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#ifndef QTCONCURRENT_MAPKERNEL_H
#define QTCONCURRENT_MAPKERNEL_H
#include <QtConcurrent/qtconcurrent_global.h>
#ifndef QT_NO_CONCURRENT
#include <QtConcurrent/qtconcurrentiteratekernel.h>
#include <QtConcurrent/qtconcurrentreducekernel.h>
QT_BEGIN_NAMESPACE
#ifndef Q_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 *) override
{
map(*it);
return false;
}
bool runIterations(Iterator sequenceBeginIterator, int beginIndex, int endIndex, void *) override
{
Iterator it = sequenceBeginIterator;
std::advance(it, beginIndex);
for (int i = beginIndex; i < endIndex; ++i) {
runIteration(it, i, 0);
std::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 *) override
{
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 *) override
{
IntermediateResults<typename MapFunctor::result_type> results;
results.begin = begin;
results.end = end;
results.vector.reserve(end - begin);
Iterator it = sequenceBeginIterator;
std::advance(it, begin);
for (int i = begin; i < end; ++i) {
results.vector.append(map(*(it)));
std::advance(it, 1);
}
reducer.runReduce(reduce, reducedResult, results);
return false;
}
void finish() override
{
reducer.finish(reduce, reducedResult);
}
bool shouldThrottleThread() override
{
return IterateKernel<Iterator, ReducedResultType>::shouldThrottleThread() || reducer.shouldThrottle();
}
bool shouldStartThread() override
{
return IterateKernel<Iterator, ReducedResultType>::shouldStartThread() && reducer.shouldStartThread();
}
typedef ReducedResultType ResultType;
ReducedResultType *result() override
{
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) override
{
*result = map(*it);
return true;
}
bool runIterations(Iterator sequenceBeginIterator, int begin, int end, T *results) override
{
Iterator it = sequenceBeginIterator;
std::advance(it, begin);
for (int i = begin; i < end; ++i) {
runIteration(it, i, results + (i - begin));
std::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() override
{
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 //Q_QDOC
QT_END_NAMESPACE
#endif // QT_NO_CONCURRENT
#endif