bool_set
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// TR2 <bool_set> -*- C++ -*-
// Copyright (C) 2009-2023 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 tr2/bool_set
* This is a TR2 C++ Library header.
*/
#ifndef _GLIBCXX_TR2_BOOL_SET
#define _GLIBCXX_TR2_BOOL_SET 1
#pragma GCC system_header
#include <typeinfo>
#include <iostream>
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
namespace tr2
{
/**
* bool_set
*
* See N2136, Bool_set: multi-valued logic
* by Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion.
*
* The implicit conversion to bool is slippery! I may use the new
* explicit conversion. This has been specialized in the language
* so that in contexts requiring a bool the conversion happens
* implicitly. Thus most objections should be eliminated.
*/
class bool_set
{
public:
/// Default constructor.
constexpr bool_set() : _M_b(_S_false) { }
/// Constructor from bool.
constexpr bool_set(bool __t) : _M_b(_Bool_set_val(__t)) { }
// I'm not sure about this.
bool contains(bool_set __b) const
{ return this->is_singleton() && this->equals(__b); }
/// Return true if states are equal.
bool equals(bool_set __b) const
{ return __b._M_b == _M_b; }
/// Return true if this is empty.
bool is_emptyset() const
{ return _M_b == _S_empty; }
/// Return true if this is indeterminate.
bool is_indeterminate() const
{ return _M_b == _S_indet; }
/// Return true if this is false or true (normal boolean).
bool is_singleton() const
{ return _M_b == _S_false || _M_b == _S_true_; }
/// Conversion to bool.
//explicit
operator bool() const
{
if (! is_singleton())
throw std::bad_cast();
return _M_b;
}
///
static bool_set indeterminate()
{
bool_set __b;
__b._M_b = _S_indet;
return __b;
}
///
static bool_set emptyset()
{
bool_set __b;
__b._M_b = _S_empty;
return __b;
}
friend bool_set
operator!(bool_set __b)
{ return __b._M_not(); }
friend bool_set
operator^(bool_set __s, bool_set __t)
{ return __s._M_xor(__t); }
friend bool_set
operator|(bool_set __s, bool_set __t)
{ return __s._M_or(__t); }
friend bool_set
operator&(bool_set __s, bool_set __t)
{ return __s._M_and(__t); }
friend bool_set
operator==(bool_set __s, bool_set __t)
{ return __s._M_eq(__t); }
// These overloads replace the facet additions in the paper!
template<typename CharT, typename Traits>
friend std::basic_ostream<CharT, Traits>&
operator<<(std::basic_ostream<CharT, Traits>& __out, bool_set __b)
{
int __a = __b._M_b;
__out << __a;
}
template<typename CharT, typename Traits>
friend std::basic_istream<CharT, Traits>&
operator>>(std::basic_istream<CharT, Traits>& __in, bool_set& __b)
{
long __c;
__in >> __c;
if (__c >= _S_false && __c < _S_empty)
__b._M_b = static_cast<_Bool_set_val>(__c);
}
private:
///
enum _Bool_set_val: unsigned char
{
_S_false = 0,
_S_true_ = 1,
_S_indet = 2,
_S_empty = 3
};
/// Bool set state.
_Bool_set_val _M_b;
///
bool_set(_Bool_set_val __c) : _M_b(__c) { }
///
bool_set _M_not() const
{ return _S_not[this->_M_b]; }
///
bool_set _M_xor(bool_set __b) const
{ return _S_xor[this->_M_b][__b._M_b]; }
///
bool_set _M_or(bool_set __b) const
{ return _S_or[this->_M_b][__b._M_b]; }
///
bool_set _M_and(bool_set __b) const
{ return _S_and[this->_M_b][__b._M_b]; }
///
bool_set _M_eq(bool_set __b) const
{ return _S_eq[this->_M_b][__b._M_b]; }
///
static _Bool_set_val _S_not[4];
///
static _Bool_set_val _S_xor[4][4];
///
static _Bool_set_val _S_or[4][4];
///
static _Bool_set_val _S_and[4][4];
///
static _Bool_set_val _S_eq[4][4];
};
// 20.2.3.2 bool_set values
inline bool
contains(bool_set __s, bool_set __t)
{ return __s.contains(__t); }
inline bool
equals(bool_set __s, bool_set __t)
{ return __s.equals(__t); }
inline bool
is_emptyset(bool_set __b)
{ return __b.is_emptyset(); }
inline bool
is_indeterminate(bool_set __b)
{ return __b.is_indeterminate(); }
inline bool
is_singleton(bool_set __b)
{ return __b.is_singleton(); }
inline bool
certainly(bool_set __b)
{ return ! __b.contains(false); }
inline bool
possibly(bool_set __b)
{ return __b.contains(true); }
// 20.2.3.3 bool_set set operations
inline bool_set
set_union(bool __s, bool_set __t)
{ return bool_set(__s) | __t; }
inline bool_set
set_union(bool_set __s, bool __t)
{ return __s | bool_set(__t); }
inline bool_set
set_union(bool_set __s, bool_set __t)
{ return __s | __t; }
inline bool_set
set_intersection(bool __s, bool_set __t)
{ return bool_set(__s) & __t; }
inline bool_set
set_intersection(bool_set __s, bool __t)
{ return __s & bool_set(__t); }
inline bool_set
set_intersection(bool_set __s, bool_set __t)
{ return __s & __t; }
inline bool_set
set_complement(bool_set __b)
{ return ! __b; }
// 20.2.3.4 bool_set logical operators
inline bool_set
operator^(bool __s, bool_set __t)
{ return bool_set(__s) ^ __t; }
inline bool_set
operator^(bool_set __s, bool __t)
{ return __s ^ bool_set(__t); }
inline bool_set
operator|(bool __s, bool_set __t)
{ return bool_set(__s) | __t; }
inline bool_set
operator|(bool_set __s, bool __t)
{ return __s | bool_set(__t); }
inline bool_set
operator&(bool __s, bool_set __t)
{ return bool_set(__s) & __t; }
inline bool_set
operator&(bool_set __s, bool __t)
{ return __s & bool_set(__t); }
// 20.2.3.5 bool_set relational operators
inline bool_set
operator==(bool __s, bool_set __t)
{ return bool_set(__s) == __t; }
inline bool_set
operator==(bool_set __s, bool __t)
{ return __s == bool_set(__t); }
inline bool_set
operator!=(bool __s, bool_set __t)
{ return ! (__s == __t); }
inline bool_set
operator!=(bool_set __s, bool __t)
{ return ! (__s == __t); }
inline bool_set
operator!=(bool_set __s, bool_set __t)
{ return ! (__s == __t); }
}
_GLIBCXX_END_NAMESPACE_VERSION
}
#include <tr2/bool_set.tcc>
#endif // _GLIBCXX_TR2_BOOL_SET