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/detail/enable_if.hpp> |
11 | #include <boost/iterator/iterator_adaptor.hpp> |
12 | #include <boost/iterator/iterator_categories.hpp> |
13 | #include <boost/mpl/not.hpp> |
14 | #include <boost/mpl/bool.hpp> |
15 | #include <boost/type_traits/function_traits.hpp> |
16 | #include <boost/type_traits/is_const.hpp> |
17 | #include <boost/type_traits/is_class.hpp> |
18 | #include <boost/type_traits/is_function.hpp> |
19 | #include <boost/type_traits/is_reference.hpp> |
20 | #include <boost/type_traits/remove_const.hpp> |
21 | #include <boost/type_traits/remove_reference.hpp> |
22 | #include <boost/utility/result_of.hpp> |
23 | |
24 | #include <iterator> |
25 | |
26 | #if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1310)) |
27 | # include <boost/type_traits/is_base_and_derived.hpp> |
28 | #endif |
29 | |
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 | #ifdef BOOST_RESULT_OF_USE_TR1 |
51 | , result_of<const UnaryFunc(typename std::iterator_traits<Iterator>::reference)> |
52 | #else |
53 | , result_of<const UnaryFunc&(typename std::iterator_traits<Iterator>::reference)> |
54 | #endif |
55 | >::type reference; |
56 | |
57 | // To get the default for Value: remove any reference on the |
58 | // result type, but retain any constness to signal |
59 | // non-writability. Note that if we adopt Thomas' suggestion |
60 | // to key non-writability *only* on the Reference argument, |
61 | // we'd need to strip constness here as well. |
62 | typedef typename ia_dflt_help< |
63 | Value |
64 | , remove_reference<reference> |
65 | >::type cv_value_type; |
66 | |
67 | public: |
68 | typedef iterator_adaptor< |
69 | transform_iterator<UnaryFunc, Iterator, Reference, Value> |
70 | , Iterator |
71 | , cv_value_type |
72 | , use_default // Leave the traversal category alone |
73 | , reference |
74 | > type; |
75 | }; |
76 | } |
77 | |
78 | template <class UnaryFunc, class Iterator, class Reference, class Value> |
79 | class transform_iterator |
80 | : public boost::iterators::detail::transform_iterator_base<UnaryFunc, Iterator, Reference, Value>::type |
81 | { |
82 | typedef typename |
83 | boost::iterators::detail::transform_iterator_base<UnaryFunc, Iterator, Reference, Value>::type |
84 | super_t; |
85 | |
86 | friend class iterator_core_access; |
87 | |
88 | public: |
89 | transform_iterator() { } |
90 | |
91 | transform_iterator(Iterator const& x, UnaryFunc f) |
92 | : super_t(x), m_f(f) { } |
93 | |
94 | explicit transform_iterator(Iterator const& x) |
95 | : super_t(x) |
96 | { |
97 | // Pro8 is a little too aggressive about instantiating the |
98 | // body of this function. |
99 | #if !BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003)) |
100 | // don't provide this constructor if UnaryFunc is a |
101 | // function pointer type, since it will be 0. Too dangerous. |
102 | BOOST_STATIC_ASSERT(is_class<UnaryFunc>::value); |
103 | #endif |
104 | } |
105 | |
106 | template < |
107 | class OtherUnaryFunction |
108 | , class OtherIterator |
109 | , class OtherReference |
110 | , class OtherValue> |
111 | transform_iterator( |
112 | transform_iterator<OtherUnaryFunction, OtherIterator, OtherReference, OtherValue> const& t |
113 | , typename enable_if_convertible<OtherIterator, Iterator>::type* = 0 |
114 | #if !BOOST_WORKAROUND(BOOST_MSVC, == 1310) |
115 | , typename enable_if_convertible<OtherUnaryFunction, UnaryFunc>::type* = 0 |
116 | #endif |
117 | ) |
118 | : super_t(t.base()), m_f(t.functor()) |
119 | {} |
120 | |
121 | UnaryFunc functor() const |
122 | { return m_f; } |
123 | |
124 | private: |
125 | typename super_t::reference dereference() const |
126 | { return m_f(*this->base()); } |
127 | |
128 | // Probably should be the initial base class so it can be |
129 | // optimized away via EBO if it is an empty class. |
130 | UnaryFunc m_f; |
131 | }; |
132 | |
133 | template <class UnaryFunc, class Iterator> |
134 | inline transform_iterator<UnaryFunc, Iterator> |
135 | make_transform_iterator(Iterator it, UnaryFunc fun) |
136 | { |
137 | return transform_iterator<UnaryFunc, Iterator>(it, fun); |
138 | } |
139 | |
140 | // Version which allows explicit specification of the UnaryFunc |
141 | // type. |
142 | // |
143 | // This generator is not provided if UnaryFunc is a function |
144 | // pointer type, because it's too dangerous: the default-constructed |
145 | // function pointer in the iterator be 0, leading to a runtime |
146 | // crash. |
147 | template <class UnaryFunc, class Iterator> |
148 | inline typename iterators::enable_if< |
149 | is_class<UnaryFunc> // We should probably find a cheaper test than is_class<> |
150 | , transform_iterator<UnaryFunc, Iterator> |
151 | >::type |
152 | make_transform_iterator(Iterator it) |
153 | { |
154 | return transform_iterator<UnaryFunc, Iterator>(it, UnaryFunc()); |
155 | } |
156 | |
157 | #if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION ) && !defined(BOOST_NO_FUNCTION_TEMPLATE_ORDERING) |
158 | template <class Return, class Argument, class Iterator> |
159 | inline transform_iterator< Return (*)(Argument), Iterator, Return> |
160 | make_transform_iterator(Iterator it, Return (*fun)(Argument)) |
161 | { |
162 | return transform_iterator<Return (*)(Argument), Iterator, Return>(it, fun); |
163 | } |
164 | #endif |
165 | |
166 | } // namespace iterators |
167 | |
168 | using iterators::transform_iterator; |
169 | using iterators::make_transform_iterator; |
170 | |
171 | } // namespace boost |
172 | |
173 | #include <boost/iterator/detail/config_undef.hpp> |
174 | |
175 | #endif // BOOST_TRANSFORM_ITERATOR_23022003THW_HPP |
176 | |