runtime/CollectorHeapIterator.h

   1 /*
   2  * Copyright (C) 2008, 2009 Apple 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
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
  14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
  17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
  18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
  20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
  21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "config.h"
  27 #include "Collector.h"
  28
  29 #ifndef CollectorHeapIterator_h
  30 #define CollectorHeapIterator_h
  31
  32 namespace JSC {
  33
  34     template <HeapType heapType> class CollectorHeapIterator {
  35     public:
  36         CollectorHeapIterator(CollectorBlock** block, CollectorBlock** endBlock);
  37
  38         bool operator!=(const CollectorHeapIterator<heapType>& other) { return m_block != other.m_block || m_cell != other.m_cell; }
  39         CollectorHeapIterator<heapType>& operator++();
  40         JSCell* operator*() const;
  41
  42     private:
  43         typedef typename HeapConstants<heapType>::Block Block;
  44         typedef typename HeapConstants<heapType>::Cell Cell;
  45
  46         Block** m_block;
  47         Block** m_endBlock;
  48         Cell* m_cell;
  49         Cell* m_endCell;
  50     };
  51
  52     template <HeapType heapType>
  53     CollectorHeapIterator<heapType>::CollectorHeapIterator(CollectorBlock** block, CollectorBlock** endBlock)
  54         : m_block(reinterpret_cast<Block**>(block))
  55         , m_endBlock(reinterpret_cast<Block**>(endBlock))
  56         , m_cell(m_block == m_endBlock ? 0 : (*m_block)->cells)
  57         , m_endCell(m_block == m_endBlock ? 0 : (*m_block)->cells + HeapConstants<heapType>::cellsPerBlock)
  58     {
  59         if (m_cell && m_cell->u.freeCell.zeroIfFree == 0)
  60             ++*this;
  61     }
  62
  63     template <HeapType heapType>
  64     CollectorHeapIterator<heapType>& CollectorHeapIterator<heapType>::operator++()
  65     {
  66         do {
  67             for (++m_cell; m_cell != m_endCell; ++m_cell)
  68                 if (m_cell->u.freeCell.zeroIfFree != 0) {
  69                     return *this;
  70                 }
  71
  72             if (++m_block != m_endBlock) {
  73                 m_cell = (*m_block)->cells;
  74                 m_endCell = (*m_block)->cells + HeapConstants<heapType>::cellsPerBlock;
  75             }
  76         } while(m_block != m_endBlock);
  77
  78         m_cell = 0;
  79         return *this;
  80     }
  81
  82     template <HeapType heapType>
  83     JSCell* CollectorHeapIterator<heapType>::operator*() const
  84     {
  85         return reinterpret_cast<JSCell*>(m_cell);
  86     }
  87
  88 } // namespace JSC
  89
  90 #endif // CollectorHeapIterator_h