FFmpeg 6.1.1
fifo.h
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16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19/**
20 * @file
21 * @ingroup lavu_fifo
22 * A generic FIFO API
23 */
24
25#ifndef AVUTIL_FIFO_H
26#define AVUTIL_FIFO_H
27
28#include <stddef.h>
29#include <stdint.h>
30
31#include "attributes.h"
32#include "version.h"
33
34/**
35 * @defgroup lavu_fifo AVFifo
36 * @ingroup lavu_data
37 *
38 * @{
39 * A generic FIFO API
40 */
41
42typedef struct AVFifo AVFifo;
43
44/**
45 * Callback for writing or reading from a FIFO, passed to (and invoked from) the
46 * av_fifo_*_cb() functions. It may be invoked multiple times from a single
47 * av_fifo_*_cb() call and may process less data than the maximum size indicated
48 * by nb_elems.
49 *
50 * @param opaque the opaque pointer provided to the av_fifo_*_cb() function
51 * @param buf the buffer for reading or writing the data, depending on which
52 * av_fifo_*_cb function is called
53 * @param nb_elems On entry contains the maximum number of elements that can be
54 * read from / written into buf. On success, the callback should
55 * update it to contain the number of elements actually written.
56 *
57 * @return 0 on success, a negative error code on failure (will be returned from
58 * the invoking av_fifo_*_cb() function)
59 */
60typedef int AVFifoCB(void *opaque, void *buf, size_t *nb_elems);
61
62/**
63 * Automatically resize the FIFO on writes, so that the data fits. This
64 * automatic resizing happens up to a limit that can be modified with
65 * av_fifo_auto_grow_limit().
66 */
67#define AV_FIFO_FLAG_AUTO_GROW (1 << 0)
68
69/**
70 * Allocate and initialize an AVFifo with a given element size.
71 *
72 * @param elems initial number of elements that can be stored in the FIFO
73 * @param elem_size Size in bytes of a single element. Further operations on
74 * the returned FIFO will implicitly use this element size.
75 * @param flags a combination of AV_FIFO_FLAG_*
76 *
77 * @return newly-allocated AVFifo on success, a negative error code on failure
78 */
79AVFifo *av_fifo_alloc2(size_t elems, size_t elem_size,
80 unsigned int flags);
81
82/**
83 * @return Element size for FIFO operations. This element size is set at
84 * FIFO allocation and remains constant during its lifetime
85 */
86size_t av_fifo_elem_size(const AVFifo *f);
87
88/**
89 * Set the maximum size (in elements) to which the FIFO can be resized
90 * automatically. Has no effect unless AV_FIFO_FLAG_AUTO_GROW is used.
91 */
92void av_fifo_auto_grow_limit(AVFifo *f, size_t max_elems);
93
94/**
95 * @return number of elements available for reading from the given FIFO.
96 */
97size_t av_fifo_can_read(const AVFifo *f);
98
99/**
100 * @return Number of elements that can be written into the given FIFO without
101 * growing it.
102 *
103 * In other words, this number of elements or less is guaranteed to fit
104 * into the FIFO. More data may be written when the
105 * AV_FIFO_FLAG_AUTO_GROW flag was specified at FIFO creation, but this
106 * may involve memory allocation, which can fail.
107 */
108size_t av_fifo_can_write(const AVFifo *f);
109
110/**
111 * Enlarge an AVFifo.
112 *
113 * On success, the FIFO will be large enough to hold exactly
114 * inc + av_fifo_can_read() + av_fifo_can_write()
115 * elements. In case of failure, the old FIFO is kept unchanged.
116 *
117 * @param f AVFifo to resize
118 * @param inc number of elements to allocate for, in addition to the current
119 * allocated size
120 * @return a non-negative number on success, a negative error code on failure
121 */
122int av_fifo_grow2(AVFifo *f, size_t inc);
123
124/**
125 * Write data into a FIFO.
