Made implementation work, if is_convertible

is not supported.
Moved categories in new detail header.
Introduced category detection metafunctions.


[SVN r829]

include/boost/iterator/detail/categories.hpp

@@ -0,0 +1,318 @@
+// (C) Copyright Thomas Witt 2002. Permission to copy, use, modify,
+// sell and distribute this software is granted provided this
+// copyright notice appears in all copies. This software is provided
+// "as is" without express or implied warranty, and with no claim as
+// to its suitability for any purpose.
+
+#ifndef BOOST_ITERATOR_DETAIL_CATEGORIES_HPP
+#define BOOST_ITERATOR_DETAIL_CATEGORIES_HPP
+
+#include <boost/config.hpp>
+#include <boost/detail/workaround.hpp>
+#include <boost/type_traits/conversion_traits.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/mpl/bool_c.hpp>
+#include <boost/mpl/logical/or.hpp>
+#include <iterator>
+
+#if BOOST_WORKAROUND(__MWERKS__, <=0x2407)
+#  define BOOST_NO_IS_CONVERTIBLE // "Convertible does not provide enough/is not working"
+#endif
+
+namespace boost {
+
+  // Return Type Categories
+  struct readable_iterator_tag { };
+  struct writable_iterator_tag { };
+  struct swappable_iterator_tag : 
+    virtual public readable_iterator_tag, // Not sure about this change -JGS
+    virtual public writable_iterator_tag { };
+  struct constant_lvalue_iterator_tag : 
+    virtual public readable_iterator_tag { };
+  struct mutable_lvalue_iterator_tag : 
+    virtual public swappable_iterator_tag,
+    virtual public constant_lvalue_iterator_tag { };
+
+  // Traversal Categories
+  struct input_traversal_tag { };
+  struct output_traversal_tag { };
+  struct forward_traversal_tag : virtual public input_traversal_tag, 
+    virtual public output_traversal_tag { };
+  struct bidirectional_traversal_tag : virtual public forward_traversal_tag { };
+  struct random_access_traversal_tag : virtual public bidirectional_traversal_tag { };
+
+  struct error_iterator_tag { };
+
+  namespace detail
+  {
+    //
+    // Tag detection meta functions
+    //
+    // Needed to work with compilers
+    // without working is_convertible
+    //
+
+#ifndef BOOST_NO_IS_CONVERTIBLE
+    template <class Category>
+    struct is_input_iterator :
+      is_convertible<Category*, std::input_iterator_tag*>
+    {
+    };
+
+    template <class Category>
+    struct is_output_iterator :
+      is_convertible<Category*, std::output_iterator_tag*>
+    {
+    };
+
+    template <class Category>
+    struct is_forward_iterator :
+      is_convertible<Category*, std::forward_iterator_tag*>
+    {
+    };
+
+    template <class Category>
+    struct is_bidirectional_iterator :
+      is_convertible<Category*, std::bidirectional_iterator_tag*>
+    {
+    };
+
+    template <class Category>
+    struct is_random_access_iterator :
+      is_convertible<Category*, std::random_access_iterator_tag*>
+    {
+    };
+
+    template <class Category>
+    struct is_readable_iterator :
+      is_convertible<Category*, readable_iterator_tag*>
+    { };
+
+    template <class Category>
+    struct is_writable_iterator :
+      is_convertible<Category*, writable_iterator_tag*>
+    { };
+
+    template <class Category>
+    struct is_swappable_iterator :
+      is_convertible<Category*, swappable_iterator_tag*>
+    { };
+
+    template <class Category>
+    struct is_constant_lvalue_iterator :
+      is_convertible<Category*, constant_lvalue_iterator_tag*>
+    { };
+
+    template <class Category>
+    struct is_mutable_lvalue_iterator :
+      is_convertible<Category*, mutable_lvalue_iterator_tag*>
+    { };
+
+    template <class Category>
+    struct is_input_traversal_iterator :
+      is_convertible<Category*, input_traversal_tag*>
+    { };
+
+    template <class Category>
+    struct is_output_traversal_iterator :
+      is_convertible<Category*, output_traversal_tag*>
+    { };
+
+    template <class Category>
+    struct is_forward_traversal_iterator :
+      is_convertible<Category*, forward_traversal_tag*>
+    { };
+
+    template <class Category>
+    struct is_bidirectional_traversal_iterator :
+      is_convertible<Category*, bidirectional_traversal_tag*>
+    { };
+
+    template <class Category>
+    struct is_random_access_traversal_iterator :
