regex_scanner.h
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// class template regex -*- C++ -*-
// Copyright (C) 2013-2023 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
// <http://www.gnu.org/licenses/>.
/**
* @file bits/regex_scanner.h
* 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
{
/**
* @addtogroup regex-detail
* @{
*/
struct _ScannerBase
{
public:
/// Token types returned from the scanner.
enum _TokenT : unsigned
{
_S_token_anychar,
_S_token_ord_char,
_S_token_oct_num,
_S_token_hex_num,
_S_token_backref,
_S_token_subexpr_begin,
_S_token_subexpr_no_group_begin,
_S_token_subexpr_lookahead_begin, // neg if _M_value[0] == 'n'
_S_token_subexpr_end,
_S_token_bracket_begin,
_S_token_bracket_neg_begin,
_S_token_bracket_end,
_S_token_interval_begin,
_S_token_interval_end,
_S_token_quoted_class,
_S_token_char_class_name,
_S_token_collsymbol,
_S_token_equiv_class_name,
_S_token_opt,
_S_token_or,
_S_token_closure0,
_S_token_closure1,
_S_token_line_begin,
_S_token_line_end,
_S_token_word_bound, // neg if _M_value[0] == 'n'
_S_token_comma,
_S_token_dup_count,
_S_token_eof,
_S_token_bracket_dash,
_S_token_unknown = -1u
};
protected:
typedef regex_constants::syntax_option_type _FlagT;
enum _StateT
{
_S_state_normal,
_S_state_in_brace,
_S_state_in_bracket,
};
protected:
_ScannerBase(_FlagT __flags)
: _M_state(_S_state_normal),
_M_flags(__flags),
_M_escape_tbl(_M_is_ecma()
? _M_ecma_escape_tbl
: _M_awk_escape_tbl),
_M_spec_char(_M_is_ecma()
? _M_ecma_spec_char
: _M_flags & regex_constants::basic
? _M_basic_spec_char
: _M_flags & regex_constants::extended
? _M_extended_spec_char
: _M_flags & regex_constants::grep
? ".[\\*^$\n"
: _M_flags & regex_constants::egrep
? ".[\\()*+?{|^$\n"
: _M_flags & regex_constants::awk
? _M_extended_spec_char
: nullptr),
_M_at_bracket_start(false)
{ __glibcxx_assert(_M_spec_char); }
protected:
const char*
_M_find_escape(char __c)
{
auto __it = _M_escape_tbl;
for (; __it->first != '\0'; ++__it)
if (__it->first == __c)
return &__it->second;
return nullptr;
}
bool
_M_is_ecma() const
{ return _M_flags & regex_constants::ECMAScript; }
bool
_M_is_basic() const
{ return _M_flags & (regex_constants::basic | regex_constants::grep); }
bool
_M_is_extended() const
{
return _M_flags & (regex_constants::extended
| regex_constants::egrep
| regex_constants::awk);
}
bool
_M_is_grep() const
{ return _M_flags & (regex_constants::grep | regex_constants::egrep); }
bool
_M_is_awk() const
{ return _M_flags & regex_constants::awk; }
protected:
// TODO: Make them static in the next abi change.
const std::pair<char, _TokenT> _M_token_tbl[9] =
{
{'^', _S_token_line_begin},
{'$', _S_token_line_end},
{'.', _S_token_anychar},
{'*', _S_token_closure0},
{'+', _S_token_closure1},
{'?', _S_token_opt},
{'|', _S_token_or},
{'\n', _S_token_or}, // grep and egrep
{'\0', _S_token_or},
};
const std::pair<char, char> _M_ecma_escape_tbl[8] =
{
{'0', '\0'},
{'b', '\b'},
{'f', '\f'},
{'n', '\n'},
{'r', '\r'},
{'t', '\t'},
{'v', '\v'},
{'\0', '\0'},
};
const std::pair<char, char> _M_awk_escape_tbl[11] =
{
{'"', '"'},
{'/', '/'},
{'\\', '\\'},
{'a', '\a'},
{'b', '\b'},
{'f', '\f'},
{'n', '\n'},
{'r', '\r'},
{'t', '\t'},
{'v', '\v'},
{'\0', '\0'},
};
const char* _M_ecma_spec_char = "^$\\.*+?()[]{}|";
const char* _M_basic_spec_char = ".[\\*^$";
const char* _M_extended_spec_char = ".[\\()*+?{|^$";
_StateT _M_state;
_FlagT _M_flags;
_TokenT _M_token;
const std::pair<char, char>* _M_escape_tbl;
const char* _M_spec_char;
bool _M_at_bracket_start;
};
/**
* @brief Scans an input range for regex tokens.
*
* The %_Scanner class interprets the regular expression pattern in
* the input range passed to its constructor as a sequence of parse
* tokens passed to the regular expression compiler. The sequence
* of tokens provided depends on the flag settings passed to the
* constructor: different regular expression grammars will interpret
* the same input pattern in syntactically different ways.
*/
template<typename _CharT>
class _Scanner
: public _ScannerBase
{
public:
typedef std::basic_string<_CharT> _StringT;
typedef regex_constants::syntax_option_type _FlagT;
typedef const std::ctype<_CharT> _CtypeT;
_Scanner(const _CharT* __begin, const _CharT* __end,
_FlagT __flags, std::locale __loc);
void
_M_advance();
_TokenT
_M_get_token() const noexcept
{ return _M_token; }
const _StringT&
_M_get_value() const noexcept
{ return _M_value; }
#ifdef _GLIBCXX_DEBUG
std::ostream&
_M_print(std::ostream&);
#endif
private:
void
_M_scan_normal();
void
_M_scan_in_bracket();
void
_M_scan_in_brace();
void
_M_eat_escape_ecma();
void
_M_eat_escape_posix();
void
_M_eat_escape_awk();
void
_M_eat_class(char);
const _CharT* _M_current;
const _CharT* _M_end;
_CtypeT& _M_ctype;
_StringT _M_value;
void (_Scanner::* _M_eat_escape)();
};
///@} regex-detail
} // namespace __detail
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
#include <bits/regex_scanner.tcc>
regex_scanner.tcc
std::ostream
basic_ostream< char > ostream
Base class for char output streams.
Definition iosfwd:143
std
ISO C++ entities toplevel namespace is std.
std::__detail
Implementation details not part of the namespace std interface.
std::regex_constants::ECMAScript
constexpr syntax_option_type ECMAScript
Definition regex_constants.h:120
std::regex_constants::egrep
constexpr syntax_option_type egrep
Definition regex_constants.h:163
std::regex_constants::syntax_option_type
syntax_option_type
This is a bitmask type indicating how to interpret the regex.
Definition regex_constants.h:70
std::regex_constants::awk
constexpr syntax_option_type awk
Definition regex_constants.h:147
std::regex_constants::extended
constexpr syntax_option_type extended
Definition regex_constants.h:137
std::regex_constants::basic
constexpr syntax_option_type basic
Definition regex_constants.h:129
std::regex_constants::grep
constexpr syntax_option_type grep
Definition regex_constants.h:155
std::basic_string
Managing sequences of characters and character-like objects.
Definition basic_string.h:88
std::locale
Container class for localization functionality.
Definition locale_classes.h:63
std::ctype
Primary class template ctype facet.
Definition locale_facets.h:616