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220 lines
7.8 KiB
220 lines
7.8 KiB
/* /////////////////////////////////////////////////////////////////////////
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* File: stlsoft/conversion/literal_cast.hpp
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*
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* Purpose: Compile-time checking for literal conversions.
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*
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* Created: 5th September 2003
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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) 2003-2009, 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/literal_cast.hpp
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*
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* \brief [C++ only] Definition of the stlsoft::literal_cast cast class
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* (\ref group__library__conversion "Conversion" Library).
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*/
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#ifndef STLSOFT_INCL_STLSOFT_CONVERSION_HPP_LITERAL_CAST
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#define STLSOFT_INCL_STLSOFT_CONVERSION_HPP_LITERAL_CAST
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#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
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# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_LITERAL_CAST_MAJOR 4
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# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_LITERAL_CAST_MINOR 0
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# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_LITERAL_CAST_REVISION 4
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# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_LITERAL_CAST_EDIT 44
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#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
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/* /////////////////////////////////////////////////////////////////////////
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* Auto-generation and compatibility
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*/
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/*
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[<[STLSOFT-AUTO:NO-UNITTEST]>]
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*/
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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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#ifndef STLSOFT_INCL_STLSOFT_UTIL_H_LIMIT_TRAITS
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# include <stlsoft/util/limit_traits.h>
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#endif /* !STLSOFT_INCL_STLSOFT_UTIL_H_LIMIT_TRAITS */
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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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#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
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# ifdef STLSOFT_CF_64BIT_INT_SUPPORT
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typedef ss_sint64_t literal_cast_int_t;
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typedef ss_uint64_t invalid_int_t;
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# else /* ? STLSOFT_CF_64BIT_INT_SUPPORT */
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typedef ss_sint32_t literal_cast_int_t;
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typedef ss_uint32_t invalid_int_t;
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# endif /* STLSOFT_CF_64BIT_INT_SUPPORT */
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#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
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#if 0
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template< ss_typename_param_k T
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, literal_cast_int_t V
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>
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inline T literal_cast()
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{
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#if defined(STLSOFT_CF_MEMBER_CONSTANT_SUPPORT)
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/* If member constants are supported, we can do compile-time assertions */
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const int __literal_cast_value_too_large__ = V <= limit_traits<T>::maximum_value;
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const int __literal_cast_value_too_small__ = V >= limit_traits<T>::minimum_value;
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STLSOFT_STATIC_ASSERT(__literal_cast_value_too_large__);
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STLSOFT_STATIC_ASSERT(__literal_cast_value_too_small__);
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#else /* ? STLSOFT_CF_MEMBER_CONSTANT_SUPPORT */
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/* If not, then we are restricted to runtime assertions */
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const int __literal_cast_value_too_large__ = V <= limit_traits<T>::maximum();
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const int __literal_cast_value_too_small__ = V >= limit_traits<T>::minimum();
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STLSOFT_MESSAGE_ASSERT("Literal cast value is too large", __literal_cast_value_too_large__);
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STLSOFT_MESSAGE_ASSERT("Literal cast value is too small", __literal_cast_value_too_small__);
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#endif /* STLSOFT_CF_MEMBER_CONSTANT_SUPPORT */
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return T(V);
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}
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#else /* ? 0 */
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/** \brief Provides compile-time validation for casts of literal values.
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*
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* \ingroup group__library__conversion
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*
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* \param T The type to cast to
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* \param V The literal value to be cast
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*
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\code
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short s1 = stlsoft::literal_cast<short, 10>(); // Ok: 10 fits into short
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short s2 = stlsoft::literal_cast<short, 1000000000>(); // Compile error: value too large for short
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\endcode
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*
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* \note Thanks to Kevlin Henney (http://www.curbralan.com/) for insights
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* into the solution.
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*/
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template< ss_typename_param_k T
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, literal_cast_int_t V
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>
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class literal_cast
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{
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public:
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operator T () const
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{
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#if defined(STLSOFT_CF_MEMBER_CONSTANT_SUPPORT)
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/* If member constants are supported, we can do compile-time assertions */
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const int __literal_cast_value_too_large__ = V <= limit_traits<T>::maximum_value;
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const int __literal_cast_value_too_small__ = V >= limit_traits<T>::minimum_value;
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STLSOFT_STATIC_ASSERT(__literal_cast_value_too_large__);
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STLSOFT_STATIC_ASSERT(__literal_cast_value_too_small__);
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#else /* ? STLSOFT_CF_MEMBER_CONSTANT_SUPPORT */
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/* If not, then we are restricted to runtime assertions */
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const int __literal_cast_value_too_large__ = V <= limit_traits<T>::maximum();
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const int __literal_cast_value_too_small__ = V >= limit_traits<T>::minimum();
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STLSOFT_MESSAGE_ASSERT("Literal cast value is too large", __literal_cast_value_too_large__);
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STLSOFT_MESSAGE_ASSERT("Literal cast value is too small", __literal_cast_value_too_small__);
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#endif /* STLSOFT_CF_MEMBER_CONSTANT_SUPPORT */
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return T(V);
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}
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};
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#ifdef STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT
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/** Partial specialisation to
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*/
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template<literal_cast_int_t V>
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class literal_cast<invalid_int_t, V>
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{
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public:
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# if 0
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literal_cast()
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{
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const int STLSOFT_LITERAL_CAST_INVALID_TYPE_WARNING = 0;
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STLSOFT_STATIC_ASSERT(STLSOFT_LITERAL_CAST_INVALID_TYPE_WARNING);
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}
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# endif /* 0 */
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private:
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operator invalid_int_t () const
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{
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const int __literal_cast_cannot_cast_to_largest_unsigned_integer_type__ = 0;
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STLSOFT_STATIC_ASSERT(__literal_cast_cannot_cast_to_largest_unsigned_integer_type__);
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return 0;
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}
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# if defined(STLSOFT_COMPILER_IS_GCC)
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public: static void f() {}
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# endif /* compiler */
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};
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#endif /* STLSOFT_CF_TEMPLATE_PARTIAL_SPECIALISATION_SUPPORT */
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#endif /* 0 */
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////////////////////////////////////////////////////////////////////////////
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// Unit-testing
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#ifdef STLSOFT_UNITTEST
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# include "./unittest/literal_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_LITERAL_CAST */
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/* ///////////////////////////// end of file //////////////////////////// */
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