| /* |
| * Copyright 2015 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "SkBmpStandardCodec.h" |
| #include "SkCodecPriv.h" |
| #include "SkColorPriv.h" |
| #include "SkStream.h" |
| |
| /* |
| * Creates an instance of the decoder |
| * Called only by NewFromStream |
| */ |
| SkBmpStandardCodec::SkBmpStandardCodec(int width, int height, const SkEncodedInfo& info, |
| SkStream* stream, uint16_t bitsPerPixel, uint32_t numColors, |
| uint32_t bytesPerColor, uint32_t offset, |
| SkCodec::SkScanlineOrder rowOrder, |
| bool isOpaque, bool inIco) |
| : INHERITED(width, height, info, stream, bitsPerPixel, rowOrder) |
| , fColorTable(nullptr) |
| , fNumColors(numColors) |
| , fBytesPerColor(bytesPerColor) |
| , fOffset(offset) |
| , fSwizzler(nullptr) |
| , fSrcBuffer(new uint8_t [this->srcRowBytes()]) |
| , fIsOpaque(isOpaque) |
| , fInIco(inIco) |
| , fAndMaskRowBytes(fInIco ? SkAlign4(compute_row_bytes(this->getInfo().width(), 1)) : 0) |
| {} |
| |
| /* |
| * Initiates the bitmap decode |
| */ |
| SkCodec::Result SkBmpStandardCodec::onGetPixels(const SkImageInfo& dstInfo, |
| void* dst, size_t dstRowBytes, |
| const Options& opts, |
| SkPMColor* inputColorPtr, |
| int* inputColorCount, |
| int* rowsDecoded) { |
| if (opts.fSubset) { |
| // Subsets are not supported. |
| return kUnimplemented; |
| } |
| if (dstInfo.dimensions() != this->getInfo().dimensions()) { |
| SkCodecPrintf("Error: scaling not supported.\n"); |
| return kInvalidScale; |
| } |
| if (!conversion_possible(dstInfo, this->getInfo())) { |
| SkCodecPrintf("Error: cannot convert input type to output type.\n"); |
| return kInvalidConversion; |
| } |
| |
| Result result = this->prepareToDecode(dstInfo, opts, inputColorPtr, inputColorCount); |
| if (kSuccess != result) { |
| return result; |
| } |
| int rows = this->decodeRows(dstInfo, dst, dstRowBytes, opts); |
| if (rows != dstInfo.height()) { |
| *rowsDecoded = rows; |
| return kIncompleteInput; |
| } |
| return kSuccess; |
| } |
| |
| /* |
| * Process the color table for the bmp input |
| */ |
| bool SkBmpStandardCodec::createColorTable(SkAlphaType dstAlphaType, int* numColors) { |
| // Allocate memory for color table |
| uint32_t colorBytes = 0; |
| SkPMColor colorTable[256]; |
| if (this->bitsPerPixel() <= 8) { |
| // Inform the caller of the number of colors |
| uint32_t maxColors = 1 << this->bitsPerPixel(); |
| if (nullptr != numColors) { |
| // We set the number of colors to maxColors in order to ensure |
| // safe memory accesses. Otherwise, an invalid pixel could |
| // access memory outside of our color table array. |
| *numColors = maxColors; |
| } |
| // Don't bother reading more than maxColors. |
| const uint32_t numColorsToRead = |
| fNumColors == 0 ? maxColors : SkTMin(fNumColors, maxColors); |
| |
| // Read the color table from the stream |
| colorBytes = numColorsToRead * fBytesPerColor; |
| SkAutoTDeleteArray<uint8_t> cBuffer(new uint8_t[colorBytes]); |
| if (stream()->read(cBuffer.get(), colorBytes) != colorBytes) { |
| SkCodecPrintf("Error: unable to read color table.\n"); |
| return false; |
| } |
| |
| // Choose the proper packing function |
| SkPMColor (*packARGB) (uint32_t, uint32_t, uint32_t, uint32_t); |
| if (fIsOpaque || kUnpremul_SkAlphaType == dstAlphaType) { |
| packARGB = &SkPackARGB32NoCheck; |
| } else { |
| packARGB = &SkPremultiplyARGBInline; |
| } |
| |
| // Fill in the color table |
| uint32_t i = 0; |
| for (; i < numColorsToRead; i++) { |
| uint8_t blue = get_byte(cBuffer.get(), i*fBytesPerColor); |
| uint8_t green = get_byte(cBuffer.get(), i*fBytesPerColor + 1); |
| uint8_t red = get_byte(cBuffer.get(), i*fBytesPerColor + 2); |
| uint8_t alpha; |
