/* * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file libavutil/fifo.h * a very simple circular buffer FIFO implementation */ #ifndef AVUTIL_FIFO_H #define AVUTIL_FIFO_H #include <stdint.h> #include "avutil.h" #include "common.h" typedef struct AVFifoBuffer { uint8_t *buffer; uint8_t *rptr, *wptr, *end; uint32_t rndx, wndx; } AVFifoBuffer; /** * Initializes an AVFifoBuffer. * @param size of FIFO * @return AVFifoBuffer or NULL if mem allocation failure */ AVFifoBuffer *av_fifo_alloc(unsigned int size); /** * Frees an AVFifoBuffer. * @param *f AVFifoBuffer to free */ void av_fifo_free(AVFifoBuffer *f); /** * Resets the AVFifoBuffer to the state right after av_fifo_alloc, in particular it is emptied. * @param *f AVFifoBuffer to reset */ void av_fifo_reset(AVFifoBuffer *f); /** * Returns the amount of data in bytes in the AVFifoBuffer, that is the * amount of data you can read from it. * @param *f AVFifoBuffer to read from * @return size */ int av_fifo_size(AVFifoBuffer *f); /** * Returns the amount of space in bytes in the AVFifoBuffer, that is the * amount of data you can write into it. * @param *f AVFifoBuffer to write into * @return size */ int av_fifo_space(AVFifoBuffer *f); /** * Feeds data from an AVFifoBuffer to a user-supplied callback. * @param *f AVFifoBuffer to read from * @param buf_size number of bytes to read * @param *func generic read function * @param *dest data destination */ int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int)); /** * Feeds data from a user-supplied callback to an AVFifoBuffer. * @param *f AVFifoBuffer to write to * @param *src data source * @param size number of bytes to write * @param *func generic write function; the first parameter is src, * the second is dest_buf, the third is dest_buf_size. * func must return the number of bytes written to dest_buf, or <= 0 to * indicate no more data available to write. * If func is NULL, src is interpreted as a simple byte array for source data. * @return the number of bytes written to the FIFO */ int av_fifo_generic_write(AVFifoBuffer *f, void *src, int size, int (*func)(void*, void*, int)); /** * Resizes an AVFifoBuffer. * @param *f AVFifoBuffer to resize * @param size new AVFifoBuffer size in bytes * @return <0 for failure, >=0 otherwise */ int av_fifo_realloc2(AVFifoBuffer *f, unsigned int size); /** * Reads and discards the specified amount of data from an AVFifoBuffer. * @param *f AVFifoBuffer to read from * @param size amount of data to read in bytes */ void av_fifo_drain(AVFifoBuffer *f, int size); static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs) { uint8_t *ptr = f->rptr + offs; if (ptr >= f->end) ptr -= f->end - f->buffer; return *ptr; } #endif /* AVUTIL_FIFO_H */