Merging SeekableBuffer and BufferQueue

media/base/buffer_queue.cc

-// Copyright (c) 2009 The Chromium Authors. All rights reserved.
-// Use of this source code is governed by a BSD-style license that can be
-// found in the LICENSE file.
-
-#include "media/base/buffer_queue.h"
-
-#include "media/base/buffers.h"
-
-namespace media {
-
-BufferQueue::BufferQueue()
-    : data_offset_(0),
-      size_in_bytes_(0),
-      most_recent_time_() {
-}
-
-BufferQueue::~BufferQueue() {
-}
-
-void BufferQueue::Consume(size_t bytes_to_be_consumed) {
-  // Make sure user isn't trying to consume more than we have.
-  DCHECK(size_in_bytes_ >= bytes_to_be_consumed);
-
-  // As we have enough data to consume, adjust |size_in_bytes_|.
-  size_in_bytes_ -= bytes_to_be_consumed;
-
-  // Now consume them.
-  while (bytes_to_be_consumed > 0) {
-    // Calculate number of usable bytes in the front of the |queue_|.
-    size_t front_remaining = queue_.front()->GetDataSize() - data_offset_;
-
-    // If there is enough data in our first buffer to advance into it, do so.
-    // Otherwise, advance into the queue.
-    if (front_remaining > bytes_to_be_consumed) {
-      data_offset_ += bytes_to_be_consumed;
-      bytes_to_be_consumed = 0;
-      // Garbage values are unavoidable, so this check will remain.
-      if (queue_.front()->GetTimestamp().InMicroseconds() > 0) {
-        int64 offset = (queue_.front()->GetDuration().InMicroseconds() *
-            data_offset_) / queue_.front()->GetDataSize();
-
-        most_recent_time_ = queue_.front()->GetTimestamp() +
-            base::TimeDelta::FromMicroseconds(offset);
-      }
-    } else {
-      data_offset_ = 0;
-      // Garbage values are unavoidable, so this check will remain.
-      if (queue_.front()->GetTimestamp().InMicroseconds() > 0) {
-        most_recent_time_ = queue_.front()->GetTimestamp() +
-            queue_.front()->GetDuration();
-      }
-      queue_.pop_front();
-      bytes_to_be_consumed -= front_remaining;
-    }
-  }
-}
-
-size_t BufferQueue::Copy(uint8* dest, size_t bytes) {
-  if (bytes == 0)
-    return 0;
-
-  DCHECK(!queue_.empty());
-
-  size_t current_remaining = 0;
-  const uint8* current = NULL;
-  size_t copied = 0;
-
-  for (size_t i = 0; i < queue_.size() && bytes > 0; ++i) {
-    // Calculate number of usable bytes in the front of the |queue_|. Special
-    // case for front due to |data_offset_|.
-    if (i == 0) {
-      current_remaining = queue_.front()->GetDataSize() - data_offset_;
-      current = queue_.front()->GetData() + data_offset_;
-    } else {
-      current_remaining = queue_[i]->GetDataSize();
-      current = queue_[i]->GetData();
-    }
-
-    // Prevent writing over the end of the buffer.
-    if (current_remaining > bytes)
-      current_remaining = bytes;
-
-    memcpy(dest + copied, current, current_remaining);
-
-    // Modify counts and pointers.
-    copied += current_remaining;
-    bytes -= current_remaining;
-  }
-  return copied;
-}
-
-void BufferQueue::Enqueue(Buffer* buffer_in) {
-  if (queue_.empty() && buffer_in->GetTimestamp().InMicroseconds() > 0) {
-    most_recent_time_ = buffer_in->GetTimestamp();
-  }
-  queue_.push_back(buffer_in);
-  size_in_bytes_ += buffer_in->GetDataSize();
-}
-
-base::TimeDelta BufferQueue::GetTime() {
-  return most_recent_time_;
-}
-
-void BufferQueue::Clear() {
-  queue_.clear();
-  size_in_bytes_ = 0;
-  data_offset_ = 0;
-  most_recent_time_ = base::TimeDelta();
-}
-
-bool BufferQueue::IsEmpty() {
-  // Since we keep track of the number of bytes, this is easier than calling
-  // into |queue_|.
-  return size_in_bytes_ == 0;
-}
-
-size_t BufferQueue::SizeInBytes() {
-  return size_in_bytes_;
-}
-
-}  // namespace media