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// class template regex -*- C++ -*- |
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// Copyright (C) 2013-2021 Free Software Foundation, Inc. |
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// |
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// This file is part of the GNU ISO C++ Library. This library is free |
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// software; you can redistribute it and/or modify it under the |
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// terms of the GNU General Public License as published by the |
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// Free Software Foundation; either version 3, or (at your option) |
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// any later version. |
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|
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// This library is distributed in the hope that it will be useful, |
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// but WITHOUT ANY WARRANTY; without even the implied warranty of |
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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// GNU General Public License for more details. |
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|
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// Under Section 7 of GPL version 3, you are granted additional |
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// permissions described in the GCC Runtime Library Exception, version |
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// 3.1, as published by the Free Software Foundation. |
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|
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// You should have received a copy of the GNU General Public License and |
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// a copy of the GCC Runtime Library Exception along with this program; |
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
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// <http://www.gnu.org/licenses/>. |
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|
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/** |
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* @file bits/regex_automaton.h |
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* This is an internal header file, included by other library headers. |
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* Do not attempt to use it directly. @headername{regex} |
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*/ |
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|
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// This macro defines the maximal state number a NFA can have. |
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#ifndef _GLIBCXX_REGEX_STATE_LIMIT |
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#define _GLIBCXX_REGEX_STATE_LIMIT 100000 |
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#endif |
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|
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namespace std _GLIBCXX_VISIBILITY(default) |
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{ |
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_GLIBCXX_BEGIN_NAMESPACE_VERSION |
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|
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namespace __detail |
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{ |
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/** |
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* @defgroup regex-detail Base and Implementation Classes |
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* @ingroup regex |
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* @{ |
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*/ |
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|
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typedef long _StateIdT; |
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static const _StateIdT _S_invalid_state_id = -1; |
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|
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template<typename _CharT> |
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using _Matcher = std::function<bool (_CharT)>; |
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|
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/// Operation codes that define the type of transitions within the base NFA |
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/// that represents the regular expression. |
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enum _Opcode : int |
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{ |
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_S_opcode_unknown, |
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_S_opcode_alternative, |
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_S_opcode_repeat, |
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_S_opcode_backref, |
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_S_opcode_line_begin_assertion, |
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_S_opcode_line_end_assertion, |
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_S_opcode_word_boundary, |
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_S_opcode_subexpr_lookahead, |
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_S_opcode_subexpr_begin, |
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_S_opcode_subexpr_end, |
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_S_opcode_dummy, |
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_S_opcode_match, |
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_S_opcode_accept, |
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}; |
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|
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struct _State_base |
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{ |
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protected: |
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_Opcode _M_opcode; // type of outgoing transition |
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|
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public: |
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_StateIdT _M_next; // outgoing transition |
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union // Since they are mutually exclusive. |
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{ |
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size_t _M_subexpr; // for _S_opcode_subexpr_* |
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size_t _M_backref_index; // for _S_opcode_backref |
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struct |
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{ |
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// for _S_opcode_alternative, _S_opcode_repeat and |
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// _S_opcode_subexpr_lookahead |
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_StateIdT _M_alt; |
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// for _S_opcode_word_boundary or _S_opcode_subexpr_lookahead or |
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// quantifiers (ungreedy if set true) |
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bool _M_neg; |
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}; |
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// For _S_opcode_match |
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__gnu_cxx::__aligned_membuf<_Matcher<char>> _M_matcher_storage; |
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}; |
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|
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protected: |
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explicit _State_base(_Opcode __opcode) |
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: _M_opcode(__opcode), _M_next(_S_invalid_state_id) |
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{ } |
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|
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public: |
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bool |
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_M_has_alt() |
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{ |
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return _M_opcode == _S_opcode_alternative |
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|| _M_opcode == _S_opcode_repeat |
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|| _M_opcode == _S_opcode_subexpr_lookahead; |
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} |
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|
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#ifdef _GLIBCXX_DEBUG |
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std::ostream& |
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_M_print(std::ostream& ostr) const; |
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|
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// Prints graphviz dot commands for state. |
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std::ostream& |
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_M_dot(std::ostream& __ostr, _StateIdT __id) const; |
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#endif |
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}; |
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|
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template<typename _Char_type> |
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struct _State : _State_base |
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{ |
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typedef _Matcher<_Char_type> _MatcherT; |
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static_assert(sizeof(_MatcherT) == sizeof(_Matcher<char>), |
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"std::function<bool(T)> has the same size as " |
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"std::function<bool(char)>"); |
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static_assert(alignof(_MatcherT) == alignof(_Matcher<char>), |
