michael@0: /* vim:set tw=80 expandtab softtabstop=4 ts=4 sw=4: */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: /* I got the format description from http://www.daubnet.com/formats/BMP.html */
michael@0: 
michael@0: /* This is a Cross-Platform BMP Decoder, which should work everywhere, including
michael@0:  * Big-Endian machines like the PowerPC. */
michael@0: 
michael@0: #include <stdlib.h>
michael@0: 
michael@0: #include "ImageLogging.h"
michael@0: #include "mozilla/Endian.h"
michael@0: #include "nsBMPDecoder.h"
michael@0: 
michael@0: #include "nsIInputStream.h"
michael@0: #include "RasterImage.h"
michael@0: #include <algorithm>
michael@0: 
michael@0: namespace mozilla {
michael@0: namespace image {
michael@0: 
michael@0: #ifdef PR_LOGGING
michael@0: static PRLogModuleInfo *
michael@0: GetBMPLog()
michael@0: {
michael@0:   static PRLogModuleInfo *sBMPLog;
michael@0:   if (!sBMPLog)
michael@0:     sBMPLog = PR_NewLogModule("BMPDecoder");
michael@0:   return sBMPLog;
michael@0: }
michael@0: #endif
michael@0: 
michael@0: // Convert from row (1..height) to absolute line (0..height-1)
michael@0: #define LINE(row) ((mBIH.height < 0) ? (-mBIH.height - (row)) : ((row) - 1))
michael@0: #define PIXEL_OFFSET(row, col) (LINE(row) * mBIH.width + col)
michael@0: 
michael@0: nsBMPDecoder::nsBMPDecoder(RasterImage &aImage)
michael@0:  : Decoder(aImage)
michael@0: {
michael@0:   mColors = nullptr;
michael@0:   mRow = nullptr;
michael@0:   mCurPos = mPos = mNumColors = mRowBytes = 0;
michael@0:   mOldLine = mCurLine = 1; // Otherwise decoder will never start
michael@0:   mState = eRLEStateInitial;
michael@0:   mStateData = 0;
michael@0:   mLOH = WIN_V3_HEADER_LENGTH;
michael@0:   mUseAlphaData = mHaveAlphaData = false;
michael@0: }
michael@0: 
michael@0: nsBMPDecoder::~nsBMPDecoder()
michael@0: {
michael@0:   delete[] mColors;
michael@0:   if (mRow) {
michael@0:       moz_free(mRow);
michael@0:   }
michael@0: }
michael@0: 
michael@0: // Sets whether or not the BMP will use alpha data
michael@0: void 
michael@0: nsBMPDecoder::SetUseAlphaData(bool useAlphaData) 
michael@0: {
michael@0:   mUseAlphaData = useAlphaData;
michael@0: }
michael@0: 
michael@0: // Obtains the bits per pixel from the internal BIH header
michael@0: int32_t 
michael@0: nsBMPDecoder::GetBitsPerPixel() const
michael@0: {
michael@0:   return mBIH.bpp;
michael@0: }
michael@0: 
michael@0: // Obtains the width from the internal BIH header
michael@0: int32_t 
michael@0: nsBMPDecoder::GetWidth() const
michael@0: {
michael@0:   return mBIH.width; 
michael@0: }
michael@0: 
michael@0: // Obtains the abs-value of the height from the internal BIH header
michael@0: int32_t 
michael@0: nsBMPDecoder::GetHeight() const
michael@0: {
michael@0:   return abs(mBIH.height);
michael@0: }
michael@0: 
michael@0: // Obtains the internal output image buffer
michael@0: uint32_t* 
michael@0: nsBMPDecoder::GetImageData() 
michael@0: {
michael@0:   return reinterpret_cast<uint32_t*>(mImageData);
michael@0: }
michael@0: 
michael@0: // Obtains the size of the compressed image resource
michael@0: int32_t 
michael@0: nsBMPDecoder::GetCompressedImageSize() const
michael@0: {
michael@0:   // For everything except BI_RGB the header field must be defined
michael@0:   if (mBIH.compression != BI_RGB) {
michael@0:     return mBIH.image_size;
michael@0:   }
michael@0: 
michael@0:   // mBIH.image_size isn't always filled for BI_RGB so calculate it manually
michael@0:   // The pixel array size is calculated based on extra 4 byte boundary padding
michael@0:   uint32_t rowSize = (mBIH.bpp * mBIH.width + 7) / 8; // + 7 to round up
michael@0:   // Pad to DWORD Boundary
michael@0:   if (rowSize % 4) {
michael@0:     rowSize += (4 - (rowSize % 4));
michael@0:   }
michael@0: 
michael@0:   // The height should be the absolute value of what the height is in the BIH.
