Make seekTo(currentPosition) a no-op in ExoPlayer.

- Also avoid boxing when passing the seek position to the background
  thread.

Issue: #654

library/src/androidTest/java/com/google/android/exoplayer/util/UtilTest.java

@@ -144,4 +144,21 @@ public class UtilTest extends TestCase {
     assertEquals(1407322800000L, Util.parseXsDateTime("2014-08-06T11:00:00Z"));
   }
 
+  public void testLongSplitting() {
+    assertLongSplittingForValue(Long.MIN_VALUE);
+    assertLongSplittingForValue(Long.MIN_VALUE + 1);
+    assertLongSplittingForValue(-1);
+    assertLongSplittingForValue(0);
+    assertLongSplittingForValue(1);
+    assertLongSplittingForValue(Long.MAX_VALUE - 1);
+    assertLongSplittingForValue(Long.MAX_VALUE);
+  }
+
+  private static void assertLongSplittingForValue(long value) {
+    int topBits = Util.getTopInt(value);
+    int bottomBots = Util.getBottomInt(value);
+    long reconstructedValue = Util.getLong(topBits, bottomBots);
+    assertEquals(value, reconstructedValue);
+  }
+
 }

library/src/main/java/com/google/android/exoplayer/ExoPlayerImplInternal.java

@@ -19,6 +19,7 @@ import com.google.android.exoplayer.ExoPlayer.ExoPlayerComponent;
 import com.google.android.exoplayer.util.Assertions;
 import com.google.android.exoplayer.util.PriorityHandlerThread;
 import com.google.android.exoplayer.util.TraceUtil;
+import com.google.android.exoplayer.util.Util;
 
 import android.os.Handler;
 import android.os.HandlerThread;
@@ -137,7 +138,8 @@ import java.util.List;
   }
 
   public void seekTo(long positionMs) {
-    handler.obtainMessage(MSG_SEEK_TO, positionMs).sendToTarget();
+    handler.obtainMessage(MSG_SEEK_TO, Util.getTopInt(positionMs),
+        Util.getBottomInt(positionMs)).sendToTarget();
   }
 
   public void stop() {
@@ -206,7 +208,7 @@ import java.util.List;
           return true;
         }
         case MSG_SEEK_TO: {
-          seekToInternal((Long) msg.obj);
+          seekToInternal(Util.getLong(msg.arg1, msg.arg2));
           return true;
         }
         case MSG_STOP: {
@@ -482,8 +484,13 @@ import java.util.List;
   }
 
   private void seekToInternal(long positionMs) throws ExoPlaybackException {
+    if (positionMs == (positionUs / 1000)) {
+      // Seek is to the current position. Do nothing.
+      return;
+    }
+
     rebuffering = false;
-    positionUs = positionMs * 1000L;
+    positionUs = positionMs * 1000;
     standaloneMediaClock.stop();
     standaloneMediaClock.setPositionUs(positionUs);
     if (state == ExoPlayer.STATE_IDLE || state == ExoPlayer.STATE_PREPARING) {

library/src/main/java/com/google/android/exoplayer/util/Util.java

@@ -569,6 +569,27 @@ public final class Util {
   }
 
   /**
+   * Returns the top 32 bits of a long as an integer.
+   */
+  public static int getTopInt(long value) {
+    return (int) (value >>> 32);
+  }
+
+  /**
+   * Returns the bottom 32 bits of a long as an integer.
+   */
+  public static int getBottomInt(long value) {
+    return (int) value;
+  }
+
+  /**
+   * Returns a long created by concatenating the bits of two integers.
+   */
+  public static long getLong(int topInteger, int bottomInteger) {
+    return ((long) topInteger << 32) | (bottomInteger & 0xFFFFFFFFL);
+  }
+
+  /**
    * Returns a hex string representation of the data provided.
    *
    * @param data The byte array containing the data to be turned into a hex string.