/*
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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 SkPngCodec_DEFINED
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#define SkPngCodec_DEFINED
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#include "SkCodec.h"
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#include "SkColorTable.h"
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#include "SkPngChunkReader.h"
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#include "SkEncodedImageFormat.h"
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#include "SkImageInfo.h"
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#include "SkRefCnt.h"
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#include "SkSwizzler.h"
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class SkStream;
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class SkPngCodec : public SkCodec {
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public:
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static bool IsPng(const char*, size_t);
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// Assume IsPng was called and returned true.
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static std::unique_ptr<SkCodec> MakeFromStream(std::unique_ptr<SkStream>, Result*,
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SkPngChunkReader* = nullptr);
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// FIXME (scroggo): Temporarily needed by AutoCleanPng.
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void setIdatLength(size_t len) { fIdatLength = len; }
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~SkPngCodec() override;
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protected:
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// We hold the png_ptr and info_ptr as voidp to avoid having to include png.h
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// or forward declare their types here. voidp auto-casts to the real pointer types.
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struct voidp {
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voidp(void* ptr) : fPtr(ptr) {}
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template <typename T>
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operator T*() const { return (T*)fPtr; }
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explicit operator bool() const { return fPtr != nullptr; }
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void* fPtr;
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};
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SkPngCodec(SkEncodedInfo&&, std::unique_ptr<SkStream>, SkPngChunkReader*,
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void* png_ptr, void* info_ptr, int bitDepth);
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Result onGetPixels(const SkImageInfo&, void*, size_t, const Options&, int*)
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override;
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SkEncodedImageFormat onGetEncodedFormat() const override { return SkEncodedImageFormat::kPNG; }
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bool onRewind() override;
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SkSampler* getSampler(bool createIfNecessary) override;
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void applyXformRow(void* dst, const void* src);
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voidp png_ptr() { return fPng_ptr; }
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voidp info_ptr() { return fInfo_ptr; }
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SkSwizzler* swizzler() { return fSwizzler.get(); }
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// Initialize variables used by applyXformRow.
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void initializeXformParams();
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/**
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* Pass available input to libpng to process it.
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*
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* libpng will call any relevant callbacks installed. This will continue decoding
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* until it reaches the end of the file, or until a callback tells libpng to stop.
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*/
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bool processData();
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Result onStartIncrementalDecode(const SkImageInfo& dstInfo, void* pixels, size_t rowBytes,
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const SkCodec::Options&) override;
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Result onIncrementalDecode(int*) override;
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sk_sp<SkPngChunkReader> fPngChunkReader;
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voidp fPng_ptr;
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voidp fInfo_ptr;
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// These are stored here so they can be used both by normal decoding and scanline decoding.
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sk_sp<SkColorTable> fColorTable; // May be unpremul.
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std::unique_ptr<SkSwizzler> fSwizzler;
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SkAutoTMalloc<uint8_t> fStorage;
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void* fColorXformSrcRow;
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const int fBitDepth;
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private:
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enum XformMode {
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// Requires only a swizzle pass.
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kSwizzleOnly_XformMode,
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// Requires only a color xform pass.
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kColorOnly_XformMode,
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// Requires a swizzle and a color xform.
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kSwizzleColor_XformMode,
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};
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bool createColorTable(const SkImageInfo& dstInfo);
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// Helper to set up swizzler, color xforms, and color table. Also calls png_read_update_info.
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SkCodec::Result initializeXforms(const SkImageInfo& dstInfo, const Options&);
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void initializeSwizzler(const SkImageInfo& dstInfo, const Options&, bool skipFormatConversion);
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void allocateStorage(const SkImageInfo& dstInfo);
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void destroyReadStruct();
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virtual Result decodeAllRows(void* dst, size_t rowBytes, int* rowsDecoded) = 0;
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virtual void setRange(int firstRow, int lastRow, void* dst, size_t rowBytes) = 0;
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virtual Result decode(int* rowsDecoded) = 0;
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XformMode fXformMode;
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int fXformWidth;
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size_t fIdatLength;
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bool fDecodedIdat;
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typedef SkCodec INHERITED;
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};
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#endif // SkPngCodec_DEFINED
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