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 __stpcpy(char * restrict d,const char * restrict s)10char *__stpcpy(char *restrict d, const char *restrict s) 11 { 12 #ifdef __GNUC__ 13 typedef size_t __attribute__((__may_alias__)) word; 14 word *wd; 15 const word *ws; 16 if ((uintptr_t)s % ALIGN == (uintptr_t)d % ALIGN) { 17 for (; (uintptr_t)s % ALIGN; s++, d++) 18 if (!(*d=*s)) return d; 19 wd=(void *)d; ws=(const void *)s; 20 for (; !HASZERO(*ws); *wd++ = *ws++); 21 d=(void *)wd; s=(const void *)ws; 22 } 23 #endif 24 for (; (*d=*s); s++, d++); 25 26 return d; 27 } 28 29 weak_alias(__stpcpy, stpcpy); 30