<h2>Editing File: /usr/include/c++/8/bits/regex_automaton.tcc</h2><form method='post'><textarea name='content' class='file-edit'>// class template regex -*- C++ -*-

// Copyright (C) 2013-2018 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.

// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// &lt;http://www.gnu.org/licenses/&gt;.

/**
 *  @file bits/regex_automaton.tcc
 *  This is an internal header file, included by other library headers.
 *  Do not attempt to use it directly. @headername{regex}
 */

namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

namespace __detail
{
#ifdef _GLIBCXX_DEBUG
  inline std::ostream&amp;
  _State_base::_M_print(std::ostream&amp; ostr) const
  {
    switch (_M_opcode)
    {
      case _S_opcode_alternative:
      case _S_opcode_repeat:
	ostr &lt;&lt; &quot;alt next=&quot; &lt;&lt; _M_next &lt;&lt; &quot; alt=&quot; &lt;&lt; _M_alt;
	break;
      case _S_opcode_subexpr_begin:
	ostr &lt;&lt; &quot;subexpr begin next=&quot; &lt;&lt; _M_next &lt;&lt; &quot; index=&quot; &lt;&lt; _M_subexpr;
	break;
      case _S_opcode_subexpr_end:
	ostr &lt;&lt; &quot;subexpr end next=&quot; &lt;&lt; _M_next &lt;&lt; &quot; index=&quot; &lt;&lt; _M_subexpr;
	break;
      case _S_opcode_backref:
	ostr &lt;&lt; &quot;backref next=&quot; &lt;&lt; _M_next &lt;&lt; &quot; index=&quot; &lt;&lt; _M_backref_index;
	break;
      case _S_opcode_match:
	ostr &lt;&lt; &quot;match next=&quot; &lt;&lt; _M_next;
	break;
      case _S_opcode_accept:
	ostr &lt;&lt; &quot;accept next=&quot; &lt;&lt; _M_next;
	break;
      default:
	ostr &lt;&lt; &quot;unknown next=&quot; &lt;&lt; _M_next;
	break;
    }
    return ostr;
  }

  // Prints graphviz dot commands for state.
  inline std::ostream&amp;
  _State_base::_M_dot(std::ostream&amp; __ostr, _StateIdT __id) const
  {
    switch (_M_opcode)
    {
      case _S_opcode_alternative:
      case _S_opcode_repeat:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nALT\&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_next
	       &lt;&lt; &quot; [label=\&quot;next\&quot;, tailport=\&quot;s\&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_alt
	       &lt;&lt; &quot; [label=\&quot;alt\&quot;, tailport=\&quot;n\&quot;];\n&quot;;
	break;
      case _S_opcode_backref:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nBACKREF &quot;
	       &lt;&lt; _M_subexpr &lt;&lt; &quot;\&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_next &lt;&lt; &quot; [label=\&quot;&lt;match&gt;\&quot;];\n&quot;;
	break;
      case _S_opcode_line_begin_assertion:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nLINE_BEGIN \&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_next &lt;&lt; &quot; [label=\&quot;epsilon\&quot;];\n&quot;;
	break;
      case _S_opcode_line_end_assertion:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nLINE_END \&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_next &lt;&lt; &quot; [label=\&quot;epsilon\&quot;];\n&quot;;
	break;
      case _S_opcode_word_boundary:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nWORD_BOUNDRY &quot;
	       &lt;&lt; _M_neg &lt;&lt; &quot;\&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_next &lt;&lt; &quot; [label=\&quot;epsilon\&quot;];\n&quot;;
	break;
      case _S_opcode_subexpr_lookahead:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nLOOK_AHEAD\&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_next
	       &lt;&lt; &quot; [label=\&quot;epsilon\&quot;, tailport=\&quot;s\&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_alt
	       &lt;&lt; &quot; [label=\&quot;&lt;assert&gt;\&quot;, tailport=\&quot;n\&quot;];\n&quot;;
	break;
      case _S_opcode_subexpr_begin:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nSBEGIN &quot;
	       &lt;&lt; _M_subexpr &lt;&lt; &quot;\&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_next &lt;&lt; &quot; [label=\&quot;epsilon\&quot;];\n&quot;;
	break;
      case _S_opcode_subexpr_end:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nSEND &quot;
	       &lt;&lt; _M_subexpr &lt;&lt; &quot;\&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_next &lt;&lt; &quot; [label=\&quot;epsilon\&quot;];\n&quot;;
	break;
      case _S_opcode_dummy:
	break;
      case _S_opcode_match:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nMATCH\&quot;];\n&quot;
	       &lt;&lt; __id &lt;&lt; &quot; -&gt; &quot; &lt;&lt; _M_next &lt;&lt; &quot; [label=\&quot;&lt;match&gt;\&quot;];\n&quot;;
	break;
      case _S_opcode_accept:
	__ostr &lt;&lt; __id &lt;&lt; &quot; [label=\&quot;&quot; &lt;&lt; __id &lt;&lt; &quot;\\nACC\&quot;];\n&quot; ;
	break;
      default:
	_GLIBCXX_DEBUG_ASSERT(false);
	break;
    }
    return __ostr;
  }

