| /* |
| * 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 "SkScanlineDecoder.h" |
| #include "SkStream.h" |
| |
| /* |
| * Checks if the conversion between the input image and the requested output |
| * image has been implemented |
| */ |
| static bool conversion_possible(const SkImageInfo& dst, |
| const SkImageInfo& src) { |
| // Ensure that the profile type is unchanged |
| if (dst.profileType() != src.profileType()) { |
| return false; |
| } |
| |
| // Ensure the alpha type is valid |
| if (!valid_alpha(dst.alphaType(), src.alphaType())) { |
| return false; |
| } |
| |
| // Check for supported color types |
| switch (dst.colorType()) { |
| // Allow output to kN32 from any type of input |
| case kN32_SkColorType: |
| return true; |
| // Allow output to kIndex_8 from compatible inputs |
| case kIndex_8_SkColorType: |
| return kIndex_8_SkColorType == src.colorType(); |
| default: |
| return false; |
| } |
| } |
| |
| /* |
| * 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, |
| SkBmpCodec::RowOrder rowOrder, bool inIco) |
| : INHERITED(info, stream, bitsPerPixel, rowOrder) |
| , fColorTable(NULL) |
| , fNumColors(this->computeNumColors(numColors)) |
| , fBytesPerColor(bytesPerColor) |
| , fOffset(offset) |
| , fSwizzler(NULL) |
| , fSrcBuffer(NULL) |
| , fInIco(inIco) |
| {} |
| |
| /* |
| * Initiates the bitmap decode |
| */ |
| SkCodec::Result SkBmpStandardCodec::onGetPixels(const SkImageInfo& dstInfo, |
| void* dst, size_t dstRowBytes, |
| const Options& opts, |
| SkPMColor* inputColorPtr, |
| int* inputColorCount) { |
| if (!this->rewindIfNeeded()) { |
| return kCouldNotRewind; |
| } |
| 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; |
| } |
| |
| // 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 kInvalidInput; |
| } |
| |
| // Copy the color table to the client if necessary |
| copy_color_table(dstInfo, fColorTable, inputColorPtr, inputColorCount); |
| |
| // Initialize a swizzler if necessary |
| if (!this->initializeSwizzler(dstInfo, opts)) { |
| SkCodecPrintf("Error: cannot initialize swizzler.\n"); |
| return kInvalidConversion; |
| } |
| |
| return this->decode(dstInfo, dst, dstRowBytes, opts); |
| } |
| |
| /* |
| * Process the color table for the bmp input |
| */ |
| bool SkBmpStandardCodec::createColorTable(SkAlphaType alphaType, 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 (NULL != 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; |
| } |
| |
| // Read the color table from the stream |
| colorBytes = fNumColors * fBytesPerColor; |
| SkAutoTDeleteArray<uint8_t> cBuffer(SkNEW_ARRAY(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); |
| switch (alphaType) { |
| case kOpaque_SkAlphaType: |
| case kUnpremul_SkAlphaType: |
| packARGB = &SkPackARGB32NoCheck; |
| break; |
| case kPremul_SkAlphaType: |
| packARGB = &SkPreMultiplyARGB; |
| break; |
| default: |
| // This should not be reached because conversion possible |
| // should fail if the alpha type is not one of the above |
| // values. |
| SkASSERT(false); |
| packARGB = NULL; |
| break; |
| } |
| |
| // Fill in the color table |
| uint32_t i = 0; |
| for (; i < fNumColors; 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 (kOpaque_SkAlphaType == alphaType) { |
| 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(SkNEW_ARGS(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; |
| } |
| |
| bool SkBmpStandardCodec::initializeSwizzler(const SkImageInfo& dstInfo, |
| const Options& opts) { |
| // Allocate space for a row buffer |
| const size_t rowBytes = SkAlign4(compute_row_bytes(dstInfo.width(), this->bitsPerPixel())); |
| fSrcBuffer.reset(SkNEW_ARRAY(uint8_t, rowBytes)); |
| |
| // Get swizzler configuration |
| SkSwizzler::SrcConfig config; |
| 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 (kOpaque_SkAlphaType == dstInfo.alphaType()) { |
