Rename SkGifCodec, SkIcoCodec, SkWbmpCodec

src/codec/SkCodec_libgif.cpp

Index: src/codec/SkCodec_libgif.cpp
diff --git a/src/codec/SkCodec_libgif.cpp b/src/codec/SkCodec_libgif.cpp
deleted file mode 100644
index 40ed94d0bb10df8ff57531793f376288a255fcfb..0000000000000000000000000000000000000000
--- a/src/codec/SkCodec_libgif.cpp
+++ /dev/null
@@ -1,590 +0,0 @@
-/*
- * 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 "SkCodec_libgif.h"
-#include "SkCodecPriv.h"
-#include "SkColorPriv.h"
-#include "SkColorTable.h"
-#include "SkStream.h"
-#include "SkSwizzler.h"
-#include "SkUtils.h"
-
-/*
- * Checks the start of the stream to see if the image is a gif
- */
-bool SkGifCodec::IsGif(const void* buf, size_t bytesRead) {
-    if (bytesRead >= GIF_STAMP_LEN) {
-        if (memcmp(GIF_STAMP,   buf, GIF_STAMP_LEN) == 0 ||
-            memcmp(GIF87_STAMP, buf, GIF_STAMP_LEN) == 0 ||
-            memcmp(GIF89_STAMP, buf, GIF_STAMP_LEN) == 0)
-        {
-            return true;
-        }
-    }
-    return false;
-}
-
-/*
- * Error function
- */
-static SkCodec::Result gif_error(const char* msg, SkCodec::Result result = SkCodec::kInvalidInput) {
-    SkCodecPrintf("Gif Error: %s\n", msg);
-    return result;
-}
-
-
-/*
- * Read function that will be passed to gif_lib
- */
-static int32_t read_bytes_callback(GifFileType* fileType, GifByteType* out, int32_t size) {
-    SkStream* stream = (SkStream*) fileType->UserData;
-    return (int32_t) stream->read(out, size);
-}
-
-/*
- * Open the gif file
- */
-static GifFileType* open_gif(SkStream* stream) {
-    return DGifOpen(stream, read_bytes_callback, nullptr);
-}
-
-/*
- * Check if a there is an index of the color table for a transparent pixel
- */
-static uint32_t find_trans_index(const SavedImage& image) {
-    // If there is a transparent index specified, it will be contained in an
-    // extension block.  We will loop through extension blocks in reverse order
-    // to check the most recent extension blocks first.
-    for (int32_t i = image.ExtensionBlockCount - 1; i >= 0; i--) {
-        // Get an extension block
-        const ExtensionBlock& extBlock = image.ExtensionBlocks[i];
-
-        // Specifically, we need to check for a graphics control extension,
-        // which may contain transparency information.  Also, note that a valid
-        // graphics control extension is always four bytes.  The fourth byte
-        // is the transparent index (if it exists), so we need at least four
-        // bytes.
-        if (GRAPHICS_EXT_FUNC_CODE == extBlock.Function && extBlock.ByteCount >= 4) {
-            // Check the transparent color flag which indicates whether a
-            // transparent index exists.  It is the least significant bit of
-            // the first byte of the extension block.
-            if (1 == (extBlock.Bytes[0] & 1)) {
-                // Use uint32_t to prevent sign extending
-                return extBlock.Bytes[3];
-            }
-
-            // There should only be one graphics control extension for the image frame
-            break;
-        }
-    }
-
-    // Use maximum unsigned int (surely an invalid index) to indicate that a valid
-    // index was not found.
