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      1 /*
      2  * Copyright (C) 2011 Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #ifndef CalculationValue_h
     32 #define CalculationValue_h
     33 
     34 #include "platform/Length.h"
     35 #include "platform/LengthFunctions.h"
     36 #include "wtf/OwnPtr.h"
     37 #include "wtf/PassOwnPtr.h"
     38 #include "wtf/RefCounted.h"
     39 #include "wtf/Vector.h"
     40 
     41 namespace WebCore {
     42 
     43 enum CalcOperator {
     44     CalcAdd = '+',
     45     CalcSubtract = '-',
     46     CalcMultiply = '*',
     47     CalcDivide = '/'
     48 };
     49 
     50 enum CalcExpressionNodeType {
     51     CalcExpressionNodeUndefined,
     52     CalcExpressionNodeNumber,
     53     CalcExpressionNodeLength,
     54     CalcExpressionNodeBinaryOperation,
     55     CalcExpressionNodeBlendLength,
     56 };
     57 
     58 class PLATFORM_EXPORT CalcExpressionNode {
     59     WTF_MAKE_FAST_ALLOCATED;
     60 public:
     61     CalcExpressionNode()
     62         : m_type(CalcExpressionNodeUndefined)
     63     {
     64     }
     65 
     66     virtual ~CalcExpressionNode()
     67     {
     68     }
     69 
     70     virtual float evaluate(float maxValue) const = 0;
     71     virtual bool operator==(const CalcExpressionNode&) const = 0;
     72 
     73     CalcExpressionNodeType type() const { return m_type; }
     74 
     75 protected:
     76     CalcExpressionNodeType m_type;
     77 };
     78 
     79 class PLATFORM_EXPORT CalculationValue : public RefCounted<CalculationValue> {
     80 public:
     81     static PassRefPtr<CalculationValue> create(PassOwnPtr<CalcExpressionNode> value, ValueRange);
     82     float evaluate(float maxValue) const;
     83 
     84     bool operator==(const CalculationValue& o) const
     85     {
     86         return *(m_value.get()) == *(o.m_value.get());
     87     }
     88 
     89     bool isNonNegative() const { return m_isNonNegative; }
     90     const CalcExpressionNode* expression() const { return m_value.get(); }
     91 
     92 private:
     93     CalculationValue(PassOwnPtr<CalcExpressionNode> value, ValueRange range)
     94         : m_value(value)
     95         , m_isNonNegative(range == ValueRangeNonNegative)
     96     {
     97     }
     98 
     99     OwnPtr<CalcExpressionNode> m_value;
    100     bool m_isNonNegative;
    101 };
    102 
    103 class PLATFORM_EXPORT CalcExpressionNumber : public CalcExpressionNode {
    104 public:
    105     explicit CalcExpressionNumber(float value)
    106         : m_value(value)
    107     {
    108         m_type = CalcExpressionNodeNumber;
    109     }
    110 
    111     bool operator==(const CalcExpressionNumber& o) const
    112     {
    113         return m_value == o.m_value;
    114     }
    115 
    116     virtual bool operator==(const CalcExpressionNode& o) const OVERRIDE
    117     {
    118         return type() == o.type() && *this == static_cast<const CalcExpressionNumber&>(o);
    119     }
    120 
    121     virtual float evaluate(float) const OVERRIDE
    122     {
    123         return m_value;
    124     }
    125 
    126     float value() const { return m_value; }
    127 
    128 private:
    129     float m_value;
    130 };
    131 
    132 inline const CalcExpressionNumber* toCalcExpressionNumber(const CalcExpressionNode* value)
    133 {
    134     ASSERT_WITH_SECURITY_IMPLICATION(!value || value->type() == CalcExpressionNodeNumber);
    135     return static_cast<const CalcExpressionNumber*>(value);
    136 }
    137 
    138 class PLATFORM_EXPORT CalcExpressionLength : public CalcExpressionNode {
    139 public:
    140     explicit CalcExpressionLength(Length length)
    141         : m_length(length)
    142     {
    143         m_type = CalcExpressionNodeLength;
    144     }
    145 
    146     bool operator==(const CalcExpressionLength& o) const
    147     {
    148         return m_length == o.m_length;
    149     }
    150 
    151     virtual bool operator==(const CalcExpressionNode& o) const OVERRIDE
    152     {
    153         return type() == o.type() && *this == static_cast<const CalcExpressionLength&>(o);
