1 /*
2 * Copyright (c) 2016, Alliance for Open Media. All rights reserved
3 *
4 * This source code is subject to the terms of the BSD 2 Clause License and
5 * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
6 * was not distributed with this source code in the LICENSE file, you can
7 * obtain it at www.aomedia.org/license/software. If the Alliance for Open
8 * Media Patent License 1.0 was not distributed with this source code in the
9 * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
10 */
11
12 #include "aom_mem.h"
13 #include <assert.h>
14 #include <stdlib.h>
15 #include <string.h>
16 #include "include/aom_mem_intrnl.h"
17 #include "aom/aom_integer.h"
18
GetAllocationPaddingSize(size_t align)19 static size_t GetAllocationPaddingSize(size_t align) {
20 assert(align > 0);
21 assert(align < SIZE_MAX - ADDRESS_STORAGE_SIZE);
22 return align - 1 + ADDRESS_STORAGE_SIZE;
23 }
24
25 // Returns 0 in case of overflow of nmemb * size.
check_size_argument_overflow(size_t nmemb,size_t size,size_t align)26 static int check_size_argument_overflow(size_t nmemb, size_t size,
27 size_t align) {
28 if (nmemb == 0) return 1;
29 const size_t alloc_padding = GetAllocationPaddingSize(align);
30 #if defined(AOM_MAX_ALLOCABLE_MEMORY)
31 assert(AOM_MAX_ALLOCABLE_MEMORY >= alloc_padding);
32 assert(AOM_MAX_ALLOCABLE_MEMORY <= SIZE_MAX);
33 if (size > (AOM_MAX_ALLOCABLE_MEMORY - alloc_padding) / nmemb) return 0;
34 #else
35 if (size > (SIZE_MAX - alloc_padding) / nmemb) return 0;
36 #endif
37 return 1;
38 }
39
GetMallocAddressLocation(void * const mem)40 static size_t *GetMallocAddressLocation(void *const mem) {
41 return ((size_t *)mem) - 1;
42 }
43
SetActualMallocAddress(void * const mem,const void * const malloc_addr)44 static void SetActualMallocAddress(void *const mem,
45 const void *const malloc_addr) {
46 size_t *const malloc_addr_location = GetMallocAddressLocation(mem);
47 *malloc_addr_location = (size_t)malloc_addr;
48 }
49
GetActualMallocAddress(void * const mem)50 static void *GetActualMallocAddress(void *const mem) {
51 const size_t *const malloc_addr_location = GetMallocAddressLocation(mem);
52 return (void *)(*malloc_addr_location);
53 }
54
aom_memalign(size_t align,size_t size)55 void *aom_memalign(size_t align, size_t size) {
56 void *x = NULL;
57 if (!check_size_argument_overflow(1, size, align)) return NULL;
58 const size_t aligned_size = size + GetAllocationPaddingSize(align);
59 void *const addr = malloc(aligned_size);
60 if (addr) {
61 x = aom_align_addr((unsigned char *)addr + ADDRESS_STORAGE_SIZE, align);
62 SetActualMallocAddress(x, addr);
63 }
64 return x;
65 }
66
aom_malloc(size_t size)67 void *aom_malloc(size_t size) { return aom_memalign(DEFAULT_ALIGNMENT, size); }
68
aom_calloc(size_t num,size_t size)69 void *aom_calloc(size_t num, size_t size) {
70 if (!check_size_argument_overflow(num, size, DEFAULT_ALIGNMENT)) return NULL;
71 const size_t total_size = num * size;
72 void *const x = aom_malloc(total_size);
73 if (x) memset(x, 0, total_size);
74 return x;
75 }
76
aom_free(void * memblk)77 void aom_free(void *memblk) {
78 if (memblk) {
79 void *addr = GetActualMallocAddress(memblk);
80 free(addr);
81 }
82 }
83