diff -r 000000000000 -r 6474c204b198 image/decoders/nsBMPDecoder.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/image/decoders/nsBMPDecoder.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,135 @@
+/* vim:set tw=80 expandtab softtabstop=4 ts=4 sw=4: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+
+#ifndef _nsBMPDecoder_h
+#define _nsBMPDecoder_h
+
+#include "nsAutoPtr.h"
+#include "gfxColor.h"
+#include "Decoder.h"
+#include "BMPFileHeaders.h"
+
+namespace mozilla {
+namespace image {
+
+class RasterImage;
+
+/**
+ * Decoder for BMP-Files, as used by Windows and OS/2
+ */
+class nsBMPDecoder : public Decoder
+{
+public:
+
+    nsBMPDecoder(RasterImage &aImage);
+    ~nsBMPDecoder();
+
+    // Specifies whether or not the BMP file will contain alpha data
+    // If set to true and the BMP is 32BPP, the alpha data will be
+    // retrieved from the 4th byte of image data per pixel 
+    void SetUseAlphaData(bool useAlphaData);
+    // Obtains the bits per pixel from the internal BIH header
+    int32_t GetBitsPerPixel() const;
+    // Obtains the width from the internal BIH header
+    int32_t GetWidth() const;
+    // Obtains the abs-value of the height from the internal BIH header
+    int32_t GetHeight() const;
+    // Obtains the internal output image buffer
+    uint32_t* GetImageData();
+    // Obtains the size of the compressed image resource
+    int32_t GetCompressedImageSize() const;
+    // Obtains whether or not a BMP file had alpha data in its 4th byte
+    // for 32BPP bitmaps.  Only use after the bitmap has been processed.
+    bool HasAlphaData() const;
+
+    virtual void WriteInternal(const char* aBuffer, uint32_t aCount, DecodeStrategy aStrategy);
+    virtual void FinishInternal();
+
+private:
+
+    /** Calculates the red-, green- and blueshift in mBitFields using
+     * the bitmasks from mBitFields */
+    NS_METHOD CalcBitShift();
+
+    uint32_t mPos;
+
+    BMPFILEHEADER mBFH;
+    BITMAPV5HEADER mBIH;
+    char mRawBuf[WIN_V3_INTERNAL_BIH_LENGTH];
+
+    uint32_t mLOH; ///< Length of the header
+
+    uint32_t mNumColors; ///< The number of used colors, i.e. the number of entries in mColors
+    colorTable *mColors;
+
+    bitFields mBitFields;
+
+    uint8_t *mRow;      ///< Holds one raw line of the image
+    uint32_t mRowBytes; ///< How many bytes of the row were already received
+    int32_t mCurLine;   ///< Index of the line of the image that's currently being decoded: [height,1]
+    int32_t mOldLine;   ///< Previous index of the line 
+    int32_t mCurPos;    ///< Index in the current line of the image
+
+    ERLEState mState;   ///< Maintains the current state of the RLE decoding
+    uint32_t mStateData;///< Decoding information that is needed depending on mState
+
+    /** Set mBFH from the raw data in mRawBuf, converting from little-endian
+     * data to native data as necessary */
+    void ProcessFileHeader();
+    /** Set mBIH from the raw data in mRawBuf, converting from little-endian
+     * data to native data as necessary */
+    void ProcessInfoHeader();
+
+    // Stores whether the image data may store alpha data, or if
+    // the alpha data is unspecified and filled with a padding byte of 0. 
+    // When a 32BPP bitmap is stored in an ICO or CUR file, its 4th byte
+    // is used for alpha transparency.  When it is stored in a BMP, its
+    // 4th byte is reserved and is always 0.
+    // Reference: 
+    // http://en.wikipedia.org/wiki/ICO_(file_format)#cite_note-9
+    // Bitmaps where the alpha bytes are all 0 should be fully visible.
+    bool mUseAlphaData;
+    // Whether the 4th byte alpha data was found to be non zero and hence used.
+    bool mHaveAlphaData;
+};
+
+/** Sets the pixel data in aDecoded to the given values.
+ * @param aDecoded pointer to pixel to be set, will be incremented to point to the next pixel.
+ */
+static inline void SetPixel(uint32_t*& aDecoded, uint8_t aRed, uint8_t aGreen, uint8_t aBlue, uint8_t aAlpha = 0xFF)
+{
+    *aDecoded++ = gfxPackedPixel(aAlpha, aRed, aGreen, aBlue);
+}
+
+static inline void SetPixel(uint32_t*& aDecoded, uint8_t idx, colorTable* aColors)
+{
+    SetPixel(aDecoded, aColors[idx].red, aColors[idx].green, aColors[idx].blue);
+}
+
+/** Sets two (or one if aCount = 1) pixels
+ * @param aDecoded where the data is stored. Will be moved 4 resp 8 bytes
+ * depending on whether one or two pixels are written.
+ * @param aData The values for the two pixels
+ * @param aCount Current count. Is decremented by one or two.
+ */
+inline void Set4BitPixel(uint32_t*& aDecoded, uint8_t aData,
+                         uint32_t& aCount, colorTable* aColors)
+{
+    uint8_t idx = aData >> 4;
+    SetPixel(aDecoded, idx, aColors);
+    if (--aCount > 0) {
+        idx = aData & 0xF;
+        SetPixel(aDecoded, idx, aColors);
+        --aCount;
+    }
+}
+
+} // namespace image
+} // namespace mozilla
+
+
+#endif
+