1/* Array allocation from a fixed-size buffer.
2 Copyright (C) 2017-2023 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#include <alloc_buffer.h>
20#include <libc-pointer-arith.h>
21
22void *
23__libc_alloc_buffer_alloc_array (struct alloc_buffer *buf, size_t element_size,
24 size_t align, size_t count)
25{
26 uintptr_t current = buf->__alloc_buffer_current;
27 /* The caller asserts that align is a power of two. */
28 uintptr_t aligned = ALIGN_UP (current, align);
29 size_t size;
30 bool overflow = __builtin_mul_overflow (element_size, count, &size);
31 uintptr_t new_current = aligned + size;
32 if (!overflow /* Multiplication did not overflow. */
33 && aligned >= current /* No overflow in align step. */
34 && new_current >= size /* No overflow in size computation. */
35 && new_current <= buf->__alloc_buffer_end) /* Room in buffer. */
36 {
37 buf->__alloc_buffer_current = new_current;
38 return (void *) aligned;
39 }
40 else
41 {
42 alloc_buffer_mark_failed (buf);
43 return NULL;
44 }
45}
46libc_hidden_def (__libc_alloc_buffer_alloc_array)
47