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/* Array allocation from a fixed-size buffer.
Copyright (C) 2017-2020 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
<https://www.gnu.org/licenses/>. */
#include <alloc_buffer.h>
#include <libc-pointer-arith.h>
void *
__libc_alloc_buffer_alloc_array (struct alloc_buffer *buf, size_t element_size,
size_t align, size_t count)
{
size_t current = buf->__alloc_buffer_current;
/* The caller asserts that align is a power of two. */
size_t aligned = ALIGN_UP (current, align);
size_t size;
bool overflow = __builtin_mul_overflow (element_size, count, &size);
size_t new_current = aligned + size;
if (!overflow /* Multiplication did not overflow. */
&& aligned >= current /* No overflow in align step. */
&& new_current >= size /* No overflow in size computation. */
&& new_current <= buf->__alloc_buffer_end) /* Room in buffer. */
{
buf->__alloc_buffer_current = new_current;
return (void *) aligned;
}
else
{
alloc_buffer_mark_failed (buf);
return NULL;
}
}
libc_hidden_def (__libc_alloc_buffer_alloc_array)
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