1 files changed, 149 insertions, 0 deletions
diff --git a/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/source/IcyDataSource.java b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/source/IcyDataSource.java
new file mode 100644
index 0000000000..b35525743a
--- /dev/null
+++ b/mobile/android/exoplayer2/src/main/java/org/mozilla/thirdparty/com/google/android/exoplayer2/source/IcyDataSource.java
@@ -0,0 +1,149 @@
+/*
+ * Copyright (C) 2018 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 org.mozilla.thirdparty.com.google.android.exoplayer2.source;
+
+import android.net.Uri;
+import androidx.annotation.Nullable;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.C;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSource;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.DataSpec;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.upstream.TransferListener;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.Assertions;
+import org.mozilla.thirdparty.com.google.android.exoplayer2.util.ParsableByteArray;
+import java.io.IOException;
+import java.util.List;
+import java.util.Map;
+
+/**
+ * Splits ICY stream metadata out from a stream.
+ *
+ * <p>Note: {@link #open(DataSpec)} and {@link #close()} are not supported. This implementation is
+ * intended to wrap upstream {@link DataSource} instances that are opened and closed directly.
+ */
+/* package */ final class IcyDataSource implements DataSource {
+
+  public interface Listener {
+
+    /**
+     * Called when ICY stream metadata has been split from the stream.
+     *
+     * @param metadata The stream metadata in binary form.
+     */
+    void onIcyMetadata(ParsableByteArray metadata);
+  }
+
+  private final DataSource upstream;
+  private final int metadataIntervalBytes;
+  private final Listener listener;
+  private final byte[] metadataLengthByteHolder;
+  private int bytesUntilMetadata;
+
+  /**
+   * @param upstream The upstream {@link DataSource}.
+   * @param metadataIntervalBytes The interval between ICY stream metadata, in bytes.
+   * @param listener A listener to which stream metadata is delivered.
+   */
+  public IcyDataSource(DataSource upstream, int metadataIntervalBytes, Listener listener) {
+    Assertions.checkArgument(metadataIntervalBytes > 0);
+    this.upstream = upstream;
+    this.metadataIntervalBytes = metadataIntervalBytes;
+    this.listener = listener;
+    metadataLengthByteHolder = new byte[1];
+    bytesUntilMetadata = metadataIntervalBytes;
+  }
+
+  @Override
+  public void addTransferListener(TransferListener transferListener) {
+    upstream.addTransferListener(transferListener);
+  }
+
+  @Override
+  public long open(DataSpec dataSpec) throws IOException {
+    throw new UnsupportedOperationException();
+  }
+
+  @Override
+  public int read(byte[] buffer, int offset, int readLength) throws IOException {
+    if (bytesUntilMetadata == 0) {
+      if (readMetadata()) {
+        bytesUntilMetadata = metadataIntervalBytes;
+      } else {
+        return C.RESULT_END_OF_INPUT;
+      }
+    }
+    int bytesRead = upstream.read(buffer, offset, Math.min(bytesUntilMetadata, readLength));
+    if (bytesRead != C.RESULT_END_OF_INPUT) {
+      bytesUntilMetadata -= bytesRead;
+    }
+    return bytesRead;
+  }
+
+  @Nullable
+  @Override
+  public Uri getUri() {
+    return upstream.getUri();
+  }
+
+  @Override
+  public Map<String, List<String>> getResponseHeaders() {
+    return upstream.getResponseHeaders();
+  }
+
+  @Override
+  public void close() throws IOException {
+    throw new UnsupportedOperationException();
+  }
+
+  /**
+   * Reads an ICY stream metadata block, passing it to {@link #listener} unless the block is empty.
+   *
+   * @return True if the block was extracted, including if its length byte indicated a length of
+   *     zero. False if the end of the stream was reached.
+   * @throws IOException If an error occurs reading from the wrapped {@link DataSource}.
+   */
+  private boolean readMetadata() throws IOException {
+    int bytesRead = upstream.read(metadataLengthByteHolder, 0, 1);
+    if (bytesRead == C.RESULT_END_OF_INPUT) {
+      return false;
+    }
+    int metadataLength = (metadataLengthByteHolder[0] & 0xFF) << 4;
+    if (metadataLength == 0) {
+      return true;
+    }
+
+    int offset = 0;
+    int lengthRemaining = metadataLength;
+    byte[] metadata = new byte[metadataLength];
+    while (lengthRemaining > 0) {
+      bytesRead = upstream.read(metadata, offset, lengthRemaining);
+      if (bytesRead == C.RESULT_END_OF_INPUT) {
+        return false;
+      }
+      offset += bytesRead;
+      lengthRemaining -= bytesRead;
+    }
+
+    // Discard trailing zero bytes.
+    while (metadataLength > 0 && metadata[metadataLength - 1] == 0) {
+      metadataLength--;
+    }
+
+    if (metadataLength > 0) {
+      listener.onIcyMetadata(new ParsableByteArray(metadata, metadataLength));
+    }
+    return true;
+  }
+}