content: /*
   * Copyright 2020 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.extractor.jpeg;
  
  import static com.google.android.exoplayer2.util.Assertions.checkArgument;
  
  import com.google.android.exoplayer2.extractor.ExtractorInput;
  import com.google.android.exoplayer2.extractor.ForwardingExtractorInput;
  
  /**
   * An extractor input that wraps another extractor input and exposes data starting at a given start
   * byte offset.
   *
   * <p>This is useful for reading data from a container that's concatenated after some prefix data
   * but where the container's extractor doesn't handle a non-zero start offset (for example, because
   * it seeks to absolute positions read from the container data).
   */
  /* package */ final class StartOffsetExtractorInput extends ForwardingExtractorInput {
  
    private final long startOffset;
  
    /**
     * Creates a new wrapper reading from the given start byte offset.
     *
     * @param input The extractor input to wrap. The reading position must be at or after the start
     *     offset, otherwise data could be read from before the start offset.
     * @param startOffset The offset from which this extractor input provides data, in bytes.
     * @throws IllegalArgumentException Thrown if the start offset is before the current reading
     *     position.
     */
    public StartOffsetExtractorInput(ExtractorInput input, long startOffset) {
      super(input);
      checkArgument(input.getPosition() >= startOffset);
      this.startOffset = startOffset;
    }
  
    @Override
    public long getPosition() {
      return super.getPosition() - startOffset;
    }
  
    @Override
    public long getPeekPosition() {
      return super.getPeekPosition() - startOffset;
    }
  
    @Override
    public long getLength() {
      return super.getLength() - startOffset;
    }
  
    @Override
    public <E extends Throwable> void setRetryPosition(long position, E e) throws E {
      super.setRetryPosition(position + startOffset, e);
    }
  }
  