1 /* Variable-sized buffer with on-stack default allocation.
2 Copyright (C) 2015-2018 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
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.
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.
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/>. */
20 # include <libc-config.h>
23 #include <scratch_buffer.h>
28 __libc_scratch_buffer_grow_preserve (struct scratch_buffer *buffer)
30 size_t new_length = 2 * buffer->length;
33 if (buffer->data == buffer->__space)
35 /* Move buffer to the heap. No overflow is possible because
36 buffer->length describes a small buffer on the stack. */
37 new_ptr = malloc (new_length);
40 memcpy (new_ptr, buffer->__space, buffer->length);
44 /* Buffer was already on the heap. Check for overflow. */
45 if (__glibc_likely (new_length >= buffer->length))
46 new_ptr = realloc (buffer->data, new_length);
53 if (__glibc_unlikely (new_ptr == NULL))
55 /* Deallocate, but buffer must remain valid to free. */
57 scratch_buffer_init (buffer);
62 /* Install new heap-based buffer. */
63 buffer->data = new_ptr;
64 buffer->length = new_length;
67 libc_hidden_def (__libc_scratch_buffer_grow_preserve)