<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/xhtml;charset=UTF-8"/> <meta http-equiv="X-UA-Compatible" content="IE=9"/> <meta name="generator" content="Doxygen 1.8.13"/> <meta name="viewport" content="width=device-width, initial-scale=1"/> <title>libstdc++: regex_executor.tcc Source File</title> <link href="tabs.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="jquery.js"></script> <script type="text/javascript" src="dynsections.js"></script> <link href="navtree.css" rel="stylesheet" type="text/css"/> <script type="text/javascript" src="resize.js"></script> <script type="text/javascript" src="navtreedata.js"></script> <script type="text/javascript" src="navtree.js"></script> <script type="text/javascript"> $(document).ready(initResizable); </script> <link href="doxygen.css" rel="stylesheet" type="text/css" /> </head> <body> <div id="top"><!-- do not remove this div, it is closed by doxygen! --> <div id="titlearea"> <table cellspacing="0" cellpadding="0"> <tbody> <tr style="height: 56px;"> <td id="projectalign" style="padding-left: 0.5em;"> <div id="projectname">libstdc++ </div> </td> </tr> </tbody> </table> </div> <!-- end header part --> <!-- Generated by Doxygen 1.8.13 --> </div><!-- top --> <div id="side-nav" class="ui-resizable side-nav-resizable"> <div id="nav-tree"> <div id="nav-tree-contents"> <div id="nav-sync" class="sync"></div> </div> </div> <div id="splitbar" style="-moz-user-select:none;" class="ui-resizable-handle"> </div> </div> <script type="text/javascript"> $(document).ready(function(){initNavTree('a00458_source.html','');}); </script> <div id="doc-content"> <div class="header"> <div class="headertitle"> <div class="title">regex_executor.tcc</div> </div> </div><!--header--> <div class="contents"> <a href="a00458.html">Go to the documentation of this file.</a><div class="fragment"><div class="line"><a name="l00001"></a><span class="lineno"> 1</span> <span class="comment">// class template regex -*- C++ -*-</span></div><div class="line"><a name="l00002"></a><span class="lineno"> 2</span> </div><div class="line"><a name="l00003"></a><span class="lineno"> 3</span> <span class="comment">// Copyright (C) 2013-2015 Free Software Foundation, Inc.</span></div><div class="line"><a name="l00004"></a><span class="lineno"> 4</span> <span class="comment">//</span></div><div class="line"><a name="l00005"></a><span class="lineno"> 5</span> <span class="comment">// This file is part of the GNU ISO C++ Library. This library is free</span></div><div class="line"><a name="l00006"></a><span class="lineno"> 6</span> <span class="comment">// software; you can redistribute it and/or modify it under the</span></div><div class="line"><a name="l00007"></a><span class="lineno"> 7</span> <span class="comment">// terms of the GNU General Public License as published by the</span></div><div class="line"><a name="l00008"></a><span class="lineno"> 8</span> <span class="comment">// Free Software Foundation; either version 3, or (at your option)</span></div><div class="line"><a name="l00009"></a><span class="lineno"> 9</span> <span class="comment">// any later version.</span></div><div class="line"><a name="l00010"></a><span class="lineno"> 10</span> </div><div class="line"><a name="l00011"></a><span class="lineno"> 11</span> <span class="comment">// This library is distributed in the hope that it will be useful,</span></div><div class="line"><a name="l00012"></a><span class="lineno"> 12</span> <span class="comment">// but WITHOUT ANY WARRANTY; without even the implied warranty of</span></div><div class="line"><a name="l00013"></a><span class="lineno"> 13</span> <span class="comment">// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the</span></div><div class="line"><a name="l00014"></a><span class="lineno"> 14</span> <span class="comment">// GNU General Public License for more details.</span></div><div class="line"><a name="l00015"></a><span class="lineno"> 15</span> </div><div class="line"><a name="l00016"></a><span class="lineno"> 16</span> <span class="comment">// Under Section 7 of GPL version 3, you are granted additional</span></div><div class="line"><a name="l00017"></a><span class="lineno"> 17</span> <span class="comment">// permissions described in the GCC Runtime Library Exception, version</span></div><div class="line"><a name="l00018"></a><span class="lineno"> 18</span> <span class="comment">// 3.1, as published by the Free Software Foundation.</span></div><div class="line"><a name="l00019"></a><span class="lineno"> 19</span> </div><div class="line"><a name="l00020"></a><span class="lineno"> 20</span> <span class="comment">// You should have received a copy of the GNU General Public License and</span></div><div class="line"><a name="l00021"></a><span class="lineno"> 21</span> <span class="comment">// a copy of the GCC Runtime Library Exception along with this program;</span></div><div class="line"><a name="l00022"></a><span class="lineno"> 22</span> <span class="comment">// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see</span></div><div class="line"><a name="l00023"></a><span class="lineno"> 23</span> <span class="comment">// <http://www.gnu.org/licenses/>.</span></div><div class="line"><a name="l00024"></a><span class="lineno"> 24</span> <span class="comment"></span></div><div class="line"><a name="l00025"></a><span class="lineno"> 25</span> <span class="comment">/**</span></div><div class="line"><a name="l00026"></a><span class="lineno"> 26</span> <span class="comment"> * @file bits/regex_executor.tcc</span></div><div class="line"><a name="l00027"></a><span class="lineno"> 27</span> <span class="comment"> * This is an internal header file, included by other library headers.</span></div><div class="line"><a name="l00028"></a><span class="lineno"> 28</span> <span class="comment"> * Do not attempt to use it directly. @headername{regex}</span></div><div class="line"><a name="l00029"></a><span class="lineno"> 29</span> <span class="comment"> */</span></div><div class="line"><a name="l00030"></a><span class="lineno"> 30</span> </div><div class="line"><a name="l00031"></a><span class="lineno"> 31</span> <span class="keyword">namespace </span><a class="code" href="a01487.html">std</a> _GLIBCXX_VISIBILITY(default)</div><div class="line"><a name="l00032"></a><span class="lineno"> 32</span> {</div><div class="line"><a name="l00033"></a><span class="lineno"> 33</span> <span class="keyword">namespace </span>__detail</div><div class="line"><a name="l00034"></a><span class="lineno"> 34</span> {</div><div class="line"><a name="l00035"></a><span class="lineno"> 35</span> _GLIBCXX_BEGIN_NAMESPACE_VERSION</div><div class="line"><a name="l00036"></a><span class="lineno"> 36</span> </div><div class="line"><a name="l00037"></a><span class="lineno"> 37</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _BiIter, <span class="keyword">typename</span> _Alloc, <span class="keyword">typename</span> _TraitsT,</div><div class="line"><a name="l00038"></a><span class="lineno"> 38</span>  <span class="keywordtype">bool</span> __dfs_mode></div><div class="line"><a name="l00039"></a><span class="lineno"> 39</span>  <span class="keywordtype">bool</span> _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::</div><div class="line"><a name="l00040"></a><span class="lineno"> 40</span>  _M_search()</div><div class="line"><a name="l00041"></a><span class="lineno"> 41</span>  {</div><div class="line"><a name="l00042"></a><span class="lineno"> 42</span>  <span class="keywordflow">if</span> (_M_search_from_first())</div><div class="line"><a name="l00043"></a><span class="lineno"> 43</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div><div