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         ostr << "alt next=" << _M_next << " alt=" << _M_alt;
  45         break;
  46       case _S_opcode_subexpr_begin:
  47         ostr << "subexpr begin next=" << _M_next << " index=" << _M_subexpr;
  48         break;
  49       case _S_opcode_subexpr_end:
  50         ostr << "subexpr end next=" << _M_next << " index=" << _M_subexpr;
  51         break;
  52       case _S_opcode_backref:
  53         ostr << "backref next=" << _M_next << " index=" << _M_backref_index;
  54         break;
  55       case _S_opcode_match:
  56         ostr << "match next=" << _M_next;
  57         break;
  58       case _S_opcode_accept:
  59         ostr << "accept next=" << _M_next;
  60         break;
  61       default:
  62         ostr << "unknown next=" << _M_next;
  63         break;
  64     }
  65     return ostr;
  66   }
  67
  68   // Prints graphviz dot commands for state.
  69   std::ostream&
  70   _State_base::_M_dot(std::ostream& __ostr, _StateIdT __id) const
  71   {
  72     switch (_M_opcode)
  73     {
  74       case _S_opcode_alternative:
  75         __ostr << __id << " [label=\"" << __id << "\\nALT\"];\n"
  76                << __id << " -> " << _M_next
  77                << " [label=\"epsilon\", tailport=\"s\"];\n"
  78                << __id << " -> " << _M_alt
  79                << " [label=\"epsilon\", tailport=\"n\"];\n";
  80         break;
  81       case _S_opcode_backref:
  82         __ostr << __id << " [label=\"" << __id << "\\nBACKREF "
  83                << _M_subexpr << "\"];\n"
  84                << __id << " -> " << _M_next << " [label=\"<match>\"];\n";
  85         break;
  86       case _S_opcode_line_begin_assertion:
  87         __ostr << __id << " [label=\"" << __id << "\\nLINE_BEGIN \"];\n"
  88                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
  89         break;
  90       case _S_opcode_line_end_assertion:
  91         __ostr << __id << " [label=\"" << __id << "\\nLINE_END \"];\n"
  92                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
  93         break;
  94       case _S_opcode_word_boundary:
  95         __ostr << __id << " [label=\"" << __id << "\\nWORD_BOUNDRY "
  96                << _M_neg << "\"];\n"
  97                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
  98         break;
  99       case _S_opcode_subexpr_lookahead:
 100         __ostr << __id << " [label=\"" << __id << "\\nLOOK_AHEAD\"];\n"
 101                << __id << " -> " << _M_next
 102                << " [label=\"epsilon\", tailport=\"s\"];\n"
 103                << __id << " -> " << _M_alt
 104                << " [label=\"<assert>\", tailport=\"n\"];\n";
 105         break;
 106       case _S_opcode_subexpr_begin:
 107         __ostr << __id << " [label=\"" << __id << "\\nSBEGIN "
 108                << _M_subexpr << "\"];\n"
 109                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
 110         break;
 111       case _S_opcode_subexpr_end:
 112         __ostr << __id << " [label=\"" << __id << "\\nSEND "
 113                << _M_subexpr << "\"];\n"
 114                << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
 115         break;
 116       case _S_opcode_dummy:
 117         break;
 118       case _S_opcode_match:
 119         __ostr << __id << " [label=\"" << __id << "\\nMATCH\"];\n"
 120                << __id << " -> " << _M_next << " [label=\"<match>\"];\n";
 121         break;
 122       case _S_opcode_accept:
 123         __ostr << __id << " [label=\"" << __id << "\\nACC\"];\n" ;
 124         break;
 125       default:
 126         _GLIBCXX_DEBUG_ASSERT(false);
 127         break;
 128     }
 129     return __ostr;
 130   }
 131
 132   template<typename _TraitsT>
 133     std::ostream&
 134     _NFA<_TraitsT>::_M_dot(std::ostream& __ostr) const
 135     {
 136       __ostr << "digraph _Nfa {\n"
 137                 "  rankdir=LR;\n";
 138       for (size_t __i = 0; __i < this->size(); ++__i)
 139         (*this)[__i]._M_dot(__ostr, __i);
 140       __ostr << "}\n";
 141       return __ostr;
 142     }
 143 #endif
 144
 145   template<typename _TraitsT>
 146     _StateIdT
 147     _NFA<_TraitsT>::_M_insert_backref(size_t __index)
 148     {
 149       // To figure out whether a backref is valid, a stack is used to store
 150       // unfinished sub-expressions. For example, when parsing
 151       // "(a(b)(c\\1(d)))" at '\\1', _M_subexpr_count is 3, indicating that 3
 152       // sub expressions are parsed or partially parsed(in the stack), aka,
 153       // "(a..", "(b)" and "(c..").
