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1 | // (C) Copyright David Abrahams 2002. |
2 | // (C) Copyright Jeremy Siek 2002. | |
3 | // (C) Copyright Thomas Witt 2002. | |
4 | // Distributed under the Boost Software License, Version 1.0. (See | |
5 | // accompanying file LICENSE_1_0.txt or copy at | |
6 | // http://www.boost.org/LICENSE_1_0.txt) | |
7 | #ifndef BOOST_TRANSFORM_ITERATOR_23022003THW_HPP | |
8 | #define BOOST_TRANSFORM_ITERATOR_23022003THW_HPP | |
9 | ||
10 | #include <boost/iterator.hpp> | |
11 | #include <boost/iterator/detail/enable_if.hpp> | |
12 | #include <boost/iterator/iterator_adaptor.hpp> | |
13 | #include <boost/iterator/iterator_categories.hpp> | |
14 | #include <boost/mpl/not.hpp> | |
15 | #include <boost/mpl/bool.hpp> | |
16 | #include <boost/type_traits/function_traits.hpp> | |
17 | #include <boost/type_traits/is_const.hpp> | |
18 | #include <boost/type_traits/is_class.hpp> | |
19 | #include <boost/type_traits/is_function.hpp> | |
20 | #include <boost/type_traits/is_reference.hpp> | |
21 | #include <boost/type_traits/remove_const.hpp> | |
22 | #include <boost/type_traits/remove_reference.hpp> | |
23 | #include <boost/utility/result_of.hpp> | |
24 | ||
25 | ||
26 | #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1310)) | |
27 | # include <boost/type_traits/is_base_and_derived.hpp> | |
28 | ||
29 | #endif | |
30 | #include <boost/iterator/detail/config_def.hpp> | |
31 | ||
32 | ||
33 | namespace boost { | |
34 | namespace iterators { | |
35 | ||
36 | template <class UnaryFunction, class Iterator, class Reference = use_default, class Value = use_default> | |
37 | class transform_iterator; | |
38 | ||
39 | namespace detail | |
40 | { | |
41 | // Compute the iterator_adaptor instantiation to be used for transform_iterator | |
42 | template <class UnaryFunc, class Iterator, class Reference, class Value> | |
43 | struct transform_iterator_base | |
44 | { | |
45 | private: | |
46 | // By default, dereferencing the iterator yields the same as | |
47 | // the function. | |
48 | typedef typename ia_dflt_help< | |
49 | Reference | |
50 | , result_of<const UnaryFunc(typename std::iterator_traits<Iterator>::reference)> | |
51 | >::type reference; | |
52 | ||
53 | // To get the default for Value: remove any reference on the | |
54 | // result type, but retain any constness to signal | |
55 | // non-writability. Note that if we adopt Thomas' suggestion | |
56 | // to key non-writability *only* on the Reference argument, | |
57 | // we'd need to strip constness here as well. | |
58 | typedef typename ia_dflt_help< | |
59 | Value | |
60 | , remove_reference<reference> | |
61 | >::type cv_value_type; | |
62 | ||
63 | public: | |
64 | typedef iterator_adaptor< | |
65 | transform_iterator<UnaryFunc, Iterator, Reference, Value> | |
66 | , Iterator | |
67 | , cv_value_type | |
68 | , use_default // Leave the traversal category alone | |
69 | , reference | |
70 | > type; | |
71 | }; | |
72 | } | |
73 | ||
74 | template <class UnaryFunc, class Iterator, class Reference, class Value> | |
75 | class transform_iterator | |
76 | : public boost::iterators::detail::transform_iterator_base<UnaryFunc, Iterator, Reference, Value>::type | |
77 | { | |
78 | typedef typename | |
79 | boost::iterators::detail::transform_iterator_base<UnaryFunc, Iterator, Reference, Value>::type | |
80 | super_t; | |
81 | ||
82 | friend class iterator_core_access; | |
83 | ||
84 | public: | |
