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
22#include <boost/utility/enable_if.hpp>
23#include <boost/type_traits/make_unsigned.hpp>
24#include <boost/type_traits/remove_const.hpp>
25#include <cstddef>
26#include <utility>
27
28namespace boost
29{
30 namespace detail
31 {
32
33 //////////////////////////////////////////////////////////////////////////
34 // default
35 //////////////////////////////////////////////////////////////////////////
36
37 template<typename T>
38 class has_size_type
39 {
40 typedef char no_type;
41 struct yes_type { char dummy[2]; };
42
43 template<typename C>
44 static yes_type test(BOOST_DEDUCED_TYPENAME C::size_type x);
45
46 template<typename C>
47 static no_type test(...);
48
49 public:
50 static const bool value = sizeof(test<T>(0)) == sizeof(yes_type);
51 };
52
53 template<typename C, typename Enabler=void>
54 struct range_size
55 {
56 typedef BOOST_DEDUCED_TYPENAME make_unsigned<
57 BOOST_DEDUCED_TYPENAME range_difference<C>::type
58 >::type type;
59 };
60
61 template<typename C>
62 struct range_size<
63 C,
64 BOOST_DEDUCED_TYPENAME ::boost::enable_if<has_size_type<C>, void>::type
65 >
66 {
67 typedef BOOST_DEDUCED_TYPENAME C::size_type type;
68 };
69
70 }
71
72 template< class T >
73 struct range_size :
74 detail::range_size<T>
75 {
76// Very strange things happen on some compilers that have the range concept
77// asserts disabled. This preprocessor condition is clearly redundant on a
78// working compiler but is vital for at least some compilers such as clang 4.2
79// but only on the Mac!
80#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT == 1
81 BOOST_RANGE_CONCEPT_ASSERT((boost::SinglePassRangeConcept<T>));
82#endif
83 };
84
85 template< class T >
86 struct range_size<const T >
87 : detail::range_size<T>
88 {
89#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT == 1
90 BOOST_RANGE_CONCEPT_ASSERT((boost::SinglePassRangeConcept<T>));
91#endif
92 };
93
94} // namespace boost
95
96
97
98#endif
99