126 *
127 * In case nb_elems > av_fifo_can_write(f) and the AV_FIFO_FLAG_AUTO_GROW flag
128 * was not specified at FIFO creation, nothing is written and an error
129 * is returned.
130 *
131 * Calling function is guaranteed to succeed if nb_elems <= av_fifo_can_write(f).
132 *
133 * @param f the FIFO buffer
134 * @param buf Data to be written. nb_elems * av_fifo_elem_size(f) bytes will be
135 * read from buf on success.
136 * @param nb_elems number of elements to write into FIFO
137 *
138 * @return a non-negative number on success, a negative error code on failure
139 */
140int av_fifo_write(AVFifo *f, const void *buf, size_t nb_elems);
141
142/**
143 * Write data from a user-provided callback into a FIFO.
144 *
145 * @param f the FIFO buffer
146 * @param read_cb Callback supplying the data to the FIFO. May be called
147 * multiple times.
148 * @param opaque opaque user data to be provided to read_cb
149 * @param nb_elems Should point to the maximum number of elements that can be
150 * written. Will be updated to contain the number of elements
151 * actually written.
152 *
153 * @return non-negative number on success, a negative error code on failure
154 */
156 void *opaque, size_t *nb_elems);
157
158/**
159 * Read data from a FIFO.
160 *
161 * In case nb_elems > av_fifo_can_read(f), nothing is read and an error
162 * is returned.
163 *
164 * @param f the FIFO buffer
165 * @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes
166 * will be written into buf on success.
167 * @param nb_elems number of elements to read from FIFO
168 *
169 * @return a non-negative number on success, a negative error code on failure
170 */
171int av_fifo_read(AVFifo *f, void *buf, size_t nb_elems);
172
173/**
174 * Feed data from a FIFO into a user-provided callback.
175 *
176 * @param f the FIFO buffer
177 * @param write_cb Callback the data will be supplied to. May be called
178 * multiple times.
179 * @param opaque opaque user data to be provided to write_cb
180 * @param nb_elems Should point to the maximum number of elements that can be
181 * read. Will be updated to contain the total number of elements
182 * actually sent to the callback.
183 *
184 * @return non-negative number on success, a negative error code on failure
185 */
187 void *opaque, size_t *nb_elems);
188
189/**
190 * Read data from a FIFO without modifying FIFO state.
191 *
192 * Returns an error if an attempt is made to peek to nonexistent elements
193 * (i.e. if offset + nb_elems is larger than av_fifo_can_read(f)).
194 *
195 * @param f the FIFO buffer
196 * @param buf Buffer to store the data. nb_elems * av_fifo_elem_size(f) bytes
197 * will be written into buf.
198 * @param nb_elems number of elements to read from FIFO
199 * @param offset number of initial elements to skip.
200 *
201 * @return a non-negative number on success, a negative error code on failure
202 */
203int av_fifo_peek(const AVFifo *f, void *buf, size_t nb_elems, size_t offset);
204
205/**
206 * Feed data from a FIFO into a user-provided callback.
207 *
208 * @param f the FIFO buffer
209 * @param write_cb Callback the data will be supplied to. May be called
210 * multiple times.
211 * @param opaque opaque user data to be provided to write_cb
212 * @param nb_elems Should point to the maximum number of elements that can be
213 * read. Will be updated to contain the total number of elements
214 * actually sent to the callback.
215 * @param offset number of initial elements to skip; offset + *nb_elems must not
216 * be larger than av_fifo_can_read(f).
217 *
218 * @return a non-negative number on success, a negative error code on failure
219 */
220int av_fifo_peek_to_cb(const AVFifo *f, AVFifoCB write_cb, void *opaque,
221 size_t *nb_elems, size_t offset);
222
223/**
224 * Discard the specified amount of data from an AVFifo.
225 * @param size number of elements to discard, MUST NOT be larger than
226 * av_fifo_can_read(f)
227 */
228void av_fifo_drain2(AVFifo *f, size_t size);
229
230/*
231 * Empty the AVFifo.
