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192 lines
7.6 KiB
192 lines
7.6 KiB
/* /////////////////////////////////////////////////////////////////////////
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* File: stlsoft/conversion/sap_cast.hpp
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*
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* Purpose: A cast operator function that casts between non void pointers of
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* the same cv-qualification.
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*
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* Created: 25th February 2004
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* Updated: 10th August 2009
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*
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* Home: http://stlsoft.org/
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*
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* Copyright (c) 2004-2009, Matthew Wilson and Synesis Software
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* - Neither the name(s) of Matthew Wilson and Synesis Software nor the names of
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* any contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* ////////////////////////////////////////////////////////////////////// */
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/** \file stlsoft/conversion/sap_cast.hpp
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*
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* \brief [C++ only] Definition of the stlsoft::sap_cast cast function
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* (\ref group__library__conversion "Conversion" Library).
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*/
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#ifndef STLSOFT_INCL_STLSOFT_CONVERSION_HPP_SAP_CAST
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#define STLSOFT_INCL_STLSOFT_CONVERSION_HPP_SAP_CAST
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#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
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# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_SAP_CAST_MAJOR 4
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# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_SAP_CAST_MINOR 0
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# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_SAP_CAST_REVISION 2
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# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_SAP_CAST_EDIT 46
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#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
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/* /////////////////////////////////////////////////////////////////////////
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* Includes
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*/
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#ifndef STLSOFT_INCL_STLSOFT_H_STLSOFT
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# include <stlsoft/stlsoft.h>
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#endif /* !STLSOFT_INCL_STLSOFT_H_STLSOFT */
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#if ( defined(STLSOFT_COMPILER_IS_GCC) && \
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__GNUC__ < 3) || \
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( defined(STLSOFT_COMPILER_IS_MSVC) && \
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_MSC_VER < 1200) || \
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defined(STLSOFT_COMPILER_IS_WATCOM)
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# define STLSOFT_NO_SAP_CAST
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#endif /* compiler */
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#if !defined(STLSOFT_NO_SAP_CAST) && \
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defined(STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT)
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# ifndef STLSOFT_INCL_STLSOFT_UTIL_HPP_CONSTRAINTS
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# include <stlsoft/util/constraints.hpp>
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# endif /* !STLSOFT_INCL_STLSOFT_UTIL_HPP_CONSTRAINTS */
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# ifndef STLSOFT_INCL_STLSOFT_META_HPP_BASE_TYPE_TRAITS
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# include <stlsoft/meta/base_type_traits.hpp>
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# endif /* !STLSOFT_INCL_STLSOFT_META_HPP_BASE_TYPE_TRAITS */
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# ifndef STLSOFT_INCL_STLSOFT_META_HPP_SELECT_FIRST_TYPE_IF
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# include <stlsoft/meta/select_first_type_if.hpp>
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# endif /* !STLSOFT_INCL_STLSOFT_META_HPP_SELECT_FIRST_TYPE_IF */
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#endif /* !STLSOFT_NO_SAP_CAST && STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
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/* /////////////////////////////////////////////////////////////////////////
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* Namespace
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*/
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#ifndef _STLSOFT_NO_NAMESPACE
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namespace stlsoft
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{
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#endif /* _STLSOFT_NO_NAMESPACE */
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/* /////////////////////////////////////////////////////////////////////////
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* Functions
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*/
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/** \brief A cast operator function that casts between non void pointers of
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* the same cv-qualification.
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*
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* \ingroup group__library__conversion
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*
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* The implementation of the operator uses compile-time enforcement of
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* various constraints to ensure that:
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*
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* - the FROM and TO types are both pointers
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* - no cv-qualifiers are stripped from the FROM type
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*
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* For example, this cast is allowed:
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\code
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int* pi = . . .;
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short const* ps = stlsoft::sap_cast<short const*>(pi);
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\endcode
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*
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* but this cast is not:
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\code
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int const* pi = . . .;
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short* ps = stlsoft::sap_cast<short*>(pi);
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\endcode
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*
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* \param from The pointer to cast from.
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*
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* \remarks The cast operator was inspired by an item in the
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* Sutter/Alexandrescu coding standards book, and its names stands for
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* Sutter-Alexandrescu-Pointer cast. The acronym is overloaded, since one
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* might also be said to be a sap if one made injudicious use of the cast,
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* due to its inherent dangers.
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*/
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#if defined(STLSOFT_NO_SAP_CAST)
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# define sap_cast reinterpret_cast
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#else /* ? STLSOFT_NO_SAP_CAST */
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template< ss_typename_param_k TO
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, ss_typename_param_k FROM
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>
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inline TO sap_cast(FROM from)
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{
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# if defined(STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT) && \
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( !defined(STLSOFT_COMPILER_IS_BORLAND))
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// Both types must be pointer types
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STLSOFT_STATIC_ASSERT(0 != base_type_traits<FROM>::is_pointer);
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STLSOFT_STATIC_ASSERT(0 != base_type_traits<TO>::is_pointer);
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typedef ss_typename_type_k base_type_traits<FROM>::base_type from_base_type;
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typedef ss_typename_type_k base_type_traits<TO>::base_type to_base_type;
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// The intermediate type might be void *, void const*, void volatile * or
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// void const volatile *
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typedef ss_typename_type_k select_first_type_if<void const*
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, void*
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, base_type_traits<FROM>::is_const
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>::type non_volatile_type;
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typedef ss_typename_type_k select_first_type_if<void const volatile*
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, void volatile*
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, base_type_traits<FROM>::is_const
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>::type volatile_type;
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typedef ss_typename_type_k select_first_type_if<volatile_type
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, non_volatile_type
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, base_type_traits<FROM>::is_volatile
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>::type pointer_type;
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// "static_cast" to void (const) (volatile) *
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pointer_type pv = from;
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# else /* STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
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void const volatile *p1 = from;
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void *pv = const_cast<void*>(p1);
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# endif /* STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
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// static_cast to destination type
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return static_cast<TO>(pv);
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}
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#endif /* STLSOFT_NO_SAP_CAST */
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////////////////////////////////////////////////////////////////////////////
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// Unit-testing
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#ifdef STLSOFT_UNITTEST
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# include "./unittest/sap_cast_unittest_.h"
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#endif /* STLSOFT_UNITTEST */
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/* ////////////////////////////////////////////////////////////////////// */
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#ifndef _STLSOFT_NO_NAMESPACE
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} // namespace stlsoft
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#endif /* _STLSOFT_NO_NAMESPACE */
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/* ////////////////////////////////////////////////////////////////////// */
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#endif /* !STLSOFT_INCL_STLSOFT_CONVERSION_HPP_SAP_CAST */
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/* ///////////////////////////// end of file //////////////////////////// */
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