| /* |
| * 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 "src/codec/SkBmpRLECodec.h" |
| |
| #include "include/core/SkAlphaType.h" |
| #include "include/core/SkColor.h" |
| #include "include/core/SkColorPriv.h" |
| #include "include/core/SkImageInfo.h" |
| #include "include/core/SkSize.h" |
| #include "include/core/SkStream.h" |
| #include "include/private/SkColorData.h" |
| #include "include/private/SkEncodedInfo.h" |
| #include "include/private/SkMalloc.h" |
| #include "include/private/SkTemplates.h" |
| #include "src/codec/SkCodecPriv.h" |
| |
| #include <algorithm> |
| #include <cstring> |
| #include <memory> |
| #include <utility> |
| |
| /* |
| * Creates an instance of the decoder |
| * Called only by NewFromStream |
| */ |
| SkBmpRLECodec::SkBmpRLECodec(SkEncodedInfo&& info, |
| std::unique_ptr<SkStream> stream, |
| uint16_t bitsPerPixel, uint32_t numColors, |
| uint32_t bytesPerColor, uint32_t offset, |
| SkCodec::SkScanlineOrder rowOrder) |
| : INHERITED(std::move(info), std::move(stream), bitsPerPixel, rowOrder) |
| , fColorTable(nullptr) |
| , fNumColors(numColors) |
| , fBytesPerColor(bytesPerColor) |
| , fOffset(offset) |
| , fBytesBuffered(0) |
| , fCurrRLEByte(0) |
| , fSampleX(1) |
| {} |
| |
| /* |
| * Initiates the bitmap decode |
| */ |
| SkCodec::Result SkBmpRLECodec::onGetPixels(const SkImageInfo& dstInfo, |
| void* dst, size_t dstRowBytes, |
| const Options& opts, |
| int* rowsDecoded) { |
| if (opts.fSubset) { |
| // Subsets are not supported. |
| return kUnimplemented; |
| } |
| |
| Result result = this->prepareToDecode(dstInfo, opts); |
| if (kSuccess != result) { |
| return result; |
| } |
| |
| // Perform the decode |
| int rows = this->decodeRows(dstInfo, dst, dstRowBytes, opts); |
| if (rows != dstInfo.height()) { |
| // We set rowsDecoded equal to the height because the background has already |
| // been filled. RLE encodings sometimes skip pixels, so we always start by |
| // filling the background. |
| *rowsDecoded = dstInfo.height(); |
| return kIncompleteInput; |
| } |
| |
| return kSuccess; |
| } |
| |
| /* |
| * Process the color table for the bmp input |
| */ |
| bool SkBmpRLECodec::createColorTable(SkColorType dstColorType) { |
| // 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 : std::min(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; |
| } |
| |
| // Fill in the color table |
| PackColorProc packARGB = choose_pack_color_proc(false, dstColorType); |
| 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); |
| colorTable[i] = packARGB(0xFF, 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)); |
| } |
| |
| // 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 SkBmpRLECodec::initializeStreamBuffer() { |
| fBytesBuffered = this->stream()->read(fStreamBuffer, kBufferSize); |
| if (fBytesBuffered == 0) { |
| SkCodecPrintf("Error: could not read RLE image data.\n"); |
| return false; |
| } |
| fCurrRLEByte = 0; |
| return true; |
| } |
| |
| /* |
| * @return the number of bytes remaining in the stream buffer after |
| * attempting to read more bytes from the stream |
| */ |
| size_t SkBmpRLECodec::checkForMoreData() { |
| const size_t remainingBytes = fBytesBuffered - fCurrRLEByte; |
| uint8_t* buffer = fStreamBuffer; |
| |
| // We will be reusing the same buffer, starting over from the beginning. |
| // Move any remaining bytes to the start of the buffer. |
