diff -r 000000000000 -r 6474c204b198 image/decoders/nsBMPDecoder.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/image/decoders/nsBMPDecoder.cpp	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,743 @@
+/* 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/. */
+/* I got the format description from http://www.daubnet.com/formats/BMP.html */
+
+/* This is a Cross-Platform BMP Decoder, which should work everywhere, including
+ * Big-Endian machines like the PowerPC. */
+
+#include <stdlib.h>
+
+#include "ImageLogging.h"
+#include "mozilla/Endian.h"
+#include "nsBMPDecoder.h"
+
+#include "nsIInputStream.h"
+#include "RasterImage.h"
+#include <algorithm>
+
+namespace mozilla {
+namespace image {
+
+#ifdef PR_LOGGING
+static PRLogModuleInfo *
+GetBMPLog()
+{
+  static PRLogModuleInfo *sBMPLog;
+  if (!sBMPLog)
+    sBMPLog = PR_NewLogModule("BMPDecoder");
+  return sBMPLog;
+}
+#endif
+
+// Convert from row (1..height) to absolute line (0..height-1)
+#define LINE(row) ((mBIH.height < 0) ? (-mBIH.height - (row)) : ((row) - 1))
+#define PIXEL_OFFSET(row, col) (LINE(row) * mBIH.width + col)
+
+nsBMPDecoder::nsBMPDecoder(RasterImage &aImage)
+ : Decoder(aImage)
+{
+  mColors = nullptr;
+  mRow = nullptr;
+  mCurPos = mPos = mNumColors = mRowBytes = 0;
+  mOldLine = mCurLine = 1; // Otherwise decoder will never start
+  mState = eRLEStateInitial;
+  mStateData = 0;
+  mLOH = WIN_V3_HEADER_LENGTH;
+  mUseAlphaData = mHaveAlphaData = false;
+}
+
+nsBMPDecoder::~nsBMPDecoder()
+{
+  delete[] mColors;
+  if (mRow) {
+      moz_free(mRow);
+  }
+}
+
+// Sets whether or not the BMP will use alpha data
+void 
+nsBMPDecoder::SetUseAlphaData(bool useAlphaData) 
+{
+  mUseAlphaData = useAlphaData;
+}
+
+// Obtains the bits per pixel from the internal BIH header
+int32_t 
+nsBMPDecoder::GetBitsPerPixel() const
+{
+  return mBIH.bpp;
+}
+
+// Obtains the width from the internal BIH header
+int32_t 
+nsBMPDecoder::GetWidth() const
+{
+  return mBIH.width; 
+}
+
+// Obtains the abs-value of the height from the internal BIH header
+int32_t 
+nsBMPDecoder::GetHeight() const
+{
+  return abs(mBIH.height);
+}
+
+// Obtains the internal output image buffer
+uint32_t* 
+nsBMPDecoder::GetImageData() 
+{
+  return reinterpret_cast<uint32_t*>(mImageData);
+}
+
+// Obtains the size of the compressed image resource
+int32_t 
+nsBMPDecoder::GetCompressedImageSize() const
+{
+  // For everything except BI_RGB the header field must be defined
+  if (mBIH.compression != BI_RGB) {
+    return mBIH.image_size;
+  }
+
+  // mBIH.image_size isn't always filled for BI_RGB so calculate it manually
+  // The pixel array size is calculated based on extra 4 byte boundary padding
+  uint32_t rowSize = (mBIH.bpp * mBIH.width + 7) / 8; // + 7 to round up
+  // Pad to DWORD Boundary
+  if (rowSize % 4) {
+    rowSize += (4 - (rowSize % 4));
+  }
+
+  // The height should be the absolute value of what the height is in the BIH.