michael@0:   // If positive the bitmap is stored bottom to top, otherwise top to bottom
michael@0:   int32_t pixelArraySize = rowSize * GetHeight();
michael@0:   return pixelArraySize;
michael@0: }
michael@0: 
michael@0: // Obtains whether or not a BMP file had alpha data in its 4th byte
michael@0: // for 32BPP bitmaps.  Only use after the bitmap has been processed.
michael@0: bool 
michael@0: nsBMPDecoder::HasAlphaData() const 
michael@0: {
michael@0:   return mHaveAlphaData;
michael@0: }
michael@0: 
michael@0: 
michael@0: void
michael@0: nsBMPDecoder::FinishInternal()
michael@0: {
michael@0:     // We shouldn't be called in error cases
michael@0:     NS_ABORT_IF_FALSE(!HasError(), "Can't call FinishInternal on error!");
michael@0: 
michael@0:     // We should never make multiple frames
michael@0:     NS_ABORT_IF_FALSE(GetFrameCount() <= 1, "Multiple BMP frames?");
michael@0: 
michael@0:     // Send notifications if appropriate
michael@0:     if (!IsSizeDecode() && HasSize()) {
michael@0: 
michael@0:         // Invalidate
michael@0:         nsIntRect r(0, 0, mBIH.width, GetHeight());
michael@0:         PostInvalidation(r);
michael@0: 
michael@0:         if (mUseAlphaData) {
michael@0:           PostFrameStop(FrameBlender::kFrameHasAlpha);
michael@0:         } else {
michael@0:           PostFrameStop(FrameBlender::kFrameOpaque);
michael@0:         }
michael@0:         PostDecodeDone();
michael@0:     }
michael@0: }
michael@0: 
michael@0: // ----------------------------------------
michael@0: // Actual Data Processing
michael@0: // ----------------------------------------
michael@0: 
michael@0: static void calcBitmask(uint32_t aMask, uint8_t& aBegin, uint8_t& aLength)
michael@0: {
michael@0:     // find the rightmost 1
michael@0:     uint8_t pos;
michael@0:     bool started = false;
michael@0:     aBegin = aLength = 0;
michael@0:     for (pos = 0; pos <= 31; pos++) {
michael@0:         if (!started && (aMask & (1 << pos))) {
michael@0:             aBegin = pos;
michael@0:             started = true;
michael@0:         }
michael@0:         else if (started && !(aMask & (1 << pos))) {
michael@0:             aLength = pos - aBegin;
michael@0:             break;
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: NS_METHOD nsBMPDecoder::CalcBitShift()
michael@0: {
michael@0:     uint8_t begin, length;
michael@0:     // red
michael@0:     calcBitmask(mBitFields.red, begin, length);
michael@0:     mBitFields.redRightShift = begin;
michael@0:     mBitFields.redLeftShift = 8 - length;
michael@0:     // green
michael@0:     calcBitmask(mBitFields.green, begin, length);
michael@0:     mBitFields.greenRightShift = begin;
michael@0:     mBitFields.greenLeftShift = 8 - length;
michael@0:     // blue
michael@0:     calcBitmask(mBitFields.blue, begin, length);
michael@0:     mBitFields.blueRightShift = begin;
michael@0:     mBitFields.blueLeftShift = 8 - length;
michael@0:     return NS_OK;
michael@0: }
michael@0: 
michael@0: void
michael@0: nsBMPDecoder::WriteInternal(const char* aBuffer, uint32_t aCount, DecodeStrategy)
michael@0: {
michael@0:     NS_ABORT_IF_FALSE(!HasError(), "Shouldn't call WriteInternal after error!");
michael@0: 
michael@0:     // aCount=0 means EOF, mCurLine=0 means we're past end of image
michael@0:     if (!aCount || !mCurLine)
michael@0:         return;
michael@0: 
michael@0:     if (mPos < BFH_INTERNAL_LENGTH) { /* In BITMAPFILEHEADER */
michael@0:         uint32_t toCopy = BFH_INTERNAL_LENGTH - mPos;
michael@0:         if (toCopy > aCount)
michael@0:             toCopy = aCount;
michael@0:         memcpy(mRawBuf + mPos, aBuffer, toCopy);
michael@0:         mPos += toCopy;
michael@0:         aCount -= toCopy;
michael@0:         aBuffer += toCopy;
michael@0:     }
michael@0:     if (mPos == BFH_INTERNAL_LENGTH) {
michael@0:         ProcessFileHeader();
michael@0:         if (mBFH.signature[0] != 'B' || mBFH.signature[1] != 'M') {
michael@0:             PostDataError();
michael@0:             return;
michael@0:         }
michael@0:         if (mBFH.bihsize == OS2_BIH_LENGTH)
michael@0:             mLOH = OS2_HEADER_LENGTH;
michael@0:     }
michael@0:     if (mPos >= BFH_INTERNAL_LENGTH && mPos < mLOH) { /* In BITMAPINFOHEADER */
michael@0:         uint32_t toCopy = mLOH - mPos;
michael@0:         if (toCopy > aCount)
michael@0:             toCopy = aCount;
michael@0:         memcpy(mRawBuf + (mPos - BFH_INTERNAL_LENGTH), aBuffer, toCopy);
michael@0:         mPos += toCopy;
michael@0:         aCount -= toCopy;
michael@0:         aBuffer += toCopy;
michael@0:     }
michael@0: 
michael@0:     // HasSize is called to ensure that if at this point mPos == mLOH but
michael@0:     // we have no data left to process, the next time WriteInternal is called
michael@0:     // we won't enter this condition again.
