1 /*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19 /**
20 * @file
21 * a very simple circular buffer FIFO implementation
22 */
23
24 #ifndef AVUTIL_FIFO_H
25 #define AVUTIL_FIFO_H
26
27 #include <stddef.h>
28 #include <stdint.h>
29
30 #include "attributes.h"
31 #include "version.h"
32
33 typedef struct AVFifo AVFifo;
34
35 /**
36 * Callback for writing or reading from a FIFO, passed to (and invoked from) the
37 * av_fifo_*_cb() functions. It may be invoked multiple times from a single
38 * av_fifo_*_cb() call and may process less data than the maximum size indicated
39 * by nb_elems.
40 *
41 * @param opaque the opaque pointer provided to the av_fifo_*_cb() function
42 * @param buf the buffer for reading or writing the data, depending on which
43 * av_fifo_*_cb function is called
44 * @param nb_elems On entry contains the maximum number of elements that can be
45 * read from / written into buf. On success, the callback should
46 * update it to contain the number of elements actually written.
47 *
48 * @return 0 on success, a negative error code on failure (will be returned from
49 * the invoking av_fifo_*_cb() function)
50 */
51 typedef int AVFifoCB(void *opaque, void *buf, size_t *nb_elems);
52
53 /**
54 * Automatically resize the FIFO on writes, so that the data fits. This
55 * automatic resizing happens up to a limit that can be modified with
56 * av_fifo_auto_grow_limit().
57 */
58 #define AV_FIFO_FLAG_AUTO_GROW (1 << 0)
59
60 /**
61 * Allocate and initialize an AVFifo with a given element size.
62 *
63 * @param elems initial number of elements that can be stored in the FIFO
64 * @param elem_size Size in bytes of a single element. Further operations on
65 * the returned FIFO will implicitly use this element size.
66 * @param flags a combination of AV_FIFO_FLAG_*
67 *
68 * @return newly-allocated AVFifo on success, a negative error code on failure
69 */
70 AVFifo *av_fifo_alloc2(size_t elems, size_t elem_size,
71 unsigned int flags);
72
73 /**
74 * @return Element size for FIFO operations. This element size is set at
75 * FIFO allocation and remains constant during its lifetime
76 */
77 size_t av_fifo_elem_size(const AVFifo *f);
78
79 /**
80 * Set the maximum size (in elements) to which the FIFO can be resized
81 * automatically. Has no effect unless AV_FIFO_FLAG_AUTO_GROW is used.
82 */
83 void av_fifo_auto_grow_limit(AVFifo *f, size_t max_elems);
84
85 /**
86 * @return number of elements available for reading from the given FIFO.
87 */
88 size_t av_fifo_can_read(const AVFifo *f);
89
90 /**
91 * @return number of elements that can be written into the given FIFO.
92 */
93 size_t av_fifo_can_write(const AVFifo *f);
94
95 /**
96 * Enlarge an AVFifo.
97 *
98 * On success, the FIFO will be large enough to hold exactly
99 * inc + av_fifo_can_read() + av_fifo_can_write()
100 * elements. In case of failure, the old FIFO is kept unchanged.
101 *
102 * @param f AVFifo to resize
103 * @param inc number of elements to allocate for, in addition to the current
104 * allocated size
105 * @return a non-negative number on success, a negative error code on failure
106 */
107 int av_fifo_grow2(AVFifo *f, size_t inc);
108
109 /**
110 * Write data into a FIFO.
111 *
112 * In case nb_elems > av_fifo_can_write(f), nothing is written and an error
113 * is returned.
114 *
115 * @param f the FIFO buffer
116 * @param buf Data to be written. nb_elems * av_fifo_elem_size(f) bytes will be
117 * read from buf on success.
118 * @param nb_elems number of elements to write into FIFO
119 *
120 * @return a non-negative number on success, a negative error code on failure
121 */
122 int av_fifo_write(AVFifo *f, const void *buf, size_t nb_elems);
123
124 /**
125 * Write data from a user-provided callback into a FIFO.
126 *
127 * @param f the FIFO buffer
128 * @param read_cb Callback supplying the data to the FIFO. May be called
129 * multiple times.
130 * @param opaque opaque user data to be provided to read_cb
131 * @param nb_elems Should point to the maximum number of elements that can be
132 * written. Will be updated to contain the number of elements
133 * actually written.
134 *
135 * @return non-negative number on success, a negative error code on failure
136 */
137 int av_fifo_write_from_cb(AVFifo *f, AVFifoCB read_cb,
138 void *opaque, size_t *nb_elems);
139
140 /**
141 * Read data from a FIFO.
142 *
143 * In case nb_elems > av_fifo_can_read(f), nothing is read and an error
144 * is returned.
145 *
146 * @param f the FIFO buffer
147 * @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes
148 * will be written into buf on success.
149 * @param nb_elems number of elements to read from FIFO
150 *
151 * @return a non-negative number on success, a negative error code on failure
152 */
153 int av_fifo_read(AVFifo *f, void *buf, size_t nb_elems);
154
155 /**
156 * Feed data from a FIFO into a user-provided callback.
