libstdc++
regex_automaton.tcc
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00001 // class template regex -*- C++ -*-
00002 
00003 // Copyright (C) 2013-2014 Free Software Foundation, Inc.
00004 //
00005 // This file is part of the GNU ISO C++ Library.  This library is free
00006 // software; you can redistribute it and/or modify it under the
00007 // terms of the GNU General Public License as published by the
00008 // Free Software Foundation; either version 3, or (at your option)
00009 // any later version.
00010 
00011 // This library is distributed in the hope that it will be useful,
00012 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00013 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014 // GNU General Public License for more details.
00015 
00016 // Under Section 7 of GPL version 3, you are granted additional
00017 // permissions described in the GCC Runtime Library Exception, version
00018 // 3.1, as published by the Free Software Foundation.
00019 
00020 // You should have received a copy of the GNU General Public License and
00021 // a copy of the GCC Runtime Library Exception along with this program;
00022 // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
00023 // <http://www.gnu.org/licenses/>.
00024 
00025 /**
00026  *  @file bits/regex_automaton.tcc
00027  *  This is an internal header file, included by other library headers.
00028  *  Do not attempt to use it directly. @headername{regex}
00029  */
00030 
00031 namespace std _GLIBCXX_VISIBILITY(default)
00032 {
00033 namespace __detail
00034 {
00035 _GLIBCXX_BEGIN_NAMESPACE_VERSION
00036 
00037 #ifdef _GLIBCXX_DEBUG
00038   inline std::ostream&
00039   _State_base::_M_print(std::ostream& ostr) const
00040   {
00041     switch (_M_opcode)
00042     {
00043       case _S_opcode_alternative:
00044     ostr << "alt next=" << _M_next << " alt=" << _M_alt;
00045     break;
00046       case _S_opcode_subexpr_begin:
00047     ostr << "subexpr begin next=" << _M_next << " index=" << _M_subexpr;
00048     break;
00049       case _S_opcode_subexpr_end:
00050     ostr << "subexpr end next=" << _M_next << " index=" << _M_subexpr;
00051     break;
00052       case _S_opcode_backref:
00053     ostr << "backref next=" << _M_next << " index=" << _M_backref_index;
00054     break;
00055       case _S_opcode_match:
00056     ostr << "match next=" << _M_next;
00057     break;
00058       case _S_opcode_accept:
00059     ostr << "accept next=" << _M_next;
00060     break;
00061       default:
00062     ostr << "unknown next=" << _M_next;
00063     break;
00064     }
00065     return ostr;
00066   }
00067 
00068   // Prints graphviz dot commands for state.
00069   inline std::ostream&
00070   _State_base::_M_dot(std::ostream& __ostr, _StateIdT __id) const
00071   {
00072     switch (_M_opcode)
00073     {
00074       case _S_opcode_alternative:
00075     __ostr << __id << " [label=\"" << __id << "\\nALT\"];\n"
00076            << __id << " -> " << _M_next
00077            << " [label=\"epsilon\", tailport=\"s\"];\n"
00078            << __id << " -> " << _M_alt
00079            << " [label=\"epsilon\", tailport=\"n\"];\n";
00080     break;
00081       case _S_opcode_backref:
00082     __ostr << __id << " [label=\"" << __id << "\\nBACKREF "
00083            << _M_subexpr << "\"];\n"
00084            << __id << " -> " << _M_next << " [label=\"<match>\"];\n";
00085     break;
00086       case _S_opcode_line_begin_assertion:
00087     __ostr << __id << " [label=\"" << __id << "\\nLINE_BEGIN \"];\n"
00088            << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
00089     break;
00090       case _S_opcode_line_end_assertion:
00091     __ostr << __id << " [label=\"" << __id << "\\nLINE_END \"];\n"
00092            << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
00093     break;
00094       case _S_opcode_word_boundary:
00095     __ostr << __id << " [label=\"" << __id << "\\nWORD_BOUNDRY "
00096            << _M_neg << "\"];\n"
00097            << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
00098     break;
00099       case _S_opcode_subexpr_lookahead:
00100     __ostr << __id << " [label=\"" << __id << "\\nLOOK_AHEAD\"];\n"
00101            << __id << " -> " << _M_next
00102            << " [label=\"epsilon\", tailport=\"s\"];\n"
00103            << __id << " -> " << _M_alt
00104            << " [label=\"<assert>\", tailport=\"n\"];\n";
00105     break;
00106       case _S_opcode_subexpr_begin:
00107     __ostr << __id << " [label=\"" << __id << "\\nSBEGIN "
00108            << _M_subexpr << "\"];\n"
00109            << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
00110     break;
00111       case _S_opcode_subexpr_end:
00112     __ostr << __id << " [label=\"" << __id << "\\nSEND "
00113            << _M_subexpr << "\"];\n"
00114            << __id << " -> " << _M_next << " [label=\"epsilon\"];\n";
00115     break;
00116       case _S_opcode_dummy:
00117     break;
00118       case _S_opcode_match:
00119     __ostr << __id << " [label=\"" << __id << "\\nMATCH\"];\n"
00120            << __id << " -> " << _M_next << " [label=\"<match>\"];\n";
00121     break;
00122       case _S_opcode_accept:
00123     __ostr << __id << " [label=\"" << __id << "\\nACC\"];\n" ;
00124     break;
00125       default:
00126     _GLIBCXX_DEBUG_ASSERT(false);
00127     break;
00128     }
00129     return __ostr;
00130   }
00131 
00132   template<typename _TraitsT>
00133     std::ostream&
00134     _NFA<_TraitsT>::_M_dot(std::ostream& __ostr) const
00135     {
00136       __ostr << "digraph _Nfa {\n"
00137         "  rankdir=LR;\n";
00138       for (size_t __i = 0; __i < this->size(); ++__i)
00139     (*this)[__i]._M_dot(__ostr, __i);
00140       __ostr << "}\n";
00141       return __ostr;
00142     }
00143 #endif
00144 
00145   template<typename _TraitsT>
00146     _StateIdT
00147     _NFA<_TraitsT>::_M_insert_backref(size_t __index)
00148     {
00149       // To figure out whether a backref is valid, a stack is used to store
00150       // unfinished sub-expressions. For example, when parsing
00151       // "(a(b)(c\\1(d)))" at '\\1', _M_subexpr_count is 3, indicating that 3
00152       // sub expressions are parsed or partially parsed(in the stack), aka,
00153       // "(a..", "(b)" and "(c..").