class="line"><a name="l00044"></a><span class="lineno"> 44</span>  <span class="keywordflow">if</span> (_M_flags & <a class="code" href="a01511.html#a905d343797be96365d8d663cfc7411f2">regex_constants::match_continuous</a>)</div><div class="line"><a name="l00045"></a><span class="lineno"> 45</span>  <span class="keywordflow">return</span> <span class="keyword">false</span>;</div><div class="line"><a name="l00046"></a><span class="lineno"> 46</span>  _M_flags |= <a class="code" href="a01511.html#ad730b04e961da111de1dc350953f48ba">regex_constants::match_prev_avail</a>;</div><div class="line"><a name="l00047"></a><span class="lineno"> 47</span>  <span class="keywordflow">while</span> (_M_begin != _M_end)</div><div class="line"><a name="l00048"></a><span class="lineno"> 48</span>  {</div><div class="line"><a name="l00049"></a><span class="lineno"> 49</span>  ++_M_begin;</div><div class="line"><a name="l00050"></a><span class="lineno"> 50</span>  <span class="keywordflow">if</span> (_M_search_from_first())</div><div class="line"><a name="l00051"></a><span class="lineno"> 51</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div><div class="line"><a name="l00052"></a><span class="lineno"> 52</span>  }</div><div class="line"><a name="l00053"></a><span class="lineno"> 53</span>  <span class="keywordflow">return</span> <span class="keyword">false</span>;</div><div class="line"><a name="l00054"></a><span class="lineno"> 54</span>  }</div><div class="line"><a name="l00055"></a><span class="lineno"> 55</span> </div><div class="line"><a name="l00056"></a><span class="lineno"> 56</span>  <span class="comment">// The _M_main function operates in different modes, DFS mode or BFS mode,</span></div><div class="line"><a name="l00057"></a><span class="lineno"> 57</span>  <span class="comment">// indicated by template parameter __dfs_mode, and dispatches to one of the</span></div><div class="line"><a name="l00058"></a><span class="lineno"> 58</span>  <span class="comment">// _M_main_dispatch overloads.</span></div><div class="line"><a name="l00059"></a><span class="lineno"> 59</span>  <span class="comment">//</span></div><div class="line"><a name="l00060"></a><span class="lineno"> 60</span>  <span class="comment">// ------------------------------------------------------------</span></div><div class="line"><a name="l00061"></a><span class="lineno"> 61</span>  <span class="comment">//</span></div><div class="line"><a name="l00062"></a><span class="lineno"> 62</span>  <span class="comment">// DFS mode:</span></div><div class="line"><a name="l00063"></a><span class="lineno"> 63</span>  <span class="comment">//</span></div><div class="line"><a name="l00064"></a><span class="lineno"> 64</span>  <span class="comment">// It applies a Depth-First-Search (aka backtracking) on given NFA and input</span></div><div class="line"><a name="l00065"></a><span class="lineno"> 65</span>  <span class="comment">// string.</span></div><div class="line"><a name="l00066"></a><span class="lineno"> 66</span>  <span class="comment">// At the very beginning the executor stands in the start state, then it</span></div><div class="line"><a name="l00067"></a><span class="lineno"> 67</span>  <span class="comment">// tries every possible state transition in current state recursively. Some</span></div><div class="line"><a name="l00068"></a><span class="lineno"> 68</span>  <span class="comment">// state transitions consume input string, say, a single-char-matcher or a</span></div><div class="line"><a name="l00069"></a><span class="lineno"> 69</span>  <span class="comment">// back-reference matcher; some don't, like assertion or other anchor nodes.</span></div><div class="line"><a name="l00070"></a><span class="lineno"> 70</span>  <span class="comment">// When the input is exhausted and/or the current state is an accepting</span></div><div class="line"><a name="l00071"></a><span class="lineno"> 71</span>  <span class="comment">// state, the whole executor returns true.</span></div><div class="line"><a name="l00072"></a><span class="lineno"> 72</span>  <span class="comment">//</span></div><div class="line"><a name="l00073"></a><span class="lineno"> 73</span>  <span class="comment">// TODO: This approach is exponentially slow for certain input.</span></div><div class="line"><a name="l00074"></a><span class="lineno"> 74</span>  <span class="comment">// Try to compile the NFA to a DFA.</span></div><div class="line"><a name="l00075"></a><span class="lineno"> 75</span>  <span class="comment">//</span></div><div class="line"><a name="l00076"></a><span class="lineno"> 76</span>  <span class="comment">// Time complexity: \Omega(match_length), O(2^(_M_nfa.size()))</span></div><div class="line"><a name="l00077"></a><span class="lineno"> 77</span>  <span class="comment">// Space complexity: \theta(match_results.size() + match_length)</span></div><div class="line"><a name="l00078"></a><span class="lineno"> 78</span>  <span class="comment">//</span></div><div class="line"><a name="l00079"></a><span class="lineno"> 79</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _BiIter, <span class="keyword">typename</span> _Alloc, <span class="keyword">typename</span> _TraitsT,</div><div class="line"><a name="l00080"></a><span class="lineno"> 80</span>  <span class="keywordtype">bool</span> __dfs_mode></div><div class="line"><a name="l00081"></a><span class="lineno"> 81</span>  <span class="keywordtype">bool</span> _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::</div><div class="line"><a name="l00082"></a><span class="lineno"> 82</span>  _M_main_dispatch(_Match_mode __match_mode, __dfs)</div><div class="line"><a name="l00083"></a><span class="lineno"> 83</span>  {</div><div class="line"><a name="l00084"></a><span class="lineno"> 84</span>  _M_has_sol = <span class="keyword">false</span>;</div><div class="line"><a name="l00085"></a><span class="lineno"> 85</span>  *_M_states._M_get_sol_pos() = _BiIter();</div><div class="line"><a name="l00086"></a><span class="lineno"> 86</span>  _M_cur_results = _M_results;</div><div class="line"><a name="l00087"></a><span class="lineno"> 87</span>  _M_dfs(__match_mode, _M_states._M_start);</div><div class="line"><a name="l00088"></a><span class="lineno"> 88</span>  <span class="keywordflow">return</span> _M_has_sol;</div><div class="line"><a name="l00089"></a><span class="lineno"> 89</span>  }</div><div class="line"><a name="l00090"></a><span class="lineno"> 90</span> </div><div class="line"><a name="l00091"></a><span class="lineno"> 91</span>  <span class="comment">// ------------------------------------------------------------</span></div><div class="line"><a name="l00092"></a><span class="lineno"> 92</span>  <span class="comment">//</span></div><div class="line"><a name="l00093"></a><span class="lineno"> 93</span>  <span class="comment">// BFS mode:</span></div><div class="line"><a name="l00094"></a><span class="lineno"> 94</span>  <span class="comment">//</span></div><div class="line"><a name="l00095"></a><span class="lineno"> 95</span>  <span class="comment">// Russ Cox's article (http://swtch.com/~rsc/regexp/regexp1.html)</span></div><div class="line"><a name="l00096"></a><span class="lineno"> 96</span>  <span class="comment">// explained this algorithm clearly.