| // We use memmove() instead of memcpy() because there is risk that the dst |
| // and src memory will overlap in corrupt images. |
| memmove(buffer, SkTAddOffset<uint8_t>(buffer, fCurrRLEByte), remainingBytes); |
| |
| // Adjust the buffer ptr to the start of the unfilled data. |
| buffer += remainingBytes; |
| |
| // Try to read additional bytes from the stream. There are fCurrRLEByte |
| // bytes of additional space remaining in the buffer, assuming that we |
| // have already copied remainingBytes to the start of the buffer. |
| size_t additionalBytes = this->stream()->read(buffer, fCurrRLEByte); |
| |
| // Update counters and return the number of bytes we currently have |
| // available. We are at the start of the buffer again. |
| fCurrRLEByte = 0; |
| fBytesBuffered = remainingBytes + additionalBytes; |
| return fBytesBuffered; |
| } |
| |
| /* |
| * Set an RLE pixel using the color table |
| */ |
| void SkBmpRLECodec::setPixel(void* dst, size_t dstRowBytes, |
| const SkImageInfo& dstInfo, uint32_t x, uint32_t y, |
| uint8_t index) { |
| if (dst && is_coord_necessary(x, fSampleX, dstInfo.width())) { |
| // Set the row |
| uint32_t row = this->getDstRow(y, dstInfo.height()); |
| |
| // Set the pixel based on destination color type |
| const int dstX = get_dst_coord(x, fSampleX); |
| switch (dstInfo.colorType()) { |
| case kRGBA_8888_SkColorType: |
| case kBGRA_8888_SkColorType: { |
| SkPMColor* dstRow = SkTAddOffset<SkPMColor>(dst, row * (int) dstRowBytes); |
| dstRow[dstX] = fColorTable->operator[](index); |
| break; |
| } |
| case kRGB_565_SkColorType: { |
| uint16_t* dstRow = SkTAddOffset<uint16_t>(dst, row * (int) dstRowBytes); |
| dstRow[dstX] = SkPixel32ToPixel16(fColorTable->operator[](index)); |
| break; |
| } |
| default: |
| // This case should not be reached. We should catch an invalid |
| // color type when we check that the conversion is possible. |
| SkASSERT(false); |
| break; |
| } |
| } |
| } |
| |
| /* |
| * Set an RLE pixel from R, G, B values |
| */ |
| void SkBmpRLECodec::setRGBPixel(void* dst, size_t dstRowBytes, |
| const SkImageInfo& dstInfo, uint32_t x, |
| uint32_t y, uint8_t red, uint8_t green, |
| uint8_t blue) { |
| if (dst && is_coord_necessary(x, fSampleX, dstInfo.width())) { |
| // Set the row |
| uint32_t row = this->getDstRow(y, dstInfo.height()); |
| |
| // Set the pixel based on destination color type |
| const int dstX = get_dst_coord(x, fSampleX); |
| switch (dstInfo.colorType()) { |
| case kRGBA_8888_SkColorType: { |
| SkPMColor* dstRow = SkTAddOffset<SkPMColor>(dst, row * (int) dstRowBytes); |
| dstRow[dstX] = SkPackARGB_as_RGBA(0xFF, red, green, blue); |
| break; |
| } |
| case kBGRA_8888_SkColorType: { |
| SkPMColor* dstRow = SkTAddOffset<SkPMColor>(dst, row * (int) dstRowBytes); |
| dstRow[dstX] = SkPackARGB_as_BGRA(0xFF, red, green, blue); |
| break; |
| } |
| case kRGB_565_SkColorType: { |
| uint16_t* dstRow = SkTAddOffset<uint16_t>(dst, row * (int) dstRowBytes); |
| dstRow[dstX] = SkPack888ToRGB16(red, green, blue); |
| break; |
| } |
| default: |
| // This case should not be reached. We should catch an invalid |
| // color type when we check that the conversion is possible. |
| SkASSERT(false); |
| break; |
| } |
| } |
| } |
| |
| SkCodec::Result SkBmpRLECodec::onPrepareToDecode(const SkImageInfo& dstInfo, |
| const SkCodec::Options& options) { |