-    return SK_MaxU32;
-}
-
-inline uint32_t ceil_div(uint32_t a, uint32_t b) {
-    return (a + b - 1) / b;
-}
-
-/*
- * Gets the output row corresponding to the encoded row for interlaced gifs
- */
-inline uint32_t get_output_row_interlaced(uint32_t encodedRow, uint32_t height) {
-    SkASSERT(encodedRow < height);
-    // First pass
-    if (encodedRow * 8 < height) {
-        return encodedRow * 8;
-    }
-    // Second pass
-    if (encodedRow * 4 < height) {
-        return 4 + 8 * (encodedRow - ceil_div(height, 8));
-    }
-    // Third pass
-    if (encodedRow * 2 < height) {
-        return 2 + 4 * (encodedRow - ceil_div(height, 4));
-    }
-    // Fourth pass
-    return 1 + 2 * (encodedRow - ceil_div(height, 2));
-}
-
-/*
- * This function cleans up the gif object after the decode completes
- * It is used in a SkAutoTCallIProc template
- */
-void SkGifCodec::CloseGif(GifFileType* gif) {
-    DGifCloseFile(gif, NULL);
-}
-
-/*
- * This function free extension data that has been saved to assist the image
- * decoder
- */
-void SkGifCodec::FreeExtension(SavedImage* image) {
-    if (NULL != image->ExtensionBlocks) {
-        GifFreeExtensions(&image->ExtensionBlockCount, &image->ExtensionBlocks);
-    }
-}
-
-/*
- * Read enough of the stream to initialize the SkGifCodec.
- * Returns a bool representing success or failure.
- *
- * @param codecOut
- * If it returned true, and codecOut was not nullptr,
- * codecOut will be set to a new SkGifCodec.
- *
- * @param gifOut
- * If it returned true, and codecOut was nullptr,
- * gifOut must be non-nullptr and gifOut will be set to a new
- * GifFileType pointer.
- *
- * @param stream
- * Deleted on failure.
- * codecOut will take ownership of it in the case where we created a codec.
- * Ownership is unchanged when we returned a gifOut.
- *
- */
-bool SkGifCodec::ReadHeader(SkStream* stream, SkCodec** codecOut, GifFileType** gifOut) {
-    SkAutoTDelete<SkStream> streamDeleter(stream);
-
-    // Read gif header, logical screen descriptor, and global color table
-    SkAutoTCallVProc<GifFileType, CloseGif> gif(open_gif(stream));
-
-    if (nullptr == gif) {
-        gif_error("DGifOpen failed.\n");
-        return false;
-    }
-
-    // Read through gif extensions to get to the image data.  Set the
-    // transparent index based on the extension data.
-    uint32_t transIndex;
-    SkCodec::Result result = ReadUpToFirstImage(gif, &transIndex);
-    if (kSuccess != result){
-        return false;
-    }
-
-    // Read the image descriptor
-    if (GIF_ERROR == DGifGetImageDesc(gif)) {
-        return false;
-    }
-    // If reading the image descriptor is successful, the image count will be
-    // incremented.
-    SkASSERT(gif->ImageCount >= 1);
-
-    if (nullptr != codecOut) {
-        SkISize size;
-        SkIRect frameRect;
-        if (!GetDimensions(gif, &size, &frameRect)) {
-            gif_error("Invalid gif size.\n");
-            return false;
-        }
-        bool frameIsSubset = (size != frameRect.size());
-
-        // Determine the recommended alpha type.  The transIndex might be valid if it less
-        // than 256.  We are not certain that the index is valid until we process the color
-        // table, since some gifs have color tables with less than 256 colors.  If
-        // there might be a valid transparent index, we must indicate that the image has
-        // alpha.
-        // In the case where we must support alpha, we have the option to set the
-        // suggested alpha type to kPremul or kUnpremul.  Both are valid since the alpha
-        // component will always be 0xFF or the entire 32-bit pixel will be set to zero.
-        // We prefer kPremul because we support kPremul, and it is more efficient to use
-        // kPremul directly even when kUnpremul is supported.
-        SkAlphaType alphaType = (transIndex < 256) ? kPremul_SkAlphaType : kOpaque_SkAlphaType;
-
-        // Return the codec
-        // kIndex is the most natural color type for gifs, so we set this as
-        // the default.
