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/* /////////////////////////////////////////////////////////////////////////
* File: stlsoft/conversion/sap_cast.hpp * * Purpose: A cast operator function that casts between non void pointers of * the same cv-qualification. * * Created: 25th February 2004 * Updated: 10th August 2009 * * Home: http://stlsoft.org/
* * Copyright (c) 2004-2009, 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/conversion/sap_cast.hpp
* * \brief [C++ only] Definition of the stlsoft::sap_cast cast function * (\ref group__library__conversion "Conversion" Library). */
#ifndef STLSOFT_INCL_STLSOFT_CONVERSION_HPP_SAP_CAST
#define STLSOFT_INCL_STLSOFT_CONVERSION_HPP_SAP_CAST
#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_SAP_CAST_MAJOR 4
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_SAP_CAST_MINOR 0
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_SAP_CAST_REVISION 2
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_SAP_CAST_EDIT 46
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
/* /////////////////////////////////////////////////////////////////////////
* Includes */
#ifndef STLSOFT_INCL_STLSOFT_H_STLSOFT
# include <stlsoft/stlsoft.h>
#endif /* !STLSOFT_INCL_STLSOFT_H_STLSOFT */
#if ( defined(STLSOFT_COMPILER_IS_GCC) && \
__GNUC__ < 3) || \ ( defined(STLSOFT_COMPILER_IS_MSVC) && \ _MSC_VER < 1200) || \ defined(STLSOFT_COMPILER_IS_WATCOM) # define STLSOFT_NO_SAP_CAST
#endif /* compiler */
#if !defined(STLSOFT_NO_SAP_CAST) && \
defined(STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT) # ifndef STLSOFT_INCL_STLSOFT_UTIL_HPP_CONSTRAINTS
# include <stlsoft/util/constraints.hpp>
# endif /* !STLSOFT_INCL_STLSOFT_UTIL_HPP_CONSTRAINTS */
# ifndef STLSOFT_INCL_STLSOFT_META_HPP_BASE_TYPE_TRAITS
# include <stlsoft/meta/base_type_traits.hpp>
# endif /* !STLSOFT_INCL_STLSOFT_META_HPP_BASE_TYPE_TRAITS */
# ifndef STLSOFT_INCL_STLSOFT_META_HPP_SELECT_FIRST_TYPE_IF
# include <stlsoft/meta/select_first_type_if.hpp>
# endif /* !STLSOFT_INCL_STLSOFT_META_HPP_SELECT_FIRST_TYPE_IF */
#endif /* !STLSOFT_NO_SAP_CAST && STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
/* /////////////////////////////////////////////////////////////////////////
* Namespace */
#ifndef _STLSOFT_NO_NAMESPACE
namespace stlsoft { #endif /* _STLSOFT_NO_NAMESPACE */
/* /////////////////////////////////////////////////////////////////////////
* Functions */
/** \brief A cast operator function that casts between non void pointers of
* the same cv-qualification. * * \ingroup group__library__conversion * * The implementation of the operator uses compile-time enforcement of * various constraints to ensure that: * * - the FROM and TO types are both pointers * - no cv-qualifiers are stripped from the FROM type * * For example, this cast is allowed: \code int* pi = . . .; short const* ps = stlsoft::sap_cast<short const*>(pi); \endcode * * but this cast is not: \code int const* pi = . . .; short* ps = stlsoft::sap_cast<short*>(pi); \endcode * * \param from The pointer to cast from. * * \remarks The cast operator was inspired by an item in the * Sutter/Alexandrescu coding standards book, and its names stands for * Sutter-Alexandrescu-Pointer cast. The acronym is overloaded, since one * might also be said to be a sap if one made injudicious use of the cast, * due to its inherent dangers. */ #if defined(STLSOFT_NO_SAP_CAST)
# define sap_cast reinterpret_cast
#else /* ? STLSOFT_NO_SAP_CAST */
template< ss_typename_param_k TO , ss_typename_param_k FROM > inline TO sap_cast(FROM from) { # if defined(STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT) && \
( !defined(STLSOFT_COMPILER_IS_BORLAND)) // Both types must be pointer types
STLSOFT_STATIC_ASSERT(0 != base_type_traits<FROM>::is_pointer); STLSOFT_STATIC_ASSERT(0 != base_type_traits<TO>::is_pointer);
typedef ss_typename_type_k base_type_traits<FROM>::base_type from_base_type; typedef ss_typename_type_k base_type_traits<TO>::base_type to_base_type;
// The intermediate type might be void *, void const*, void volatile * or
// void const volatile *
typedef ss_typename_type_k select_first_type_if<void const* , void* , base_type_traits<FROM>::is_const >::type non_volatile_type; typedef ss_typename_type_k select_first_type_if<void const volatile* , void volatile* , base_type_traits<FROM>::is_const >::type volatile_type; typedef ss_typename_type_k select_first_type_if<volatile_type , non_volatile_type , base_type_traits<FROM>::is_volatile >::type pointer_type;
// "static_cast" to void (const) (volatile) *
pointer_type pv = from; # else /* STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
void const volatile *p1 = from; void *pv = const_cast<void*>(p1); # endif /* STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
// static_cast to destination type
return static_cast<TO>(pv); } #endif /* STLSOFT_NO_SAP_CAST */
////////////////////////////////////////////////////////////////////////////
// Unit-testing
#ifdef STLSOFT_UNITTEST
# include "./unittest/sap_cast_unittest_.h"
#endif /* STLSOFT_UNITTEST */
/* ////////////////////////////////////////////////////////////////////// */
#ifndef _STLSOFT_NO_NAMESPACE
} // namespace stlsoft
#endif /* _STLSOFT_NO_NAMESPACE */
/* ////////////////////////////////////////////////////////////////////// */
#endif /* !STLSOFT_INCL_STLSOFT_CONVERSION_HPP_SAP_CAST */
/* ///////////////////////////// end of file //////////////////////////// */
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