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"std::function<bool(T)> has the same alignment as " |
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"std::function<bool(char)>"); |
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|
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explicit |
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_State(_Opcode __opcode) : _State_base(__opcode) |
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{ |
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if (_M_opcode() == _S_opcode_match) |
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new (this->_M_matcher_storage._M_addr()) _MatcherT(); |
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} |
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_State(const _State& __rhs) : _State_base(__rhs) |
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{ |
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if (__rhs._M_opcode() == _S_opcode_match) |
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new (this->_M_matcher_storage._M_addr()) |
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_MatcherT(__rhs._M_get_matcher()); |
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} |
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|
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_State(_State&& __rhs) : _State_base(__rhs) |
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{ |
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if (__rhs._M_opcode() == _S_opcode_match) |
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new (this->_M_matcher_storage._M_addr()) |
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_MatcherT(std::move(__rhs._M_get_matcher())); |
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} |
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|
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_State& |
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operator=(const _State&) = delete; |
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|
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~_State() |
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{ |
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if (_M_opcode() == _S_opcode_match) |
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_M_get_matcher().~_MatcherT(); |
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} |
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// Since correct ctor and dtor rely on _M_opcode, it's better not to |
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// change it over time. |
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_Opcode |
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_M_opcode() const |
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{ return _State_base::_M_opcode; } |
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|
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bool |
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_M_matches(_Char_type __char) const |
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{ return _M_get_matcher()(__char); } |
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|
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_MatcherT& |
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_M_get_matcher() |
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{ return *static_cast<_MatcherT*>(this->_M_matcher_storage._M_addr()); } |
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|
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const _MatcherT& |
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_M_get_matcher() const |
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{ |
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return *static_cast<const _MatcherT*>( |
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this->_M_matcher_storage._M_addr()); |
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} |
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}; |
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|
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struct _NFA_base |
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{ |
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typedef size_t _SizeT; |
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typedef regex_constants::syntax_option_type _FlagT; |
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|
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explicit |
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_NFA_base(_FlagT __f) |
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: _M_flags(__f), _M_start_state(0), _M_subexpr_count(0), |
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_M_has_backref(false) |
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{ } |
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_NFA_base(_NFA_base&&) = default; |
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|
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protected: |
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~_NFA_base() = default; |
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|
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public: |
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_FlagT |
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_M_options() const |
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{ return _M_flags; } |
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|
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_StateIdT |
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_M_start() const |
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{ return _M_start_state; } |
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|
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_SizeT |
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_M_sub_count() const |
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{ return _M_subexpr_count; } |
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|
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_GLIBCXX_STD_C::vector<size_t> _M_paren_stack; |
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_FlagT _M_flags; |
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_StateIdT _M_start_state; |
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_SizeT _M_subexpr_count; |
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bool _M_has_backref; |
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}; |
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|
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template<typename _TraitsT> |
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struct _NFA |
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: _NFA_base, _GLIBCXX_STD_C::vector<_State<typename _TraitsT::char_type>> |
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{ |
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typedef typename _TraitsT::char_type _Char_type; |
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typedef _State<_Char_type> _StateT; |
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typedef _Matcher<_Char_type> _MatcherT; |
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|
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_NFA(const typename _TraitsT::locale_type& __loc, _FlagT __flags) |
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: _NFA_base(__flags) |
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{ _M_traits.imbue(__loc); } |
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|
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// for performance reasons _NFA objects should only be moved not copied |
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_NFA(const _NFA&) = delete; |
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_NFA(_NFA&&) = default; |
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|
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_StateIdT |
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_M_insert_accept() |
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{ |
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auto __ret = _M_insert_state(_StateT(_S_opcode_accept)); |
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return __ret; |
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} |
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|
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_StateIdT |
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_M_insert_alt(_StateIdT __next, _StateIdT __alt, |
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bool __neg __attribute__((__unused__))) |
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{ |
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_StateT __tmp(_S_opcode_alternative); |
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// It labels every quantifier to make greedy comparison easier in BFS |
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// approach. |
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__tmp._M_next = __next; |
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__tmp._M_alt = __alt; |
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return _M_insert_state(std::move(__tmp)); |
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} |
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|
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_StateIdT |
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_M_insert_repeat(_StateIdT __next, _StateIdT __alt, bool __neg) |
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{ |
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_StateT __tmp(_S_opcode_repeat); |
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// It labels every quantifier to make greedy comparison easier in BFS |
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// approach. |
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__tmp._M_next = __next; |
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__tmp._M_alt = __alt; |
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__tmp._M_neg = __neg; |
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return _M_insert_state(std::move(__tmp)); |
