1 #include "libc.h" 2 #include <limits.h> 3 #include <stdint.h> 4 #include <string.h> 5 6 #define ALIGN (sizeof(size_t)) 7 #define ONES ((size_t)-1 / UCHAR_MAX) 8 #define HIGHS (ONES * (UCHAR_MAX / 2 + 1)) 9 #define HASZERO(x) (((x)-ONES) & ~(x)&HIGHS) 10 __stpcpy(char * restrict d,const char * restrict s)11char* __stpcpy(char* restrict d, const char* restrict s) { 12 #if !__has_feature(address_sanitizer) 13 // This reads past the end of the string, which is usually OK since 14 // it won't cross a page boundary. But under ASan, even one byte 15 // past the actual end is diagnosed. 16 if ((uintptr_t)s % ALIGN == (uintptr_t)d % ALIGN) { 17 for (; (uintptr_t)s % ALIGN; s++, d++) 18 if (!(*d = *s)) 19 return d; 20 size_t* wd = (void*)d; 21 const size_t* ws = (const void*)s; 22 for (; !HASZERO(*ws); *wd++ = *ws++) 23 ; 24 d = (void*)wd; 25 s = (const void*)ws; 26 } 27 #endif 28 for (; (*d = *s); s++, d++) 29 ; 30 31 return d; 32 } 33 34 weak_alias(__stpcpy, stpcpy); 35