1 /**************************************************************************
3 * Copyright 2008-2010 VMware, Inc.
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
26 **************************************************************************/
30 * Memory alignment wrappers.
35 #error "Must not be included directly. Include os_memory.h instead"
39 #include "pipe/p_compiler.h"
44 * Add two size_t values with integer overflow check.
45 * TODO: leverage __builtin_add_overflow where available
48 add_overflow_size_t(size_t a
, size_t b
, size_t *res
)
51 return *res
< a
|| *res
< b
;
56 * Return memory on given byte alignment
59 os_malloc_aligned(size_t size
, size_t alignment
)
67 * alloc_size = size + alignment + sizeof(void *)
69 * while checking for overflow.
71 if (add_overflow_size_t(size
, alignment
, &alloc_size
) ||
72 add_overflow_size_t(alloc_size
, sizeof(void *), &alloc_size
)) {
76 ptr
= (char *) os_malloc(alloc_size
);
80 buf
= (char *)(((uintptr_t)ptr
+ sizeof(void *) + alignment
- 1) & ~((uintptr_t)(alignment
- 1)));
81 *(char **)(buf
- sizeof(void *)) = ptr
;
88 * Free memory returned by os_malloc_aligned().
91 os_free_aligned(void *ptr
)
94 void **cubbyHole
= (void **) ((char *) ptr
- sizeof(void *));
95 void *realAddr
= *cubbyHole
;