1// Boost.Range library
2//
3// Copyright Neil Groves 2007. 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_REPLACED_IF_IMPL_HPP_INCLUDED
12#define BOOST_RANGE_ADAPTOR_REPLACED_IF_IMPL_HPP_INCLUDED
13
14#include <boost/config.hpp>
15#include <boost/range/adaptor/argument_fwd.hpp>
16#include <boost/range/iterator_range.hpp>
17#include <boost/range/begin.hpp>
18#include <boost/range/end.hpp>
19#include <boost/range/value_type.hpp>
20#include <boost/range/concepts.hpp>
21#include <boost/iterator/iterator_adaptor.hpp>
22#include <boost/iterator/transform_iterator.hpp>
23#include <boost/optional/optional.hpp>
24
25namespace boost
26{
27 namespace range_detail
28 {
29 template< class Pred, class Value >
30 class replace_value_if
31 {
32 public:
33 typedef const Value& result_type;
34 typedef const Value& first_argument_type;
35
36 // Rationale:
37 // required to allow the iterator to be default constructible.
38 replace_value_if()
39 {
40 }
41
42 replace_value_if(const Pred& pred, const Value& to)
43 : m_impl(data(pred, to))
44 {
45 }
46
47 const Value& operator()(const Value& x) const
48 {
49 return m_impl->m_pred(x) ? m_impl->m_to : x;
50 }
51
52 private:
53 struct data
54 {
55 data(const Pred& p, const Value& t)
56 : m_pred(p), m_to(t)
57 {
58 }
59
60 Pred m_pred;
61 Value m_to;
62 };
63 boost::optional<data> m_impl;
64 };
65
66 template< class Pred, class R >
67 class replaced_if_range :
68 public boost::iterator_range<
69 boost::transform_iterator<
70 replace_value_if< Pred, BOOST_DEDUCED_TYPENAME range_value<R>::type >,
71 BOOST_DEDUCED_TYPENAME range_iterator<R>::type > >
72 {
73 private:
74 typedef replace_value_if< Pred, BOOST_DEDUCED_TYPENAME range_value<R>::type > Fn;
75
76 typedef boost::iterator_range<
77 boost::transform_iterator<
78 replace_value_if< Pred, BOOST_DEDUCED_TYPENAME range_value<R>::type >,
79 BOOST_DEDUCED_TYPENAME range_iterator<R>::type > > base_t;
80
81 public:
82 typedef BOOST_DEDUCED_TYPENAME range_value<R>::type value_type;
83
84 replaced_if_range( R& r, const Pred& pred, value_type to )
85 : base_t( make_transform_iterator( boost::begin(r), Fn(pred, to) ),
86 make_transform_iterator( boost::end(r), Fn(pred, to) ) )
87 { }
88 };
89
90 template< class Pred, class T >
91 class replace_if_holder
92 {
93 public:
94 replace_if_holder( const Pred& pred, const T& to )
95 : m_pred(pred), m_to(to)
96 { }
97
98 const Pred& pred() const { return m_pred; }
99 const T& to() const { return m_to; }
100
101 private:
102 Pred m_pred;
103 T m_to;
104 };
105
106 template< class Pred, class SinglePassRange >
107 inline replaced_if_range<Pred, SinglePassRange>
108 operator|(
109 SinglePassRange& r,
110 const replace_if_holder<
111 Pred,
112 BOOST_DEDUCED_TYPENAME range_value<SinglePassRange>::type>& f)
113 {
114 BOOST_RANGE_CONCEPT_ASSERT((
115 SinglePassRangeConcept<SinglePassRange>));
116
117 return replaced_if_range<Pred, SinglePassRange>(
118 r, f.pred(), f.to());
119 }
120
121 template< class Pred, class SinglePassRange >
122 inline replaced_if_range<Pred, const SinglePassRange>
123 operator|(
124 const SinglePassRange& r,
125 const replace_if_holder<
126 Pred,
127 BOOST_DEDUCED_TYPENAME range_value<SinglePassRange>::type>& f)
128 {
129 BOOST_RANGE_CONCEPT_ASSERT((
130 SinglePassRangeConcept<const SinglePassRange>));
131
132 return replaced_if_range<Pred, const SinglePassRange>(
133 r, f.pred(), f.to());
134 }
135 } // 'range_detail'
136
137 using range_detail::replaced_if_range;
138
139 namespace adaptors
140 {
141 namespace
142 {
143 const range_detail::forwarder2TU<range_detail::replace_if_holder>
144 replaced_if =
145 range_detail::forwarder2TU<range_detail::replace_if_holder>();
146 }
147
148 template<class Pred, class SinglePassRange>
149 inline replaced_if_range<Pred, SinglePassRange>
150 replace_if(SinglePassRange& rng, Pred pred,
151 BOOST_DEDUCED_TYPENAME range_value<SinglePassRange>::type to)
152 {
153 BOOST_RANGE_CONCEPT_ASSERT((
154 SinglePassRangeConcept<SinglePassRange>));
155
156 return range_detail::replaced_if_range<Pred, SinglePassRange>(
157 rng, pred, to);
158 }
159
160 template<class Pred, class SinglePassRange>
161 inline replaced_if_range<Pred, const SinglePassRange>
162 replace_if(
163 const SinglePassRange& rng,
164 Pred pred,
165 BOOST_DEDUCED_TYPENAME range_value<const SinglePassRange>::type to)
166 {
167 BOOST_RANGE_CONCEPT_ASSERT((
168 SinglePassRangeConcept<const SinglePassRange>));
169
170 return range_detail::replaced_if_range<Pred, const SinglePassRange>(
171 rng, pred, to);
172 }
173 } // 'adaptors'
174
175} // 'boost'
176
177#endif // include guard
178