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// Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies).
// SPDX-License-Identifier: BSD-3-Clause
#ifndef QSCRIPTMEMORYPOOL_P_H
#define QSCRIPTMEMORYPOOL_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 <qglobal.h>
#include <qshareddata.h>
#include <string.h>
QT_BEGIN_NAMESPACE
namespace QScript {
class 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 QScript
QT_END_NAMESPACE
#endif
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