| if (fIsOpaque) { |
| alpha = 0xFF; |
| } else { |
| alpha = get_byte(cBuffer.get(), i*fBytesPerColor + 3); |
| } |
| colorTable[i] = packARGB(alpha, red, green, blue); |
| } |
| |
| // To avoid segmentation faults on bad pixel data, fill the end of the |
| // color table with black. This is the same the behavior as the |
| // chromium decoder. |
| for (; i < maxColors; i++) { |
| colorTable[i] = SkPackARGB32NoCheck(0xFF, 0, 0, 0); |
| } |
| |
| // Set the color table |
| fColorTable.reset(new SkColorTable(colorTable, maxColors)); |
| } |
| |
| // Bmp-in-Ico files do not use an offset to indicate where the pixel data |
| // begins. Pixel data always begins immediately after the color table. |
| if (!fInIco) { |
| // Check that we have not read past the pixel array offset |
| if(fOffset < colorBytes) { |
| // This may occur on OS 2.1 and other old versions where the color |
| // table defaults to max size, and the bmp tries to use a smaller |
| // color table. This is invalid, and our decision is to indicate |
| // an error, rather than try to guess the intended size of the |
| // color table. |
| SkCodecPrintf("Error: pixel data offset less than color table size.\n"); |
| return false; |
| } |
| |
| // After reading the color table, skip to the start of the pixel array |
| if (stream()->skip(fOffset - colorBytes) != fOffset - colorBytes) { |
| SkCodecPrintf("Error: unable to skip to image data.\n"); |
| return false; |
| } |
| } |
| |
| // Return true on success |
| return true; |
| } |
| |
| void SkBmpStandardCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& opts) { |
| // In the case of paletted ico-in-bmps, we will report BGRA to the client, |
| // since we may be required to apply an alpha mask after the decode. But |
| // the swizzler needs to know the actual format of the bmp. |
| SkEncodedInfo swizzlerInfo = this->getEncodedInfo(); |
| if (fInIco && this->bitsPerPixel() <= 8) { |
| swizzlerInfo = SkEncodedInfo::Make(SkEncodedInfo::kPalette_Color, swizzlerInfo.alpha(), |
| this->bitsPerPixel()); |
| } |
| |
| // Get a pointer to the color table if it exists |
| const SkPMColor* colorPtr = get_color_ptr(fColorTable.get()); |
| |
| // Create swizzler |
| fSwizzler.reset(SkSwizzler::CreateSwizzler(swizzlerInfo, colorPtr, dstInfo, opts)); |
| SkASSERT(fSwizzler); |
| } |
| |
| SkCodec::Result SkBmpStandardCodec::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(dstInfo.alphaType(), 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 swizzler |
| this->initializeSwizzler(dstInfo, options); |
| return SkCodec::kSuccess; |
| } |
| |
| /* |
| * Performs the bitmap decoding for standard input format |
| */ |
| int SkBmpStandardCodec::decodeRows(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, |
| const Options& opts) { |
| // Iterate over rows of the image |
| const int height = dstInfo.height(); |
| for (int y = 0; y < height; y++) { |
| // Read a row of the input |
| if (this->stream()->read(fSrcBuffer.get(), this->srcRowBytes()) != this->srcRowBytes()) { |
| SkCodecPrintf("Warning: incomplete input stream.\n"); |
| return y; |
| } |
| |
| // Decode the row in destination format |
| uint32_t row = this->getDstRow(y, dstInfo.height()); |
| |
| void* dstRow = SkTAddOffset<void>(dst, row * dstRowBytes); |
| fSwizzler->swizzle(dstRow, fSrcBuffer.get()); |
| } |
| |
| if (fInIco && fIsOpaque) { |
| const int startScanline = this->currScanline(); |
| if (startScanline < 0) { |
| // We are not performing a scanline decode. |
| // Just decode the entire ICO mask and return. |
| decodeIcoMask(this->stream(), dstInfo, dst, dstRowBytes); |
| return height; |
| } |
| |
