libstdc++-v3/include/bits/regex_automaton.tcc

   1 // class template regex -*- C++ -*-
   2
   3 // Copyright (C) 2013-2014 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 3, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // Under Section 7 of GPL version 3, you are granted additional
  17 // permissions described in the GCC Runtime Library Exception, version
  18 // 3.1, as published by the Free Software Foundation.
  19
  20 // You should have received a copy of the GNU General Public License and
  21 // a copy of the GCC Runtime Library Exception along with this program;
  22 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 // <http://www.gnu.org/licenses/>.
  24
  25 /**
  26  *  @file bits/regex_automaton.tcc
  27  *  This is an internal header file, included by other library headers.
  28  *  Do not attempt to use it directly. @headername{regex}
  29  */
  30
  31 namespace std _GLIBCXX_VISIBILITY(default)
  32 {
  33 namespace __detail
  34 {
  35 _GLIBCXX_BEGIN_NAMESPACE_VERSION
  36
  37 #ifdef _GLIBCXX_DEBUG
  38   std::ostream&
  39   _State_base::_M_print(std::ostream& ostr) const
  40   {
  41     switch (_M_opcode)
  42     {
  43       case _S_opcode_alternative:
  44       case _S_opcode_repeat:
  45         ostr << "alt next=" << _M_next << " alt=" << _M_alt;
  46         break;
  47       case _S_opcode_subexpr_begin:
  48         ostr << "subexpr begin next=" << _M_next << " index=" << _M_subexpr;
  49         break;
  50       case _S_opcode_subexpr_end:
  51         ostr << "subexpr end next=" << _M_next << " index=" << _M_subexpr;
  52         break;
  53       case _S_opcode_backref:
  54         ostr << "backref next=" << _M_next << " index=" << _M_backref_index;
  55         break;
  56       case _S_opcode_match:
  57         ostr << "match next=" << _M_next;
  58         break;
  59       case _S_opcode_accept:
  60         ostr << "accept next=" << _M_next;
  61         break;
  62       default:
  63         ostr << "unknown next=" << _M_next;
  64         break;
  65     }
  66     return ostr;
  67   }
  68
  69   // Prints graphviz dot commands for state.
  70   std::ostream&
  71   _State_base::_M_dot(std::ostream& __ostr, _StateIdT __id) const
  72   {
  73     switch (_M_opcode)
  74     {
  75       case _S_opcode_alternative:
  76       case _S_opcode_repeat:
  77         __ostr << __id << " [label=\"" << __id << "\\nALT\"];\n"
  78                << __id << " -> " << _M_next
  79                << " [label=\"next\", tailport=\"s\"];\n"
  80                << __id << " -> " << _M_alt
  81                << " [label=\"alt\", tailport=\"n\"];\n";
  82         break;
  83       case _S_opcode_backref:
  84         __ostr << __id << " [label=\"" << __id << "\\nBACKREF "
  85                << _M_subexpr << "\"];\n"
  86                << __id << " -> " << _M_next << " [label=\"<match>\"];\n";
  87         break;
  88       case _S_opcode_line_begin_assertion:
  89         __ostr << __id << " [label=\"" << __id << "\\nLINE_BEGIN \"];\n"
  90                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
  91         break;
  92       case _S_opcode_line_end_assertion:
  93         __ostr << __id << " [label=\"" << __id << "\\nLINE_END \"];\n"
  94                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
  95         break;
  96       case _S_opcode_word_boundary:
  97         __ostr << __id << " [label=\"" << __id << "\\nWORD_BOUNDRY "
  98                << _M_neg << "\"];\n"
  99                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
 100         break;
 101       case _S_opcode_subexpr_lookahead:
 102         __ostr << __id << " [label=\"" << __id << "\\nLOOK_AHEAD\"];\n"
 103                << __id << " -> " << _M_next
 104                << " [label=\"epsilon\", tailport=\"s\"];\n"
 105                << __id << " -> " << _M_alt
 106                << " [label=\"<assert>\", tailport=\"n\"];\n";
 107         break;
 108       case _S_opcode_subexpr_begin:
 109         __ostr << __id << " [label=\"" << __id << "\\nSBEGIN "
 110                << _M_subexpr << "\"];\n"
 111                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
 112         break;
 113       case _S_opcode_subexpr_end:
 114         __ostr << __id << " [label=\"" << __id << "\\nSEND "
 115                << _M_subexpr << "\"];\n"
 116                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
 117         break;
 118       case _S_opcode_dummy:
 119         break;
 120       case _S_opcode_match:
 121         __ostr << __id << " [label=\"" << __id << "\\nMATCH\"];\n"
 122                << __id << " -> " << _M_next << " [label=\"<match>\"];\n";
 123         break;
 124       case _S_opcode_accept:
 125         __ostr << __id << " [label=\"" << __id << "\\nACC\"];\n" ;
 126         break;
 127       default:
 128         _GLIBCXX_DEBUG_ASSERT(false);
 129         break;
 130     }
 131     return __ostr;
 132   }
 133
 134   template<typename _TraitsT>
 135     std::ostream&
 136     _NFA<_TraitsT>::_M_dot(std::ostream& __ostr) const
 137     {
 138       __ostr << "digraph _Nfa {\n"
 139                 "  rankdir=LR;\n";
 140       for (size_t __i = 0; __i < this->size(); ++__i)
 141         (*this)[__i]._M_dot(__ostr, __i);
 142       __ostr << "}\n";
 143       return __ostr;
 144     }
 145 #endif
 146
 147   template<typename _TraitsT>
 148     _StateIdT
 149     _NFA<_TraitsT>::_M_insert_backref(size_t __index)
 150     {
 151       // To figure out whether a backref is valid, a stack is used to store
 152       // unfinished sub-expressions. For example, when parsing
 153       // "(a(b)(c\\1(d)))" at '\\1', _M_subexpr_count is 3, indicating that 3
 154       // sub expressions are parsed or partially parsed(in the stack), aka,
 155       // "(a..", "(b)" and "(c..").