+      is_convertible<Category*, random_access_traversal_tag*>
+    { };
+
+#else
+    //
+    // We cannot detect the iterator category for custom
+    // tag types. For custom tag types false_c is returned
+    //
+    // As a result the std iterator category detection functions
+    // can't detect the iterator category of the new iterator_tag template.
+    //
+
+    //
+    // std iterator categories
+    //
+
+    template <class Category>
+    struct is_random_access_iterator :
+      mpl::false_c
+    {};
+
+    template <>
+    struct is_random_access_iterator<std::random_access_iterator_tag> :
+      mpl::true_c
+    {};
+
+    template <class Category>
+    struct is_bidirectional_iterator :
+      is_random_access_iterator< Category >
+    {};
+
+    template <>
+    struct is_bidirectional_iterator<std::bidirectional_iterator_tag> :
+      mpl::true_c
+    {};
+
+    template <class Category>
+    struct is_forward_iterator :
+      is_bidirectional_iterator< Category >
+    {};
+
+    template <>
+    struct is_forward_iterator<std::forward_iterator_tag> :
+      mpl::true_c
+    {};
+
+    template <class Category>
+    struct is_output_iterator :
+      is_forward_iterator< Category >
+    {};
+
+    template <>
+    struct is_output_iterator<std::output_iterator_tag> :
+      mpl::true_c
+    {};
+
+    template <class Category>
+    struct is_input_iterator :
+      is_forward_iterator< Category >
+    {};
+
+    template <>
+    struct is_input_iterator<std::input_iterator_tag> :
+      mpl::true_c
+    {};
+
+    //
+    // Return type
+    //
+
+    template <class Category>
+    struct is_mutable_lvalue_iterator :
+      mpl::false_c
+    {};
+
+    template <>
+    struct is_mutable_lvalue_iterator<mutable_lvalue_iterator_tag> :
+      mpl::true_c
+    {};
+
+    template <class Category>
+    struct is_constant_lvalue_iterator :
+      is_mutable_lvalue_iterator<Category>
+    {};
+
+    template <>
+    struct is_constant_lvalue_iterator<constant_lvalue_iterator_tag> :
+      mpl::true_c 
+    {};
+
+    template <class Category>
+    struct is_swappable_iterator :
+      is_constant_lvalue_iterator<Category>
+    {};
+
+    template <>
+    struct is_swappable_iterator<swappable_iterator_tag> :
+      mpl::true_c 
+    {};
+
+    template <class Category>
+    struct is_readable_iterator :
+      mpl::logical_or< is_swappable_iterator<Category>,
+                       is_constant_lvalue_iterator<Category> >
+    {};
+
+    template <>
+    struct is_readable_iterator<readable_iterator_tag> :
+      mpl::true_c 
+    {};
+
+    template <class Category>
+    struct is_writable_iterator :
+      is_swappable_iterator<Category>
+    {};
+
+    template <>
+    struct is_writable_iterator<writable_iterator_tag> :
+      mpl::true_c 
+    {};
+
+    //
+    // Traversal
+    //
+
+    template <class Category>
+    struct is_random_access_traversal_iterator :
+      mpl::false_c
+    {};
+
+    template <>
+    struct is_random_access_traversal_iterator<random_access_traversal_tag> :
+      mpl::true_c
+    {};
+
+    template <class Category>
+    struct is_bidirectional_traversal_iterator :
+      is_random_access_traversal_iterator< Category >
+    {};
+
+    template <>
+    struct is_bidirectional_traversal_iterator<bidirectional_traversal_tag> :
+      mpl::true_c
+    {};
+
+    template <class Category>
+    struct is_forward_traversal_iterator :
+      is_bidirectional_traversal_iterator< Category >
+    {};
+
+    template <>
+    struct is_forward_traversal_iterator<forward_traversal_tag> :
+      mpl::true_c
+    {};
+
+    template <class Category>
+    struct is_input_traversal_iterator :
+      is_forward_traversal_iterator< Category >
+    {};
+
+    template <>
+    struct is_input_traversal_iterator<input_traversal_tag> :
+      mpl::true_c
+    {};
+
+    template <class Category>
+    struct is_output_traversal_iterator :
+      is_forward_traversal_iterator< Category >
+    {};
+
+    template <>
+    struct is_output_traversal_iterator<output_traversal_tag> :
+      mpl::true_c
+    {};
+
+#endif
+
+  } // namespace detail
+
+} // namespace boost
+
+#ifdef BOOST_NO_IS_CONVERTIBLE
+#  undef BOOST_NO_IS_CONVERTIBLE
+#endif
+
+#endif // BOOST_ITERATOR_DETAIL_CATEGORIES_HPP