+  // If positive the bitmap is stored bottom to top, otherwise top to bottom
+  int32_t pixelArraySize = rowSize * GetHeight();
+  return pixelArraySize;
+}
+
+// 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 
+nsBMPDecoder::HasAlphaData() const 
+{
+  return mHaveAlphaData;
+}
+
+
+void
+nsBMPDecoder::FinishInternal()
+{
+    // We shouldn't be called in error cases
+    NS_ABORT_IF_FALSE(!HasError(), "Can't call FinishInternal on error!");
+
+    // We should never make multiple frames
+    NS_ABORT_IF_FALSE(GetFrameCount() <= 1, "Multiple BMP frames?");
+
+    // Send notifications if appropriate
+    if (!IsSizeDecode() && HasSize()) {
+
+        // Invalidate
+        nsIntRect r(0, 0, mBIH.width, GetHeight());
+        PostInvalidation(r);
+
+        if (mUseAlphaData) {
+          PostFrameStop(FrameBlender::kFrameHasAlpha);
+        } else {
+          PostFrameStop(FrameBlender::kFrameOpaque);
+        }
+        PostDecodeDone();
+    }
+}
+
+// ----------------------------------------
+// Actual Data Processing
+// ----------------------------------------
+
+static void calcBitmask(uint32_t aMask, uint8_t& aBegin, uint8_t& aLength)
+{
+    // find the rightmost 1
+    uint8_t pos;
+    bool started = false;
+    aBegin = aLength = 0;
+    for (pos = 0; pos <= 31; pos++) {
+        if (!started && (aMask & (1 << pos))) {
+            aBegin = pos;
+            started = true;
+        }
+        else if (started && !(aMask & (1 << pos))) {
+            aLength = pos - aBegin;
+            break;
+        }
+    }
+}
+
+NS_METHOD nsBMPDecoder::CalcBitShift()
+{
+    uint8_t begin, length;
+    // red
+    calcBitmask(mBitFields.red, begin, length);
+    mBitFields.redRightShift = begin;
+    mBitFields.redLeftShift = 8 - length;
+    // green
+    calcBitmask(mBitFields.green, begin, length);
+    mBitFields.greenRightShift = begin;
+    mBitFields.greenLeftShift = 8 - length;
+    // blue
+    calcBitmask(mBitFields.blue, begin, length);
+    mBitFields.blueRightShift = begin;
+    mBitFields.blueLeftShift = 8 - length;
+    return NS_OK;
+}
+
+void
+nsBMPDecoder::WriteInternal(const char* aBuffer, uint32_t aCount, DecodeStrategy)
+{
+    NS_ABORT_IF_FALSE(!HasError(), "Shouldn't call WriteInternal after error!");
+
+    // aCount=0 means EOF, mCurLine=0 means we're past end of image
+    if (!aCount || !mCurLine)
+        return;
+
+    if (mPos < BFH_INTERNAL_LENGTH) { /* In BITMAPFILEHEADER */
+        uint32_t toCopy = BFH_INTERNAL_LENGTH - mPos;
+        if (toCopy > aCount)
+            toCopy = aCount;
+        memcpy(mRawBuf + mPos, aBuffer, toCopy);
+        mPos += toCopy;
+        aCount -= toCopy;
+        aBuffer += toCopy;
+    }
+    if (mPos == BFH_INTERNAL_LENGTH) {
+        ProcessFileHeader();
+        if (mBFH.signature[0] != 'B' || mBFH.signature[1] != 'M') {
+            PostDataError();
+            return;
+        }
+        if (mBFH.bihsize == OS2_BIH_LENGTH)
+            mLOH = OS2_HEADER_LENGTH;
+    }
+    if (mPos >= BFH_INTERNAL_LENGTH && mPos < mLOH) { /* In BITMAPINFOHEADER */
+        uint32_t toCopy = mLOH - mPos;
+        if (toCopy > aCount)
+            toCopy = aCount;
+        memcpy(mRawBuf + (mPos - BFH_INTERNAL_LENGTH), aBuffer, toCopy);
+        mPos += toCopy;
+        aCount -= toCopy;
+        aBuffer += toCopy;
+    }
+
+    // HasSize is called to ensure that if at this point mPos == mLOH but
+    // we have no data left to process, the next time WriteInternal is called
+    // we won't enter this condition again.
