ext-boost/boost/core/explicit_operator_bool.hpp
2014-12-07 23:50:51 +01:00

155 lines
5 KiB
C++

/*
* Copyright Andrey Semashev 2007 - 2013.
* Distributed under 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)
*/
/*!
* \file explicit_operator_bool.hpp
* \author Andrey Semashev
* \date 08.03.2009
*
* This header defines a compatibility macro that implements an unspecified
* \c bool operator idiom, which is superseded with explicit conversion operators in
* C++11.
*/
#ifndef BOOST_CORE_EXPLICIT_OPERATOR_BOOL_HPP
#define BOOST_CORE_EXPLICIT_OPERATOR_BOOL_HPP
#include <boost/config.hpp>
#ifdef BOOST_HAS_PRAGMA_ONCE
#pragma once
#endif
#if !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
/*!
* \brief The macro defines an explicit operator of conversion to \c bool
*
* The macro should be used inside the definition of a class that has to
* support the conversion. The class should also implement <tt>operator!</tt>,
* in terms of which the conversion operator will be implemented.
*/
#define BOOST_EXPLICIT_OPERATOR_BOOL()\
BOOST_FORCEINLINE explicit operator bool () const\
{\
return !this->operator! ();\
}
/*!
* \brief The macro defines a noexcept explicit operator of conversion to \c bool
*
* The macro should be used inside the definition of a class that has to
* support the conversion. The class should also implement <tt>operator!</tt>,
* in terms of which the conversion operator will be implemented.
*/
#define BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()\
BOOST_FORCEINLINE explicit operator bool () const BOOST_NOEXCEPT\
{\
return !this->operator! ();\
}
/*!
* \brief The macro defines a constexpr explicit operator of conversion to \c bool
*
* The macro should be used inside the definition of a class that has to
* support the conversion. The class should also implement <tt>operator!</tt>,
* in terms of which the conversion operator will be implemented.
*/
#define BOOST_CONSTEXPR_EXPLICIT_OPERATOR_BOOL()\
BOOST_FORCEINLINE BOOST_CONSTEXPR explicit operator bool () const BOOST_NOEXCEPT\
{\
return !this->operator! ();\
}
#else // !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
#if (defined(__SUNPRO_CC) && (__SUNPRO_CC <= 0x530)) && !defined(BOOST_NO_COMPILER_CONFIG)
// Sun C++ 5.3 can't handle the safe_bool idiom, so don't use it
#define BOOST_NO_UNSPECIFIED_BOOL
#endif // (defined(__SUNPRO_CC) && (__SUNPRO_CC <= 0x530)) && !defined(BOOST_NO_COMPILER_CONFIG)
#if !defined(BOOST_NO_UNSPECIFIED_BOOL)
namespace boost {
namespace detail {
#if !defined(_MSC_VER) && !defined(__IBMCPP__)
struct unspecified_bool
{
// NOTE TO THE USER: If you see this in error messages then you tried
// to apply an unsupported operator on the object that supports
// explicit conversion to bool.
struct OPERATORS_NOT_ALLOWED;
static void true_value(OPERATORS_NOT_ALLOWED*) {}
};
typedef void (*unspecified_bool_type)(unspecified_bool::OPERATORS_NOT_ALLOWED*);
#else
// MSVC and VACPP are too eager to convert pointer to function to void* even though they shouldn't
struct unspecified_bool
{
// NOTE TO THE USER: If you see this in error messages then you tried
// to apply an unsupported operator on the object that supports
// explicit conversion to bool.
struct OPERATORS_NOT_ALLOWED;
void true_value(OPERATORS_NOT_ALLOWED*) {}
};
typedef void (unspecified_bool::*unspecified_bool_type)(unspecified_bool::OPERATORS_NOT_ALLOWED*);
#endif
} // namespace detail
} // namespace boost
#define BOOST_EXPLICIT_OPERATOR_BOOL()\
BOOST_FORCEINLINE operator boost::detail::unspecified_bool_type () const\
{\
return (!this->operator! () ? &boost::detail::unspecified_bool::true_value : (boost::detail::unspecified_bool_type)0);\
}
#define BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()\
BOOST_FORCEINLINE operator boost::detail::unspecified_bool_type () const BOOST_NOEXCEPT\
{\
return (!this->operator! () ? &boost::detail::unspecified_bool::true_value : (boost::detail::unspecified_bool_type)0);\
}
#define BOOST_CONSTEXPR_EXPLICIT_OPERATOR_BOOL()\
BOOST_FORCEINLINE BOOST_CONSTEXPR operator boost::detail::unspecified_bool_type () const BOOST_NOEXCEPT\
{\
return (!this->operator! () ? &boost::detail::unspecified_bool::true_value : (boost::detail::unspecified_bool_type)0);\
}
#else // !defined(BOOST_NO_UNSPECIFIED_BOOL)
#define BOOST_EXPLICIT_OPERATOR_BOOL()\
BOOST_FORCEINLINE operator bool () const\
{\
return !this->operator! ();\
}
#define BOOST_EXPLICIT_OPERATOR_BOOL_NOEXCEPT()\
BOOST_FORCEINLINE operator bool () const BOOST_NOEXCEPT\
{\
return !this->operator! ();\
}
#define BOOST_CONSTEXPR_EXPLICIT_OPERATOR_BOOL()\
BOOST_FORCEINLINE BOOST_CONSTEXPR operator bool () const BOOST_NOEXCEPT\
{\
return !this->operator! ();\
}
#endif // !defined(BOOST_NO_UNSPECIFIED_BOOL)
#endif // !defined(BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS)
#endif // BOOST_CORE_EXPLICIT_OPERATOR_BOOL_HPP