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| |
| // |
| // 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. |
| |
| #ifndef Patternist_SequenceMappingIterator_H |
| #define Patternist_SequenceMappingIterator_H |
| |
| #include <private/qabstractxmlforwarditerator_p.h> |
| #include <private/qdynamiccontext_p.h> |
| |
| QT_BEGIN_NAMESPACE |
| |
| namespace QPatternist |
| { |
| /** |
| * @short Proxies another QAbstractXmlForwardIterator, and for each item, returns the |
| * Sequence returned from a mapping function. |
| * |
| * ItemMappingIterator is practical when the items in an QAbstractXmlForwardIterator needs to |
| * be translated to another sequence, while still doing it in a pipe-lined |
| * fashion. In contrast to ItemMappingIterator, SequenceMappingIterator maps |
| * each item into another QAbstractXmlForwardIterator, and where the SequenceMappingIterator's own |
| * result is the concatenation of all those Iterators. Hence, while ItemMappingIterator |
| * is better tailored for one-to-one or one-to-zero conversion, SequenceMappingIterator |
| * is more suitable for one-to-many conversion. |
| * |
| * This is achieved by that SequenceMappingIterator's constructor takes |
| * an instance of a class, that must have the following member: |
| * |
| * @code |
| * QAbstractXmlForwardIterator<TResult>::Ptr mapToSequence(const TSource::Ptr &item, |
| * const DynamicContext::Ptr &context) const; |
| * @endcode |
| * |
| * @author Frans Englich <frans.englich@nokia.com> |
| * @see ItemMappingIterator |
| * @ingroup Patternist_iterators |
| */ |
| template<typename TResult, typename TSource, typename TMapper> |
| class SequenceMappingIterator : public QAbstractXmlForwardIterator<TResult> |
| { |
| public: |
| /** |
| * Constructs a SequenceMappingIterator. |
| * |
| * @param mapper the object that has the mapToItem() sequence. |
| * @param sourceIterator the QAbstractXmlForwardIterator whose items should be mapped. |
| * @param context the DynamicContext that will be passed to the map function. |
| * May be null. |
| */ |
| SequenceMappingIterator(const TMapper &mapper, |
| const typename QAbstractXmlForwardIterator<TSource>::Ptr &sourceIterator, |
| const DynamicContext::Ptr &context); |
| |
| virtual TResult next(); |
| virtual xsInteger count(); |
| virtual TResult current() const; |
| virtual xsInteger position() const; |
| |
| /** |
| * The reason the implementation is placed in line here, is due to a bug |
| * in MSVC-2005 version 14.00.50727.762. Note that it works with version 14.00.50727.42. |
| */ |
| virtual typename QAbstractXmlForwardIterator<TResult>::Ptr copy() const |
| { |
| return typename QAbstractXmlForwardIterator<TResult>::Ptr |
| (new SequenceMappingIterator<TResult, TSource, TMapper>(m_mapper, |
| m_mainIterator->copy(), |
| m_context)); |
| } |
| |
| private: |
| xsInteger m_position; |
| TResult m_current; |
| typename QAbstractXmlForwardIterator<TSource>::Ptr m_mainIterator; |
| typename QAbstractXmlForwardIterator<TResult>::Ptr m_currentIterator; |
| const typename DynamicContext::Ptr m_context; |
| const TMapper m_mapper; |
| }; |
| |
| template<typename TResult, typename TSource, typename TMapper> |
| SequenceMappingIterator<TResult, TSource, TMapper>::SequenceMappingIterator( |
| const TMapper &mapper, |
| const typename QAbstractXmlForwardIterator<TSource>::Ptr &iterator, |
| const DynamicContext::Ptr &context) |
| : m_position(0), |
| m_mainIterator(iterator), |
| m_context(context), |
| m_mapper(mapper) |
| { |
| Q_ASSERT(mapper); |
| Q_ASSERT(iterator); |
| } |
| |
| template<typename TResult, typename TSource, typename TMapper> |
| TResult SequenceMappingIterator<TResult, TSource, TMapper>::next() |
| { |
| /* This was once implemented with a recursive function, but the stack |
| * got blown for some inputs by that approach. */ |
| while(true) |
| { |
| while(!m_currentIterator) |
| { |
| const TSource mainItem(m_mainIterator->next()); |
| |
| if(qIsForwardIteratorEnd(mainItem)) /* We've reached the very end. */ |
| { |
| m_position = -1; |
| m_current = TResult(); |
| return TResult(); |
| } |
| else |
| m_currentIterator = m_mapper->mapToSequence(mainItem, m_context); |
| } |
| |
| m_current = m_currentIterator->next(); |
| |
| if(qIsForwardIteratorEnd(m_current)) |
| { |
| m_currentIterator.reset(); |
| continue; |
| } |
| else |
| { |
| ++m_position; |
| return m_current; |
| } |
| } |
| } |
| |
| template<typename TResult, typename TSource, typename TMapper> |
| xsInteger SequenceMappingIterator<TResult, TSource, TMapper>::count() |
| { |
| TSource unit(m_mainIterator->next()); |
| xsInteger c = 0; |
| |
| while(!qIsForwardIteratorEnd(unit)) |
| { |
| const typename QAbstractXmlForwardIterator<TResult>::Ptr sit(m_mapper->mapToSequence(unit, m_context)); |
| c += sit->count(); |
| unit = m_mainIterator->next(); |
| } |
| |
| return c; |
| } |
| |
| template<typename TResult, typename TSource, typename TMapper> |
| TResult SequenceMappingIterator<TResult, TSource, TMapper>::current() const |
| { |
| return m_current; |
| } |
| |
| template<typename TResult, typename TSource, typename TMapper> |
| xsInteger SequenceMappingIterator<TResult, TSource, TMapper>::position() const |
| { |
| return m_position; |
| } |
| |
| |
| /** |
| * @short An object generator for SequenceMappingIterator. |
| * |
| * makeSequenceMappingIterator() is a convenience function for avoiding specifying |
| * the full template instantiation for SequenceMappingIterator. Conceptually, it |
| * is identical to Qt's qMakePair(). |
| * |
| * @returns a SequenceMappingIterator wrapped in a smart pointer, that has been |
| * passed the constructor arguments @p mapper, @p source, and @p context. |
| * @see makeMappingCallbackPtr() |
| * @relates QAbstractXmlForwardIterator |
| */ |
| template<typename TResult, typename TSource, typename TMapper> |
| static inline |
| typename QAbstractXmlForwardIterator<TResult>::Ptr |
| makeSequenceMappingIterator(const TMapper &mapper, |
| const QExplicitlySharedDataPointer<QAbstractXmlForwardIterator<TSource> > &source, |
| const DynamicContext::Ptr &context) |
| { |
| return typename QAbstractXmlForwardIterator<TResult>::Ptr |
| (new SequenceMappingIterator<TResult, TSource, TMapper>(mapper, source, context)); |
| } |
| } |
| |
| QT_END_NAMESPACE |
| |
| #endif |