+    if (mPos == mLOH && !HasSize()) {
+        ProcessInfoHeader();
+        PR_LOG(GetBMPLog(), PR_LOG_DEBUG, ("BMP is %lix%lix%lu. compression=%lu\n",
+               mBIH.width, mBIH.height, mBIH.bpp, mBIH.compression));
+        // Verify we support this bit depth
+        if (mBIH.bpp != 1 && mBIH.bpp != 4 && mBIH.bpp != 8 &&
+            mBIH.bpp != 16 && mBIH.bpp != 24 && mBIH.bpp != 32) {
+          PostDataError();
+          return;
+        }
+
+        // BMPs with negative width are invalid
+        // Reject extremely wide images to keep the math sane
+        const int32_t k64KWidth = 0x0000FFFF;
+        if (mBIH.width < 0 || mBIH.width > k64KWidth) {
+            PostDataError();
+            return;
+        }
+
+        if (mBIH.height == INT_MIN) {
+            PostDataError();
+            return;
+        }
+
+        uint32_t real_height = GetHeight();
+
+        // Post our size to the superclass
+        PostSize(mBIH.width, real_height);
+        if (HasError()) {
+          // Setting the size led to an error.
+          return;
+        }
+
+        // We have the size. If we're doing a size decode, we got what
+        // we came for.
+        if (IsSizeDecode())
+            return;
+
+        // We're doing a real decode.
+        mOldLine = mCurLine = real_height;
+
+        if (mBIH.bpp <= 8) {
+            mNumColors = 1 << mBIH.bpp;
+            if (mBIH.colors && mBIH.colors < mNumColors)
+                mNumColors = mBIH.colors;
+
+            // Always allocate 256 even though mNumColors might be smaller
+            mColors = new colorTable[256];
+            memset(mColors, 0, 256 * sizeof(colorTable));
+        }
+        else if (mBIH.compression != BI_BITFIELDS && mBIH.bpp == 16) {
+            // Use default 5-5-5 format
+            mBitFields.red   = 0x7C00;
+            mBitFields.green = 0x03E0;
+            mBitFields.blue  = 0x001F;
+            CalcBitShift();
+        }
+
+        // Make sure we have a valid value for our supported compression modes
+        // before adding the frame
+        if (mBIH.compression != BI_RGB && mBIH.compression != BI_RLE8 && 
+            mBIH.compression != BI_RLE4 && mBIH.compression != BI_BITFIELDS) {
+          PostDataError();
+          return;
+        }
+
+        // If we have RLE4 or RLE8 or BI_ALPHABITFIELDS, then ensure we
+        // have valid BPP values before adding the frame
+        if (mBIH.compression == BI_RLE8 && mBIH.bpp != 8) {
+          PR_LOG(GetBMPLog(), PR_LOG_DEBUG, 
+                 ("BMP RLE8 compression only supports 8 bits per pixel\n"));
+          PostDataError();
+          return;
+        }
+        if (mBIH.compression == BI_RLE4 && mBIH.bpp != 4 && mBIH.bpp != 1) {
+          PR_LOG(GetBMPLog(), PR_LOG_DEBUG, 
+                 ("BMP RLE4 compression only supports 4 bits per pixel\n"));
+          PostDataError();
+          return;
+        }
+        if (mBIH.compression == BI_ALPHABITFIELDS && 
+            mBIH.bpp != 16 && mBIH.bpp != 32) {
+          PR_LOG(GetBMPLog(), PR_LOG_DEBUG, 
+                 ("BMP ALPHABITFIELDS only supports 16 or 32 bits per pixel\n"));
+          PostDataError();
+          return;
+        }
+
+        if (mBIH.compression != BI_RLE8 && mBIH.compression != BI_RLE4 &&
+            mBIH.compression != BI_ALPHABITFIELDS) {
+            // mRow is not used for RLE encoded images
+            mRow = (uint8_t*)moz_malloc((mBIH.width * mBIH.bpp) / 8 + 4);
+            // + 4 because the line is padded to a 4 bit boundary, but I don't want
+            // to make exact calculations here, that's unnecessary.
+            // Also, it compensates rounding error.
+            if (!mRow) {
+              PostDataError();
+              return;
+            }
+        }
+        if (!mImageData) {
+            PostDecoderError(NS_ERROR_FAILURE);
+            return;
+        }
+
+        // Prepare for transparency
+        if ((mBIH.compression == BI_RLE8) || (mBIH.compression == BI_RLE4)) {
+            // Clear the image, as the RLE may jump over areas
+            memset(mImageData, 0, mImageDataLength);
+        }
+    }
+
+    if (mColors && mPos >= mLOH) {
+      // OS/2 Bitmaps have no padding byte
+      uint8_t bytesPerColor = (mBFH.bihsize == OS2_BIH_LENGTH) ? 3 : 4;
+      if (mPos < (mLOH + mNumColors * bytesPerColor)) {
+        // Number of bytes already received
+        uint32_t colorBytes = mPos - mLOH; 
+        // Color which is currently received
+        uint8_t colorNum = colorBytes / bytesPerColor;
+        uint8_t at = colorBytes % bytesPerColor;
+        while (aCount && (mPos < (mLOH + mNumColors * bytesPerColor))) {
+            switch (at) {
+                case 0:
+                    mColors[colorNum].blue = *aBuffer;
+                    break;
+                case 1:
+                    mColors[colorNum].green = *aBuffer;
+                    break;
+                case 2:
+                    mColors[colorNum].red = *aBuffer;
+                    // If there is no padding byte, increment the color index
+                    // since we're done with the current color.
