From cd37eb3bfbabae508c9feec88f102a9e7c430916 Mon Sep 17 00:00:00 2001
From: Dave Abrahams <dave@boostpro.com>
Date: Tue, 18 Nov 2003 04:19:28 +0000
Subject: [PATCH] Modified Files:  Tag: simplify 	iterator_adaptor.hpp
 iterator_categories.hpp 	iterator_facade.hpp  Added Files:   Tag:
 simplify  	is_lvalue_iterator.hpp is_readable_iterator.hpp  
 detail/any_conversion_eater.hpp

The above files were moved over from HEAD and will cause confusion during the merge

Got iterator_adaptor_test.cpp working


[SVN r20843]
---
 include/boost/iterator/iterator_adaptor.hpp   | 106 +++++++++---------
 .../boost/iterator/iterator_categories.hpp    |  37 +++++-
 include/boost/iterator/iterator_facade.hpp    | 106 +++++++++---------
 3 files changed, 143 insertions(+), 106 deletions(-)

diff --git a/include/boost/iterator/iterator_adaptor.hpp b/include/boost/iterator/iterator_adaptor.hpp
index a47dad4..bff7062 100644
--- a/include/boost/iterator/iterator_adaptor.hpp
+++ b/include/boost/iterator/iterator_adaptor.hpp
@@ -26,6 +26,12 @@
 #include <boost/type_traits/is_same.hpp>
 #include <boost/type_traits/is_convertible.hpp>
 
+#ifdef BOOST_ITERATOR_REFERENCE_PRIMACY
+# include <boost/type_traits/remove_reference.hpp>
+#else 
+# include <boost/type_traits/add_reference.hpp>
+#endif 
+
 #include <boost/iterator/detail/config_def.hpp>
 
 #include <boost/iterator/iterator_traits.hpp>
@@ -142,55 +148,51 @@ namespace boost
         class Derived
       , class Base
       , class Value
-      , class Category
+      , class Traversal
       , class Reference
       , class Difference
     >
     struct iterator_adaptor_base
     {
-    private: // intermediate results
-
-        typedef typename mpl::apply_if<
-            mpl::or_< 
-                is_same<Category, use_default>
-              , is_access_tag<Category>
-              , is_traversal_tag<Category>
-            >
-          , BOOST_ITERATOR_CATEGORY<Base>
-          , mpl::identity<Category>
-        >::type category;
-
-        typedef typename detail::ia_dflt_help<
-            Reference
-          , mpl::apply_if<
-                is_same<Value, use_default>
-              , iterator_reference<Base>
-              , mpl::identity<Value&>
-            >
-        >::type reference;
-
-     public: // return type
         typedef iterator_facade<
             Derived
-         
+            
+# ifdef BOOST_ITERATOR_REFERENCE_PRIMACY
+          , typename detail::ia_dflt_help<
+                Value
+              , mpl::apply_if<
+                    is_same<Reference,use_default>
+                  , iterator_value<Base>
+                  , remove_reference<Reference>
+                >
+            >::type
+# else
           , typename detail::ia_dflt_help<
                 Value, iterator_value<Base>
             >::type
-                
-         , typename mpl::apply_if<
-               is_access_tag<Category>
-             , mpl::identity<Category>
-             , access_category_tag<category, reference>
-           >::type
+# endif
+            
+          , typename detail::ia_dflt_help<
+                Traversal
+              , iterator_traversal<Base>
+            >::type
+
+# ifdef BOOST_ITERATOR_REFERENCE_PRIMACY
+          , typename detail::ia_dflt_help<
+                Reference
+              , iterator_reference<Base>
+            >::type
+# else
+          , typename detail::ia_dflt_help<
+                Reference
+              , mpl::apply_if<
+                    is_same<Value,use_default>
+                  , iterator_reference<Base>
+                  , add_reference<Value>
+                >
+            >::type
+# endif 
 
-         , typename mpl::apply_if<
-               is_traversal_tag<Category>
-             , mpl::identity<Category>
-             , traversal_category_tag<category>
-           >::type
-                
-          , reference
-                
           , typename detail::ia_dflt_help<
                 Difference, iterator_difference<Base>
             >::type
@@ -213,8 +215,8 @@ namespace boost
   //      const. If const, a conforming compiler strips constness for the
   //      value_type. If not supplied, iterator_traits<Base>::value_type is used
   //
-  //   Category - the iterator_category of the resulting iterator. If not
-  //      supplied, iterator_traits<Base>::iterator_category is used.
+  //   Category - the traversal category of the resulting iterator. If not
+  //      supplied, iterator_traversal<Base>::type is used.
   //
   //   Reference - the reference type of the resulting iterator, and in
   //      particular, the result type of operator*(). If not supplied but
@@ -228,19 +230,19 @@ namespace boost
       class Derived
     , class Base
     , class Value        = use_default
-    , class Category     = use_default
+    , class Traversal    = use_default
     , class Reference    = use_default
     , class Difference   = use_default
   >
   class iterator_adaptor
     : public detail::iterator_adaptor_base<
-        Derived, Base, Value, Category, Reference, Difference
+        Derived, Base, Value, Traversal, Reference, Difference
       >::type
   {
       friend class iterator_core_access;
 
