1/*
2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
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 *
11 * FFmpeg is distributed in the hope that it will be useful,
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
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file
23 * memory handling functions
24 */
25
26#ifndef AVUTIL_MEM_H
27#define AVUTIL_MEM_H
28
29#include <limits.h>
30#include <stdint.h>
31
32#include "attributes.h"
33#include "error.h"
34#include "avutil.h"
35
36/**
37 * @addtogroup lavu_mem
38 * @{
39 */
40
41
42#if defined(__INTEL_COMPILER) && __INTEL_COMPILER < 1110 || defined(__SUNPRO_C)
43    #define DECLARE_ALIGNED(n,t,v)      t __attribute__ ((aligned (n))) v
44    #define DECLARE_ASM_CONST(n,t,v)    const t __attribute__ ((aligned (n))) v
45#elif defined(__TI_COMPILER_VERSION__)
46    #define DECLARE_ALIGNED(n,t,v)                      \
47        AV_PRAGMA(DATA_ALIGN(v,n))                      \
48        t __attribute__((aligned(n))) v
49    #define DECLARE_ASM_CONST(n,t,v)                    \
50        AV_PRAGMA(DATA_ALIGN(v,n))                      \
51        static const t __attribute__((aligned(n))) v
52#elif defined(__GNUC__)
53    #define DECLARE_ALIGNED(n,t,v)      t __attribute__ ((aligned (n))) v
54    #define DECLARE_ASM_CONST(n,t,v)    static const t av_used __attribute__ ((aligned (n))) v
55#elif defined(_MSC_VER)
56    #define DECLARE_ALIGNED(n,t,v)      __declspec(align(n)) t v
57    #define DECLARE_ASM_CONST(n,t,v)    __declspec(align(n)) static const t v
58#else
59    #define DECLARE_ALIGNED(n,t,v)      t v
60    #define DECLARE_ASM_CONST(n,t,v)    static const t v
61#endif
62
63#if AV_GCC_VERSION_AT_LEAST(3,1)
64    #define av_malloc_attrib __attribute__((__malloc__))
65#else
66    #define av_malloc_attrib
67#endif
68
69#if AV_GCC_VERSION_AT_LEAST(4,3)
70    #define av_alloc_size(...) __attribute__((alloc_size(__VA_ARGS__)))
71#else
72    #define av_alloc_size(...)
73#endif
74
75/**
76 * Allocate a block of size bytes with alignment suitable for all
77 * memory accesses (including vectors if available on the CPU).
78 * @param size Size in bytes for the memory block to be allocated.
79 * @return Pointer to the allocated block, NULL if the block cannot
80 * be allocated.
81 * @see av_mallocz()
82 */
83void *av_malloc(size_t size) av_malloc_attrib av_alloc_size(1);
84
85/**
86 * Allocate a block of size * nmemb bytes with av_malloc().
87 * @param nmemb Number of elements
88 * @param size Size of the single element
89 * @return Pointer to the allocated block, NULL if the block cannot
90 * be allocated.
91 * @see av_malloc()
92 */
93av_alloc_size(1, 2) static inline void *av_malloc_array(size_t nmemb, size_t size)
94{
95    if (!size || nmemb >= INT_MAX / size)
96        return NULL;
97    return av_malloc(nmemb * size);
98}
99
100/**
101 * Allocate or reallocate a block of memory.
102 * If ptr is NULL and size > 0, allocate a new block. If
103 * size is zero, free the memory block pointed to by ptr.
104 * @param ptr Pointer to a memory block already allocated with
105 * av_realloc() or NULL.
106 * @param size Size in bytes of the memory block to be allocated or
107 * reallocated.
108 * @return Pointer to a newly-reallocated block or NULL if the block
109 * cannot be reallocated or the function is used to free the memory block.
110 * @warning Pointers originating from the av_malloc() family of functions must
111 *          not be passed to av_realloc(). The former can be implemented using
112 *          memalign() (or other functions), and there is no guarantee that
113 *          pointers from such functions can be passed to realloc() at all.
114 *          The situation is undefined according to POSIX and may crash with
115 *          some libc implementations.
116 * @see av_fast_realloc()
117 */
118void *av_realloc(void *ptr, size_t size) av_alloc_size(2);
119
120/**
121 * Allocate or reallocate a block of memory.
122 * This function does the same thing as av_realloc, except:
123 * - It takes two arguments and checks the result of the multiplication for
124 *   integer overflow.
125 * - It frees the input block in case of failure, thus avoiding the memory
126 *   leak with the classic "buf = realloc(buf); if (!buf) return -1;".
127 */
128void *av_realloc_f(void *ptr, size_t nelem, size_t elsize);
129
130/**
131 * Allocate or reallocate a block of memory.
