321 lines
7.2 KiB
C++
321 lines
7.2 KiB
C++
// TR2 <bool_set> -*- C++ -*-
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// Copyright (C) 2009-2020 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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// 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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// 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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// 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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/** @file tr2/bool_set
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* This is a TR2 C++ Library header.
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*/
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#ifndef _GLIBCXX_TR2_BOOL_SET
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#define _GLIBCXX_TR2_BOOL_SET 1
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#pragma GCC system_header
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#include <typeinfo>
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#include <iostream>
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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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namespace tr2
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{
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/**
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* bool_set
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*
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* See N2136, Bool_set: multi-valued logic
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* by Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion.
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*
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* The implicit conversion to bool is slippery! I may use the new
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* explicit conversion. This has been specialized in the language
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* so that in contexts requiring a bool the conversion happens
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* implicitly. Thus most objections should be eliminated.
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*/
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class bool_set
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{
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public:
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/// Default constructor.
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constexpr bool_set() : _M_b(_S_false) { }
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/// Constructor from bool.
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constexpr bool_set(bool __t) : _M_b(_Bool_set_val(__t)) { }
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// I'm not sure about this.
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bool contains(bool_set __b) const
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{ return this->is_singleton() && this->equals(__b); }
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/// Return true if states are equal.
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bool equals(bool_set __b) const
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{ return __b._M_b == _M_b; }
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/// Return true if this is empty.
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bool is_emptyset() const
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{ return _M_b == _S_empty; }
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/// Return true if this is indeterminate.
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bool is_indeterminate() const
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{ return _M_b == _S_indet; }
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/// Return true if this is false or true (normal boolean).
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bool is_singleton() const
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{ return _M_b == _S_false || _M_b == _S_true_; }
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/// Conversion to bool.
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//explicit
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operator bool() const
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{
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if (! is_singleton())
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throw std::bad_cast();
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return _M_b;
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}
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///
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static bool_set indeterminate()
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{
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bool_set __b;
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__b._M_b = _S_indet;
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return __b;
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}
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///
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static bool_set emptyset()
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{
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bool_set __b;
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__b._M_b = _S_empty;
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return __b;
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}
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friend bool_set
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operator!(bool_set __b)
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{ return __b._M_not(); }
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friend bool_set
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operator^(bool_set __s, bool_set __t)
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{ return __s._M_xor(__t); }
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friend bool_set
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operator|(bool_set __s, bool_set __t)
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{ return __s._M_or(__t); }
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friend bool_set
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operator&(bool_set __s, bool_set __t)
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{ return __s._M_and(__t); }
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friend bool_set
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operator==(bool_set __s, bool_set __t)
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{ return __s._M_eq(__t); }
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// These overloads replace the facet additions in the paper!
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template<typename CharT, typename Traits>
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friend std::basic_ostream<CharT, Traits>&
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operator<<(std::basic_ostream<CharT, Traits>& __out, bool_set __b)
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{
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int __a = __b._M_b;
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__out << __a;
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}
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template<typename CharT, typename Traits>
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friend std::basic_istream<CharT, Traits>&
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operator>>(std::basic_istream<CharT, Traits>& __in, bool_set& __b)
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{
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long __c;
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__in >> __c;
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if (__c >= _S_false && __c < _S_empty)
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__b._M_b = static_cast<_Bool_set_val>(__c);
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}
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private:
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///
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enum _Bool_set_val: unsigned char
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{
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_S_false = 0,
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_S_true_ = 1,
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_S_indet = 2,
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_S_empty = 3
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};
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/// Bool set state.
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_Bool_set_val _M_b;
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///
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bool_set(_Bool_set_val __c) : _M_b(__c) { }
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///
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bool_set _M_not() const
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{ return _S_not[this->_M_b]; }
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///
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bool_set _M_xor(bool_set __b) const
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{ return _S_xor[this->_M_b][__b._M_b]; }
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///
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bool_set _M_or(bool_set __b) const
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{ return _S_or[this->_M_b][__b._M_b]; }
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///
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bool_set _M_and(bool_set __b) const
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{ return _S_and[this->_M_b][__b._M_b]; }
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///
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bool_set _M_eq(bool_set __b) const
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{ return _S_eq[this->_M_b][__b._M_b]; }
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///
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static _Bool_set_val _S_not[4];
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///
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static _Bool_set_val _S_xor[4][4];
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///
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static _Bool_set_val _S_or[4][4];
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///
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static _Bool_set_val _S_and[4][4];
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///
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static _Bool_set_val _S_eq[4][4];
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};
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// 20.2.3.2 bool_set values
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inline bool
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contains(bool_set __s, bool_set __t)
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{ return __s.contains(__t); }
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inline bool
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equals(bool_set __s, bool_set __t)
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{ return __s.equals(__t); }
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inline bool
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is_emptyset(bool_set __b)
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{ return __b.is_emptyset(); }
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inline bool
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is_indeterminate(bool_set __b)
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{ return __b.is_indeterminate(); }
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inline bool
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is_singleton(bool_set __b)
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{ return __b.is_singleton(); }
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inline bool
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certainly(bool_set __b)
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{ return ! __b.contains(false); }
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inline bool
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possibly(bool_set __b)
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{ return __b.contains(true); }
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// 20.2.3.3 bool_set set operations
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inline bool_set
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set_union(bool __s, bool_set __t)
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{ return bool_set(__s) | __t; }
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inline bool_set
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set_union(bool_set __s, bool __t)
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{ return __s | bool_set(__t); }
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inline bool_set
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set_union(bool_set __s, bool_set __t)
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{ return __s | __t; }
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inline bool_set
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set_intersection(bool __s, bool_set __t)
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{ return bool_set(__s) & __t; }
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inline bool_set
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set_intersection(bool_set __s, bool __t)
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{ return __s & bool_set(__t); }
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inline bool_set
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set_intersection(bool_set __s, bool_set __t)
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{ return __s & __t; }
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inline bool_set
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set_complement(bool_set __b)
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{ return ! __b; }
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// 20.2.3.4 bool_set logical operators
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inline bool_set
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operator^(bool __s, bool_set __t)
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{ return bool_set(__s) ^ __t; }
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inline bool_set
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operator^(bool_set __s, bool __t)
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{ return __s ^ bool_set(__t); }
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inline bool_set
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operator|(bool __s, bool_set __t)
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{ return bool_set(__s) | __t; }
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inline bool_set
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operator|(bool_set __s, bool __t)
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{ return __s | bool_set(__t); }
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inline bool_set
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operator&(bool __s, bool_set __t)
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{ return bool_set(__s) & __t; }
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inline bool_set
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operator&(bool_set __s, bool __t)
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{ return __s & bool_set(__t); }
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// 20.2.3.5 bool_set relational operators
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inline bool_set
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operator==(bool __s, bool_set __t)
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{ return bool_set(__s) == __t; }
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inline bool_set
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operator==(bool_set __s, bool __t)
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{ return __s == bool_set(__t); }
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inline bool_set
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operator!=(bool __s, bool_set __t)
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{ return ! (__s == __t); }
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inline bool_set
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operator!=(bool_set __s, bool __t)
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{ return ! (__s == __t); }
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inline bool_set
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operator!=(bool_set __s, bool_set __t)
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{ return ! (__s == __t); }
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}
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_GLIBCXX_END_NAMESPACE_VERSION
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}
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#include <tr2/bool_set.tcc>
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#endif // _GLIBCXX_TR2_BOOL_SET
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