-        SkImageInfo imageInfo = SkImageInfo::Make(size.width(), size.height(), kIndex_8_SkColorType,
-                alphaType);
-        *codecOut = new SkGifCodec(imageInfo, streamDeleter.detach(), gif.detach(), transIndex,
-                frameRect, frameIsSubset);
-    } else {
-        SkASSERT(nullptr != gifOut);
-        streamDeleter.detach();
-        *gifOut = gif.detach();
-    }
-    return true;
-}
-
-/*
- * Assumes IsGif was called and returned true
- * Creates a gif decoder
- * Reads enough of the stream to determine the image format
- */
-SkCodec* SkGifCodec::NewFromStream(SkStream* stream) {
-    SkCodec* codec = nullptr;
-    if (ReadHeader(stream, &codec, nullptr)) {
-        return codec;
-    }
-    return nullptr;
-}
-
-SkGifCodec::SkGifCodec(const SkImageInfo& srcInfo, SkStream* stream, GifFileType* gif,
-        uint32_t transIndex, const SkIRect& frameRect, bool frameIsSubset)
-    : INHERITED(srcInfo, stream)
-    , fGif(gif)
-    , fSrcBuffer(new uint8_t[this->getInfo().width()])
-    , fFrameRect(frameRect)
-    // If it is valid, fTransIndex will be used to set fFillIndex.  We don't know if
-    // fTransIndex is valid until we process the color table, since fTransIndex may
-    // be greater than the size of the color table.
-    , fTransIndex(transIndex)
-    // Default fFillIndex is 0.  We will overwrite this if fTransIndex is valid, or if
-    // there is a valid background color.
-    , fFillIndex(0)
-    , fFrameIsSubset(frameIsSubset)
-    , fSwizzler(NULL)
-    , fColorTable(NULL)
-{}
-
-bool SkGifCodec::onRewind() {
-    GifFileType* gifOut = nullptr;
-    if (!ReadHeader(this->stream(), nullptr, &gifOut)) {
-        return false;
-    }
-
-    SkASSERT(nullptr != gifOut);
-    fGif.reset(gifOut);
-    return true;
-}
-
-SkCodec::Result SkGifCodec::ReadUpToFirstImage(GifFileType* gif, uint32_t* transIndex) {
-    // Use this as a container to hold information about any gif extension
-    // blocks.  This generally stores transparency and animation instructions.
-    SavedImage saveExt;
-    SkAutoTCallVProc<SavedImage, FreeExtension> autoFreeExt(&saveExt);
-    saveExt.ExtensionBlocks = nullptr;
-    saveExt.ExtensionBlockCount = 0;
-    GifByteType* extData;
-    int32_t extFunction;
-
-    // We will loop over components of gif images until we find an image.  Once
-    // we find an image, we will decode and return it.  While many gif files
-    // contain more than one image, we will simply decode the first image.
-    GifRecordType recordType;
-    do {
-        // Get the current record type
-        if (GIF_ERROR == DGifGetRecordType(gif, &recordType)) {
-            return gif_error("DGifGetRecordType failed.\n", kInvalidInput);
-        }
-        switch (recordType) {
-            case IMAGE_DESC_RECORD_TYPE: {
-                *transIndex = find_trans_index(saveExt);
-
-                // FIXME: Gif files may have multiple images stored in a single
-                //        file.  This is most commonly used to enable
-                //        animations.  Since we are leaving animated gifs as a
-                //        TODO, we will return kSuccess after decoding the
-                //        first image in the file.  This is the same behavior
-                //        as SkImageDecoder_libgif.
-                //
-                //        Most times this works pretty well, but sometimes it
-                //        doesn't.  For example, I have an animated test image
-                //        where the first image in the file is 1x1, but the
-                //        subsequent images are meaningful.  This currently
-                //        displays the 1x1 image, which is not ideal.  Right
-                //        now I am leaving this as an issue that will be
-                //        addressed when we implement animated gifs.
-                //
-                //        It is also possible (not explicitly disallowed in the
-                //        specification) that gif files provide multiple
-                //        images in a single file that are all meant to be
-                //        displayed in the same frame together.  I will
-                //        currently leave this unimplemented until I find a
-                //        test case that expects this behavior.
-                return kSuccess;
-            }
-            // Extensions are used to specify special properties of the image
-            // such as transparency or animation.
