Update public FFmpeg header files from r16647 to r18286.

third_party/ffmpeg/include/libavutil/fifo.h

 /*
  * 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 fifo.h
- * A very simple circular buffer FIFO implementation.
+ * @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 *f AVFifoBuffer to initialize
  * @param size of FIFO
- * @return <0 for failure >=0 otherwise
+ * @return AVFifoBuffer or NULL if mem allocation failure
  */
-int av_fifo_init(AVFifoBuffer *f, unsigned int size);
+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);
 
 /**
- * Reads data from an AVFifoBuffer.
- * @param *f AVFifoBuffer to read from
- * @param *buf data destination
- * @param buf_size number of bytes to read
- */
-int av_fifo_read(AVFifoBuffer *f, uint8_t *buf, int buf_size);
-
-/**
- * Feeds data from an AVFifoBuffer to a user supplied callback.
+ * 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, int buf_size, void (*func)(void*, void*, int), void* dest);
+int av_fifo_generic_read(AVFifoBuffer *f, void *dest, int buf_size, void (*func)(void*, void*, int));
 
 /**
- * Writes data into an AVFifoBuffer.
- * @param *f AVFifoBuffer to write to
- * @param *buf data source
- * @param size data size
- */
-attribute_deprecated void av_fifo_write(AVFifoBuffer *f, const uint8_t *buf, int size);
-
-/**
- * Feeds data from a user supplied callback to an AVFifoBuffer.
+ * 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. First parameter is src,
- * second is dest_buf, third is dest_buf_size.
+ * @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.
+ * @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));
 
-#if LIBAVUTIL_VERSION_MAJOR < 50
-/**
- * Resizes an AVFifoBuffer.
- * @param *f AVFifoBuffer to resize
- * @param size new AVFifoBuffer size in bytes
- * @see av_fifo_realloc2()
- */
-attribute_deprecated void av_fifo_realloc(AVFifoBuffer *f, unsigned int size);
-#endif
-
 /**
  * Resizes an AVFifoBuffer.
  * @param *f AVFifoBuffer to resize
  * @param size new AVFifoBuffer size in bytes
- * @return <0 for failure >=0 otherwise
+ * @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 */