Rename SkGifCodec, SkIcoCodec, SkWbmpCodec

BUG=skia:
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1567863003

Review URL: https://codereview.chromium.org/1567863003

1 files changed, 378 insertions, 0 deletions

diff --git a/src/codec/SkIcoCodec.cpp b/src/codec/SkIcoCodec.cpp
new file mode 100644
index 0000000000..0280be304c
--- /dev/null
+++ b/src/codec/SkIcoCodec.cpp
@@ -0,0 +1,378 @@
+/*
+ * 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 "SkBmpCodec.h"
+#include "SkCodec_libpng.h"
+#include "SkCodecPriv.h"
+#include "SkColorPriv.h"
+#include "SkData.h"
+#include "SkIcoCodec.h"
+#include "SkStream.h"
+#include "SkTDArray.h"
+#include "SkTSort.h"
+
+static bool ico_conversion_possible(const SkImageInfo& dstInfo) {
+    // We only support kN32_SkColorType.
+    // This makes sense for BMP-in-ICO.  The presence of an AND
+    // mask (which changes colors and adds transparency) means that
+    // we cannot use k565 or kIndex8.
+    // FIXME: For PNG-in-ICO, we could technically support whichever
+    //        color types that the png supports.
+    if (kN32_SkColorType != dstInfo.colorType()) {
+        return false;
+    }
+
+    // We only support transparent alpha types.  This is necessary for
+    // BMP-in-ICOs since there will be an AND mask.
+    // FIXME: For opaque PNG-in-ICOs, we should be able to support kOpaque.
+    return kPremul_SkAlphaType == dstInfo.alphaType() ||
+            kUnpremul_SkAlphaType == dstInfo.alphaType();
+}
+
+static SkImageInfo fix_embedded_alpha(const SkImageInfo& dstInfo, SkAlphaType embeddedAlpha) {
+    // FIXME (msarett): ICO is considered non-opaque, even if the embedded BMP
+    // incorrectly claims it has no alpha.
+    switch (embeddedAlpha) {
+        case kPremul_SkAlphaType:
+        case kUnpremul_SkAlphaType:
+            // Use the requested alpha type if the embedded codec supports alpha.
+            embeddedAlpha = dstInfo.alphaType();
+            break;
+        case kOpaque_SkAlphaType:
+            // If the embedded codec claims it is opaque, decode as if it is opaque.
+            break;
+        default:
+            SkASSERT(false);
+            break;
+    }
+    return dstInfo.makeAlphaType(embeddedAlpha);
+}
+
+/*
+ * Checks the start of the stream to see if the image is an Ico or Cur
+ */
+bool SkIcoCodec::IsIco(const void* buffer, size_t bytesRead) {
+    const char icoSig[] = { '\x00', '\x00', '\x01', '\x00' };
+    const char curSig[] = { '\x00', '\x00', '\x02', '\x00' };
+    return bytesRead >= sizeof(icoSig) &&
+            (!memcmp(buffer, icoSig, sizeof(icoSig)) ||
+            !memcmp(buffer, curSig, sizeof(curSig)));
+}
+
+/*
+ * Assumes IsIco was called and returned true
+ * Creates an Ico decoder
+ * Reads enough of the stream to determine the image format
+ */
+SkCodec* SkIcoCodec::NewFromStream(SkStream* stream) {
+    // Ensure that we do not leak the input stream
+    SkAutoTDelete<SkStream> inputStream(stream);
+
+    // Header size constants
+    static const uint32_t kIcoDirectoryBytes = 6;
+    static const uint32_t kIcoDirEntryBytes = 16;
+
+    // Read the directory header
+    SkAutoTDeleteArray<uint8_t> dirBuffer(new uint8_t[kIcoDirectoryBytes]);
+    if (inputStream.get()->read(dirBuffer.get(), kIcoDirectoryBytes) !=
+            kIcoDirectoryBytes) {
+        SkCodecPrintf("Error: unable to read ico directory header.\n");
+        return nullptr;
+    }
+
+    // Process the directory header
+    const uint16_t numImages = get_short(dirBuffer.get(), 4);
+    if (0 == numImages) {
+        SkCodecPrintf("Error: No images embedded in ico.\n");
+        return nullptr;
+    }
+
+    // Ensure that we can read all of indicated directory entries
+    SkAutoTDeleteArray<uint8_t> entryBuffer(new uint8_t[numImages * kIcoDirEntryBytes]);
+    if (inputStream.get()->read(entryBuffer.get(), numImages*kIcoDirEntryBytes) !=
+            numImages*kIcoDirEntryBytes) {
+        SkCodecPrintf("Error: unable to read ico directory entries.\n");
+        return nullptr;
+    }
+
+    // This structure is used to represent the vital information about entries
+    // in the directory header.  We will obtain this information for each
+    // directory entry.
