2 * SPDX-License-Identifier: MIT
4 * Copyright (c) 2005-2014 Rich Felker, et al.
6 * Permission is hereby granted, free of charge, to any person obtaining
7 * a copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sublicense, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
14 * The above copyright notice and this permission notice shall be
15 * included in all copies or substantial portions of the Software.
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
18 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
19 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
20 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
21 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
22 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
23 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 #include <sys/cdefs.h>
26 __FBSDID("$FreeBSD$");
32 #define SS (sizeof(size_t))
33 #define ALIGN (sizeof(size_t)-1)
34 #define ONES ((size_t)-1/UCHAR_MAX)
35 #define HIGHS (ONES * (UCHAR_MAX/2+1))
36 #define HASZERO(x) (((x)-ONES) & ~(x) & HIGHS)
38 void *memchr(const void *src, int c, size_t n)
40 const unsigned char *s = src;
43 for (; ((uintptr_t)s & ALIGN) && n && *s != c; s++, n--);
45 typedef size_t __attribute__((__may_alias__)) word;
48 for (w = (const void *)s; n>=SS && !HASZERO(*w^k); w++, n-=SS);
52 for (; n && *s != c; s++, n--);
53 return n ? (void *)s : 0;