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cfcfd461 | 1 | /* Variable-sized buffer with on-stack default allocation. |
bfff8b1b | 2 | Copyright (C) 2015-2017 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> | |
c04af606 | 21 | #include <limits.h> |
cfcfd461 FW |
22 | |
23 | bool | |
24 | __libc_scratch_buffer_set_array_size (struct scratch_buffer *buffer, | |
25 | size_t nelem, size_t size) | |
26 | { | |
27 | size_t new_length = nelem * size; | |
28 | ||
29 | /* Avoid overflow check if both values are small. */ | |
30 | if ((nelem | size) >> (sizeof (size_t) * CHAR_BIT / 2) != 0 | |
31 | && nelem != 0 && size != new_length / nelem) | |
32 | { | |
33 | /* Overflow. Discard the old buffer, but it must remain valid | |
34 | to free. */ | |
35 | scratch_buffer_free (buffer); | |
36 | scratch_buffer_init (buffer); | |
37 | __set_errno (ENOMEM); | |
38 | return false; | |
39 | } | |
40 | ||
41 | if (new_length <= buffer->length) | |
42 | return true; | |
43 | ||
44 | /* Discard old buffer. */ | |
45 | scratch_buffer_free (buffer); | |
46 | ||
47 | char *new_ptr = malloc (new_length); | |
48 | if (new_ptr == NULL) | |
49 | { | |
50 | /* Buffer must remain valid to free. */ | |
51 | scratch_buffer_init (buffer); | |
52 | return false; | |
53 | } | |
54 | ||
55 | /* Install new heap-based buffer. */ | |
56 | buffer->data = new_ptr; | |
57 | buffer->length = new_length; | |
58 | return true; | |
59 | } | |
60 | libc_hidden_def (__libc_scratch_buffer_set_array_size); |