132 * If *ptr is NULL and size > 0, allocate a new block. If
133 * size is zero, free the memory block pointed to by ptr.
134 * @param   ptr Pointer to a pointer to a memory block already allocated
135 *          with av_realloc(), or pointer to a pointer to NULL.
136 *          The pointer is updated on success, or freed on failure.
137 * @param   size Size in bytes for the memory block to be allocated or
138 *          reallocated
139 * @return  Zero on success, an AVERROR error code on failure.
140 * @warning Pointers originating from the av_malloc() family of functions must
141 *          not be passed to av_reallocp(). The former can be implemented using
142 *          memalign() (or other functions), and there is no guarantee that
143 *          pointers from such functions can be passed to realloc() at all.
144 *          The situation is undefined according to POSIX and may crash with
145 *          some libc implementations.
146 */
147int av_reallocp(void *ptr, size_t size);
148
149/**
150 * Allocate or reallocate an array.
151 * If ptr is NULL and nmemb > 0, allocate a new block. If
152 * nmemb is zero, free the memory block pointed to by ptr.
153 * @param ptr Pointer to a memory block already allocated with
154 * av_realloc() or NULL.
155 * @param nmemb Number of elements
156 * @param size Size of the single element
157 * @return Pointer to a newly-reallocated block or NULL if the block
158 * cannot be reallocated or the function is used to free the memory block.
159 * @warning Pointers originating from the av_malloc() family of functions must
160 *          not be passed to av_realloc(). The former can be implemented using
161 *          memalign() (or other functions), and there is no guarantee that
162 *          pointers from such functions can be passed to realloc() at all.
163 *          The situation is undefined according to POSIX and may crash with
164 *          some libc implementations.
165 */
166av_alloc_size(2, 3) void *av_realloc_array(void *ptr, size_t nmemb, size_t size);
167
168/**
169 * Allocate or reallocate an array through a pointer to a pointer.
170 * If *ptr is NULL and nmemb > 0, allocate a new block. If
171 * nmemb is zero, free the memory block pointed to by ptr.
172 * @param ptr Pointer to a pointer to a memory block already allocated
173 * with av_realloc(), or pointer to a pointer to NULL.
174 * The pointer is updated on success, or freed on failure.
175 * @param nmemb Number of elements
176 * @param size Size of the single element
177 * @return Zero on success, an AVERROR error code on failure.
178 * @warning Pointers originating from the av_malloc() family of functions must
179 *          not be passed to av_realloc(). The former can be implemented using
180 *          memalign() (or other functions), and there is no guarantee that
181 *          pointers from such functions can be passed to realloc() at all.
182 *          The situation is undefined according to POSIX and may crash with
183 *          some libc implementations.
184 */
185av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size);
186
187/**
188 * Free a memory block which has been allocated with av_malloc(z)() or
189 * av_realloc().
190 * @param ptr Pointer to the memory block which should be freed.
191 * @note ptr = NULL is explicitly allowed.
192 * @note It is recommended that you use av_freep() instead.
193 * @see av_freep()
194 */
195void av_free(void *ptr);
196
197/**
198 * Allocate a block of size bytes with alignment suitable for all
199 * memory accesses (including vectors if available on the CPU) and
200 * zero all the bytes of the block.
201 * @param size Size in bytes for the memory block to be allocated.
202 * @return Pointer to the allocated block, NULL if it cannot be allocated.
203 * @see av_malloc()
204 */
205void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
206
207/**
208 * Allocate a block of nmemb * size bytes with alignment suitable for all
209 * memory accesses (including vectors if available on the CPU) and
210 * zero all the bytes of the block.
211 * The allocation will fail if nmemb * size is greater than or equal
212 * to INT_MAX.
213 * @param nmemb
214 * @param size
215 * @return Pointer to the allocated block, NULL if it cannot be allocated.
216 */
217void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib;
218
219/**
220 * Allocate a block of size * nmemb bytes with av_mallocz().
221 * @param nmemb Number of elements
222 * @param size Size of the single element
223 * @return Pointer to the allocated block, NULL if the block cannot
224 * be allocated.
225 * @see av_mallocz()
226 * @see av_malloc_array()
227 */
228av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
229{
230    if (!size || nmemb >= INT_MAX / size)
231        return NULL;
232    return av_mallocz(nmemb * size);
233}
234
235/**
236 * Duplicate the string s.
237 * @param s string to be duplicated
238 * @return Pointer to a newly-allocated string containing a
239 * copy of s or NULL if the string cannot be allocated.
240 */
241char *av_strdup(const char *s) av_malloc_attrib;
242
243/**
244 * Duplicate the buffer p.
