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