232 * @param f AVFifo to reset
233 */
235
236/**
237 * Free an AVFifo and reset pointer to NULL.
238 * @param f Pointer to an AVFifo to free. *f == NULL is allowed.
239 */
241
242
243#if FF_API_FIFO_OLD_API
244typedef struct AVFifoBuffer {
245 uint8_t *buffer;
246 uint8_t *rptr, *wptr, *end;
247 uint32_t rndx, wndx;
249
250/**
251 * Initialize an AVFifoBuffer.
252 * @param size of FIFO
253 * @return AVFifoBuffer or NULL in case of memory allocation failure
254 * @deprecated use av_fifo_alloc2()
255 */
257AVFifoBuffer *av_fifo_alloc(unsigned int size);
258
259/**
260 * Initialize an AVFifoBuffer.
261 * @param nmemb number of elements
262 * @param size size of the single element
263 * @return AVFifoBuffer or NULL in case of memory allocation failure
264 * @deprecated use av_fifo_alloc2()
265 */
267AVFifoBuffer *av_fifo_alloc_array(size_t nmemb, size_t size);
268
269/**
270 * Free an AVFifoBuffer.
271 * @param f AVFifoBuffer to free
272 * @deprecated use the AVFifo API with av_fifo_freep2()
273 */
276
277/**
278 * Free an AVFifoBuffer and reset pointer to NULL.
279 * @param f AVFifoBuffer to free
280 * @deprecated use the AVFifo API with av_fifo_freep2()
281 */
284
285/**
286 * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
287 * @param f AVFifoBuffer to reset
288 * @deprecated use av_fifo_reset2() with the new AVFifo-API
289 */
292
293/**
294 * Return the amount of data in bytes in the AVFifoBuffer, that is the
295 * amount of data you can read from it.
296 * @param f AVFifoBuffer to read from
297 * @return size
298 * @deprecated use av_fifo_can_read() with the new AVFifo-API
299 */
302
303/**
304 * Return the amount of space in bytes in the AVFifoBuffer, that is the
305 * amount of data you can write into it.
306 * @param f AVFifoBuffer to write into
307 * @return size
308 * @deprecated use av_fifo_can_write() with the new AVFifo-API
309 */
312
313/**
314 * Feed data at specific position from an AVFifoBuffer to a user-supplied callback.
315 * Similar as av_fifo_gereric_read but without discarding data.
316 * @param f AVFifoBuffer to read from
317 * @param offset offset from current read position
318 * @param buf_size number of bytes to read
319 * @param func generic read function
320 * @param dest data destination
321 *
322 * @return a non-negative number on success, a negative error code on failure
323 *
324 * @deprecated use the new AVFifo-API with av_fifo_peek() when func == NULL,
325 * av_fifo_peek_to_cb() otherwise
326 */
328int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void (*func)(void*, void*, int));
329
330/**
331 * Feed data from an AVFifoBuffer to a user-supplied callback.
332 * Similar as av_fifo_gereric_read but without discarding data.
333 * @param f AVFifoBuffer to read from
334 * @param buf_size number of bytes to read
335 * @param func generic read function
336 * @param dest data destination
337 *
338 * @return a non-negative number on success, a negative error code on failure
339 *
340 * @deprecated use the new AVFifo-API with av_fifo_peek() when func == NULL,
341 * av_fifo_peek_to_cb() otherwise
342 */
344int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
345
346/**
347 * Feed data from an AVFifoBuffer to a user-supplied callback.
348 * @param f AVFifoBuffer to read from
349 * @param buf_size number of bytes to read
350 * @param func generic read function
351 * @param dest data destination
352 *
353 * @return a non-negative number on success, a negative error code on failure
354 *
355 * @deprecated use the new AVFifo-API with av_fifo_read() when func == NULL,
356 * av_fifo_read_to_cb() otherwise
357 */
359int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
360
361/**
362 * Feed data from a user-supplied callback to an AVFifoBuffer.
