content: /*
   * Copyright (C) 2016 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package com.google.android.exoplayer2.decoder;
  
  import android.support.annotation.IntDef;
  import com.google.android.exoplayer2.C;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  import java.nio.ByteBuffer;
  
  /**
   * Holds input for a decoder.
   */
  public class DecoderInputBuffer extends Buffer {
  
    /**
     * The buffer replacement mode, which may disable replacement.
     */
    @Retention(RetentionPolicy.SOURCE)
    @IntDef({BUFFER_REPLACEMENT_MODE_DISABLED, BUFFER_REPLACEMENT_MODE_NORMAL,
        BUFFER_REPLACEMENT_MODE_DIRECT})
    public @interface BufferReplacementMode {}
    /**
     * Disallows buffer replacement.
     */
    public static final int BUFFER_REPLACEMENT_MODE_DISABLED = 0;
    /**
     * Allows buffer replacement using {@link ByteBuffer#allocate(int)}.
     */
    public static final int BUFFER_REPLACEMENT_MODE_NORMAL = 1;
    /**
     * Allows buffer replacement using {@link ByteBuffer#allocateDirect(int)}.
     */
    public static final int BUFFER_REPLACEMENT_MODE_DIRECT = 2;
  
    /**
     * {@link CryptoInfo} for encrypted data.
     */
    public final CryptoInfo cryptoInfo;
  
    /**
     * The buffer's data, or {@code null} if no data has been set.
     */
    public ByteBuffer data;
  
    /**
     * The time at which the sample should be presented.
     */
    public long timeUs;
  
    @BufferReplacementMode private final int bufferReplacementMode;
  
    /**
     * Creates a new instance for which {@link #isFlagsOnly()} will return true.
     *
     * @return A new flags only input buffer.
     */
    public static DecoderInputBuffer newFlagsOnlyInstance() {
      return new DecoderInputBuffer(BUFFER_REPLACEMENT_MODE_DISABLED);
    }
  
    /**
     * @param bufferReplacementMode Determines the behavior of {@link #ensureSpaceForWrite(int)}. One
     *     of {@link #BUFFER_REPLACEMENT_MODE_DISABLED}, {@link #BUFFER_REPLACEMENT_MODE_NORMAL} and
     *     {@link #BUFFER_REPLACEMENT_MODE_DIRECT}.
     */
    public DecoderInputBuffer(@BufferReplacementMode int bufferReplacementMode) {
      this.cryptoInfo = new CryptoInfo();
      this.bufferReplacementMode = bufferReplacementMode;
    }
  
    /**
     * Ensures that {@link #data} is large enough to accommodate a write of a given length at its
     * current position.
     * <p>
     * If the capacity of {@link #data} is sufficient this method does nothing. If the capacity is
     * insufficient then an attempt is made to replace {@link #data} with a new {@link ByteBuffer}
     * whose capacity is sufficient. Data up to the current position is copied to the new buffer.
     *
     * @param length The length of the write that must be accommodated, in bytes.
     * @throws IllegalStateException If there is insufficient capacity to accommodate the write and
     *     the buffer replacement mode of the holder is {@link #BUFFER_REPLACEMENT_MODE_DISABLED}.
     */
    public void ensureSpaceForWrite(int length) throws IllegalStateException {
      if (data == null) {
        data = createReplacementByteBuffer(length);
        return;
      }
      // Check whether the current buffer is sufficient.
      int capacity = data.capacity();
      int position = data.position();
      int requiredCapacity = position + length;
      if (capacity >= requiredCapacity) {
        return;
      }
      // Instantiate a new buffer if possible.
      ByteBuffer newData = createReplacementByteBuffer(requiredCapacity);
      // Copy data up to the current position from the old buffer to the new one.
      if (position > 0) {
        data.position(0);
        data.limit(position);
        newData.put(data);
      }
      // Set the new buffer.
      data = newData;
    }
  
    /**
     * Returns whether the buffer is only able to hold flags, meaning {@link #data} is null and
     * its replacement mode is {@link #BUFFER_REPLACEMENT_MODE_DISABLED}.
     */
    public final boolean isFlagsOnly() {
      return data == null && bufferReplacementMode == BUFFER_REPLACEMENT_MODE_DISABLED;
    }
  
    /**
     * Returns whether the {@link C#BUFFER_FLAG_ENCRYPTED} flag is set.
     */
    public final boolean isEncrypted() {
      return getFlag(C.BUFFER_FLAG_ENCRYPTED);
    }
  
    /**
     * Flips {@link #data} in preparation for being queued to a decoder.
     *
     * @see java.nio.Buffer#flip()
     */
    public final void flip() {
      data.flip();
    }
  
    @Override
    public void clear() {
      super.clear();
      if (data != null) {
        data.clear();
      }
    }
  
    private ByteBuffer createReplacementByteBuffer(int requiredCapacity) {
      if (bufferReplacementMode == BUFFER_REPLACEMENT_MODE_NORMAL) {
        return ByteBuffer.allocate(requiredCapacity);
      } else if (bufferReplacementMode == BUFFER_REPLACEMENT_MODE_DIRECT) {
        return ByteBuffer.allocateDirect(requiredCapacity);
      } else {
        int currentCapacity = data == null ? 0 : data.capacity();
        throw new IllegalStateException("Buffer too small (" + currentCapacity + " < "
            + requiredCapacity + ")");
      }
    }
  
  }
  