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/* /////////////////////////////////////////////////////////////////////////
* File: stlsoft/util/operator_bool.hpp * * Purpose: A robust and portable operator bool generator class. * * Created: 5th November 2003 * Updated: 10th August 2009 * * Home: http://stlsoft.org/
* * Copyright (c) 2003-2009, Matthew Wilson and Synesis Software * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * - Redistributions of source code must retain the above copyright notice, this * list of conditions and the following disclaimer. * - Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * - Neither the name(s) of Matthew Wilson and Synesis Software nor the names of * any contributors may be used to endorse or promote products derived from * this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * * ////////////////////////////////////////////////////////////////////// */
/** \file stlsoft/util/operator_bool.hpp
* * \brief [C++ only] Definition of the stlsoft::operator_bool_generator * class template * (\ref group__library__utility "Utility" Library). */
#ifndef STLSOFT_INCL_STLSOFT_UTIL_HPP_OPERATOR_BOOL
#define STLSOFT_INCL_STLSOFT_UTIL_HPP_OPERATOR_BOOL
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
# define STLSOFT_VER_STLSOFT_UTIL_HPP_OPERATOR_BOOL_MAJOR 4
# define STLSOFT_VER_STLSOFT_UTIL_HPP_OPERATOR_BOOL_MINOR 0
# define STLSOFT_VER_STLSOFT_UTIL_HPP_OPERATOR_BOOL_REVISION 1
# define STLSOFT_VER_STLSOFT_UTIL_HPP_OPERATOR_BOOL_EDIT 36
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/* /////////////////////////////////////////////////////////////////////////
* Includes */
#ifndef STLSOFT_INCL_STLSOFT_H_STLSOFT
# include <stlsoft/stlsoft.h>
#endif /* !STLSOFT_INCL_STLSOFT_H_STLSOFT */
/* /////////////////////////////////////////////////////////////////////////
* Namespace */
#ifndef _STLSOFT_NO_NAMESPACE
namespace stlsoft { #endif /* _STLSOFT_NO_NAMESPACE */
/* /////////////////////////////////////////////////////////////////////////
* Macros */
/** \brief \def STLSOFT_DEFINE_OPERATOR_BOOL_TYPES(U, G, B)
* Defines the types for a type-safe boolean operator * * \ingroup group__library__utility * * \param U The Unique type. This is usually the \c class_type member type of the * class for which we are providing the boolean operator, but it could be any type. * \param G The Generator type. This is the type you use to qualify your call * to translate() inside the boolean operator * \param B The Boolean type. This is the type of the boolean operator */
# define STLSOFT_DEFINE_OPERATOR_BOOL_TYPES(U, G, B) \
\ typedef stlsoft_ns_qual(operator_bool_generator)<U>::class_type G; \ typedef G::return_type B
/** \brief \def STLSOFT_DEFINE_OPERATOR_BOOL_TYPES(U, G, B)
* Defines the types for a type-safe boolean operator, for use in templates * * \ingroup group__library__utility * * \param U The Unique type. This is usually the \c class_type member type of the * class for which we are providing the boolean operator, but it could be any type. * \param G The Generator type. This is the type you use to qualify your call * to translate() inside the boolean operator * \param B The Boolean type. This is the type of the boolean operator * * \note This is identical in form and purpose to STLSOFT_DEFINE_OPERATOR_BOOL_TYPES(), * except that it must be used for implementing operator boolean for templates */
#if defined(STLSOFT_COMPILER_IS_BORLAND) || \
( defined(STLSOFT_COMPILER_IS_MSVC) && \ _MSC_VER < 1300)
# define STLSOFT_DEFINE_OPERATOR_BOOL_TYPES_T(U, G, B) \
\ STLSOFT_DEFINE_OPERATOR_BOOL_TYPES(U, G, B)
#else /* ? compiler */
# define STLSOFT_DEFINE_OPERATOR_BOOL_TYPES_T(U, G, B) \
\ typedef ss_typename_param_k stlsoft_ns_qual(operator_bool_generator)<U>::class_type G; \ typedef ss_typename_param_k G::return_type B
#endif /* compiler */
/* /////////////////////////////////////////////////////////////////////////
* Classes */
/** \brief Template which provides the types and conversion operations for safe and
* highly-portable "<code>operator bool() const</code>". * * \ingroup group__library__utility */ template <ss_typename_param_k T> struct operator_bool_generator { public: typedef operator_bool_generator<T> class_type;
#ifdef STLSOFT_CF_OPERATOR_BOOL_AS_OPERATOR_POINTER_TO_MEMBER_SUPPORT
typedef int class_type::*return_type;
/// Returns the value representing the true condition
static return_type true_value() { return &class_type::i; }
private: int i; public: #else
typedef class_type const* return_type;
/// Returns the value representing the true condition
static return_type true_value() { class_type t; void *p = static_cast<void*>(&t);
return static_cast<return_type>(p); } #endif // STLSOFT_CF_OPERATOR_BOOL_AS_OPERATOR_POINTER_TO_MEMBER_SUPPORT
/// Returns the value representing the false condition
static return_type false_value() { return static_cast<return_type>(0); }
/// Does the ternary operator for you
#ifdef STLSOFT_CF_MEMBER_TEMPLATE_FUNCTION_SUPPORT
template <ss_typename_param_k U> static return_type translate(U b) #else /* ? STLSOFT_CF_MEMBER_TEMPLATE_FUNCTION_SUPPORT */
static return_type translate(ss_bool_t b) #endif // STLSOFT_CF_MEMBER_TEMPLATE_FUNCTION_SUPPORT
{ return b ? true_value() : false_value(); }
private: void operator delete(void*); };
/* ////////////////////////////////////////////////////////////////////// */
#ifndef _STLSOFT_NO_NAMESPACE
} // namespace stlsoft
#endif /* _STLSOFT_NO_NAMESPACE */
/* ////////////////////////////////////////////////////////////////////// */
#endif /* !STLSOFT_INCL_STLSOFT_UTIL_HPP_OPERATOR_BOOL */
/* ///////////////////////////// end of file //////////////////////////// */
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