整理

include/boost/iterator/permutation_iterator.hpp

@@ -0,0 +1,85 @@
+// (C) Copyright Toon Knapen    2001.
+// (C) Copyright David Abrahams 2003.
+// (C) Copyright Roland Richter 2003.
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
+
+#ifndef BOOST_ITERATOR_PERMUTATION_ITERATOR_HPP_INCLUDED_
+#define BOOST_ITERATOR_PERMUTATION_ITERATOR_HPP_INCLUDED_
+
+#include <iterator>
+
+#include <boost/core/use_default.hpp>
+#include <boost/iterator/iterator_adaptor.hpp>
+#include <boost/iterator/enable_if_convertible.hpp>
+
+namespace boost {
+namespace iterators {
+
+template< typename ElementIterator, typename IndexIterator >
+class permutation_iterator :
+    public iterator_adaptor<
+        permutation_iterator< ElementIterator, IndexIterator >,
+        IndexIterator,
+        typename std::iterator_traits< ElementIterator >::value_type,
+        use_default,
+        typename std::iterator_traits< ElementIterator >::reference
+    >
+{
+    friend class iterator_core_access;
+    template< typename, typename >
+    friend class permutation_iterator;
+
+private:
+    using super_t = iterator_adaptor<
+        permutation_iterator< ElementIterator, IndexIterator >,
+        IndexIterator,
+        typename std::iterator_traits< ElementIterator >::value_type,
+        use_default,
+        typename std::iterator_traits< ElementIterator >::reference
+    >;
+
+public:
+    permutation_iterator() :
+        m_elt_iter()
+    {}
+
+    explicit permutation_iterator(ElementIterator x, IndexIterator y) :
+        super_t(y),
+        m_elt_iter(x)
+    {}
+
+    template<
+        typename OtherElementIterator,
+        typename OtherIndexIterator,
+        typename = enable_if_convertible_t< OtherElementIterator, ElementIterator >,
+        typename = enable_if_convertible_t< OtherIndexIterator, IndexIterator >
+    >
+    permutation_iterator(permutation_iterator< OtherElementIterator, OtherIndexIterator > const& r) :
+        super_t(r.base()),
+        m_elt_iter(r.m_elt_iter)
+    {}
+
+private:
+    typename super_t::reference dereference() const { return *(m_elt_iter + *this->base()); }
+
+private:
+    ElementIterator m_elt_iter;
+};
+
+
+template< typename ElementIterator, typename IndexIterator >
+inline permutation_iterator< ElementIterator, IndexIterator > make_permutation_iterator(ElementIterator e, IndexIterator i)
+{
+    return permutation_iterator< ElementIterator, IndexIterator >(e, i);
+}
+
+} // namespace iterators
+
+using iterators::permutation_iterator;
+using iterators::make_permutation_iterator;
+
+} // namespace boost
+
+#endif // BOOST_ITERATOR_PERMUTATION_ITERATOR_HPP_INCLUDED_