import com.google.android.exoplayer2.upstream.Allocation; //导入依赖的package包/类
/**
 * Reads data from the front of the rolling buffer.
 *
 * @param absolutePosition The absolute position from which data should be read.
 * @param target The array into which data should be written.
 * @param length The number of bytes to read.
 */
private void readData(long absolutePosition, byte[] target, int length) {
  advanceReadTo(absolutePosition);
  int remaining = length;
  while (remaining > 0) {
    int toCopy = Math.min(remaining, (int) (readAllocationNode.endPosition - absolutePosition));
    Allocation allocation = readAllocationNode.allocation;
    System.arraycopy(allocation.data, readAllocationNode.translateOffset(absolutePosition),
        target, length - remaining, toCopy);
    remaining -= toCopy;
    absolutePosition += toCopy;
    if (absolutePosition == readAllocationNode.endPosition) {
      readAllocationNode = readAllocationNode.next;
    }
  }
}
 

import com.google.android.exoplayer2.upstream.Allocation; //导入依赖的package包/类
/**
 * Clears allocation nodes starting from {@code fromNode}.
 *
 * @param fromNode The node from which to clear.
 */
private void clearAllocationNodes(AllocationNode fromNode) {
  if (!fromNode.wasInitialized) {
    return;
  }
  // Bulk release allocations for performance (it's significantly faster when using
  // DefaultAllocator because the allocator's lock only needs to be acquired and released once)
  // [Internal: See b/29542039].
  int allocationCount = (writeAllocationNode.wasInitialized ? 1 : 0)
      + ((int) (writeAllocationNode.startPosition - fromNode.startPosition) / allocationLength);
  Allocation[] allocationsToRelease = new Allocation[allocationCount];
  AllocationNode currentNode = fromNode;
  for (int i = 0; i < allocationsToRelease.length; i++) {
    allocationsToRelease[i] = currentNode.allocation;
    currentNode = currentNode.clear();
  }
  allocator.release(allocationsToRelease);
}
 

import com.google.android.exoplayer2.upstream.Allocation; //导入依赖的package包/类
/**
 * Reads data from the front of the rolling buffer.
 *
 * @param absolutePosition The absolute position from which data should be read.
 * @param target The buffer into which data should be written.
 * @param length The number of bytes to read.
 */
private void readData(long absolutePosition, ByteBuffer target, int length) {
  int remaining = length;
  while (remaining > 0) {
    dropDownstreamTo(absolutePosition);
    int positionInAllocation = (int) (absolutePosition - totalBytesDropped);
    int toCopy = Math.min(remaining, allocationLength - positionInAllocation);
    Allocation allocation = dataQueue.peek();
    target.put(allocation.data, allocation.translateOffset(positionInAllocation), toCopy);
    absolutePosition += toCopy;
    remaining -= toCopy;
  }
}
 

import com.google.android.exoplayer2.upstream.Allocation; //导入依赖的package包/类
private void clearSampleData() {
  infoQueue.clearSampleData();
  allocator.release(dataQueue.toArray(new Allocation[dataQueue.size()]));
  dataQueue.clear();
  allocator.trim();
  totalBytesDropped = 0;
  totalBytesWritten = 0;
  lastAllocation = null;
  lastAllocationOffset = allocationLength;
}
 

import com.google.android.exoplayer2.upstream.Allocation; //导入依赖的package包/类
private void clearSampleData() {
  infoQueue.clearSampleData();
  allocator.release(dataQueue.toArray(new Allocation[dataQueue.size()]));
  dataQueue.clear();
  allocator.trim();
  totalBytesDropped = 0;
  totalBytesWritten = 0;
  lastAllocation = null;
  lastAllocationOffset = allocationLength;
  needKeyframe = true;
}
 

import com.google.android.exoplayer2.upstream.Allocation; //导入依赖的package包/类
/**
 * Initializes the node.
 *
 * @param allocation The node's {@link Allocation}.
 * @param next The next {@link AllocationNode}.
 */
public void initialize(Allocation allocation, AllocationNode next) {
  this.allocation = allocation;
  this.next = next;
  wasInitialized = true;
}