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functortraits.hxx |

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2 /* */
3 /* Copyright 1998-2005 by Ullrich Koethe */
4 /* */
5 /* This file is part of the VIGRA computer vision library. */
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34 /************************************************************************/
35
36
37 #ifndef VIGRA_FUNCTORTRAITS_HXX
38 #define VIGRA_FUNCTORTRAITS_HXX
39
40 #include <functional>
41 #include "metaprogramming.hxx"
42
43 namespace vigra {
44
45 struct InitializerTag {};
46 struct UnaryFunctorTag {};
47 struct BinaryFunctorTag {};
48 struct TernaryFunctorTag {};
49 struct UnaryAnalyserTag {};
50 struct BinaryAnalyserTag {};
51 struct TernaryAnalyserTag {};
52
53 struct UnaryReduceFunctorTag
54 : public InitializerTag, public UnaryAnalyserTag
55 {};
56
57 struct BinaryReduceFunctorTag
58 : public InitializerTag, public BinaryAnalyserTag
59 {};
60
61 typedef UnaryFunctorTag UnaryExpandFunctorTag;
62 typedef BinaryFunctorTag BinaryExpandFunctorTag;
63
64 template <class T>
65 class FunctorTraitsBase
66 {
67 public:
68 typedef T type;
69
70 typedef typename IsDerivedFrom<T, InitializerTag>::result isInitializer;
71
72 typedef typename IsDerivedFrom<T, UnaryFunctorTag>::result isUnaryFunctor;
73 typedef typename IsDerivedFrom<T, BinaryFunctorTag>::result isBinaryFunctor;
74 typedef typename IsDerivedFrom<T, TernaryFunctorTag>::result isTernaryFunctor;
75
76 typedef typename IsDerivedFrom<T, UnaryAnalyserTag>::result isUnaryAnalyser;
77 typedef typename IsDerivedFrom<T, BinaryAnalyserTag>::result isBinaryAnalyser;
78 typedef typename IsDerivedFrom<T, TernaryAnalyserTag>::result isTernaryAnalyser;
79 };
80
81
82
83 /** \addtogroup Functors
84 */
85 //@{
86 /** \brief Export associated information for a functor.
87
88 The FunctorTraits class contains the following fields:
89
90 \code
91 template <class T>
92 struct FunctorTraits
93 {
94 typedef T type;
95
96 typedef ... isInitializer;
97
98 typedef ... isUnaryFunctor;
99 typedef ... isBinaryFunctor;
100 typedef ... isTernaryFunctor;
101
102 typedef ... isUnaryAnalyser;
103 typedef ... isBinaryAnalyser;
104 typedef ... isTernaryAnalyser;
105 };
106 \endcode
107
108 where the dots are either <tt>VigraTrueType</tt> or <tt>VigraFalseType</tt>
109 depending on whether the functor supports the respective functionality or not.
110 Note that these traits are automatically defined correctly when your functor is derived
111 from the appropriate functor tag classes:
112
113 \code
114 struct InitializerTag {};
115 struct UnaryFunctorTag {};
116 struct BinaryFunctorTag {};
117 struct TernaryFunctorTag {};
118 struct UnaryAnalyserTag {};
119 struct BinaryAnalyserTag {};
120 struct TernaryAnalyserTag {};
121 struct UnaryReduceFunctorTag : public InitializerTag, public UnaryAnalyserTag {};
122 struct BinaryReduceFunctorTag : public InitializerTag, public BinaryAnalyserTag {};
123 \endcode
124
125 If a functor <tt>f</tt> is a model of these categories, it supports the following
126 calls (<tt>v</tt> is a variable such that the result type of the functor
127 calls can be converted into <tt>v</tt>'s type, and <tt>a1, a2, a3</tt> are
128 variables convertible into the functor's argument types):
129
130 <DL>
131 <DT><b>Initializer</b>
132 <DD> <tt>v = f()</tt> (used with initImageWithFunctor())
133 <DT><b>UnaryFunctor</b>
134 <DD> <tt>v = f(a1)</tt> (used with transformImage())
135 <DT><b>BinaryFunctor</b>
136 <DD> <tt>v = f(a1, a2)</tt> (used with combineTwoImages())
137 <DT><b>TernaryFunctor</b>
138 <DD> <tt>v = f(a1, a2, a3)</tt> (used with combineThreeImages())
139 <DT><b>UnaryAnalyser</b>
140 <DD> <tt>f(a1)</tt> (return type <tt>void</tt>, used with inspectImage())
141 <DT><b>BinaryAnalyser</b>
142 <DD> <tt>f(a1, a2)</tt> (return type <tt>void</tt>, used with inspectTwoImages())
143 <DT><b>TernaryAnalyser</b>
144 <DD> <tt>f(a1, a2, a3)</tt> (return type <tt>void</tt>)
145 </DL>
146
147 It should be noted that the functor's argument and result types are not contained
148 in the traits class: Since the function calls are often member template functions in
149 VIGRA, many functors do not have fixed argument types. Neither are the result
150 types fixed in this case because they are computed (via a template meta-program)
151 from the argument types.
