WSJT-X/boost/boost/logic/tribool.hpp

470 lines
14 KiB
C++

// Three-state boolean logic library
// Copyright Douglas Gregor 2002-2004. Use, modification and
// distribution is subject to the Boost Software License, Version
// 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// For more information, see http://www.boost.org
#ifndef BOOST_LOGIC_TRIBOOL_HPP
#define BOOST_LOGIC_TRIBOOL_HPP
#include <boost/logic/tribool_fwd.hpp>
#include <boost/config.hpp>
#include <boost/detail/workaround.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
# pragma once
#endif
namespace boost { namespace logic {
/// INTERNAL ONLY
namespace detail {
/**
* INTERNAL ONLY
*
* \brief A type used only to uniquely identify the 'indeterminate'
* function/keyword.
*/
struct indeterminate_t
{
#if BOOST_WORKAROUND(__BORLANDC__, < 0x0600)
char dummy_; // BCB would use 8 bytes by default
#endif
};
} // end namespace detail
/**
* INTERNAL ONLY
* The type of the 'indeterminate' keyword. This has the same type as the
* function 'indeterminate' so that we can recognize when the keyword is
* used.
*/
typedef bool (*indeterminate_keyword_t)(tribool, detail::indeterminate_t);
/**
* \brief Keyword and test function for the indeterminate tribool value
*
* The \c indeterminate function has a dual role. It's first role is
* as a unary function that tells whether the tribool value is in the
* "indeterminate" state. It's second role is as a keyword
* representing the indeterminate (just like "true" and "false"
* represent the true and false states). If you do not like the name
* "indeterminate", and would prefer to use a different name, see the
* macro \c BOOST_TRIBOOL_THIRD_STATE.
*
* \returns <tt>x.value == tribool::indeterminate_value</tt>
* \throws nothrow
*/
BOOST_CONSTEXPR inline bool
indeterminate(tribool x,
detail::indeterminate_t dummy = detail::indeterminate_t()) BOOST_NOEXCEPT;
/**
* \brief A 3-state boolean type.
*
* 3-state boolean values are either true, false, or
* indeterminate.
*/
class tribool
{
#if defined( BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS )
private:
/// INTERNAL ONLY
struct dummy {
void nonnull() {};
};
typedef void (dummy::*safe_bool)();
#endif
public:
/**
* Construct a new 3-state boolean value with the value 'false'.
*
* \throws nothrow
*/
BOOST_CONSTEXPR tribool() BOOST_NOEXCEPT : value(false_value) {}
/**
* Construct a new 3-state boolean value with the given boolean
* value, which may be \c true or \c false.
*
* \throws nothrow
*/
BOOST_CONSTEXPR tribool(bool initial_value) BOOST_NOEXCEPT : value(initial_value? true_value : false_value) {}
/**
* Construct a new 3-state boolean value with an indeterminate value.
*
* \throws nothrow
*/
BOOST_CONSTEXPR tribool(indeterminate_keyword_t) BOOST_NOEXCEPT : value(indeterminate_value) {}
/**
* Use a 3-state boolean in a boolean context. Will evaluate true in a
* boolean context only when the 3-state boolean is definitely true.
*
* \returns true if the 3-state boolean is true, false otherwise
* \throws nothrow
*/
#if !defined( BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS )
BOOST_CONSTEXPR explicit operator bool () const BOOST_NOEXCEPT
{
return value == true_value;
}
#else
BOOST_CONSTEXPR operator safe_bool() const BOOST_NOEXCEPT
{
return value == true_value? &dummy::nonnull : 0;
}
#endif
/**
* The actual stored value in this 3-state boolean, which may be false, true,
* or indeterminate.
