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mem.h
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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  */
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  */
93 av_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  */
118 void *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  */
128 void *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  */
148 int av_reallocp(void *ptr, size_t size);
149 
150 /**
151  * Allocate or reallocate an array.
152  * If ptr is NULL and nmemb > 0, allocate a new block. If
153  * nmemb is zero, free the memory block pointed to by ptr.
154  * @param ptr Pointer to a memory block already allocated with
155  * av_realloc() or NULL.
156  * @param nmemb Number of elements
157  * @param size Size of the single element
158  * @return Pointer to a newly-reallocated block or NULL if the block
159  * cannot be reallocated or the function is used to free the memory block.
160  * @warning Pointers originating from the av_malloc() family of functions must
161  * not be passed to av_realloc(). The former can be implemented using
162  * memalign() (or other functions), and there is no guarantee that
163  * pointers from such functions can be passed to realloc() at all.
164  * The situation is undefined according to POSIX and may crash with
165  * some libc implementations.
166  */
167 av_alloc_size(2, 3) void *av_realloc_array(void *ptr, size_t nmemb, size_t size);
168 
169 /**
170  * Allocate or reallocate an array through a pointer to a pointer.
171  * If *ptr is NULL and nmemb > 0, allocate a new block. If
172  * nmemb is zero, free the memory block pointed to by ptr.
173  * @param ptr Pointer to a pointer to a memory block already allocated
174  * with av_realloc(), or pointer to a pointer to NULL.
175  * The pointer is updated on success, or freed on failure.
176  * @param nmemb Number of elements
177  * @param size Size of the single element
178  * @return Zero on success, an AVERROR error code on failure.
179  * @warning Pointers originating from the av_malloc() family of functions must
180  * not be passed to av_realloc(). The former can be implemented using
181  * memalign() (or other functions), and there is no guarantee that
182  * pointers from such functions can be passed to realloc() at all.
183  * The situation is undefined according to POSIX and may crash with
184  * some libc implementations.
185  */
186 av_alloc_size(2, 3) int av_reallocp_array(void *ptr, size_t nmemb, size_t size);
187 
188 /**
189  * Free a memory block which has been allocated with av_malloc(z)() or
190  * av_realloc().
191  * @param ptr Pointer to the memory block which should be freed.
192  * @note ptr = NULL is explicitly allowed.
193  * @note It is recommended that you use av_freep() instead.
194  * @see av_freep()
195  */
196 void av_free(void *ptr);
197 
198 /**
199  * Allocate a block of size bytes with alignment suitable for all
200  * memory accesses (including vectors if available on the CPU) and
201  * zero all the bytes of the block.
202  * @param size Size in bytes for the memory block to be allocated.
203  * @return Pointer to the allocated block, NULL if it cannot be allocated.
204  * @see av_malloc()
205  */
206 void *av_mallocz(size_t size) av_malloc_attrib av_alloc_size(1);
207 
208 /**
209  * Allocate a block of nmemb * size bytes with alignment suitable for all
210  * memory accesses (including vectors if available on the CPU) and
211  * zero all the bytes of the block.
212  * The allocation will fail if nmemb * size is greater than or equal
213  * to INT_MAX.
214  * @param nmemb
215  * @param size
216  * @return Pointer to the allocated block, NULL if it cannot be allocated.
217  */
218 void *av_calloc(size_t nmemb, size_t size) av_malloc_attrib;
219 
220 /**
221  * Allocate a block of size * nmemb bytes with av_mallocz().
222  * @param nmemb Number of elements
223  * @param size Size of the single element
224  * @return Pointer to the allocated block, NULL if the block cannot
225  * be allocated.
226  * @see av_mallocz()
227  * @see av_malloc_array()
228  */
229 av_alloc_size(1, 2) static inline void *av_mallocz_array(size_t nmemb, size_t size)
230 {
231  if (!size || nmemb >= INT_MAX / size)
232  return NULL;
233  return av_mallocz(nmemb * size);
234 }
235 
236 /**
237  * Duplicate the string s.
238  * @param s string to be duplicated
239  * @return Pointer to a newly-allocated string containing a
240  * copy of s or NULL if the string cannot be allocated.
241  */
242 char *av_strdup(const char *s) av_malloc_attrib;
243 
244 /**
245  * Duplicate a substring of the string s.
246  * @param s string to be duplicated
247  * @param len the maximum length of the resulting string (not counting the
248  * terminating byte).
249  * @return Pointer to a newly-allocated string containing a
250  * copy of s or NULL if the string cannot be allocated.
251  */
252 char *av_strndup(const char *s, size_t len) av_malloc_attrib;
253 
254 /**
255  * Duplicate the buffer p.
256  * @param p buffer to be duplicated
257  * @return Pointer to a newly allocated buffer containing a
258  * copy of p or NULL if the buffer cannot be allocated.
