Scanline decoding for bmp

src/codec/SkBmpCodec.cpp

Index: src/codec/SkBmpCodec.cpp
diff --git a/src/codec/SkBmpCodec.cpp b/src/codec/SkBmpCodec.cpp
index fa4608ffeec513cacd753fc3efc721497d1eff3c..2b70cb415891d95cf5b2a8f81258e65e5b36b635 100644
--- a/src/codec/SkBmpCodec.cpp
+++ b/src/codec/SkBmpCodec.cpp
@@ -44,16 +44,6 @@ enum BmpCompressionMethod {
 };
 
 /*
- * Used to define the input format of the bmp
- */
-enum BmpInputFormat {
-    kStandard_BmpInputFormat,
-    kRLE_BmpInputFormat,
-    kBitMask_BmpInputFormat,
-    kUnknown_BmpInputFormat
-};
-
-/*
  * Checks the start of the stream to see if the image is a bitmap
  */
 bool SkBmpCodec::IsBmp(SkStream* stream) {
@@ -472,7 +462,7 @@ bool SkBmpCodec::ReadHeader(SkStream* stream, bool inIco, SkCodec** codecOut) {
         switch (inputFormat) {
             case kStandard_BmpInputFormat:
                 *codecOut = SkNEW_ARGS(SkBmpStandardCodec, (imageInfo, stream,
-                        bitsPerPixel, numColors, bytesPerColor,
+                        inputFormat, bitsPerPixel, numColors, bytesPerColor,
                         offset - bytesRead, rowOrder, inIco));
                 return true;
             case kBitMask_BmpInputFormat:
@@ -490,7 +480,7 @@ bool SkBmpCodec::ReadHeader(SkStream* stream, bool inIco, SkCodec** codecOut) {
                 }
 
                 *codecOut = SkNEW_ARGS(SkBmpMaskCodec, (imageInfo, stream,
-                        bitsPerPixel, masks.detach(), rowOrder));
+                        inputFormat, bitsPerPixel, masks.detach(), rowOrder));
                 return true;
             case kRLE_BmpInputFormat:
                 // Bmp-in-Ico must be standard mode
@@ -499,7 +489,7 @@ bool SkBmpCodec::ReadHeader(SkStream* stream, bool inIco, SkCodec** codecOut) {
                 // Icos skip the header that contains totalBytes.
                 SkASSERT(!inIco);
                 *codecOut = SkNEW_ARGS(SkBmpRLECodec, (
-                        imageInfo, stream, bitsPerPixel, numColors,
+                        imageInfo, stream, inputFormat, bitsPerPixel, numColors,
                         bytesPerColor, offset - bytesRead, rowOrder, RLEBytes));
                 return true;
             default:
@@ -529,8 +519,9 @@ SkCodec* SkBmpCodec::NewFromStream(SkStream* stream, bool inIco) {
 }
 
 SkBmpCodec::SkBmpCodec(const SkImageInfo& info, SkStream* stream,
-        uint16_t bitsPerPixel, RowOrder rowOrder)
+        BmpInputFormat inputFormat, uint16_t bitsPerPixel, RowOrder rowOrder)
     : INHERITED(info, stream)
+    , fInputFormat(inputFormat)
     , fBitsPerPixel(bitsPerPixel)
     , fRowOrder(rowOrder)
 {}
@@ -562,3 +553,21 @@ uint32_t SkBmpCodec::computeNumColors(uint32_t numColors) {
     }
     return numColors;
 }
+
+SkScanlineDecoder* SkBmpCodec::NewSDFromStream(SkStream* stream) {
+    SkAutoTDelete<SkBmpCodec> codec(static_cast<SkBmpCodec*>(SkBmpCodec::NewFromStream(stream)));
+    if (!codec) {
+        return NULL;
+    }
+
+    switch(codec->fInputFormat) {
+        case kStandard_BmpInputFormat:
+            return SkNEW_ARGS(SkBmpStandardScanlineDecoder, ((SkBmpStandardCodec*) codec.detach()));
+        case kBitMask_BmpInputFormat:
+            return SkNEW_ARGS(SkBmpMaskScanlineDecoder, ((SkBmpMaskCodec*) codec.detach()));
+        case kRLE_BmpInputFormat:
+            return SkNEW_ARGS(SkBmpRLEScanlineDecoder, ((SkBmpRLECodec*) codec.detach()));
+        default:
+            return NULL;

[scroggo, 2015/08/13 21:25:35]

Can this case be reached?

[msarett, 2015/08/14 15:44:48]

No. Adding an SkASSERT(false).

+    }
+}