1 | /* Variable-sized buffer with on-stack default allocation. |
2 | Copyright (C) 2015-2016 Free Software Foundation, Inc. |
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); |
60 | |