mem: do not check for negative size
[libav.git] / libavutil / mem.h
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1/*
2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3 *
2912e87a 4 * This file is part of Libav.
792098c2 5 *
2912e87a 6 * Libav is free software; you can redistribute it and/or
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7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
2912e87a 11 * Libav is distributed in the hope that it will be useful,
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12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
2912e87a 17 * License along with Libav; if not, write to the Free Software
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18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
ba87f080 22 * @file
89c9ff50 23 * memory handling functions
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24 */
25
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26#ifndef AVUTIL_MEM_H
27#define AVUTIL_MEM_H
792098c2 28
1d9c2dc8 29#include <limits.h>
5bac2d0c 30#include <stdint.h>
1d9c2dc8 31
2ed6f399 32#include "attributes.h"
276fc8a4 33#include "avutil.h"
52476c1b 34
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35/**
36 * @addtogroup lavu_mem
37 * @{
38 */
39
40
8c5ed7a6 41#if defined(__ICC) && __ICC < 1200 || defined(__SUNPRO_C)
8a24e98d 42 #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v
16c2e214 43 #define DECLARE_ASM_CONST(n,t,v) const t __attribute__ ((aligned (n))) v
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44#elif defined(__TI_COMPILER_VERSION__)
45 #define DECLARE_ALIGNED(n,t,v) \
46 AV_PRAGMA(DATA_ALIGN(v,n)) \
47 t __attribute__((aligned(n))) v
48 #define DECLARE_ASM_CONST(n,t,v) \
49 AV_PRAGMA(DATA_ALIGN(v,n)) \
50 static const t __attribute__((aligned(n))) v
16c2e214 51#elif defined(__GNUC__)
8a24e98d 52 #define DECLARE_ALIGNED(n,t,v) t __attribute__ ((aligned (n))) v
365e3c78 53 #define DECLARE_ASM_CONST(n,t,v) static const t av_used __attribute__ ((aligned (n))) v
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54#elif defined(_MSC_VER)
55 #define DECLARE_ALIGNED(n,t,v) __declspec(align(n)) t v
56 #define DECLARE_ASM_CONST(n,t,v) __declspec(align(n)) static const t v
57#else
58 #define DECLARE_ALIGNED(n,t,v) t v
59 #define DECLARE_ASM_CONST(n,t,v) static const t v
60#endif
61
52476c1b 62#if AV_GCC_VERSION_AT_LEAST(3,1)
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63 #define av_malloc_attrib __attribute__((__malloc__))
64#else
65 #define av_malloc_attrib
66#endif
67
820818a3 68#if AV_GCC_VERSION_AT_LEAST(4,3)
f3e5e6f0 69 #define av_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__)))
cca6d953 70#else
f3e5e6f0 71 #define av_alloc_size(...)
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72#endif
73
792098c2 74/**
49bd8e4b 75 * Allocate a block of size bytes with alignment suitable for all
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76 * memory accesses (including vectors if available on the CPU).
77 * @param size Size in bytes for the memory block to be allocated.
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78 * @return Pointer to the allocated block, NULL if the block cannot
79 * be allocated.
0ee97f0d 80 * @see av_mallocz()
792098c2 81 */
490a022d 82void *av_malloc(size_t size) av_malloc_attrib av_alloc_size(1);
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83
84/**
b634b36f 85 * Allocate a block of size * nmemb bytes with av_malloc().
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86 * @param nmemb Number of elements
87 * @param size Size of the single element
88 * @return Pointer to the allocated block, NULL if the block cannot
89 * be allocated.
90 * @see av_malloc()
91 */
5532cf31 92av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size)
f3e5e6f0 93{
b284e1ff 94 if (!size || nmemb >= INT_MAX / size)
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95 return NULL;
96 return av_malloc(nmemb * size);
97}
98
99/**
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100 * Allocate or reallocate a block of memory.
101 * If ptr is NULL and size > 0, allocate a new block. If
102 * size is zero, free the memory block pointed to by ptr.
0ee97f0d 103 * @param ptr Pointer to a memory block already allocated with
b4ec7a5f 104 * av_realloc() or NULL.
b634b36f 105 * @param size Size in bytes of the memory block to be allocated or
66f6bab7 106 * reallocated.
b634b36f 107 * @return Pointer to a newly-reallocated block or NULL if the block
89c9ff50 108 * cannot be reallocated or the function is used to free the memory block.
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109 * @warning Pointers originating from the av_malloc() family of functions must
110 * not be passed to av_realloc(). The former can be implemented using
111 * memalign() (or other functions), and there is no guarantee that
112 * pointers from such functions can be passed to realloc() at all.
113 * The situation is undefined according to POSIX and may crash with
114 * some libc implementations.
0ee97f0d 115 * @see av_fast_realloc()
792098c2 116 */
490a022d 117void *av_realloc(void *ptr, size_t size) av_alloc_size(2);
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118
119/**
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120 * Allocate or reallocate a block of memory.
121 * If *ptr is NULL and size > 0, allocate a new block. If
122 * size is zero, free the memory block pointed to by ptr.
123 * @param ptr Pointer to a pointer to a memory block already allocated
124 * with av_realloc(), or pointer to a pointer to NULL.