152
153 <b>\#include</b> <vigra/functortraits.hxx> <br/>
154 Namespace: vigra
155 */
156 template <class T>
157 class FunctorTraits
158 : public FunctorTraitsBase<T>
159 {};
160
161 #define VIGRA_DEFINE_STL_FUNCTOR(name, unary, binary) \
162 template <class T> \
163 class FunctorTraits<name<T> > \
164 { \
165 public: \
166 typedef T type; \
167 \
168 typedef VigraFalseType isInitializer; \
169 \
170 typedef unary isUnaryFunctor; \
171 typedef binary isBinaryFunctor; \
172 typedef VigraFalseType isTernaryFunctor; \
173 \
174 typedef VigraFalseType isUnaryAnalyser; \
175 typedef VigraFalseType isBinaryAnalyser; \
176 typedef VigraFalseType isTernaryAnalyser; \
177 };
178
179 // ???TODO: these should also be specialized for the ptr_fun and mem_fun_ptr wrappers
180 VIGRA_DEFINE_STL_FUNCTOR(std::plus, VigraFalseType, VigraTrueType)
181 VIGRA_DEFINE_STL_FUNCTOR(std::minus, VigraFalseType, VigraTrueType)
182 VIGRA_DEFINE_STL_FUNCTOR(std::multiplies, VigraFalseType, VigraTrueType)
183 VIGRA_DEFINE_STL_FUNCTOR(std::divides, VigraFalseType, VigraTrueType)
184 VIGRA_DEFINE_STL_FUNCTOR(std::modulus, VigraFalseType, VigraTrueType)
185 VIGRA_DEFINE_STL_FUNCTOR(std::equal_to, VigraFalseType, VigraTrueType)
186 VIGRA_DEFINE_STL_FUNCTOR(std::not_equal_to, VigraFalseType, VigraTrueType)
187 VIGRA_DEFINE_STL_FUNCTOR(std::greater, VigraFalseType, VigraTrueType)
188 VIGRA_DEFINE_STL_FUNCTOR(std::less, VigraFalseType, VigraTrueType)
189 VIGRA_DEFINE_STL_FUNCTOR(std::greater_equal, VigraFalseType, VigraTrueType)
190 VIGRA_DEFINE_STL_FUNCTOR(std::less_equal, VigraFalseType, VigraTrueType)
191 VIGRA_DEFINE_STL_FUNCTOR(std::logical_and, VigraFalseType, VigraTrueType)
192 VIGRA_DEFINE_STL_FUNCTOR(std::logical_or, VigraFalseType, VigraTrueType)
193 VIGRA_DEFINE_STL_FUNCTOR(std::binary_negate, VigraFalseType, VigraTrueType)
194
195 VIGRA_DEFINE_STL_FUNCTOR(std::negate, VigraTrueType, VigraFalseType)
196 VIGRA_DEFINE_STL_FUNCTOR(std::logical_not, VigraTrueType, VigraFalseType)
197 VIGRA_DEFINE_STL_FUNCTOR(std::unary_negate, VigraTrueType, VigraFalseType)
198 VIGRA_DEFINE_STL_FUNCTOR(std::binder1st, VigraTrueType, VigraFalseType)
199 VIGRA_DEFINE_STL_FUNCTOR(std::binder2nd, VigraTrueType, VigraFalseType)
200 #undef VIGRA_DEFINE_STL_FUNCTOR
201
202 template <class R>
203 class FunctorTraits<R (*)()>
204 {
205 public:
206 typedef R (*type)();
207
208 typedef VigraTrueType isInitializer;
209 typedef VigraFalseType isUnaryFunctor;
210 typedef VigraFalseType isBinaryFunctor;
211 typedef VigraFalseType isTernaryFunctor;
212 typedef VigraFalseType isUnaryAnalyser;
213 typedef VigraFalseType isBinaryAnalyser;
214 typedef VigraFalseType isTernaryAnalyser;
215 };
216
217 template <class R, class T>
218 class FunctorTraits<R (*)(T)>
219 {
220 public:
221 typedef R (*type)(T);
222
223 typedef VigraFalseType isInitializer;
224 typedef VigraTrueType isUnaryFunctor;
225 typedef VigraFalseType isBinaryFunctor;
226 typedef VigraFalseType isTernaryFunctor;
227 typedef VigraFalseType isUnaryAnalyser;
228 typedef VigraFalseType isBinaryAnalyser;
229 typedef VigraFalseType isTernaryAnalyser;
230 };
231
232 template <class R, class T1, class T2>
233 class FunctorTraits<R (*)(T1, T2)>
234 {
235 public:
236 typedef R (*type)(T1, T2);
237
238 typedef VigraFalseType isInitializer;
239 typedef VigraFalseType isUnaryFunctor;
240 typedef VigraTrueType isBinaryFunctor;
241 typedef VigraFalseType isTernaryFunctor;
242 typedef VigraFalseType isUnaryAnalyser;
243 typedef VigraFalseType isBinaryAnalyser;
244 typedef VigraFalseType isTernaryAnalyser;
245 };
246
247 template <class R, class T1, class T2, class T3>
248 class FunctorTraits<R (*)(T1, T2, T3)>
249 {
250 public:
251 typedef R (*type)(T1, T2, T3);
252
253 typedef VigraFalseType isInitializer;
254 typedef VigraFalseType isUnaryFunctor;
255 typedef VigraFalseType isBinaryFunctor;
256 typedef VigraTrueType isTernaryFunctor;
257 typedef VigraFalseType isUnaryAnalyser;
258 typedef VigraFalseType isBinaryAnalyser;
259 typedef VigraFalseType isTernaryAnalyser;
260 };
261
262 //@}
263
264 } // namespace vigra
265
266 #endif // VIGRA_FUNCTORTRAITS_HXX
vigra::FunctorTraits
Export associated information for a functor.
Definition: functortraits.hxx:157

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de) Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany | html generated using doxygen and Python vigra 1.11.0 (Thu Mar 17 2016)