       typedef typename detail::iterator_adaptor_base<
-          Derived, Base, Value, Category, Reference, Difference
+          Derived, Base, Value, Traversal, Reference, Difference
       >::type super_t;
 
    public:
@@ -290,9 +292,9 @@ namespace boost
       {
 # if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) // seems to get instantiated incorrectly
           BOOST_STATIC_ASSERT(
-              (detail::is_tag< 
-               random_access_traversal_tag
-               , BOOST_ARG_DEPENDENT_TYPENAME super_t::iterator_category::traversal
+              (is_convertible< 
+                   BOOST_DEDUCED_TYPENAME super_t::iterator_category
+                 , random_access_traversal_tag
                >::value)
               );
 # endif 
@@ -305,9 +307,9 @@ namespace boost
       {
 # if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) // seems to get instantiated incorrectly
            BOOST_STATIC_ASSERT(
-              (detail::is_tag< 
-                   bidirectional_traversal_tag
-                 , BOOST_ARG_DEPENDENT_TYPENAME super_t::iterator_category::traversal
+              (is_convertible< 
+                   BOOST_DEDUCED_TYPENAME super_t::iterator_category
+                 , bidirectional_traversal_tag
                >::value)
               );
 # endif 
@@ -321,9 +323,9 @@ namespace boost
           iterator_adaptor<OtherDerived, OtherIterator, V, C, R, D> const& y) const
       {
           BOOST_STATIC_ASSERT(
-              (detail::is_tag< 
-                   random_access_traversal_tag
-                 , BOOST_ARG_DEPENDENT_TYPENAME super_t::iterator_category::traversal
+              (is_convertible< 
+                   BOOST_DEDUCED_TYPENAME super_t::iterator_category
+                 , random_access_traversal_tag
                >::value)
               );
           // Maybe readd with same_distance
diff --git a/include/boost/iterator/iterator_categories.hpp b/include/boost/iterator/iterator_categories.hpp
index 7388ea9..a868714 100644
--- a/include/boost/iterator/iterator_categories.hpp
+++ b/include/boost/iterator/iterator_categories.hpp
@@ -24,6 +24,15 @@
 # include <boost/type_traits/is_convertible.hpp>
 # include <boost/type_traits/is_const.hpp>
 
+# ifdef BOOST_ITERATOR_REFERENCE_PRIMACY
+#  ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
+#   include <boost/mpl/or.hpp>
+#   include <boost/python/detail/indirect_traits.hpp>
+#  else
+#   include <boost/mpl/remove_reference.hpp>
+#  endif 
+# endif
+
 namespace boost {
 
 //
@@ -48,6 +57,23 @@ namespace detail
   struct input_output_iterator_tag
     : std::input_iterator_tag, std::output_iterator_tag {};
 
+  //
+  // Helper for iterator_tag and iterator_facade.  True iff the user
+  // has explicitly disabled writability of this iterator.
+  //
+  template <class Value, class Reference>
+  struct iterator_writability_disabled
+# ifdef BOOST_ITERATOR_REFERENCE_PRIMACY
+#  ifdef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
+    : mpl::or_<is_const<Reference>,python::detail::is_reference_to_const<Reference> >
+#  else 
+    : is_const<typename remove_reference<Reference>::type>
+#  endif 
+# else 
+    : is_const<Value>
+# endif 
+  {};
+  
   template <class Value, class Reference, class Traversal>
   struct old_iterator_category
   {
@@ -80,7 +106,7 @@ namespace detail
                 , is_convertible<Reference, Value>
               >
             , mpl::if_<
-                  is_const<Value>
+                  iterator_writability_disabled<Value,Reference>
                 , std::input_iterator_tag
                 , input_output_iterator_tag
               >
@@ -122,7 +148,14 @@ namespace detail
           >
       >
   {};
-  
+
+# if BOOST_WORKAROUND(BOOST_MSVC, == 1200)
+  template <>
+  struct old_style_category_to_traversal<int>
+  {
+      typedef int type;
+  };
+# endif 
 } // namespace detail
 
 
diff --git a/include/boost/iterator/iterator_facade.hpp b/include/boost/iterator/iterator_facade.hpp
index 192a00d..c58e8cb 100644
--- a/include/boost/iterator/iterator_facade.hpp
+++ b/include/boost/iterator/iterator_facade.hpp
@@ -14,12 +14,18 @@
 #include <boost/iterator.hpp>
 #include <boost/iterator/iterator_categories.hpp>
 #include <boost/iterator/interoperable.hpp>
+#include <boost/iterator/iterator_traits.hpp>
+
 #include <boost/iterator/detail/enable_if.hpp>
 
