/*
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* Copyright 2015 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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#ifndef SkJpegCodec_DEFINED
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#define SkJpegCodec_DEFINED
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#include "SkCodec.h"
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#include "SkImageInfo.h"
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#include "SkSwizzler.h"
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#include "SkStream.h"
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#include "SkTemplates.h"
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class JpegDecoderMgr;
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/*
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*
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* This class implements the decoding for jpeg images
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*
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*/
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class SkJpegCodec : public SkCodec {
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public:
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static bool IsJpeg(const void*, size_t);
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/*
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* Assumes IsJpeg was called and returned true
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* Takes ownership of the stream
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*/
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static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*);
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protected:
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/*
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* Recommend a set of destination dimensions given a requested scale
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*/
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SkISize onGetScaledDimensions(float desiredScale) const override;
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/*
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* Initiates the jpeg decode
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*/
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Result onGetPixels(const SkImageInfo& dstInfo, void* dst, size_t dstRowBytes, const Options&,
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int*) override;
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bool onQueryYUV8(SkYUVASizeInfo* sizeInfo, SkYUVColorSpace* colorSpace) const override;
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Result onGetYUV8Planes(const SkYUVASizeInfo& sizeInfo,
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void* planes[SkYUVASizeInfo::kMaxCount]) override;
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SkEncodedImageFormat onGetEncodedFormat() const override {
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return SkEncodedImageFormat::kJPEG;
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}
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bool onRewind() override;
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bool onDimensionsSupported(const SkISize&) override;
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bool conversionSupported(const SkImageInfo&, bool, bool) override;
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private:
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/*
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* Allows SkRawCodec to communicate the color profile from the exif data.
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*/
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static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*,
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std::unique_ptr<SkEncodedInfo::ICCProfile> defaultColorProfile);
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/*
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* Read enough of the stream to initialize the SkJpegCodec.
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* Returns a bool representing success or failure.
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*
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* @param codecOut
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* If this returns true, and codecOut was not nullptr,
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* codecOut will be set to a new SkJpegCodec.
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*
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* @param decoderMgrOut
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* If this returns true, and codecOut was nullptr,
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* decoderMgrOut must be non-nullptr and decoderMgrOut will be set to a new
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* JpegDecoderMgr pointer.
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*
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* @param stream
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* Deleted on failure.
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* codecOut will take ownership of it in the case where we created a codec.
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* Ownership is unchanged when we set decoderMgrOut.
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*
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* @param defaultColorProfile
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* If the jpeg does not have an embedded color profile, the image data should
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* be tagged with this color profile.
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*/
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static Result ReadHeader(SkStream* stream, SkCodec** codecOut,
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JpegDecoderMgr** decoderMgrOut,
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std::unique_ptr<SkEncodedInfo::ICCProfile> defaultColorProfile);
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/*
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* Creates an instance of the decoder
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* Called only by NewFromStream
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*
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* @param info contains properties of the encoded data
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* @param stream the encoded image data
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* @param decoderMgr holds decompress struct, src manager, and error manager
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* takes ownership
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*/
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SkJpegCodec(SkEncodedInfo&& info, std::unique_ptr<SkStream> stream,
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JpegDecoderMgr* decoderMgr, SkEncodedOrigin origin);
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void initializeSwizzler(const SkImageInfo& dstInfo, const Options& options,
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bool needsCMYKToRGB);
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void allocateStorage(const SkImageInfo& dstInfo);
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int readRows(const SkImageInfo& dstInfo, void* dst, size_t rowBytes, int count, const Options&);
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/*
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* Scanline decoding.
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*/
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SkSampler* getSampler(bool createIfNecessary) override;
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Result onStartScanlineDecode(const SkImageInfo& dstInfo,
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const Options& options) override;
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int onGetScanlines(void* dst, int count, size_t rowBytes) override;
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bool onSkipScanlines(int count) override;
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std::unique_ptr<JpegDecoderMgr> fDecoderMgr;
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// We will save the state of the decompress struct after reading the header.
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// This allows us to safely call onGetScaledDimensions() at any time.
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const int fReadyState;
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SkAutoTMalloc<uint8_t> fStorage;
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uint8_t* fSwizzleSrcRow;
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uint32_t* fColorXformSrcRow;
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// libjpeg-turbo provides some subsetting. In the case that libjpeg-turbo
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// cannot take the exact the subset that we need, we will use the swizzler
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// to further subset the output from libjpeg-turbo.
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SkIRect fSwizzlerSubset;
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std::unique_ptr<SkSwizzler> fSwizzler;
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friend class SkRawCodec;
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typedef SkCodec INHERITED;
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};
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#endif
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