</span></div><div class="line"><a name="l00097"></a><span class="lineno"> 97</span>  <span class="comment">//</span></div><div class="line"><a name="l00098"></a><span class="lineno"> 98</span>  <span class="comment">// It first computes epsilon closure (states that can be achieved without</span></div><div class="line"><a name="l00099"></a><span class="lineno"> 99</span>  <span class="comment">// consuming characters) for every state that's still matching,</span></div><div class="line"><a name="l00100"></a><span class="lineno"> 100</span>  <span class="comment">// using the same DFS algorithm, but doesn't re-enter states (using</span></div><div class="line"><a name="l00101"></a><span class="lineno"> 101</span>  <span class="comment">// _M_states._M_visited to check), nor follow _S_opcode_match.</span></div><div class="line"><a name="l00102"></a><span class="lineno"> 102</span>  <span class="comment">//</span></div><div class="line"><a name="l00103"></a><span class="lineno"> 103</span>  <span class="comment">// Then apply DFS using every _S_opcode_match (in _M_states._M_match_queue)</span></div><div class="line"><a name="l00104"></a><span class="lineno"> 104</span>  <span class="comment">// as the start state.</span></div><div class="line"><a name="l00105"></a><span class="lineno"> 105</span>  <span class="comment">//</span></div><div class="line"><a name="l00106"></a><span class="lineno"> 106</span>  <span class="comment">// It significantly reduces potential duplicate states, so has a better</span></div><div class="line"><a name="l00107"></a><span class="lineno"> 107</span>  <span class="comment">// upper bound; but it requires more overhead.</span></div><div class="line"><a name="l00108"></a><span class="lineno"> 108</span>  <span class="comment">//</span></div><div class="line"><a name="l00109"></a><span class="lineno"> 109</span>  <span class="comment">// Time complexity: \Omega(match_length * match_results.size())</span></div><div class="line"><a name="l00110"></a><span class="lineno"> 110</span>  <span class="comment">// O(match_length * _M_nfa.size() * match_results.size())</span></div><div class="line"><a name="l00111"></a><span class="lineno"> 111</span>  <span class="comment">// Space complexity: \Omega(_M_nfa.size() + match_results.size())</span></div><div class="line"><a name="l00112"></a><span class="lineno"> 112</span>  <span class="comment">// O(_M_nfa.size() * match_results.size())</span></div><div class="line"><a name="l00113"></a><span class="lineno"> 113</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _BiIter, <span class="keyword">typename</span> _Alloc, <span class="keyword">typename</span> _TraitsT,</div><div class="line"><a name="l00114"></a><span class="lineno"> 114</span>  <span class="keywordtype">bool</span> __dfs_mode></div><div class="line"><a name="l00115"></a><span class="lineno"> 115</span>  <span class="keywordtype">bool</span> _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::</div><div class="line"><a name="l00116"></a><span class="lineno"> 116</span>  _M_main_dispatch(_Match_mode __match_mode, __bfs)</div><div class="line"><a name="l00117"></a><span class="lineno"> 117</span>  {</div><div class="line"><a name="l00118"></a><span class="lineno"> 118</span>  _M_states._M_queue(_M_states._M_start, _M_results);</div><div class="line"><a name="l00119"></a><span class="lineno"> 119</span>  <span class="keywordtype">bool</span> __ret = <span class="keyword">false</span>;</div><div class="line"><a name="l00120"></a><span class="lineno"> 120</span>  <span class="keywordflow">while</span> (1)</div><div class="line"><a name="l00121"></a><span class="lineno"> 121</span>  {</div><div class="line"><a name="l00122"></a><span class="lineno"> 122</span>  _M_has_sol = <span class="keyword">false</span>;</div><div class="line"><a name="l00123"></a><span class="lineno"> 123</span>  <span class="keywordflow">if</span> (_M_states._M_match_queue.empty())</div><div class="line"><a name="l00124"></a><span class="lineno"> 124</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00125"></a><span class="lineno"> 125</span>  <a class="code" href="a01434.html#ga0af400b776b8486401daf6ecf91bacca">std::fill_n</a>(_M_states._M_visited_states.get(), _M_nfa.size(), <span class="keyword">false</span>);</div><div class="line"><a name="l00126"></a><span class="lineno"> 126</span>  <span class="keyword">auto</span> __old_queue = std::move(_M_states._M_match_queue);</div><div class="line"><a name="l00127"></a><span class="lineno"> 127</span>  <span class="keywordflow">for</span> (<span class="keyword">auto</span>& __task : __old_queue)</div><div class="line"><a name="l00128"></a><span class="lineno"> 128</span>  {</div><div class="line"><a name="l00129"></a><span class="lineno"> 129</span>  _M_cur_results = std::move(__task.second);</div><div class="line"><a name="l00130"></a><span class="lineno"> 130</span>  _M_dfs(__match_mode, __task.first);</div><div class="line"><a name="l00131"></a><span class="lineno"> 131</span>  }</div><div class="line"><a name="l00132"></a><span class="lineno"> 132</span>  <span class="keywordflow">if</span> (__match_mode == _Match_mode::_Prefix)</div><div class="line"><a name="l00133"></a><span class="lineno"> 133</span>  __ret |= _M_has_sol;</div><div class="line"><a name="l00134"></a><span class="lineno"> 134</span>  <span class="keywordflow">if</span> (_M_current == _M_end)</div><div class="line"><a name="l00135"></a><span class="lineno"> 135</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00136"></a><span class="lineno"> 136</span>  ++_M_current;</div><div class="line"><a name="l00137"></a><span class="lineno"> 137</span>  }</div><div class="line"><a name="l00138"></a><span class="lineno"> 138</span>  <span class="keywordflow">if</span> (__match_mode == _Match_mode::_Exact)</div><div class="line"><a name="l00139"></a><span class="lineno"> 139</span>  __ret = _M_has_sol;</div><div class="line"><a name="l00140"></a><span class="lineno"> 140</span>  _M_states._M_match_queue.clear();</div><div class="line"><a name="l00141"></a><span class="lineno"> 141</span>  <span class="keywordflow">return</span> __ret;</div><div class="line"><a name="l00142"></a><span class="lineno"> 142</span>  }</div><div class="line"><a name="l00143"></a><span class="lineno"> 143</span> </div><div class="line"><a name="l00144"></a><span class="lineno"> 144</span>  <span class="comment">// Return whether now match the given sub-NFA.</span></div><div class="line"><a name="l00145"></a><span class="lineno"> 145</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _BiIter, <span class="keyword">typename</span> _Alloc, <span class="keyword">typename</span> _TraitsT,</div><div class="line"><a name="l00146"></a><span class="lineno"> 146</span>  <span class="keywordtype">bool</span> __dfs_mode></div><div class="line"><a name="l00147"></a><span class="lineno"> 147</span>  <span class="keywordtype">bool</span> _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::</div><div class="line"><a name="l00148"></a><span class="lineno"> 148</span>  _M_lookahead(_State<_TraitsT> __state)</div><div class="line"><a name="l00149"></a><span class="lineno"> 149</span>  {</div><div class="line"><a name="l00150"></a><span class="lineno"> 150</span>  <span class="comment">// Backreferences may refer to captured content.</span></div><div class="line"><a name="l00151"></a><span class="lineno"> 151</span>  <span class="comment">// We may want to make this faster by not copying,</span></div><div class="line"><a name="l00152"></a><span class="lineno"> 152</span>  <span class="comment">// but let's not be clever prematurely.