// class template regex -*- C++ -*- // Copyright (C) 2013-2022 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 // . /** * @file bits/regex_scanner.tcc * This is an internal header file, included by other library headers. * Do not attempt to use it directly. @headername{regex} */ // FIXME make comments doxygen format. // N3376 specified 6 regex styles: ECMAScript, basic, extended, grep, egrep // and awk // 1) grep is basic except '\n' is treated as '|' // 2) egrep is extended except '\n' is treated as '|' // 3) awk is extended except special escaping rules, and there's no // back-reference. // // References: // // ECMAScript: ECMA-262 15.10 // // basic, extended: // http://pubs.opengroup.org/onlinepubs/009695399/basedefs/xbd_chap09.html // // awk: http://pubs.opengroup.org/onlinepubs/000095399/utilities/awk.html namespace std _GLIBCXX_VISIBILITY(default) { _GLIBCXX_BEGIN_NAMESPACE_VERSION namespace __detail { template _Scanner<_CharT>:: _Scanner(const _CharT* __begin, const _CharT* __end, _FlagT __flags, std::locale __loc) : _ScannerBase(__flags), _M_current(__begin), _M_end(__end), _M_ctype(std::use_facet<_CtypeT>(__loc)), _M_eat_escape(_M_is_ecma() ? &_Scanner::_M_eat_escape_ecma : &_Scanner::_M_eat_escape_posix) { _M_advance(); } template void _Scanner<_CharT>:: _M_advance() { if (_M_current == _M_end) { _M_token = _S_token_eof; return; } if (_M_state == _S_state_normal) _M_scan_normal(); else if (_M_state == _S_state_in_bracket) _M_scan_in_bracket(); else if (_M_state == _S_state_in_brace) _M_scan_in_brace(); else { __glibcxx_assert(!"unexpected state while processing regex"); } } // Differences between styles: // 1) "\(", "\)", "\{" in basic. It's not escaping. // 2) "(?:", "(?=", "(?!" in ECMAScript. template void _Scanner<_CharT>:: _M_scan_normal() { auto __c = *_M_current++; if (__builtin_strchr(_M_spec_char, _M_ctype.narrow(__c, ' ')) == nullptr) { _M_token = _S_token_ord_char; _M_value.assign(1, __c); return; } if (__c == '\\') { if (_M_current == _M_end) __throw_regex_error( regex_constants::error_escape, "Invalid escape at end of regular expression"); if (!_M_is_basic() || (*_M_current != '(' && *_M_current != ')' && *_M_current != '{')) { (this->*_M_eat_escape)(); return; } __c = *_M_current++; } if (__c == '(') { if (_M_is_ecma() && *_M_current == '?') { if (++_M_current == _M_end) __throw_regex_error(regex_constants::error_paren); if (*_M_current == ':') { ++_M_current; _M_token = _S_token_subexpr_no_group_begin; } else if (*_M_current == '=') { ++_M_current; _M_token = _S_token_subexpr_lookahead_begin; _M_value.assign(1, 'p'); } else if (*_M_current == '!') { ++_M_current; _M_token = _S_token_subexpr_lookahead_begin; _M_value.assign(1, 'n'); } else __throw_regex_error(regex_constants::error_paren, "Invalid '(?...)' zero-width assertion " "in regular expression"); } else if (_M_flags & regex_constants::nosubs) _M_token = _S_token_subexpr_no_group_begin; else _M_token = _S_token_subexpr_begin; } else if (__c == ')') _M_token = _S_token_subexpr_end; else if (__c == '[') { _M_state = _S_state_in_bracket; _M_at_bracket_start = true; if (_M_current != _M_end && *_M_current == '^') { _M_token = _S_token_bracket_neg_begin; ++_M_current; } else _M_token = _S_token_bracket_begin; } else if (__c == '{') { _M_state = _S_state_in_brace; _M_token = _S_token_interval_begin; } else if (__builtin_expect(__c == _CharT(0), false)) { if (!