xref: /third_party/mesa3d/src/util/reallocarray.h (revision bf215546)
1/*
2 * Copyright (c) 2022 Red Hat
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
21 * IN THE SOFTWARE.
22 */
23
24#ifndef REALLOCARRAY_H
25#define REALLOCARRAY_H
26
27#if !defined(HAVE_REALLOCARRAY)
28
29#include <stdlib.h> // size_t
30#include <errno.h>
31
32#ifdef __cplusplus
33extern "C" {
34#endif
35
36/* taken from the X server */
37/*
38 * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
39 * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
40 */
41#define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
42
43static inline void *
44reallocarray(void *optr, size_t nmemb, size_t size)
45{
46        if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
47            nmemb > 0 && SIZE_MAX / nmemb < size) {
48                errno = ENOMEM;
49                return NULL;
50        }
51        return realloc(optr, size * nmemb);
52}
53
54#ifdef __cplusplus
55}
56#endif
57
58#endif /* !defined(HAVE_REALLOCARRAY) */
59
60#endif /* REALLOCARRAY_H */
61