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/*************************************************************************
*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* Copyright 2008 by Sun Microsystems, Inc.
*
* OpenOffice.org - a multi-platform office productivity suite
*
* $RCSfile: lazy_update.hxx,v $
* $Revision: 1.3 $
*
* This file is part of OpenOffice.org.
*
* OpenOffice.org is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License version 3
* only, as published by the Free Software Foundation.
*
* OpenOffice.org is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License version 3 for more details
* (a copy is included in the LICENSE file that accompanied this code).
*
* You should have received a copy of the GNU Lesser General Public License
* version 3 along with OpenOffice.org. If not, see
* <http://www.openoffice.org/license.html>
* for a copy of the LGPLv3 License.
*
************************************************************************/
#ifndef INCLUDED_O3TL_VECTOR_POOL_HXX
#define INCLUDED_O3TL_VECTOR_POOL_HXX
#include <sal/types.h>
#include <vector>
namespace o3tl
{
namespace detail
{
template<typename ValueType, class Container> class simple_pool_impl :
public Container
{
typedef typename Container::value_type value_type;
std::ptrdiff_t mnFirstFreeIndex;
public:
simple_pool_impl() :
mnFirstFreeIndex(-1)
{}
std::ptrdiff_t alloc()
{
return store(ValueType());
}
std::ptrdiff_t store(const ValueType& rCopy)
{
if( mnFirstFreeIndex != -1 )
{
std::ptrdiff_t nIdx=mnFirstFreeIndex;
mnFirstFreeIndex = this->at(mnFirstFreeIndex).nextFree;
this->at(nIdx).value = rCopy;
this->at(nIdx).nextFree = -1;
return nIdx;
}
else
{
push_back(value_type(rCopy));
return this->size()-1;
}
}
void free( std::ptrdiff_t nIdx )
{
this->at(nIdx).nextFree = mnFirstFreeIndex;
mnFirstFreeIndex = nIdx;
}
const ValueType& get( std::ptrdiff_t nIdx ) const
{
return this->operator[](nIdx).value;
}
ValueType& get( std::ptrdiff_t nIdx )
{
return this->operator[](nIdx).value;
}
};
template< typename ValueType > struct struct_from_value
{
struct type
{
type() :
value(),
nextFree(-1)
{}
explicit type( const ValueType& val ) :
value(val),
nextFree(-1)
{}
ValueType value;
std::ptrdiff_t nextFree;
};
};
}
/** Simple vector-based memory pool allocator
This template can be used to provide simple pooled memory
allocation from a container class that adheres to the stl
random access container concept. Note that alloc/free works
with _indices_ into the container!
@example
<pre>
vector_pool<type> myPool;
int nIdx=myPool.alloc();
myPool[nIdx] = myVal;
... do stuff ...
myPool.free(nIdx);
</pre>
*/
template<typename ValueType> struct vector_pool :
public detail::simple_pool_impl<ValueType,
std::vector<typename detail::struct_from_value<ValueType>::type > >
{};
}
#endif /* INCLUDED_O3TL_VECTOR_POOL_HXX */
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