Revert of Refactor parsing and storage of SkGammas

src/core/SkColorSpace_Base.h

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkColorSpace_Base_DEFINED
 #define SkColorSpace_Base_DEFINED
 
 #include "SkColorSpace.h"
 #include "SkData.h"
 #include "SkTemplates.h"
 
-struct SkGammas : SkRefCnt {
-
-    // There are four possible representations for gamma curves.  kNone_Type is used
-    // as a placeholder until the struct is initialized.  It is not a valid value.
-    enum class Type : uint8_t {
-        kNone_Type,
-        kNamed_Type,
-        kValue_Type,
-        kTable_Type,
-        kParam_Type,
-    };
-
-    // Contains information for a gamma table.
-    struct Table {
-        int    fSize;
-        size_t fOffset;
-
-        const float* table(const SkGammas* base) const {
-            return SkTAddOffset<const float>(base, sizeof(SkGammas) + fOffset);
-        }
-    };
-
-    // Contains the parameters for a parametric curve.
-    struct Params {
-        //     Y = (aX + b)^g + c  for X >= d
-        //     Y = eX + f          otherwise
-        float                    fG;
-        float                    fA;
-        float                    fB;
-        float                    fC;
-        float                    fD;
-        float                    fE;
-        float                    fF;
-    };
-
-    // Contains the actual gamma curve information.  Should be interpreted
-    // based on the type of the gamma curve.
-    union Data {
-        Data()
-            : fTable{ 0, 0 }
-        {}
-
-        SkColorSpace::GammaNamed fNamed;
-        float                    fValue;
-        Table                    fTable;
-        size_t                   fParamOffset;
-
-        const Params& params(const SkGammas* base) const {
-            return *SkTAddOffset<const Params>(base, sizeof(SkGammas) + fParamOffset);
-        }
-    };
-
-    bool isNamed(int i) const {
-        SkASSERT(0 <= i && i < 3);
-        return (&fRedType)[i] == Type::kNamed_Type;
+struct SkGammaCurve {
+    bool isNamed() const {
+       bool result = (SkColorSpace::kNonStandard_GammaNamed != fNamed);
+       SkASSERT(!result || (0.0f == fValue));
+       SkASSERT(!result || (0 == fTableSize));
+       SkASSERT(!result || (0.0f == fG && 0.0f == fE));
+       return result;
     }
 
-    bool isValue(int i) const {
-        SkASSERT(0 <= i && i < 3);
-        return (&fRedType)[i] == Type::kValue_Type;
+    bool isValue() const {
+        bool result = (0.0f != fValue);
+        SkASSERT(!result || SkColorSpace::kNonStandard_GammaNamed == fNamed);
+        SkASSERT(!result || (0 == fTableSize));
+        SkASSERT(!result || (0.0f == fG && 0.0f == fE));
+        return result;
     }
 
-    bool isTable(int i) const {
-        SkASSERT(0 <= i && i < 3);
-        return (&fRedType)[i] == Type::kTable_Type;
+    bool isTable() const {
+        bool result = (0 != fTableSize);
+        SkASSERT(!result || SkColorSpace::kNonStandard_GammaNamed == fNamed);
+        SkASSERT(!result || (0.0f == fValue));
+        SkASSERT(!result || (0.0f == fG && 0.0f == fE));
+        SkASSERT(!result || fTable);
+        return result;
     }
 
-    bool isParametric(int i) const {
-        SkASSERT(0 <= i && i < 3);
-        return (&fRedType)[i] == Type::kParam_Type;
+    bool isParametric() const {
+        bool result = (0.0f != fG || 0.0f != fE);
+        SkASSERT(!result || SkColorSpace::kNonStandard_GammaNamed == fNamed);
+        SkASSERT(!result || (0.0f == fValue));
+        SkASSERT(!result || (0 == fTableSize));
+        return result;
     }
 
