | musl-3f9ff1514e49b06c20a61af9ae9e52bd53b48d9a.tar.gz | |
slightly cleaner strlen, also seems to compile to better code
testing with gcc 4.6.3 on x86, -Os, the old version does a duplicate
null byte check after the first loop. this is purely the compiler
being stupid, but the old code was also stupid and unintuitive in how
it expressed the check.
| -rw-r--r-- | src/string/strlen.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/src/string/strlen.c b/src/string/strlen.c index 936fb5cf..d6f8631d 100644 --- a/src/string/strlen.c +++ b/src/string/strlen.c @@ -3,7 +3,7 @@ #include <stdint.h> #include <limits.h> -#define ALIGN (sizeof(size_t)-1) +#define ALIGN (sizeof(size_t)) #define ONES ((size_t)-1/UCHAR_MAX) #define HIGHS (ONES * (UCHAR_MAX/2+1)) #define HASZERO(x) ((x)-ONES & ~(x) & HIGHS) @@ -12,10 +12,8 @@ size_t strlen(const char *s) { const char *a = s; const size_t *w; - for (; ((uintptr_t)s & ALIGN) && *s; s++); - if (*s) { - for (w = (const void *)s; !HASZERO(*w); w++); - for (s = (const void *)w; *s; s++); - } + for (; (uintptr_t)s % ALIGN; s++) if (!*s) return s-a; + for (w = (const void *)s; !HASZERO(*w); w++); + for (s = (const void *)w; *s; s++); return s-a; } |