remoting: Extract the utility to get the BytesPerPixel from PixelFormat into a function.

Note: That was a TODO for hclam.

BUG=None
TEST=trybots

Review URL: http://codereview.chromium.org/2865019

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@50928 0039d316-1c4b-4281-b951-d872f2087c98

remoting/base/protocol_util.cc

@@ -24,4 +24,19 @@ scoped_refptr<media::DataBuffer> SerializeAndFrameMessage(
   return buffer;
 }
 
+int GetBytesPerPixel(PixelFormat format) {
+  // Note: The order is important here for performace. This is sorted from the
+  // most common to the less common (PixelFormatAscii is mostly used
+  // just for testing).
+  switch (format) {
+    case PixelFormatRgb24:  return 3;
+    case PixelFormatRgb565: return 2;
+    case PixelFormatRgb32:  return 4;
+    case PixelFormatAscii:  return 1;
+    default:
+      NOTREACHED() << "Pixel format not supported";
+      return 0;
+  }
+}
+
 }  // namespace remoting

remoting/base/protocol_util.h

@@ -7,6 +7,7 @@
 
 #include "google/protobuf/message_lite.h"
 #include "media/base/data_buffer.h"
+#include "remoting/base/protocol/chromotocol.pb.h"
 
 // This file defines utility methods used for encoding and decoding the protocol
 // used in Chromoting.
@@ -19,6 +20,8 @@ namespace remoting {
 scoped_refptr<media::DataBuffer> SerializeAndFrameMessage(
     const google::protobuf::MessageLite& msg);
 
+int GetBytesPerPixel(PixelFormat format);
+
 }  // namespace remoting
 
 #endif  // REMOTING_BASE_PROTOCOL_UTIL_H_

remoting/client/decoder_verbatim.cc

@@ -4,6 +4,8 @@
 
 #include "remoting/client/decoder_verbatim.h"
 
+#include "remoting/base/protocol_util.h"
+
 namespace remoting {
 
 DecoderVerbatim::DecoderVerbatim()
@@ -37,20 +39,6 @@ bool DecoderVerbatim::PartialDecode(HostMessage* message) {
   int y = message->update_stream_packet().header().y();
   PixelFormat pixel_format =
       message->update_stream_packet().header().pixel_format();
-  int bytes_per_pixel = 0;
-
-  // TODO(hclam): Extract the following to an util function.
-  if (pixel_format == PixelFormatRgb24) {
-    bytes_per_pixel = 3;
-  } else if (pixel_format == PixelFormatRgb565) {
-    bytes_per_pixel = 2;
-  } else if (pixel_format == PixelFormatRgb32) {
-    bytes_per_pixel = 4;
-  } else if (pixel_format == PixelFormatAscii) {
-    bytes_per_pixel = 1;
-  } else {
-    NOTREACHED() << "Pixel format not supported";
-  }
 
   if (static_cast<PixelFormat>(frame_->format()) != pixel_format) {
     NOTREACHED() << "Pixel format of message doesn't match the video frame. "
@@ -59,6 +47,7 @@ bool DecoderVerbatim::PartialDecode(HostMessage* message) {
                  << " Color space conversion required.";
   }
 
+  int bytes_per_pixel = GetBytesPerPixel(pixel_format);
   // Copy the data line by line.
   const int src_stride = bytes_per_pixel * width;
   const char* src = message->update_stream_packet().data().c_str();