Commit | Line | Data |
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c0c3707f | 1 | /* Variable-sized buffer with on-stack default allocation. |
5df4cba6 | 2 | Copyright (C) 2015-2020 Free Software Foundation, Inc. |
c0c3707f CB |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 3 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <https://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #ifndef _LIBC | |
20 | # include <libc-config.h> | |
21 | #endif | |
22 | ||
23 | #include <scratch_buffer.h> | |
24 | #include <errno.h> | |
25 | #include <limits.h> | |
26 | ||
27 | bool | |
28 | __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer, | |
29 | size_t nelem, size_t size) | |
30 | { | |
31 | size_t new_length = nelem * size; | |
32 | ||
33 | /* Avoid overflow check if both values are small. */ | |
34 | if ((nelem | size) >> (sizeof (size_t) * CHAR_BIT / 2) != 0 | |
35 | && nelem != 0 && size != new_length / nelem) | |
36 | { | |
37 | /* Overflow. Discard the old buffer, but it must remain valid | |
38 | to free. */ | |
39 | scratch_buffer_free (buffer); | |
40 | scratch_buffer_init (buffer); | |
41 | __set_errno (ENOMEM); | |
42 | return false; | |
43 | } | |
44 | ||
45 | if (new_length <= buffer->length) | |
46 | return true; | |
47 | ||
48 | /* Discard old buffer. */ | |
49 | scratch_buffer_free (buffer); | |
50 | ||
51 | char *new_ptr = malloc (new_length); | |
52 | if (new_ptr == NULL) | |
53 | { | |
54 | /* Buffer must remain valid to free. */ | |
55 | scratch_buffer_init (buffer); | |
56 | return false; | |
57 | } | |
58 | ||
59 | /* Install new heap-based buffer. */ | |
60 | buffer->data = new_ptr; | |
61 | buffer->length = new_length; | |
62 | return true; | |
63 | } | |
64 | libc_hidden_def (__libc_scratch_buffer_set_array_size) |