From 94627830e69f13b1305d4014136b8338bdc94a1f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ion=20Gazta=C3=B1aga?= <igaztanaga@gmail.com>
Date: Fri, 13 May 2016 00:19:37 +0200
Subject: [PATCH] Add reverse iterator to be used in sort algorithms

---
 .../boost/move/detail/reverse_iterator.hpp    | 171 ++++++++++++++++++
 1 file changed, 171 insertions(+)
 create mode 100644 include/boost/move/detail/reverse_iterator.hpp

diff --git a/include/boost/move/detail/reverse_iterator.hpp b/include/boost/move/detail/reverse_iterator.hpp
new file mode 100644
index 0000000..73f59ce
--- /dev/null
+++ b/include/boost/move/detail/reverse_iterator.hpp
@@ -0,0 +1,171 @@
+/////////////////////////////////////////////////////////////////////////////
+//
+// (C) Copyright Ion Gaztanaga  2014-2014
+//
+// 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)
+//
+// See http://www.boost.org/libs/move for documentation.
+//
+/////////////////////////////////////////////////////////////////////////////
+
+#ifndef BOOST_MOVE_DETAIL_REVERSE_ITERATOR_HPP
+#define BOOST_MOVE_DETAIL_REVERSE_ITERATOR_HPP
+
+#ifndef BOOST_CONFIG_HPP
+#  include <boost/config.hpp>
+#endif
+
+#if defined(BOOST_HAS_PRAGMA_ONCE)
+#  pragma once
+#endif
+
+#include <boost/move/detail/config_begin.hpp>
+#include <boost/move/detail/iterator_traits.hpp>
+#include <boost/move/detail/meta_utils.hpp>
+
+namespace boost {
+namespace movelib {
+
+template<class It>
+class reverse_iterator
+{
+   public:
+   typedef typename boost::movelib::iterator_traits<It>::pointer             pointer;
+   typedef typename boost::movelib::iterator_traits<It>::reference           reference;
+   typedef typename boost::movelib::iterator_traits<It>::difference_type     difference_type;
+   typedef typename boost::movelib::iterator_traits<It>::iterator_category   iterator_category;
+   typedef typename boost::movelib::iterator_traits<It>::value_type          value_type;
+
+
+   typedef It iterator_type;
+
+   reverse_iterator()
+      : m_current()  //Value initialization to achieve "null iterators" (N3644)
+   {}
+
+   explicit reverse_iterator(It r)
+      : m_current(r)
+   {}
+
+   reverse_iterator(const reverse_iterator& r)
+      : m_current(r.base())
+   {}
+
+   template<class OtherIt>
+   reverse_iterator( const reverse_iterator<OtherIt>& r
+                   , typename boost::move_detail::enable_if_convertible<OtherIt, It>::type* =0
+                   )
+      : m_current(r.base())
+   {}
+
+   reverse_iterator & operator=( const reverse_iterator& r)
+   {  m_current = r.base();   return *this;  }
+
+   template<class OtherIt>
+   typename boost::move_detail::enable_if_convertible<OtherIt, It, reverse_iterator &>::type
+         operator=( const reverse_iterator<OtherIt>& r)
+   {  m_current = r.base();   return *this;  }
+
+   It base() const
+   {  return m_current;  }
+
+   reference operator*() const
+   {
+      It temp(m_current);
+      --temp;
+      reference r = *temp;
+      return r;
+   }
+
+   pointer operator->() const
+   {
+      It temp(m_current);
+      --temp;
+      return iterator_arrow_result(temp);
+   }
+
+   reference operator[](difference_type off) const
+   {
+      return this->m_current[-off - 1];
+   }
+
+   reverse_iterator& operator++()
+   {
+      --m_current;
+      return *this;
+   }
+
+   reverse_iterator operator++(int)
+   {
+      reverse_iterator temp((*this));
+      --m_current;
+      return temp;
+   }
+
+   reverse_iterator& operator--()
+   {
+      ++m_current;
+      return *this;
+   }
+
+   reverse_iterator operator--(int)
+   {
+      reverse_iterator temp((*this));
+      ++m_current;
+      return temp;
+   }
+
+   friend bool operator==(const reverse_iterator& l, const reverse_iterator& r)
+   {  return l.m_current == r.m_current;  }
+
+   friend bool operator!=(const reverse_iterator& l, const reverse_iterator& r)
+   {  return l.m_current != r.m_current;  }
+
+   friend bool operator<(const reverse_iterator& l, const reverse_iterator& r)
+   {  return l.m_current > r.m_current;  }
+
+   friend bool operator<=(const reverse_iterator& l, const reverse_iterator& r)
+   {  return l.m_current >= r.m_current;  }
+
+   friend bool operator>(const reverse_iterator& l, const reverse_iterator& r)
+   {  return l.m_current < r.m_current;  }
+
+   friend bool operator>=(const reverse_iterator& l, const reverse_iterator& r)
+   {  return l.m_current <= r.m_current;  }
+
+   reverse_iterator& operator+=(difference_type off)
+   {  m_current -= off; return *this;  }
+
+   reverse_iterator& operator-=(difference_type off)
+   {  m_current += off; return *this;  }
+
+   friend reverse_iterator operator+(reverse_iterator l, difference_type off)
+   {  return (l += off);  }
+
+   friend reverse_iterator operator+(difference_type off, reverse_iterator r)
+   {  return (r += off);   }
+
+   friend reverse_iterator operator-(reverse_iterator l, difference_type off)
+   {  return (l-= off);  }
+
+   friend difference_type operator-(const reverse_iterator& l, const reverse_iterator& r)
+   {  return r.m_current - l.m_current;  }
+
+   private:
+   It m_current;   // the wrapped iterator
+};
+
+template< class Iterator >
+reverse_iterator<Iterator> make_reverse_iterator( Iterator i )
+{
+    return reverse_iterator<Iterator>(i);
+}
+
+} //namespace movelib {
+} //namespace boost {
+
+#include <boost/move/detail/config_end.hpp>
+
+#endif //BOOST_MOVE_DETAIL_REVERSE_ITERATOR_HPP