    154     }
    155 
    156     virtual float evaluate(float maxValue) const OVERRIDE
    157     {
    158         return floatValueForLength(m_length, maxValue);
    159     }
    160 
    161     const Length& length() const { return m_length; }
    162 
    163 private:
    164     Length m_length;
    165 };
    166 
    167 inline const CalcExpressionLength* toCalcExpressionLength(const CalcExpressionNode* value)
    168 {
    169     ASSERT_WITH_SECURITY_IMPLICATION(!value || value->type() == CalcExpressionNodeLength);
    170     return static_cast<const CalcExpressionLength*>(value);
    171 }
    172 
    173 class PLATFORM_EXPORT CalcExpressionBinaryOperation : public CalcExpressionNode {
    174 public:
    175     CalcExpressionBinaryOperation(PassOwnPtr<CalcExpressionNode> leftSide, PassOwnPtr<CalcExpressionNode> rightSide, CalcOperator op)
    176         : m_leftSide(leftSide)
    177         , m_rightSide(rightSide)
    178         , m_operator(op)
    179     {
    180         m_type = CalcExpressionNodeBinaryOperation;
    181     }
    182 
    183     bool operator==(const CalcExpressionBinaryOperation& o) const
    184     {
    185         return m_operator == o.m_operator && *m_leftSide == *o.m_leftSide && *m_rightSide == *o.m_rightSide;
    186     }
    187 
    188     virtual bool operator==(const CalcExpressionNode& o) const OVERRIDE
    189     {
    190         return type() == o.type() && *this == static_cast<const CalcExpressionBinaryOperation&>(o);
    191     }
    192 
    193     virtual float evaluate(float) const OVERRIDE;
    194 
    195     const CalcExpressionNode* leftSide() const { return m_leftSide.get(); }
    196     const CalcExpressionNode* rightSide() const { return m_rightSide.get(); }
    197     CalcOperator getOperator() const { return m_operator; }
    198 
    199 private:
    200     // Disallow the copy constructor. Resolves Windows link errors.
    201     CalcExpressionBinaryOperation(const CalcExpressionBinaryOperation&);
    202 
    203     OwnPtr<CalcExpressionNode> m_leftSide;
    204     OwnPtr<CalcExpressionNode> m_rightSide;
    205     CalcOperator m_operator;
    206 };
    207 
    208 inline const CalcExpressionBinaryOperation* toCalcExpressionBinaryOperation(const CalcExpressionNode* value)
    209 {
    210     ASSERT_WITH_SECURITY_IMPLICATION(!value || value->type() == CalcExpressionNodeBinaryOperation);
    211     return static_cast<const CalcExpressionBinaryOperation*>(value);
    212 }
    213 
    214 class PLATFORM_EXPORT CalcExpressionBlendLength : public CalcExpressionNode {
    215 public:
    216     CalcExpressionBlendLength(Length from, Length to, float progress)
    217         : m_from(from)
    218         , m_to(to)
    219         , m_progress(progress)
    220     {
    221         m_type = CalcExpressionNodeBlendLength;
    222     }
    223 
    224     bool operator==(const CalcExpressionBlendLength& o) const
    225     {
    226         return m_progress == o.m_progress && m_from == o.m_from && m_to == o.m_to;
    227     }
    228 
    229     virtual bool operator==(const CalcExpressionNode& o) const OVERRIDE
    230     {
    231         return type() == o.type() && *this == static_cast<const CalcExpressionBlendLength&>(o);
    232     }
    233 
    234     virtual float evaluate(float maxValue) const OVERRIDE
    235     {
    236         return (1.0f - m_progress) * floatValueForLength(m_from, maxValue) + m_progress * floatValueForLength(m_to, maxValue);
    237     }
    238 
    239     const Length& from() const { return m_from; }
    240     const Length& to() const { return m_to; }
    241     float progress() const { return m_progress; }
    242 
    243 private:
    244     Length m_from;
    245     Length m_to;
    246     float m_progress;
    247 };
    248 
    249 inline const CalcExpressionBlendLength* toCalcExpressionBlendLength(const CalcExpressionNode* value)
    250 {
    251     ASSERT_WITH_SECURITY_IMPLICATION(!value || value->type() == CalcExpressionNodeBlendLength);
    252     return static_cast<const CalcExpressionBlendLength*>(value);
    253 }
    254 
    255 } // namespace WebCore
    256 
    257 #endif // CalculationValue_h
    258