+    struct Entry {
+        uint32_t offset;
+        uint32_t size;
+    };
+    SkAutoTDeleteArray<Entry> directoryEntries(new Entry[numImages]);
+
+    // Iterate over directory entries
+    for (uint32_t i = 0; i < numImages; i++) {
+        // The directory entry contains information such as width, height,
+        // bits per pixel, and number of colors in the color palette.  We will
+        // ignore these fields since they are repeated in the header of the
+        // embedded image.  In the event of an inconsistency, we would always
+        // defer to the value in the embedded header anyway.
+
+        // Specifies the size of the embedded image, including the header
+        uint32_t size = get_int(entryBuffer.get(), 8 + i*kIcoDirEntryBytes);
+
+        // Specifies the offset of the embedded image from the start of file.
+        // It does not indicate the start of the pixel data, but rather the
+        // start of the embedded image header.
+        uint32_t offset = get_int(entryBuffer.get(), 12 + i*kIcoDirEntryBytes);
+
+        // Save the vital fields
+        directoryEntries.get()[i].offset = offset;
+        directoryEntries.get()[i].size = size;
+    }
+
+    // It is "customary" that the embedded images will be stored in order of
+    // increasing offset.  However, the specification does not indicate that
+    // they must be stored in this order, so we will not trust that this is the
+    // case.  Here we sort the embedded images by increasing offset.
+    struct EntryLessThan {
+        bool operator() (Entry a, Entry b) const {
+            return a.offset < b.offset;
+        }
+    };
+    EntryLessThan lessThan;
+    SkTQSort(directoryEntries.get(), directoryEntries.get() + numImages - 1,
+            lessThan);
+
+    // Now will construct a candidate codec for each of the embedded images
+    uint32_t bytesRead = kIcoDirectoryBytes + numImages * kIcoDirEntryBytes;
+    SkAutoTDelete<SkTArray<SkAutoTDelete<SkCodec>, true>> codecs(
+            new (SkTArray<SkAutoTDelete<SkCodec>, true>)(numImages));
+    for (uint32_t i = 0; i < numImages; i++) {
+        uint32_t offset = directoryEntries.get()[i].offset;
+        uint32_t size = directoryEntries.get()[i].size;
+
+        // Ensure that the offset is valid
+        if (offset < bytesRead) {
+            SkCodecPrintf("Warning: invalid ico offset.\n");
+            continue;
+        }
+
+        // If we cannot skip, assume we have reached the end of the stream and
+        // stop trying to make codecs
+        if (inputStream.get()->skip(offset - bytesRead) != offset - bytesRead) {
+            SkCodecPrintf("Warning: could not skip to ico offset.\n");
+            break;
+        }
+        bytesRead = offset;
+
+        // Create a new stream for the embedded codec
+        SkAutoTUnref<SkData> data(
+                SkData::NewFromStream(inputStream.get(), size));
+        if (nullptr == data.get()) {
+            SkCodecPrintf("Warning: could not create embedded stream.\n");
+            break;
+        }
+        SkAutoTDelete<SkMemoryStream> embeddedStream(new SkMemoryStream(data.get()));
+        bytesRead += size;
+
+        // Check if the embedded codec is bmp or png and create the codec
+        SkCodec* codec = nullptr;
+        if (SkPngCodec::IsPng((const char*) data->bytes(), data->size())) {
