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1 | // Boost string_algo library join.hpp header file ---------------------------// |
2 | ||
3 | // Copyright Pavol Droba 2002-2006. | |
4 | // | |
5 | // Distributed under the Boost Software License, Version 1.0. | |
6 | // (See accompanying file LICENSE_1_0.txt or copy at | |
7 | // http://www.boost.org/LICENSE_1_0.txt) | |
8 | ||
9 | // See http://www.boost.org/ for updates, documentation, and revision history. | |
10 | ||
11 | #ifndef BOOST_STRING_JOIN_HPP | |
12 | #define BOOST_STRING_JOIN_HPP | |
13 | ||
14 | #include <boost/algorithm/string/config.hpp> | |
15 | #include <boost/algorithm/string/detail/sequence.hpp> | |
16 | #include <boost/range/value_type.hpp> | |
17 | #include <boost/range/as_literal.hpp> | |
18 | ||
19 | /*! \file | |
20 | Defines join algorithm. | |
21 | ||
22 | Join algorithm is a counterpart to split algorithms. | |
23 | It joins strings from a 'list' by adding user defined separator. | |
24 | Additionally there is a version that allows simple filtering | |
25 | by providing a predicate. | |
26 | */ | |
27 | ||
28 | namespace boost { | |
29 | namespace algorithm { | |
30 | ||
31 | // join --------------------------------------------------------------// | |
32 | ||
33 | //! Join algorithm | |
34 | /*! | |
35 | This algorithm joins all strings in a 'list' into one long string. | |
36 | Segments are concatenated by given separator. | |
37 | ||
38 | \param Input A container that holds the input strings. It must be a container-of-containers. | |
39 | \param Separator A string that will separate the joined segments. | |
40 | \return Concatenated string. | |
41 | ||
42 | \note This function provides the strong exception-safety guarantee | |
43 | */ | |
44 | template< typename SequenceSequenceT, typename Range1T> | |
45 | inline typename range_value<SequenceSequenceT>::type | |
46 | join( | |
47 | const SequenceSequenceT& Input, | |
48 | const Range1T& Separator) | |
49 | { | |
50 | // Define working types | |
51 | typedef typename range_value<SequenceSequenceT>::type ResultT; | |
52 | typedef typename range_const_iterator<SequenceSequenceT>::type InputIteratorT; | |
53 | ||
54 | // Parse input | |
55 | InputIteratorT itBegin=::boost::begin(Input); | |
56 | InputIteratorT itEnd=::boost::end(Input); | |
57 | ||
58 | // Construct container to hold the result | |
59 | ResultT Result; | |
60 | ||
61 | // Append first element | |
62 | if(itBegin!=itEnd) | |
63 | { | |
64 | detail::insert(Result, ::boost::end(Result), *itBegin); | |
65 | ++itBegin; | |
66 | } | |
67 | ||
68 | for(;itBegin!=itEnd; ++itBegin) | |
69 | { | |
70 | // Add separator | |
71 | detail::insert(Result, ::boost::end(Result), ::boost::as_literal(Separator)); | |
72 | // Add element | |
73 | detail::insert(Result, ::boost::end(Result), *itBegin); | |
74 | } | |
75 | ||
76 | return Result; | |
77 | } | |
78 | ||
79 | // join_if ----------------------------------------------------------// | |
80 | ||
81 | //! Conditional join algorithm | |
82 | /*! | |
83 | This algorithm joins all strings in a 'list' into one long string. | |
84 | Segments are concatenated by given separator. Only segments that | |
85 | satisfy the predicate will be added to the result. | |
86 | ||
87 | \param Input A container that holds the input strings. It must be a container-of-containers. | |
88 | \param Separator A string that will separate the joined segments. | |
89 | \param Pred A segment selection predicate | |
90 | \return Concatenated string. | |
91 | ||
92 | \note This function provides the strong exception-safety guarantee | |
93 | */ | |
94 | template< typename SequenceSequenceT, typename Range1T, typename PredicateT> | |
95 | inline typename range_value<SequenceSequenceT>::type | |
96 | join_if( | |
97 | const SequenceSequenceT& Input, | |
98 | const Range1T& Separator, | |
99 | PredicateT Pred) | |
100 | { | |
101 | // Define working types | |
102 | typedef typename range_value<SequenceSequenceT>::type ResultT; | |
103 | typedef typename range_const_iterator<SequenceSequenceT>::type InputIteratorT; | |
104 | ||
105 | // Parse input | |
106 | InputIteratorT itBegin=::boost::begin(Input); | |
107 | InputIteratorT itEnd=::boost::end(Input); | |
108 | ||
109 | // Construct container to hold the result | |
110 | ResultT Result; | |
111 | ||
112 | // Roll to the first element that will be added | |
113 | while(itBegin!=itEnd && !Pred(*itBegin)) ++itBegin; | |
114 | // Add this element | |
115 | if(itBegin!=itEnd) | |
116 | { | |
117 | detail::insert(Result, ::boost::end(Result), *itBegin); | |
118 | ++itBegin; | |
119 | } | |
120 | ||
121 | for(;itBegin!=itEnd; ++itBegin) | |
122 | { | |
123 | if(Pred(*itBegin)) | |
124 | { | |
125 | // Add separator | |
126 | detail::insert(Result, ::boost::end(Result), ::boost::as_literal(Separator)); | |
127 | // Add element | |
128 | detail::insert(Result, ::boost::end(Result), *itBegin); | |
129 | } | |
130 | } | |
131 | ||
132 | return Result; | |
133 | } | |
134 | ||
135 | } // namespace algorithm | |
136 | ||
137 | // pull names to the boost namespace | |
138 | using algorithm::join; | |
139 | using algorithm::join_if; | |
140 | ||
141 | } // namespace boost | |
142 | ||
143 | ||
144 | #endif // BOOST_STRING_JOIN_HPP | |
145 |