</span></div><div class="line"><a name="l00153"></a><span class="lineno"> 153</span>  _ResultsVec __what(_M_cur_results);</div><div class="line"><a name="l00154"></a><span class="lineno"> 154</span>  _Executor __sub(_M_current, _M_end, __what, _M_re, _M_flags);</div><div class="line"><a name="l00155"></a><span class="lineno"> 155</span>  __sub._M_states._M_start = __state._M_alt;</div><div class="line"><a name="l00156"></a><span class="lineno"> 156</span>  <span class="keywordflow">if</span> (__sub._M_search_from_first())</div><div class="line"><a name="l00157"></a><span class="lineno"> 157</span>  {</div><div class="line"><a name="l00158"></a><span class="lineno"> 158</span>  <span class="keywordflow">for</span> (<span class="keywordtype">size_t</span> __i = 0; __i < __what.size(); __i++)</div><div class="line"><a name="l00159"></a><span class="lineno"> 159</span>  <span class="keywordflow">if</span> (__what[__i].matched)</div><div class="line"><a name="l00160"></a><span class="lineno"> 160</span>  _M_cur_results[__i] = __what[__i];</div><div class="line"><a name="l00161"></a><span class="lineno"> 161</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div><div class="line"><a name="l00162"></a><span class="lineno"> 162</span>  }</div><div class="line"><a name="l00163"></a><span class="lineno"> 163</span>  <span class="keywordflow">return</span> <span class="keyword">false</span>;</div><div class="line"><a name="l00164"></a><span class="lineno"> 164</span>  }</div><div class="line"><a name="l00165"></a><span class="lineno"> 165</span> </div><div class="line"><a name="l00166"></a><span class="lineno"> 166</span>  <span class="comment">// __rep_count records how many times (__rep_count.second)</span></div><div class="line"><a name="l00167"></a><span class="lineno"> 167</span>  <span class="comment">// this node is visited under certain input iterator</span></div><div class="line"><a name="l00168"></a><span class="lineno"> 168</span>  <span class="comment">// (__rep_count.first). This prevent the executor from entering</span></div><div class="line"><a name="l00169"></a><span class="lineno"> 169</span>  <span class="comment">// infinite loop by refusing to continue when it's already been</span></div><div class="line"><a name="l00170"></a><span class="lineno"> 170</span>  <span class="comment">// visited more than twice. It's `twice` instead of `once` because</span></div><div class="line"><a name="l00171"></a><span class="lineno"> 171</span>  <span class="comment">// we need to spare one more time for potential group capture.</span></div><div class="line"><a name="l00172"></a><span class="lineno"> 172</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _BiIter, <span class="keyword">typename</span> _Alloc, <span class="keyword">typename</span> _TraitsT,</div><div class="line"><a name="l00173"></a><span class="lineno"> 173</span>  <span class="keywordtype">bool</span> __dfs_mode></div><div class="line"><a name="l00174"></a><span class="lineno"> 174</span>  <span class="keywordtype">void</span> _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::</div><div class="line"><a name="l00175"></a><span class="lineno"> 175</span>  _M_rep_once_more(_Match_mode __match_mode, _StateIdT __i)</div><div class="line"><a name="l00176"></a><span class="lineno"> 176</span>  {</div><div class="line"><a name="l00177"></a><span class="lineno"> 177</span>  <span class="keyword">const</span> <span class="keyword">auto</span>& __state = _M_nfa[__i];</div><div class="line"><a name="l00178"></a><span class="lineno"> 178</span>  <span class="keyword">auto</span>& __rep_count = _M_rep_count[__i];</div><div class="line"><a name="l00179"></a><span class="lineno"> 179</span>  <span class="keywordflow">if</span> (__rep_count.second == 0 || __rep_count.first != _M_current)</div><div class="line"><a name="l00180"></a><span class="lineno"> 180</span>  {</div><div class="line"><a name="l00181"></a><span class="lineno"> 181</span>  <span class="keyword">auto</span> __back = __rep_count;</div><div class="line"><a name="l00182"></a><span class="lineno"> 182</span>  __rep_count.first = _M_current;</div><div class="line"><a name="l00183"></a><span class="lineno"> 183</span>  __rep_count.second = 1;</div><div class="line"><a name="l00184"></a><span class="lineno"> 184</span>  _M_dfs(__match_mode, __state._M_alt);</div><div class="line"><a name="l00185"></a><span class="lineno"> 185</span>  __rep_count = __back;</div><div class="line"><a name="l00186"></a><span class="lineno"> 186</span>  }</div><div class="line"><a name="l00187"></a><span class="lineno"> 187</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00188"></a><span class="lineno"> 188</span>  {</div><div class="line"><a name="l00189"></a><span class="lineno"> 189</span>  <span class="keywordflow">if</span> (__rep_count.second < 2)</div><div class="line"><a name="l00190"></a><span class="lineno"> 190</span>  {</div><div class="line"><a name="l00191"></a><span class="lineno"> 191</span>  __rep_count.second++;</div><div class="line"><a name="l00192"></a><span class="lineno"> 192</span>  _M_dfs(__match_mode, __state._M_alt);</div><div class="line"><a name="l00193"></a><span class="lineno"> 193</span>  __rep_count.second--;</div><div class="line"><a name="l00194"></a><span class="lineno"> 194</span>  }</div><div class="line"><a name="l00195"></a><span class="lineno"> 195</span>  }</div><div class="line"><a name="l00196"></a><span class="lineno"> 196</span>  };</div><div class="line"><a name="l00197"></a><span class="lineno"> 197</span> </div><div class="line"><a name="l00198"></a><span class="lineno"> 198</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _BiIter, <span class="keyword">typename</span> _Alloc, <span class="keyword">typename</span> _TraitsT,</div><div class="line"><a name="l00199"></a><span class="lineno"> 199</span>  <span class="keywordtype">bool</span> __dfs_mode></div><div class="line"><a name="l00200"></a><span class="lineno"> 200</span>  <span class="keywordtype">void</span> _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::</div><div class="line"><a name="l00201"></a><span class="lineno"> 201</span>  _M_dfs(_Match_mode __match_mode, _StateIdT __i)</div><div class="line"><a name="l00202"></a><span class="lineno"> 202</span>  {</div><div class="line"><a name="l00203"></a><span class="lineno"> 203</span>  <span class="keywordflow">if</span> (_M_states._M_visited(__i))</div><div class="line"><a name="l00204"></a><span class="lineno"> 204</span>  <span class="keywordflow">return</span>;</div><div class="line"><a name="l00205"></a><span class="lineno"> 205</span> </div><div class="line"><a name="l00206"></a><span class="lineno"> 206</span>  <span class="keyword">const</span> <span class="keyword">auto</span>& __state = _M_nfa[__i];</div><div class="line"><a name="l00207"></a><span class="lineno"> 207</span>  <span class="comment">// Every change on _M_cur_results and _M_current will be rolled back after</span></div><div class="line"><a name="l00208"></a><span class="lineno"> 208</span>  <span class="comment">// finishing the recursion step.</span></div><div class="line"><a name="l00209"></a><span class="lineno"> 209</span>  <span class="keywordflow">switch</span> (__state._M_opcode)</div><div class="line"><a name="l00210"></a><span class="lineno"> 210</span>  {</div><div class="line"><a name="l00211"></a><span class="lineno"> 211</span>  <span class="comment">// _M_alt branch is "match once more", while _M_next is "get me out</span></div><div class="line"><a name="l00212"></a><span class="lineno"> 212</span>  <span class="comment">// of this quantifier". Executing _M_next first or _M_alt first don't</span></div><div class="line"><a name="l00213"></a><span class="lineno"> 213</span>  <span class="comment">// mean the same thing, and we need to choose the correct order under</span></div><div class="line"><a name="l00214"></a><span class="lineno"> 214</span>  <span class="comment">// given greedy mode.