michael@0:     if (mPos == mLOH && !HasSize()) {
michael@0:         ProcessInfoHeader();
michael@0:         PR_LOG(GetBMPLog(), PR_LOG_DEBUG, ("BMP is %lix%lix%lu. compression=%lu\n",
michael@0:                mBIH.width, mBIH.height, mBIH.bpp, mBIH.compression));
michael@0:         // Verify we support this bit depth
michael@0:         if (mBIH.bpp != 1 && mBIH.bpp != 4 && mBIH.bpp != 8 &&
michael@0:             mBIH.bpp != 16 && mBIH.bpp != 24 && mBIH.bpp != 32) {
michael@0:           PostDataError();
michael@0:           return;
michael@0:         }
michael@0: 
michael@0:         // BMPs with negative width are invalid
michael@0:         // Reject extremely wide images to keep the math sane
michael@0:         const int32_t k64KWidth = 0x0000FFFF;
michael@0:         if (mBIH.width < 0 || mBIH.width > k64KWidth) {
michael@0:             PostDataError();
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         if (mBIH.height == INT_MIN) {
michael@0:             PostDataError();
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         uint32_t real_height = GetHeight();
michael@0: 
michael@0:         // Post our size to the superclass
michael@0:         PostSize(mBIH.width, real_height);
michael@0:         if (HasError()) {
michael@0:           // Setting the size led to an error.
michael@0:           return;
michael@0:         }
michael@0: 
michael@0:         // We have the size. If we're doing a size decode, we got what
michael@0:         // we came for.
michael@0:         if (IsSizeDecode())
michael@0:             return;
michael@0: 
michael@0:         // We're doing a real decode.
michael@0:         mOldLine = mCurLine = real_height;
michael@0: 
michael@0:         if (mBIH.bpp <= 8) {
michael@0:             mNumColors = 1 << mBIH.bpp;
michael@0:             if (mBIH.colors && mBIH.colors < mNumColors)
michael@0:                 mNumColors = mBIH.colors;
michael@0: 
michael@0:             // Always allocate 256 even though mNumColors might be smaller
michael@0:             mColors = new colorTable[256];
michael@0:             memset(mColors, 0, 256 * sizeof(colorTable));
michael@0:         }
michael@0:         else if (mBIH.compression != BI_BITFIELDS && mBIH.bpp == 16) {
michael@0:             // Use default 5-5-5 format
michael@0:             mBitFields.red   = 0x7C00;
michael@0:             mBitFields.green = 0x03E0;
michael@0:             mBitFields.blue  = 0x001F;
michael@0:             CalcBitShift();
michael@0:         }
michael@0: 
michael@0:         // Make sure we have a valid value for our supported compression modes
michael@0:         // before adding the frame
michael@0:         if (mBIH.compression != BI_RGB && mBIH.compression != BI_RLE8 && 
michael@0:             mBIH.compression != BI_RLE4 && mBIH.compression != BI_BITFIELDS) {
michael@0:           PostDataError();
michael@0:           return;
michael@0:         }
michael@0: 
michael@0:         // If we have RLE4 or RLE8 or BI_ALPHABITFIELDS, then ensure we
michael@0:         // have valid BPP values before adding the frame
michael@0:         if (mBIH.compression == BI_RLE8 && mBIH.bpp != 8) {
michael@0:           PR_LOG(GetBMPLog(), PR_LOG_DEBUG, 
michael@0:                  ("BMP RLE8 compression only supports 8 bits per pixel\n"));
michael@0:           PostDataError();
michael@0:           return;
michael@0:         }
michael@0:         if (mBIH.compression == BI_RLE4 && mBIH.bpp != 4 && mBIH.bpp != 1) {
michael@0:           PR_LOG(GetBMPLog(), PR_LOG_DEBUG, 
michael@0:                  ("BMP RLE4 compression only supports 4 bits per pixel\n"));
michael@0:           PostDataError();
michael@0:           return;
michael@0:         }
michael@0:         if (mBIH.compression == BI_ALPHABITFIELDS && 
michael@0:             mBIH.bpp != 16 && mBIH.bpp != 32) {
michael@0:           PR_LOG(GetBMPLog(), PR_LOG_DEBUG, 
michael@0:                  ("BMP ALPHABITFIELDS only supports 16 or 32 bits per pixel\n"));
michael@0:           PostDataError();
michael@0:           return;
michael@0:         }
michael@0: 
michael@0:         if (mBIH.compression != BI_RLE8 && mBIH.compression != BI_RLE4 &&
michael@0:             mBIH.compression != BI_ALPHABITFIELDS) {
michael@0:             // mRow is not used for RLE encoded images
michael@0:             mRow = (uint8_t*)moz_malloc((mBIH.width * mBIH.bpp) / 8 + 4);
michael@0:             // + 4 because the line is padded to a 4 bit boundary, but I don't want
michael@0:             // to make exact calculations here, that's unnecessary.