 #include <boost/type_traits/is_same.hpp>
+#include <boost/type_traits/remove_const.hpp>
 #include <boost/type_traits/is_convertible.hpp>
 
-#include <boost/iterator/iterator_traits.hpp>
+#ifdef BOOST_ITERATOR_REFERENCE_PRIMACY
+# include <boost/type_traits/add_pointer.hpp>
+# include <boost/type_traits/add_const.hpp>
+#endif
 
 #include <boost/mpl/apply_if.hpp>
 #include <boost/mpl/or.hpp>
@@ -30,7 +36,7 @@ namespace boost
 {
   // This forward declaration is required for the friend declaration
   // in iterator_core_access
-  template <class I, class V, class AC, class TC, class R, class D> class iterator_facade;
+  template <class I, class V, class TC, class R, class D> class iterator_facade;
 
   // Used as a default template argument internally, merely to
   // indicate "use the default", this can also be passed by users
@@ -83,20 +89,15 @@ namespace boost
     //
     template <
         class Value
-      , class AccessCategory
       , class TraversalCategory
       , class Reference 
       , class Difference
     >
     struct iterator_facade_types
-    {
-        typedef iterator_tag<AccessCategory, TraversalCategory> iterator_category;
-        
-        typedef typename remove_cv<Value>::type value_type;
-        
-        typedef Difference difference_type;
-        
-        typedef typename const_qualified_ptr<Value, AccessCategory>::type pointer;
+    {        
+        typedef iterator_tag<Value, Reference, TraversalCategory> iterator_category;
+
+        typedef typename remove_const<Value>::type value_type;
         
 # if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)                          \
     && (BOOST_WORKAROUND(_STLPORT_VERSION, BOOST_TESTED_AT(0x452))              \
@@ -111,7 +112,7 @@ namespace boost
 #  define BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE 1
         
         typedef
-           iterator<iterator_category, value_type, difference_type, pointer, reference>
+           iterator<iterator_category, value_type, Difference, Value*, Reference>
         base;
 # endif 
     };
@@ -193,28 +194,24 @@ namespace boost
         Iterator m_iter;
     };
 
-    template <class Iterator, class ValueType, class Category, class Reference>
+    template <class Iterator, class Value, class Reference>
     struct operator_brackets_result
     {
-        typedef typename access_category_tag<Category,Reference>::type access_category;
-        
-        typedef is_tag<writable_iterator_tag, access_category> use_proxy;
-
-        typedef typename mpl::if_< 
-            use_proxy
+        typedef typename mpl::if_<
+            iterator_writability_disabled<Value,Reference>
+          , Value 
           , operator_brackets_proxy<Iterator>
-          , ValueType 
         >::type type;
     };
 
     template <class Iterator>
-    operator_brackets_proxy<Iterator> make_operator_brackets_result(Iterator const& iter, mpl::true_)
+    operator_brackets_proxy<Iterator> make_operator_brackets_result(Iterator const& iter, mpl::false_)
     {
         return operator_brackets_proxy<Iterator>(iter);
     }
 
     template <class Iterator>
-    typename Iterator::value_type make_operator_brackets_result(Iterator const& iter, mpl::false_)
+    typename Iterator::value_type make_operator_brackets_result(Iterator const& iter, mpl::true_)
     {
       return *iter;
     }
@@ -223,20 +220,20 @@ namespace boost
 
 
   // Macros which describe the declarations of binary operators
-#  define BOOST_ITERATOR_FACADE_INTEROP_HEAD(prefix, op, result_type)       \
-    template <                                                              \
-        class Derived1, class V1, class AC1, class TC1, class R1, class D1  \
-      , class Derived2, class V2, class AC2, class TC2, class R2, class D2  \
-    >                                                                       \
-    prefix typename detail::enable_if_interoperable<                        \
-        Derived1, Derived2, result_type                                     \
-    >::type                                                                 \
-    operator op(                                                            \
-        iterator_facade<Derived1, V1, AC1, TC1, R1, D1> const& lhs          \
-      , iterator_facade<Derived2, V2, AC2, TC2, R2, D2> const& rhs)
+#  define BOOST_ITERATOR_FACADE_INTEROP_HEAD(prefix, op, result_type)   \
+    template <                                                          \
+        class Derived1, class V1, class TC1, class R1, class D1         \
+      , class Derived2, class V2, class TC2, class R2, class D2         \
+    >                                                                   \
+    prefix typename detail::enable_if_interoperable<                    \
+        Derived1, Derived2, result_type                                 \
+    >::type                                                             \
+    operator op(                                                        \
+        iterator_facade<Derived1, V1, TC1, R1, D1> const& lhs           \
+      , iterator_facade<Derived2, V2, TC2, R2, D2> const& rhs)
 