 156       // _M_paren_stack is {1, 3}, for incomplete "(a.." and "(c..". At this
 157       // time, "\\2" is valid, but "\\1" and "\\3" are not.
 158       if (__index >= _M_subexpr_count)
 159         __throw_regex_error(regex_constants::error_backref);
 160       for (auto __it : this->_M_paren_stack)
 161         if (__index == __it)
 162           __throw_regex_error(regex_constants::error_backref);
 163       this->_M_has_backref = true;
 164       _StateT __tmp(_S_opcode_backref);
 165       __tmp._M_backref_index = __index;
 166       return _M_insert_state(std::move(__tmp));
 167     }
 168
 169   template<typename _TraitsT>
 170     void
 171     _NFA<_TraitsT>::_M_eliminate_dummy()
 172     {
 173       for (auto& __it : *this)
 174         {
 175           while (__it._M_next >= 0 && (*this)[__it._M_next]._M_opcode
 176                  == _S_opcode_dummy)
 177             __it._M_next = (*this)[__it._M_next]._M_next;
 178           if (__it._M_opcode == _S_opcode_alternative
 179               || __it._M_opcode == _S_opcode_repeat
 180               || __it._M_opcode == _S_opcode_subexpr_lookahead)
 181             while (__it._M_alt >= 0 && (*this)[__it._M_alt]._M_opcode
 182                    == _S_opcode_dummy)
 183               __it._M_alt = (*this)[__it._M_alt]._M_next;
 184         }
 185     }
 186
 187   // Just apply DFS on the sequence and re-link their links.
 188   template<typename _TraitsT>
 189     _StateSeq<_TraitsT>
 190     _StateSeq<_TraitsT>::_M_clone()
 191     {
 192       std::vector<_StateIdT> __m(_M_nfa.size(), -1);
 193       std::stack<_StateIdT> __stack;
 194       __stack.push(_M_start);
 195       while (!__stack.empty())
 196         {
 197           auto __u = __stack.top();
 198           __stack.pop();
 199           auto __dup = _M_nfa[__u];
 200           // _M_insert_state() never return -1
 201           auto __id = _M_nfa._M_insert_state(__dup);
 202           __m[__u] = __id;
 203           if (__dup._M_opcode == _S_opcode_alternative
 204               || __dup._M_opcode == _S_opcode_repeat
 205               || __dup._M_opcode == _S_opcode_subexpr_lookahead)
 206             if (__dup._M_alt != _S_invalid_state_id && __m[__dup._M_alt] == -1)
 207               __stack.push(__dup._M_alt);
 208           if (__u == _M_end)
 209             continue;
 210           if (__dup._M_next != _S_invalid_state_id && __m[__dup._M_next] == -1)
 211             __stack.push(__dup._M_next);
 212         }
 213       for (auto __v : __m)
 214         {
 215           if (__v == -1)
 216             continue;
 217           auto& __ref = _M_nfa[__v];
 218           if (__ref._M_next != _S_invalid_state_id)
 219             {
 220               _GLIBCXX_DEBUG_ASSERT(__m[__ref._M_next] != -1);
 221               __ref._M_next = __m[__ref._M_next];
 222             }
 223           if (__ref._M_opcode == _S_opcode_alternative
 224               || __ref._M_opcode == _S_opcode_repeat
 225               || __ref._M_opcode == _S_opcode_subexpr_lookahead)
 226             if (__ref._M_alt != _S_invalid_state_id)
 227               {
 228                 _GLIBCXX_DEBUG_ASSERT(__m[__ref._M_alt] != -1);
 229                 __ref._M_alt = __m[__ref._M_alt];
 230               }
 231         }
 232       return _StateSeq(_M_nfa, __m[_M_start], __m[_M_end]);
 233     }
 234
 235 _GLIBCXX_END_NAMESPACE_VERSION
 236 } // namespace __detail
 237 } // namespace