| // FIXME: Support subsets for scanline decodes. |
| if (options.fSubset) { |
| // Subsets are not supported. |
| return kUnimplemented; |
| } |
| |
| // Reset fSampleX. If it needs to be a value other than 1, it will get modified by |
| // the sampler. |
| fSampleX = 1; |
| fLinesToSkip = 0; |
| |
| SkColorType colorTableColorType = dstInfo.colorType(); |
| if (this->colorXform()) { |
| // Just set a known colorType for the colorTable. No need to actually transform |
| // the colors in the colorTable. |
| colorTableColorType = kBGRA_8888_SkColorType; |
| } |
| |
| // 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(colorTableColorType)) { |
| SkCodecPrintf("Error: could not create color table.\n"); |
| return SkCodec::kInvalidInput; |
| } |
| |
| // Initialize a buffer for encoded RLE data |
| if (!this->initializeStreamBuffer()) { |
| SkCodecPrintf("Error: cannot initialize stream buffer.\n"); |
| return SkCodec::kInvalidInput; |
| } |
| |
| return SkCodec::kSuccess; |
| } |
| |
| /* |
| * Performs the bitmap decoding for RLE input format |
| * RLE decoding is performed all at once, rather than a one row at a time |
| */ |
| int SkBmpRLECodec::decodeRows(const SkImageInfo& info, void* dst, size_t dstRowBytes, |
| const Options& opts) { |
| int height = info.height(); |
| |
| // Account for sampling. |
| SkImageInfo dstInfo = info.makeWH(this->fillWidth(), height); |
| |
| // Set the background as transparent. Then, if the RLE code skips pixels, |
| // the skipped pixels will be transparent. |
| if (dst) { |
| SkSampler::Fill(dstInfo, dst, dstRowBytes, opts.fZeroInitialized); |
| } |
| |
| // Adjust the height and the dst if the previous call to decodeRows() left us |
| // with lines that need to be skipped. |
| if (height > fLinesToSkip) { |
| height -= fLinesToSkip; |
| if (dst) { |
| dst = SkTAddOffset<void>(dst, fLinesToSkip * dstRowBytes); |
| } |
| fLinesToSkip = 0; |
| |
| dstInfo = dstInfo.makeWH(dstInfo.width(), height); |
| } else { |
| fLinesToSkip -= height; |
| return height; |
| } |
| |
| void* decodeDst = dst; |
| size_t decodeRowBytes = dstRowBytes; |
| SkImageInfo decodeInfo = dstInfo; |
| if (decodeDst) { |
| if (this->colorXform()) { |
| decodeInfo = decodeInfo.makeColorType(kXformSrcColorType); |
| if (kRGBA_F16_SkColorType == dstInfo.colorType()) { |
| int count = height * dstInfo.width(); |
| this->resetXformBuffer(count); |
| sk_bzero(this->xformBuffer(), count * sizeof(uint32_t)); |
| decodeDst = this->xformBuffer(); |
| decodeRowBytes = dstInfo.width() * sizeof(uint32_t); |
| } |
| } |
| } |
| |
| int decodedHeight = this->decodeRLE(decodeInfo, decodeDst, decodeRowBytes); |
| if (this->colorXform() && decodeDst) { |
| for (int y = 0; y < decodedHeight; y++) { |
| this->applyColorXform(dst, decodeDst, dstInfo.width()); |
| decodeDst = SkTAddOffset<void>(decodeDst, decodeRowBytes); |
| dst = SkTAddOffset<void>(dst, dstRowBytes); |
| } |
| } |
| |
| return decodedHeight; |
| } |
| |
| int SkBmpRLECodec::decodeRLE(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes) { |
| // Use the original width to count the number of pixels in each row. |
| const int width = this->dimensions().width(); |
| |
| // This tells us the number of rows that we are meant to decode. |
| const int height = dstInfo.height(); |
| |
| // Set RLE flags |
| constexpr uint8_t RLE_ESCAPE = 0; |