</span></div><div class="line"><a name="l00215"></a><span class="lineno"> 215</span>  <span class="keywordflow">case</span> _S_opcode_repeat:</div><div class="line"><a name="l00216"></a><span class="lineno"> 216</span>  {</div><div class="line"><a name="l00217"></a><span class="lineno"> 217</span>  <span class="comment">// Greedy.</span></div><div class="line"><a name="l00218"></a><span class="lineno"> 218</span>  <span class="keywordflow">if</span> (!__state._M_neg)</div><div class="line"><a name="l00219"></a><span class="lineno"> 219</span>  {</div><div class="line"><a name="l00220"></a><span class="lineno"> 220</span>  _M_rep_once_more(__match_mode, __i);</div><div class="line"><a name="l00221"></a><span class="lineno"> 221</span>  <span class="comment">// If it's DFS executor and already accepted, we're done.</span></div><div class="line"><a name="l00222"></a><span class="lineno"> 222</span>  <span class="keywordflow">if</span> (!__dfs_mode || !_M_has_sol)</div><div class="line"><a name="l00223"></a><span class="lineno"> 223</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00224"></a><span class="lineno"> 224</span>  }</div><div class="line"><a name="l00225"></a><span class="lineno"> 225</span>  <span class="keywordflow">else</span> <span class="comment">// Non-greedy mode</span></div><div class="line"><a name="l00226"></a><span class="lineno"> 226</span>  {</div><div class="line"><a name="l00227"></a><span class="lineno"> 227</span>  <span class="keywordflow">if</span> (__dfs_mode)</div><div class="line"><a name="l00228"></a><span class="lineno"> 228</span>  {</div><div class="line"><a name="l00229"></a><span class="lineno"> 229</span>  <span class="comment">// vice-versa.</span></div><div class="line"><a name="l00230"></a><span class="lineno"> 230</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00231"></a><span class="lineno"> 231</span>  <span class="keywordflow">if</span> (!_M_has_sol)</div><div class="line"><a name="l00232"></a><span class="lineno"> 232</span>  _M_rep_once_more(__match_mode, __i);</div><div class="line"><a name="l00233"></a><span class="lineno"> 233</span>  }</div><div class="line"><a name="l00234"></a><span class="lineno"> 234</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00235"></a><span class="lineno"> 235</span>  {</div><div class="line"><a name="l00236"></a><span class="lineno"> 236</span>  <span class="comment">// DON'T attempt anything, because there's already another</span></div><div class="line"><a name="l00237"></a><span class="lineno"> 237</span>  <span class="comment">// state with higher priority accepted. This state cannot</span></div><div class="line"><a name="l00238"></a><span class="lineno"> 238</span>  <span class="comment">// be better by attempting its next node.</span></div><div class="line"><a name="l00239"></a><span class="lineno"> 239</span>  <span class="keywordflow">if</span> (!_M_has_sol)</div><div class="line"><a name="l00240"></a><span class="lineno"> 240</span>  {</div><div class="line"><a name="l00241"></a><span class="lineno"> 241</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00242"></a><span class="lineno"> 242</span>  <span class="comment">// DON'T attempt anything if it's already accepted. An</span></div><div class="line"><a name="l00243"></a><span class="lineno"> 243</span>  <span class="comment">// accepted state *must* be better than a solution that</span></div><div class="line"><a name="l00244"></a><span class="lineno"> 244</span>  <span class="comment">// matches a non-greedy quantifier one more time.</span></div><div class="line"><a name="l00245"></a><span class="lineno"> 245</span>  <span class="keywordflow">if</span> (!_M_has_sol)</div><div class="line"><a name="l00246"></a><span class="lineno"> 246</span>  _M_rep_once_more(__match_mode, __i);</div><div class="line"><a name="l00247"></a><span class="lineno"> 247</span>  }</div><div class="line"><a name="l00248"></a><span class="lineno"> 248</span>  }</div><div class="line"><a name="l00249"></a><span class="lineno"> 249</span>  }</div><div class="line"><a name="l00250"></a><span class="lineno"> 250</span>  }</div><div class="line"><a name="l00251"></a><span class="lineno"> 251</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00252"></a><span class="lineno"> 252</span>  <span class="keywordflow">case</span> _S_opcode_subexpr_begin:</div><div class="line"><a name="l00253"></a><span class="lineno"> 253</span>  {</div><div class="line"><a name="l00254"></a><span class="lineno"> 254</span>  <span class="keyword">auto</span>& __res = _M_cur_results[__state._M_subexpr];</div><div class="line"><a name="l00255"></a><span class="lineno"> 255</span>  <span class="keyword">auto</span> __back = __res.first;</div><div class="line"><a name="l00256"></a><span class="lineno"> 256</span>  __res.first = _M_current;</div><div class="line"><a name="l00257"></a><span class="lineno"> 257</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00258"></a><span class="lineno"> 258</span>  __res.first = __back;</div><div class="line"><a name="l00259"></a><span class="lineno"> 259</span>  }</div><div class="line"><a name="l00260"></a><span class="lineno"> 260</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00261"></a><span class="lineno"> 261</span>  <span class="keywordflow">case</span> _S_opcode_subexpr_end:</div><div class="line"><a name="l00262"></a><span class="lineno"> 262</span>  {</div><div class="line"><a name="l00263"></a><span class="lineno"> 263</span>  <span class="keyword">auto</span>& __res = _M_cur_results[__state._M_subexpr];</div><div class="line"><a name="l00264"></a><span class="lineno"> 264</span>  <span class="keyword">auto</span> __back = __res;</div><div class="line"><a name="l00265"></a><span class="lineno"> 265</span>  __res.second = _M_current;</div><div class="line"><a name="l00266"></a><span class="lineno"> 266</span>  __res.matched = <span class="keyword">true</span>;</div><div class="line"><a name="l00267"></a><span class="lineno"> 267</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00268"></a><span class="lineno"> 268</span>  __res = __back;</div><div class="line"><a name="l00269"></a><span class="lineno"> 269</span>  }</div><div class="line"><a name="l00270"></a><span class="lineno"> 270</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00271"></a><span class="lineno"> 271</span>  <span class="keywordflow">case</span> _S_opcode_line_begin_assertion:</div><div class="line"><a name="l00272"></a><span class="lineno"> 272</span>  <span class="keywordflow">if</span> (_M_at_begin())</div><div class="line"><a name="l00273"></a><span class="lineno"> 273</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00274"></a><span class="lineno"> 274</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00275"></a><span class="lineno"> 275</span>  <span class="keywordflow">case</span> _S_opcode_line_end_assertion:</div><div class="line"><a name="l00276"></a><span class="lineno"> 276</span>  <span class="keywordflow">if</span> (_M_at_end())</div><div class="line"><a name="l00277"></a><span class="lineno"> 277</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00278"></a><span class="lineno"> 278</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00279"></a><span class="lineno"> 279</span>  <span class="keywordflow">case</span> _S_opcode_word_boundary:</div><div class="line"><a name="l00280"></a><span class="lineno"> 280</span>  <span class="keywordflow">if</span> (_M_word_boundary() == !__state._M_neg)</div><div class="line"><a name="l00281"></a><span class="lineno"> 281</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00282"></a><span class="lineno"> 282</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00283"></a><span class="lineno"> 283</span>  <span class="comment">// Here __state._M_alt offers a single start node for a sub-NFA.