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#include <string.h> #include <stdlib.h> #include <stdint.h> #include <limits.h> #include "libc.h" #define ALIGN (sizeof(size_t)-1) #define ONES ((size_t)-1/UCHAR_MAX) #define HIGHS (ONES * (UCHAR_MAX/2+1)) #define HASZERO(x) ((x)-ONES & ~(x) & HIGHS) char *__stpncpy(char *d, const char *s, size_t n) { size_t *wd; const size_t *ws; if (((uintptr_t)s & ALIGN) == ((uintptr_t)d & ALIGN)) { for (; ((uintptr_t)s & ALIGN) && n && (*d=*s); n--, s++, d++); if (!n || !*s) goto tail; wd=(void *)d; ws=(const void *)s; for (; n>=sizeof(size_t) && !HASZERO(*ws); n-=sizeof(size_t), ws++, wd++) *wd = *ws; d=(void *)wd; s=(const void *)ws; } for (; n && (*d=*s); n--, s++, d++); tail: memset(d, 0, n); return d; } weak_alias(__stpncpy, stpncpy); |