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    41 

    42 #ifndef QDECLARATIVEJSMEMORYPOOL_P_H

    43 #define QDECLARATIVEJSMEMORYPOOL_P_H

    44 

    45 //

    46 //  W A R N I N G

    47 //  -------------

    48 //

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

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

    51 // version without notice, or even be removed.

    52 //

    53 // We mean it.

    54 //

    55 

    56 #include "private/qdeclarativejsglobal_p.h"

    57 

    58 #include <QtCore/qglobal.h>

    59 #include <QtCore/qshareddata.h>

    60 

    61 #include <string.h>

    62 

    63 QT_QML_BEGIN_NAMESPACE

    64 

    65 namespace QDeclarativeJS {

    66 

    67 class QML_PARSER_EXPORT MemoryPool : public QSharedData

    68 {

    69 public:

    70     enum { maxBlockCount = -1 };

    71     enum { defaultBlockSize = 1 << 12 };

    72 

    73     MemoryPool() {

    74         m_blockIndex = maxBlockCount;

    75         m_currentIndex = 0;

    76         m_storage = 0;

    77         m_currentBlock = 0;

    78         m_currentBlockSize = 0;

    79     }

    80 

    81     virtual ~MemoryPool() {

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

    83             qFree(m_storage[index]);

    84 

    85         qFree(m_storage);

    86     }

    87 

    88     char *allocate(int bytes) {

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

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

    91             ++m_blockIndex;

    92             m_currentBlockSize = defaultBlockSize << m_blockIndex;

    93 

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

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

    96             ::memset(m_currentBlock, 0, m_currentBlockSize);

    97 

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

    99             Q_ASSERT(m_currentIndex + bytes <= m_currentBlockSize);

   100         }

   101 

   102         char *p = reinterpret_cast<char *>

   103             (m_currentBlock + m_currentIndex);

   104 

   105         m_currentIndex += bytes;

   106 

   107         return p;

   108     }

   109 

   110     int bytesAllocated() const {

   111         int bytes = 0;

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

   113             bytes += (defaultBlockSize << index);

   114         bytes += m_currentIndex;

   115         return bytes;

   116     }

   117 

   118 private:

   119     int m_blockIndex;

   120     int m_currentIndex;

   121     char *m_currentBlock;

   122     int m_currentBlockSize;

   123     char **m_storage;

   124 

   125 private:

   126     Q_DISABLE_COPY(MemoryPool)

   127 };

   128 

   129 } // namespace QDeclarativeJS

   130 

   131 QT_QML_END_NAMESPACE

   132 

   133 #endif