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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
// Qt-Security score:significant
#ifndef QQMLJSMEMORYPOOL_P_H
#define QQMLJSMEMORYPOOL_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 <QtCore/private/qglobal_p.h>
#include <QtCore/qstring.h>
#include <QtCore/qvector.h>
#include <cstdlib>
QT_BEGIN_NAMESPACE
namespace QQmlJS {
class Managed;
class MemoryPool
{
Q_DISABLE_COPY_MOVE(MemoryPool);
public:
MemoryPool() = default;
~MemoryPool()
{
if (_blocks) {
for (int i = 0; i < _allocatedBlocks; ++i) {
if (char *b = _blocks[i])
free(b);
}
free(_blocks);
}
}
inline void *allocate(size_t size)
{
size = (size + 7) & ~size_t(7);
if (Q_LIKELY(_ptr && size < size_t(_end - _ptr))) {
void *addr = _ptr;
_ptr += size;
return addr;
}
return allocate_helper(size);
}
void reset()
{
_blockCount = -1;
_ptr = _end = nullptr;
}
template <typename Tp> Tp *New() { return new (this->allocate(sizeof(Tp))) Tp(); }
template <typename Tp, typename... Ta> Tp *New(Ta... args)
{ return new (this->allocate(sizeof(Tp))) Tp(args...); }
QStringView newString(QString string) {
return strings.emplace_back(std::move(string));
}
private:
Q_NEVER_INLINE void *allocate_helper(size_t size)
{
size_t currentBlockSize = DEFAULT_BLOCK_SIZE;
while (Q_UNLIKELY(size >= currentBlockSize))
currentBlockSize *= 2;
if (++_blockCount == _allocatedBlocks) {
if (! _allocatedBlocks)
_allocatedBlocks = DEFAULT_BLOCK_COUNT;
else
_allocatedBlocks *= 2;
_blocks = reinterpret_cast<char **>(realloc(_blocks, sizeof(char *) * size_t(_allocatedBlocks)));
Q_CHECK_PTR(_blocks);
for (int index = _blockCount; index < _allocatedBlocks; ++index)
_blocks[index] = nullptr;
}
char *&block = _blocks[_blockCount];
if (! block) {
block = reinterpret_cast<char *>(malloc(currentBlockSize));
Q_CHECK_PTR(block);
}
_ptr = block;
_end = _ptr + currentBlockSize;
void *addr = _ptr;
_ptr += size;
return addr;
}
private:
char **_blocks = nullptr;
int _allocatedBlocks = 0;
int _blockCount = -1;
char *_ptr = nullptr;
char *_end = nullptr;
QStringList strings;
enum
{
DEFAULT_BLOCK_SIZE = 8 * 1024,
DEFAULT_BLOCK_COUNT = 8
};
};
class Managed
{
Q_DISABLE_COPY(Managed)
public:
Managed() = default;
~Managed() = default;
void *operator new(size_t size, MemoryPool *pool) { return pool->allocate(size); }
void operator delete(void *) {}
void operator delete(void *, MemoryPool *) {}
};
} // namespace QQmlJS
QT_END_NAMESPACE
#endif