| // In order to perform a scanline ICO decode, we must be able |
| // to skip ahead in the stream in order to apply the AND mask |
| // to the requested scanlines. |
| // We will do this by taking advantage of the fact that |
| // SkIcoCodec always uses a SkMemoryStream as its underlying |
| // representation of the stream. |
| const void* memoryBase = this->stream()->getMemoryBase(); |
| SkASSERT(nullptr != memoryBase); |
| SkASSERT(this->stream()->hasLength()); |
| SkASSERT(this->stream()->hasPosition()); |
| |
| const size_t length = this->stream()->getLength(); |
| const size_t currPosition = this->stream()->getPosition(); |
| |
| // Calculate how many bytes we must skip to reach the AND mask. |
| const int remainingScanlines = this->getInfo().height() - startScanline - height; |
| const size_t bytesToSkip = remainingScanlines * this->srcRowBytes() + |
| startScanline * fAndMaskRowBytes; |
| const size_t subStreamStartPosition = currPosition + bytesToSkip; |
| if (subStreamStartPosition >= length) { |
| // FIXME: How can we indicate that this decode was actually incomplete? |
| return height; |
| } |
| |
| // Create a subStream to pass to decodeIcoMask(). It is useful to encapsulate |
| // the memory base into a stream in order to safely handle incomplete images |
| // without reading out of bounds memory. |
| const void* subStreamMemoryBase = SkTAddOffset<const void>(memoryBase, |
| subStreamStartPosition); |
| const size_t subStreamLength = length - subStreamStartPosition; |
| // This call does not transfer ownership of the subStreamMemoryBase. |
| SkMemoryStream subStream(subStreamMemoryBase, subStreamLength, false); |
| |
| // FIXME: If decodeIcoMask does not succeed, is there a way that we can |
| // indicate the decode was incomplete? |
| decodeIcoMask(&subStream, dstInfo, dst, dstRowBytes); |
| } |
| |
| return height; |
| } |
| |
| void SkBmpStandardCodec::decodeIcoMask(SkStream* stream, const SkImageInfo& dstInfo, |
| void* dst, size_t dstRowBytes) { |
| // BMP in ICO have transparency, so this cannot be 565, and this mask |
| // prevents us from using kIndex8. The below code depends on the output |
| // being an SkPMColor. |
| SkASSERT(dstInfo.colorType() == kN32_SkColorType); |
| |
| // If we are sampling, make sure that we only mask the sampled pixels. |
| // We do not need to worry about sampling in the y-dimension because that |
| // should be handled by SkSampledCodec. |
| const int sampleX = fSwizzler->sampleX(); |
| const int sampledWidth = get_scaled_dimension(this->getInfo().width(), sampleX); |
| const int srcStartX = get_start_coord(sampleX); |
| |
| |
| SkPMColor* dstPtr = (SkPMColor*) dst; |
| for (int y = 0; y < dstInfo.height(); y++) { |
| // The srcBuffer will at least be large enough |
| if (stream->read(fSrcBuffer.get(), fAndMaskRowBytes) != fAndMaskRowBytes) { |
| SkCodecPrintf("Warning: incomplete AND mask for bmp-in-ico.\n"); |
| return; |
| } |
| |
| int row = this->getDstRow(y, dstInfo.height()); |
| |
| SkPMColor* dstRow = |
| SkTAddOffset<SkPMColor>(dstPtr, row * dstRowBytes); |
| |
| int srcX = srcStartX; |
| for (int dstX = 0; dstX < sampledWidth; dstX++) { |
| int quotient; |
| int modulus; |
| SkTDivMod(srcX, 8, "ient, &modulus); |
| uint32_t shift = 7 - modulus; |
| uint32_t alphaBit = (fSrcBuffer.get()[quotient] >> shift) & 0x1; |
| dstRow[dstX] &= alphaBit - 1; |
| srcX += sampleX; |
| } |
| } |
| } |
| |
| uint32_t SkBmpStandardCodec::onGetFillValue(SkColorType colorType) const { |
| const SkPMColor* colorPtr = get_color_ptr(fColorTable.get()); |
| if (colorPtr) { |
| return get_color_table_fill_value(colorType, colorPtr, 0); |
| } |
| return INHERITED::onGetFillValue(colorType); |
| } |
