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The Tor Browser
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buffer_internal.h (3044B)

      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 #ifndef AVUTIL_BUFFER_INTERNAL_H
     20 #define AVUTIL_BUFFER_INTERNAL_H
     21 
     22 #include <stdatomic.h>
     23 #include <stdint.h>
     24 
     25 #include "buffer.h"
     26 #include "thread.h"
     27 
     28 /**
     29 * The buffer was av_realloc()ed, so it is reallocatable.
     30 */
     31 #define BUFFER_FLAG_REALLOCATABLE (1 << 0)
     32 /**
     33 * The AVBuffer structure is part of a larger structure
     34 * and should not be freed.
     35 */
     36 #define BUFFER_FLAG_NO_FREE       (1 << 1)
     37 
     38 struct AVBuffer {
     39    uint8_t *data; /**< data described by this buffer */
     40    size_t size; /**< size of data in bytes */
     41 
     42    /**
     43     *  number of existing AVBufferRef instances referring to this buffer
     44     */
     45    atomic_uint refcount;
     46 
     47    /**
     48     * a callback for freeing the data
     49     */
     50    void (*free)(void *opaque, uint8_t *data);
     51 
     52    /**
     53     * an opaque pointer, to be used by the freeing callback
     54     */
     55    void *opaque;
     56 
     57    /**
     58     * A combination of AV_BUFFER_FLAG_*
     59     */
     60    int flags;
     61 
     62    /**
     63     * A combination of BUFFER_FLAG_*
     64     */
     65    int flags_internal;
     66 };
     67 
     68 typedef struct BufferPoolEntry {
     69    uint8_t *data;
     70 
     71    /*
     72     * Backups of the original opaque/free of the AVBuffer corresponding to
     73     * data. They will be used to free the buffer when the pool is freed.
     74     */
     75    void *opaque;
     76    void (*free)(void *opaque, uint8_t *data);
     77 
     78    AVBufferPool *pool;
     79    struct BufferPoolEntry *next;
     80 
     81    /*
     82     * An AVBuffer structure to (re)use as AVBuffer for subsequent uses
     83     * of this BufferPoolEntry.
     84     */
     85    AVBuffer buffer;
     86 } BufferPoolEntry;
     87 
     88 struct AVBufferPool {
     89    AVMutex mutex;
     90    BufferPoolEntry *pool;
     91 
     92    /*
     93     * This is used to track when the pool is to be freed.
     94     * The pointer to the pool itself held by the caller is considered to
     95     * be one reference. Each buffer requested by the caller increases refcount
     96     * by one, returning the buffer to the pool decreases it by one.
     97     * refcount reaches zero when the buffer has been uninited AND all the
     98     * buffers have been released, then it's safe to free the pool and all
     99     * the buffers in it.
    100     */
    101    atomic_uint refcount;
    102 
    103    size_t size;
    104    void *opaque;
    105    AVBufferRef* (*alloc)(size_t size);
    106    AVBufferRef* (*alloc2)(void *opaque, size_t size);
    107    void         (*pool_free)(void *opaque);
    108 };
    109 
    110 #endif /* AVUTIL_BUFFER_INTERNAL_H */