</span></div><div class="line"><a name="l00284"></a><span class="lineno"> 284</span>  <span class="comment">// We recursively invoke our algorithm to match the sub-NFA.</span></div><div class="line"><a name="l00285"></a><span class="lineno"> 285</span>  <span class="keywordflow">case</span> _S_opcode_subexpr_lookahead:</div><div class="line"><a name="l00286"></a><span class="lineno"> 286</span>  <span class="keywordflow">if</span> (_M_lookahead(__state) == !__state._M_neg)</div><div class="line"><a name="l00287"></a><span class="lineno"> 287</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00288"></a><span class="lineno"> 288</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00289"></a><span class="lineno"> 289</span>  <span class="keywordflow">case</span> _S_opcode_match:</div><div class="line"><a name="l00290"></a><span class="lineno"> 290</span>  <span class="keywordflow">if</span> (_M_current == _M_end)</div><div class="line"><a name="l00291"></a><span class="lineno"> 291</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00292"></a><span class="lineno"> 292</span>  <span class="keywordflow">if</span> (__dfs_mode)</div><div class="line"><a name="l00293"></a><span class="lineno"> 293</span>  {</div><div class="line"><a name="l00294"></a><span class="lineno"> 294</span>  <span class="keywordflow">if</span> (__state._M_matches(*_M_current))</div><div class="line"><a name="l00295"></a><span class="lineno"> 295</span>  {</div><div class="line"><a name="l00296"></a><span class="lineno"> 296</span>  ++_M_current;</div><div class="line"><a name="l00297"></a><span class="lineno"> 297</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00298"></a><span class="lineno"> 298</span>  --_M_current;</div><div class="line"><a name="l00299"></a><span class="lineno"> 299</span>  }</div><div class="line"><a name="l00300"></a><span class="lineno"> 300</span>  }</div><div class="line"><a name="l00301"></a><span class="lineno"> 301</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00302"></a><span class="lineno"> 302</span>  <span class="keywordflow">if</span> (__state._M_matches(*_M_current))</div><div class="line"><a name="l00303"></a><span class="lineno"> 303</span>  _M_states._M_queue(__state._M_next, _M_cur_results);</div><div class="line"><a name="l00304"></a><span class="lineno"> 304</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00305"></a><span class="lineno"> 305</span>  <span class="comment">// First fetch the matched result from _M_cur_results as __submatch;</span></div><div class="line"><a name="l00306"></a><span class="lineno"> 306</span>  <span class="comment">// then compare it with</span></div><div class="line"><a name="l00307"></a><span class="lineno"> 307</span>  <span class="comment">// (_M_current, _M_current + (__submatch.second - __submatch.first)).</span></div><div class="line"><a name="l00308"></a><span class="lineno"> 308</span>  <span class="comment">// If matched, keep going; else just return and try another state.</span></div><div class="line"><a name="l00309"></a><span class="lineno"> 309</span>  <span class="keywordflow">case</span> _S_opcode_backref:</div><div class="line"><a name="l00310"></a><span class="lineno"> 310</span>  {</div><div class="line"><a name="l00311"></a><span class="lineno"> 311</span>  _GLIBCXX_DEBUG_ASSERT(__dfs_mode);</div><div class="line"><a name="l00312"></a><span class="lineno"> 312</span>  <span class="keyword">auto</span>& __submatch = _M_cur_results[__state._M_backref_index];</div><div class="line"><a name="l00313"></a><span class="lineno"> 313</span>  <span class="keywordflow">if</span> (!__submatch.matched)</div><div class="line"><a name="l00314"></a><span class="lineno"> 314</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00315"></a><span class="lineno"> 315</span>  <span class="keyword">auto</span> __last = _M_current;</div><div class="line"><a name="l00316"></a><span class="lineno"> 316</span>  <span class="keywordflow">for</span> (<span class="keyword">auto</span> __tmp = __submatch.first;</div><div class="line"><a name="l00317"></a><span class="lineno"> 317</span>  __last != _M_end && __tmp != __submatch.second;</div><div class="line"><a name="l00318"></a><span class="lineno"> 318</span>  ++__tmp)</div><div class="line"><a name="l00319"></a><span class="lineno"> 319</span>  ++__last;</div><div class="line"><a name="l00320"></a><span class="lineno"> 320</span>  <span class="keywordflow">if</span> (_M_re._M_automaton->_M_traits.transform(__submatch.first,</div><div class="line"><a name="l00321"></a><span class="lineno"> 321</span>  __submatch.second)</div><div class="line"><a name="l00322"></a><span class="lineno"> 322</span>  == _M_re._M_automaton->_M_traits.transform(_M_current, __last))</div><div class="line"><a name="l00323"></a><span class="lineno"> 323</span>  {</div><div class="line"><a name="l00324"></a><span class="lineno"> 324</span>  <span class="keywordflow">if</span> (__last != _M_current)</div><div class="line"><a name="l00325"></a><span class="lineno"> 325</span>  {</div><div class="line"><a name="l00326"></a><span class="lineno"> 326</span>  <span class="keyword">auto</span> __backup = _M_current;</div><div class="line"><a name="l00327"></a><span class="lineno"> 327</span>  _M_current = __last;</div><div class="line"><a name="l00328"></a><span class="lineno"> 328</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00329"></a><span class="lineno"> 329</span>  _M_current = __backup;</div><div class="line"><a name="l00330"></a><span class="lineno"> 330</span>  }</div><div class="line"><a name="l00331"></a><span class="lineno"> 331</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00332"></a><span class="lineno"> 332</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00333"></a><span class="lineno"> 333</span>  }</div><div class="line"><a name="l00334"></a><span class="lineno"> 334</span>  }</div><div class="line"><a name="l00335"></a><span class="lineno"> 335</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00336"></a><span class="lineno"> 336</span>  <span class="keywordflow">case</span> _S_opcode_accept:</div><div class="line"><a name="l00337"></a><span class="lineno"> 337</span>  <span class="keywordflow">if</span> (__dfs_mode)</div><div class="line"><a name="l00338"></a><span class="lineno"> 338</span>  {</div><div class="line"><a name="l00339"></a><span class="lineno"> 339</span>  _GLIBCXX_DEBUG_ASSERT(!