Milena (Olena)
User documentation 2.0a Id
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00001 // Copyright (C) 2008, 2009, 2010 EPITA Research and Development 00002 // Laboratory (LRDE) 00003 // 00004 // This file is part of Olena. 00005 // 00006 // Olena is free software: you can redistribute it and/or modify it under 00007 // the terms of the GNU General Public License as published by the Free 00008 // Software Foundation, version 2 of the License. 00009 // 00010 // Olena is distributed in the hope that it will be useful, 00011 // but WITHOUT ANY WARRANTY; without even the implied warranty of 00012 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 00013 // General Public License for more details. 00014 // 00015 // You should have received a copy of the GNU General Public License 00016 // along with Olena. If not, see <http://www.gnu.org/licenses/>. 00017 // 00018 // As a special exception, you may use this file as part of a free 00019 // software project without restriction. Specifically, if other files 00020 // instantiate templates or use macros or inline functions from this 00021 // file, or you compile this file and link it with other files to produce 00022 // an executable, this file does not by itself cause the resulting 00023 // executable to be covered by the GNU General Public License. This 00024 // exception does not however invalidate any other reasons why the 00025 // executable file might be covered by the GNU General Public License. 00026 00027 #ifndef MLN_CONVERT_FROM_TO_HH 00028 # define MLN_CONVERT_FROM_TO_HH 00029 00039 00040 # include <mln/convert/impl/all.hh> 00041 # include <mln/convert/from_to.hxx> 00042 00043 # include <mln/metal/abort.hh> 00044 # include <mln/metal/converts_to.hh> 00045 # include <mln/metal/is.hh> 00046 # include <mln/metal/is_a.hh> 00047 00048 # include <mln/value/cast.hh> 00049 00050 namespace mln 00051 { 00052 00053 // Forward declarations. 00054 template <typename E> struct Object; 00055 template <typename E> struct Value; 00056 template <typename E> struct Site_Set; 00057 template <typename E> struct Image; 00058 00059 namespace convert 00060 { 00061 00062 template <typename F, typename T> 00063 void 00064 from_to(const F& from, T& to); 00065 00066 00067 # ifndef MLN_INCLUDE_ONLY 00068 00069 namespace internal 00070 { 00071 00072 // Dispatch to specific implementation. 00073 00074 // Image -> Site_Set. 00075 template <typename I, typename S> 00076 inline 00077 void 00078 from_to_dispatch(const Image<I>& from, Site_Set<S>& to) 00079 { 00080 mlc_is(mln_trait_site_set_contents(S), 00081 mln::trait::site_set::contents::dynamic)::check(); 00082 mln_precondition(exact(from).is_valid()); 00083 mln::convert::impl::from_image_to_site_set(from, to); 00084 } 00085 00086 00087 // Site_Set -> Image. 00088 template <typename S, typename I> 00089 inline 00090 void 00091 from_to_dispatch(const Site_Set<S>& from, Image<I>& to) 00092 { 00093 mlc_converts_to(mln_site(S), mln_site(I))::check(); // FIXME: Is it too restrictive? 00094 mln_precondition(exact(from).is_valid()); 00095 mln::convert::impl::from_site_set_to_image(from, to); 00096 } 00097 00098 00099 // Value -> Value 00100 template <typename F, typename T> 00101 inline 00102 void 00103 from_to_dispatch(const Value<F>& from, Value<T>& to) 00104 { 00105 mln::convert::impl::from_value_to_value(from, to); 00106 } 00107 00108 00109 00110 // Dispatch related to convertible objects. 