+                    if (bytesPerColor == 3)
+                      colorNum++;
+                    break;
+                case 3:
+                    // This is a padding byte only in Windows BMPs. Increment
+                    // the color index since we're done with the current color.
+                    colorNum++;
+                    break;
+            }
+            mPos++; aBuffer++; aCount--;
+            at = (at + 1) % bytesPerColor;
+        }
+      }
+    }
+    else if (aCount && mBIH.compression == BI_BITFIELDS && mPos < (WIN_V3_HEADER_LENGTH + BITFIELD_LENGTH)) {
+        // If compression is used, this is a windows bitmap, hence we can
+        // use WIN_HEADER_LENGTH instead of mLOH
+        uint32_t toCopy = (WIN_V3_HEADER_LENGTH + BITFIELD_LENGTH) - mPos;
+        if (toCopy > aCount)
+            toCopy = aCount;
+        memcpy(mRawBuf + (mPos - WIN_V3_HEADER_LENGTH), aBuffer, toCopy);
+        mPos += toCopy;
+        aBuffer += toCopy;
+        aCount -= toCopy;
+    }
+    if (mPos == WIN_V3_HEADER_LENGTH + BITFIELD_LENGTH && 
+        mBIH.compression == BI_BITFIELDS) {
+        mBitFields.red = LittleEndian::readUint32(reinterpret_cast<uint32_t*>(mRawBuf));
+        mBitFields.green = LittleEndian::readUint32(reinterpret_cast<uint32_t*>(mRawBuf + 4));
+        mBitFields.blue = LittleEndian::readUint32(reinterpret_cast<uint32_t*>(mRawBuf + 8));
+        CalcBitShift();
+    }
+    while (aCount && (mPos < mBFH.dataoffset)) { // Skip whatever is between header and data
+        mPos++; aBuffer++; aCount--;
+    }
+    if (aCount && ++mPos >= mBFH.dataoffset) {
+        // Need to increment mPos, else we might get to mPos==mLOH again
+        // From now on, mPos is irrelevant
+        if (!mBIH.compression || mBIH.compression == BI_BITFIELDS) {
+            uint32_t rowSize = (mBIH.bpp * mBIH.width + 7) / 8; // + 7 to round up
+            if (rowSize % 4) {
+                rowSize += (4 - (rowSize % 4)); // Pad to DWORD Boundary
+            }
+            uint32_t toCopy;
+            do {
+                toCopy = rowSize - mRowBytes;
+                if (toCopy) {
+                    if (toCopy > aCount)
+                        toCopy = aCount;
+                    memcpy(mRow + mRowBytes, aBuffer, toCopy);
+                    aCount -= toCopy;
+                    aBuffer += toCopy;
+                    mRowBytes += toCopy;
+                }
+                if (rowSize == mRowBytes) {
+                    // Collected a whole row into mRow, process it
+                    uint8_t* p = mRow;
+                    uint32_t* d = reinterpret_cast<uint32_t*>(mImageData) + PIXEL_OFFSET(mCurLine, 0);
+                    uint32_t lpos = mBIH.width;
+                    switch (mBIH.bpp) {
+                      case 1:
+                        while (lpos > 0) {
+                          int8_t bit;
+                          uint8_t idx;
+                          for (bit = 7; bit >= 0 && lpos > 0; bit--) {
+                              idx = (*p >> bit) & 1;
+                              SetPixel(d, idx, mColors);
+                              --lpos;
+                          }
+                          ++p;
+                        }
+                        break;
+                      case 4:
+                        while (lpos > 0) {
+                          Set4BitPixel(d, *p, lpos, mColors);
+                          ++p;
+                        }
+                        break;
+                      case 8:
+                        while (lpos > 0) {
+                          SetPixel(d, *p, mColors);
+                          --lpos;
+                          ++p;
+                        }
+                        break;
+                      case 16:
+                        while (lpos > 0) {
+                          uint16_t val = LittleEndian::readUint16(reinterpret_cast<uint16_t*>(p));
+                          SetPixel(d,
+                                  (val & mBitFields.red) >> mBitFields.redRightShift << mBitFields.redLeftShift,
+                                  (val & mBitFields.green) >> mBitFields.greenRightShift << mBitFields.greenLeftShift,
+                                  (val & mBitFields.blue) >> mBitFields.blueRightShift << mBitFields.blueLeftShift);
+                          --lpos;
+                          p+=2;
+                        }
+                        break;
+                      case 24:
+                        while (lpos > 0) {
+                          SetPixel(d, p[2], p[1], p[0]);
+                          p += 2;
+                          --lpos;
+                          ++p;
+                        }
+                        break;
+                      case 32:
+                        while (lpos > 0) {
+                          if (mUseAlphaData) {
+                            if (!mHaveAlphaData && p[3]) {
+                              // Non-zero alpha byte detected! Clear previous
+                              // pixels that we have already processed.
+                              // This works because we know that if we 
