Milena (Olena)
User documentation 2.0a Id
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00001 // Copyright (C) 2007, 2008, 2009 EPITA Research and Development Laboratory (LRDE) 00002 // 00003 // This file is part of Olena. 00004 // 00005 // Olena is free software: you can redistribute it and/or modify it under 00006 // the terms of the GNU General Public License as published by the Free 00007 // Software Foundation, version 2 of the License. 00008 // 00009 // Olena is distributed in the hope that it will be useful, 00010 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00011 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00012 // General Public License for more details. 00013 // 00014 // You should have received a copy of the GNU General Public License 00015 // along with Olena. If not, see <http://www.gnu.org/licenses/>. 00016 // 00017 // As a special exception, you may use this file as part of a free 00018 // software project without restriction. Specifically, if other files 00019 // instantiate templates or use macros or inline functions from this 00020 // file, or you compile this file and link it with other files to produce 00021 // an executable, this file does not by itself cause the resulting 00022 // executable to be covered by the GNU General Public License. This 00023 // exception does not however invalidate any other reasons why the 00024 // executable file might be covered by the GNU General Public License. 00025 00026 #ifndef MLN_METAL_CONVERTS_TO_HH 00027 # define MLN_METAL_CONVERTS_TO_HH 00028 00033 00034 # include <mln/metal/is_a.hh> 00035 # include <mln/metal/const.hh> 00036 # include <mln/core/def/coord.hh> 00037 00038 00039 # define mlc_converts_to(T, U) mln::metal::converts_to< T, U > 00040 00041 00042 00043 namespace mln 00044 { 00045 00046 // Forward declarations. 00047 namespace value { 00048 template <unsigned n> struct int_u; 00049 template <unsigned n> struct int_s; 00050 } 00051 00052 00053 namespace metal 00054 { 00055 00056 namespace internal 00057 { 00058 00059 struct eat // Required by g++-2.95 for selector to work. 00060 { 00061 template <typename T> eat(const volatile T&); 00062 template <typename T> eat(T&); 00063 }; 00064 00065 template <typename T, typename U> 00066 struct helper_converts_to_ 00067 { 00068 static yes_ selector(U, int); 00069 static no_ selector(eat, ...); 00070 }; 00071 00072 } // end of namespace mln::metal::internal 00073 00074 00075 00077 template <typename T, typename U> 00078 struct converts_to : bool_<( sizeof(internal::helper_converts_to_<T, U> 00079 ::selector(*internal::make_<mlc_const(T)>::ptr(), 00080 0) ) 00081 == 00082 sizeof(internal::yes_) )> 00083 {}; 00084 00085 00086 template <typename T, typename U> 00087 struct converts_to<T*, U*> : converts_to<T, U> 00088 {}; 00089 00090 template <typename T, typename U> 00091 struct converts_to<T**, U**> : false_ 00092 {}; 00093 00094 00095 00096 // Below, a few hacks to quiet g++-3.4 warnings: 00097 00098 template <> struct converts_to< float, int > : true_ {}; 00099 template <> struct converts_to< float, def::coord > : true_ {}; 00100 template <unsigned n> struct converts_to< float, value::int_u<n> > : true_ {}; 00101 template <unsigned n> struct converts_to< float, value::int_s<n> > : true_ {}; 00102 00103 template <> struct converts_to< double, int > : true_ {}; 00104 template <> struct converts_to< double, def::coord > : true_ {}; 00105 template <unsigned n> struct converts_to< double, value::int_u<n> > : true_ {}; 00106 template <unsigned n> struct converts_to< double, value::int_s<n> > : true_ {}; 00107 00108 // End of hacks. 00109 00110 } // end of namespace mln::metal 00111 00112 00113 00114 } // end of namespace mln 00115 00116 00117 #endif // ! MLN_METAL_CONVERTS_TO_HH