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tqtinterface/qtinterface/qt4/Qt/qtconcurrentmapkernel.h

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/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the QtCore module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** 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.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file. Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you have questions regarding the use of this file, please contact
** Nokia at qt-info@nokia.com.
** $QT_END_LICENSE$
**
****************************************************************************/
#ifndef QTCONCURRENT_MAPKERNEL_H
#define QTCONCURRENT_MAPKERNEL_H
#include <QtCore/qglobal.h>
#ifndef QT_NO_CONCURRENT
#include <QtCore/qtconcurrentiteratekernel.h>
#include <QtCore/qtconcurrentreducekernel.h>
QT_BEGIN_HEADER
QT_BEGIN_NAMESPACE
QT_MODULE(Core)
#ifndef qdoc
namespace QtConcurrent {
// map kernel, works with both parallel-for and parallel-while
template <typename Iterator, typename MapFunctor>
class MapKernel : public IterateKernel<Iterator, void>
{
MapFunctor map;
public:
typedef void ReturnType;
MapKernel(Iterator begin, Iterator end, MapFunctor _map)
: IterateKernel<Iterator, void>(begin, end), map(_map)
{ }
bool runIteration(Iterator it, int, void *)
{
map(*it);
return false;
}
bool runIterations(Iterator sequenceBeginIterator, int beginIndex, int endIndex, void *)
{
Iterator it = sequenceBeginIterator;
advance(it, beginIndex);
for (int i = beginIndex; i < endIndex; ++i) {
runIteration(it, i, 0);
advance(it, 1);
}
return false;
}
};
template <typename ReducedResultType,
typename Iterator,
typename MapFunctor,
typename ReduceFunctor,
typename Reducer = ReduceKernel<ReduceFunctor,
ReducedResultType,
typename MapFunctor::result_type> >
class MappedReducedKernel : public IterateKernel<Iterator, ReducedResultType>
{
ReducedResultType reducedResult;
MapFunctor map;
ReduceFunctor reduce;
Reducer reducer;
public:
typedef ReducedResultType ReturnType;
MappedReducedKernel(Iterator begin, Iterator end, MapFunctor _map, ReduceFunctor _reduce, ReduceOptions reduceOptions)
: IterateKernel<Iterator, ReducedResultType>(begin, end), reducedResult(), map(_map), reduce(_reduce), reducer(reduceOptions)
{ }
MappedReducedKernel(ReducedResultType initialValue,
MapFunctor _map,
ReduceFunctor _reduce)
: reducedResult(initialValue), map(_map), reduce(_reduce)
{ }
bool runIteration(Iterator it, int index, ReducedResultType *)
{
IntermediateResults<typename MapFunctor::result_type> results;
results.begin = index;
results.end = index + 1;
results.vector.append(map(*it));
reducer.runReduce(reduce, reducedResult, results);
return false;
}
bool runIterations(Iterator sequenceBeginIterator, int begin, int end, ReducedResultType *)
{
IntermediateResults<typename MapFunctor::result_type> results;
results.begin = begin;
results.end = end;
results.vector.reserve(end - begin);
Iterator it = sequenceBeginIterator;
advance(it, begin);
for (int i = begin; i < end; ++i) {
results.vector.append(map(*(it)));
advance(it, 1);
}
reducer.runReduce(reduce, reducedResult, results);
return false;
}
void finish()
{
reducer.finish(reduce, reducedResult);
}
bool shouldThrottleThread()
{
return IterateKernel<Iterator, ReducedResultType>::shouldThrottleThread() || reducer.shouldThrottle();
}
bool shouldStartThread()
{
return IterateKernel<Iterator, ReducedResultType>::shouldStartThread() && reducer.shouldStartThread();
}
typedef ReducedResultType ResultType;
ReducedResultType *result()
{
return &reducedResult;
}
};
template <typename Iterator, typename MapFunctor>
class MappedEachKernel : public IterateKernel<Iterator, typename MapFunctor::result_type>
{
MapFunctor map;
typedef typename MapFunctor::result_type T;
public:
typedef T ReturnType;
typedef T ResultType;
MappedEachKernel(Iterator begin, Iterator end, MapFunctor _map)
: IterateKernel<Iterator, T>(begin, end), map(_map) { }
bool runIteration(Iterator it, int, T *result)
{
*result = map(*it);
return true;
}
bool runIterations(Iterator sequenceBeginIterator, int begin, int end, T *results)
{
Iterator it = sequenceBeginIterator;
advance(it, begin);
for (int i = begin; i < end; ++i) {
runIteration(it, i, results + (i - begin));
advance(it, 1);
}
return true;
}
};
template <typename Iterator, typename Functor>
inline ThreadEngineStarter<void> startMap(Iterator begin, Iterator end, Functor functor)
{
return startThreadEngine(new MapKernel<Iterator, Functor>(begin, end, functor));
}
template <typename T, typename Iterator, typename Functor>
inline ThreadEngineStarter<T> startMapped(Iterator begin, Iterator end, Functor functor)
{
return startThreadEngine(new MappedEachKernel<Iterator, Functor>(begin, end, functor));
}
/*
The SequnceHolder class is used to hold a reference to the
sequence we are working on.
*/
template <typename Sequence, typename Base, typename Functor>
struct SequenceHolder1 : public Base
{
SequenceHolder1(const Sequence &_sequence, Functor functor)
: Base(_sequence.begin(), _sequence.end(), functor), sequence(_sequence)
{ }
Sequence sequence;
void finish()
{
Base::finish();
// Clear the sequence to make sure all temporaries are destroyed
// before finished is signaled.
sequence = Sequence();
}
};
template <typename T, typename Sequence, typename Functor>
inline ThreadEngineStarter<T> startMapped(const Sequence &sequence, Functor functor)
{
typedef SequenceHolder1<Sequence,
MappedEachKernel<typename Sequence::const_iterator , Functor>, Functor>
SequenceHolderType;
return startThreadEngine(new SequenceHolderType(sequence, functor));
}
template <typename IntermediateType, typename ResultType, typename Sequence, typename MapFunctor, typename ReduceFunctor>
inline ThreadEngineStarter<ResultType> startMappedReduced(const Sequence & sequence,
MapFunctor mapFunctor, ReduceFunctor reduceFunctor,
ReduceOptions options)
{
typedef typename Sequence::const_iterator Iterator;
typedef ReduceKernel<ReduceFunctor, ResultType, IntermediateType> Reducer;
typedef MappedReducedKernel<ResultType, Iterator, MapFunctor, ReduceFunctor, Reducer> MappedReduceType;
typedef SequenceHolder2<Sequence, MappedReduceType, MapFunctor, ReduceFunctor> SequenceHolderType;
return startThreadEngine(new SequenceHolderType(sequence, mapFunctor, reduceFunctor, options));
}
template <typename IntermediateType, typename ResultType, typename Iterator, typename MapFunctor, typename ReduceFunctor>
inline ThreadEngineStarter<ResultType> startMappedReduced(Iterator begin, Iterator end,
MapFunctor mapFunctor, ReduceFunctor reduceFunctor,
ReduceOptions options)
{
typedef ReduceKernel<ReduceFunctor, ResultType, IntermediateType> Reducer;
typedef MappedReducedKernel<ResultType, Iterator, MapFunctor, ReduceFunctor, Reducer> MappedReduceType;
return startThreadEngine(new MappedReduceType(begin, end, mapFunctor, reduceFunctor, options));
}
} // namespace QtConcurrent
#endif //qdoc
QT_END_NAMESPACE
QT_END_HEADER
#endif // QT_NO_CONCURRENT
#endif