+                              // are reaching here then the alpha data in byte 
+                              // 4 has been right all along.  And we know it
+                              // has been set to 0 the whole time, so that 
+                              // means that everything is transparent so far.
+                              uint32_t* start = reinterpret_cast<uint32_t*>(mImageData) + GetWidth() * (mCurLine - 1);
+                              uint32_t heightDifference = GetHeight() - mCurLine + 1;
+                              uint32_t pixelCount = GetWidth() * heightDifference;
+
+                              memset(start, 0, pixelCount * sizeof(uint32_t));
+
+                              mHaveAlphaData = true;
+                            }
+                            SetPixel(d, p[2], p[1], p[0], mHaveAlphaData ? p[3] : 0xFF);
+                          } else {
+                            SetPixel(d, p[2], p[1], p[0]);
+                          }
+                          p += 4;
+                          --lpos;
+                        }
+                        break;
+                      default:
+                        NS_NOTREACHED("Unsupported color depth, but earlier check didn't catch it");
+                    }
+                    mCurLine --;
+                    if (mCurLine == 0) { // Finished last line
+                      break;
+                    }
+                    mRowBytes = 0;
+
+                }
+            } while (aCount > 0);
+        }
+        else if ((mBIH.compression == BI_RLE8) || (mBIH.compression == BI_RLE4)) {
+            if (((mBIH.compression == BI_RLE8) && (mBIH.bpp != 8)) || 
+                ((mBIH.compression == BI_RLE4) && (mBIH.bpp != 4) && (mBIH.bpp != 1))) {
+              PR_LOG(GetBMPLog(), PR_LOG_DEBUG, ("BMP RLE8/RLE4 compression only supports 8/4 bits per pixel\n"));
+              PostDataError();
+              return;
+            }
+
+            while (aCount > 0) {
+                uint8_t byte;
+
+                switch(mState) {
+                    case eRLEStateInitial:
+                        mStateData = (uint8_t)*aBuffer++;
+                        aCount--;
+
+                        mState = eRLEStateNeedSecondEscapeByte;
+                        continue;
+
+                    case eRLEStateNeedSecondEscapeByte:
+                        byte = *aBuffer++;
+                        aCount--;
+                        if (mStateData != RLE_ESCAPE) { // encoded mode
+                            // Encoded mode consists of two bytes: 
+                            // the first byte (mStateData) specifies the
+                            // number of consecutive pixels to be drawn 
+                            // using the color index contained in
+                            // the second byte
+                            // Work around bitmaps that specify too many pixels
+                            mState = eRLEStateInitial;
+                            uint32_t pixelsNeeded = std::min<uint32_t>(mBIH.width - mCurPos, mStateData);
+                            if (pixelsNeeded) {
+                                uint32_t* d = reinterpret_cast<uint32_t*>(mImageData) + PIXEL_OFFSET(mCurLine, mCurPos);
+                                mCurPos += pixelsNeeded;
+                                if (mBIH.compression == BI_RLE8) {
+                                    do {
+                                        SetPixel(d, byte, mColors);
+                                        pixelsNeeded --;
+                                    } while (pixelsNeeded);
+                                } else {
+                                    do {
+                                        Set4BitPixel(d, byte, pixelsNeeded, mColors);
+                                    } while (pixelsNeeded);
+                                }
+                            }
+                            continue;
+                        }
+
+                        switch(byte) {
+                            case RLE_ESCAPE_EOL:
+                                // End of Line: Go to next row
+                                mCurLine --;
+                                mCurPos = 0;
+                                mState = eRLEStateInitial;
+                                break;
+
+                            case RLE_ESCAPE_EOF: // EndOfFile
+                                mCurPos = mCurLine = 0;
+                                break;
+
+                            case RLE_ESCAPE_DELTA:
+                                mState = eRLEStateNeedXDelta;
+                                continue;
+
+                            default : // absolute mode
+                                // Save the number of pixels to read
+                                mStateData = byte;
+                                if (mCurPos + mStateData > (uint32_t)mBIH.width) {
+                                    // We can work around bitmaps that specify one
+                                    // pixel too many, but only if their width is odd.