+            codec = SkPngCodec::NewFromStream(embeddedStream.detach());
+        } else {
+            codec = SkBmpCodec::NewFromIco(embeddedStream.detach());
+        }
+
+        // Save a valid codec
+        if (nullptr != codec) {
+            codecs->push_back().reset(codec);
+        }
+    }
+
+    // Recognize if there are no valid codecs
+    if (0 == codecs->count()) {
+        SkCodecPrintf("Error: could not find any valid embedded ico codecs.\n");
+        return nullptr;
+    }
+
+    // Use the largest codec as a "suggestion" for image info
+    uint32_t maxSize = 0;
+    uint32_t maxIndex = 0;
+    for (int32_t i = 0; i < codecs->count(); i++) {
+        SkImageInfo info = codecs->operator[](i)->getInfo();
+        uint32_t size = info.width() * info.height();
+        if (size > maxSize) {
+            maxSize = size;
+            maxIndex = i;
+        }
+    }
+    SkImageInfo info = codecs->operator[](maxIndex)->getInfo();
+
+    // ICOs contain an alpha mask after the image which means we cannot
+    // guarantee that an image is opaque, even if the sub-codec thinks it
+    // is.
+    // FIXME (msarett): The BMP decoder depends on the alpha type in order
+    // to decode correctly, otherwise it could report kUnpremul and we would
+    // not have to correct it here. Is there a better way?
+    // FIXME (msarett): This is only true for BMP in ICO - could a PNG in ICO
+    // be opaque? Is it okay that we missed out on the opportunity to mark
+    // such an image as opaque?
+    info = info.makeAlphaType(kUnpremul_SkAlphaType);
+
+    // Note that stream is owned by the embedded codec, the ico does not need
+    // direct access to the stream.
+    return new SkIcoCodec(info, codecs.detach());
+}
+
+/*
+ * Creates an instance of the decoder
+ * Called only by NewFromStream
+ */
+SkIcoCodec::SkIcoCodec(const SkImageInfo& info,
+                       SkTArray<SkAutoTDelete<SkCodec>, true>* codecs)
+    : INHERITED(info, nullptr)
+    , fEmbeddedCodecs(codecs)
+    , fCurrScanlineCodec(nullptr)
+{}
+
+/*
+ * Chooses the best dimensions given the desired scale
+ */
+SkISize SkIcoCodec::onGetScaledDimensions(float desiredScale) const { 
+    // We set the dimensions to the largest candidate image by default.
+    // Regardless of the scale request, this is the largest image that we
+    // will decode.
+    int origWidth = this->getInfo().width();
+    int origHeight = this->getInfo().height();
+    float desiredSize = desiredScale * origWidth * origHeight;
+    // At least one image will have smaller error than this initial value
+    float minError = ((float) (origWidth * origHeight)) - desiredSize + 1.0f;
+    int32_t minIndex = -1;
+    for (int32_t i = 0; i < fEmbeddedCodecs->count(); i++) {
+        int width = fEmbeddedCodecs->operator[](i)->getInfo().width();
+        int height = fEmbeddedCodecs->operator[](i)->getInfo().height();
+        float error = SkTAbs(((float) (width * height)) - desiredSize);
+        if (error < minError) {
+            minError = error;
+            minIndex = i;
+        }
+    }
+    SkASSERT(minIndex >= 0);
+
+    return fEmbeddedCodecs->operator[](minIndex)->getInfo().dimensions();
+}
+
+int SkIcoCodec::chooseCodec(const SkISize& requestedSize, int startIndex) {
+    SkASSERT(startIndex >= 0);
+
+    // FIXME: Cache the index from onGetScaledDimensions?
