From 2183de96a148ff692812fefcea32f5ce447bf198 Mon Sep 17 00:00:00 2001
From: Thomas Witt <witt@acm.org>
Date: Tue, 6 Jan 2004 19:44:06 +0000
Subject: [PATCH] Reverted unwanted checkin.

[SVN r21520]
---
 include/boost/iterator/iterator_facade.hpp | 144 +++------------------
 1 file changed, 18 insertions(+), 126 deletions(-)

diff --git a/include/boost/iterator/iterator_facade.hpp b/include/boost/iterator/iterator_facade.hpp
index bdc7eb3..79b2d3c 100644
--- a/include/boost/iterator/iterator_facade.hpp
+++ b/include/boost/iterator/iterator_facade.hpp
@@ -63,72 +63,6 @@ namespace boost
 #endif
     };
 
-    //
-    // Determines the iterator type that can be
-    // safely used to implement binary operators
-    //
-    template <
-        class Facade1,
-       class Facade2
-    >
-    struct interoperable_base 
-      : mpl::if_<
-            is_convertible<Facade1, Facade2>
-          , Facade2
-          , Facade1
-        >
-    {
-    };
-
-    template <class Facade1, class Facade2>
-    struct difference_type
-    {
-      typedef typename interoperable_base<Facade1, Facade2>::type::difference_type type;
-    };
-
-    template <class Facade1, class Facade2>
-    bool equal(Facade1 const&, Facade2 const&);
-
-    template <class Facade1, class Facade2>
-    typename Facade1::difference_type distance_to(Facade1 const&, Facade2 const&);
-
-    template <bool UseLhsMember>
-    struct facade_binary_operator
-    {
-      template <class Facade1, class Facade2>
-      static bool equal(Facade1 const& lhs,
-                        Facade2 const& rhs)
-      {
-        return ::boost::detail::equal(lhs, rhs);
-      }
-
-      template <class Facade1, class Facade2>
-      static typename Facade1::difference_type distance_to(Facade1 const& lhs,
-                                                         Facade2 const& rhs)
-      {
-        return ::boost::detail::distance_to(lhs, rhs);
-      }
-    };
-    
-    template <>
-    struct facade_binary_operator<false>
-    {
-      template <class Facade1, class Facade2>
-      static bool equal(Facade1 const& lhs,
-                        Facade2 const& rhs)
-      {
-        return ::boost::detail::equal(rhs, lhs);
-      }
-
-      template <class Facade1, class Facade2>
-      static typename Facade2::difference_type distance_to(Facade1 const& lhs,
-                                                         Facade2 const& rhs)
-      {
-        return -::boost::detail::distance_to(rhs, lhs);
-      }
-    };
-    
-
     //
     // Generates associated types for an iterator_facade with the
     // given parameters.
@@ -322,11 +256,9 @@ namespace boost
       BOOST_ITERATOR_FACADE_RELATION(>=)
 #  undef BOOST_ITERATOR_FACADE_RELATION
 
-      template < class Derived1, class V1, class TC1, class R1, class D1 , class Derived2, class V2, class TC2, class R2, class D2 > friend typename detail::enable_if_interoperable< Derived1, Derived2, typename std::iterator_traits<typename detail::interoperable_base<Derived1, Derived2> ::type > ::difference_type > ::type operator -( iterator_facade<Derived1, V1, TC1, R1, D1> const& lhs , iterator_facade<Derived2, V2, TC2, R2, D2> const& rhs);
-
-//       BOOST_ITERATOR_FACADE_INTEROP_HEAD(
-//                                          friend, -, (typename std::iterator_traits<typename detail::interoperable_base<Derived1, Derived2>::type >::difference_type))
-//       ;
+      BOOST_ITERATOR_FACADE_INTEROP_HEAD(
+          friend, -, typename Derived1::difference_type)
+      ;
 