125 * The pointer is updated on success, or freed on failure.
126 * @param size Size in bytes for the memory block to be allocated or
127 * reallocated
128 * @return Zero on success, an AVERROR error code on failure.
129 * @warning Pointers originating from the av_malloc() family of functions must
130 * not be passed to av_reallocp(). The former can be implemented using
131 * memalign() (or other functions), and there is no guarantee that
132 * pointers from such functions can be passed to realloc() at all.
133 * The situation is undefined according to POSIX and may crash with
134 * some libc implementations.
135 */
136int av_reallocp(void *ptr, size_t size);
137
138/**
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139 * Allocate or reallocate an array.
140 * If ptr is NULL and nmemb > 0, allocate a new block. If
141 * nmemb is zero, free the memory block pointed to by ptr.
142 * @param ptr Pointer to a memory block already allocated with
b4ec7a5f 143 * av_realloc() or NULL.
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144 * @param nmemb Number of elements
145 * @param size Size of the single element
b634b36f 146 * @return Pointer to a newly-reallocated block or NULL if the block
fc962d4e 147 * cannot be reallocated or the function is used to free the memory block.
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148 * @warning Pointers originating from the av_malloc() family of functions must
149 * not be passed to av_realloc(). The former can be implemented using
150 * memalign() (or other functions), and there is no guarantee that
151 * pointers from such functions can be passed to realloc() at all.
152 * The situation is undefined according to POSIX and may crash with
153 * some libc implementations.
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154 */
155av_alloc_size(2, 3) void *av_realloc_array(void *ptr, size_t nmemb, size_t size);
156
157/**
b634b36f 158 * Allocate or reallocate an array through a pointer to a pointer.
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159 * If *ptr is NULL and nmemb > 0, allocate a new block. If
160 * nmemb is zero, free the memory block pointed to by ptr.
161 * @param ptr Pointer to a pointer to a memory block already allocated
b4ec7a5f 162 * with av_realloc(), or pointer to a pointer to NULL.
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163 * The pointer is updated on success, or freed on failure.
164 * @param nmemb Number of elements
165 * @param size Size of the single element
166 * @return Zero on success, an AVERROR error code on failure.
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167 * @warning Pointers originating from the av_malloc() family of functions must
168 * not be passed to av_realloc(). The former can be implemented using
169 * memalign() (or other functions), and there is no guarantee that
170 * pointers from such functions can be passed to realloc() at all.
171 * The situation is undefined according to POSIX and may crash with
172 * some libc implementations.
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173 */
174av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size);
175
176/**
49bd8e4b 177 * Free a memory block which has been allocated with av_malloc(z)() or
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178 * av_realloc().
179 * @param ptr Pointer to the memory block which should be freed.
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180 * @note ptr = NULL is explicitly allowed.
181 * @note It is recommended that you use av_freep() instead.
0ee97f0d 182 * @see av_freep()
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183 */
184void av_free(void *ptr);
185
0ee97f0d 186/**
49bd8e4b 187 * Allocate a block of size bytes with alignment suitable for all
0ee97f0d 188 * memory accesses (including vectors if available on the CPU) and
49bd8e4b 189 * zero all the bytes of the block.
0ee97f0d 190 * @param size Size in bytes for the memory block to be allocated.
89c9ff50 191 * @return Pointer to the allocated block, NULL if it cannot be allocated.
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192 * @see av_malloc()
193 */
490a022d 194void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
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195
196/**
b634b36f 197 * Allocate a block of size * nmemb bytes with av_mallocz().
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198 * @param nmemb Number of elements
199 * @param size Size of the single element
200 * @return Pointer to the allocated block, NULL if the block cannot
201 * be allocated.
202 * @see av_mallocz()
203 * @see av_malloc_array()
204 */
5532cf31 205av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
f3e5e6f0 206{
b284e1ff 207 if (!size || nmemb >= INT_MAX / size)
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208 return NULL;
209 return av_mallocz(nmemb * size);
210}
211
212/**
49bd8e4b 213 * Duplicate the string s.
89c9ff50 214 * @param s string to be duplicated
b634b36f 215 * @return Pointer to a newly-allocated string containing a
bf7e799c 216 * copy of s or NULL if the string cannot be allocated.
d3de3ee2 217 */
85074d3c 218char *av_strdup(const char *s) av_malloc_attrib;
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219
220/**
49bd8e4b 221 * Free a memory block which has been allocated with av_malloc(z)() or
89c9ff50 222 * av_realloc() and set the pointer pointing to it to NULL.
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223 * @param ptr Pointer to the pointer to the memory block which should
224 * be freed.
225 * @see av_free()
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226 */
227void av_freep(void *ptr);
228
757cd8d8 229/**
b634b36f 230 * deliberately overlapping memcpy implementation
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231 * @param dst destination buffer
232 * @param back how many bytes back we start (the initial size of the overlapping window)
233 * @param cnt number of bytes to copy, must be >= 0
234 *
235 * cnt > back is valid, this will copy the bytes we just copied,
236 * thus creating a repeating pattern with a period length of back.
237 */
238void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
239
240/**
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241 * @}
242 */
243
98790382 244#endif /* AVUTIL_MEM_H */