+    for (int i = startIndex; i < fEmbeddedCodecs->count(); i++) {
+        if (fEmbeddedCodecs->operator[](i)->getInfo().dimensions() == requestedSize) {
+            return i;
+        }
+    }
+
+    return -1;
+}
+
+bool SkIcoCodec::onDimensionsSupported(const SkISize& dim) {
+    return this->chooseCodec(dim, 0) >= 0;
+}
+
+/*
+ * Initiates the Ico decode
+ */
+SkCodec::Result SkIcoCodec::onGetPixels(const SkImageInfo& dstInfo,
+                                        void* dst, size_t dstRowBytes,
+                                        const Options& opts, SkPMColor* colorTable,
+                                        int* colorCount, int* rowsDecoded) {
+    if (opts.fSubset) {
+        // Subsets are not supported.
+        return kUnimplemented;
+    }
+
+    if (!ico_conversion_possible(dstInfo)) {
+        return kInvalidConversion;
+    }
+
+    int index = 0;
+    SkCodec::Result result = kInvalidScale;
+    while (true) {
+        index = this->chooseCodec(dstInfo.dimensions(), index);
+        if (index < 0) {
+            break;
+        }
+
+        SkCodec* embeddedCodec = fEmbeddedCodecs->operator[](index);
+        SkImageInfo decodeInfo = fix_embedded_alpha(dstInfo, embeddedCodec->getInfo().alphaType());
+        SkASSERT(decodeInfo.colorType() == kN32_SkColorType);
+        result = embeddedCodec->getPixels(decodeInfo, dst, dstRowBytes, &opts, colorTable,
+                colorCount);
+
+        switch (result) {
+            case kSuccess:
+            case kIncompleteInput:
+                // The embedded codec will handle filling incomplete images, so we will indicate
+                // that all of the rows are initialized.
+                *rowsDecoded = decodeInfo.height();
+                return result;
+            default:
+                // Continue trying to find a valid embedded codec on a failed decode.
+                break;
+        }
+
+        index++;
+    }
+
+    SkCodecPrintf("Error: No matching candidate image in ico.\n");
+    return result;
+}
+
+SkCodec::Result SkIcoCodec::onStartScanlineDecode(const SkImageInfo& dstInfo,
+        const SkCodec::Options& options, SkPMColor colorTable[], int* colorCount) {
+    if (!ico_conversion_possible(dstInfo)) {
+        return kInvalidConversion;
+    }
+
+    int index = 0;
+    SkCodec::Result result = kInvalidScale;
+    while (true) {
+        index = this->chooseCodec(dstInfo.dimensions(), index);
+        if (index < 0) {
+            break;
+        }
+
+        SkCodec* embeddedCodec = fEmbeddedCodecs->operator[](index);
+        SkImageInfo decodeInfo = fix_embedded_alpha(dstInfo, embeddedCodec->getInfo().alphaType());
+        result = embeddedCodec->startScanlineDecode(decodeInfo, &options, colorTable, colorCount);
+        if (kSuccess == result) {
+            fCurrScanlineCodec = embeddedCodec;
+            return result;
+        }
+
+        index++;
+    }
+
+    SkCodecPrintf("Error: No matching candidate image in ico.\n");
+    return result;
+}
+
+int SkIcoCodec::onGetScanlines(void* dst, int count, size_t rowBytes) {
+    SkASSERT(fCurrScanlineCodec);
+    return fCurrScanlineCodec->getScanlines(dst, count, rowBytes);
+}
+
+bool SkIcoCodec::onSkipScanlines(int count) {
+    SkASSERT(fCurrScanlineCodec);
+    return fCurrScanlineCodec->skipScanlines(count);
+}
+
+SkCodec::SkScanlineOrder SkIcoCodec::onGetScanlineOrder() const {
+    // FIXME: This function will possibly return the wrong value if it is called
+    //        before startScanlineDecode().
+    return fCurrScanlineCodec ? fCurrScanlineCodec->getScanlineOrder() :
+            INHERITED::onGetScanlineOrder();
+}
+
+SkSampler* SkIcoCodec::getSampler(bool createIfNecessary) {
+    return fCurrScanlineCodec ? fCurrScanlineCodec->getSampler(createIfNecessary) : nullptr;
+}