Factor out UnPreMultiplyPreservingByteOrder

src/ports/SkImageDecoder_CG.cpp

 /*
  * Copyright 2008 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCGUtils.h"
 #include "SkColorPriv.h"
 #include "SkImageDecoder.h"
@@ skipping 32 matching lines @@
     CGImageSourceRef imageSrc = CGImageSourceCreateWithDataProvider(data, 0);
     CGDataProviderRelease(data);
     return imageSrc;
 }
 
 class SkImageDecoder_CG : public SkImageDecoder {
 protected:
     virtual bool onDecode(SkStream* stream, SkBitmap* bm, Mode);
 };
 
-// Returns an unpremultiplied version of color. It will have the same ordering and size as an
-// SkPMColor, but the alpha will not be premultiplied.
-static SkPMColor unpremultiply_pmcolor(SkPMColor color) {
-    U8CPU a = SkGetPackedA32(color);
-    const SkUnPreMultiply::Scale scale = SkUnPreMultiply::GetScale(a);
-    return SkPackARGB32NoCheck(a,
-                               SkUnPreMultiply::ApplyScale(scale, SkGetPackedR32(color)),
-                               SkUnPreMultiply::ApplyScale(scale, SkGetPackedG32(color)),
-                               SkUnPreMultiply::ApplyScale(scale, SkGetPackedB32(color)));
-}
-
 #define BITMAP_INFO (kCGBitmapByteOrder32Big | kCGImageAlphaPremultipliedLast)
 
 bool SkImageDecoder_CG::onDecode(SkStream* stream, SkBitmap* bm, Mode mode) {
     CGImageSourceRef imageSrc = SkStreamToCGImageSource(stream);
 
     if (NULL == imageSrc) {
         return false;
     }
     SkAutoTCallVProc<const void, CFRelease> arsrc(imageSrc);
 
@@ skipping 37 matching lines @@
             if (SkBitmap::ComputeIsOpaque(*bm)) {
                 bm->setAlphaType(kOpaque_SkAlphaType);
             }
     }
     if (!bm->isOpaque() && this->getRequireUnpremultipliedColors()) {
         // CGBitmapContext does not support unpremultiplied, so the image has been premultiplied.
         // Convert to unpremultiplied.
         for (int i = 0; i < width; ++i) {
             for (int j = 0; j < height; ++j) {
                 uint32_t* addr = bm->getAddr32(i, j);
-                *addr = unpremultiply_pmcolor(*addr);
+                *addr = SkUnPreMultiply::UnPreMultiplyPreservingByteOrder(*addr);
             }
         }
         bm->setAlphaType(kUnpremul_SkAlphaType);
     }
     bm->unlockPixels();
     return true;
 }
 
 ///////////////////////////////////////////////////////////////////////////////
 
@@ skipping 165 matching lines @@
 
     SkAutoTCallVProc<const void, CFRelease> arsrc(imageSrc);
     const CFStringRef name = CGImageSourceGetType(imageSrc);
     if (NULL == name) {
         return SkImageDecoder::kUnknown_Format;
     }
     return UTType_to_Format(name);
 }
 
 static SkImageDecoder_FormatReg gFormatReg(get_format_cg);