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      1 /*
      2  * Copyright (C) 2013 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 #include "config.h"
     32 #include "core/rendering/RenderLayerStackingNodeIterator.h"
     33 
     34 #include "core/rendering/RenderLayer.h"
     35 #include "core/rendering/RenderLayerStackingNode.h"
     36 
     37 namespace WebCore {
     38 
     39 RenderLayerStackingNode* RenderLayerStackingNodeIterator::next()
     40 {
     41     if (m_remainingChildren & NegativeZOrderChildren) {
     42         Vector<RenderLayerStackingNode*>* negZOrderList = m_root.negZOrderList();
     43         if (negZOrderList && m_index < negZOrderList->size())
     44             return negZOrderList->at(m_index++);
     45 
     46         m_index = 0;
     47         m_remainingChildren &= ~NegativeZOrderChildren;
     48     }
     49 
     50     if (m_remainingChildren & NormalFlowChildren) {
     51         Vector<RenderLayerStackingNode*>* normalFlowList = m_root.normalFlowList();
     52         if (normalFlowList && m_index < normalFlowList->size())
     53             return normalFlowList->at(m_index++);
     54 
     55         m_index = 0;
     56         m_remainingChildren &= ~NormalFlowChildren;
     57     }
     58 
     59     if (m_remainingChildren & PositiveZOrderChildren) {
     60         Vector<RenderLayerStackingNode*>* posZOrderList = m_root.posZOrderList();
     61         if (posZOrderList && m_index < posZOrderList->size())
     62             return posZOrderList->at(m_index++);
     63 
     64         m_index = 0;
     65         m_remainingChildren &= ~PositiveZOrderChildren;
     66     }
     67 
     68     return 0;
     69 }
     70 
     71 RenderLayerStackingNode* RenderLayerStackingNodeReverseIterator::next()
     72 {
     73     if (m_remainingChildren & NegativeZOrderChildren) {
     74         Vector<RenderLayerStackingNode*>* negZOrderList = m_root.negZOrderList();
     75         if (negZOrderList && m_index >= 0)
     76             return negZOrderList->at(m_index--);
     77 
     78         m_remainingChildren &= ~NegativeZOrderChildren;
     79         setIndexToLastItem();
     80     }
     81 
     82     if (m_remainingChildren & NormalFlowChildren) {
     83         Vector<RenderLayerStackingNode*>* normalFlowList = m_root.normalFlowList();
     84         if (normalFlowList && m_index >= 0)
     85             return normalFlowList->at(m_index--);
     86 
     87         m_remainingChildren &= ~NormalFlowChildren;
     88         setIndexToLastItem();
     89     }
     90 
     91     if (m_remainingChildren & PositiveZOrderChildren) {
     92         Vector<RenderLayerStackingNode*>* posZOrderList = m_root.posZOrderList();
     93         if (posZOrderList && m_index >= 0)
     94             return posZOrderList->at(m_index--);
     95 
     96         m_remainingChildren &= ~PositiveZOrderChildren;
     97         setIndexToLastItem();
     98     }
     99 
    100     return 0;
    101 }
    102 
    103 void RenderLayerStackingNodeReverseIterator::setIndexToLastItem()
    104 {
    105     if (m_remainingChildren & NegativeZOrderChildren) {
    106         Vector<RenderLayerStackingNode*>* negZOrderList = m_root.negZOrderList();
    107         if (negZOrderList) {
    108             m_index  = negZOrderList->size() - 1;
    109             return;
    110         }
    111 
    112         m_remainingChildren &= ~NegativeZOrderChildren;
    113     }
    114 
    115     if (m_remainingChildren & NormalFlowChildren) {
    116         Vector<RenderLayerStackingNode*>* normalFlowList = m_root.normalFlowList();
    117         if (normalFlowList) {
    118             m_index = normalFlowList->size() - 1;
    119             return;
    120         }
    121 
    122         m_remainingChildren &= ~NormalFlowChildren;
    123     }
    124 
    125     if (m_remainingChildren & PositiveZOrderChildren) {
    126         Vector<RenderLayerStackingNode*>* posZOrderList = m_root.posZOrderList();
    127         if (posZOrderList) {
    128             m_index = posZOrderList->size() - 1;
    129             return;
    130         }
    131 
    132         m_remainingChildren &= ~PositiveZOrderChildren;
    133     }
    134 
    135     // No more list to visit.
    136     ASSERT(!m_remainingChildren);
    137     m_index = -1;
    138 }
    139 
    140 } // namespace WebCore
    141