       BOOST_ITERATOR_FACADE_PLUS_HEAD(
           friend                                
@@ -365,7 +297,7 @@ namespace boost
       template <class Facade1, class Facade2>
       static bool equal(Facade1 const& f1, Facade2 const& f2)
       {
-        return detail::facade_binary_operator< is_convertible< Facade2, Facade1 >::value >::equal(f1, f2);
+          return f1.equal(f2);
       }
 
       template <class Facade>
@@ -375,51 +307,17 @@ namespace boost
       }
 
       template <class Facade1, class Facade2>
-      static typename detail::difference_type<Facade1, Facade2>::type distance_to(
-                                                           Facade1 const& f1, Facade2 const& f2)
-      {
-        return detail::facade_binary_operator< is_convertible< Facade2, Facade1 >::value >::distance_to(f1, f2);
-      }
-
-   private:
-      // objects of this class are useless
-      iterator_core_access(); //undefined
-
-    // We would need template friends for these to be private
-   public:
-      template <class Facade1, class Facade2>
-      static bool equal_fwd(Facade1 const& f1, Facade2 const& f2)
-      {
-          return f1.equal(f2);
-      }
-
-      template <class Facade1, class Facade2>
-      static typename Facade1::difference_type distance_to_fwd(
+      static typename Facade1::difference_type distance_to(
                                                            Facade1 const& f1, Facade2 const& f2)
       {
           return f1.distance_to(f2);
       }
 
+   private:
+      // objects of this class are useless
+      iterator_core_access(); //undefined
   };
 
-  namespace detail
-  {
-
-
-    template <class Facade1, class Facade2>
-    bool equal(Facade1 const& f1, Facade2 const& f2)
-    {
-      return iterator_core_access::equal_fwd(f1, f2);
-    }
-
-    template <class Facade1, class Facade2>
-    typename Facade1::difference_type distance_to(Facade1 const& f1, Facade2 const& f2)
-    {
-      return iterator_core_access::distance_to_fwd(f1, f2);
-    }
-
-  }
-
   //
   // iterator_facade - use as a public base class for defining new
   // standard-conforming iterators.
@@ -652,25 +550,19 @@ namespace boost
   BOOST_ITERATOR_FACADE_RELATION(>=, return 0 <=, distance_to)
 # undef BOOST_ITERATOR_FACADE_RELATION
 
-//   // operator- requires an additional part in the static assertion
-//   BOOST_ITERATOR_FACADE_INTEROP(
-//       -
-//     , typename Derived1::difference_type
-//     , (is_same<
-//            BOOST_DEDUCED_TYPENAME Derived1::difference_type
-//          , BOOST_DEDUCED_TYPENAME Derived2::difference_type
-//        >::value)
-//     , return
-  //    , distance_to )
+  // operator- requires an additional part in the static assertion
+  BOOST_ITERATOR_FACADE_INTEROP(
+      -
+    , typename Derived1::difference_type
+    , (is_same<
+           BOOST_DEDUCED_TYPENAME Derived1::difference_type
+         , BOOST_DEDUCED_TYPENAME Derived2::difference_type
+       >::value)
+    , return
+    , distance_to )
 # undef BOOST_ITERATOR_FACADE_INTEROP
 # undef BOOST_ITERATOR_FACADE_INTEROP_HEAD
 
-    template < class Derived1, class V1, class TC1, class R1, class D1 , class Derived2, class V2, class TC2, class R2, class D2 > typename detail::enable_if_interoperable< Derived1, Derived2, typename std::iterator_traits<typename detail::interoperable_base<Derived1, Derived2> ::type > ::difference_type > ::type operator -( iterator_facade<Derived1, V1, TC1, R1, D1> const& lhs , iterator_facade<Derived2, V2, TC2, R2, D2> const& rhs)
-  {
-    return iterator_core_access::distance_to(static_cast<Derived2 const&>(rhs), static_cast<Derived1 const&>(lhs));
-  }
-
-
 # define BOOST_ITERATOR_FACADE_PLUS(args)           \
   BOOST_ITERATOR_FACADE_PLUS_HEAD(inline, args)     \
   {                                                 \