00111 00112 // F -> T 00113 // if F convertible to T. 00114 template <typename F, typename T> 00115 inline 00116 void 00117 from_to_dispatch(metal::true_, 00118 const Object<F>& from, Object<T>& to) 00119 { 00120 exact(to) = exact(from); 00121 } 00122 00123 00124 // F is NOT convertible to T. 00125 template <typename F, typename T> 00126 inline 00127 void 00128 from_to_dispatch(metal::false_, 00129 const Object<F>& from, Object<T>& to) 00130 { 00131 over_load::from_to_(exact(from), exact(to)); 00132 } 00133 00134 00135 00136 // Default dispatch if the two arguments are objects. 00137 00138 // Object -> Object 00139 template <typename F, typename T> 00140 inline 00141 void 00142 from_to_dispatch(const Object<F>& from, Object<T>& to) 00143 { 00144 typedef mlc_converts_to(F, T) F_converts_to_T; // FIXME: HERE we've got a problem with g++-2.95. 00145 internal::from_to_dispatch(F_converts_to_T(), 00146 exact(from), exact(to)); 00147 } 00148 00149 00150 00151 // Dispatch entry points. 00152 // Check whether arguments are an object or not. 00153 00154 // Builtin -> Builtin 00155 template <typename F, typename T> 00156 inline 00157 void 00158 from_to_dispatch(metal::false_, const F& from, 00159 metal::false_, T& to) 00160 { 00161 over_load::from_to_(from, to); 00162 } 00163 00164 00165 // Object -> Builtin 00166 template <typename F, typename T> 00167 inline 00168 void 00169 from_to_dispatch(metal::true_, const F& from, 00170 metal::false_, T& to) 00171 { 00172 over_load::from_to_(exact(from), to); 00173 } 00174 00175 00176 // Builtin -> Object 00177 template <typename F, typename T> 00178 inline 00179 void 00180 from_to_dispatch(metal::false_, const F& from, 00181 metal::true_, T& to) 00182 { 00183 over_load::from_to_(from, exact(to)); 00184 } 00185 00186 // Object -> Object 00187 template <typename F, typename T> 00188 inline 00189 void 00190 from_to_dispatch(metal::true_, const F& from, 00191 metal::true_, T& to) 00192 { 00193 internal::from_to_dispatch(exact(from), exact(to)); 00194 } 00195 00196 00197 } // end of namespace mln::convert::internal 00198 00199 00200 namespace over_load 00201 { 00202 00203 00204 // Object -> Object (F not convertible towards T) 00205 // No conversion exists! 00206 template <typename F, typename T> 00207 void 00208 from_to_(const Object<F>&, Object<T>&) 00209 { 00210 // This particular from-to is not defined! 00211 // 00212 // Either this conversion is meaningless or an overload is 00213 // missing. 00214 mlc_abort(F)::check(); 00215 } 00216 00217 00218 // Object -> Object 00219 template <typename T> 00220 inline 00221 void 00222 from_to_(const Object<T>& from, Object<T>& to) 00223 { 00224 exact(to) = exact(from); 00225 } 00226 00227 00228 // Exact same type. 00229 template <typename T> 00230 inline 00231 void 00232 from_to_(const T& from, T& to) 00233 { 00234 to = from; 00235 } 00236 00237 00238 // Default conversion. 00239 template <typename F, typename T> 00240 inline 00241 void 00242 from_to_(const F& from, T& to) 00243 { 00244 to = mln::value::cast<T>(from); 00245 } 00246 00247 00248 } // end of namespace mln::convert::over_load 00249 00250 00251 00252 // Facade 00253 00254 template <typename F, typename T> 00255 inline 00256 void 00257 from_to(const F& from, T& to) 00258 { 00259 typedef mlc_is_a(F, Object) F_is_object; 00260 typedef mlc_is_a(T, Object) T_is_object; 00261 internal::from_to_dispatch(F_is_object(), from, 00262 T_is_object(), to); 00263 } 00264 00265 00266 # endif // ! MLN_INCLUDE_ONLY 00267 00268 } // end of namespace mln::convert 00269 00270 } // end of namespace mln 00271 00272 00273 #endif // ! MLN_CONVERT_FROM_TO_HH