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  #   §ˆl–Ü4ý(”†»â‚À¹q§Å£ß„_uÏÂÝ .È    §// Debugging bitset implementation -*- C++ -*-

// Copyright (C) 2003-2021 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 debug/bitset
 *  This file is a GNU debug extension to the Standard C++ Library.
 */

#ifndef _GLIBCXX_DEBUG_BITSET
#define _GLIBCXX_DEBUG_BITSET

#pragma GCC system_header

#include <bitset>
#include <debug/safe_sequence.h>
#include <debug/safe_iterator.h>

namespace std _GLIBCXX_VISIBILITY(default)
{
namespace __debug
{
  /// Class std::bitset with additional safety/checking/debug instrumentation.
  template<size_t _Nb>
    class bitset
    : public _GLIBCXX_STD_C::bitset<_Nb>
#if __cplusplus < 201103L
    , public __gnu_debug::_Safe_sequence_base
#endif
    {
      typedef _GLIBCXX_STD_C::bitset<_Nb> _Base;

    public:
      // In C++11 we rely on normal reference type to preserve the property
      // of bitset to be use as a literal.
      // TODO: Find another solution.
#if __cplusplus >= 201103L
      typedef typename _Base::reference reference;
#else
      // bit reference:
      class reference
      : private _Base::reference
        , public __gnu_debug::_Safe_iterator_base
      {
	typedef typename _Base::reference _Base_ref;

	friend class bitset;
	reference();

	reference(const _Base_ref& __base, bitset* __seq) _GLIBCXX_NOEXCEPT
	: _Base_ref(__base)
	, _Safe_iterator_base(__seq, false)
	{ }

      public:
	reference(const reference& __x) _GLIBCXX_NOEXCEPT
	: _Base_ref(__x)
	, _Safe_iterator_base(__x, false)
	{ }

	reference&
	operator=(bool __x) _GLIBCXX_NOEXCEPT
	{
	  _GLIBCXX_DEBUG_VERIFY(!this->_M_singular(),
			      _M_message(__gnu_debug::__msg_bad_bitset_write)
				._M_iterator(*this));
	  *static_cast<_Base_ref*>(this) = __x;
	  return *this;
	}

	reference&
	operator=(const reference& __x) _GLIBCXX_NOEXCEPT
	{
	  _GLIBCXX_DEBUG_VERIFY(!__x._M_singular(),
			       _M_message(__gnu_debug::__msg_bad_bitset_read)
				._M_iterator(__x));
	  _GLIBCXX_DEBUG_VERIFY(!this->_M_singular(),
			      _M_message(__gnu_debug::__msg_bad_bitset_write)
				._M_iterator(*this));
	  *static_cast<_Base_ref*>(this) = __x;
	  return *this;
	}

	bool
	operator~() const _GLIBCXX_NOEXCEPT
	{
	  _GLIBCXX_DEBUG_VERIFY(!this->_M_singular(),
			       _M_message(__gnu_debug::__msg_bad_bitset_read)
				._M_iterator(*this));
	  return ~(*static_cast<const _Base_ref*>(this));
	}

	operator bool() const _GLIBCXX_NOEXCEPT
	{
	  _GLIBCXX_DEBUG_VERIFY(!this->_M_singular(),
			      _M_message(__gnu_debug::__msg_bad_bitset_read)
				._M_iterator(*this));
	  return *static_cast<const _Base_ref*>(this);
	}

	reference&
	flip() _GLIBCXX_NOEXCEPT
	{
	  _GLIBCXX_DEBUG_VERIFY(!this->_M_singular(),
			      _M_message(__gnu_debug::__msg_bad_bitset_flip)
				._M_iterator(*this));
	  _Base_ref::flip();
	  return *this;
	}
      };
#endif

      // 23.3.5.1 constructors:
      _GLIBCXX_CONSTEXPR bitset() _GLIBCXX_NOEXCEPT
      : _Base() { }

#if __cplusplus >= 201103L
      constexpr bitset(unsigned long long __val) noexcept
#else
      bitset(unsigned long __val)
#endif
      : _Base(__val) { }

      templ