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/****************************************************************************
**
** Copyright (C) 2001-2004 Roberto Raggi
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the qt3to4 porting application of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** No Commercial Usage
** This file contains pre-release code and may not be distributed.
** You may use this file in accordance with the terms and conditions
** contained in the Technology Preview License Agreement accompanying
** this package.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights. These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
**
**
**
**
**
**
**
**
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef SMALLOBJECT_H
#define SMALLOBJECT_H
#include <QList>
#include <assert.h>
#include <stdlib.h>
#include <string.h>
QT_BEGIN_NAMESPACE
struct block_t
{
static int N;
block_t *chain;
char *data;
char *ptr;
char *end;
inline void init(int block_size = 256)
{
++N;
chain = 0;
data = (char*) malloc(block_size);
ptr = data;
end = data + block_size;
}
inline void init0(int block_size)
{
init();
memset(data, '0', block_size);
}
inline void destroy()
{
--N;
if (chain) {
chain->destroy();
free(chain);
}
free(data);
}
inline void *allocate(size_t size, block_t **right_most)
{
const unsigned int block_size = 1 << 16;
if (end < ptr + size) {
assert( size < block_size );
if (!chain) {
chain = (block_t*) malloc(sizeof(block_t));
Q_ASSERT(chain);
chain->init(block_size);
}
return chain->allocate(size, right_most);
}
char *r = ptr;
ptr += size;
if (right_most)
*right_most = this;
return r;
}
};
// a stupid memory pool
struct pool
{
block_t blk;
block_t *right_most;
inline pool() { blk.init(); right_most = &blk; }
inline ~pool() { blk.destroy(); }
inline void *allocate(size_t size)
{
void *ptr = right_most->allocate(size, &right_most);
Q_ASSERT(ptr);
return ptr;
}
inline void *reallocate(void *old, size_t old_size, size_t size)
{
void *alloc = right_most->allocate(size, &right_most);
memcpy(alloc, old, old_size);
return alloc;
}
private:
Q_DISABLE_COPY(pool)
};
/*
A memory pool that calls the destructor for each stored item when memory is
freed, at the expence storing one BaseType* per item.
Note that allocations for types that does not inherit BaseType
is not allowed and will result in a crash when the memory is freed.
*/
template <typename BaseType>
class TypedPool
{
public:
inline TypedPool() { blk.init(); right_most = &blk; }
inline ~TypedPool()
{
foreach(BaseType *item, allocated)
item->~BaseType();
blk.destroy();
}
inline void *allocate(size_t size)
{
void *memory = right_most->allocate(size, &right_most);
allocated.append(reinterpret_cast<BaseType *>(memory));
Q_ASSERT(memory);
return memory;
}
private:
Q_DISABLE_COPY(TypedPool)
block_t blk;
block_t *right_most;
QList<BaseType *> allocated;
};
struct SmallObject
{
static void *operator new(size_t size);
static void operator delete(void *p);
};
QT_END_NAMESPACE
#endif
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