1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // Copyright (C) 2008-2009 Gael Guennebaud <gael.guennebaud (at) inria.fr> 5 // Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1 (at) gmail.com> 6 // 7 // This Source Code Form is subject to the terms of the Mozilla 8 // Public License v. 2.0. If a copy of the MPL was not distributed 9 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/. 10 11 #ifndef EIGEN_META_H 12 #define EIGEN_META_H 13 14 namespace Eigen { 15 16 namespace internal { 17 18 /** \internal 19 * \file Meta.h 20 * This file contains generic metaprogramming classes which are not specifically related to Eigen. 21 * \note In case you wonder, yes we're aware that Boost already provides all these features, 22 * we however don't want to add a dependency to Boost. 23 */ 24 25 struct true_type { enum { value = 1 }; }; 26 struct false_type { enum { value = 0 }; }; 27 28 template<bool Condition, typename Then, typename Else> 29 struct conditional { typedef Then type; }; 30 31 template<typename Then, typename Else> 32 struct conditional <false, Then, Else> { typedef Else type; }; 33 34 template<typename T, typename U> struct is_same { enum { value = 0 }; }; 35 template<typename T> struct is_same<T,T> { enum { value = 1 }; }; 36 37 template<typename T> struct remove_reference { typedef T type; }; 38 template<typename T> struct remove_reference<T&> { typedef T type; }; 39 40 template<typename T> struct remove_pointer { typedef T type; }; 41 template<typename T> struct remove_pointer<T*> { typedef T type; }; 42 template<typename T> struct remove_pointer<T*const> { typedef T type; }; 43 44 template <class T> struct remove_const { typedef T type; }; 45 template <class T> struct remove_const<const T> { typedef T type; }; 46 template <class T> struct remove_const<const T[]> { typedef T type[]; }; 47 template <class T, unsigned int Size> struct remove_const<const T[Size]> { typedef T type[Size]; }; 48 49 template<typename T> struct remove_all { typedef T type; }; 50 template<typename T> struct remove_all<const T> { typedef typename remove_all<T>::type type; }; 51 template<typename T> struct remove_all<T const&> { typedef typename remove_all<T>::type type; }; 52 template<typename T> struct remove_all<T&> { typedef typename remove_all<T>::type type; }; 53 template<typename T> struct remove_all<T const*> { typedef typename remove_all<T>::type type; }; 54 template<typename T> struct remove_all<T*> { typedef typename remove_all<T>::type type; }; 55 56 template<typename T> struct is_arithmetic { enum { value = false }; }; 57 template<> struct is_arithmetic<float> { enum { value = true }; }; 58 template<> struct is_arithmetic<double> { enum { value = true }; }; 59 template<> struct is_arithmetic<long double> { enum { value = true }; }; 60 template<> struct is_arithmetic<bool> { enum { value = true }; }; 61 template<> struct is_arithmetic<char> { enum { value = true }; }; 62 template<> struct is_arithmetic<signed char> { enum { value = true }; }; 63 template<> struct is_arithmetic<unsigned char> { enum { value = true }; }; 64 template<> struct is_arithmetic<signed short> { enum { value = true }; }; 65 template<> struct is_arithmetic<unsigned short>{ enum { value = true }; }; 66 template<> struct is_arithmetic<signed int> { enum { value = true }; }; 67 template<> struct is_arithmetic<unsigned int> { enum { value = true }; }; 68 template<> struct is_arithmetic<signed long> { enum { value = true }; }; 69 template<> struct is_arithmetic<unsigned long> { enum { value = true }; }; 70 71 template <typename T> struct add_const { typedef const T type; }; 72 template <typename T> struct add_const<T&> { typedef T& type; }; 73 74 template <typename T> struct is_const { enum { value = 0 }; }; 75 template <typename T> struct is_const<T const> { enum { value = 1 }; }; 76 77 template<typename T> struct add_const_on_value_type { typedef const T type; }; 78 template<typename T> struct add_const_on_value_type<T&> { typedef T const& type; }; 79 template<typename T> struct add_const_on_value_type<T*> { typedef T const* type; }; 80 template<typename T> struct add_const_on_value_type<T* const> { typedef T const* const type; }; 81 template<typename T> struct add_const_on_value_type<T const* const> { typedef T const* const type; }; 82 83 /** \internal Allows to enable/disable an overload 84 * according to a compile time condition. 85 */ 86 template<bool Condition, typename T> struct enable_if; 87 88 template<typename T> struct enable_if<true,T> 89 { typedef T type; }; 90 91 92 93 /** \internal 94 * A base class do disable default copy ctor and copy assignement operator. 95 */ 96 class noncopyable 97 { 98 noncopyable(const noncopyable&); 99 const noncopyable& operator=(const noncopyable&); 100 protected: 101 noncopyable() {} 102 ~noncopyable() {} 103 }; 104 105 106 /** \internal 107 * Convenient struct to get the result type of a unary or binary functor. 108 * 109 * It supports both the current STL mechanism (using the result_type member) as well as 110 * upcoming next STL generation (using a templated result member). 