-#  define BOOST_ITERATOR_FACADE_PLUS_HEAD(prefix,args)                      \
-    template <class Derived, class V, class AC, class TC, class R, class D> \
+#  define BOOST_ITERATOR_FACADE_PLUS_HEAD(prefix,args)              \
+    template <class Derived, class V, class TC, class R, class D>   \
     prefix Derived operator+ args
 
   //
@@ -257,7 +254,7 @@ namespace boost
    public:
 # else
       
-    template <class I, class V, class AC, class TC, class R, class D> friend class iterator_facade;
+      template <class I, class V, class TC, class R, class D> friend class iterator_facade;
 
 #  define BOOST_ITERATOR_FACADE_RELATION(op)     \
       BOOST_ITERATOR_FACADE_INTEROP_HEAD(friend,op, bool);
@@ -277,7 +274,7 @@ namespace boost
 
       BOOST_ITERATOR_FACADE_PLUS_HEAD(
           friend                                
-          , (iterator_facade<Derived, V, AC, TC, R, D> const&
+          , (iterator_facade<Derived, V, TC, R, D> const&
            , typename Derived::difference_type)
       )
       ;
@@ -285,7 +282,7 @@ namespace boost
       BOOST_ITERATOR_FACADE_PLUS_HEAD(
           friend                           
         , (typename Derived::difference_type
-           , iterator_facade<Derived, V, AC, TC, R, D> const&)
+           , iterator_facade<Derived, V, TC, R, D> const&)
       )
       ;
       
@@ -340,7 +337,6 @@ namespace boost
   template <
       class Derived             // The derived iterator type being constructed
     , class Value
-    , unsigned AccessCategory
     , class TraversalCategory
     , class Reference   = Value&
     , class Difference  = std::ptrdiff_t
@@ -348,14 +344,14 @@ namespace boost
   class iterator_facade
 # ifdef BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE
     : public detail::iterator_facade_types<
-         Value, AccessCategory, TraversalCategory, Reference, Difference
+         Value, TraversalCategory, Reference, Difference
       >::base
 #  undef BOOST_ITERATOR_FACADE_NEEDS_ITERATOR_BASE
 # endif 
   {
    private:
       //
-      // Curiously Recursive Template interface.
+      // Curiously Recurring Template interface.
       //
       typedef Derived derived_t;
       
@@ -371,11 +367,19 @@ namespace boost
 
    public:
 
-      typedef typename remove_cv<Value> value_type;
-      typedef typename Reference reference;
-      typedef typename Difference difference_type;
-      typedef typename types::pointer pointer;
-      typedef typename types::iterator_category iterator_category;
+      typedef typename remove_const<Value>::type value_type;
+      typedef Reference reference;
+      typedef Difference difference_type;
+# if BOOST_ITERATOR_REFERENCE_PRIMACY
+      typedef typename mpl::apply_if<
+          detail::iterator_writability_disabled<Value,Reference>
+        , add_pointer<typename add_const<value_type>::type>
+        , add_pointer<value_type>
+      >::type pointer;
+# else 
+      typedef Value* pointer;
+# endif 
+      typedef iterator_tag<Value,Reference,TraversalCategory> iterator_category;
 
       reference operator*() const
       {
@@ -396,12 +400,10 @@ namespace boost
           >::make(*this->derived());
       }
         
-      typename detail::operator_brackets_result<Derived,value_type,iterator_category,reference>::type
+      typename detail::operator_brackets_result<Derived,Value,Reference>::type
       operator[](difference_type n) const
       {
-          typedef typename
-              detail::operator_brackets_result<Derived,value_type,iterator_category,reference>::use_proxy
-          use_proxy;
+          typedef detail::iterator_writability_disabled<Value,Reference> use_proxy;
           
           return detail::make_operator_brackets_result<Derived>(this->derived() + n, use_proxy());
       }
@@ -581,13 +583,13 @@ namespace boost
   }
 
 BOOST_ITERATOR_FACADE_PLUS((
-  iterator_facade<Derived, V, AC, TC, R, D> const& i
+  iterator_facade<Derived, V, TC, R, D> const& i
   , typename Derived::difference_type n
 ))
 
 BOOST_ITERATOR_FACADE_PLUS((
     typename Derived::difference_type n
-    , iterator_facade<Derived, V, AC, TC, R, D> const& i
+    , iterator_facade<Derived, V, TC, R, D> const& i
 ))
 # undef BOOST_ITERATOR_FACADE_PLUS
 # undef BOOST_ITERATOR_FACADE_PLUS_HEAD