michael@0:             // Also, it compensates rounding error.
michael@0:             if (!mRow) {
michael@0:               PostDataError();
michael@0:               return;
michael@0:             }
michael@0:         }
michael@0:         if (!mImageData) {
michael@0:             PostDecoderError(NS_ERROR_FAILURE);
michael@0:             return;
michael@0:         }
michael@0: 
michael@0:         // Prepare for transparency
michael@0:         if ((mBIH.compression == BI_RLE8) || (mBIH.compression == BI_RLE4)) {
michael@0:             // Clear the image, as the RLE may jump over areas
michael@0:             memset(mImageData, 0, mImageDataLength);
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     if (mColors && mPos >= mLOH) {
michael@0:       // OS/2 Bitmaps have no padding byte
michael@0:       uint8_t bytesPerColor = (mBFH.bihsize == OS2_BIH_LENGTH) ? 3 : 4;
michael@0:       if (mPos < (mLOH + mNumColors * bytesPerColor)) {
michael@0:         // Number of bytes already received
michael@0:         uint32_t colorBytes = mPos - mLOH; 
michael@0:         // Color which is currently received
michael@0:         uint8_t colorNum = colorBytes / bytesPerColor;
michael@0:         uint8_t at = colorBytes % bytesPerColor;
michael@0:         while (aCount && (mPos < (mLOH + mNumColors * bytesPerColor))) {
michael@0:             switch (at) {
michael@0:                 case 0:
michael@0:                     mColors[colorNum].blue = *aBuffer;
michael@0:                     break;
michael@0:                 case 1:
michael@0:                     mColors[colorNum].green = *aBuffer;
michael@0:                     break;
michael@0:                 case 2:
michael@0:                     mColors[colorNum].red = *aBuffer;
michael@0:                     // If there is no padding byte, increment the color index
michael@0:                     // since we're done with the current color.
michael@0:                     if (bytesPerColor == 3)
michael@0:                       colorNum++;
michael@0:                     break;
michael@0:                 case 3:
michael@0:                     // This is a padding byte only in Windows BMPs. Increment
michael@0:                     // the color index since we're done with the current color.
michael@0:                     colorNum++;
michael@0:                     break;
michael@0:             }
michael@0:             mPos++; aBuffer++; aCount--;
michael@0:             at = (at + 1) % bytesPerColor;
michael@0:         }
michael@0:       }
michael@0:     }
michael@0:     else if (aCount && mBIH.compression == BI_BITFIELDS && mPos < (WIN_V3_HEADER_LENGTH + BITFIELD_LENGTH)) {
michael@0:         // If compression is used, this is a windows bitmap, hence we can
michael@0:         // use WIN_HEADER_LENGTH instead of mLOH
michael@0:         uint32_t toCopy = (WIN_V3_HEADER_LENGTH + BITFIELD_LENGTH) - mPos;
michael@0:         if (toCopy > aCount)
michael@0:             toCopy = aCount;
michael@0:         memcpy(mRawBuf + (mPos - WIN_V3_HEADER_LENGTH), aBuffer, toCopy);
michael@0:         mPos += toCopy;
michael@0:         aBuffer += toCopy;
michael@0:         aCount -= toCopy;
michael@0:     }
michael@0:     if (mPos == WIN_V3_HEADER_LENGTH + BITFIELD_LENGTH && 
michael@0:         mBIH.compression == BI_BITFIELDS) {
michael@0:         mBitFields.red = LittleEndian::readUint32(reinterpret_cast<uint32_t*>(mRawBuf));
michael@0:         mBitFields.green = LittleEndian::readUint32(reinterpret_cast<uint32_t*>(mRawBuf + 4));
michael@0:         mBitFields.blue = LittleEndian::readUint32(reinterpret_cast<uint32_t*>(mRawBuf + 8));
michael@0:         CalcBitShift();
michael@0:     }
michael@0:     while (aCount && (mPos < mBFH.dataoffset)) { // Skip whatever is between header and data
michael@0:         mPos++; aBuffer++; aCount--;
michael@0:     }
michael@0:     if (aCount && ++mPos >= mBFH.dataoffset) {
michael@0:         // Need to increment mPos, else we might get to mPos==mLOH again
michael@0:         // From now on, mPos is irrelevant
michael@0:         if (!mBIH.compression || mBIH.compression == BI_BITFIELDS) {
michael@0:             uint32_t rowSize = (mBIH.bpp * mBIH.width + 7) / 8; // + 7 to round up
michael@0:             if (rowSize % 4) {