-            case EXTENSION_RECORD_TYPE:
-                // Read extension data
-                if (GIF_ERROR == DGifGetExtension(gif, &extFunction, &extData)) {
-                    return gif_error("Could not get extension.\n", kIncompleteInput);
-                }
-
-                // Create an extension block with our data
-                while (nullptr != extData) {
-                    // Add a single block
-                    if (GIF_ERROR == GifAddExtensionBlock(&saveExt.ExtensionBlockCount,
-                                                          &saveExt.ExtensionBlocks,
-                                                          extFunction, extData[0], &extData[1]))
-                    {
-                        return gif_error("Could not add extension block.\n", kIncompleteInput);
-                    }
-                    // Move to the next block
-                    if (GIF_ERROR == DGifGetExtensionNext(gif, &extData)) {
-                        return gif_error("Could not get next extension.\n", kIncompleteInput);
-                    }
-                }
-                break;
-
-            // Signals the end of the gif file
-            case TERMINATE_RECORD_TYPE:
-                break;
-
-            default:
-                // DGifGetRecordType returns an error if the record type does
-                // not match one of the above cases.  This should not be
-                // reached.
-                SkASSERT(false);
-                break;
-        }
-    } while (TERMINATE_RECORD_TYPE != recordType);
-
-    return gif_error("Could not find any images to decode in gif file.\n", kInvalidInput);
-}
-
-bool SkGifCodec::GetDimensions(GifFileType* gif, SkISize* size, SkIRect* frameRect) {
-    // Get the encoded dimension values
-    SavedImage* image = &gif->SavedImages[gif->ImageCount - 1];
-    const GifImageDesc& desc = image->ImageDesc;
-    int frameLeft = desc.Left;
-    int frameTop = desc.Top;
-    int frameWidth = desc.Width;
-    int frameHeight = desc.Height;
-    int width = gif->SWidth;
-    int height = gif->SHeight;
-
-    // Ensure that the decode dimensions are large enough to contain the frame
-    width = SkTMax(width, frameWidth + frameLeft);
-    height = SkTMax(height, frameHeight + frameTop);
-
-    // All of these dimensions should be positive, as they are encoded as unsigned 16-bit integers.
-    // It is unclear why giflib casts them to ints.  We will go ahead and check that they are
-    // in fact positive.
-    if (frameLeft < 0 || frameTop < 0 || frameWidth < 0 || frameHeight < 0 || width <= 0 ||
-            height <= 0) {
-        return false;
-    }
-
-    frameRect->setXYWH(frameLeft, frameTop, frameWidth, frameHeight);
-    size->set(width, height);
-    return true;
-}
-
-void SkGifCodec::initializeColorTable(const SkImageInfo& dstInfo, SkPMColor* inputColorPtr,
-        int* inputColorCount) {
-    // Set up our own color table
-    const uint32_t maxColors = 256;
-    SkPMColor colorPtr[256];
-    if (NULL != inputColorCount) {
-        // 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.
-        *inputColorCount = maxColors;
-    }
-
-    // Get local color table
-    ColorMapObject* colorMap = fGif->Image.ColorMap;
-    // If there is no local color table, use the global color table
-    if (NULL == colorMap) {
-        colorMap = fGif->SColorMap;
-    }
-
-    uint32_t colorCount = 0;
-    if (NULL != colorMap) {
-        colorCount = colorMap->ColorCount;
-        // giflib guarantees these properties
-        SkASSERT(colorCount == (unsigned) (1 << (colorMap->BitsPerPixel)));
-        SkASSERT(colorCount <= 256);
-        for (uint32_t i = 0; i < colorCount; i++) {
-            colorPtr[i] = SkPackARGB32(0xFF, colorMap->Colors[i].Red,
-                    colorMap->Colors[i].Green, colorMap->Colors[i].Blue);
-        }
-    }
-
-    // Gifs have the option to specify the color at a single index of the color
-    // table as transparent.  If the transparent index is greater than the
-    // colorCount, we know that there is no valid transparent color in the color
-    // table.  If there is not valid transparent index, we will try to use the
-    // backgroundIndex as the fill index.  If the backgroundIndex is also not
-    // valid, we will let fFillIndex default to 0 (it is set to zero in the
-    // constructor).  This behavior is not specified but matches
-    // SkImageDecoder_libgif.