| constexpr uint8_t RLE_EOL = 0; |
| constexpr uint8_t RLE_EOF = 1; |
| constexpr uint8_t RLE_DELTA = 2; |
| |
| // Destination parameters |
| int x = 0; |
| int y = 0; |
| |
| while (true) { |
| // If we have reached a row that is beyond the requested height, we have |
| // succeeded. |
| if (y >= height) { |
| // It would be better to check for the EOF marker before indicating |
| // success, but we may be performing a scanline decode, which |
| // would require us to stop before decoding the full height. |
| return height; |
| } |
| |
| // Every entry takes at least two bytes |
| if ((int) fBytesBuffered - fCurrRLEByte < 2) { |
| if (this->checkForMoreData() < 2) { |
| return y; |
| } |
| } |
| |
| // Read the next two bytes. These bytes have different meanings |
| // depending on their values. In the first interpretation, the first |
| // byte is an escape flag and the second byte indicates what special |
| // task to perform. |
| const uint8_t flag = fStreamBuffer[fCurrRLEByte++]; |
| const uint8_t task = fStreamBuffer[fCurrRLEByte++]; |
| |
| // Perform decoding |
| if (RLE_ESCAPE == flag) { |
| switch (task) { |
| case RLE_EOL: |
| x = 0; |
| y++; |
| break; |
| case RLE_EOF: |
| return height; |
| case RLE_DELTA: { |
| // Two bytes are needed to specify delta |
| if ((int) fBytesBuffered - fCurrRLEByte < 2) { |
| if (this->checkForMoreData() < 2) { |
| return y; |
| } |
| } |
| // Modify x and y |
| const uint8_t dx = fStreamBuffer[fCurrRLEByte++]; |
| const uint8_t dy = fStreamBuffer[fCurrRLEByte++]; |
| x += dx; |
| y += dy; |
| if (x > width) { |
| SkCodecPrintf("Warning: invalid RLE input.\n"); |
| return y - dy; |
| } else if (y > height) { |
| fLinesToSkip = y - height; |
| return height; |
| } |
| break; |
| } |
| default: { |
| // If task does not match any of the above signals, it |
| // indicates that we have a sequence of non-RLE pixels. |
| // Furthermore, the value of task is equal to the number |
| // of pixels to interpret. |
| uint8_t numPixels = task; |
| const size_t rowBytes = compute_row_bytes(numPixels, |
| this->bitsPerPixel()); |
| if (x + numPixels > width) { |
| SkCodecPrintf("Warning: invalid RLE input.\n"); |
| } |
| |
| // Abort if there are not enough bytes |
| // remaining in the stream to set numPixels. |
| |
| // At most, alignedRowBytes can be 255 (max uint8_t) * |
| // 3 (max bytes per pixel) + 1 (aligned) = 766. If |
| // fStreamBuffer was smaller than this, |
| // checkForMoreData would never succeed for some bmps. |
| static_assert(255 * 3 + 1 < kBufferSize, |
| "kBufferSize needs to be larger!"); |
| const size_t alignedRowBytes = SkAlign2(rowBytes); |
| if ((int) fBytesBuffered - fCurrRLEByte < alignedRowBytes) { |
| SkASSERT(alignedRowBytes < kBufferSize); |
| if (this->checkForMoreData() < alignedRowBytes) { |
| return y; |
| } |
| } |
| // Set numPixels number of pixels |
| while ((numPixels > 0) && (x < width)) { |
| switch(this->bitsPerPixel()) { |
| case 4: { |
| SkASSERT(fCurrRLEByte < fBytesBuffered); |
| uint8_t val = fStreamBuffer[fCurrRLEByte++]; |
| setPixel(dst, dstRowBytes, dstInfo, x++, |
| y, val >> 4); |
| numPixels--; |
| if (numPixels != 0) { |
| setPixel(dst, dstRowBytes, dstInfo, |
| x++, y, val & 0xF); |
| numPixels--; |
| } |
| break; |
| } |
| case 8: |
| SkASSERT(fCurrRLEByte < fBytesBuffered); |
| setPixel(dst, dstRowBytes, dstInfo, x++, |
