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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
33 extern "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 
43 static inline void *
reallocarray(void * optr,size_t nmemb,size_t size)44 reallocarray(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