-    uint32_t backgroundIndex = fGif->SBackGroundColor;
-    if (fTransIndex < colorCount) {
-        colorPtr[fTransIndex] = SK_ColorTRANSPARENT;
-        fFillIndex = fTransIndex;
-    } else if (backgroundIndex < colorCount) {
-        fFillIndex = backgroundIndex;
-    }
-
-    // Fill in the color table for indices greater than color count.
-    // This allows for predictable, safe behavior.
-    for (uint32_t i = colorCount; i < maxColors; i++) {
-        colorPtr[i] = colorPtr[fFillIndex];
-    }
-
-    fColorTable.reset(new SkColorTable(colorPtr, maxColors));
-    copy_color_table(dstInfo, this->fColorTable, inputColorPtr, inputColorCount);
-}
-
-SkCodec::Result SkGifCodec::prepareToDecode(const SkImageInfo& dstInfo, SkPMColor* inputColorPtr,
-        int* inputColorCount, const Options& opts) {
-    // Check for valid input parameters
-    if (!conversion_possible(dstInfo, this->getInfo())) {
-        return gif_error("Cannot convert input type to output type.\n",
-                kInvalidConversion);
-    }
-
-    // Initialize color table and copy to the client if necessary
-    this->initializeColorTable(dstInfo, inputColorPtr, inputColorCount);
-
-    return this->initializeSwizzler(dstInfo, opts);
-}
-
-SkCodec::Result SkGifCodec::initializeSwizzler(const SkImageInfo& dstInfo, const Options& opts) {
-    const SkPMColor* colorPtr = get_color_ptr(fColorTable.get());
-    const SkIRect* frameRect = fFrameIsSubset ? &fFrameRect : nullptr;
-    fSwizzler.reset(SkSwizzler::CreateSwizzler(SkSwizzler::kIndex, colorPtr, dstInfo, opts,
-            frameRect));
-
-    if (nullptr != fSwizzler.get()) {
-        return kSuccess;
-    }
-    return kUnimplemented;
-}
-
-bool SkGifCodec::readRow() {
-    return GIF_ERROR != DGifGetLine(fGif, fSrcBuffer.get(), fFrameRect.width());
-}
-
-/*
- * Initiates the gif decode
- */
-SkCodec::Result SkGifCodec::onGetPixels(const SkImageInfo& dstInfo,
-                                        void* dst, size_t dstRowBytes,
-                                        const Options& opts,
-                                        SkPMColor* inputColorPtr,
-                                        int* inputColorCount,
-                                        int* rowsDecoded) {
-    Result result = this->prepareToDecode(dstInfo, inputColorPtr, inputColorCount, opts);
-    if (kSuccess != result) {
-        return result;
-    }
-
-    if (dstInfo.dimensions() != this->getInfo().dimensions()) {
-        return gif_error("Scaling not supported.\n", kInvalidScale);
-    }
-
-    // Initialize the swizzler
-    if (fFrameIsSubset) {
-        // Fill the background
-        SkSampler::Fill(dstInfo, dst, dstRowBytes,
-                this->getFillValue(dstInfo.colorType(), dstInfo.alphaType()),
-                opts.fZeroInitialized);
-    }
-
-    // Iterate over rows of the input
-    for (int y = fFrameRect.top(); y < fFrameRect.bottom(); y++) {
-        if (!this->readRow()) {
-            *rowsDecoded = y;
-            return gif_error("Could not decode line.\n", kIncompleteInput);
-        }
-        void* dstRow = SkTAddOffset<void>(dst, dstRowBytes * this->outputScanline(y));
-        fSwizzler->swizzle(dstRow, fSrcBuffer.get());
-    }
-    return kSuccess;
-}
-
-// FIXME: This is similar to the implementation for bmp and png.  Can we share more code or
-//        possibly make this non-virtual?
