1 /* Variable-sized buffer with on-stack default allocation.
2 Copyright (C) 2015-2023 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 <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
26 bool
27 __libc_scratch_buffer_grow (struct scratch_buffer *buffer)
28 {
29 void *new_ptr;
30 size_t new_length = buffer->length * 2;
31
32 /* Discard old buffer. */
33 scratch_buffer_free (buffer);
34
35 /* Check for overflow. */
36 if (__glibc_likely (new_length >= buffer->length))
37 new_ptr = malloc (new_length);
38 else
39 {
40 __set_errno (ENOMEM);
41 new_ptr = NULL;
42 }
43
44 if (__glibc_unlikely (new_ptr == NULL))
45 {
46 /* Buffer must remain valid to free. */
47 scratch_buffer_init (buffer);
48 return false;
49 }
50
51 /* Install new heap-based buffer. */
52 buffer->data = new_ptr;
53 buffer->length = new_length;
54 return true;
55 }
56 libc_hidden_def (__libc_scratch_buffer_grow)