michael@0:                 rowSize += (4 - (rowSize % 4)); // Pad to DWORD Boundary
michael@0:             }
michael@0:             uint32_t toCopy;
michael@0:             do {
michael@0:                 toCopy = rowSize - mRowBytes;
michael@0:                 if (toCopy) {
michael@0:                     if (toCopy > aCount)
michael@0:                         toCopy = aCount;
michael@0:                     memcpy(mRow + mRowBytes, aBuffer, toCopy);
michael@0:                     aCount -= toCopy;
michael@0:                     aBuffer += toCopy;
michael@0:                     mRowBytes += toCopy;
michael@0:                 }
michael@0:                 if (rowSize == mRowBytes) {
michael@0:                     // Collected a whole row into mRow, process it
michael@0:                     uint8_t* p = mRow;
michael@0:                     uint32_t* d = reinterpret_cast<uint32_t*>(mImageData) + PIXEL_OFFSET(mCurLine, 0);
michael@0:                     uint32_t lpos = mBIH.width;
michael@0:                     switch (mBIH.bpp) {
michael@0:                       case 1:
michael@0:                         while (lpos > 0) {
michael@0:                           int8_t bit;
michael@0:                           uint8_t idx;
michael@0:                           for (bit = 7; bit >= 0 && lpos > 0; bit--) {
michael@0:                               idx = (*p >> bit) & 1;
michael@0:                               SetPixel(d, idx, mColors);
michael@0:                               --lpos;
michael@0:                           }
michael@0:                           ++p;
michael@0:                         }
michael@0:                         break;
michael@0:                       case 4:
michael@0:                         while (lpos > 0) {
michael@0:                           Set4BitPixel(d, *p, lpos, mColors);
michael@0:                           ++p;
michael@0:                         }
michael@0:                         break;
michael@0:                       case 8:
michael@0:                         while (lpos > 0) {
michael@0:                           SetPixel(d, *p, mColors);
michael@0:                           --lpos;
michael@0:                           ++p;
michael@0:                         }
michael@0:                         break;
michael@0:                       case 16:
michael@0:                         while (lpos > 0) {
michael@0:                           uint16_t val = LittleEndian::readUint16(reinterpret_cast<uint16_t*>(p));
michael@0:                           SetPixel(d,
michael@0:                                   (val & mBitFields.red) >> mBitFields.redRightShift << mBitFields.redLeftShift,
michael@0:                                   (val & mBitFields.green) >> mBitFields.greenRightShift << mBitFields.greenLeftShift,
michael@0:                                   (val & mBitFields.blue) >> mBitFields.blueRightShift << mBitFields.blueLeftShift);
michael@0:                           --lpos;
michael@0:                           p+=2;
michael@0:                         }
michael@0:                         break;
michael@0:                       case 24:
michael@0:                         while (lpos > 0) {
michael@0:                           SetPixel(d, p[2], p[1], p[0]);
michael@0:                           p += 2;
michael@0:                           --lpos;
michael@0:                           ++p;
michael@0:                         }
michael@0:                         break;
michael@0:                       case 32:
michael@0:                         while (lpos > 0) {
michael@0:                           if (mUseAlphaData) {
michael@0:                             if (!mHaveAlphaData && p[3]) {
michael@0:                               // Non-zero alpha byte detected! Clear previous
michael@0:                               // pixels that we have already processed.
michael@0:                               // This works because we know that if we 
michael@0:                               // are reaching here then the alpha data in byte 
michael@0:                               // 4 has been right all along.  And we know it
michael@0:                               // has been set to 0 the whole time, so that 
michael@0:                               // means that everything is transparent so far.
