/* * 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 * a very simple circular buffer FIFO implementation */ #ifndef AVUTIL_FIFO_H #define AVUTIL_FIFO_H #include <stdint.h> #include "avutil.h" #include "attributes.h" typedef struct AVFifoBuffer { uint8_t *buffer; uint8_t *rptr, *wptr, *end; uint32_t rndx, wndx; } AVFifoBuffer; /** * Initialize an AVFifoBuffer. * @param size of FIFO * @return AVFifoBuffer or NULL in case of memory allocation failure */ AVFifoBuffer *av_fifo_alloc(unsigned int size); /** * Free an AVFifoBuffer. * @param f AVFifoBuffer to free */ void av_fifo_free(AVFifoBuffer *f); /** * Reset 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); /** * Return 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); /** * Return 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); /** * Feed 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)); /** * Feed data from a user-supplied callback to an AVFifoBuffer. * @param f AVFifoBuffer to write to * @param src data source; non-const since it may be used as a * modifiable context by the function defined in func * @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)); /** * Resize an AVFifoBuffer. * In case of reallocation failure, the old FIFO is kept unchanged. * * @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); /** * Enlarge an AVFifoBuffer. * In case of reallocation failure, the old FIFO is kept unchanged. * The new fifo size may be larger than the requested size. * * @param f AVFifoBuffer to resize * @param additional_space the amount of space in bytes to allocate in addition to av_fifo_size() * @return <0 for failure, >=0 otherwise */ int av_fifo_grow(AVFifoBuffer *f, unsigned int additional_space); /** * Read and discard 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); /** * Return a pointer to the data stored in a FIFO buffer at a certain offset. * The FIFO buffer is not modified. * * @param f AVFifoBuffer to peek at, f must be non-NULL * @param offs an offset in bytes, its absolute value must be less * than the used buffer size or the returned pointer will * point outside to the buffer data. * The used buffer size can be checked with av_fifo_size(). */ static inline uint8_t *av_fifo_peek2(const AVFifoBuffer *f, int offs) { uint8_t *ptr = f->rptr + offs; if (ptr >= f->end) ptr = f->buffer + (ptr - f->end); else if (ptr < f->buffer) ptr = f->end - (f->buffer - ptr); return ptr; } #if FF_API_AV_FIFO_PEEK /** * @deprecated Use av_fifo_peek2() instead. */ attribute_deprecated static inline uint8_t av_fifo_peek(AVFifoBuffer *f, int offs) { return *av_fifo_peek2(f, offs); } #endif #endif /* AVUTIL_FIFO_H */