| /* | |
| * 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(const SkImageInfo& info, SkStream* stream, | |
| uint16_t bitsPerPixel, uint32_t numColors, | |
| uint32_t bytesPerColor, uint32_t offset, | |
| SkCodec::SkScanlineOrder rowOrder, | |
| bool isOpaque, bool inIco) | |
| : INHERITED(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) { | |
| // Get swizzler configuration | |
| SkSwizzler::SrcConfig config = SkSwizzler::kUnknown; | |
| switch (this->bitsPerPixel()) { | |
| case 1: | |
| config = SkSwizzler::kIndex1; | |
| break; | |
| case 2: | |
| config = SkSwizzler::kIndex2; | |
| break; | |
| case 4: | |
| config = SkSwizzler::kIndex4; | |
| break; | |
| case 8: | |
| config = SkSwizzler::kIndex; | |
| break; | |
| case 24: | |
| config = SkSwizzler::kBGR; | |
| break; | |
| case 32: | |
| if (fIsOpaque) { | |
| config = SkSwizzler::kBGRX; | |
| } else { | |
| config = SkSwizzler::kBGRA; | |
| } | |
| break; | |
| default: | |
| SkASSERT(false); | |
| } | |
| // Get a pointer to the color table if it exists | |
| const SkPMColor* colorPtr = get_color_ptr(fColorTable.get()); | |
| // Create swizzler | |
| fSwizzler.reset(SkSwizzler::CreateSwizzler(config, 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) { | |
| 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); | |
| } |