cosmopolitan/libc/str/strncpy.c

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2020-06-15 14:18:57 +00:00
/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8 :vi
Copyright 2020 Justine Alexandra Roberts Tunney
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License.
This program 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
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
*/
#include "libc/str/str.h"
/**
* Prepares static search buffer.
*
* 1. If SRC is too long, it's truncated and *not* NUL-terminated.
* 2. If SRC is too short, the remainder is zero-filled.
*
* Please note this function isn't designed to prevent untrustworthy
* data from modifying memory without authorization; the memccpy()
* function can be used for that purpose.
*
* @return dest
* @see stpncpy(), memccpy()
* @asyncsignalsafe
*/
char *(strncpy)(char *dest, const char *src, size_t stride) {
char *p;
if ((p = memccpy(dest, src, '\0', stride))) {
memset(p, 0, dest + stride - p);
}
return dest;
}