1 // Boost.Range library
2 //
3 //  Copyright Thorsten Ottosen 2003-2004. Use, modification and
4 //  distribution is subject to the Boost Software License, Version
5 //  1.0. (See accompanying file LICENSE_1_0.txt or copy at
6 //  http://www.boost.org/LICENSE_1_0.txt)
7 //
8 // For more information, see http://www.boost.org/libs/range/
9 //
10 
11 #ifndef BOOST_RANGE_SIZE_TYPE_HPP
12 #define BOOST_RANGE_SIZE_TYPE_HPP
13 
14 #if defined(_MSC_VER)
15 # pragma once
16 #endif
17 
18 #include <boost/range/config.hpp>
19 #include <boost/range/difference_type.hpp>
20 #include <boost/range/concepts.hpp>
21 #include <boost/range/has_range_iterator.hpp>
22 
23 #include <boost/utility/enable_if.hpp>
24 #include <boost/type_traits/make_unsigned.hpp>
25 #include <boost/type_traits/remove_const.hpp>
26 #include <cstddef>
27 #include <utility>
28 
29 namespace boost
30 {
31     namespace detail
32     {
33 
34         //////////////////////////////////////////////////////////////////////////
35         // default
36         //////////////////////////////////////////////////////////////////////////
37 
38         template<typename T>
39         class has_size_type
40         {
41             typedef char no_type;
42             struct yes_type { char dummy[2]; };
43 
44             template<typename C>
45             static yes_type test(BOOST_DEDUCED_TYPENAME C::size_type x);
46 
47             template<typename C>
48             static no_type test(...);
49 
50         public:
51             static const bool value = sizeof(test<T>(0)) == sizeof(yes_type);
52         };
53 
54         template<typename C, typename Enabler=void>
55         struct range_size_
56         {
57             typedef BOOST_DEDUCED_TYPENAME make_unsigned<
58                 BOOST_DEDUCED_TYPENAME range_difference<C>::type
59             >::type type;
60         };
61 
62         template<typename C>
63         struct range_size_<
64             C,
65             BOOST_DEDUCED_TYPENAME ::boost::enable_if<has_size_type<C>, void>::type
66         >
67         {
68             typedef BOOST_DEDUCED_TYPENAME C::size_type type;
69         };
70 
71         template<typename C, bool B = range_detail::has_type< range_iterator<C> >::value>
72         struct range_size
73         { };
74 
75         template<typename C>
76         struct range_size<C, true>
77           : range_size_<C>
78         { };
79     }
80 
81     template< class T >
82     struct range_size :
83         detail::range_size<T>
84     { };
85 
86 } // namespace boost
87 
88 
89 
90 #endif
91