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      1 /*
      2  * Copyright (C) 2012 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 GridPosition_h
     32 #define GridPosition_h
     33 
     34 #include "wtf/text/WTFString.h"
     35 
     36 namespace WebCore {
     37 
     38 enum GridPositionType {
     39     AutoPosition,
     40     ExplicitPosition, // [ <integer> || <string> ]
     41     SpanPosition, // span && [ <integer> || <string> ]
     42     NamedGridAreaPosition // <ident>
     43 };
     44 
     45 enum GridPositionSide {
     46     ColumnStartSide,
     47     ColumnEndSide,
     48     RowStartSide,
     49     RowEndSide
     50 };
     51 
     52 class GridPosition {
     53 public:
     54     GridPosition()
     55         : m_type(AutoPosition)
     56         , m_integerPosition(0)
     57     {
     58     }
     59 
     60     static size_t adjustGridPositionForAfterEndSide(size_t resolvedPosition)
     61     {
     62         return resolvedPosition ? resolvedPosition - 1 : 0;
     63     }
     64 
     65     static size_t adjustGridPositionForSide(size_t resolvedPosition, GridPositionSide side)
     66     {
     67         // An item finishing on the N-th line belongs to the N-1-th cell.
     68         if (side == ColumnEndSide || side == RowEndSide)
     69             return adjustGridPositionForAfterEndSide(resolvedPosition);
     70 
     71         return resolvedPosition;
     72     }
     73 
     74     bool isPositive() const { return integerPosition() > 0; }
     75 
     76     GridPositionType type() const { return m_type; }
     77     bool isAuto() const { return m_type == AutoPosition; }
     78     bool isSpan() const { return m_type == SpanPosition; }
     79     bool isNamedGridArea() const { return m_type == NamedGridAreaPosition; }
     80 
     81     void setExplicitPosition(int position, const String& namedGridLine)
     82     {
     83         m_type = ExplicitPosition;
     84         m_integerPosition = position;
     85         m_namedGridLine = namedGridLine;
     86     }
     87 
     88     // 'span' values cannot be negative, yet we reuse the <integer> position which can
     89     // be. This means that we have to convert the span position to an integer, losing
     90     // some precision here. It shouldn't be an issue in practice though.
     91     void setSpanPosition(int position, const String& namedGridLine)
     92     {
     93         m_type = SpanPosition;
     94         m_integerPosition = position;
     95         m_namedGridLine = namedGridLine;
     96     }
     97 
     98     void setNamedGridArea(const String& namedGridArea)
     99     {
    100         m_type = NamedGridAreaPosition;
    101         m_namedGridLine = namedGridArea;
    102     }
    103 
    104     int integerPosition() const
    105     {
    106         ASSERT(type() == ExplicitPosition);
    107         return m_integerPosition;
    108     }
    109 
    110     String namedGridLine() const
    111     {
    112         ASSERT(type() == ExplicitPosition || type() == SpanPosition || type() == NamedGridAreaPosition);
    113         return m_namedGridLine;
    114     }
    115 
    116     int spanPosition() const
    117     {
    118         ASSERT(type() == SpanPosition);
    119         return m_integerPosition;
    120     }
    121 
    122     bool operator==(const GridPosition& other) const
    123     {
    124         return m_type == other.m_type && m_integerPosition == other.m_integerPosition && m_namedGridLine == other.m_namedGridLine;
    125     }
    126 
    127     bool shouldBeResolvedAgainstOppositePosition() const
    128     {
    129         return isAuto() || isSpan();
    130     }
    131 private:
    132     GridPositionType m_type;
    133     int m_integerPosition;
    134     String m_namedGridLine;
    135 };
    136 
    137 } // namespace WebCore
    138 
    139 #endif // GridPosition_h
    140