From 5fd440c1d0ace58431bcc74e168f7c2522e3a3b8 Mon Sep 17 00:00:00 2001
From: Jeremy Siek <jeremy.siek@gmail.com>
Date: Thu, 24 Oct 2002 18:56:16 +0000
Subject: [PATCH] change to new/old category recognition code

[SVN r613]
---
 .../boost/iterator/iterator_categories.hpp    | 70 ++++++++++++++++++-
 include/boost/iterator/iterator_concepts.hpp  | 21 ++----
 test/concept_tests.cpp                        | 17 +++--
 3 files changed, 84 insertions(+), 24 deletions(-)

diff --git a/include/boost/iterator/iterator_categories.hpp b/include/boost/iterator/iterator_categories.hpp
index ae2217d..62b1c31 100644
--- a/include/boost/iterator/iterator_categories.hpp
+++ b/include/boost/iterator/iterator_categories.hpp
@@ -12,7 +12,8 @@
 #include <boost/type_traits/cv_traits.hpp>
 #include <boost/pending/ct_if.hpp>
 #include <boost/detail/iterator.hpp>
-#include <boost/mpl/if.hpp>
+#include <boost/mpl/apply_if.hpp>
+#include <boost/type_traits/ice.hpp>
 #include <iterator>
 
 namespace boost {
@@ -119,6 +120,7 @@ namespace boost {
         >::type type;
     };
 
+#if 0
     struct return_category_from_old_traits {
       template <typename Iterator> class bind {
         typedef boost::detail::iterator_traits<Iterator> OldTraits;
@@ -157,9 +159,25 @@ namespace boost {
     public:
       typedef typename Choice:: template bind<Iterator>::type type;
     };
+#else
+
+
+    template <class T>
+    type_traits::yes_type is_new_iter_cat(T*, typename T::traversal* = 0) { }
+
+    type_traits::no_type is_new_iter_cat(...) { }
+
+    template <class Tag>
+    struct is_new_iterator_tag
+    {
+      static Tag* t;
+      enum { value = sizeof(is_new_iter_cat(t)) == sizeof(type_traits::yes_type) };
+    };
+#endif
     
   } // namespace detail
   
+#if 0
   template <class Iterator>
   struct return_category {
     typedef typename detail::choose_return_category<Iterator>::type type;
@@ -170,6 +188,56 @@ namespace boost {
   struct traversal_category {
     typedef typename detail::choose_traversal_category<Iterator>::type type;
   };
+#else
+
+  namespace detail {
+
+    template <class NewCategoryTag>
+    struct get_return_category {
+      typedef typename NewCategoryTag::returns type;
+    };
+    template <class NewCategoryTag>
+    struct get_traversal_category {
+      typedef typename NewCategoryTag::traversal type;
+    };
+
+    template <class CategoryTag, class Value>
+    struct return_category_tag
+    {
+      typedef typename 
+	mpl::apply_if< 
+	  is_new_iterator_tag<CategoryTag>
+	  , get_return_category<CategoryTag>
+	  , iter_category_to_return<CategoryTag, Value>
+	>::type type;
+    };
+    template <class CategoryTag, class Value>
+    struct traversal_category_tag
+    {
+      typedef typename 
+	mpl::apply_if< 
+	  is_new_iterator_tag<CategoryTag>
+	  , get_traversal_category<CategoryTag>
+	  , iter_category_to_return<CategoryTag, Value>
+	>::type type;
+    };
+
+  } // namespace detail
+
+  template <class Iterator>
+  struct return_category {
+    typedef typename detail::return_category_tag<
+      typename detail::iterator_traits<Iterator>::iterator_category
+      , typename detail::iterator_traits<Iterator>::value_type>::type type;
+  };
+
+  template <class Iterator>
+  struct traversal_category {
+    typedef typename detail::traversal_category_tag<
+      typename detail::iterator_traits<Iterator>::iterator_category
+      , typename detail::iterator_traits<Iterator>::value_type>::type type;
+  };
+#endif
 
 #if !defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)
 
diff --git a/include/boost/iterator/iterator_concepts.hpp b/include/boost/iterator/iterator_concepts.hpp
index 349244d..743b111 100644
--- a/include/boost/iterator/iterator_concepts.hpp
+++ b/include/boost/iterator/iterator_concepts.hpp
@@ -26,8 +26,7 @@ namespace boost_concepts {
   public:
     typedef typename std::iterator_traits<Iterator>::value_type value_type;
     typedef typename std::iterator_traits<Iterator>::reference reference;
-    typedef typename std::iterator_traits<Iterator>::iterator_category iterator_category;
-    typedef typename iterator_category::returns return_category;
+    typedef typename boost::return_category<Iterator>::type return_category;
 
