1#include <string.h> 2#include <stdint.h> 3#include <limits.h> 4 5#define ALIGN (sizeof(size_t)) 6#define ONES ((size_t)-1/UCHAR_MAX) 7#define HIGHS (ONES * (UCHAR_MAX/2+1)) 8#define HASZERO(x) ((x)-ONES & ~(x) & HIGHS) 9 10size_t strlen(const char *s) 11{ 12 const char *a = s; 13 const size_t *w; 14 for (; (uintptr_t)s % ALIGN; s++) if (!*s) return s-a; 15 for (w = (const void *)s; !HASZERO(*w); w++); 16 for (s = (const void *)w; *s; s++); 17 return s-a; 18} 19