_M_is_ecma()) __throw_regex_error(regex_constants::_S_null); _M_token = _S_token_ord_char; _M_value.assign(1, __c); } else if (__c != ']' && __c != '}') { auto __it = _M_token_tbl; auto __narrowc = _M_ctype.narrow(__c, '\0'); for (; __it->first != '\0'; ++__it) if (__it->first == __narrowc) { _M_token = __it->second; return; } __glibcxx_assert(!"unexpected special character in regex"); } else { _M_token = _S_token_ord_char; _M_value.assign(1, __c); } } // Differences between styles: // 1) different semantics of "[]" and "[^]". // 2) Escaping in bracket expr. template void _Scanner<_CharT>:: _M_scan_in_bracket() { if (_M_current == _M_end) __throw_regex_error(regex_constants::error_brack); auto __c = *_M_current++; if (__c == '-') _M_token = _S_token_bracket_dash; else if (__c == '[') { if (_M_current == _M_end) __throw_regex_error(regex_constants::error_brack, "Incomplete '[[' character class in " "regular expression"); if (*_M_current == '.') { _M_token = _S_token_collsymbol; _M_eat_class(*_M_current++); } else if (*_M_current == ':') { _M_token = _S_token_char_class_name; _M_eat_class(*_M_current++); } else if (*_M_current == '=') { _M_token = _S_token_equiv_class_name; _M_eat_class(*_M_current++); } else { _M_token = _S_token_ord_char; _M_value.assign(1, __c); } } // In POSIX, when encountering "[]" or "[^]", the ']' is interpreted // literally. So "[]]" and "[^]]" are valid regexes. See the testcases // `.../empty_range.cc`. else if (__c == ']' && (_M_is_ecma() || !_M_at_bracket_start)) { _M_token = _S_token_bracket_end; _M_state = _S_state_normal; } // ECMAScript and awk permits escaping in bracket. else if (__c == '\\' && (_M_is_ecma() || _M_is_awk())) (this->*_M_eat_escape)(); else { _M_token = _S_token_ord_char; _M_value.assign(1, __c); } _M_at_bracket_start = false; } // Differences between styles: // 1) "\}" in basic style. template void _Scanner<_CharT>:: _M_scan_in_brace() { if (_M_current == _M_end) __throw_regex_error(regex_constants::error_brace); auto __c = *_M_current++; if (_M_ctype.is(_CtypeT::digit, __c)) { _M_token = _S_token_dup_count; _M_value.assign(1, __c); while (_M_current != _M_end && _M_ctype.is(_CtypeT::digit, *_M_current)) _M_value += *_M_current++; } else if (__c == ',') _M_token = _S_token_comma; // basic use \}. else if (_M_is_basic()) { if (__c == '\\' && _M_current != _M_end && *_M_current == '}') { _M_state = _S_state_normal; _M_token = _S_token_interval_end; ++_M_current; } else __throw_regex_error(regex_constants::error_badbrace); } else if (__c == '}') { _M_state = _S_state_normal; _M_token = _S_token_interval_end; } else __throw_regex_error(regex_constants::error_badbrace); } template void _Scanner<_CharT>:: _M_eat_escape_ecma() { if (_M_current == _M_end) __throw_regex_error(regex_constants::error_escape); auto __c = *_M_current++; auto __pos = _M_find_escape(_M_ctype.narrow(__c, '\0')); if (__pos != nullptr && (__c != 'b' || _M_state == _S_state_in_bracket)) { _M_token = _S_token_ord_char; _M_value.assign(1, *__pos); } else if (__c == 'b') { _M_token = _S_token_word_bound; _M_value.assign(1, 'p'); } else if (__c == 'B') { _M_token = _S_token_word_bound; _M_value.assign(1, 'n'); } // N3376 28.13 else if (__c == 'd' || __c == 'D' || __c == 's' || __c == 'S' || __c == 'w' || __c == 'W') { _M_token = _S_token_quoted_class; _M_value.assign(1, __c); } else if (__c == 'c') { if (_M_current == _M_end) __throw_regex_error(regex_constants::error_escape, "invalid '\\cX' control character in " "regular expression"); _M_token = _S_token_ord_char; _M_value.assign(1, *_M_current++); } else if (__c == 'x' || __c == 'u') { _M_value.clear(); const int __n = __c == 'x' ? 2 : 4; for (int __i = 0; __i < __n; __i++) { if (_M_current == _M_end || !_M_ctype.is(_CtypeT::xdigit, *_M_current)) __throw_regex_error(regex_constants::error_escape, __n == 2 ? "Invalid '\\xNN' control character in " "regular expression" : "Invalid '\\uNNNN' control character in " "regular expression"); _M_value += *_M_current++; } _M_token = _S_token_hex_num; } // ECMAScript recognizes multi-digit back-references. else if (_M_ctype.is(_CtypeT::digit, __c)) { _M_value.assign(1, __c); while (_M_current != _M_end && _M_ctype.is(_CtypeT::digit, *_M_current)) _M_value += *_M_current++; _M_token = _S_token_backref; } else { _M_token = _S_token_ord_char; _M_value.assign(1, __c); } } // Differences between styles: // 1) Extended doesn't support backref, but basic does. template void _Scanner<_CharT>:: _M_eat_escape_posix() { if (_M_current == _M_end) __throw_regex_error(regex_constants::error_escape); auto __c = *_M_current; auto __pos = __builtin_strchr(_M_spec_char, _M_ctype.narrow(__c, '\0')); if (__pos != nullptr && *__pos != '\0') { _M_token = _S_token_ord_char; _M_value.assign(1, __c); } // We MUST judge awk before handling backrefs. There's no backref in awk. else if (_M_is_awk()) { _M_eat_escape_awk(); return; } else if (_M_is_basic() && _M_ctype.is(_CtypeT::digit, __c) && __c != '0') { _M_token = _S_token_backref; _M_value.assign(1, __c); } else { #ifdef __STRICT_ANSI__ // POSIX says it is undefined to escape ordinary characters __throw_regex_error(regex_constants::error_escape); #else _M_token = _S_token_ord_char; _M_value.assign(1, __c); #endif } ++_M_current; } template void _Scanner<_CharT>:: _M_eat_escape_awk() { auto __c = *_M_current++; auto __pos = _M_find_escape(_M_ctype.narrow(__c, '\0')); if (__pos != nullptr) { _M_token = _S_token_ord_char; _M_value.assign(1, *__pos); } // \ddd for oct representation else if (_M_ctype.is(_CtypeT::digit, __c) && __c != '8' && __c != '9') { _M_value.assign(1, __c); for (int __i = 0; __i < 2 && _M_current != _M_end && _M_ctype.is(_CtypeT::digit, *_M_current) && *_M_current != '8' && *_M_current != '9'; __i++) _M_value += *_M_current++; _M_token = _S_token_oct_num; return; } else __throw_regex_error(regex_constants::error_escape); } // Eats a character class or throws an exception. // __ch could be ':', '.' or '=', _M_current is the char after ']' when // returning. template void _Scanner<_CharT>:: _M_eat_class(char __ch) { for (_M_value.clear(); _M_current != _M_end && *_M_current != __ch;) _M_value += *_M_current++; if (_M_current == _M_end || *_M_current++ != __ch || _M_current == _M_end // skip __ch || *_M_current++ != ']') // skip ']' { __throw_regex_error(__ch == ':' ? regex_constants::error_ctype : regex_constants::error_collate); } } #ifdef _GLIBCXX_DEBUG template std::ostream& _Scanner<_CharT>:: _M_print(std::ostream& ostr) { switch (_M_token) { case _S_token_anychar: ostr << "any-character\n"; break; case _S_token_backref: ostr << "backref\n"; break; case _S_token_bracket_begin: ostr << "bracket-begin\n"; break; case _S_token_bracket_neg_begin: ostr << "bracket-neg-begin\n"; break; case _S_token_bracket_end: ostr << "bracket-end\n"; break; case _S_token_char_class_name: ostr << "char-class-name \"" << _M_value << "\"\n"; break; case _S_token_closure0: ostr << "closure0\n"; break; case _S_token_closure1: ostr << "closure1\n"; break; case _S_token_collsymbol: ostr << "collsymbol \"" << _M_value << "\"\n"; break; case _S_token_comma: ostr << "comma\n"; break; case _S_token_dup_count: ostr << "dup count: " << _M_value << "\n"; break; case _S_token_eof: ostr << "EOF\n"; break; case _S_token_equiv_class_name: ostr << "equiv-class-name \"" << _M_value << "\"\n"; break; case _S_token_interval_begin: ostr << "interval begin\n"; break; case _S_token_interval_end: ostr << "interval end\n"; break; case _S_token_line_begin: ostr << "line begin\n"; break; case _S_token_line_end: ostr << "line end\n"; break; case _S_token_opt: ostr << "opt\n"; break; case _S_token_or: ostr << "or\n"; break; case _S_token_ord_char: ostr << "ordinary character: \"" << _M_value << "\"\n"; break; case _S_token_subexpr_begin: ostr << "subexpr begin\n"; break; case _S_token_subexpr_no_group_begin: ostr << "no grouping subexpr begin\n"; break; case _S_token_subexpr_lookahead_begin: ostr << "lookahead subexpr begin\n"; break; case _S_token_subexpr_end: ostr << "subexpr end\n"; break; case _S_token_unknown: ostr << "-- unknown token --\n"; break; case _S_token_oct_num: ostr << "oct number " << _M_value << "\n"; break; case _S_token_hex_num: ostr << "hex number " << _M_value << "\n"; break; case _S_token_quoted_class: ostr << "quoted class " << "\\" << _M_value << "\n"; break; default: _GLIBCXX_DEBUG_ASSERT(false); } return ostr; } #endif } // namespace __detail _GLIBCXX_END_NAMESPACE_VERSION } // namespace