111 * If none of these members is provided, then the type of the first argument is returned. FIXME, that behavior is a pretty bad hack. 112 */ 113 template<typename T> struct result_of {}; 114 115 struct has_none {int a[1];}; 116 struct has_std_result_type {int a[2];}; 117 struct has_tr1_result {int a[3];}; 118 119 template<typename Func, typename ArgType, int SizeOf=sizeof(has_none)> 120 struct unary_result_of_select {typedef ArgType type;}; 121 122 template<typename Func, typename ArgType> 123 struct unary_result_of_select<Func, ArgType, sizeof(has_std_result_type)> {typedef typename Func::result_type type;}; 124 125 template<typename Func, typename ArgType> 126 struct unary_result_of_select<Func, ArgType, sizeof(has_tr1_result)> {typedef typename Func::template result<Func(ArgType)>::type type;}; 127 128 template<typename Func, typename ArgType> 129 struct result_of<Func(ArgType)> { 130 template<typename T> 131 static has_std_result_type testFunctor(T const *, typename T::result_type const * = 0); 132 template<typename T> 133 static has_tr1_result testFunctor(T const *, typename T::template result<T(ArgType)>::type const * = 0); 134 static has_none testFunctor(...); 135 136 // note that the following indirection is needed for gcc-3.3 137 enum {FunctorType = sizeof(testFunctor(static_cast<Func*>(0)))}; 138 typedef typename unary_result_of_select<Func, ArgType, FunctorType>::type type; 139 }; 140 141 template<typename Func, typename ArgType0, typename ArgType1, int SizeOf=sizeof(has_none)> 142 struct binary_result_of_select {typedef ArgType0 type;}; 143 144 template<typename Func, typename ArgType0, typename ArgType1> 145 struct binary_result_of_select<Func, ArgType0, ArgType1, sizeof(has_std_result_type)> 146 {typedef typename Func::result_type type;}; 147 148 template<typename Func, typename ArgType0, typename ArgType1> 149 struct binary_result_of_select<Func, ArgType0, ArgType1, sizeof(has_tr1_result)> 150 {typedef typename Func::template result<Func(ArgType0,ArgType1)>::type type;}; 151 152 template<typename Func, typename ArgType0, typename ArgType1> 153 struct result_of<Func(ArgType0,ArgType1)> { 154 template<typename T> 155 static has_std_result_type testFunctor(T const *, typename T::result_type const * = 0); 156 template<typename T> 157 static has_tr1_result testFunctor(T const *, typename T::template result<T(ArgType0,ArgType1)>::type const * = 0); 158 static has_none testFunctor(...); 159 160 // note that the following indirection is needed for gcc-3.3 161 enum {FunctorType = sizeof(testFunctor(static_cast<Func*>(0)))}; 162 typedef typename binary_result_of_select<Func, ArgType0, ArgType1, FunctorType>::type type; 163 }; 164 165 /** \internal In short, it computes int(sqrt(\a Y)) with \a Y an integer. 166 * Usage example: \code meta_sqrt<1023>::ret \endcode 167 */ 168 template<int Y, 169 int InfX = 0, 170 int SupX = ((Y==1) ? 1 : Y/2), 171 bool Done = ((SupX-InfX)<=1 ? true : ((SupX*SupX <= Y) && ((SupX+1)*(SupX+1) > Y))) > 172 // use ?: instead of || just to shut up a stupid gcc 4.3 warning 173 class meta_sqrt 174 { 175 enum { 176 MidX = (InfX+SupX)/2, 177 TakeInf = MidX*MidX > Y ? 1 : 0, 178 NewInf = int(TakeInf) ? InfX : int(MidX), 179 NewSup = int(TakeInf) ? int(MidX) : SupX 180 }; 181 public: 182 enum { ret = meta_sqrt<Y,NewInf,NewSup>::ret }; 183 }; 184 185 template<int Y, int InfX, int SupX> 186 class meta_sqrt<Y, InfX, SupX, true> { public: enum { ret = (SupX*SupX <= Y) ? SupX : InfX }; }; 187 188 /** \internal determines whether the product of two numeric types is allowed and what the return type is */ 189 template<typename T, typename U> struct scalar_product_traits; 190 191 template<typename T> struct scalar_product_traits<T,T> 192 { 193 //enum { Cost = NumTraits<T>::MulCost }; 194 typedef T ReturnType; 195 }; 196 197 template<typename T> struct scalar_product_traits<T,std::complex<T> > 198 { 199 //enum { Cost = 2*NumTraits<T>::MulCost }; 200 typedef std::complex<T> ReturnType; 201 }; 202 203 template<typename T> struct scalar_product_traits<std::complex<T>, T> 204 { 205 //enum { Cost = 2*NumTraits<T>::MulCost }; 206 typedef std::complex<T> ReturnType; 207 }; 208 209 // FIXME quick workaround around current limitation of result_of 210 // template<typename Scalar, typename ArgType0, typename ArgType1> 211 // struct result_of<scalar_product_op<Scalar>(ArgType0,ArgType1)> { 212 // typedef typename scalar_product_traits<typename remove_all<ArgType0>::type, typename remove_all<ArgType1>::type>::ReturnType type; 213 // }; 214 215 template<typename T> struct is_diagonal 216 { enum { ret = false }; }; 217 218 template<typename T> struct is_diagonal<DiagonalBase<T> > 219 { enum { ret = true }; }; 220 221 template<typename T> struct is_diagonal<DiagonalWrapper<T> > 222 { enum { ret = true }; }; 223 224 template<typename T, int S> struct is_diagonal<DiagonalMatrix<T,S> > 225 { enum { ret = true }; }; 226 227 } // end namespace internal 228 229 } // end namespace Eigen 230 231 #endif // EIGEN_META_H 232
