Merge pull request #408 from dnutcracker/dev

fix for issue #403

library/src/main/java/com/google/android/exoplayer/upstream/AssetDataSource.java

+/*
+ * Copyright (C) 2014 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.exoplayer.upstream;
+
+import java.io.EOFException;
+import java.io.IOException;
+import java.io.InputStream;
+
+import android.content.res.AssetManager;
+import android.util.Log;
+
+import com.google.android.exoplayer.C;
+import com.google.android.exoplayer.upstream.FileDataSource.FileDataSourceException;
+
+/**
+ * A local asset {@link DataSource}.
+ */
+public final class AssetDataSource implements DataSource {
+
+  /**
+   * Thrown when IOException is encountered during local asset read operation.
+   */
+  public static class AssetDataSourceException extends IOException {
+
+    public AssetDataSourceException(IOException cause) {
+      super(cause);
+    }
+
+  }
+
+  private final TransferListener listener;
+
+  private InputStream assetInputStream;
+  private AssetManager assetManager;
+  private long bytesRemaining;
+  private boolean opened;
+
+  /**
+   * Constructs a new {@link DataSource} that retrieves data from a local asset.
+   */
+  public AssetDataSource(AssetManager assetManager) {
+	  this(assetManager, null);
+  }
+
+  /**
+   * Constructs a new {@link DataSource} that retrieves data from a local asset.
+   *
+   * @param listener An optional listener. Specify {@code null} for no listener.
+   */
+  public AssetDataSource(AssetManager assetManager, TransferListener listener) {
+    this.assetManager = assetManager;
+    this.listener = listener;
+  }
+
+  @Override
+  public long open(DataSpec dataSpec) throws AssetDataSourceException {
+    try {
+      // Lose the '/' prefix in the path or else AssetManager won't find our file
+      assetInputStream = assetManager.open(dataSpec.uri.getPath().substring(1), AssetManager.ACCESS_RANDOM);
+      assetInputStream.skip(dataSpec.position);
+      bytesRemaining = dataSpec.length == C.LENGTH_UNBOUNDED ? assetInputStream.available()
+          : dataSpec.length;
+      if (bytesRemaining < 0) {
+        throw new EOFException();
+      }
+    } catch (IOException e) {
+      throw new AssetDataSourceException(e);
+    }
+
+    opened = true;
+    if (listener != null) {
+      listener.onTransferStart();
+    }
+    return bytesRemaining;
+  }
+
+  @Override
+  public int read(byte[] buffer, int offset, int readLength) throws AssetDataSourceException {
+    if (bytesRemaining == 0) {
+      return -1;
+    } else {
+      int bytesRead = 0;
+      try {
+        bytesRead = assetInputStream.read(buffer, offset, (int) Math.min(bytesRemaining, readLength));
+      } catch (IOException e) {
+        throw new AssetDataSourceException(e);
+      }
+
+      if (bytesRead > 0) {
+        bytesRemaining -= bytesRead;
+        if (listener != null) {
+          listener.onBytesTransferred(bytesRead);
+        }
+      }
+
+      return bytesRead;
+    }
+  }
+
+  @Override
+  public void close() throws AssetDataSourceException {
+    if (assetInputStream != null) {
+      try {
+    	  assetInputStream.close();
+      } catch (IOException e) {
+        throw new AssetDataSourceException(e);
+      } finally {
+    	  assetInputStream = null;
+
+        if (opened) {
+          opened = false;
+          if (listener != null) {
+            listener.onTransferEnd();
+          }
+        }
+      }
+    }
+  }
+
+}