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- /*
- * 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 "include/core/SkStream.h"
- #include "include/private/SkColorData.h"
- #include "src/codec/SkBmpStandardCodec.h"
- #include "src/codec/SkCodecPriv.h"
- #include "src/core/SkMathPriv.h"
- /*
- * Creates an instance of the decoder
- * Called only by NewFromStream
- */
- SkBmpStandardCodec::SkBmpStandardCodec(SkEncodedInfo&& info, std::unique_ptr<SkStream> stream,
- uint16_t bitsPerPixel, uint32_t numColors,
- uint32_t bytesPerColor, uint32_t offset,
- SkCodec::SkScanlineOrder rowOrder,
- bool isOpaque, bool inIco)
- : INHERITED(std::move(info), std::move(stream), bitsPerPixel, rowOrder)
- , fColorTable(nullptr)
- , fNumColors(numColors)
- , fBytesPerColor(bytesPerColor)
- , fOffset(offset)
- , fSwizzler(nullptr)
- , fIsOpaque(isOpaque)
- , fInIco(inIco)
- , fAndMaskRowBytes(fInIco ? SkAlign4(compute_row_bytes(this->dimensions().width(), 1)) : 0)
- {}
- /*
- * Initiates the bitmap decode
- */
- SkCodec::Result SkBmpStandardCodec::onGetPixels(const SkImageInfo& dstInfo,
- void* dst, size_t dstRowBytes,
- const Options& opts,
- int* rowsDecoded) {
- if (opts.fSubset) {
- // Subsets are not supported.
- return kUnimplemented;
- }
- if (dstInfo.dimensions() != this->dimensions()) {
- SkCodecPrintf("Error: scaling not supported.\n");
- return kInvalidScale;
- }
- Result result = this->prepareToDecode(dstInfo, opts);
- 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(SkColorType dstColorType, SkAlphaType dstAlphaType) {
- // 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();
- // 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;
- std::unique_ptr<uint8_t[]> cBuffer(new uint8_t[colorBytes]);
- if (stream()->read(cBuffer.get(), colorBytes) != colorBytes) {
- SkCodecPrintf("Error: unable to read color table.\n");
- return false;
- }
- SkColorType packColorType = dstColorType;
- SkAlphaType packAlphaType = dstAlphaType;
- if (this->colorXform()) {
- packColorType = kBGRA_8888_SkColorType;
- packAlphaType = kUnpremul_SkAlphaType;
- }
- // Choose the proper packing function
- bool isPremul = (kPremul_SkAlphaType == packAlphaType) && !fIsOpaque;
- PackColorProc packARGB = choose_pack_color_proc(isPremul, packColorType);
- // 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);
- }
- if (this->colorXform() && !this->xformOnDecode()) {
- this->applyColorXform(colorTable, colorTable, maxColors);
- }
- // 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;
- }
- static SkEncodedInfo make_info(SkEncodedInfo::Color color,
- SkEncodedInfo::Alpha alpha, int bitsPerPixel) {
- // This is just used for the swizzler, which does not need the width or height.
- return SkEncodedInfo::Make(0, 0, color, alpha, bitsPerPixel);
- }
- SkEncodedInfo SkBmpStandardCodec::swizzlerInfo() const {
- const auto& info = this->getEncodedInfo();
- if (fInIco) {
- if (this->bitsPerPixel() <= 8) {
- return make_info(SkEncodedInfo::kPalette_Color,
- info.alpha(), this->bitsPerPixel());
- }
- if (this->bitsPerPixel() == 24) {
- return make_info(SkEncodedInfo::kBGR_Color,
- SkEncodedInfo::kOpaque_Alpha, 8);
- }
- }
- return make_info(info.color(), info.alpha(), info.bitsPerComponent());
- }
- void SkBmpStandardCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& opts) {
- // In the case of bmp-in-icos, we will report BGRA to the client,
- // since we may be required to apply an alpha mask after the decode.
- // However, the swizzler needs to know the actual format of the bmp.
- SkEncodedInfo encodedInfo = this->swizzlerInfo();
- // Get a pointer to the color table if it exists
- const SkPMColor* colorPtr = get_color_ptr(fColorTable.get());
- SkImageInfo swizzlerInfo = dstInfo;
- SkCodec::Options swizzlerOptions = opts;
- if (this->colorXform()) {
- swizzlerInfo = swizzlerInfo.makeColorType(kXformSrcColorType);
- if (kPremul_SkAlphaType == dstInfo.alphaType()) {
- swizzlerInfo = swizzlerInfo.makeAlphaType(kUnpremul_SkAlphaType);
- }
- swizzlerOptions.fZeroInitialized = kNo_ZeroInitialized;
- }
- fSwizzler = SkSwizzler::Make(encodedInfo, colorPtr, swizzlerInfo, swizzlerOptions);
- SkASSERT(fSwizzler);
- }
- SkCodec::Result SkBmpStandardCodec::onPrepareToDecode(const SkImageInfo& dstInfo,
- const SkCodec::Options& options) {
- if (this->xformOnDecode()) {
- this->resetXformBuffer(dstInfo.width());
- }
- // 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.colorType(), dstInfo.alphaType())) {
- SkCodecPrintf("Error: could not create color table.\n");
- return SkCodec::kInvalidInput;
- }
- // 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(this->srcBuffer(), 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);
- if (this->xformOnDecode()) {
- SkASSERT(this->colorXform());
- fSwizzler->swizzle(this->xformBuffer(), this->srcBuffer());
- this->applyColorXform(dstRow, this->xformBuffer(), fSwizzler->swizzleWidth());
- } else {
- fSwizzler->swizzle(dstRow, this->srcBuffer());
- }
- }
- 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->dimensions().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. The below code depends
- // on the output being an SkPMColor.
- SkASSERT(kRGBA_8888_SkColorType == dstInfo.colorType() ||
- kBGRA_8888_SkColorType == dstInfo.colorType() ||
- kRGBA_F16_SkColorType == dstInfo.colorType());
- // 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->dimensions().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(this->srcBuffer(), fAndMaskRowBytes) != fAndMaskRowBytes) {
- SkCodecPrintf("Warning: incomplete AND mask for bmp-in-ico.\n");
- return;
- }
- auto applyMask = [dstInfo](void* dstRow, int x, uint64_t bit) {
- if (kRGBA_F16_SkColorType == dstInfo.colorType()) {
- uint64_t* dst64 = (uint64_t*) dstRow;
- dst64[x] &= bit - 1;
- } else {
- uint32_t* dst32 = (uint32_t*) dstRow;
- dst32[x] &= bit - 1;
- }
- };
- int row = this->getDstRow(y, dstInfo.height());
- void* 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;
- uint64_t alphaBit = (this->srcBuffer()[quotient] >> shift) & 0x1;
- applyMask(dstRow, dstX, alphaBit);
- srcX += sampleX;
- }
- }
- }
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