157 *
158 * @param f the FIFO buffer
159 * @param write_cb Callback the data will be supplied to. May be called
160 * multiple times.
161 * @param opaque opaque user data to be provided to write_cb
162 * @param nb_elems Should point to the maximum number of elements that can be
163 * read. Will be updated to contain the total number of elements
164 * actually sent to the callback.
165 *
166 * @return non-negative number on success, a negative error code on failure
167 */
168 int av_fifo_read_to_cb(AVFifo *f, AVFifoCB write_cb,
169 void *opaque, size_t *nb_elems);
170
171 /**
172 * Read data from a FIFO without modifying FIFO state.
173 *
174 * Returns an error if an attempt is made to peek to nonexistent elements
175 * (i.e. if offset + nb_elems is larger than av_fifo_can_read(f)).
176 *
177 * @param f the FIFO buffer
178 * @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes
179 * will be written into buf.
180 * @param nb_elems number of elements to read from FIFO
181 * @param offset number of initial elements to skip.
182 *
183 * @return a non-negative number on success, a negative error code on failure
184 */
185 int av_fifo_peek(AVFifo *f, void *buf, size_t nb_elems, size_t offset);
186
187 /**
188 * Feed data from a FIFO into a user-provided callback.
189 *
190 * @param f the FIFO buffer
191 * @param write_cb Callback the data will be supplied to. May be called
192 * multiple times.
193 * @param opaque opaque user data to be provided to write_cb
194 * @param nb_elems Should point to the maximum number of elements that can be
195 * read. Will be updated to contain the total number of elements
196 * actually sent to the callback.
197 * @param offset number of initial elements to skip; offset + *nb_elems must not
198 * be larger than av_fifo_can_read(f).
199 *
200 * @return a non-negative number on success, a negative error code on failure
201 */
202 int av_fifo_peek_to_cb(AVFifo *f, AVFifoCB write_cb, void *opaque,
203 size_t *nb_elems, size_t offset);
204
205 /**
206 * Discard the specified amount of data from an AVFifo.
207 * @param size number of elements to discard, MUST NOT be larger than
208 * av_fifo_can_read(f)
209 */
210 void av_fifo_drain2(AVFifo *f, size_t size);
211
212 /*
213 * Empty the AVFifo.
214 * @param f AVFifo to reset
215 */
216 void av_fifo_reset2(AVFifo *f);
217
218 /**
219 * Free an AVFifo and reset pointer to NULL.
220 * @param f Pointer to an AVFifo to free. *f == NULL is allowed.
221 */
222 void av_fifo_freep2(AVFifo **f);
223
224
225 #if FF_API_FIFO_OLD_API
226 typedef struct AVFifoBuffer {
227 uint8_t *buffer;
228 uint8_t *rptr, *wptr, *end;
229 uint32_t rndx, wndx;
230 } AVFifoBuffer;
231
232 /**
233 * Initialize an AVFifoBuffer.
234 * @param size of FIFO
235 * @return AVFifoBuffer or NULL in case of memory allocation failure
236 * @deprecated use av_fifo_alloc2()
237 */
238 attribute_deprecated
239 AVFifoBuffer *av_fifo_alloc(unsigned int size);
240
241 /**
242 * Initialize an AVFifoBuffer.
243 * @param nmemb number of elements
244 * @param size size of the single element
245 * @return AVFifoBuffer or NULL in case of memory allocation failure
246 * @deprecated use av_fifo_alloc2()
247 */
248 attribute_deprecated
249 AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size);
250
251 /**
252 * Free an AVFifoBuffer.
253 * @param f AVFifoBuffer to free
254 * @deprecated use the AVFifo API with av_fifo_freep2()
255 */
256 attribute_deprecated
257 void av_fifo_free(AVFifoBuffer *f);
258
259 /**
260 * Free an AVFifoBuffer and reset pointer to NULL.
261 * @param f AVFifoBuffer to free
262 * @deprecated use the AVFifo API with av_fifo_freep2()
263 */
264 attribute_deprecated
265 void av_fifo_freep(AVFifoBuffer **f);
266
267 /**
268 * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
269 * @param f AVFifoBuffer to reset
270 * @deprecated use av_fifo_reset2() with the new AVFifo-API
271 */
272 attribute_deprecated
273 void av_fifo_reset(AVFifoBuffer *f);
274
275 /**
276 * Return the amount of data in bytes in the AVFifoBuffer, that is the
277 * amount of data you can read from it.
278 * @param f AVFifoBuffer to read from
279 * @return size
280 * @deprecated use av_fifo_can_read() with the new AVFifo-API
281 */
282 attribute_deprecated
283 int av_fifo_size(const AVFifoBuffer *f);
284
285 /**
286 * Return the amount of space in bytes in the AVFifoBuffer, that is the
287 * amount of data you can write into it.
288 * @param f AVFifoBuffer to write into
289 * @return size
290 * @deprecated use av_fifo_can_write() with the new AVFifo-API
291 */
292 attribute_deprecated
293 int av_fifo_space(const AVFifoBuffer *f);
294
295 /**
296 * Feed data at specific position from an AVFifoBuffer to a user-supplied callback.
