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

remoting/base/protocol_util.cc

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "remoting/base/protocol_util.h"
 
 #include "base/basictypes.h"
 #include "base/hash_tables.h"
 #include "talk/base/byteorder.h"
 
 namespace remoting {
 
 scoped_refptr<media::DataBuffer> SerializeAndFrameMessage(
     const google::protobuf::MessageLite& msg) {
 
   // Create a buffer with 4 extra bytes. This is used as prefix to write an
   // int32 of the serialized message size for framing.
   const int kExtraBytes = sizeof(int32);
   int size = msg.ByteSize() + kExtraBytes;
   scoped_refptr<media::DataBuffer> buffer = new media::DataBuffer(size);
   talk_base::SetBE32(buffer->GetWritableData(), msg.GetCachedSize());
   msg.SerializeWithCachedSizesToArray(buffer->GetWritableData() + kExtraBytes);
   buffer->SetDataSize(size);
   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