cosmopolitan/libc/str/stpncpy.c

43 lines
2.5 KiB
C

/*-*- 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. Consider trying
* memccpy() for that purpose.
*
* @return dest + stride
* @see stncpy(), memccpy()
* @asyncsignalsafe
*/
char *stpncpy(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 + stride;
}