forked from boostorg/iterator
73e6736566
also simplified the implementation by using the index iterator as the base instead of the element iterator [SVN r21765]
71 lines
2.3 KiB
C++
71 lines
2.3 KiB
C++
// (C) Copyright Toon Knapen 2001.
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// (C) Copyright David Abrahams 2003.
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// (C) Copyright Roland Richter 2003.
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// Permission to copy, use, modify, sell and distribute this software
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// is granted provided this copyright notice appears in all copies.
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// This software is provided "as is" without express or implied
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// warranty, and with no claim as to its suitability for any purpose.
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#ifndef BOOST_PERMUTATION_ITERATOR_HPP
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#define BOOST_PERMUTATION_ITERATOR_HPP
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#include <iterator>
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#include <boost/iterator/iterator_adaptor.hpp>
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namespace boost
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{
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template< class ElementIterator
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, class IndexIterator
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, class ValueT = use_default
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, class CategoryT = use_default
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, class ReferenceT = use_default
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, class DifferenceT = use_default >
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class permutation_iterator
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: public iterator_adaptor<
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permutation_iterator<ElementIterator, IndexIterator, ValueT, CategoryT, ReferenceT, DifferenceT>
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, IndexIterator, ValueT, CategoryT, ReferenceT, DifferenceT >
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{
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typedef iterator_adaptor<
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permutation_iterator<ElementIterator, IndexIterator, ValueT, CategoryT, ReferenceT, DifferenceT>
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, IndexIterator, ValueT, CategoryT, ReferenceT, DifferenceT > super_t;
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friend class iterator_core_access;
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public:
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permutation_iterator() : m_elt_iter() {}
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explicit permutation_iterator(ElementIterator x, IndexIterator y)
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: super_t(y), m_elt_iter(x) {}
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template<class OtherElementIterator, class OtherIndexIterator, class V, class C, class R, class D >
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permutation_iterator(
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permutation_iterator<OtherElementIterator, OtherIndexIterator, V, C, R, D> const& r
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, typename enable_if_convertible<OtherElementIterator, ElementIterator>::type* = 0
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, typename enable_if_convertible<OtherIndexIterator, IndexIterator>::type* = 0
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)
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: super_t(r.base()), m_elt_iter(r.m_elt_iter)
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{}
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private:
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typename super_t::reference dereference() const
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{ return *(m_elt_iter + *this->base()); }
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ElementIterator m_elt_iter;
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};
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template <class ElementIterator, class IndexIterator>
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permutation_iterator<ElementIterator, IndexIterator>
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make_permutation_iterator( ElementIterator e, IndexIterator i )
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{
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return permutation_iterator<ElementIterator, IndexIterator>( e, i );
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}
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} // namespace boost
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#endif
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