00154       // _M_paren_stack is {1, 3}, for incomplete "(a.." and "(c..". At this
00155       // time, "\\2" is valid, but "\\1" and "\\3" are not.
00156       if (__index >= _M_subexpr_count)
00157     __throw_regex_error(regex_constants::error_backref);
00158       for (auto __it : this->_M_paren_stack)
00159     if (__index == __it)
00160       __throw_regex_error(regex_constants::error_backref);
00161       this->_M_has_backref = true;
00162       _StateT __tmp(_S_opcode_backref);
00163       __tmp._M_backref_index = __index;
00164       return _M_insert_state(std::move(__tmp));
00165     }
00166 
00167   template<typename _TraitsT>
00168     void
00169     _NFA<_TraitsT>::_M_eliminate_dummy()
00170     {
00171       for (auto& __it : *this)
00172     {
00173       while (__it._M_next >= 0 && (*this)[__it._M_next]._M_opcode
00174          == _S_opcode_dummy)
00175         __it._M_next = (*this)[__it._M_next]._M_next;
00176       if (__it._M_opcode == _S_opcode_alternative
00177           || __it._M_opcode == _S_opcode_subexpr_lookahead)
00178         while (__it._M_alt >= 0 && (*this)[__it._M_alt]._M_opcode
00179            == _S_opcode_dummy)
00180           __it._M_alt = (*this)[__it._M_alt]._M_next;
00181     }
00182     }
00183 
00184   // Just apply DFS on the sequence and re-link their links.
00185   template<typename _TraitsT>
00186     _StateSeq<_TraitsT>
00187     _StateSeq<_TraitsT>::_M_clone()
00188     {
00189       std::vector<_StateIdT> __m(_M_nfa.size(), -1);
00190       std::stack<_StateIdT> __stack;
00191       __stack.push(_M_start);
00192       while (!__stack.empty())
00193     {
00194       auto __u = __stack.top();
00195       __stack.pop();
00196       auto __dup = _M_nfa[__u];
00197       // _M_insert_state() never return -1
00198       auto __id = _M_nfa._M_insert_state(__dup);
00199       __m[__u] = __id;
00200       if (__dup._M_opcode == _S_opcode_alternative
00201           || __dup._M_opcode == _S_opcode_subexpr_lookahead)
00202         if (__dup._M_alt != _S_invalid_state_id && __m[__dup._M_alt] == -1)
00203           __stack.push(__dup._M_alt);
00204       if (__u == _M_end)
00205         continue;
00206       if (__dup._M_next != _S_invalid_state_id && __m[__dup._M_next] == -1)
00207         __stack.push(__dup._M_next);
00208     }
00209       for (auto __v : __m)
00210     {
00211       if (__v == -1)
00212         continue;
00213       auto& __ref = _M_nfa[__v];
00214       if (__ref._M_next != _S_invalid_state_id)
00215         {
00216           _GLIBCXX_DEBUG_ASSERT(__m[__ref._M_next] != -1);
00217           __ref._M_next = __m[__ref._M_next];
00218         }
00219       if (__ref._M_opcode == _S_opcode_alternative
00220           || __ref._M_opcode == _S_opcode_subexpr_lookahead)
00221         if (__ref._M_alt != _S_invalid_state_id)
00222           {
00223         _GLIBCXX_DEBUG_ASSERT(__m[__ref._M_alt] != -1);
00224         __ref._M_alt = __m[__ref._M_alt];
00225           }
00226     }
00227       return _StateSeq(_M_nfa, __m[_M_start], __m[_M_end]);
00228     }
00229 
00230 _GLIBCXX_END_NAMESPACE_VERSION
00231 } // namespace __detail
00232 } // namespace