1 // This file is part of Eigen, a lightweight C++ template library 2 // for linear algebra. 3 // 4 // Copyright (C) 2011 Benoit Jacob <jacob.benoit.1 (at) gmail.com> 5 // 6 // This Source Code Form is subject to the terms of the Mozilla 7 // Public License v. 2.0. If a copy of the MPL was not distributed 8 // with this file, You can obtain one at http://mozilla.org/MPL/2.0/. 9 10 #ifndef EIGEN2_META_H 11 #define EIGEN2_META_H 12 13 namespace Eigen { 14 15 template<typename T> 16 struct ei_traits : internal::traits<T> 17 {}; 18 19 struct ei_meta_true { enum { ret = 1 }; }; 20 struct ei_meta_false { enum { ret = 0 }; }; 21 22 template<bool Condition, typename Then, typename Else> 23 struct ei_meta_if { typedef Then ret; }; 24 25 template<typename Then, typename Else> 26 struct ei_meta_if <false, Then, Else> { typedef Else ret; }; 27 28 template<typename T, typename U> struct ei_is_same_type { enum { ret = 0 }; }; 29 template<typename T> struct ei_is_same_type<T,T> { enum { ret = 1 }; }; 30 31 template<typename T> struct ei_unref { typedef T type; }; 32 template<typename T> struct ei_unref<T&> { typedef T type; }; 33 34 template<typename T> struct ei_unpointer { typedef T type; }; 35 template<typename T> struct ei_unpointer<T*> { typedef T type; }; 36 template<typename T> struct ei_unpointer<T*const> { typedef T type; }; 37 38 template<typename T> struct ei_unconst { typedef T type; }; 39 template<typename T> struct ei_unconst<const T> { typedef T type; }; 40 template<typename T> struct ei_unconst<T const &> { typedef T & type; }; 41 template<typename T> struct ei_unconst<T const *> { typedef T * type; }; 42 43 template<typename T> struct ei_cleantype { typedef T type; }; 44 template<typename T> struct ei_cleantype<const T> { typedef typename ei_cleantype<T>::type type; }; 45 template<typename T> struct ei_cleantype<const T&> { typedef typename ei_cleantype<T>::type type; }; 46 template<typename T> struct ei_cleantype<T&> { typedef typename ei_cleantype<T>::type type; }; 47 template<typename T> struct ei_cleantype<const T*> { typedef typename ei_cleantype<T>::type type; }; 48 template<typename T> struct ei_cleantype<T*> { typedef typename ei_cleantype<T>::type type; }; 49 50 /** \internal In short, it computes int(sqrt(\a Y)) with \a Y an integer. 51 * Usage example: \code ei_meta_sqrt<1023>::ret \endcode 52 */ 53 template<int Y, 54 int InfX = 0, 55 int SupX = ((Y==1) ? 1 : Y/2), 56 bool Done = ((SupX-InfX)<=1 ? true : ((SupX*SupX <= Y) && ((SupX+1)*(SupX+1) > Y))) > 57 // use ?: instead of || just to shut up a stupid gcc 4.3 warning 58 class ei_meta_sqrt 59 { 60 enum { 61 MidX = (InfX+SupX)/2, 62 TakeInf = MidX*MidX > Y ? 1 : 0, 63 NewInf = int(TakeInf) ? InfX : int(MidX), 64 NewSup = int(TakeInf) ? int(MidX) : SupX 65 }; 66 public: 67 enum { ret = ei_meta_sqrt<Y,NewInf,NewSup>::ret }; 68 }; 69 70 template<int Y, int InfX, int SupX> 71 class ei_meta_sqrt<Y, InfX, SupX, true> { public: enum { ret = (SupX*SupX <= Y) ? SupX : InfX }; }; 72 73 } // end namespace Eigen 74 75 #endif // EIGEN2_META_H 76