259  */
260 void *av_memdup(const void *p, size_t size);
261 
262 /**
263  * Free a memory block which has been allocated with av_malloc(z)() or
264  * av_realloc() and set the pointer pointing to it to NULL.
265  * @param ptr Pointer to the pointer to the memory block which should
266  * be freed.
267  * @note passing a pointer to a NULL pointer is safe and leads to no action.
268  * @see av_free()
269  */
270 void av_freep(void *ptr);
271 
272 /**
273  * Add an element to a dynamic array.
274  *
275  * The array to grow is supposed to be an array of pointers to
276  * structures, and the element to add must be a pointer to an already
277  * allocated structure.
278  *
279  * The array is reallocated when its size reaches powers of 2.
280  * Therefore, the amortized cost of adding an element is constant.
281  *
282  * In case of success, the pointer to the array is updated in order to
283  * point to the new grown array, and the number pointed to by nb_ptr
284  * is incremented.
285  * In case of failure, the array is freed, *tab_ptr is set to NULL and
286  * *nb_ptr is set to 0.
287  *
288  * @param tab_ptr pointer to the array to grow
289  * @param nb_ptr pointer to the number of elements in the array
290  * @param elem element to add
291  * @see av_dynarray_add_nofree(), av_dynarray2_add()
292  */
293 void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem);
294 
295 /**
296  * Add an element to a dynamic array.
297  *
298  * Function has the same functionality as av_dynarray_add(),
299  * but it doesn't free memory on fails. It returns error code
300  * instead and leave current buffer untouched.
301  *
302  * @param tab_ptr pointer to the array to grow
303  * @param nb_ptr pointer to the number of elements in the array
304  * @param elem element to add
305  * @return >=0 on success, negative otherwise.
306  * @see av_dynarray_add(), av_dynarray2_add()
307  */
309 int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem);
310 
311 /**
312  * Add an element of size elem_size to a dynamic array.
313  *
314  * The array is reallocated when its number of elements reaches powers of 2.
315  * Therefore, the amortized cost of adding an element is constant.
316  *
317  * In case of success, the pointer to the array is updated in order to
318  * point to the new grown array, and the number pointed to by nb_ptr
319  * is incremented.
320  * In case of failure, the array is freed, *tab_ptr is set to NULL and
321  * *nb_ptr is set to 0.
322  *
323  * @param tab_ptr pointer to the array to grow
324  * @param nb_ptr pointer to the number of elements in the array
325  * @param elem_size size in bytes of the elements in the array
326  * @param elem_data pointer to the data of the element to add. If NULL, the space of
327  * the new added element is not filled.
328  * @return pointer to the data of the element to copy in the new allocated space.
329  * If NULL, the new allocated space is left uninitialized."
330  * @see av_dynarray_add(), av_dynarray_add_nofree()
331  */
332 void *av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size,
333  const uint8_t *elem_data);
334 
335 /**
336  * Multiply two size_t values checking for overflow.
337  * @return 0 if success, AVERROR(EINVAL) if overflow.
338  */
339 static inline int av_size_mult(size_t a, size_t b, size_t *r)
340 {
341  size_t t = a * b;
342  /* Hack inspired from glibc: don't try the division if nelem and elsize
343  * are both less than sqrt(SIZE_MAX). */
344  if ((a | b) >= ((size_t)1 << (sizeof(size_t) * 4)) && a && t / a != b)
345  return AVERROR(EINVAL);
346  *r = t;
347  return 0;
348 }
349 
350 /**
351  * Set the maximum size that may me allocated in one block.
352  */
353 void av_max_alloc(size_t max);
354 
355 /**
356  * deliberately overlapping memcpy implementation
357  * @param dst destination buffer
358  * @param back how many bytes back we start (the initial size of the overlapping window), must be > 0
359  * @param cnt number of bytes to copy, must be >= 0
360  *
361  * cnt > back is valid, this will copy the bytes we just copied,
362  * thus creating a repeating pattern with a period length of back.
363  */
364 void av_memcpy_backptr(uint8_t *dst, int back, int cnt);
365 
366 /**
367  * Reallocate the given block if it is not large enough, otherwise do nothing.
368  *
369  * @see av_realloc
370  */
371 void *av_fast_realloc(void *ptr, unsigned int *size, size_t min_size);
372 
373 /**
374  * Allocate a buffer, reusing the given one if large enough.
375  *
376  * Contrary to av_fast_realloc the current buffer contents might not be
377  * preserved and on error the old buffer is freed, thus no special
378  * handling to avoid memleaks is necessary.
379  *
380  * @param ptr pointer to pointer to already allocated buffer, overwritten with pointer to new buffer
381  * @param size size of the buffer *ptr points to
382  * @param min_size minimum size of *ptr buffer after returning, *ptr will be NULL and
383  * *size 0 if an error occurred.