michael@0:                               uint32_t* start = reinterpret_cast<uint32_t*>(mImageData) + GetWidth() * (mCurLine - 1);
michael@0:                               uint32_t heightDifference = GetHeight() - mCurLine + 1;
michael@0:                               uint32_t pixelCount = GetWidth() * heightDifference;
michael@0: 
michael@0:                               memset(start, 0, pixelCount * sizeof(uint32_t));
michael@0: 
michael@0:                               mHaveAlphaData = true;
michael@0:                             }
michael@0:                             SetPixel(d, p[2], p[1], p[0], mHaveAlphaData ? p[3] : 0xFF);
michael@0:                           } else {
michael@0:                             SetPixel(d, p[2], p[1], p[0]);
michael@0:                           }
michael@0:                           p += 4;
michael@0:                           --lpos;
michael@0:                         }
michael@0:                         break;
michael@0:                       default:
michael@0:                         NS_NOTREACHED("Unsupported color depth, but earlier check didn't catch it");
michael@0:                     }
michael@0:                     mCurLine --;
michael@0:                     if (mCurLine == 0) { // Finished last line
michael@0:                       break;
michael@0:                     }
michael@0:                     mRowBytes = 0;
michael@0: 
michael@0:                 }
michael@0:             } while (aCount > 0);
michael@0:         }
michael@0:         else if ((mBIH.compression == BI_RLE8) || (mBIH.compression == BI_RLE4)) {
michael@0:             if (((mBIH.compression == BI_RLE8) && (mBIH.bpp != 8)) || 
michael@0:                 ((mBIH.compression == BI_RLE4) && (mBIH.bpp != 4) && (mBIH.bpp != 1))) {
michael@0:               PR_LOG(GetBMPLog(), PR_LOG_DEBUG, ("BMP RLE8/RLE4 compression only supports 8/4 bits per pixel\n"));
michael@0:               PostDataError();
michael@0:               return;
michael@0:             }
michael@0: 
michael@0:             while (aCount > 0) {
michael@0:                 uint8_t byte;
michael@0: 
michael@0:                 switch(mState) {
michael@0:                     case eRLEStateInitial:
michael@0:                         mStateData = (uint8_t)*aBuffer++;
michael@0:                         aCount--;
michael@0: 
michael@0:                         mState = eRLEStateNeedSecondEscapeByte;
michael@0:                         continue;
michael@0: 
michael@0:                     case eRLEStateNeedSecondEscapeByte:
michael@0:                         byte = *aBuffer++;
michael@0:                         aCount--;
michael@0:                         if (mStateData != RLE_ESCAPE) { // encoded mode
michael@0:                             // Encoded mode consists of two bytes: 
michael@0:                             // the first byte (mStateData) specifies the
michael@0:                             // number of consecutive pixels to be drawn 
michael@0:                             // using the color index contained in
michael@0:                             // the second byte
michael@0:                             // Work around bitmaps that specify too many pixels
michael@0:                             mState = eRLEStateInitial;
michael@0:                             uint32_t pixelsNeeded = std::min<uint32_t>(mBIH.width - mCurPos, mStateData);
michael@0:                             if (pixelsNeeded) {
michael@0:                                 uint32_t* d = reinterpret_cast<uint32_t*>(mImageData) + PIXEL_OFFSET(mCurLine, mCurPos);
michael@0:                                 mCurPos += pixelsNeeded;
michael@0:                                 if (mBIH.compression == BI_RLE8) {
michael@0:                                     do {
michael@0:                                         SetPixel(d, byte, mColors);
michael@0:                                         pixelsNeeded --;
michael@0:                                     } while (pixelsNeeded);
michael@0:                                 } else {
michael@0:                                     do {
michael@0:                                         Set4BitPixel(d, byte, pixelsNeeded, mColors);
michael@0:                                     } while (pixelsNeeded);
michael@0:                                 }
michael@0:                             }
michael@0:                             continue;
michael@0:                         }
michael@0: 
michael@0:                         switch(byte) {
michael@0:                             case RLE_ESCAPE_EOL:
michael@0:                                 // End of Line: Go to next row
michael@0:                                 mCurLine --;
michael@0:                                 mCurPos = 0;
michael@0:                                 mState = eRLEStateInitial;
michael@0:                                 break;
michael@0: 
michael@0:                             case RLE_ESCAPE_EOF: // EndOfFile
michael@0:                                 mCurPos = mCurLine = 0;
michael@0:                                 break;
michael@0: 
michael@0:                             case RLE_ESCAPE_DELTA:
michael@0:                                 mState = eRLEStateNeedXDelta;
michael@0:                                 continue;
michael@0: 
michael@0:                             default : // absolute mode
michael@0:                                 // Save the number of pixels to read
michael@0:                                 mStateData = byte;
michael@0:                                 if (mCurPos + mStateData > (uint32_t)mBIH.width) {
michael@0:                                     // We can work around bitmaps that specify one
michael@0:                                     // pixel too many, but only if their width is odd.