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} |
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|
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_StateIdT |
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_M_insert_matcher(_MatcherT __m) |
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{ |
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_StateT __tmp(_S_opcode_match); |
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__tmp._M_get_matcher() = std::move(__m); |
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return _M_insert_state(std::move(__tmp)); |
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} |
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|
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_StateIdT |
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_M_insert_subexpr_begin() |
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{ |
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auto __id = this->_M_subexpr_count++; |
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this->_M_paren_stack.push_back(__id); |
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_StateT __tmp(_S_opcode_subexpr_begin); |
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__tmp._M_subexpr = __id; |
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return _M_insert_state(std::move(__tmp)); |
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} |
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|
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_StateIdT |
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_M_insert_subexpr_end() |
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{ |
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_StateT __tmp(_S_opcode_subexpr_end); |
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__tmp._M_subexpr = this->_M_paren_stack.back(); |
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this->_M_paren_stack.pop_back(); |
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return _M_insert_state(std::move(__tmp)); |
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} |
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|
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_StateIdT |
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_M_insert_backref(size_t __index); |
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|
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_StateIdT |
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_M_insert_line_begin() |
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{ return _M_insert_state(_StateT(_S_opcode_line_begin_assertion)); } |
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|
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_StateIdT |
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_M_insert_line_end() |
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{ return _M_insert_state(_StateT(_S_opcode_line_end_assertion)); } |
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|
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_StateIdT |
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_M_insert_word_bound(bool __neg) |
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{ |
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_StateT __tmp(_S_opcode_word_boundary); |
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__tmp._M_neg = __neg; |
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return _M_insert_state(std::move(__tmp)); |
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} |
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|
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_StateIdT |
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_M_insert_lookahead(_StateIdT __alt, bool __neg) |
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{ |
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_StateT __tmp(_S_opcode_subexpr_lookahead); |
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__tmp._M_alt = __alt; |
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__tmp._M_neg = __neg; |
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return _M_insert_state(std::move(__tmp)); |
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} |
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|
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_StateIdT |
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_M_insert_dummy() |
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{ return _M_insert_state(_StateT(_S_opcode_dummy)); } |
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|
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_StateIdT |
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_M_insert_state(_StateT __s) |
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{ |
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this->push_back(std::move(__s)); |
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if (this->size() > _GLIBCXX_REGEX_STATE_LIMIT) |
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__throw_regex_error( |
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regex_constants::error_space, |
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"Number of NFA states exceeds limit. Please use shorter regex " |
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"string, or use smaller brace expression, or make " |
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"_GLIBCXX_REGEX_STATE_LIMIT larger."); |
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return this->size() - 1; |
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} |
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// Eliminate dummy node in this NFA to make it compact. |
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void |
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_M_eliminate_dummy(); |
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|
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#ifdef _GLIBCXX_DEBUG |
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std::ostream& |
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_M_dot(std::ostream& __ostr) const; |
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#endif |
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public: |
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_TraitsT _M_traits; |
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}; |
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|
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/// Describes a sequence of one or more %_State, its current start |
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/// and end(s). This structure contains fragments of an NFA during |
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/// construction. |
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template<typename _TraitsT> |
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class _StateSeq |
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{ |
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public: |
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typedef _NFA<_TraitsT> _RegexT; |
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|
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public: |
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_StateSeq(_RegexT& __nfa, _StateIdT __s) |
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: _M_nfa(__nfa), _M_start(__s), _M_end(__s) |
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{ } |
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|
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_StateSeq(_RegexT& __nfa, _StateIdT __s, _StateIdT __end) |
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: _M_nfa(__nfa), _M_start(__s), _M_end(__end) |
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{ } |
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|
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// Append a state on *this and change *this to the new sequence. |
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void |
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_M_append(_StateIdT __id) |
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{ |
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_M_nfa[_M_end]._M_next = __id; |
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_M_end = __id; |
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} |
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|
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// Append a sequence on *this and change *this to the new sequence. |
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void |
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_M_append(const _StateSeq& __s) |
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{ |
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_M_nfa[_M_end]._M_next = __s._M_start; |
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_M_end = __s._M_end; |
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} |
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|
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// Clones an entire sequence. |
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_StateSeq |
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_M_clone(); |
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|
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public: |
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_RegexT& _M_nfa; |
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_StateIdT _M_start; |
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_StateIdT _M_end; |
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}; |
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|
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///@} regex-detail |
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} // namespace __detail |
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|
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_GLIBCXX_END_NAMESPACE_VERSION |
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} // namespace std |
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|
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#include <bits/regex_automaton.tcc> |
