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.source;
  
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.FormatHolder;
  import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
  import java.io.IOException;
  
  /**
   * A stream of media samples (and associated format information).
   */
  public interface SampleStream {
  
    /**
     * Returns whether data is available to be read.
     * <p>
     * Note: If the stream has ended then a buffer with the end of stream flag can always be read from
     * {@link #readData(FormatHolder, DecoderInputBuffer, boolean)}. Hence an ended stream is always
     * ready.
     *
     * @return Whether data is available to be read.
     */
    boolean isReady();
  
    /**
     * Throws an error that's preventing data from being read. Does nothing if no such error exists.
     *
     * @throws IOException The underlying error.
     */
    void maybeThrowError() throws IOException;
  
    /**
     * Attempts to read from the stream.
     * <p>
     * If the stream has ended then {@link C#BUFFER_FLAG_END_OF_STREAM} flag is set on {@code buffer}
     * and {@link C#RESULT_BUFFER_READ} is returned. Else if no data is available then
     * {@link C#RESULT_NOTHING_READ} is returned. Else if the format of the media is changing or if
     * {@code formatRequired} is set then {@code formatHolder} is populated and
     * {@link C#RESULT_FORMAT_READ} is returned. Else {@code buffer} is populated and
     * {@link C#RESULT_BUFFER_READ} is returned.
     *
     * @param formatHolder A {@link FormatHolder} to populate in the case of reading a format.
     * @param buffer A {@link DecoderInputBuffer} to populate in the case of reading a sample or the
     *     end of the stream. If the end of the stream has been reached, the
     *     {@link C#BUFFER_FLAG_END_OF_STREAM} flag will be set on the buffer.
     * @param formatRequired Whether the caller requires that the format of the stream be read even if
     *     it's not changing. A sample will never be read if set to true, however it is still possible
     *     for the end of stream or nothing to be read.
     * @return The result, which can be {@link C#RESULT_NOTHING_READ}, {@link C#RESULT_FORMAT_READ} or
     *     {@link C#RESULT_BUFFER_READ}.
     */
    int readData(FormatHolder formatHolder, DecoderInputBuffer buffer, boolean formatRequired);
  
    /**
     * Attempts to skip to the keyframe before the specified position, or to the end of the stream if
     * {@code positionUs} is beyond it.
     *
     * @param positionUs The specified time.
     * @return The number of samples that were skipped.
     */
    int skipData(long positionUs);
  
  }
  