33 lines
819 B
C
33 lines
819 B
C
#include <string.h>
|
|
#include <stdint.h>
|
|
#include <limits.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 *restrict d, const char *restrict s, size_t n)
|
|
{
|
|
#ifdef __GNUC__
|
|
typedef size_t __attribute__((__may_alias__)) word;
|
|
word *wd;
|
|
const word *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;
|
|
}
|
|
#endif
|
|
for (; n && (*d=*s); n--, s++, d++);
|
|
tail:
|
|
memset(d, 0, n);
|
|
return d;
|
|
}
|
|
|
|
weak_alias(__stpncpy, stpncpy);
|
|
|