1 | /* Array allocation from a fixed-size buffer. |
2 | Copyright (C) 2017-2018 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 | <http://www.gnu.org/licenses/>. */ |
18 | |
19 | #include <alloc_buffer.h> |
20 | #include <malloc-internal.h> |
21 | #include <libc-pointer-arith.h> |
22 | |
23 | void * |
24 | __libc_alloc_buffer_alloc_array (struct alloc_buffer *buf, size_t element_size, |
25 | size_t align, size_t count) |
26 | { |
27 | size_t current = buf->__alloc_buffer_current; |
28 | /* The caller asserts that align is a power of two. */ |
29 | size_t aligned = ALIGN_UP (current, align); |
30 | size_t size; |
31 | bool overflow = check_mul_overflow_size_t (element_size, count, &size); |
32 | size_t new_current = aligned + size; |
33 | if (!overflow /* Multiplication did not overflow. */ |
34 | && aligned >= current /* No overflow in align step. */ |
35 | && new_current >= size /* No overflow in size computation. */ |
36 | && new_current <= buf->__alloc_buffer_end) /* Room in buffer. */ |
37 | { |
38 | buf->__alloc_buffer_current = new_current; |
39 | return (void *) aligned; |
40 | } |
41 | else |
42 | { |
43 | alloc_buffer_mark_failed (buf); |
44 | return NULL; |
45 | } |
46 | } |
47 | libc_hidden_def (__libc_alloc_buffer_alloc_array) |
48 | |