reallocarray.c (1306B)
1 /*
2 * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
3 *
4 * Permission to use, copy, modify, and distribute this software for any
5 * purpose with or without fee is hereby granted, provided that the above
6 * copyright notice and this permission notice appear in all copies.
7 *
8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 */
16
17 #include <sys/types.h>
18 #include <errno.h>
19 #include <stdint.h>
20 #include <stdlib.h>
21
22 #include "compat.h"
23
24 /*
25 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
26 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
27 */
28 #define MUL_NO_OVERFLOW (1UL << (sizeof(size_t) * 4))
29
30 void *
31 reallocarray(void *optr, size_t nmemb, size_t size)
32 {
33 if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
34 nmemb > 0 && SIZE_MAX / nmemb < size) {
35 errno = ENOMEM;
36 return NULL;
37 }
38 return realloc(optr, size * nmemb);
39 }