1// Boost.Range library
2//
3// Copyright Thorsten Ottosen, Neil Groves 2006 - 2008. 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_ADAPTOR_TRANSFORMED_HPP
12#define BOOST_RANGE_ADAPTOR_TRANSFORMED_HPP
13
14#include <boost/range/adaptor/argument_fwd.hpp>
15#include <boost/range/detail/default_constructible_unary_fn.hpp>
16#include <boost/range/iterator_range.hpp>
17#include <boost/range/concepts.hpp>
18#include <boost/iterator/transform_iterator.hpp>
19#include <boost/utility/result_of.hpp>
20
21namespace boost
22{
23 namespace range_detail
24 {
25 // A type generator to produce the transform_iterator type conditionally
26 // including a wrapped predicate as appropriate.
27 template<typename P, typename It>
28 struct transform_iterator_gen
29 {
30 typedef transform_iterator<
31 typename default_constructible_unary_fn_gen<
32 P,
33 typename transform_iterator<P, It>::reference
34 >::type,
35 It
36 > type;
37 };
38
39 template< class F, class R >
40 struct transformed_range :
41 public boost::iterator_range<
42 typename transform_iterator_gen<
43 F, typename range_iterator<R>::type>::type>
44 {
45 private:
46 typedef typename transform_iterator_gen<
47 F, typename range_iterator<R>::type>::type transform_iter_t;
48
49 typedef boost::iterator_range<transform_iter_t> base;
50
51 public:
52 typedef typename default_constructible_unary_fn_gen<
53 F,
54 typename transform_iterator<
55 F,
56 typename range_iterator<R>::type
57 >::reference
58 >::type transform_fn_type;
59
60 typedef R source_range_type;
61
62 transformed_range(transform_fn_type f, R& r)
63 : base(transform_iter_t(boost::begin(r), f),
64 transform_iter_t(boost::end(r), f))
65 {
66 }
67 };
68
69 template< class T >
70 struct transform_holder : holder<T>
71 {
72 transform_holder( T r ) : holder<T>(r)
73 {
74 }
75 };
76
77 template< class SinglePassRange, class UnaryFunction >
78 inline transformed_range<UnaryFunction,SinglePassRange>
79 operator|( SinglePassRange& r,
80 const transform_holder<UnaryFunction>& f )
81 {
82 BOOST_RANGE_CONCEPT_ASSERT((
83 SinglePassRangeConcept<SinglePassRange>));
84
85 return transformed_range<UnaryFunction,SinglePassRange>( f.val, r );
86 }
87
88 template< class SinglePassRange, class UnaryFunction >
89 inline transformed_range<UnaryFunction, const SinglePassRange>
90 operator|( const SinglePassRange& r,
91 const transform_holder<UnaryFunction>& f )
92 {
93 BOOST_RANGE_CONCEPT_ASSERT((
94 SinglePassRangeConcept<const SinglePassRange>));
95
96 return transformed_range<UnaryFunction, const SinglePassRange>(
97 f.val, r);
98 }
99
100 } // 'range_detail'
101
102 using range_detail::transformed_range;
103
104 namespace adaptors
105 {
106 namespace
107 {
108 const range_detail::forwarder<range_detail::transform_holder>
109 transformed =
110 range_detail::forwarder<range_detail::transform_holder>();
111 }
112
113 template<class UnaryFunction, class SinglePassRange>
114 inline transformed_range<UnaryFunction, SinglePassRange>
115 transform(SinglePassRange& rng, UnaryFunction fn)
116 {
117 BOOST_RANGE_CONCEPT_ASSERT((
118 SinglePassRangeConcept<SinglePassRange>));
119
120 return transformed_range<UnaryFunction, SinglePassRange>(fn, rng);
121 }
122
123 template<class UnaryFunction, class SinglePassRange>
124 inline transformed_range<UnaryFunction, const SinglePassRange>
125 transform(const SinglePassRange& rng, UnaryFunction fn)
126 {
127 BOOST_RANGE_CONCEPT_ASSERT((
128 SinglePassRangeConcept<const SinglePassRange>));
129
130 return transformed_range<UnaryFunction, const SinglePassRange>(
131 fn, rng);
132 }
133 } // 'adaptors'
134
135}
136
137#endif
138

source code of boost/boost/range/adaptor/transformed.hpp