| /* |
| * 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 "SkCodecPriv.h" |
| #include "SkColorPriv.h" |
| #include "SkData.h" |
| #include "SkIcoCodec.h" |
| #include "SkPngCodec.h" |
| #include "SkStream.h" |
| #include "SkTDArray.h" |
| #include "SkTSort.h" |
| |
| /* |
| * 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(); |
| |
| // 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; |
| } |
| |
| int index = 0; |
| SkCodec::Result result = kInvalidScale; |
| while (true) { |
| index = this->chooseCodec(dstInfo.dimensions(), index); |
| if (index < 0) { |
| break; |
| } |
| |
| SkCodec* embeddedCodec = fEmbeddedCodecs->operator[](index); |
| result = embeddedCodec->getPixels(dstInfo, 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 = dstInfo.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) { |
| int index = 0; |
| SkCodec::Result result = kInvalidScale; |
| while (true) { |
| index = this->chooseCodec(dstInfo.dimensions(), index); |
| if (index < 0) { |
| break; |
| } |
| |
| SkCodec* embeddedCodec = fEmbeddedCodecs->operator[](index); |
| result = embeddedCodec->startScanlineDecode(dstInfo, &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; |
| } |