 154       // _M_paren_stack is {1, 3}, for incomplete "(a.." and "(c..". At this
 155       // time, "\\2" is valid, but "\\1" and "\\3" are not.
 156       if (__index >= _M_subexpr_count)
 157         __throw_regex_error(regex_constants::error_backref);
 158       for (auto __it : this->_M_paren_stack)
 159         if (__index == __it)
 160           __throw_regex_error(regex_constants::error_backref);
 161       this->_M_has_backref = true;
 162       _StateT __tmp(_S_opcode_backref);
 163       __tmp._M_backref_index = __index;
 164       return _M_insert_state(std::move(__tmp));
 165     }
 166
 167   template<typename _TraitsT>
 168     void
 169     _NFA<_TraitsT>::_M_eliminate_dummy()
 170     {
 171       for (auto& __it : *this)
 172         {
 173           while (__it._M_next >= 0 && (*this)[__it._M_next]._M_opcode
 174                  == _S_opcode_dummy)
 175             __it._M_next = (*this)[__it._M_next]._M_next;
 176           if (__it._M_opcode == _S_opcode_alternative
 177               || __it._M_opcode == _S_opcode_subexpr_lookahead)
 178             while (__it._M_alt >= 0 && (*this)[__it._M_alt]._M_opcode
 179                    == _S_opcode_dummy)
 180               __it._M_alt = (*this)[__it._M_alt]._M_next;
 181         }
 182     }
 183
 184   // Just apply DFS on the sequence and re-link their links.
 185   template<typename _TraitsT>
 186     _StateSeq<_TraitsT>
 187     _StateSeq<_TraitsT>::_M_clone()
 188     {
 189       std::vector<_StateIdT> __m(_M_nfa.size(), -1);
 190       std::stack<_StateIdT> __stack;
 191       __stack.push(_M_start);
 192       while (!__stack.empty())
 193         {
 194           auto __u = __stack.top();
 195           __stack.pop();
 196           auto __dup = _M_nfa[__u];
 197           // _M_insert_state() never return -1
 198           auto __id = _M_nfa._M_insert_state(__dup);
 199           __m[__u] = __id;
 200           if (__dup._M_opcode == _S_opcode_alternative
 201               || __dup._M_opcode == _S_opcode_subexpr_lookahead)
 202             if (__dup._M_alt != _S_invalid_state_id && __m[__dup._M_alt] == -1)
 203               __stack.push(__dup._M_alt);
 204           if (__u == _M_end)
 205             continue;
 206           if (__dup._M_next != _S_invalid_state_id && __m[__dup._M_next] == -1)
 207             __stack.push(__dup._M_next);
 208         }
 209       for (auto __v : __m)
 210         {
 211           if (__v == -1)
 212             continue;
 213           auto& __ref = _M_nfa[__v];
 214           if (__ref._M_next != _S_invalid_state_id)
 215             {
 216               _GLIBCXX_DEBUG_ASSERT(__m[__ref._M_next] != -1);
 217               __ref._M_next = __m[__ref._M_next];
 218             }
 219           if (__ref._M_opcode == _S_opcode_alternative
 220               || __ref._M_opcode == _S_opcode_subexpr_lookahead)
 221             if (__ref._M_alt != _S_invalid_state_id)
 222               {
 223                 _GLIBCXX_DEBUG_ASSERT(__m[__ref._M_alt] != -1);
 224                 __ref._M_alt = __m[__ref._M_alt];
 225               }
 226         }
 227       return _StateSeq(_M_nfa, __m[_M_start], __m[_M_end]);
 228     }
 229
 230 _GLIBCXX_END_NAMESPACE_VERSION
 231 } // namespace __detail
 232 } // namespace