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****************************************************************************/

#ifndef QDECLARATIVEJSMEMORYPOOL_P_H

#define QDECLARATIVEJSMEMORYPOOL_P_H

//

//  W A R N I N G

//  -------------

//

// This file is not part of the Qt API.  It exists purely as an

// implementation detail.  This header file may change from version to

// version without notice, or even be removed.

//

// We mean it.

//

#include "private/qdeclarativejsglobal_p.h"

#include <QtCore/qglobal.h>

#include <QtCore/qshareddata.h>

#include <string.h>

QT_QML_BEGIN_NAMESPACE

namespace QDeclarativeJS {

class QML_PARSER_EXPORT MemoryPool : public QSharedData

{

public:

    enum { maxBlockCount = -1 };

    enum { defaultBlockSize = 1 << 12 };

    MemoryPool() {

        m_blockIndex = maxBlockCount;

        m_currentIndex = 0;

        m_storage = 0;

        m_currentBlock = 0;

        m_currentBlockSize = 0;

    }

    virtual ~MemoryPool() {

        for (int index = 0; index < m_blockIndex + 1; ++index)

            qFree(m_storage[index]);

        qFree(m_storage);

    }

    char *allocate(int bytes) {

        bytes += (8 - bytes) & 7; // ensure multiple of 8 bytes (maintain alignment)

        if (m_currentBlock == 0 || m_currentBlockSize < m_currentIndex + bytes) {

            ++m_blockIndex;

            m_currentBlockSize = defaultBlockSize << m_blockIndex;

            m_storage = reinterpret_cast<char**>(qRealloc(m_storage, sizeof(char*) * (1 + m_blockIndex)));

            m_currentBlock = m_storage[m_blockIndex] = reinterpret_cast<char*>(qMalloc(m_currentBlockSize));

            ::memset(m_currentBlock, 0, m_currentBlockSize);

            m_currentIndex = (8 - quintptr(m_currentBlock)) & 7; // ensure first chunk is 64-bit aligned

            Q_ASSERT(m_currentIndex + bytes <= m_currentBlockSize);

        }

        char *p = reinterpret_cast<char *>

            (m_currentBlock + m_currentIndex);

        m_currentIndex += bytes;

        return p;

    }

    int bytesAllocated() const {

        int bytes = 0;

        for (int index = 0; index < m_blockIndex; ++index)

            bytes += (defaultBlockSize << index);

        bytes += m_currentIndex;

        return bytes;

    }

private:

    int m_blockIndex;

    int m_currentIndex;

    char *m_currentBlock;

    int m_currentBlockSize;

    char **m_storage;

private:

    Q_DISABLE_COPY(MemoryPool)

};

} // namespace QDeclarativeJS

QT_QML_END_NAMESPACE

#endif