297 * Similar as av_fifo_gereric_read but without discarding data.
298 * @param f AVFifoBuffer to read from
299 * @param offset offset from current read position
300 * @param buf_size number of bytes to read
301 * @param func generic read function
302 * @param dest data destination
303 *
304 * @return a non-negative number on success, a negative error code on failure
305 *
306 * @deprecated use the new AVFifo-API with av_fifo_peek() when func == NULL,
307 * av_fifo_peek_to_cb() otherwise
308 */
309 attribute_deprecated
310 int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void (*func)(void*, void*, int));
311
312 /**
313 * Feed data from an AVFifoBuffer to a user-supplied callback.
314 * Similar as av_fifo_gereric_read but without discarding data.
315 * @param f AVFifoBuffer to read from
316 * @param buf_size number of bytes to read
317 * @param func generic read function
318 * @param dest data destination
319 *
320 * @return a non-negative number on success, a negative error code on failure
321 *
322 * @deprecated use the new AVFifo-API with av_fifo_peek() when func == NULL,
323 * av_fifo_peek_to_cb() otherwise
324 */
325 attribute_deprecated
326 int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
327
328 /**
329 * Feed data from an AVFifoBuffer to a user-supplied callback.
330 * @param f AVFifoBuffer to read from
331 * @param buf_size number of bytes to read
332 * @param func generic read function
333 * @param dest data destination
334 *
335 * @return a non-negative number on success, a negative error code on failure
336 *
337 * @deprecated use the new AVFifo-API with av_fifo_read() when func == NULL,
338 * av_fifo_read_to_cb() otherwise
339 */
340 attribute_deprecated
341 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
342
343 /**
344 * Feed data from a user-supplied callback to an AVFifoBuffer.
345 * @param f AVFifoBuffer to write to
346 * @param src data source; non-const since it may be used as a
347 * modifiable context by the function defined in func
348 * @param size number of bytes to write
349 * @param func generic write function; the first parameter is src,
350 * the second is dest_buf, the third is dest_buf_size.
351 * func must return the number of bytes written to dest_buf, or <= 0 to
352 * indicate no more data available to write.
353 * If func is NULL, src is interpreted as a simple byte array for source data.
354 * @return the number of bytes written to the FIFO or a negative error code on failure
355 *
356 * @deprecated use the new AVFifo-API with av_fifo_write() when func == NULL,
357 * av_fifo_write_from_cb() otherwise
358 */
359 attribute_deprecated
360 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
361
362 /**
363 * Resize an AVFifoBuffer.
364 * In case of reallocation failure, the old FIFO is kept unchanged.
365 *
366 * @param f AVFifoBuffer to resize
367 * @param size new AVFifoBuffer size in bytes
368 * @return <0 for failure, >=0 otherwise
369 *
370 * @deprecated use the new AVFifo-API with av_fifo_grow2() to increase FIFO size,
371 * decreasing FIFO size is not supported
372 */
373 attribute_deprecated
374 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
375
376 /**
377 * Enlarge an AVFifoBuffer.
378 * In case of reallocation failure, the old FIFO is kept unchanged.
379 * The new fifo size may be larger than the requested size.
380 *
381 * @param f AVFifoBuffer to resize
382 * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
383 * @return <0 for failure, >=0 otherwise
384 *
385 * @deprecated use the new AVFifo-API with av_fifo_grow2(); note that unlike
386 * this function it adds to the allocated size, rather than to the used size
387 */
388 attribute_deprecated
389 int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);
390
391 /**
392 * Read and discard the specified amount of data from an AVFifoBuffer.
393 * @param f AVFifoBuffer to read from
394 * @param size amount of data to read in bytes
395 *
396 * @deprecated use the new AVFifo-API with av_fifo_drain2()
397 */
398 attribute_deprecated
399 void av_fifo_drain(AVFifoBuffer *f, int size);
400
401 #if FF_API_FIFO_PEEK2
402 /**
403 * Return a pointer to the data stored in a FIFO buffer at a certain offset.
404 * The FIFO buffer is not modified.
405 *
406 * @param f AVFifoBuffer to peek at, f must be non-NULL
407 * @param offs an offset in bytes, its absolute value must be less
408 * than the used buffer size or the returned pointer will
409 * point outside to the buffer data.
410 * The used buffer size can be checked with av_fifo_size().
411 * @deprecated use the new AVFifo-API with av_fifo_peek() or av_fifo_peek_to_cb()
412 */
413 attribute_deprecated
av_fifo_peek2(const AVFifoBuffer * f,int offs)414 static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
415 {
416 uint8_t *ptr = f->rptr + offs;
417 if (ptr >= f->end)
418 ptr = f->buffer + (ptr - f->end);
419 else if (ptr < f->buffer)
420 ptr = f->end - (f->buffer - ptr);
421 return ptr;
422 }
423 #endif
424 #endif
425
426 #endif /* AVUTIL_FIFO_H */
427