regex_grep_matcher.tcc File Reference

#include <regex>

Functions
namespace std	_GLIBCXX_VISIBILITY (default)

Detailed Description

This is an internal header file, included by other library headers. Do not attempt to use it directly. {regex}

Function Documentation

namespace std _GLIBCXX_VISIBILITY

(

default

)

{
namespace
{
  // A stack of states used in evaluating the NFA.
  typedef std::stack<std::__detail::_StateIdT,
                     std::vector<std::__detail::_StateIdT>
             > _StateStack;

  // Obtains the next state set given the current state set __s and the current
  // input character.
  inline std::__detail::_StateSet
  __move(const std::__detail::_PatternCursor& __p,
         const std::__detail::_Nfa& __nfa,
         const std::__detail::_StateSet& __s)
  {
    std::__detail::_StateSet __m;
    for (std::__detail::_StateSet::const_iterator __i = __s.begin();
     __i != __s.end(); ++__i)
      {
    if (*__i == std::__detail::_S_invalid_state_id)
      continue;

    const std::__detail::_State& __state = __nfa[*__i];
    if (__state._M_opcode == std::__detail::_S_opcode_match
        && __state._M_matches(__p))
      __m.insert(__state._M_next);
      }
    return __m;
  }

  // returns true if (__s intersect __t) is not empty
  inline bool
  __includes_some(const std::__detail::_StateSet& __s,
                  const std::__detail::_StateSet& __t)
  {
    if (__s.size() > 0 && __t.size() > 0)
      {
    std::__detail::_StateSet::const_iterator __first = __s.begin();
    std::__detail::_StateSet::const_iterator __second = __t.begin();
    while (__first != __s.end() && __second != __t.end())
      {
        if (*__first < *__second)
          ++__first;
        else if (*__second < *__first)
          ++__second;
        else
          return true;
      }
      }
    return false;
  }

  // If an identified state __u is not already in the current state set __e,
  // insert it and push it on the current state stack __s.
  inline void
  __add_visited_state(const std::__detail::_StateIdT __u,
                      _StateStack&                  __s,
                      std::__detail::_StateSet&      __e)
  {
    if (__e.count(__u) == 0)
      {
    __e.insert(__u);
    __s.push(__u);
      }
  }

} // anonymous namespace

namespace __detail
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION

  inline _Grep_matcher::
  _Grep_matcher(_PatternCursor& __p, _Results& __r,
        const _AutomatonPtr& __nfa,
        regex_constants::match_flag_type __flags)
  : _M_nfa(static_pointer_cast<_Nfa>(__nfa)), _M_pattern(__p), _M_results(__r)
  {
    __detail::_StateSet __t = this->_M_e_closure(_M_nfa->_M_start());
    for (; !_M_pattern._M_at_end(); _M_pattern._M_next())
      __t = this->_M_e_closure(__move(_M_pattern, *_M_nfa, __t));

    _M_results._M_set_matched(0,
                              __includes_some(_M_nfa->_M_final_states(), __t));
  }

  // Creates the e-closure set for the initial state __i.
  inline _StateSet _Grep_matcher::
  _M_e_closure(_StateIdT __i)
  {
    _StateSet __s;
    __s.insert(__i);
    _StateStack __stack;
    __stack.push(__i);
    return this->_M_e_closure(__stack, __s);
  }

  // Creates the e-closure set for an arbitrary state set __s.
  inline _StateSet _Grep_matcher::
  _M_e_closure(const _StateSet& __s)
  {
    _StateStack __stack;
    for (_StateSet::const_iterator __i = __s.begin(); __i != __s.end(); ++__i)
      __stack.push(*__i);
    return this->_M_e_closure(__stack, __s);
  }

  inline _StateSet _Grep_matcher::
  _M_e_closure(_StateStack& __stack, const _StateSet& __s)
  {
    _StateSet __e = __s;
    while (!__stack.empty())
      {
    _StateIdT __t = __stack.top(); __stack.pop();
    if (__t == _S_invalid_state_id)
      continue;
    // for each __u with edge from __t to __u labeled e do ...
    const _State& __state = _M_nfa->operator[](__t);
    switch (__state._M_opcode)
      {
      case _S_opcode_alternative:
        __add_visited_state(__state._M_next, __stack, __e);
        __add_visited_state(__state._M_alt, __stack, __e);
        break;
      case _S_opcode_subexpr_begin:
        __add_visited_state(__state._M_next, __stack, __e);
        __state._M_tagger(_M_pattern, _M_results);
        break;
      case _S_opcode_subexpr_end:
        __add_visited_state(__state._M_next, __stack, __e);
        __state._M_tagger(_M_pattern, _M_results);
        _M_results._M_set_matched(__state._M_subexpr, true);
        break;
      case _S_opcode_accept:
        __add_visited_state(__state._M_next, __stack, __e);
        break;
      default:
        break;
      }
      }
    return __e;
  }

_GLIBCXX_END_NAMESPACE_VERSION
} // namespace __detail
} // namespace