michael@0:                                     mStateData -= mBIH.width & 1;
michael@0:                                     if (mCurPos + mStateData > (uint32_t)mBIH.width) {
michael@0:                                         PostDataError();
michael@0:                                         return;
michael@0:                                     }
michael@0:                                 }
michael@0: 
michael@0:                                 // See if we will need to skip a byte
michael@0:                                 // to word align the pixel data
michael@0:                                 // mStateData is a number of pixels
michael@0:                                 // so allow for the RLE compression type
michael@0:                                 // Pixels RLE8=1 RLE4=2
michael@0:                                 //    1    Pad    Pad
michael@0:                                 //    2    No     Pad
michael@0:                                 //    3    Pad    No
michael@0:                                 //    4    No     No
michael@0:                                 if (((mStateData - 1) & mBIH.compression) != 0)
michael@0:                                     mState = eRLEStateAbsoluteMode;
michael@0:                                 else
michael@0:                                     mState = eRLEStateAbsoluteModePadded;
michael@0:                                 continue;
michael@0:                         }
michael@0:                         break;
michael@0: 
michael@0:                     case eRLEStateNeedXDelta:
michael@0:                         // Handle the XDelta and proceed to get Y Delta
michael@0:                         byte = *aBuffer++;
michael@0:                         aCount--;
michael@0:                         mCurPos += byte;
michael@0:                         if (mCurPos > mBIH.width)
michael@0:                             mCurPos = mBIH.width;
michael@0: 
michael@0:                         mState = eRLEStateNeedYDelta;
michael@0:                         continue;
michael@0: 
michael@0:                     case eRLEStateNeedYDelta:
michael@0:                         // Get the Y Delta and then "handle" the move
michael@0:                         byte = *aBuffer++;
michael@0:                         aCount--;
michael@0:                         mState = eRLEStateInitial;
michael@0:                         mCurLine -= std::min<int32_t>(byte, mCurLine);
michael@0:                         break;
michael@0: 
michael@0:                     case eRLEStateAbsoluteMode: // Absolute Mode
michael@0:                     case eRLEStateAbsoluteModePadded:
michael@0:                         if (mStateData) {
michael@0:                             // In absolute mode, the second byte (mStateData)
michael@0:                             // represents the number of pixels 
michael@0:                             // that follow, each of which contains 
michael@0:                             // the color index of a single pixel.
michael@0:                             uint32_t* d = reinterpret_cast<uint32_t*>(mImageData) + PIXEL_OFFSET(mCurLine, mCurPos);
michael@0:                             uint32_t* oldPos = d;
michael@0:                             if (mBIH.compression == BI_RLE8) {
michael@0:                                 while (aCount > 0 && mStateData > 0) {
michael@0:                                     byte = *aBuffer++;
michael@0:                                     aCount--;
michael@0:                                     SetPixel(d, byte, mColors);
michael@0:                                     mStateData--;
michael@0:                                 }
michael@0:                             } else {
michael@0:                                 while (aCount > 0 && mStateData > 0) {
michael@0:                                     byte = *aBuffer++;
michael@0:                                     aCount--;
michael@0:                                     Set4BitPixel(d, byte, mStateData, mColors);
michael@0:                                 }
michael@0:                             }
michael@0:                             mCurPos += d - oldPos;
michael@0:                         }
michael@0: 
michael@0:                         if (mStateData == 0) {
michael@0:                             // In absolute mode, each run must 
michael@0:                             // be aligned on a word boundary
michael@0: 
michael@0:                             if (mState == eRLEStateAbsoluteMode) { // Word Aligned
michael@0:                                 mState = eRLEStateInitial;
