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  1. // TR2 <bool_set> -*- C++ -*-
  2.  
  3. // Copyright (C) 2009-2015 Free Software Foundation, Inc.
  4. //
  5. // This file is part of the GNU ISO C++ Library.  This library is free
  6. // software; you can redistribute it and/or modify it under the
  7. // terms of the GNU General Public License as published by the
  8. // Free Software Foundation; either version 3, or (at your option)
  9. // any later version.
  10.  
  11. // This library is distributed in the hope that it will be useful,
  12. // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13. // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14. // GNU General Public License for more details.
  15.  
  16. // Under Section 7 of GPL version 3, you are granted additional
  17. // permissions described in the GCC Runtime Library Exception, version
  18. // 3.1, as published by the Free Software Foundation.
  19.  
  20. // You should have received a copy of the GNU General Public License and
  21. // a copy of the GCC Runtime Library Exception along with this program;
  22. // see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23. // <http://www.gnu.org/licenses/>.
  24.  
  25. /** @file tr2/bool_set
  26.  *  This is a TR2 C++ Library header.
  27.  */
  28.  
  29. #ifndef _GLIBCXX_TR2_BOOL_SET
  30. #define _GLIBCXX_TR2_BOOL_SET 1
  31.  
  32. #pragma GCC system_header
  33.  
  34. #include <typeinfo>
  35. #include <iostream>
  36.  
  37. namespace std _GLIBCXX_VISIBILITY(default)
  38. {
  39. namespace tr2
  40. {
  41. _GLIBCXX_BEGIN_NAMESPACE_VERSION
  42.  
  43.   /**
  44.    *  bool_set
  45.    *
  46.    *  See N2136, Bool_set: multi-valued logic
  47.    *  by Hervé Brönnimann, Guillaume Melquiond, Sylvain Pion.
  48.    *
  49.    *  The implicit conversion to bool is slippery!  I may use the new
  50.    *  explicit conversion.  This has been specialized in the language
  51.    *  so that in contexts requiring a bool the conversion happens
  52.    *  implicitly.  Thus most objections should be eliminated.
  53.    */
  54.   class bool_set
  55.   {
  56.   public:
  57.  
  58.     ///  Default constructor.
  59.     constexpr bool_set() : _M_b(_S_false) { }
  60.  
  61.     ///  Constructor from bool.
  62.     constexpr bool_set(bool __t) : _M_b(_Bool_set_val(__t)) { }
  63.  
  64.     // I'm not sure about this.
  65.     bool contains(bool_set __b) const
  66.     { return this->is_singleton() && this->equals(__b); }
  67.  
  68.     ///  Return true if states are equal.
  69.     bool equals(bool_set __b) const
  70.     { return __b._M_b == _M_b; }
  71.  
  72.     ///  Return true if this is empty.
  73.     bool is_emptyset() const
  74.     { return _M_b == _S_empty; }
  75.  
  76.     ///  Return true if this is indeterminate.
  77.     bool is_indeterminate() const
  78.     { return _M_b == _S_indet; }
  79.  
  80.     ///  Return true if this is false or true (normal boolean).
  81.     bool is_singleton() const
  82.     { return _M_b == _S_false || _M_b == _S_true_; }
  83.  
  84.     ///  Conversion to bool.
  85.     //explicit
  86.     operator bool() const
  87.     {
  88.       if (! is_singleton())
  89.         throw std::bad_cast();
  90.       return _M_b;
  91.     }
  92.  
  93.     ///
  94.     static bool_set indeterminate()
  95.     {
  96.       bool_set __b;
  97.       __b._M_b = _S_indet;
  98.       return __b;
  99.     }
  100.  
  101.     ///
  102.     static bool_set emptyset()
  103.     {
  104.       bool_set __b;
  105.       __b._M_b = _S_empty;
  106.       return __b;
  107.     }
  108.  
  109.     friend bool_set
  110.     operator!(bool_set __b)
  111.     { return __b._M_not(); }
  112.  
  113.     friend bool_set
  114.     operator^(bool_set __s, bool_set __t)
  115.     { return __s._M_xor(__t); }
  116.  
  117.     friend bool_set
  118.     operator|(bool_set __s, bool_set __t)
  119.     { return __s._M_or(__t); }
  120.  
  121.     friend bool_set
  122.     operator&(bool_set __s, bool_set __t)
  123.     { return __s._M_and(__t); }
  124.  
  125.     friend bool_set
  126.     operator==(bool_set __s, bool_set __t)
  127.     { return __s._M_eq(__t); }
  128.  
  129.  
  130.     //  These overloads replace the facet additions in the paper!
  131.  
  132.     template<typename CharT, typename Traits>
  133.       friend std::basic_ostream<CharT, Traits>&
  134.       operator<<(std::basic_ostream<CharT, Traits>& __out, bool_set __b)
  135.       {
  136.         int __a = __b._M_b;
  137.         __out << __a;
  138.       }
  139.  
  140.     template<typename CharT, typename Traits>
  141.       friend std::basic_istream<CharT, Traits>&
  142.       operator>>(std::basic_istream<CharT, Traits>& __in, bool_set& __b)
  143.       {
  144.         long __c;
  145.         __in >> __c;
  146.         if (__c >= _S_false && __c < _S_empty)
  147.           __b._M_b = static_cast<_Bool_set_val>(__c);
  148.       }
  149.  
  150.   private:
  151.  