     void constraints() {
       boost::function_requires< boost::SGIAssignableConcept<Iterator> >();
@@ -48,8 +47,7 @@ namespace boost_concepts {
   template <typename Iterator, typename ValueType>
   class WritableIteratorConcept {
   public:
-    typedef typename std::iterator_traits<Iterator>::iterator_category iterator_category;
-    typedef typename iterator_category::returns return_category;
+    typedef typename boost::return_category<Iterator>::type return_category;
 
     void constraints() {
       boost::function_requires< boost::SGIAssignableConcept<Iterator> >();
@@ -71,8 +69,7 @@ namespace boost_concepts {
   public:
     typedef typename std::iterator_traits<Iterator>::value_type value_type;
     typedef typename std::iterator_traits<Iterator>::reference reference;
-    typedef typename std::iterator_traits<Iterator>::iterator_category iterator_category;
-    typedef typename iterator_category::returns return_category;
+    typedef typename boost::return_category<Iterator>::type return_category;
 
     void constraints() {
       boost::function_requires< ReadableIteratorConcept<Iterator> >();
@@ -94,8 +91,7 @@ namespace boost_concepts {
   public:
     typedef typename std::iterator_traits<Iterator>::value_type value_type;
     typedef typename std::iterator_traits<Iterator>::reference reference;
-    typedef typename std::iterator_traits<Iterator>::iterator_category iterator_category;
-    typedef typename iterator_category::returns return_category;
+    typedef typename boost::return_category<Iterator>::type return_category;
 
     void constraints() {
       boost::function_requires< ReadableIteratorConcept<Iterator> >();
@@ -119,8 +115,7 @@ namespace boost_concepts {
   template <typename Iterator>
   class ForwardTraversalConcept {
   public:
-    typedef typename std::iterator_traits<Iterator>::iterator_category iterator_category;
-    typedef typename iterator_category::traversal traversal_category;
+    typedef typename boost::traversal_category<Iterator>::type traversal_category;
 
     void constraints() {
       boost::function_requires< boost::SGIAssignableConcept<Iterator> >();
@@ -139,8 +134,7 @@ namespace boost_concepts {
   template <typename Iterator>
   class BidirectionalTraversalConcept {
   public:
-    typedef typename std::iterator_traits<Iterator>::iterator_category iterator_category;
-    typedef typename iterator_category::traversal traversal_category;
+    typedef typename boost::traversal_category<Iterator>::type traversal_category;
 
     void constraints() {
       boost::function_requires< ForwardTraversalConcept<Iterator> >();
@@ -157,8 +151,7 @@ namespace boost_concepts {
   template <typename Iterator>
   class RandomAccessTraversalConcept {
   public:
-    typedef typename std::iterator_traits<Iterator>::iterator_category iterator_category;
-    typedef typename iterator_category::traversal traversal_category;
+    typedef typename boost::traversal_category<Iterator>::type traversal_category;
     typedef typename std::iterator_traits<Iterator>::difference_type
       difference_type;
 
diff --git a/test/concept_tests.cpp b/test/concept_tests.cpp
index 1f67021..92e9162 100644
--- a/test/concept_tests.cpp
+++ b/test/concept_tests.cpp
@@ -6,14 +6,13 @@
 
 #include <boost/iterator/iterator_concepts.hpp>
 #include <boost/operators.hpp>
+#include <boost/static_assert.hpp> // remove
 
 struct new_iterator
-  : public boost::iterator<std::random_access_iterator_tag, int>,
-    public boost::new_iterator_base
+  : public boost::iterator< boost::iterator_tag<
+    boost::mutable_lvalue_iterator_tag
+    , boost::random_access_traversal_tag>, int>
 {
-  typedef boost::random_access_traversal_tag traversal_category;
-  typedef boost::mutable_lvalue_iterator_tag return_category;
-
   int& operator*() const { return *m_x; }
   new_iterator& operator++() { return *this; }
   new_iterator operator++(int) { return *this; }
@@ -58,22 +57,22 @@ main()
   boost::function_requires<
     boost_concepts::MutableLvalueIteratorConcept<int*> >();
   boost::function_requires<
-    boost_concepts::RandomAccessIteratorConcept<int*> >();
+    boost_concepts::RandomAccessTraversalConcept<int*> >();
 
   boost::function_requires<
     boost_concepts::ConstantLvalueIteratorConcept<const int*> >();
   boost::function_requires<
-    boost_concepts::RandomAccessIteratorConcept<const int*> >();
+    boost_concepts::RandomAccessTraversalConcept<const int*> >();
 #endif
 
   boost::function_requires<
     boost_concepts::MutableLvalueIteratorConcept<new_iterator> >();
   boost::function_requires<
-    boost_concepts::RandomAccessIteratorConcept<new_iterator> >();
+    boost_concepts::RandomAccessTraversalConcept<new_iterator> >();
 
   boost::function_requires<
     boost_concepts::MutableLvalueIteratorConcept<old_iterator> >();
   boost::function_requires<
-    boost_concepts::RandomAccessIteratorConcept<old_iterator> >();
+    boost_concepts::RandomAccessTraversalConcept<old_iterator> >();
   return 0;
 }