| config = SkSwizzler::kBGRX; |
| } else { |
| config = SkSwizzler::kBGRA; |
| } |
| break; |
| default: |
| SkASSERT(false); |
| return 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.fZeroInitialized, this->getInfo())); |
| |
| if (NULL == fSwizzler.get()) { |
| return false; |
| } |
| return true; |
| } |
| |
| /* |
| * Choose a fill for failures due to an incomplete image. We will use zero as |
| * the default palette index, black for opaque images, and transparent for |
| * non-opaque images. |
| */ |
| static uint32_t get_fill_color_or_index(uint16_t bitsPerPixels, SkAlphaType alphaType) { |
| uint32_t fillColorOrIndex; |
| switch (bitsPerPixels) { |
| case 1: |
| case 2: |
| case 4: |
| case 8: |
| fillColorOrIndex = 0; |
| break; |
| case 24: |
| fillColorOrIndex = SK_ColorBLACK; |
| break; |
| case 32: |
| if (kOpaque_SkAlphaType == alphaType) { |
| fillColorOrIndex = SK_ColorBLACK; |
| } else { |
| fillColorOrIndex = SK_ColorTRANSPARENT; |
| } |
| break; |
| default: |
| SkASSERT(false); |
| return 0; |
| } |
| return fillColorOrIndex; |
| } |
| |
| /* |
| * Performs the bitmap decoding for standard input format |
| */ |
| SkCodec::Result SkBmpStandardCodec::decode(const SkImageInfo& dstInfo, |
| void* dst, size_t dstRowBytes, |
| const Options& opts) { |
| // Set constant values |
| const int width = dstInfo.width(); |
| const int height = dstInfo.height(); |
| const size_t rowBytes = SkAlign4(compute_row_bytes(width, this->bitsPerPixel())); |
| |
| // Iterate over rows of the image |
| for (int y = 0; y < height; y++) { |
| // Read a row of the input |
| if (this->stream()->read(fSrcBuffer.get(), rowBytes) != rowBytes) { |
| SkCodecPrintf("Warning: incomplete input stream.\n"); |
| // Fill the destination image on failure |
| // Get the fill color/index and check if it is 0 |
| uint32_t fillColorOrIndex = get_fill_color_or_index(this->bitsPerPixel(), |
| dstInfo.alphaType()); |
| bool zeroFill = (0 == fillColorOrIndex); |
| |
| if (kNo_ZeroInitialized == opts.fZeroInitialized || !zeroFill) { |
| // Get a pointer to the color table if it exists |
| const SkPMColor* colorPtr = get_color_ptr(fColorTable.get()); |
| |
| void* dstStart = this->getDstStartRow(dst, dstRowBytes, y); |
| SkSwizzler::Fill(dstStart, dstInfo, dstRowBytes, dstInfo.height() - y, |
| fillColorOrIndex, colorPtr); |
| } |
| return kIncompleteInput; |
| } |
| |
| // Decode the row in destination format |
| uint32_t row; |
| if (SkBmpCodec::kTopDown_RowOrder == this->rowOrder()) { |
| row = y; |
| } else { |
| row = height - 1 - y; |
| } |
| |
| void* dstRow = SkTAddOffset<void>(dst, row * dstRowBytes); |
| fSwizzler->swizzle(dstRow, fSrcBuffer.get()); |
| } |
| |
| // Finally, apply the AND mask for bmp-in-ico images |
| if (fInIco) { |
| // The AND mask is always 1 bit per pixel |
| const size_t rowBytes = SkAlign4(compute_row_bytes(width, 1)); |
| |
| SkPMColor* dstPtr = (SkPMColor*) dst; |
| for (int y = 0; y < height; y++) { |
| // The srcBuffer will at least be large enough |
| if (stream()->read(fSrcBuffer.get(), rowBytes) != rowBytes) { |
| SkCodecPrintf("Warning: incomplete AND mask for bmp-in-ico.\n"); |
| return kIncompleteInput; |
| } |
| |
| int row; |
| if (SkBmpCodec::kBottomUp_RowOrder == this->rowOrder()) { |
| row = height - y - 1; |
| } else { |
| row = y; |
| } |
| |
| SkPMColor* dstRow = |
| SkTAddOffset<SkPMColor>(dstPtr, row * dstRowBytes); |
| |
| for (int x = 0; x < width; x++) { |
| int quotient; |
| int modulus; |
| SkTDivMod(x, 8, "ient, &modulus); |
| uint32_t shift = 7 - modulus; |
| uint32_t alphaBit = |
| (fSrcBuffer.get()[quotient] >> shift) & 0x1; |
| dstRow[x] &= alphaBit - 1; |
| } |
| } |
| } |
| |
| // Finished decoding the entire image |
| return kSuccess; |
| } |