384  */
385 void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size);
386 
387 /**
388  * Allocate a buffer, reusing the given one if large enough.
389  *
390  * All newly allocated space is initially cleared
391  * Contrary to av_fast_realloc the current buffer contents might not be
392  * preserved and on error the old buffer is freed, thus no special
393  * handling to avoid memleaks is necessary.
394  *
395  * @param ptr pointer to pointer to already allocated buffer, overwritten with pointer to new buffer
396  * @param size size of the buffer *ptr points to
397  * @param min_size minimum size of *ptr buffer after returning, *ptr will be NULL and
398  * *size 0 if an error occurred.
399  */
400 void av_fast_mallocz(void *ptr, unsigned int *size, size_t min_size);
401 
402 /**
403  * @}
404  */
405 
406 #endif /* AVUTIL_MEM_H */
#define NULL
Definition: coverity.c:32
void * av_malloc(size_t size) av_malloc_attrib 1(1)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:77
const char * s
Definition: avisynth_c.h:631
void * av_realloc_f(void *ptr, size_t nelem, size_t elsize)
Allocate or reallocate a block of memory.
Definition: mem.c:172
const char * b
Definition: vf_curves.c:113
void * av_dynarray2_add(void **tab_ptr, int *nb_ptr, size_t elem_size, const uint8_t *elem_data)
Add an element of size elem_size to a dynamic array.
Definition: mem.c:338
external API header
void av_max_alloc(size_t max)
Set the maximum size that may me allocated in one block.
Definition: mem.c:73
Macro definitions for various function/variable attributes.
void av_freep(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc() and set the pointer ...
Definition: mem.c:243
uint8_t
void av_fast_mallocz(void *ptr, unsigned int *size, size_t min_size)
Allocate a buffer, reusing the given one if large enough.
Definition: mem.c:504
#define av_alloc_size(...)
Definition: mem.h:70
char * av_strndup(const char *s, size_t len) av_malloc_attrib
Duplicate a substring of the string s.
Definition: mem.c:279
ptrdiff_t size
Definition: opengl_enc.c:101
int av_reallocp_array(void *ptr, size_t nmemb, size_t size)
Definition: mem.c:215
void av_free(void *ptr)
Free a memory block which has been allocated with av_malloc(z)() or av_realloc(). ...
Definition: mem.c:228
error code definitions
void * av_fast_realloc(void *ptr, unsigned int *size, size_t min_size)
Reallocate the given block if it is not large enough, otherwise do nothing.
Definition: mem.c:480
av_warn_unused_result int av_dynarray_add_nofree(void *tab_ptr, int *nb_ptr, void *elem)
Add an element to a dynamic array.
Definition: mem.c:310
#define AVERROR(e)
Definition: error.h:43
const char * r
Definition: vf_curves.c:111
void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
Add an element to a dynamic array.
Definition: mem.c:324
#define av_malloc_attrib
Definition: mem.h:64
typedef void(APIENTRY *FF_PFNGLACTIVETEXTUREPROC)(GLenum texture)
static int av_size_mult(size_t a, size_t b, size_t *r)
Multiply two size_t values checking for overflow.
Definition: mem.h:339
void * av_memdup(const void *p, size_t size)
Duplicate the buffer p.
Definition: mem.c:299
char * av_strdup(const char *s) av_malloc_attrib
Duplicate the string s.
Definition: mem.c:267
void * av_calloc(size_t nmemb, size_t size) av_malloc_attrib
Allocate a block of nmemb * size bytes with alignment suitable for all memory accesses (including vec...
Definition: mem.c:260
static void * av_malloc_array(size_t nmemb, size_t size)
Definition: mem.h:93
#define av_warn_unused_result
Definition: attributes.h:56
void av_fast_malloc(void *ptr, unsigned int *size, size_t min_size)
Allocate a buffer, reusing the given one if large enough.
Definition: mem.c:499
void * av_realloc(void *ptr, size_t size) 1(2)
Allocate or reallocate a block of memory.
Definition: mem.c:145
av_warn_unused_result int av_reallocp(void *ptr, size_t size)
Allocate or reallocate a block of memory.
Definition: mem.c:187
void * av_realloc_array(void *ptr, size_t nmemb, size_t size)
Definition: mem.c:208
int len
static void * av_mallocz_array(size_t nmemb, size_t size)
Definition: mem.h:229
void av_memcpy_backptr(uint8_t *dst, int back, int cnt)
deliberately overlapping memcpy implementation
Definition: mem.c:430
void * av_mallocz(size_t size) av_malloc_attrib 1(1)
Allocate a block of size bytes with alignment suitable for all memory accesses (including vectors if ...
Definition: mem.c:252