content: /*
   * Copyright (C) 2012 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 android.media;
  
  import java.io.Closeable;
  import java.io.IOException;
  
  /**
   * For supplying media data to the framework. Implement this if your app has
   * special requirements for the way media data is obtained.
   *
   * <p class="note">Methods of this interface may be called on multiple different
   * threads. There will be a thread synchronization point between each call to ensure that
   * modifications to the state of your MediaDataSource are visible to future calls. This means
   * you don't need to do your own synchronization unless you're modifying the
   * MediaDataSource from another thread while it's being used by the framework.</p>
   */
  public abstract class MediaDataSource implements Closeable {
      /**
       * Called to request data from the given position.
       *
       * Implementations should fill {@code buffer} with up to {@code size}
       * bytes of data, and return the number of valid bytes in the buffer.
       *
       * Return {@code 0} if size is zero (thus no bytes are read).
       *
       * Return {@code -1} to indicate that end of stream is reached.
       *
       * @param position the position in the data source to read from.
       * @param buffer the buffer to read the data into.
       * @param offset the offset within buffer to read the data into.
       * @param size the number of bytes to read.
       * @throws IOException on fatal errors.
       * @return the number of bytes read, or -1 if end of stream is reached.
       */
      public abstract int readAt(long position, byte[] buffer, int offset, int size)
              throws IOException;
  
      /**
       * Called to get the size of the data source.
       *
       * @throws IOException on fatal errors
       * @return the size of data source in bytes, or -1 if the size is unknown.
       */
      public abstract long getSize() throws IOException;
  }
  