245 * @param p buffer to be duplicated
246 * @return Pointer to a newly allocated buffer containing a
247 * copy of p or NULL if the buffer cannot be allocated.
248 */
249void *av_memdup(const void *p, size_t size);
250
251/**
252 * Free a memory block which has been allocated with av_malloc(z)() or
253 * av_realloc() and set the pointer pointing to it to NULL.
254 * @param ptr Pointer to the pointer to the memory block which should
255 * be freed.
256 * @see av_free()
257 */
258void av_freep(void *ptr);
259
260/**
261 * Add an element to a dynamic array.
262 *
263 * The array to grow is supposed to be an array of pointers to
264 * structures, and the element to add must be a pointer to an already
265 * allocated structure.
266 *
267 * The array is reallocated when its size reaches powers of 2.
268 * Therefore, the amortized cost of adding an element is constant.
269 *
270 * In case of success, the pointer to the array is updated in order to
271 * point to the new grown array, and the number pointed to by nb_ptr
272 * is incremented.
273 * In case of failure, the array is freed, *tab_ptr is set to NULL and
274 * *nb_ptr is set to 0.
275 *
276 * @param tab_ptr pointer to the array to grow
277 * @param nb_ptr  pointer to the number of elements in the array
278 * @param elem    element to add
279 * @see av_dynarray_add_nofree(), av_dynarray2_add()
280 */
281void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
282
283/**
284 * Add an element to a dynamic array.
285 *
286 * Function has the same functionality as av_dynarray_add(),
287 * but it doesn't free memory on fails. It returns error code
288 * instead and leave current buffer untouched.
289 *
290 * @param tab_ptr pointer to the array to grow
291 * @param nb_ptr  pointer to the number of elements in the array
292 * @param elem    element to add
293 * @return >=0 on success, negative otherwise.
294 * @see av_dynarray_add(), av_dynarray2_add()
295 */
296int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem);
297
298/**
299 * Add an element of size elem_size to a dynamic array.
300 *
301 * The array is reallocated when its number of elements reaches powers of 2.
302 * Therefore, the amortized cost of adding an element is constant.
303 *
304 * In case of success, the pointer to the array is updated in order to
305 * point to the new grown array, and the number pointed to by nb_ptr
306 * is incremented.
307 * In case of failure, the array is freed, *tab_ptr is set to NULL and
308 * *nb_ptr is set to 0.
309 *
310 * @param tab_ptr   pointer to the array to grow
311 * @param nb_ptr    pointer to the number of elements in the array
312 * @param elem_size size in bytes of the elements in the array
313 * @param elem_data pointer to the data of the element to add. If NULL, the space of
314 *                  the new added element is not filled.
315 * @return          pointer to the data of the element to copy in the new allocated space.
316 *                  If NULL, the new allocated space is left uninitialized."
317 * @see av_dynarray_add(), av_dynarray_add_nofree()
318 */
319void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
320                       const uint8_t *elem_data);
321
322/**
323 * Multiply two size_t values checking for overflow.
324 * @return  0 if success, AVERROR(EINVAL) if overflow.
325 */
326static inline int av_size_mult(size_t a, size_t b, size_t *r)
327{
328    size_t t = a * b;
329    /* Hack inspired from glibc: only try the division if nelem and elsize
330     * are both greater than sqrt(SIZE_MAX). */
331    if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
332        return AVERROR(EINVAL);
333    *r = t;
334    return 0;
335}
336
337/**
338 * Set the maximum size that may me allocated in one block.
339 */
340void av_max_alloc(size_t max);
341
342/**
343 * deliberately overlapping memcpy implementation
344 * @param dst destination buffer
345 * @param back how many bytes back we start (the initial size of the overlapping window), must be > 0
346 * @param cnt number of bytes to copy, must be >= 0
347 *
348 * cnt > back is valid, this will copy the bytes we just copied,
349 * thus creating a repeating pattern with a period length of back.
350 */
351void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
352
353/**
354 * Reallocate the given block if it is not large enough, otherwise do nothing.
355 *
356 * @see av_realloc
357 */
358void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size);
359
360/**
361 * Allocate a buffer, reusing the given one if large enough.
362 *
363 * Contrary to av_fast_realloc the current buffer contents might not be
364 * preserved and on error the old buffer is freed, thus no special
365 * handling to avoid memleaks is necessary.
366 *
367 * @param ptr pointer to pointer to already allocated buffer, overwritten with pointer to new buffer
368 * @param size size of the buffer *ptr points to
369 * @param min_size minimum size of *ptr buffer after returning, *ptr will be NULL and
370 *                 *size 0 if an error occurred.
371 */
372void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size);
373
374/**
375 * @}
376 */
377
378#endif /* AVUTIL_MEM_H */
379