Scanline decoding for bmp

src/codec/SkBmpRLECodec.cpp

Index: src/codec/SkBmpRLECodec.cpp
diff --git a/src/codec/SkBmpRLECodec.cpp b/src/codec/SkBmpRLECodec.cpp
index 14a5b01c1f374d520856058aeef61ef9978324d3..761cd9185d9c1fa1933e941a6cb9a3f381c323f0 100644
--- a/src/codec/SkBmpRLECodec.cpp
+++ b/src/codec/SkBmpRLECodec.cpp
@@ -53,20 +53,9 @@ SkCodec::Result SkBmpRLECodec::onGetPixels(const SkImageInfo& dstInfo,
         return kInvalidConversion;
     }
 
-    // Create the color table if necessary and prepare the stream for decode
-    // Note that if it is non-NULL, inputColorCount will be modified
-    if (!this->createColorTable(inputColorCount)) {
-        SkCodecPrintf("Error: could not create color table.\n");
-        return kInvalidInput;
-    }
-
-    // Copy the color table to the client if necessary
-    copy_color_table(dstInfo, fColorTable, inputColorPtr, inputColorCount);
-
-    // Initialize a swizzler if necessary
-    if (!this->initializeStreamBuffer()) {
-        SkCodecPrintf("Error: cannot initialize swizzler.\n");
-        return kInvalidConversion;
+    Result result = this->prepareToDecode(dstInfo, opts, inputColorPtr, inputColorCount);
+    if (kSuccess != result) {
+        return result;
     }
 
     // Perform the decode
@@ -196,12 +185,7 @@ void SkBmpRLECodec::setPixel(void* dst, size_t dstRowBytes,
                              uint8_t index) {
     // Set the row
     int height = dstInfo.height();
-    int row;
-    if (SkBmpCodec::kBottomUp_RowOrder == this->rowOrder()) {
-        row = height - y - 1;
-    } else {
-        row = y;
-    }
+    int row = this->getDstRow(y);
 
     // Set the pixel based on destination color type
     switch (dstInfo.colorType()) {
@@ -233,12 +217,7 @@ void SkBmpRLECodec::setRGBPixel(void* dst, size_t dstRowBytes,
                                 uint8_t blue) {
     // Set the row
     int height = dstInfo.height();
-    int row;
-    if (SkBmpCodec::kBottomUp_RowOrder == this->rowOrder()) {
-        row = height - y - 1;
-    } else {
-        row = y;
-    }
+    uint32_t row = this->getDstRow(y);
 
     // Set the pixel based on destination color type
     switch (dstInfo.colorType()) {
@@ -456,3 +435,24 @@ SkCodec::Result SkBmpRLECodec::decode(const SkImageInfo& dstInfo,
         }
     }
 }
+
+SkCodec::Result SkBmpRLECodec::prepareToDecode(const SkImageInfo& dstInfo,
+        const SkCodec::Options& options, SkPMColor inputColorPtr[], int* inputColorCount) {
+    // Create the color table if necessary and prepare the stream for decode
+    // Note that if it is non-NULL, inputColorCount will be modified
+    if (!this->createColorTable(inputColorCount)) {
+        SkCodecPrintf("Error: could not create color table.\n");
+        return SkCodec::kInvalidInput;
+    }
+
+    // Copy the color table to the client if necessary
+    copy_color_table(dstInfo, this->fColorTable, inputColorPtr, inputColorCount);
+
+    // Initialize a buffer for encoded RLE data
+    if (!this->initializeStreamBuffer()) {
+        SkCodecPrintf("Error: cannot initialize swizzler.\n");
+        return SkCodec::kInvalidConversion;
+    }
+
+    return SkCodec::kSuccess;
+}