Adding png scanline decoding to kIndex8

src/codec/SkCodec_libbmp.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCodec_libbmp.h"
 #include "SkCodecPriv.h"
 #include "SkColorPriv.h"
 #include "SkStream.h"
-#include "SkUtils.h"
 
 /*
  *
  * Checks if the conversion between the input image and the requested output
  * image has been implemented
  *
  */
 static bool conversion_possible(const SkImageInfo& dst,
                                 const SkImageInfo& src) {
     // Ensure that the profile type is unchanged
@@ skipping 573 matching lines @@
     }
 
     // Create the color table if necessary and prepare the stream for decode
     // Note that if it is non-NULL, inputColorCount will be modified
     if (!createColorTable(dstInfo.alphaType(), inputColorCount)) {
         SkCodecPrintf("Error: could not create color table.\n");
         return kInvalidInput;
     }
 
     // Copy the color table to the client if necessary
-    if (kIndex_8_SkColorType == dstInfo.colorType()) {
-        SkASSERT(NULL != inputColorPtr);
-        SkASSERT(NULL != inputColorCount);
-        SkASSERT(NULL != fColorTable.get());
-        sk_memcpy32(inputColorPtr, fColorTable->readColors(), *inputColorCount);
-    }
+    copy_color_table(dstInfo, fColorTable, inputColorPtr, inputColorCount);
 
     // Perform the decode
     switch (fInputFormat) {
         case kBitMask_BitmapInputFormat:
             return decodeMask(dstInfo, dst, dstRowBytes, opts);
         case kRLE_BitmapInputFormat:
             return decodeRLE(dstInfo, dst, dstRowBytes, opts);
         case kStandard_BitmapInputFormat:
             return decode(dstInfo, dst, dstRowBytes, opts);
         default:
@@ skipping 15 matching lines @@
     if (fBitsPerPixel <= 8) {
         // Zero is a default for maxColors
         // Also set fNumColors to maxColors when it is too large
         maxColors = 1 << fBitsPerPixel;
         if (fNumColors == 0 || fNumColors >= maxColors) {
             fNumColors = maxColors;
         }
 
         // Inform the caller of the number of colors
         if (NULL != numColors) {
-            SkASSERT(256 == *numColors);
             // We set the number of colors to maxColors in order to ensure
             // safe memory accesses.  Otherwise, an invalid pixel could
             // access memory outside of our color table array.
             *numColors = maxColors;
         }
 
         // Read the color table from the stream
         colorBytes = fNumColors * fBytesPerColor;
         SkAutoTDeleteArray<uint8_t> cBuffer(SkNEW_ARRAY(uint8_t, colorBytes));
         if (stream()->read(cBuffer.get(), colorBytes) != colorBytes) {
@@ skipping 571 matching lines @@
                 uint32_t alphaBit =
                         (srcBuffer.get()[quotient] >> shift) & 0x1;
                 dstRow[x] &= alphaBit - 1;
             }
         }
     }
 
     // Finished decoding the entire image
     return kSuccess;
 }