1#define _BSD_SOURCE
 2#include <string.h>
 3#include <stdint.h>
 4#include <limits.h>
 5
 6#define ALIGN (sizeof(size_t)-1)
 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
11size_t strlcpy(char *d, const char *s, size_t n)
12{
13	char *d0 = d;
14	size_t *wd;
15
16	if (!n--) goto finish;
17#ifdef __GNUC__
18	typedef size_t __attribute__((__may_alias__)) word;
19	const word *ws;
20	if (((uintptr_t)s & ALIGN) == ((uintptr_t)d & ALIGN)) {
21		for (; ((uintptr_t)s & ALIGN) && n && (*d=*s); n--, s++, d++);
22		if (n && *s) {
23			wd=(void *)d; ws=(const void *)s;
24			for (; n>=sizeof(size_t) && !HASZERO(*ws);
25			       n-=sizeof(size_t), ws++, wd++) *wd = *ws;
26			d=(void *)wd; s=(const void *)ws;
27		}
28	}
29#endif
30	for (; n && (*d=*s); n--, s++, d++);
31	*d = 0;
32finish:
33	return d-d0 + strlen(s);
34}