include/boost/iterator/iterator_categories.hpp

@@ -11,41 +11,26 @@
 #define BOOST_ITERATOR_CATEGORIES_HPP
 
 #include <boost/config.hpp>
+#include <boost/iterator/detail/categories.hpp>
 #include <boost/type_traits/conversion_traits.hpp>
 #include <boost/type_traits/cv_traits.hpp>
 #include <boost/detail/iterator.hpp>
+#include <boost/detail/workaround.hpp>
 #include <boost/mpl/apply_if.hpp>
 #include <boost/mpl/if.hpp>
 #include <boost/mpl/bool_c.hpp>
 #include <boost/mpl/aux_/has_xxx.hpp>
+#include <boost/mpl/logical/not.hpp>
 #include <boost/mpl/logical/or.hpp>
 #include <boost/mpl/logical/and.hpp>
 #include <iterator>
 
+#if BOOST_WORKAROUND(__MWERKS__, <=0x2407)
+#  define BOOST_NO_IS_CONVERTIBLE // "Convertible does not provide enough/is not working"
+#endif
+
 namespace boost {
 
-  // Return Type Categories
-  struct readable_iterator_tag { };
-  struct writable_iterator_tag { };
-  struct swappable_iterator_tag : 
-    virtual public readable_iterator_tag, // Not sure about this change -JGS
-    virtual public writable_iterator_tag { };
-  struct constant_lvalue_iterator_tag : 
-    virtual public readable_iterator_tag { };
-  struct mutable_lvalue_iterator_tag : 
-    virtual public swappable_iterator_tag,
-    virtual public constant_lvalue_iterator_tag { };
-
-  // Traversal Categories
-  struct input_traversal_tag { };
-  struct output_traversal_tag { };
-  struct forward_traversal_tag : virtual public input_traversal_tag, 
-    virtual public output_traversal_tag { };
-  struct bidirectional_traversal_tag : virtual public forward_traversal_tag { };
-  struct random_access_traversal_tag : virtual public bidirectional_traversal_tag { };
-
-  struct error_iterator_tag { };
-
   // When creating new iterators, you have three options. 
 
   // 1) The recommended option is to specialize the return_category
@@ -85,13 +70,13 @@ namespace boost {
     template <typename Category, typename ValueType>
     struct iter_category_to_return
         : mpl::if_<
-           is_convertible<Category*, std::forward_iterator_tag*>
+           is_forward_iterator<Category>
            , typename choose_lvalue_return<ValueType>::type
            , typename mpl::if_<
-                is_convertible<Category*, std::input_iterator_tag*>
+                is_input_iterator<Category>
                 , boost::readable_iterator_tag
                 , typename mpl::if_<
-                    is_convertible<Category*, std::output_iterator_tag*>
+                    is_output_iterator<Category>
                     , boost::writable_iterator_tag
                     , boost::error_iterator_tag
                   >::type
@@ -103,16 +88,16 @@ namespace boost {
     template <typename Category>
     struct iter_category_to_traversal
       : mpl::if_<
-          is_convertible<Category*, std::random_access_iterator_tag*>
+          is_random_access_iterator<Category>
           , random_access_traversal_tag
           , typename mpl::if_<
-              is_convertible<Category*, std::bidirectional_iterator_tag*>
+              is_bidirectional_iterator<Category>
               , bidirectional_traversal_tag
               , typename mpl::if_<
-                  is_convertible<Category*, std::forward_iterator_tag*>
+                  is_forward_iterator<Category>
                   , forward_traversal_tag
                   , typename mpl::if_<
-                      is_convertible<Category*, std::input_iterator_tag*>
+                      is_input_iterator<Category>
                       , input_traversal_tag
                       , output_traversal_tag
                     >::type
@@ -122,6 +107,23 @@ namespace boost {
     {
     };
 
