glibc/malloc/scratch_buffer_grow.c

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/* Variable-sized buffer with on-stack default allocation.
Copyright (C) 2015-2019 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#ifndef _LIBC
# include <libc-config.h>
#endif
#include <scratch_buffer.h>
#include <errno.h>
bool
__libc_scratch_buffer_grow (struct scratch_buffer *buffer)
{
void *new_ptr;
size_t new_length = buffer->length * 2;
/* Discard old buffer. */
scratch_buffer_free (buffer);
/* Check for overflow. */
if (__glibc_likely (new_length >= buffer->length))
new_ptr = malloc (new_length);
else
{
__set_errno (ENOMEM);
new_ptr = NULL;
}
if (__glibc_unlikely (new_ptr == NULL))
{
/* Buffer must remain valid to free. */
scratch_buffer_init (buffer);
return false;
}
/* Install new heap-based buffer. */
buffer->data = new_ptr;
buffer->length = new_length;
return true;
}
libc_hidden_def (__libc_scratch_buffer_grow)