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
29namespace 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

source code of include/boost/range/size_type.hpp