+#if BOOST_WORKAROUND(__MWERKS__, <=0x2407) 
+    //
+    // has_traversal fails for cwpro7, so we have to use 
+    // something less sophisticated.
+    // 
+    // The solution depends on the fact that only
+    // std iterator categories work with is_xxx_iterator
+    // meta functions, as BOOST_NO_IS_CONVERTIBLE is
+    // defined for cwpro7.
+    //
+    template <class Tag>
+    struct is_new_iterator_tag :
+      mpl::logical_and< mpl::logical_not< is_input_iterator<Tag> >,
+                        mpl::logical_not< is_output_iterator<Tag> > >
+    {};
+
+#else
   BOOST_MPL_HAS_XXX_TRAIT_DEF(traversal)
 
     template <class Tag>
@@ -133,6 +135,9 @@ namespace boost {
           , mpl::bool_c<false> >::type
     {
     };
+
+#endif
+
   } // namespace detail
   
   namespace detail {
@@ -202,21 +207,23 @@ namespace boost {
 
 #endif
 
+  // TODO Fix this for BOOST_NO_IS_CONVERTIBLE
+
   template <class RC, class TC>
   struct cvt_iterator_category
       : mpl::if_<
           mpl::logical_or<
-             is_convertible<RC*, mutable_lvalue_iterator_tag*>
+             detail::is_mutable_lvalue_iterator<RC>
-             , is_convertible<RC*, constant_lvalue_iterator_tag*>
+             , detail::is_constant_lvalue_iterator<RC>
           >
           , typename mpl::if_<
-              is_convertible<TC*, random_access_traversal_tag*>
+              detail::is_random_access_traversal_iterator<TC>
               , std::random_access_iterator_tag
               , typename mpl::if_<
-                  is_convertible<TC*, bidirectional_traversal_tag*>
+                  detail::is_bidirectional_traversal_iterator<TC>
                   , std::bidirectional_iterator_tag
                   , typename mpl::if_<
-                      is_convertible<TC*, forward_traversal_tag*>
+                      detail::is_forward_traversal_iterator<TC>
                       , std::forward_iterator_tag
                       , error_iterator_tag
                     >::type
@@ -225,14 +232,14 @@ namespace boost {
 
           , typename mpl::if_<
             mpl::logical_and<
-               is_convertible<RC*, readable_iterator_tag*>
+               detail::is_readable_iterator<RC>
-               , is_convertible<TC*, input_traversal_tag*>
+               , detail::is_input_traversal_iterator<TC>
             >
             , std::input_iterator_tag
             , typename mpl::if_<
                 mpl::logical_and<
-                  is_convertible<RC*, writable_iterator_tag*>
+                  detail::is_writable_iterator<RC>
-                  , is_convertible<TC*, output_traversal_tag*>
+                  , detail::is_output_traversal_iterator<TC>
                 >
                 , std::output_iterator_tag
                 , error_iterator_tag
@@ -249,7 +256,10 @@ namespace boost {
     typedef TraversalTag traversal;
   };
 
-
 } // namespace boost
 
+#ifdef BOOST_NO_IS_CONVERTIBLE
+#  undef BOOST_NO_IS_CONVERTIBLE
+#endif
+
 #endif // BOOST_ITERATOR_CATEGORIES_HPP