michael@0:                             } else if (aCount > 0) {               // Not word Aligned
michael@0:                                 // "next" byte is just a padding byte
michael@0:                                 // so "move" past it and we can continue
michael@0:                                 aBuffer++;
michael@0:                                 aCount--;
michael@0:                                 mState = eRLEStateInitial;
michael@0:                             }
michael@0:                         }
michael@0:                         // else state is still eRLEStateAbsoluteMode
michael@0:                         continue;
michael@0: 
michael@0:                     default :
michael@0:                         NS_ABORT_IF_FALSE(0, "BMP RLE decompression: unknown state!");
michael@0:                         PostDecoderError(NS_ERROR_UNEXPECTED);
michael@0:                         return;
michael@0:                 }
michael@0:                 // Because of the use of the continue statement
michael@0:                 // we only get here for eol, eof or y delta
michael@0:                 if (mCurLine == 0) { // Finished last line
michael@0:                     break;
michael@0:                 }
michael@0:             }
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     const uint32_t rows = mOldLine - mCurLine;
michael@0:     if (rows) {
michael@0: 
michael@0:         // Invalidate
michael@0:         nsIntRect r(0, mBIH.height < 0 ? -mBIH.height - mOldLine : mCurLine,
michael@0:                     mBIH.width, rows);
michael@0:         PostInvalidation(r);
michael@0: 
michael@0:         mOldLine = mCurLine;
michael@0:     }
michael@0: 
michael@0:     return;
michael@0: }
michael@0: 
michael@0: void nsBMPDecoder::ProcessFileHeader()
michael@0: {
michael@0:     memset(&mBFH, 0, sizeof(mBFH));
michael@0:     memcpy(&mBFH.signature, mRawBuf, sizeof(mBFH.signature));
michael@0:     memcpy(&mBFH.filesize, mRawBuf + 2, sizeof(mBFH.filesize));
michael@0:     memcpy(&mBFH.reserved, mRawBuf + 6, sizeof(mBFH.reserved));
michael@0:     memcpy(&mBFH.dataoffset, mRawBuf + 10, sizeof(mBFH.dataoffset));
michael@0:     memcpy(&mBFH.bihsize, mRawBuf + 14, sizeof(mBFH.bihsize));
michael@0: 
michael@0:     // Now correct the endianness of the header
michael@0:     mBFH.filesize = LittleEndian::readUint32(&mBFH.filesize);
michael@0:     mBFH.dataoffset = LittleEndian::readUint32(&mBFH.dataoffset);
michael@0:     mBFH.bihsize = LittleEndian::readUint32(&mBFH.bihsize);
michael@0: }
michael@0: 
michael@0: void nsBMPDecoder::ProcessInfoHeader()
michael@0: {
michael@0:     memset(&mBIH, 0, sizeof(mBIH));
michael@0:     if (mBFH.bihsize == 12) { // OS/2 Bitmap
michael@0:         memcpy(&mBIH.width, mRawBuf, 2);
michael@0:         memcpy(&mBIH.height, mRawBuf + 2, 2);
michael@0:         memcpy(&mBIH.planes, mRawBuf + 4, sizeof(mBIH.planes));
michael@0:         memcpy(&mBIH.bpp, mRawBuf + 6, sizeof(mBIH.bpp));
michael@0:     }
michael@0:     else {
michael@0:         memcpy(&mBIH.width, mRawBuf, sizeof(mBIH.width));
michael@0:         memcpy(&mBIH.height, mRawBuf + 4, sizeof(mBIH.height));
michael@0:         memcpy(&mBIH.planes, mRawBuf + 8, sizeof(mBIH.planes));
michael@0:         memcpy(&mBIH.bpp, mRawBuf + 10, sizeof(mBIH.bpp));
michael@0:         memcpy(&mBIH.compression, mRawBuf + 12, sizeof(mBIH.compression));
michael@0:         memcpy(&mBIH.image_size, mRawBuf + 16, sizeof(mBIH.image_size));
michael@0:         memcpy(&mBIH.xppm, mRawBuf + 20, sizeof(mBIH.xppm));
michael@0:         memcpy(&mBIH.yppm, mRawBuf + 24, sizeof(mBIH.yppm));
michael@0:         memcpy(&mBIH.colors, mRawBuf + 28, sizeof(mBIH.colors));
michael@0:         memcpy(&mBIH.important_colors, mRawBuf + 32, sizeof(mBIH.important_colors));
michael@0:     }
michael@0: 
michael@0:     // Convert endianness
michael@0:     mBIH.width = LittleEndian::readUint32(&mBIH.width);
michael@0:     mBIH.height = LittleEndian::readUint32(&mBIH.height);
michael@0:     mBIH.planes = LittleEndian::readUint16(&mBIH.planes);
michael@0:     mBIH.bpp = LittleEndian::readUint16(&mBIH.bpp);
michael@0: 
michael@0:     mBIH.compression = LittleEndian::readUint32(&mBIH.compression);
michael@0:     mBIH.image_size = LittleEndian::readUint32(&mBIH.image_size);
michael@0:     mBIH.xppm = LittleEndian::readUint32(&mBIH.xppm);
michael@0:     mBIH.yppm = LittleEndian::readUint32(&mBIH.yppm);
michael@0:     mBIH.colors = LittleEndian::readUint32(&mBIH.colors);
michael@0:     mBIH.important_colors = LittleEndian::readUint32(&mBIH.important_colors);
michael@0: }
michael@0: 
michael@0: } // namespace image
michael@0: } // namespace mozilla