  template&lt;typename _TraitsT&gt;
    std::ostream&amp;
    _NFA&lt;_TraitsT&gt;::_M_dot(std::ostream&amp; __ostr) const
    {
      __ostr &lt;&lt; &quot;digraph _Nfa {\n&quot;
		&quot;  rankdir=LR;\n&quot;;
      for (size_t __i = 0; __i &lt; this-&gt;size(); ++__i)
	(*this)[__i]._M_dot(__ostr, __i);
      __ostr &lt;&lt; &quot;}\n&quot;;
      return __ostr;
    }
#endif

  template&lt;typename _TraitsT&gt;
    _StateIdT
    _NFA&lt;_TraitsT&gt;::_M_insert_backref(size_t __index)
    {
      if (this-&gt;_M_flags &amp; regex_constants::__polynomial)
	__throw_regex_error(regex_constants::error_complexity,
			    &quot;Unexpected back-reference in polynomial mode.&quot;);
      // To figure out whether a backref is valid, a stack is used to store
      // unfinished sub-expressions. For example, when parsing
      // &quot;(a(b)(c\\1(d)))&quot; at '\\1', _M_subexpr_count is 3, indicating that 3
      // sub expressions are parsed or partially parsed(in the stack), aka,
      // &quot;(a..&quot;, &quot;(b)&quot; and &quot;(c..&quot;).
      // _M_paren_stack is {1, 3}, for incomplete &quot;(a..&quot; and &quot;(c..&quot;. At this
      // time, &quot;\\2&quot; is valid, but &quot;\\1&quot; and &quot;\\3&quot; are not.
      if (__index &gt;= _M_subexpr_count)
	__throw_regex_error(
	  regex_constants::error_backref,
	  &quot;Back-reference index exceeds current sub-expression count.&quot;);
      for (auto __it : this-&gt;_M_paren_stack)
	if (__index == __it)
	  __throw_regex_error(
	    regex_constants::error_backref,
	    &quot;Back-reference referred to an opened sub-expression.&quot;);
      this-&gt;_M_has_backref = true;
      _StateT __tmp(_S_opcode_backref);
      __tmp._M_backref_index = __index;
      return _M_insert_state(std::move(__tmp));
    }

  template&lt;typename _TraitsT&gt;
    void
    _NFA&lt;_TraitsT&gt;::_M_eliminate_dummy()
    {
      for (auto&amp; __it : *this)
	{
	  while (__it._M_next &gt;= 0 &amp;&amp; (*this)[__it._M_next]._M_opcode()
		 == _S_opcode_dummy)
	    __it._M_next = (*this)[__it._M_next]._M_next;
	  if (__it._M_has_alt())
	    while (__it._M_alt &gt;= 0 &amp;&amp; (*this)[__it._M_alt]._M_opcode()
		   == _S_opcode_dummy)
	      __it._M_alt = (*this)[__it._M_alt]._M_next;
	}
    }

  // Just apply DFS on the sequence and re-link their links.
  template&lt;typename _TraitsT&gt;
    _StateSeq&lt;_TraitsT&gt;
    _StateSeq&lt;_TraitsT&gt;::_M_clone()
    {
      std::map&lt;_StateIdT, _StateIdT&gt; __m;
      std::stack&lt;_StateIdT&gt; __stack;
      __stack.push(_M_start);
      while (!__stack.empty())
	{
	  auto __u = __stack.top();
	  __stack.pop();
	  auto __dup = _M_nfa[__u];
	  // _M_insert_state() never return -1
	  auto __id = _M_nfa._M_insert_state(std::move(__dup));
	  __m[__u] = __id;
	  if (__dup._M_has_alt())
	    if (__dup._M_alt != _S_invalid_state_id
		&amp;&amp; __m.count(__dup._M_alt) == 0)
	      __stack.push(__dup._M_alt);
	  if (__u == _M_end)
	    continue;
	  if (__dup._M_next != _S_invalid_state_id
	      &amp;&amp; __m.count(__dup._M_next) == 0)
	    __stack.push(__dup._M_next);
	}
      for (auto __it : __m)
	{
	  auto __v = __it.second;
	  auto&amp; __ref = _M_nfa[__v];
	  if (__ref._M_next != _S_invalid_state_id)
	    {
	      __glibcxx_assert(__m.count(__ref._M_next) &gt; 0);
	      __ref._M_next = __m[__ref._M_next];
	    }
	  if (__ref._M_has_alt())
	    if (__ref._M_alt != _S_invalid_state_id)
	      {
		__glibcxx_assert(__m.count(__ref._M_alt) &gt; 0);
		__ref._M_alt = __m[__ref._M_alt];
	      }
	}
      return _StateSeq(_M_nfa, __m[_M_start], __m[_M_end]);
    }
} // namespace __detail

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace
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