-    const Data& data(int i) const {
-        SkASSERT(0 <= i && i < 3);
-        return (&fRedData)[i];
+    // We have four different ways to represent gamma.
+    // (1) A known, named type:
+    SkColorSpace::GammaNamed fNamed;
+
+    // (2) A single value:
+    float                    fValue;
+
+    // (3) A lookup table:
+    uint32_t                 fTableSize;
+    std::unique_ptr<float[]> fTable;
+
+    // (4) Parameters for a curve:
+    //     Y = (aX + b)^g + c  for X >= d
+    //     Y = eX + f          otherwise
+    float                    fG;
+    float                    fA;
+    float                    fB;
+    float                    fC;
+    float                    fD;
+    float                    fE;
+    float                    fF;
+
+    SkGammaCurve()
+        : fNamed(SkColorSpace::kNonStandard_GammaNamed)
+        , fValue(0.0f)
+        , fTableSize(0)
+        , fTable(nullptr)
+        , fG(0.0f)
+        , fA(0.0f)
+        , fB(0.0f)
+        , fC(0.0f)
+        , fD(0.0f)
+        , fE(0.0f)
+        , fF(0.0f)
+    {}
+
+    bool quickEquals(const SkGammaCurve& that) const {
+        return (this->fNamed == that.fNamed) && (this->fValue == that.fValue) &&
+                (this->fTableSize == that.fTableSize) && (this->fTable == that.fTable) &&
+                (this->fG == that.fG) && (this->fA == that.fA) && (this->fB == that.fB) &&
+                (this->fC == that.fC) && (this->fD == that.fD) && (this->fE == that.fE) &&
+                (this->fF == that.fF);
+    }
+};
+
+struct SkGammas : public SkRefCnt {
+public:
+    static SkColorSpace::GammaNamed Named(SkGammaCurve curves[3]) {
+        if (SkColorSpace::kLinear_GammaNamed == curves[0].fNamed &&
+            SkColorSpace::kLinear_GammaNamed == curves[1].fNamed &&
+            SkColorSpace::kLinear_GammaNamed == curves[2].fNamed)
+        {
+            return SkColorSpace::kLinear_GammaNamed;
+        }
+
+        if (SkColorSpace::kSRGB_GammaNamed == curves[0].fNamed &&
+            SkColorSpace::kSRGB_GammaNamed == curves[1].fNamed &&
+            SkColorSpace::kSRGB_GammaNamed == curves[2].fNamed)
+        {
+            return SkColorSpace::kSRGB_GammaNamed;
+        }
+
+        if (SkColorSpace::k2Dot2Curve_GammaNamed == curves[0].fNamed &&
+            SkColorSpace::k2Dot2Curve_GammaNamed == curves[1].fNamed &&
+            SkColorSpace::k2Dot2Curve_GammaNamed == curves[2].fNamed)
+        {
+            return SkColorSpace::k2Dot2Curve_GammaNamed;
+        }
+
+        return SkColorSpace::kNonStandard_GammaNamed;
     }
 
-    const float* table(int i) const {
-        SkASSERT(isTable(i));
-        return (&fRedData)[i].fTable.table(this);
+    const SkGammaCurve& operator[](int i) const {
+        SkASSERT(0 <= i && i < 3);
+        return (&fRed)[i];
     }
 
-    const Params& params(int i) const {
-        SkASSERT(isParametric(i));
-        return (&fRedData)[i].params(this);
-    }
+    const SkGammaCurve fRed;
+    const SkGammaCurve fGreen;
+    const SkGammaCurve fBlue;
 
-    SkGammas()
-        : fRedType(Type::kNone_Type)
-        , fGreenType(Type::kNone_Type)
-        , fBlueType(Type::kNone_Type)
+    SkGammas(SkGammaCurve red, SkGammaCurve green, SkGammaCurve blue)
+        : fRed(std::move(red))
+        , fGreen(std::move(green))
+        , fBlue(std::move(blue))
     {}
 
-    // These fields should only be modified when initializing the struct.
-    Data fRedData;
-    Data fGreenData;
-    Data fBlueData;
-    Type fRedType;
-    Type fGreenType;
-    Type fBlueType;
+    SkGammas() {}
+
+    friend class SkColorSpace;
 };
 
 struct SkColorLookUpTable : public SkRefCnt {
     uint8_t                  fInputChannels;
     uint8_t                  fOutputChannels;
     uint8_t                  fGridPoints[3];
     std::unique_ptr<float[]> fTable;
 
     SkColorLookUpTable()
         : fInputChannels(0)
@@ skipping 17 matching lines @@
      *  Writes this object as an ICC profile.
      */
     sk_sp<SkData> writeToICC() const;
 
 private:
 
     static sk_sp<SkColorSpace> NewRGB(GammaNamed gammaNamed, const SkMatrix44& toXYZD50);
 
     SkColorSpace_Base(GammaNamed gammaNamed, const SkMatrix44& toXYZ, Named named);
 
-    SkColorSpace_Base(sk_sp<SkColorLookUpTable> colorLUT, GammaNamed gammaNamed,
-                      sk_sp<SkGammas> gammas, const SkMatrix44& toXYZ, sk_sp<SkData> profileData);
+    SkColorSpace_Base(sk_sp<SkColorLookUpTable> colorLUT, sk_sp<SkGammas> gammas,
+                      const SkMatrix44& toXYZ, sk_sp<SkData> profileData);
 
     sk_sp<SkColorLookUpTable> fColorLUT;
     sk_sp<SkGammas>           fGammas;
     sk_sp<SkData>             fProfileData;
 
     friend class SkColorSpace;
     friend class ColorSpaceXformTest;
     typedef SkColorSpace INHERITED;
 };
 
 static inline SkColorSpace_Base* as_CSB(SkColorSpace* colorSpace) {
     return static_cast<SkColorSpace_Base*>(colorSpace);
 }
 
 static inline const SkColorSpace_Base* as_CSB(const SkColorSpace* colorSpace) {
     return static_cast<const SkColorSpace_Base*>(colorSpace);
 }
 
 static inline SkColorSpace_Base* as_CSB(const sk_sp<SkColorSpace>& colorSpace) {
     return static_cast<SkColorSpace_Base*>(colorSpace.get());
 }
 
 #endif