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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef MEDIA_BASE_DECODER_BUFFER_QUEUE_H_
#define MEDIA_BASE_DECODER_BUFFER_QUEUE_H_
#include <stddef.h>
#include "base/containers/circular_deque.h"
#include "base/memory/scoped_refptr.h"
#include "base/time/time.h"
#include "media/base/media_export.h"
namespace media {
class DecoderBuffer;
// Maintains a queue of DecoderBuffers in increasing timestamp order.
//
// Individual buffer durations are ignored when calculating the duration of the
// queue i.e., the queue must have at least 2 in-order buffers to calculate
// duration.
//
// Not thread safe: access must be externally synchronized.
class MEDIA_EXPORT DecoderBufferQueue {
public:
DecoderBufferQueue();
DecoderBufferQueue(const DecoderBufferQueue&) = delete;
DecoderBufferQueue& operator=(const DecoderBufferQueue&) = delete;
~DecoderBufferQueue();
// Push |buffer| to the end of the queue. If |buffer| is queued out of order
// it will be excluded from duration calculations.
//
// It is invalid to push an end-of-stream |buffer|.
void Push(scoped_refptr<DecoderBuffer> buffer);
// Pops a DecoderBuffer from the front of the queue.
//
// It is invalid to call Pop() on an empty queue.
scoped_refptr<DecoderBuffer> Pop();
// Removes all queued buffers.
void Clear();
// Returns true if this queue is empty.
bool IsEmpty();
// Returns the duration of encoded data stored in this queue as measured by
// the timestamps of the earliest and latest buffers, ignoring out of order
// buffers.
//
// Returns zero if the queue is empty.
base::TimeDelta Duration();
// Returns the total memory occupied by this class and the buffers it holds,
// including the bookkeeping data and buffered data. For simplicity, the
// bookkeeping data of this class itself isn't included as it's relatively
// small compared to the other data.
size_t memory_usage_in_bytes() const { return memory_usage_in_bytes_; }
// Returns the number of buffers in the queue.
size_t queue_size() const { return queue_.size(); }
private:
using Queue = base::circular_deque<scoped_refptr<DecoderBuffer>>;
Queue queue_;
// A subset of |queue_| that contains buffers that are in strictly
// increasing timestamp order. Used to calculate Duration() while ignoring
// out-of-order buffers.
Queue in_order_queue_;
base::TimeDelta earliest_valid_timestamp_;
// Total memory usage in bytes for buffers in the queue.
size_t memory_usage_in_bytes_ = 0;
};
} // namespace media
#endif // MEDIA_BASE_DECODER_BUFFER_QUEUE_H_
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