363 * @param f AVFifoBuffer to write to
364 * @param src data source; non-const since it may be used as a
365 * modifiable context by the function defined in func
366 * @param size number of bytes to write
367 * @param func generic write function; the first parameter is src,
368 * the second is dest_buf, the third is dest_buf_size.
369 * func must return the number of bytes written to dest_buf, or <= 0 to
370 * indicate no more data available to write.
371 * If func is NULL, src is interpreted as a simple byte array for source data.
372 * @return the number of bytes written to the FIFO or a negative error code on failure
373 *
374 * @deprecated use the new AVFifo-API with av_fifo_write() when func == NULL,
375 * av_fifo_write_from_cb() otherwise
376 */
378int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
379
380/**
381 * Resize an AVFifoBuffer.
382 * In case of reallocation failure, the old FIFO is kept unchanged.
383 *
384 * @param f AVFifoBuffer to resize
385 * @param size new AVFifoBuffer size in bytes
386 * @return <0 for failure, >=0 otherwise
387 *
388 * @deprecated use the new AVFifo-API with av_fifo_grow2() to increase FIFO size,
389 * decreasing FIFO size is not supported
390 */
392int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
393
394/**
395 * Enlarge an AVFifoBuffer.
396 * In case of reallocation failure, the old FIFO is kept unchanged.
397 * The new fifo size may be larger than the requested size.
398 *
399 * @param f AVFifoBuffer to resize
400 * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
401 * @return <0 for failure, >=0 otherwise
402 *
403 * @deprecated use the new AVFifo-API with av_fifo_grow2(); note that unlike
404 * this function it adds to the allocated size, rather than to the used size
405 */
407int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);
408
409/**
410 * Read and discard the specified amount of data from an AVFifoBuffer.
411 * @param f AVFifoBuffer to read from
412 * @param size amount of data to read in bytes
413 *
414 * @deprecated use the new AVFifo-API with av_fifo_drain2()
415 */
417void av_fifo_drain(AVFifoBuffer *f, int size);
418
419#if FF_API_FIFO_PEEK2
420/**
421 * Return a pointer to the data stored in a FIFO buffer at a certain offset.
422 * The FIFO buffer is not modified.
423 *
424 * @param f AVFifoBuffer to peek at, f must be non-NULL
425 * @param offs an offset in bytes, its absolute value must be less
426 * than the used buffer size or the returned pointer will
427 * point outside to the buffer data.
428 * The used buffer size can be checked with av_fifo_size().
429 * @deprecated use the new AVFifo-API with av_fifo_peek() or av_fifo_peek_to_cb()
430 */
432static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
433{
434 uint8_t *ptr = f->rptr + offs;
435 if (ptr >= f->end)
436 ptr = f->buffer + (ptr - f->end);
437 else if (ptr < f->buffer)
438 ptr = f->end - (f->buffer - ptr);
439 return ptr;
440}
441#endif
442#endif
443
444/**
445 * @}
446 */
447
448#endif /* AVUTIL_FIFO_H */
Macro definitions for various function/variable attributes.
#define attribute_deprecated
Definition: attributes.h:100
attribute_deprecated int av_fifo_generic_peek_at(AVFifoBuffer *f, void *dest, int offset, int buf_size, void(*func)(void *, void *, int))
Feed data at specific position from an AVFifoBuffer to a user-supplied callback.
attribute_deprecated void av_fifo_freep(AVFifoBuffer **f)
Free an AVFifoBuffer and reset pointer to NULL.
