Adding a 64 bit alignment calcualtion to LibYuv.

BUG=

Review URL: https://webrtc-codereview.appspot.com/823006

git-svn-id: http://webrtc.googlecode.com/svn/trunk@2800 4adac7df-926f-26a2-2b94-8c16560cd09d

src/common_video/libyuv/include/webrtc_libyuv.h

@@ -56,13 +56,19 @@ enum VideoRotationMode {
   kRotate270 = 270,
 };
 
+// Align value to 64 bits.
+// Input:
+//   - value   : Input value to be aligned.
+// Return value: An aligned to 64 bit form of the input value.
+int AlignTo64Bit(int value);
+
 // Calculate the required buffer size.
 // Input:
-//   - type - The type of the designated video frame.
-//   - width - frame width in pixels.
-//   - height - frame height in pixels.
-// Return value:  The required size in bytes to accommodate the specified
-//                video frame or -1 in case of an error .
+//   - type         :The type of the designated video frame.
+//   - width        :frame width in pixels.
+//   - height       :frame height in pixels.
+// Return value:    :The required size in bytes to accommodate the specified
+//                   video frame or -1 in case of an error .
 int CalcBufferSize(VideoType type, int width, int height);
 
 // Convert To I420

src/common_video/libyuv/libyuv_unittest.cc

@@ -301,4 +301,16 @@ TEST_F(TestLibYuv, DISABLED_MirrorTest) {
   delete [] test_frame2;
 }
 
+TEST_F(TestLibYuv, alignment) {
+  int value = 640;
+  int aligned_value = (value + 63) & ~63;
+  EXPECT_EQ(AlignTo64Bit(value), aligned_value);
+  value = 600;
+  aligned_value = (value + 63) & ~63;
+  EXPECT_EQ(AlignTo64Bit(value), aligned_value);
+  value = 0;
+  aligned_value = (value + 63) & ~63;
+  EXPECT_EQ(AlignTo64Bit(value), aligned_value);
+}
+
 }  // namespace

src/common_video/libyuv/webrtc_libyuv.cc

@@ -52,6 +52,10 @@ VideoType RawVideoTypeToCommonVideoVideoType(RawVideoType type) {
   return kUnknown;
 }
 
+int AlignTo64Bit(int value) {
+  return ((value + 63) & ~63);
+}
+
 int CalcBufferSize(VideoType type, int width, int height) {
   int buffer_size = 0;
   switch (type) {