Mercurial > molko
comparison extern/libcompat/src/recallocarray.c @ 258:f978fa0137ce
extern: provide libcompat
author | David Demelier <markand@malikania.fr> |
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date | Sat, 05 Dec 2020 15:57:02 +0100 |
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257:251de91394b7 | 258:f978fa0137ce |
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1 /* $OpenBSD: recallocarray.c,v 1.1 2017/03/06 18:44:21 otto Exp $ */ | |
2 /* | |
3 * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net> | |
4 * | |
5 * Permission to use, copy, modify, and distribute this software for any | |
6 * purpose with or without fee is hereby granted, provided that the above | |
7 * copyright notice and this permission notice appear in all copies. | |
8 * | |
9 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES | |
10 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF | |
11 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR | |
12 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES | |
13 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN | |
14 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF | |
15 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
16 */ | |
17 | |
18 #include <errno.h> | |
19 #include <stdlib.h> | |
20 #include <stdint.h> | |
21 #include <string.h> | |
22 #include <unistd.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 ((size_t)1 << (sizeof(size_t) * 4)) | |
29 | |
30 void * | |
31 recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size) | |
32 { | |
33 size_t oldsize, newsize; | |
34 void *newptr; | |
35 | |
36 if (ptr == NULL) | |
37 return calloc(newnmemb, size); | |
38 | |
39 if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && | |
40 newnmemb > 0 && SIZE_MAX / newnmemb < size) { | |
41 errno = ENOMEM; | |
42 return NULL; | |
43 } | |
44 newsize = newnmemb * size; | |
45 | |
46 if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) && | |
47 oldnmemb > 0 && SIZE_MAX / oldnmemb < size) { | |
48 errno = EINVAL; | |
49 return NULL; | |
50 } | |
51 oldsize = oldnmemb * size; | |
52 | |
53 newptr = malloc(newsize); | |
54 if (newptr == NULL) | |
55 return NULL; | |
56 | |
57 if (newsize > oldsize) { | |
58 memcpy(newptr, ptr, oldsize); | |
59 memset((char *)newptr + oldsize, 0, newsize - oldsize); | |
60 } else | |
61 memcpy(newptr, ptr, newsize); | |
62 | |
63 memset(ptr, 0, oldsize); | |
64 free(ptr); | |
65 | |
66 return newptr; | |
67 } |