AVFifo * av_fifo_alloc2(size_t elems, size_t elem_size, unsigned int flags)
Allocate and initialize an AVFifo with a given element size.
void av_fifo_freep2(AVFifo **f)
Free an AVFifo and reset pointer to NULL.
attribute_deprecated int av_fifo_space(const AVFifoBuffer *f)
Return the amount of space in bytes in the AVFifoBuffer, that is the amount of data you can write int...
attribute_deprecated int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space)
Enlarge an AVFifoBuffer.
void av_fifo_reset2(AVFifo *f)
attribute_deprecated int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int(*func)(void *, void *, int))
Feed data from a user-supplied callback to an AVFifoBuffer.
size_t av_fifo_can_write(const AVFifo *f)
attribute_deprecated int av_fifo_generic_peek(AVFifoBuffer *f, void *dest, int buf_size, void(*func)(void *, void *, int))
Feed data from an AVFifoBuffer to a user-supplied callback.
size_t av_fifo_can_read(const AVFifo *f)
attribute_deprecated AVFifoBuffer * av_fifo_alloc_array(size_t nmemb, size_t size)
Initialize an AVFifoBuffer.
attribute_deprecated void av_fifo_reset(AVFifoBuffer *f)
Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
attribute_deprecated int av_fifo_size(const AVFifoBuffer *f)
Return the amount of data in bytes in the AVFifoBuffer, that is the amount of data you can read from ...
attribute_deprecated int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void(*func)(void *, void *, int))
Feed data from an AVFifoBuffer to a user-supplied callback.
int av_fifo_peek(const AVFifo *f, void *buf, size_t nb_elems, size_t offset)
Read data from a FIFO without modifying FIFO state.
int av_fifo_read_to_cb(AVFifo *f, AVFifoCB write_cb, void *opaque, size_t *nb_elems)
Feed data from a FIFO into a user-provided callback.
static attribute_deprecated uint8_t * av_fifo_peek2(const AVFifoBuffer *f, int offs)
Return a pointer to the data stored in a FIFO buffer at a certain offset.
Definition: fifo.h:432
size_t av_fifo_elem_size(const AVFifo *f)
attribute_deprecated int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size)
Resize an AVFifoBuffer.
int av_fifo_write_from_cb(AVFifo *f, AVFifoCB read_cb, void *opaque, size_t *nb_elems)
Write data from a user-provided callback into a FIFO.
int av_fifo_grow2(AVFifo *f, size_t inc)
Enlarge an AVFifo.
struct AVFifo AVFifo
Definition: fifo.h:42
int av_fifo_peek_to_cb(const AVFifo *f, AVFifoCB write_cb, void *opaque, size_t *nb_elems, size_t offset)
Feed data from a FIFO into a user-provided callback.
int AVFifoCB(void *opaque, void *buf, size_t *nb_elems)
Callback for writing or reading from a FIFO, passed to (and invoked from) the av_fifo_*_cb() function...
Definition: fifo.h:60
int av_fifo_write(AVFifo *f, const void *buf, size_t nb_elems)
Write data into a FIFO.
void av_fifo_auto_grow_limit(AVFifo *f, size_t max_elems)
Set the maximum size (in elements) to which the FIFO can be resized automatically.
attribute_deprecated void av_fifo_drain(AVFifoBuffer *f, int size)
Read and discard the specified amount of data from an AVFifoBuffer.
void av_fifo_drain2(AVFifo *f, size_t size)
Discard the specified amount of data from an AVFifo.
attribute_deprecated AVFifoBuffer * av_fifo_alloc(unsigned int size)
Initialize an AVFifoBuffer.
attribute_deprecated void av_fifo_free(AVFifoBuffer *f)
Free an AVFifoBuffer.
int av_fifo_read(AVFifo *f, void *buf, size_t nb_elems)
Read data from a FIFO.
swscale version macros
uint8_t * wptr
Definition: fifo.h:246
uint8_t * rptr
Definition: fifo.h:246
uint8_t * buffer
Definition: fifo.h:245
uint32_t rndx
Definition: fifo.h:247
uint32_t wndx
Definition: fifo.h:247
uint8_t * end
Definition: fifo.h:246