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cfcfd461 | 1 | /* Variable-sized buffer with on-stack default allocation. |
f7a9f785 | 2 | Copyright (C) 2015-2016 Free Software Foundation, Inc. |
cfcfd461 FW |
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 Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 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 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
16 | License along with the GNU C Library; if not, see | |
17 | <http://www.gnu.org/licenses/>. */ | |
18 | ||
19 | #include <scratch_buffer.h> | |
20 | #include <errno.h> | |
21 | ||
22 | bool | |
23 | __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer, | |
24 | size_t nelem, size_t size) | |
25 | { | |
26 | size_t new_length = nelem * size; | |
27 | ||
28 | /* Avoid overflow check if both values are small. */ | |
29 | if ((nelem | size) >> (sizeof (size_t) * CHAR_BIT / 2) != 0 | |
30 | && nelem != 0 && size != new_length / nelem) | |
31 | { | |
32 | /* Overflow. Discard the old buffer, but it must remain valid | |
33 | to free. */ | |
34 | scratch_buffer_free (buffer); | |
35 | scratch_buffer_init (buffer); | |
36 | __set_errno (ENOMEM); | |
37 | return false; | |
38 | } | |
39 | ||
40 | if (new_length <= buffer->length) | |
41 | return true; | |
42 | ||
43 | /* Discard old buffer. */ | |
44 | scratch_buffer_free (buffer); | |
45 | ||
46 | char *new_ptr = malloc (new_length); | |
47 | if (new_ptr == NULL) | |
48 | { | |
49 | /* Buffer must remain valid to free. */ | |
50 | scratch_buffer_init (buffer); | |
51 | return false; | |
52 | } | |
53 | ||
54 | /* Install new heap-based buffer. */ | |
55 | buffer->data = new_ptr; | |
56 | buffer->length = new_length; | |
57 | return true; | |
58 | } | |
59 | libc_hidden_def (__libc_scratch_buffer_set_array_size); |