*/
enum value_t { false_value, true_value, indeterminate_value } value;
};
// Check if the given tribool has an indeterminate value. Also doubles as a
// keyword for the 'indeterminate' value
BOOST_CONSTEXPR inline bool indeterminate(tribool x, detail::indeterminate_t) BOOST_NOEXCEPT
{
return x.value == tribool::indeterminate_value;
}
/** @defgroup logical Logical operations
*/
//@{
/**
* \brief Computes the logical negation of a tribool
*
* \returns the logical negation of the tribool, according to the
* table:
* <table border=1>
* <tr>
* <th><center><code>!</code></center></th>
* <th/>
* </tr>
* <tr>
* <th><center>false</center></th>
* <td><center>true</center></td>
* </tr>
* <tr>
* <th><center>true</center></th>
* <td><center>false</center></td>
* </tr>
* <tr>
* <th><center>indeterminate</center></th>
* <td><center>indeterminate</center></td>
* </tr>
* </table>
* \throws nothrow
*/
BOOST_CONSTEXPR inline tribool operator!(tribool x) BOOST_NOEXCEPT
{
return x.value == tribool::false_value? tribool(true)
:x.value == tribool::true_value? tribool(false)
:tribool(indeterminate);
}
/**
* \brief Computes the logical conjunction of two tribools
*
* \returns the result of logically ANDing the two tribool values,
* according to the following table:
* <table border=1>
* <tr>
* <th><center><code>&amp;&amp;</code></center></th>
* <th><center>false</center></th>
* <th><center>true</center></th>
* <th><center>indeterminate</center></th>
* </tr>
* <tr>
* <th><center>false</center></th>
* <td><center>false</center></td>
* <td><center>false</center></td>
* <td><center>false</center></td>
* </tr>
* <tr>
* <th><center>true</center></th>
* <td><center>false</center></td>
* <td><center>true</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* <tr>
* <th><center>indeterminate</center></th>
* <td><center>false</center></td>
* <td><center>indeterminate</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* </table>
* \throws nothrow
*/
BOOST_CONSTEXPR inline tribool operator&&(tribool x, tribool y) BOOST_NOEXCEPT
{
return (static_cast<bool>(!x) || static_cast<bool>(!y))
? tribool(false)
: ((static_cast<bool>(x) && static_cast<bool>(y)) ? tribool(true) : indeterminate)
;
}
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator&&(tribool x, bool y) BOOST_NOEXCEPT
{ return y? x : tribool(false); }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator&&(bool x, tribool y) BOOST_NOEXCEPT
{ return x? y : tribool(false); }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator&&(indeterminate_keyword_t, tribool x) BOOST_NOEXCEPT
{ return !x? tribool(false) : tribool(indeterminate); }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator&&(tribool x, indeterminate_keyword_t) BOOST_NOEXCEPT
{ return !x? tribool(false) : tribool(indeterminate); }
/**
* \brief Computes the logical disjunction of two tribools
*
* \returns the result of logically ORing the two tribool values,
* according to the following table:
* <table border=1>
* <tr>
* <th><center><code>||</code></center></th>
* <th><center>false</center></th>
* <th><center>true</center></th>
* <th><center>indeterminate</center></th>
* </tr>
* <tr>
* <th><center>false</center></th>
* <td><center>false</center></td>
* <td><center>true</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* <tr>
* <th><center>true</center></th>
* <td><center>true</center></td>
* <td><center>true</center></td>
* <td><center>true</center></td>
* </tr>
* <tr>
* <th><center>indeterminate</center></th>
* <td><center>indeterminate</center></td>
* <td><center>true</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* </table>
* \throws nothrow
*/
BOOST_CONSTEXPR inline tribool operator||(tribool x, tribool y) BOOST_NOEXCEPT
{
return (static_cast<bool>(!x) && static_cast<bool>(!y))
? tribool(false)
: ((static_cast<bool>(x) || static_cast<bool>(y)) ? tribool(true) : tribool(indeterminate))
;
}
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator||(tribool x, bool y) BOOST_NOEXCEPT
{ return y? tribool(true) : x; }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator||(bool x, tribool y) BOOST_NOEXCEPT
{ return x? tribool(true) : y; }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator||(indeterminate_keyword_t, tribool x) BOOST_NOEXCEPT