85 | transform_iterator() { } | |
86 | ||
87 | transform_iterator(Iterator const& x, UnaryFunc f) | |
88 | : super_t(x), m_f(f) { } | |
89 | ||
90 | explicit transform_iterator(Iterator const& x) | |
91 | : super_t(x) | |
92 | { | |
93 | // Pro8 is a little too aggressive about instantiating the | |
94 | // body of this function. | |
95 | #if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) | |
96 | // don't provide this constructor if UnaryFunc is a | |
97 | // function pointer type, since it will be 0. Too dangerous. | |
98 | BOOST_STATIC_ASSERT(is_class<UnaryFunc>::value); | |
99 | #endif | |
100 | } | |
101 | ||
102 | template < | |
103 | class OtherUnaryFunction | |
104 | , class OtherIterator | |
105 | , class OtherReference | |
106 | , class OtherValue> | |
107 | transform_iterator( | |
108 | transform_iterator<OtherUnaryFunction, OtherIterator, OtherReference, OtherValue> const& t | |
109 | , typename enable_if_convertible<OtherIterator, Iterator>::type* = 0 | |
110 | #if !BOOST_WORKAROUND(BOOST_MSVC, == 1310) | |
111 | , typename enable_if_convertible<OtherUnaryFunction, UnaryFunc>::type* = 0 | |
112 | #endif | |
113 | ) | |
114 | : super_t(t.base()), m_f(t.functor()) | |
115 | {} | |
116 | ||
117 | UnaryFunc functor() const | |
118 | { return m_f; } | |
119 | ||
120 | private: | |
121 | typename super_t::reference dereference() const | |
122 | { return m_f(*this->base()); } | |
123 | ||
124 | // Probably should be the initial base class so it can be | |
125 | // optimized away via EBO if it is an empty class. | |
126 | UnaryFunc m_f; | |
127 | }; | |
128 | ||
129 | template <class UnaryFunc, class Iterator> | |
130 | inline transform_iterator<UnaryFunc, Iterator> | |
131 | make_transform_iterator(Iterator it, UnaryFunc fun) | |
132 | { | |
133 | return transform_iterator<UnaryFunc, Iterator>(it, fun); | |
134 | } | |
135 | ||
136 | // Version which allows explicit specification of the UnaryFunc | |
137 | // type. | |
138 | // | |
139 | // This generator is not provided if UnaryFunc is a function | |
140 | // pointer type, because it's too dangerous: the default-constructed | |
141 | // function pointer in the iterator be 0, leading to a runtime | |
142 | // crash. | |
143 | template <class UnaryFunc, class Iterator> | |
144 | inline typename iterators::enable_if< | |
145 | is_class<UnaryFunc> // We should probably find a cheaper test than is_class<> | |
146 | , transform_iterator<UnaryFunc, Iterator> | |
147 | >::type | |
148 | make_transform_iterator(Iterator it) | |
149 | { | |
150 | return transform_iterator<UnaryFunc, Iterator>(it, UnaryFunc()); | |
151 | } | |
152 | ||
153 | #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION ) && !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING) | |
154 | template <class Return, class Argument, class Iterator> | |
155 | inline transform_iterator< Return (*)(Argument), Iterator, Return> | |
156 | make_transform_iterator(Iterator it, Return (*fun)(Argument)) | |
157 | { | |
158 | return transform_iterator<Return (*)(Argument), Iterator, Return>(it, fun); | |
159 | } | |
160 | #endif | |
161 | ||
162 | } // namespace iterators | |
163 | ||
164 | using iterators::transform_iterator; | |
165 | using iterators::make_transform_iterator; | |
166 | ||
167 | } // namespace boost | |
168 | ||
169 | #include <boost/iterator/detail/config_undef.hpp> | |
170 | ||
171 | #endif // BOOST_TRANSFORM_ITERATOR_23022003THW_HPP |