  152.     ///
  153.     enum _Bool_set_val: unsigned char
  154.     {
  155.       _S_false = 0,
  156.       _S_true_ = 1,
  157.       _S_indet = 2,
  158.       _S_empty = 3
  159.     };
  160.  
  161.     ///  Bool set state.
  162.     _Bool_set_val _M_b;
  163.  
  164.     ///
  165.     bool_set(_Bool_set_val __c) : _M_b(__c) { }
  166.  
  167.     ///
  168.     bool_set _M_not() const
  169.     { return _S_not[this->_M_b]; }
  170.  
  171.     ///
  172.     bool_set _M_xor(bool_set __b) const
  173.     { return _S_xor[this->_M_b][__b._M_b]; }
  174.  
  175.     ///
  176.     bool_set _M_or(bool_set __b) const
  177.     { return _S_or[this->_M_b][__b._M_b]; }
  178.  
  179.     ///
  180.     bool_set _M_and(bool_set __b) const
  181.     { return _S_and[this->_M_b][__b._M_b]; }
  182.  
  183.     ///
  184.     bool_set _M_eq(bool_set __b) const
  185.     { return _S_eq[this->_M_b][__b._M_b]; }
  186.  
  187.     ///
  188.     static _Bool_set_val _S_not[4];
  189.  
  190.     ///
  191.     static _Bool_set_val _S_xor[4][4];
  192.  
  193.     ///
  194.     static _Bool_set_val _S_or[4][4];
  195.  
  196.     ///
  197.     static _Bool_set_val _S_and[4][4];
  198.  
  199.     ///
  200.     static _Bool_set_val _S_eq[4][4];
  201.   };
  202.  
  203.   //  20.2.3.2 bool_set values
  204.  
  205.   inline bool
  206.   contains(bool_set __s, bool_set __t)
  207.   { return __s.contains(__t); }
  208.  
  209.   inline bool
  210.   equals(bool_set __s, bool_set __t)
  211.   { return __s.equals(__t); }
  212.  
  213.   inline bool
  214.   is_emptyset(bool_set __b)
  215.   { return __b.is_emptyset(); }
  216.  
  217.   inline bool
  218.   is_indeterminate(bool_set __b)
  219.   { return __b.is_indeterminate(); }
  220.  
  221.   inline bool
  222.   is_singleton(bool_set __b)
  223.   { return __b.is_singleton(); }
  224.  
  225.   inline bool
  226.   certainly(bool_set __b)
  227.   { return ! __b.contains(false); }
  228.  
  229.   inline bool
  230.   possibly(bool_set __b)
  231.   { return __b.contains(true); }
  232.  
  233.  
  234.   //  20.2.3.3 bool_set set operations
  235.  
  236.   inline bool_set
  237.   set_union(bool __s, bool_set __t)
  238.   { return bool_set(__s) | __t; }
  239.  
  240.   inline bool_set
  241.   set_union(bool_set __s, bool __t)
  242.   { return __s | bool_set(__t); }
  243.  
  244.   inline bool_set
  245.   set_union(bool_set __s, bool_set __t)
  246.   { return __s | __t; }
  247.  
  248.   inline bool_set
  249.   set_intersection(bool __s, bool_set __t)
  250.   { return bool_set(__s) & __t; }
  251.  
  252.   inline bool_set
  253.   set_intersection(bool_set __s, bool __t)
  254.   { return __s & bool_set(__t); }
  255.  
  256.   inline bool_set
  257.   set_intersection(bool_set __s, bool_set __t)
  258.   { return __s & __t; }
  259.  
  260.   inline bool_set
  261.   set_complement(bool_set __b)
  262.   { return ! __b; }
  263.  
  264.  
  265.   //  20.2.3.4 bool_set logical operators
  266.  
  267.   inline bool_set
  268.   operator^(bool __s, bool_set __t)
  269.   { return bool_set(__s) ^ __t; }
  270.  
  271.   inline bool_set
  272.   operator^(bool_set __s, bool __t)
  273.   { return __s ^ bool_set(__t); }
  274.  
  275.   inline bool_set
  276.   operator|(bool __s, bool_set __t)
  277.   { return bool_set(__s) | __t; }
  278.  
  279.   inline bool_set
  280.   operator|(bool_set __s, bool __t)
  281.   { return __s | bool_set(__t); }
  282.  
  283.   inline bool_set
  284.   operator&(bool __s, bool_set __t)
  285.   { return bool_set(__s) & __t; }
  286.  
  287.   inline bool_set
  288.   operator&(bool_set __s, bool __t)
  289.   { return __s & bool_set(__t); }
  290.  
  291.  
  292.   //  20.2.3.5 bool_set relational operators
  293.  
  294.   inline bool_set
  295.   operator==(bool __s, bool_set __t)
  296.   { return bool_set(__s) == __t; }
  297.  
  298.   inline bool_set
  299.   operator==(bool_set __s, bool __t)
  300.   { return __s == bool_set(__t); }
  301.  
  302.   inline bool_set
  303.   operator!=(bool __s, bool_set __t)
  304.   { return ! (__s == __t); }
  305.  
  306.   inline bool_set
  307.   operator!=(bool_set __s, bool __t)
  308.   { return ! (__s == __t); }
  309.  
  310.   inline bool_set
  311.   operator!=(bool_set __s, bool_set __t)
  312.   { return ! (__s == __t); }
  313.  
  314. _GLIBCXX_END_NAMESPACE_VERSION
  315. }
  316. }
  317.  
  318. #include <tr2/bool_set.tcc>
  319.  
  320. #endif // _GLIBCXX_TR2_BOOL_SET
  321.