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1 /*
2  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
3  *
4  *  Use of this source code is governed by a BSD-style license
5  *  that can be found in the LICENSE file in the root of the source
6  *  tree. An additional intellectual property rights grant can be found
7  *  in the file PATENTS.  All contributing project authors may
8  *  be found in the AUTHORS file in the root of the source tree.
9  */
10 
11 #include "vpx_mem.h"
12 #include <limits.h>
13 #include <stdio.h>
14 #include <stdlib.h>
15 #include <string.h>
16 #include "include/vpx_mem_intrnl.h"
17 #include "vpx/vpx_integer.h"
18 
19 #if !defined(VPX_MAX_ALLOCABLE_MEMORY)
20 #if SIZE_MAX > (1ULL << 40)
21 #define VPX_MAX_ALLOCABLE_MEMORY (1ULL << 40)
22 #else
23 // For 32-bit targets keep this below INT_MAX to avoid valgrind warnings.
24 #define VPX_MAX_ALLOCABLE_MEMORY ((1ULL << 31) - (1 << 16))
25 #endif
26 #endif
27 
28 // Returns 0 in case of overflow of nmemb * size.
check_size_argument_overflow(uint64_t nmemb,uint64_t size)29 static int check_size_argument_overflow(uint64_t nmemb, uint64_t size) {
30   const uint64_t total_size = nmemb * size;
31   if (nmemb == 0) return 1;
32   if (size > VPX_MAX_ALLOCABLE_MEMORY / nmemb) return 0;
33   if (total_size != (size_t)total_size) return 0;
34 
35   return 1;
36 }
37 
get_malloc_address_location(void * const mem)38 static size_t *get_malloc_address_location(void *const mem) {
39   return ((size_t *)mem) - 1;
40 }
41 
get_aligned_malloc_size(size_t size,size_t align)42 static uint64_t get_aligned_malloc_size(size_t size, size_t align) {
43   return (uint64_t)size + align - 1 + ADDRESS_STORAGE_SIZE;
44 }
45 
set_actual_malloc_address(void * const mem,const void * const malloc_addr)46 static void set_actual_malloc_address(void *const mem,
47                                       const void *const malloc_addr) {
48   size_t *const malloc_addr_location = get_malloc_address_location(mem);
49   *malloc_addr_location = (size_t)malloc_addr;
50 }
51 
get_actual_malloc_address(void * const mem)52 static void *get_actual_malloc_address(void *const mem) {
53   size_t *const malloc_addr_location = get_malloc_address_location(mem);
54   return (void *)(*malloc_addr_location);
55 }
56 
vpx_memalign(size_t align,size_t size)57 void *vpx_memalign(size_t align, size_t size) {
58   void *x = NULL, *addr;
59   const uint64_t aligned_size = get_aligned_malloc_size(size, align);
60   if (!check_size_argument_overflow(1, aligned_size)) return NULL;
61 
62   addr = malloc((size_t)aligned_size);
63   if (addr) {
64     x = align_addr((unsigned char *)addr + ADDRESS_STORAGE_SIZE, align);
65     set_actual_malloc_address(x, addr);
66   }
67   return x;
68 }
69 
vpx_malloc(size_t size)70 void *vpx_malloc(size_t size) { return vpx_memalign(DEFAULT_ALIGNMENT, size); }
71 
vpx_calloc(size_t num,size_t size)72 void *vpx_calloc(size_t num, size_t size) {
73   void *x;
74   if (!check_size_argument_overflow(num, size)) return NULL;
75 
76   x = vpx_malloc(num * size);
77   if (x) memset(x, 0, num * size);
78   return x;
79 }
80 
vpx_free(void * memblk)81 void vpx_free(void *memblk) {
82   if (memblk) {
83     void *addr = get_actual_malloc_address(memblk);
84     free(addr);
85   }
86 }
87