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Diff: tvmet/TypePromotion.h
- Revision:
- 1:6799c07fe510
--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/tvmet/TypePromotion.h Wed Nov 07 14:37:35 2012 +0000 @@ -0,0 +1,232 @@ +/* + * Tiny Vector Matrix Library + * Dense Vector Matrix Libary of Tiny size using Expression Templates + * + * Copyright (C) 2001 - 2007 Olaf Petzold <opetzold@users.sourceforge.net> + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public + * License as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public + * License along with this library; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * $Id: TypePromotion.h,v 1.10 2007-06-23 15:58:58 opetzold Exp $ + */ + +#ifndef TVMET_TYPE_PROMOTION_H +#define TVMET_TYPE_PROMOTION_H + +namespace tvmet { + + +/** + * \class PrecisionTraits TypePromotion.h "tvmet/TypePromotion.h" + * \brief Declaring ranks of types to avoid specializing + * + * All possible promoted types. For example, bool=1, int=2, float=3, double=4, + * etc. We can use a traits class to map from a type such as float onto its + * "precision rank". We will promote to whichever type has a higher + * "precision rank". f there is no "precision rank" for a type, we'll + * promote to whichever type requires more storage space + * (and hopefully more precision). + */ +template<class T> +struct PrecisionTraits { + enum { + rank = 0, /**< the rank of type. */ + known = 0 /**< true, if the rank is specialized = known. */ + }; +}; + + +#define TVMET_PRECISION(T,R) \ +template<> \ +struct PrecisionTraits< T > { \ + enum { \ + rank = R, \ + known = 1 \ + }; \ +}; + + +/* + * pod types + */ +TVMET_PRECISION(int, 100) +TVMET_PRECISION(unsigned int, 200) +TVMET_PRECISION(long, 300) +TVMET_PRECISION(unsigned long, 400) + +#if defined(TVMET_HAVE_LONG_LONG) +TVMET_PRECISION(long long, 500) +TVMET_PRECISION(unsigned long long, 600) +#endif // defined(TVMET_HAVE_LONG_LONG) + +TVMET_PRECISION(float, 700) +TVMET_PRECISION(double, 800) + +#if defined(TVMET_HAVE_LONG_DOUBLE) +TVMET_PRECISION(long double, 900) +#endif // defined(TVMET_HAVE_LONG_DOUBLE) + + +/* + * complex types + */ +#if defined(TVMET_HAVE_COMPLEX) +TVMET_PRECISION(std::complex<int>, 1000) +TVMET_PRECISION(std::complex<unsigned int>, 1100) +TVMET_PRECISION(std::complex<long>, 1200) +TVMET_PRECISION(std::complex<unsigned long>, 1300) + +#if defined(TVMET_HAVE_LONG_LONG) +TVMET_PRECISION(std::complex<long long>, 1400) +TVMET_PRECISION(std::complex<unsigned long long>, 1500) +#endif // defined(TVMET_HAVE_LONG_LONG) + +TVMET_PRECISION(std::complex<float>, 1600) +TVMET_PRECISION(std::complex<double>, 1700) + +#if defined(TVMET_HAVE_LONG_DOUBLE) +TVMET_PRECISION(std::complex<long double>, 1800) +#endif // defined(TVMET_HAVE_LONG_DOUBLE) + +#endif // defined(TVMET_HAVE_COMPLEX) + + +/** \class PrecisionTraits<int> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits<unsigned int> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits<long> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits<unsigned long> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits<long long> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits<unsigned long long> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits<float> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits<double> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits<long double> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits< std::complex<int> > TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits< std::complex<unsigned int> > TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits< std::complex<long> > TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits< std::complex<unsigned long> > TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits< std::complex<long long> > TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits< std::complex<unsigned long long> > TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits< std::complex<float> > TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits< std::complex<double> > TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class PrecisionTraits< std::complex<long double> > TypePromotion.h "tvmet/TypePromotion.h" */ + +#undef TVMET_PRECISION + + +/** + * \class AutopromoteTraits TypePromotion.h "tvmet/TypePromotion.h" + * \brief The promoted types traits. + */ +template<class T> +struct AutopromoteTraits { + typedef T value_type; +}; + + +/* + * Defines a macro for specializing/defining + * the promotion traits. bool, char, unsigned char, short int, etc. will + * be autopromote to int, as in C and C++. + */ +#define TVMET_AUTOPROMOTE(T1,T2) \ +template<> \ +struct AutopromoteTraits<T1> { \ + typedef T2 value_type; \ +}; + +TVMET_AUTOPROMOTE(bool, int) +TVMET_AUTOPROMOTE(char, int) +TVMET_AUTOPROMOTE(unsigned char, int) +TVMET_AUTOPROMOTE(short int, int) +TVMET_AUTOPROMOTE(short unsigned int, unsigned int) + +/** \class AutopromoteTraits<bool> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class AutopromoteTraits<char> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class AutopromoteTraits<unsigned char> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class AutopromoteTraits<short int> TypePromotion.h "tvmet/TypePromotion.h" */ +/** \class AutopromoteTraits<short unsigned int> TypePromotion.h "tvmet/TypePromotion.h" */ + +#undef TVMET_AUTOPROMOTE + + +/** + * \class promoteTo TypePromotion.h "tvmet/TypePromotion.h" + * \brief Promote to T1. + */ +template<class T1, class T2, int promoteToT1> +struct promoteTo { + typedef T1 value_type; +}; + + +/** + * \class promoteTo<T1,T2,0> TypePromotion.h "tvmet/TypePromotion.h" + * \brief Promote to T2 + */ +template<class T1, class T2> +struct promoteTo<T1,T2,0> { + typedef T2 value_type; +}; + + +/** + * \class PromoteTraits TypePromotion.h "tvmet/TypePromotion.h" + * \brief Promote type traits + */ +template<class T1org, class T2org> +class PromoteTraits { + // Handle promotion of small integers to int/unsigned int + typedef typename AutopromoteTraits<T1org>::value_type T1; + typedef typename AutopromoteTraits<T2org>::value_type T2; + + enum { + // True if T1 is higher ranked + T1IsBetter = int(PrecisionTraits<T1>::rank) > int(PrecisionTraits<T2>::rank), + + // True if we know ranks for both T1 and T2 + knowBothRanks = PrecisionTraits<T1>::known && PrecisionTraits<T2>::known, + + // True if we know T1 but not T2 + knowT1butNotT2 = PrecisionTraits<T1>::known && !(PrecisionTraits<T2>::known), + + // True if we know T2 but not T1 + knowT2butNotT1 = PrecisionTraits<T2>::known && !(PrecisionTraits<T1>::known), + + // True if T1 is bigger than T2 + T1IsLarger = sizeof(T1) >= sizeof(T2), + + // We know T1 but not T2: true + // We know T2 but not T1: false + // Otherwise, if T1 is bigger than T2: true + defaultPromotion = knowT1butNotT2 ? false : (knowT2butNotT1 ? true : T1IsLarger), + + // If we have both ranks, then use them. + // If we have only one rank, then use the unknown type. + // If we have neither rank, then promote to the larger type. + promoteToT1 = (knowBothRanks ? T1IsBetter : defaultPromotion) ? 1 : 0 + }; + + public: + typedef typename promoteTo<T1,T2,promoteToT1>::value_type value_type; +}; + + +} // namespace tvmet + +#endif // TVMET_TYPE_PROMOTION_H + +// Local Variables: +// mode:C++ +// tab-width:8 +// End: