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 <stdint.h> 28 29typedef struct AVFifoBuffer { 30 uint8_t *buffer; 31 uint8_t *rptr, *wptr, *end; 32 uint32_t rndx, wndx; 33} AVFifoBuffer; 34 35/** 36 * Initializes an AVFifoBuffer. 37 * @param size of FIFO 38 * @return AVFifoBuffer or NULL in case of memory allocation failure 39 */ 40AVFifoBuffer *av_fifo_alloc(unsigned int size); 41 42/** 43 * Frees an AVFifoBuffer. 44 * @param *f AVFifoBuffer to free 45 */ 46void av_fifo_free(AVFifoBuffer *f); 47 48/** 49 * Resets the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied. 50 * @param *f AVFifoBuffer to reset 51 */ 52void av_fifo_reset(AVFifoBuffer *f); 53 54/** 55 * Returns the amount of data in bytes in the AVFifoBuffer, that is the 56 * amount of data you can read from it. 57 * @param *f AVFifoBuffer to read from 58 * @return size 59 */ 60int av_fifo_size(AVFifoBuffer *f); 61 62/** 63 * Returns the amount of space in bytes in the AVFifoBuffer, that is the 64 * amount of data you can write into it. 65 * @param *f AVFifoBuffer to write into 66 * @return size 67 */ 68int av_fifo_space(AVFifoBuffer *f); 69 70/** 71 * Feeds data from an AVFifoBuffer to a user-supplied callback. 72 * @param *f AVFifoBuffer to read from 73 * @param buf_size number of bytes to read 74 * @param *func generic read function 75 * @param *dest data destination 76 */ 77int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int)); 78 79/** 80 * Feeds data from a user-supplied callback to an AVFifoBuffer. 81 * @param *f AVFifoBuffer to write to 82 * @param *src data source; non-const since it may be used as a 83 * modifiable context by the function defined in func 84 * @param size number of bytes to write 85 * @param *func generic write function; the first parameter is src, 86 * the second is dest_buf, the third is dest_buf_size. 87 * func must return the number of bytes written to dest_buf, or <= 0 to 88 * indicate no more data available to write. 89 * If func is NULL, src is interpreted as a simple byte array for source data. 90 * @return the number of bytes written to the FIFO 91 */ 92int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int)); 93 94/** 95 * Resizes an AVFifoBuffer. 96 * @param *f AVFifoBuffer to resize 97 * @param size new AVFifoBuffer size in bytes 98 * @return <0 for failure, >=0 otherwise 99 */ 100int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size); 101 102/** 103 * Reads and discards the specified amount of data from an AVFifoBuffer. 104 * @param *f AVFifoBuffer to read from 105 * @param size amount of data to read in bytes 106 */ 107void av_fifo_drain(AVFifoBuffer *f, int size); 108 109static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs) 110{ 111 uint8_t *ptr = f->rptr + offs; 112 if (ptr >= f->end) 113 ptr -= f->end - f->buffer; 114 return *ptr; 115} 116#endif /* AVUTIL_FIFO_H */ 117