/*

 * Copyright (C) 2008, 2009 Apple Inc. All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY

 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR

 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR

 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,

 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,

 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR

 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY

 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 

 */

#include "config.h"

#include "Collector.h"

#ifndef CollectorHeapIterator_h

#define CollectorHeapIterator_h

namespace JSC {

    class CollectorHeapIterator {

    public:

        bool operator!=(const CollectorHeapIterator& other);

        JSCell* operator*() const;

    protected:

        CollectorHeapIterator(CollectorHeap&, size_t startBlock, size_t startCell);

        void advance(size_t max);

        CollectorHeap& m_heap;

        size_t m_block;

        size_t m_cell;

    };

    class LiveObjectIterator : public CollectorHeapIterator {

    public:

        LiveObjectIterator(CollectorHeap&, size_t startBlock, size_t startCell = 0);

        LiveObjectIterator& operator++();

    };

    class DeadObjectIterator : public CollectorHeapIterator {

    public:

        DeadObjectIterator(CollectorHeap&, size_t startBlock, size_t startCell = 0);

        DeadObjectIterator& operator++();

    };

    class ObjectIterator : public CollectorHeapIterator {

    public:

        ObjectIterator(CollectorHeap&, size_t startBlock, size_t startCell = 0);

        ObjectIterator& operator++();

    };

    inline CollectorHeapIterator::CollectorHeapIterator(CollectorHeap& heap, size_t startBlock, size_t startCell)

        : m_heap(heap)

        , m_block(startBlock)

        , m_cell(startCell)

    {

    }

    inline bool CollectorHeapIterator::operator!=(const CollectorHeapIterator& other)

    {

        return m_block != other.m_block || m_cell != other.m_cell;

    }

    inline JSCell* CollectorHeapIterator::operator*() const

    {

        return reinterpret_cast<JSCell*>(&m_heap.blocks[m_block]->cells[m_cell]);

    }

    // Iterators advance up to the next-to-last -- and not the last -- cell in a

    // block, since the last cell is a dummy sentinel.

    inline void CollectorHeapIterator::advance(size_t max)

    {

        ++m_cell;

        if (m_cell == max) {

            m_cell = 0;

            ++m_block;

        }

    }

    inline LiveObjectIterator::LiveObjectIterator(CollectorHeap& heap, size_t startBlock, size_t startCell)

        : CollectorHeapIterator(heap, startBlock, startCell - 1)

    {

        ++(*this);

    }

    inline LiveObjectIterator& LiveObjectIterator::operator++()

    {

        advance(HeapConstants::cellsPerBlock - 1);

        if (m_block < m_heap.nextBlock || (m_block == m_heap.nextBlock && m_cell < m_heap.nextCell))

            return *this;

        while (m_block < m_heap.usedBlocks && !m_heap.blocks[m_block]->marked.get(m_cell))

            advance(HeapConstants::cellsPerBlock - 1);

        return *this;

    }

    inline DeadObjectIterator::DeadObjectIterator(CollectorHeap& heap, size_t startBlock, size_t startCell)

        : CollectorHeapIterator(heap, startBlock, startCell - 1)

    {

        ++(*this);

    }

    inline DeadObjectIterator& DeadObjectIterator::operator++()

    {

        do {

            advance(HeapConstants::cellsPerBlock - 1);

            ASSERT(m_block > m_heap.nextBlock || (m_block == m_heap.nextBlock && m_cell >= m_heap.nextCell));

        } while (m_block < m_heap.usedBlocks && m_heap.blocks[m_block]->marked.get(m_cell));

        return *this;

    }

    inline ObjectIterator::ObjectIterator(CollectorHeap& heap, size_t startBlock, size_t startCell)

        : CollectorHeapIterator(heap, startBlock, startCell - 1)

    {

        ++(*this);

    }

    inline ObjectIterator& ObjectIterator::operator++()

    {

        advance(HeapConstants::cellsPerBlock - 1);

        return *this;

    }

} // namespace JSC

#endif // CollectorHeapIterator_h