+                                    mStateData -= mBIH.width & 1;
+                                    if (mCurPos + mStateData > (uint32_t)mBIH.width) {
+                                        PostDataError();
+                                        return;
+                                    }
+                                }
+
+                                // See if we will need to skip a byte
+                                // to word align the pixel data
+                                // mStateData is a number of pixels
+                                // so allow for the RLE compression type
+                                // Pixels RLE8=1 RLE4=2
+                                //    1    Pad    Pad
+                                //    2    No     Pad
+                                //    3    Pad    No
+                                //    4    No     No
+                                if (((mStateData - 1) & mBIH.compression) != 0)
+                                    mState = eRLEStateAbsoluteMode;
+                                else
+                                    mState = eRLEStateAbsoluteModePadded;
+                                continue;
+                        }
+                        break;
+
+                    case eRLEStateNeedXDelta:
+                        // Handle the XDelta and proceed to get Y Delta
+                        byte = *aBuffer++;
+                        aCount--;
+                        mCurPos += byte;
+                        if (mCurPos > mBIH.width)
+                            mCurPos = mBIH.width;
+
+                        mState = eRLEStateNeedYDelta;
+                        continue;
+
+                    case eRLEStateNeedYDelta:
+                        // Get the Y Delta and then "handle" the move
+                        byte = *aBuffer++;
+                        aCount--;
+                        mState = eRLEStateInitial;
+                        mCurLine -= std::min<int32_t>(byte, mCurLine);
+                        break;
+
+                    case eRLEStateAbsoluteMode: // Absolute Mode
+                    case eRLEStateAbsoluteModePadded:
+                        if (mStateData) {
+                            // In absolute mode, the second byte (mStateData)
+                            // represents the number of pixels 
+                            // that follow, each of which contains 
+                            // the color index of a single pixel.
+                            uint32_t* d = reinterpret_cast<uint32_t*>(mImageData) + PIXEL_OFFSET(mCurLine, mCurPos);
+                            uint32_t* oldPos = d;
+                            if (mBIH.compression == BI_RLE8) {
+                                while (aCount > 0 && mStateData > 0) {
+                                    byte = *aBuffer++;
+                                    aCount--;
+                                    SetPixel(d, byte, mColors);
+                                    mStateData--;
+                                }
+                            } else {
+                                while (aCount > 0 && mStateData > 0) {
+                                    byte = *aBuffer++;
+                                    aCount--;
+                                    Set4BitPixel(d, byte, mStateData, mColors);
+                                }
+                            }
+                            mCurPos += d - oldPos;
+                        }
+
+                        if (mStateData == 0) {
+                            // In absolute mode, each run must 
+                            // be aligned on a word boundary
+
+                            if (mState == eRLEStateAbsoluteMode) { // Word Aligned