_M_has_sol);</div><div class="line"><a name="l00340"></a><span class="lineno"> 340</span>  <span class="keywordflow">if</span> (__match_mode == _Match_mode::_Exact)</div><div class="line"><a name="l00341"></a><span class="lineno"> 341</span>  _M_has_sol = _M_current == _M_end;</div><div class="line"><a name="l00342"></a><span class="lineno"> 342</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00343"></a><span class="lineno"> 343</span>  _M_has_sol = <span class="keyword">true</span>;</div><div class="line"><a name="l00344"></a><span class="lineno"> 344</span>  <span class="keywordflow">if</span> (_M_current == _M_begin</div><div class="line"><a name="l00345"></a><span class="lineno"> 345</span>  && (_M_flags & <a class="code" href="a01511.html#af6753cbcbf0322f1cdf7fa2adf6ab75e">regex_constants::match_not_null</a>))</div><div class="line"><a name="l00346"></a><span class="lineno"> 346</span>  _M_has_sol = <span class="keyword">false</span>;</div><div class="line"><a name="l00347"></a><span class="lineno"> 347</span>  <span class="keywordflow">if</span> (_M_has_sol)</div><div class="line"><a name="l00348"></a><span class="lineno"> 348</span>  {</div><div class="line"><a name="l00349"></a><span class="lineno"> 349</span>  <span class="keywordflow">if</span> (_M_nfa._M_flags & <a class="code" href="a01511.html#a44c0e825f131209047520d6951379593">regex_constants::ECMAScript</a>)</div><div class="line"><a name="l00350"></a><span class="lineno"> 350</span>  _M_results = _M_cur_results;</div><div class="line"><a name="l00351"></a><span class="lineno"> 351</span>  <span class="keywordflow">else</span> <span class="comment">// POSIX</span></div><div class="line"><a name="l00352"></a><span class="lineno"> 352</span>  {</div><div class="line"><a name="l00353"></a><span class="lineno"> 353</span>  _GLIBCXX_DEBUG_ASSERT(_M_states._M_get_sol_pos());</div><div class="line"><a name="l00354"></a><span class="lineno"> 354</span>  <span class="comment">// Here's POSIX's logic: match the longest one. However</span></div><div class="line"><a name="l00355"></a><span class="lineno"> 355</span>  <span class="comment">// we never know which one (lhs or rhs of "|") is longer</span></div><div class="line"><a name="l00356"></a><span class="lineno"> 356</span>  <span class="comment">// unless we try both of them and compare the results.</span></div><div class="line"><a name="l00357"></a><span class="lineno"> 357</span>  <span class="comment">// The member variable _M_sol_pos records the end</span></div><div class="line"><a name="l00358"></a><span class="lineno"> 358</span>  <span class="comment">// position of the last successful match. It's better</span></div><div class="line"><a name="l00359"></a><span class="lineno"> 359</span>  <span class="comment">// to be larger, because POSIX regex is always greedy.</span></div><div class="line"><a name="l00360"></a><span class="lineno"> 360</span>  <span class="comment">// TODO: This could be slow.</span></div><div class="line"><a name="l00361"></a><span class="lineno"> 361</span>  <span class="keywordflow">if</span> (*_M_states._M_get_sol_pos() == _BiIter()</div><div class="line"><a name="l00362"></a><span class="lineno"> 362</span>  || <a class="code" href="a01487.html#a5852ded2c7147a161b33951ef37ecba8">std::distance</a>(_M_begin,</div><div class="line"><a name="l00363"></a><span class="lineno"> 363</span>  *_M_states._M_get_sol_pos())</div><div class="line"><a name="l00364"></a><span class="lineno"> 364</span>  < <a class="code" href="a01487.html#a5852ded2c7147a161b33951ef37ecba8">std::distance</a>(_M_begin, _M_current))</div><div class="line"><a name="l00365"></a><span class="lineno"> 365</span>  {</div><div class="line"><a name="l00366"></a><span class="lineno"> 366</span>  *_M_states._M_get_sol_pos() = _M_current;</div><div class="line"><a name="l00367"></a><span class="lineno"> 367</span>  _M_results = _M_cur_results;</div><div class="line"><a name="l00368"></a><span class="lineno"> 368</span>  }</div><div class="line"><a name="l00369"></a><span class="lineno"> 369</span>  }</div><div class="line"><a name="l00370"></a><span class="lineno"> 370</span>  }</div><div class="line"><a name="l00371"></a><span class="lineno"> 371</span>  }</div><div class="line"><a name="l00372"></a><span class="lineno"> 372</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00373"></a><span class="lineno"> 373</span>  {</div><div class="line"><a name="l00374"></a><span class="lineno"> 374</span>  <span class="keywordflow">if</span> (_M_current == _M_begin</div><div class="line"><a name="l00375"></a><span class="lineno"> 375</span>  && (_M_flags & regex_constants::match_not_null))</div><div class="line"><a name="l00376"></a><span class="lineno"> 376</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00377"></a><span class="lineno"> 377</span>  <span class="keywordflow">if</span> (__match_mode == _Match_mode::_Prefix || _M_current == _M_end)</div><div class="line"><a name="l00378"></a><span class="lineno"> 378</span>  <span class="keywordflow">if</span> (!_M_has_sol)</div><div class="line"><a name="l00379"></a><span class="lineno"> 379</span>  {</div><div class="line"><a name="l00380"></a><span class="lineno"> 380</span>  _M_has_sol = <span class="keyword">true</span>;</div><div class="line"><a name="l00381"></a><span class="lineno"> 381</span>  _M_results = _M_cur_results;</div><div class="line"><a name="l00382"></a><span class="lineno"> 382</span>  }</div><div class="line"><a name="l00383"></a><span class="lineno"> 383</span>  }</div><div class="line"><a name="l00384"></a><span class="lineno"> 384</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00385"></a><span class="lineno"> 385</span>  <span class="keywordflow">case</span> _S_opcode_alternative:</div><div class="line"><a name="l00386"></a><span class="lineno"> 386</span>  <span class="keywordflow">if</span> (_M_nfa._M_flags & <a class="code" href="a01511.html#a44c0e825f131209047520d6951379593">regex_constants::ECMAScript</a>)</div><div class="line"><a name="l00387"></a><span class="lineno"> 387</span>  {</div><div class="line"><a name="l00388"></a><span class="lineno"> 388</span>  <span class="comment">// TODO: Let BFS support ECMAScript's alternative operation.</span></div><div class="line"><a name="l00389"></a><span class="lineno"> 389</span>  _GLIBCXX_DEBUG_ASSERT(__dfs_mode);</div><div class="line"><a name="l00390"></a><span class="lineno"> 390</span>  _M_dfs(__match_mode, __state._M_alt);</div><div class="line"><a name="l00391"></a><span class="lineno"> 391</span>  <span class="comment">// Pick lhs if it matches. Only try rhs if it doesn't.</span></div><div class="line"><a name="l00392"></a><span class="lineno"> 392</span>  <span class="keywordflow">if</span> (!_M_has_sol)</div><div class="line"><a name="l00393"></a><span class="lineno"> 393</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00394"></a><span class="lineno"> 394</span>  }</div><div class="line"><a name="l00395"></a><span class="lineno"> 395</span>  <span class="keywordflow">else</span></div><div class="line"><a name="l00396"></a><span class="lineno"> 396</span>  {</div><div class="line"><a name="l00397"></a><span class="lineno"> 397</span>  <span class="comment">// Try both and compare the result.</span></div><div class="line"><a name="l00398"></a><span class="lineno"> 398</span>  <span class="comment">// See "case _S_opcode_accept:" handling above.</span></div><div class="line"><a name="l00399"></a><span class="lineno"> 399</span>  _M_dfs(__match_mode, __state._M_alt);</div><div class="line"><a name="l00400"></a><span class="lineno"> 400</span>  <span class="keyword">auto</span> __has_sol = _M_has_sol;</div><div class="line"><a name="l00401"></a><span class="lineno"> 401</span>  _M_has_sol = <span class="keyword">false</span>;</div><div class="line"><a name="l00402"></a><span class="lineno"> 402</span>  _M_dfs(__match_mode, __state._M_next);</div><div class="line"><a name="l00403"></a><span class="lineno"> 403</span>  _M_has_sol |= __has_sol;</div><div class="line"><a name="l00404"></a><span class="lineno"> 404</span>  }</div><div class="line"><a name="l00405"></a><span class="lineno"> 405</span>  <span class="keywordflow">break</span>;</div><div class="line"><a name="l00406"></a><span class="lineno"> 406</span>  <span class="keywordflow">default</span>:</div><div class="line"><a name="l00407"></a><span class="lineno"> 407</span>  _GLIBCXX_DEBUG_ASSERT(<span class="keyword">false</span>);</div><div class="line"><a name="l00408"></a><span class="lineno"> 408</span>  }</div><div class="line"><a name="l00409"></a><span class="lineno"> 409</span>  }</div><div class="line"><a name="l00410"></a><span class="lineno"> 410</span> </div><div class="line"><a name="l00411"></a><span class="lineno"> 411</span>  <span class="comment">// Return whether now is at some word boundary.