content/smil/nsSMILValue.h

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #ifndef NS_SMILVALUE_H_
   7 #define NS_SMILVALUE_H_
   8
   9 #include "nsISMILType.h"
  10 #include "nsSMILNullType.h"
  11
  12 /**
  13  * Although objects of this type are generally only created on the stack and
  14  * only exist during the taking of a new time sample, that's not always the
  15  * case. The nsSMILValue objects obtained from attributes' base values are
  16  * cached so that the SMIL engine can make certain optimizations during a
  17  * sample if the base value has not changed since the last sample (potentially
  18  * avoiding recomposing). These nsSMILValue objects typically live much longer
  19  * than a single sample.
  20  */
  21 class nsSMILValue
  22 {
  23 public:
  24   nsSMILValue() : mU(), mType(nsSMILNullType::Singleton()) { }
  25   explicit nsSMILValue(const nsISMILType* aType);
  26   nsSMILValue(const nsSMILValue& aVal);
  27
  28   ~nsSMILValue()
  29   {
  30     mType->Destroy(*this);
  31   }
  32
  33   const nsSMILValue& operator=(const nsSMILValue& aVal);
  34
  35   // Equality operators. These are allowed to be conservative (return false
  36   // more than you'd expect) - see comment above nsISMILType::IsEqual.
  37   bool operator==(const nsSMILValue& aVal) const;
  38   bool operator!=(const nsSMILValue& aVal) const {
  39     return !(*this == aVal);
  40   }
  41
  42   bool IsNull() const
  43   {
  44     return (mType == nsSMILNullType::Singleton());
  45   }
  46
  47   // Swaps the member data (mU & mPtr) of |this| with |aOther|
  48   void     Swap(nsSMILValue& aOther);
  49
  50   nsresult Add(const nsSMILValue& aValueToAdd, uint32_t aCount = 1);
  51   nsresult SandwichAdd(const nsSMILValue& aValueToAdd);
  52   nsresult ComputeDistance(const nsSMILValue& aTo, double& aDistance) const;
  53   nsresult Interpolate(const nsSMILValue& aEndVal,
  54                        double aUnitDistance,
  55                        nsSMILValue& aResult) const;
  56
  57   union {
  58     bool mBool;
  59     uint64_t mUint;
  60     int64_t mInt;
  61     double mDouble;
  62     struct {
  63       float mAngle;
  64       uint16_t mUnit;
  65       uint16_t mOrientType;
  66     } mOrient;
  67     int32_t mIntPair[2];
  68     float mNumberPair[2];
  69     void* mPtr;
  70   } mU;
  71   const nsISMILType* mType;
  72
  73 protected:
  74   void InitAndCheckPostcondition(const nsISMILType* aNewType);
  75   void DestroyAndCheckPostcondition();
  76   void DestroyAndReinit(const nsISMILType* aNewType);
  77 };
  78
  79 #endif  // NS_SMILVALUE_H_