+                                mState = eRLEStateInitial;
+                            } else if (aCount > 0) {               // Not word Aligned
+                                // "next" byte is just a padding byte
+                                // so "move" past it and we can continue
+                                aBuffer++;
+                                aCount--;
+                                mState = eRLEStateInitial;
+                            }
+                        }
+                        // else state is still eRLEStateAbsoluteMode
+                        continue;
+
+                    default :
+                        NS_ABORT_IF_FALSE(0, "BMP RLE decompression: unknown state!");
+                        PostDecoderError(NS_ERROR_UNEXPECTED);
+                        return;
+                }
+                // Because of the use of the continue statement
+                // we only get here for eol, eof or y delta
+                if (mCurLine == 0) { // Finished last line
+                    break;
+                }
+            }
+        }
+    }
+
+    const uint32_t rows = mOldLine - mCurLine;
+    if (rows) {
+
+        // Invalidate
+        nsIntRect r(0, mBIH.height < 0 ? -mBIH.height - mOldLine : mCurLine,
+                    mBIH.width, rows);
+        PostInvalidation(r);
+
+        mOldLine = mCurLine;
+    }
+
+    return;
+}
+
+void nsBMPDecoder::ProcessFileHeader()
+{
+    memset(&mBFH, 0, sizeof(mBFH));
+    memcpy(&mBFH.signature, mRawBuf, sizeof(mBFH.signature));
+    memcpy(&mBFH.filesize, mRawBuf + 2, sizeof(mBFH.filesize));
+    memcpy(&mBFH.reserved, mRawBuf + 6, sizeof(mBFH.reserved));
+    memcpy(&mBFH.dataoffset, mRawBuf + 10, sizeof(mBFH.dataoffset));
+    memcpy(&mBFH.bihsize, mRawBuf + 14, sizeof(mBFH.bihsize));
+
+    // Now correct the endianness of the header
+    mBFH.filesize = LittleEndian::readUint32(&mBFH.filesize);
+    mBFH.dataoffset = LittleEndian::readUint32(&mBFH.dataoffset);
+    mBFH.bihsize = LittleEndian::readUint32(&mBFH.bihsize);
+}
+
+void nsBMPDecoder::ProcessInfoHeader()
+{
+    memset(&mBIH, 0, sizeof(mBIH));
+    if (mBFH.bihsize == 12) { // OS/2 Bitmap
+        memcpy(&mBIH.width, mRawBuf, 2);
+        memcpy(&mBIH.height, mRawBuf + 2, 2);
+        memcpy(&mBIH.planes, mRawBuf + 4, sizeof(mBIH.planes));
+        memcpy(&mBIH.bpp, mRawBuf + 6, sizeof(mBIH.bpp));
+    }
+    else {
+        memcpy(&mBIH.width, mRawBuf, sizeof(mBIH.width));
+        memcpy(&mBIH.height, mRawBuf + 4, sizeof(mBIH.height));
+        memcpy(&mBIH.planes, mRawBuf + 8, sizeof(mBIH.planes));
+        memcpy(&mBIH.bpp, mRawBuf + 10, sizeof(mBIH.bpp));
+        memcpy(&mBIH.compression, mRawBuf + 12, sizeof(mBIH.compression));
+        memcpy(&mBIH.image_size, mRawBuf + 16, sizeof(mBIH.image_size));
+        memcpy(&mBIH.xppm, mRawBuf + 20, sizeof(mBIH.xppm));
+        memcpy(&mBIH.yppm, mRawBuf + 24, sizeof(mBIH.yppm));
+        memcpy(&mBIH.colors, mRawBuf + 28, sizeof(mBIH.colors));
+        memcpy(&mBIH.important_colors, mRawBuf + 32, sizeof(mBIH.important_colors));
+    }
+
+    // Convert endianness
+    mBIH.width = LittleEndian::readUint32(&mBIH.width);
+    mBIH.height = LittleEndian::readUint32(&mBIH.height);
+    mBIH.planes = LittleEndian::readUint16(&mBIH.planes);
+    mBIH.bpp = LittleEndian::readUint16(&mBIH.bpp);
+
+    mBIH.compression = LittleEndian::readUint32(&mBIH.compression);
+    mBIH.image_size = LittleEndian::readUint32(&mBIH.image_size);
+    mBIH.xppm = LittleEndian::readUint32(&mBIH.xppm);
+    mBIH.yppm = LittleEndian::readUint32(&mBIH.yppm);
+    mBIH.colors = LittleEndian::readUint32(&mBIH.colors);
+    mBIH.important_colors = LittleEndian::readUint32(&mBIH.important_colors);
+}
+
+} // namespace image
+} // namespace mozilla