</span></div><div class="line"><a name="l00412"></a><span class="lineno"> 412</span>  <span class="keyword">template</span><<span class="keyword">typename</span> _BiIter, <span class="keyword">typename</span> _Alloc, <span class="keyword">typename</span> _TraitsT,</div><div class="line"><a name="l00413"></a><span class="lineno"> 413</span>  <span class="keywordtype">bool</span> __dfs_mode></div><div class="line"><a name="l00414"></a><span class="lineno"> 414</span>  <span class="keywordtype">bool</span> _Executor<_BiIter, _Alloc, _TraitsT, __dfs_mode>::</div><div class="line"><a name="l00415"></a><span class="lineno"> 415</span>  _M_word_boundary()<span class="keyword"> const</span></div><div class="line"><a name="l00416"></a><span class="lineno"> 416</span> <span class="keyword"> </span>{</div><div class="line"><a name="l00417"></a><span class="lineno"> 417</span>  <span class="keywordtype">bool</span> __left_is_word = <span class="keyword">false</span>;</div><div class="line"><a name="l00418"></a><span class="lineno"> 418</span>  <span class="keywordflow">if</span> (_M_current != _M_begin</div><div class="line"><a name="l00419"></a><span class="lineno"> 419</span>  || (_M_flags & <a class="code" href="a01511.html#ad730b04e961da111de1dc350953f48ba">regex_constants::match_prev_avail</a>))</div><div class="line"><a name="l00420"></a><span class="lineno"> 420</span>  {</div><div class="line"><a name="l00421"></a><span class="lineno"> 421</span>  <span class="keyword">auto</span> __prev = _M_current;</div><div class="line"><a name="l00422"></a><span class="lineno"> 422</span>  <span class="keywordflow">if</span> (_M_is_word(*std::prev(__prev)))</div><div class="line"><a name="l00423"></a><span class="lineno"> 423</span>  __left_is_word = <span class="keyword">true</span>;</div><div class="line"><a name="l00424"></a><span class="lineno"> 424</span>  }</div><div class="line"><a name="l00425"></a><span class="lineno"> 425</span>  <span class="keywordtype">bool</span> __right_is_word =</div><div class="line"><a name="l00426"></a><span class="lineno"> 426</span>  _M_current != _M_end && _M_is_word(*_M_current);</div><div class="line"><a name="l00427"></a><span class="lineno"> 427</span> </div><div class="line"><a name="l00428"></a><span class="lineno"> 428</span>  <span class="keywordflow">if</span> (__left_is_word == __right_is_word)</div><div class="line"><a name="l00429"></a><span class="lineno"> 429</span>  <span class="keywordflow">return</span> <span class="keyword">false</span>;</div><div class="line"><a name="l00430"></a><span class="lineno"> 430</span>  <span class="keywordflow">if</span> (__left_is_word && !(_M_flags & <a class="code" href="a01511.html#af23b92e4bceadee2beb477ddbe79111d">regex_constants::match_not_eow</a>))</div><div class="line"><a name="l00431"></a><span class="lineno"> 431</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div><div class="line"><a name="l00432"></a><span class="lineno"> 432</span>  <span class="keywordflow">if</span> (__right_is_word && !(_M_flags & <a class="code" href="a01511.html#a3f995fe4c885c05599fe0495f659d253">regex_constants::match_not_bow</a>))</div><div class="line"><a name="l00433"></a><span class="lineno"> 433</span>  <span class="keywordflow">return</span> <span class="keyword">true</span>;</div><div class="line"><a name="l00434"></a><span class="lineno"> 434</span>  <span class="keywordflow">return</span> <span class="keyword">false</span>;</div><div class="line"><a name="l00435"></a><span class="lineno"> 435</span>  }</div><div class="line"><a name="l00436"></a><span class="lineno"> 436</span> </div><div class="line"><a name="l00437"></a><span class="lineno"> 437</span> _GLIBCXX_END_NAMESPACE_VERSION</div><div class="line"><a name="l00438"></a><span class="lineno"> 438</span> } <span class="comment">// namespace __detail</span></div><div class="line"><a name="l00439"></a><span class="lineno"> 439</span> } <span class="comment">// namespace</span></div><div class="ttc" id="a01487_html_a5852ded2c7147a161b33951ef37ecba8"><div class="ttname"><a href="a01487.html#a5852ded2c7147a161b33951ef37ecba8">std::distance</a></div><div class="ttdeci">iterator_traits< _InputIterator >::difference_type distance(_InputIterator __first, _InputIterator __last)</div><div class="ttdoc">A generalization of pointer arithmetic. </div><div class="ttdef"><b>Definition:</b> <a href="a00506_source.html#l00114">stl_iterator_base_funcs.h:114</a></div></div> <div class="ttc" id="a01511_html_af23b92e4bceadee2beb477ddbe79111d"><div class="ttname"><a href="a01511.html#af23b92e4bceadee2beb477ddbe79111d">std::regex_constants::match_not_eow</a></div><div class="ttdeci">constexpr match_flag_type match_not_eow</div><div class="ttdef"><b>Definition:</b> <a href="a00449_source.html#l00279">regex_constants.h:279</a></div></div> <div class="ttc" id="a01511_html_a44c0e825f131209047520d6951379593"><div class="ttname"><a href="a01511.html#a44c0e825f131209047520d6951379593">std::regex_constants::ECMAScript</a></div><div class="ttdeci">constexpr syntax_option_type ECMAScript</div><div class="ttdef"><b>Definition:</b> <a href="a00449_source.html#l00121">regex_constants.h:121</a></div></div> <div class="ttc" id="a01511_html_af6753cbcbf0322f1cdf7fa2adf6ab75e"><div class="ttname"><a href="a01511.html#af6753cbcbf0322f1cdf7fa2adf6ab75e">std::regex_constants::match_not_null</a></div><div class="ttdeci">constexpr match_flag_type match_not_null</div><div class="ttdef"><b>Definition:</b> <a href="a00449_source.html#l00292">regex_constants.h:292</a></div></div> <div class="ttc" id="a01511_html_ad730b04e961da111de1dc350953f48ba"><div class="ttname"><a href="a01511.html#ad730b04e961da111de1dc350953f48ba">std::regex_constants::match_prev_avail</a></div><div class="ttdeci">constexpr match_flag_type match_prev_avail</div><div class="ttdef"><b>Definition:</b> <a href="a00449_source.html#l00306">regex_constants.h:306</a></div></div> <div class="ttc" id="a01511_html_a3f995fe4c885c05599fe0495f659d253"><div class="ttname"><a href="a01511.html#a3f995fe4c885c05599fe0495f659d253">std::regex_constants::match_not_bow</a></div><div class="ttdeci">constexpr match_flag_type match_not_bow</div><div class="ttdef"><b>Definition:</b> <a href="a00449_source.html#l00272">regex_constants.h:272</a></div></div> <div class="ttc" id="a01487_html"><div class="ttname"><a href="a01487.html">std</a></div><div class="ttdoc">ISO C++ entities toplevel namespace is std. </div></div> <div class="ttc" id="a01511_html_a905d343797be96365d8d663cfc7411f2"><div class="ttname"><a href="a01511.html#a905d343797be96365d8d663cfc7411f2">std::regex_constants::match_continuous</a></div><div class="ttdeci">constexpr match_flag_type match_continuous</div><div class="ttdef"><b>Definition:</b> <a href="a00449_source.html#l00298">regex_constants.h:298</a></div></div> <div class="ttc" id="a01434_html_ga0af400b776b8486401daf6ecf91bacca"><div class="ttname"><a href="a01434.html#ga0af400b776b8486401daf6ecf91bacca">std::fill_n</a></div><div class="ttdeci">_OI fill_n(_OI __first, _Size __n, const _Tp &__value)</div><div class="ttdoc">Fills the range [first,first+n) with copies of value. </div><div class="ttdef"><b>Definition:</b> <a href="a00485_source.html#l00800">stl_algobase.h:800</a></div></div> </div><!-- fragment --></div><!-- contents --> </div><!-- doc-content --> <!-- start footer part --> <div id="nav-path" class="navpath"><!-- id is needed for treeview function! --> <ul> <li class="navelem"><a 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