{ return x? tribool(true) : tribool(indeterminate); }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator||(tribool x, indeterminate_keyword_t) BOOST_NOEXCEPT
{ return x? tribool(true) : tribool(indeterminate); }
//@}
/**
* \brief Compare tribools for equality
*
* \returns the result of comparing two tribool values, according to
* the following table:
* <table border=1>
* <tr>
* <th><center><code>==</code></center></th>
* <th><center>false</center></th>
* <th><center>true</center></th>
* <th><center>indeterminate</center></th>
* </tr>
* <tr>
* <th><center>false</center></th>
* <td><center>true</center></td>
* <td><center>false</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* <tr>
* <th><center>true</center></th>
* <td><center>false</center></td>
* <td><center>true</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* <tr>
* <th><center>indeterminate</center></th>
* <td><center>indeterminate</center></td>
* <td><center>indeterminate</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* </table>
* \throws nothrow
*/
BOOST_CONSTEXPR inline tribool operator==(tribool x, tribool y) BOOST_NOEXCEPT
{
return (indeterminate(x) || indeterminate(y))
? indeterminate
: ((x && y) || (!x && !y))
;
}
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator==(tribool x, bool y) BOOST_NOEXCEPT { return x == tribool(y); }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator==(bool x, tribool y) BOOST_NOEXCEPT { return tribool(x) == y; }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator==(indeterminate_keyword_t, tribool x) BOOST_NOEXCEPT
{ return tribool(indeterminate) == x; }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator==(tribool x, indeterminate_keyword_t) BOOST_NOEXCEPT
{ return tribool(indeterminate) == x; }
/**
* \brief Compare tribools for inequality
*
* \returns the result of comparing two tribool values for inequality,
* according to the following table:
* <table border=1>
* <tr>
* <th><center><code>!=</code></center></th>
* <th><center>false</center></th>
* <th><center>true</center></th>
* <th><center>indeterminate</center></th>
* </tr>
* <tr>
* <th><center>false</center></th>
* <td><center>false</center></td>
* <td><center>true</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* <tr>
* <th><center>true</center></th>
* <td><center>true</center></td>
* <td><center>false</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* <tr>
* <th><center>indeterminate</center></th>
* <td><center>indeterminate</center></td>
* <td><center>indeterminate</center></td>
* <td><center>indeterminate</center></td>
* </tr>
* </table>
* \throws nothrow
*/
BOOST_CONSTEXPR inline tribool operator!=(tribool x, tribool y) BOOST_NOEXCEPT
{
return (indeterminate(x) || indeterminate(y))
? indeterminate
: !((x && y) || (!x && !y))
;
}
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator!=(tribool x, bool y) BOOST_NOEXCEPT { return x != tribool(y); }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator!=(bool x, tribool y) BOOST_NOEXCEPT { return tribool(x) != y; }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator!=(indeterminate_keyword_t, tribool x) BOOST_NOEXCEPT
{ return tribool(indeterminate) != x; }
/**
* \overload
*/
BOOST_CONSTEXPR inline tribool operator!=(tribool x, indeterminate_keyword_t) BOOST_NOEXCEPT
{ return x != tribool(indeterminate); }
} } // end namespace boost::logic
// Pull tribool and indeterminate into namespace "boost"
namespace boost {
using logic::tribool;
using logic::indeterminate;
}
/**
* \brief Declare a new name for the third state of a tribool
*
* Use this macro to declare a new name for the third state of a
* tribool. This state can have any number of new names (in addition
* to \c indeterminate), all of which will be equivalent. The new name will be
* placed in the namespace in which the macro is expanded.
*
* Example:
* BOOST_TRIBOOL_THIRD_STATE(true_or_false)
*
* tribool x(true_or_false);
* // potentially set x
* if (true_or_false(x)) {
* // don't know what x is
* }
*/
#define BOOST_TRIBOOL_THIRD_STATE(Name) \
inline bool \
Name(boost::logic::tribool x, \
boost::logic::detail::indeterminate_t = \
boost::logic::detail::indeterminate_t()) \
{ return x.value == boost::logic::tribool::indeterminate_value; }
#endif // BOOST_LOGIC_TRIBOOL_HPP