2 * This file is part of FFmpeg.
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.
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.
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
21 * a very simple circular buffer FIFO implementation
30 typedef struct AVFifoBuffer {
32 uint8_t *rptr, *wptr, *end;
37 * Initialize an AVFifoBuffer.
39 * @return AVFifoBuffer or NULL in case of memory allocation failure
41 AVFifoBuffer *av_fifo_alloc(unsigned int size);
44 * Free an AVFifoBuffer.
45 * @param f AVFifoBuffer to free
47 void av_fifo_free(AVFifoBuffer *f);
50 * Reset the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied.
51 * @param f AVFifoBuffer to reset
53 void av_fifo_reset(AVFifoBuffer *f);
56 * Return the amount of data in bytes in the AVFifoBuffer, that is the
57 * amount of data you can read from it.
58 * @param f AVFifoBuffer to read from
61 int av_fifo_size(AVFifoBuffer *f);
64 * Return the amount of space in bytes in the AVFifoBuffer, that is the
65 * amount of data you can write into it.
66 * @param f AVFifoBuffer to write into
69 int av_fifo_space(AVFifoBuffer *f);
72 * Feed data from an AVFifoBuffer to a user-supplied callback.
73 * @param f AVFifoBuffer to read from
74 * @param buf_size number of bytes to read
75 * @param func generic read function
76 * @param dest data destination
78 int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
81 * Feed data from a user-supplied callback to an AVFifoBuffer.
82 * @param f AVFifoBuffer to write to
83 * @param src data source; non-const since it may be used as a
84 * modifiable context by the function defined in func
85 * @param size number of bytes to write
86 * @param func generic write function; the first parameter is src,
87 * the second is dest_buf, the third is dest_buf_size.
88 * func must return the number of bytes written to dest_buf, or <= 0 to
89 * indicate no more data available to write.
90 * If func is NULL, src is interpreted as a simple byte array for source data.
91 * @return the number of bytes written to the FIFO
93 int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int));
96 * Resize an AVFifoBuffer.
97 * In case of reallocation failure, the old FIFO is kept unchanged.
99 * @param f AVFifoBuffer to resize
100 * @param size new AVFifoBuffer size in bytes
101 * @return <0 for failure, >=0 otherwise
103 int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size);
106 * Enlarge an AVFifoBuffer.
107 * In case of reallocation failure, the old FIFO is kept unchanged.
108 * The new fifo size may be larger than the requested size.
110 * @param f AVFifoBuffer to resize
111 * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size()
112 * @return <0 for failure, >=0 otherwise
114 int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space);
117 * Read and discard the specified amount of data from an AVFifoBuffer.
118 * @param f AVFifoBuffer to read from
119 * @param size amount of data to read in bytes
121 void av_fifo_drain(AVFifoBuffer *f, int size);
124 * Return a pointer to the data stored in a FIFO buffer at a certain offset.
125 * The FIFO buffer is not modified.
127 * @param f AVFifoBuffer to peek at, f must be non-NULL
128 * @param offs an offset in bytes, its absolute value must be less
129 * than the used buffer size or the returned pointer will
130 * point outside to the buffer data.
131 * The used buffer size can be checked with av_fifo_size().
133 static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs)
135 uint8_t *ptr = f->rptr + offs;
137 ptr = f->buffer + (ptr - f->end);
138 else if (ptr < f->buffer)
139 ptr = f->end - (f->buffer - ptr);
143 #if FF_API_AV_FIFO_PEEK
145 * @deprecated Use av_fifo_peek2() instead.
148 static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs)
150 return *av_fifo_peek2(f, offs);
154 #endif /* AVUTIL_FIFO_H */