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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_BYTE_QUEUE_H_
#define MEDIA_BASE_BYTE_QUEUE_H_
#include <stddef.h>
#include <stdint.h>
#include "base/containers/heap_array.h"
#include "base/containers/span.h"
#include "base/memory/raw_span.h"
#include "base/process/memory.h"
#include "media/base/media_export.h"
namespace media {
// Represents a queue of bytes. Data is added to the end of the queue via an
// Push() call and removed via Pop(). The contents of the queue can be observed
// via the Data() method.
//
// This class manages the underlying storage of the queue and tries to minimize
// the number of buffer copies when data is appended and removed.
class MEDIA_EXPORT ByteQueue {
public:
ByteQueue();
ByteQueue(const ByteQueue&) = delete;
ByteQueue& operator=(const ByteQueue&) = delete;
~ByteQueue();
// Reset the queue to the empty state.
void Reset();
// Appends new bytes onto the end of the queue. If allocation failure occurs,
// then the append of `data` is not done and returns false. Otherwise, returns
// true.
[[nodiscard]] bool Push(base::span<const uint8_t> data);
// Remove |count| bytes from the front of the queue.
void Pop(int count);
// Get a read-only span view of the data. This is only valid until the next
// Push() or Pop() call.
base::span<const uint8_t> Data() const { return data_; }
private:
// Offset from the start of |buffer_| that marks the front of the queue.
size_t offset_ = 0u;
base::HeapArray<uint8_t, base::UncheckedFreeDeleter> buffer_;
// Points to a certain piece of data in the `buffer_`
base::raw_span<uint8_t> data_;
};
} // namespace media
#endif // MEDIA_BASE_BYTE_QUEUE_H_
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