-uint32_t SkGifCodec::onGetFillValue(SkColorType colorType, SkAlphaType alphaType) const {
-    const SkPMColor* colorPtr = get_color_ptr(fColorTable.get());
-    return get_color_table_fill_value(colorType, colorPtr, fFillIndex);
-}
-
-SkCodec::Result SkGifCodec::onStartScanlineDecode(const SkImageInfo& dstInfo,
-        const SkCodec::Options& opts, SkPMColor inputColorPtr[], int* inputColorCount) {
-    return this->prepareToDecode(dstInfo, inputColorPtr, inputColorCount, this->options());
-}
-
-void SkGifCodec::handleScanlineFrame(int count, int* rowsBeforeFrame, int* rowsInFrame) {
-    if (fFrameIsSubset) {
-        const int currRow = this->currScanline();
-
-        // The number of rows that remain to be skipped before reaching rows that we
-        // actually must decode into.
-        // This must be at least zero.  We also make sure that it is less than or
-        // equal to count, since we will skip at most count rows.
-        *rowsBeforeFrame = SkTMin(count, SkTMax(0, fFrameRect.top() - currRow));
-
-        // Rows left to decode once we reach the start of the frame.
-        const int rowsLeft = count - *rowsBeforeFrame;
-
-        // Count the number of that extend beyond the bottom of the frame.  We do not
-        // need to decode into these rows.
-        const int rowsAfterFrame = SkTMax(0, currRow + rowsLeft - fFrameRect.bottom());
-
-        // Set the actual number of source rows that we need to decode.
-        *rowsInFrame = rowsLeft - rowsAfterFrame;
-    } else {
-        *rowsBeforeFrame = 0;
-        *rowsInFrame = count;
-    }
-}
-
-int SkGifCodec::onGetScanlines(void* dst, int count, size_t rowBytes) {
-    int rowsBeforeFrame;
-    int rowsInFrame;
-    this->handleScanlineFrame(count, &rowsBeforeFrame, &rowsInFrame);
-
-    if (fFrameIsSubset) {
-        // Fill the requested rows
-        SkImageInfo fillInfo = this->dstInfo().makeWH(this->dstInfo().width(), count);
-        uint32_t fillValue = this->onGetFillValue(this->dstInfo().colorType(),
-                this->dstInfo().alphaType());
-        fSwizzler->fill(fillInfo, dst, rowBytes, fillValue, this->options().fZeroInitialized);
-
-        // Start to write pixels at the start of the image frame
-        dst = SkTAddOffset<void>(dst, rowBytes * rowsBeforeFrame);
-    }
-
-    for (int i = 0; i < rowsInFrame; i++) {
-        if (!this->readRow()) {
-            return i + rowsBeforeFrame;
-        }
-        fSwizzler->swizzle(dst, fSrcBuffer.get());
-        dst = SkTAddOffset<void>(dst, rowBytes);
-    }
-
-    return count;
-}
-
-bool SkGifCodec::onSkipScanlines(int count) {
-    int rowsBeforeFrame;
-    int rowsInFrame;
-    this->handleScanlineFrame(count, &rowsBeforeFrame, &rowsInFrame);
-
-    for (int i = 0; i < rowsInFrame; i++) {
-        if (!this->readRow()) {
-            return false;
-        }
-    }
-
-    return true;
-}
-
-SkCodec::SkScanlineOrder SkGifCodec::onGetScanlineOrder() const {
-    if (fGif->Image.Interlace) {
-        return kOutOfOrder_SkScanlineOrder;
-    }
-    return kTopDown_SkScanlineOrder;
-}
-
-int SkGifCodec::onOutputScanline(int inputScanline) const {
-    if (fGif->Image.Interlace) {
-        if (inputScanline < fFrameRect.top() || inputScanline >= fFrameRect.bottom()) {
-            return inputScanline;
-        }
-        return get_output_row_interlaced(inputScanline - fFrameRect.top(), fFrameRect.height()) +
-                fFrameRect.top();
-    }
-    return inputScanline;
-}