Bug 370942 - Remove non-Cairo from jpeg decoder and optimize loop

p=Alfred Kayser <alfredkayser@nl.ibm.com>
r=tor, sr=pavlov

modules/libpr0n/decoders/jpeg/nsJPEGDecoder.cpp

@@ -49,6 +49,7 @@
 #include "ImageLogging.h"
 #include "nsIImage.h"
 #include "nsIInterfaceRequestorUtils.h"
+#include "gfxColor.h"
 
 #include "jerror.h"
 
@@ -470,7 +471,6 @@ nsJPEGDecoder::OutputScanlines()
   PRUint8 *imageData;
   PRUint32 imageDataLength;
   mFrame->GetImageData(&imageData, &imageDataLength);
-  nsCOMPtr<nsIImage> img(do_GetInterface(mFrame));
 
   while ((mInfo.output_scanline < mInfo.output_height)) {
       /* Request one scanline.  Returns 0 or 1 scanlines. */    
@@ -483,16 +483,15 @@ nsJPEGDecoder::OutputScanlines()
       PRUint32 offset = (mInfo.output_scanline - 1) * mInfo.output_width;
       PRUint32 *ptrOutputBuf = ((PRUint32*)imageData) + offset;
       JSAMPLE *j1 = mSamples[0];
-      for (PRUint32 i=0; i < mInfo.output_width; ++i) {
-        PRUint8 r = *j1++;
-        PRUint8 g = *j1++;
-        PRUint8 b = *j1++;
-        *ptrOutputBuf++ = (0xFF << 24) | (r << 16) | (g << 8) | b;
+      for (PRUint32 i=mInfo.output_width; i>0; --i) {
+        *ptrOutputBuf++ = GFX_PACKED_PIXEL(0xFF, j1[0], j1[1], j1[2]);
+        j1+=3;
       }
   }
 
   if (top != mInfo.output_scanline) {
       nsIntRect r(0, top, mInfo.output_width, mInfo.output_scanline-top);
+      nsCOMPtr<nsIImage> img(do_GetInterface(mFrame));
       img->ImageUpdated(nsnull, nsImageUpdateFlags_kBitsChanged, &r);
       mObserver->OnDataAvailable(nsnull, mFrame, &r);
   }