From 0b44a0315b47dd8eced9f3b7f31580cf14bbfc01 Mon Sep 17 00:00:00 2001 From: Rich Felker Date: Sat, 12 Feb 2011 00:22:29 -0500 Subject: initial check-in, version 0.5.0 --- src/string/stpncpy.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) create mode 100644 src/string/stpncpy.c (limited to 'src/string/stpncpy.c') diff --git a/src/string/stpncpy.c b/src/string/stpncpy.c new file mode 100644 index 00000000..a877f5fe --- /dev/null +++ b/src/string/stpncpy.c @@ -0,0 +1,32 @@ +#include +#include +#include +#include +#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); + -- cgit v1.2.1