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 static java.lang.annotation.ElementType.TYPE_USE;
  
  import androidx.annotation.IntDef;
  import com.google.android.exoplayer2.C;
  import com.google.android.exoplayer2.FormatHolder;
  import com.google.android.exoplayer2.decoder.DecoderInputBuffer;
  import com.google.android.exoplayer2.decoder.DecoderInputBuffer.InsufficientCapacityException;
  import java.io.IOException;
  import java.lang.annotation.Documented;
  import java.lang.annotation.Retention;
  import java.lang.annotation.RetentionPolicy;
  import java.lang.annotation.Target;
  
  /** A stream of media samples (and associated format information). */
  public interface SampleStream {
  
    /**
     * Flags that can be specified when calling {@link #readData}. Possible flag values are {@link
     * #FLAG_PEEK}, {@link #FLAG_REQUIRE_FORMAT} and {@link #FLAG_OMIT_SAMPLE_DATA}.
     */
    @Documented
    @Retention(RetentionPolicy.SOURCE)
    @Target(TYPE_USE)
    @IntDef(
        flag = true,
        value = {FLAG_PEEK, FLAG_REQUIRE_FORMAT, FLAG_OMIT_SAMPLE_DATA})
    @interface ReadFlags {}
    /** Specifies that the read position should not be advanced if a sample buffer is read. */
    int FLAG_PEEK = 1;
    /**
     * Specifies that if a sample buffer would normally be read next, the format of the stream should
     * be read instead. In detail, the effect of this flag is as follows:
     *
     * <ul>
     *   <li>If a sample buffer would be read were the flag not set, then the stream format will be
     *       read instead.
     *   <li>If nothing would be read were the flag not set, then the stream format will be read if
     *       it's known. If the stream format is not known then behavior is unchanged.
     *   <li>If an end of stream buffer would be read were the flag not set, then behavior is
     *       unchanged.
     * </ul>
     */
    int FLAG_REQUIRE_FORMAT = 1 << 1;
    /**
     * Specifies that {@link DecoderInputBuffer#data}, {@link DecoderInputBuffer#supplementalData} and
     * {@link DecoderInputBuffer#cryptoInfo} should not be populated when reading a sample buffer.
     *
     * <p>This flag is useful for efficiently reading or (when combined with {@link #FLAG_PEEK})
     * peeking sample metadata. It can also be used for efficiency by a caller wishing to skip a
     * sample buffer.
     */
    int FLAG_OMIT_SAMPLE_DATA = 1 << 2;
  
    /** Return values of {@link #readData}. */
    @Documented
    @Retention(RetentionPolicy.SOURCE)
    @Target(TYPE_USE)
    @IntDef({C.RESULT_NOTHING_READ, C.RESULT_FORMAT_READ, C.RESULT_BUFFER_READ})
    @interface ReadDataResult {}
  
    /**
     * 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}. 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 readFlags Flags controlling the behavior of this read operation.
     * @return The {@link ReadDataResult result} of the read operation.
     * @throws InsufficientCapacityException If the {@code buffer} has insufficient capacity to hold
     *     the data of a sample being read. The buffer {@link DecoderInputBuffer#timeUs timestamp} and
     *     flags are populated if this exception is thrown, but the read position is not advanced.
     */
    @ReadDataResult
    int readData(FormatHolder formatHolder, DecoderInputBuffer buffer, @ReadFlags int readFlags);
  
    /**
     * 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);
  }
  