glibc/string/strncpy.c
Wilco Dijkstra f6482cf29d This patch improves strncpy performance by using strnlen/memcpy rather than a byte loop. Performance
on bench-strncpy is 1.9-2.1x faster on average. I tried several variations, and using a tailcall and
calling memset conditionally gave the best overall results.
2015-08-05 16:24:02 +01:00

35 lines
1.1 KiB
C

/* Copyright (C) 1991-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <string.h>
#undef strncpy
#ifndef STRNCPY
#define STRNCPY strncpy
#endif
char *
STRNCPY (char *s1, const char *s2, size_t n)
{
size_t size = __strnlen (s2, n);
if (size != n)
memset (s1 + size, '\0', n - size);
return memcpy (s1, s2, size);
}
libc_hidden_builtin_def (strncpy)