| y, fStreamBuffer[fCurrRLEByte++]); |
| numPixels--; |
| break; |
| case 24: { |
| SkASSERT(fCurrRLEByte + 2 < fBytesBuffered); |
| uint8_t blue = fStreamBuffer[fCurrRLEByte++]; |
| uint8_t green = fStreamBuffer[fCurrRLEByte++]; |
| uint8_t red = fStreamBuffer[fCurrRLEByte++]; |
| setRGBPixel(dst, dstRowBytes, dstInfo, |
| x++, y, red, green, blue); |
| numPixels--; |
| break; |
| } |
| default: |
| SkASSERT(false); |
| return y; |
| } |
| } |
| // Skip a byte if necessary to maintain alignment |
| if (!SkIsAlign2(rowBytes)) { |
| fCurrRLEByte++; |
| } |
| break; |
| } |
| } |
| } else { |
| // If the first byte read is not a flag, it indicates the number of |
| // pixels to set in RLE mode. |
| const uint8_t numPixels = flag; |
| const int endX = std::min<int>(x + numPixels, width); |
| |
| if (24 == this->bitsPerPixel()) { |
| // In RLE24, the second byte read is part of the pixel color. |
| // There are two more required bytes to finish encoding the |
| // color. |
| if ((int) fBytesBuffered - fCurrRLEByte < 2) { |
| if (this->checkForMoreData() < 2) { |
| return y; |
| } |
| } |
| |
| // Fill the pixels up to endX with the specified color |
| uint8_t blue = task; |
| uint8_t green = fStreamBuffer[fCurrRLEByte++]; |
| uint8_t red = fStreamBuffer[fCurrRLEByte++]; |
| while (x < endX) { |
| setRGBPixel(dst, dstRowBytes, dstInfo, x++, y, red, green, blue); |
| } |
| } else { |
| // In RLE8 or RLE4, the second byte read gives the index in the |
| // color table to look up the pixel color. |
| // RLE8 has one color index that gets repeated |
| // RLE4 has two color indexes in the upper and lower 4 bits of |
| // the bytes, which are alternated |
| uint8_t indices[2] = { task, task }; |
| if (4 == this->bitsPerPixel()) { |
| indices[0] >>= 4; |
| indices[1] &= 0xf; |
| } |
| |
| // Set the indicated number of pixels |
| for (int which = 0; x < endX; x++) { |
| setPixel(dst, dstRowBytes, dstInfo, x, y, indices[which]); |
| which = !which; |
| } |
| } |
| } |
| } |
| } |
| |
| bool SkBmpRLECodec::skipRows(int count) { |
| const SkImageInfo rowInfo = SkImageInfo::Make(this->dimensions().width(), count, |
| kN32_SkColorType, kUnpremul_SkAlphaType); |
| return count == this->decodeRows(rowInfo, nullptr, 0, this->options()); |
| } |
| |
| // FIXME: Make SkBmpRLECodec have no knowledge of sampling. |
| // Or it should do all sampling natively. |
| // It currently is a hybrid that needs to know what SkScaledCodec is doing. |
| class SkBmpRLESampler : public SkSampler { |
| public: |
| SkBmpRLESampler(SkBmpRLECodec* codec) |
| : fCodec(codec) |
| { |
| SkASSERT(fCodec); |
| } |
| |
| int fillWidth() const override { |
| return fCodec->fillWidth(); |
| } |
| |
| private: |
| int onSetSampleX(int sampleX) override { |
| return fCodec->setSampleX(sampleX); |
| } |
| |
| // Unowned pointer. fCodec will delete this class in its destructor. |
| SkBmpRLECodec* fCodec; |
| }; |
| |
| SkSampler* SkBmpRLECodec::getSampler(bool createIfNecessary) { |
| if (!fSampler && createIfNecessary) { |
| fSampler = std::make_unique<SkBmpRLESampler>(this); |
| } |
| |
| return fSampler.get(); |
| } |
| |
| int SkBmpRLECodec::setSampleX(int sampleX) { |
| fSampleX = sampleX; |
| return this->fillWidth(); |
| } |
| |
| int SkBmpRLECodec::fillWidth() const { |
| return get_scaled_dimension(this->dimensions().width(), fSampleX); |
| } |