aboutsummaryrefslogtreecommitdiffhomepage
path: root/Eigen/src/Core/util/Meta.h
blob: 3d28680b67a23acd25a1a1b351f1ee9131a9dd71 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
// This file is part of Eigen, a lightweight C++ template library
// for linear algebra.
//
// Copyright (C) 2008-2009 Gael Guennebaud <gael.guennebaud@inria.fr>
// Copyright (C) 2006-2008 Benoit Jacob <jacob.benoit.1@gmail.com>
//
// Eigen is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 3 of the License, or (at your option) any later version.
//
// Alternatively, you can redistribute it and/or
// modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation; either version 2 of
// the License, or (at your option) any later version.
//
// Eigen is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
// FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License or the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public
// License and a copy of the GNU General Public License along with
// Eigen. If not, see <http://www.gnu.org/licenses/>.

#ifndef EIGEN_META_H
#define EIGEN_META_H

/** \internal
  * \file Meta.h
  * This file contains generic metaprogramming classes which are not specifically related to Eigen.
  * \note In case you wonder, yes we're aware that Boost already provides all these features,
  * we however don't want to add a dependency to Boost.
  */

struct ei_meta_true {  enum { ret = 1 }; };
struct ei_meta_false { enum { ret = 0 }; };

template<bool Condition, typename Then, typename Else>
struct ei_meta_if { typedef Then ret; };

template<typename Then, typename Else>
struct ei_meta_if <false, Then, Else> { typedef Else ret; };

template<typename T, typename U> struct ei_is_same_type { enum { ret = 0 }; };
template<typename T> struct ei_is_same_type<T,T> { enum { ret = 1 }; };

template<typename T> struct ei_unref { typedef T type; };
template<typename T> struct ei_unref<T&> { typedef T type; };

template<typename T> struct ei_unpointer { typedef T type; };
template<typename T> struct ei_unpointer<T*> { typedef T type; };
template<typename T> struct ei_unpointer<T*const> { typedef T type; };

template<typename T> struct ei_unconst { typedef T type; };
template<typename T> struct ei_unconst<const T> { typedef T type; };
template<typename T> struct ei_unconst<T const &> { typedef T & type; };
template<typename T> struct ei_unconst<T const *> { typedef T * type; };

template<typename T> struct ei_cleantype { typedef T type; };
template<typename T> struct ei_cleantype<const T>   { typedef typename ei_cleantype<T>::type type; };
template<typename T> struct ei_cleantype<const T&>  { typedef typename ei_cleantype<T>::type type; };
template<typename T> struct ei_cleantype<T&>        { typedef typename ei_cleantype<T>::type type; };
template<typename T> struct ei_cleantype<const T*>  { typedef typename ei_cleantype<T>::type type; };
template<typename T> struct ei_cleantype<T*>        { typedef typename ei_cleantype<T>::type type; };

template<typename T> struct ei_is_arithmetic      { enum { ret = false }; };
template<> struct ei_is_arithmetic<float>         { enum { ret = true }; };
template<> struct ei_is_arithmetic<double>        { enum { ret = true }; };
template<> struct ei_is_arithmetic<long double>   { enum { ret = true }; };
template<> struct ei_is_arithmetic<bool>          { enum { ret = true }; };
template<> struct ei_is_arithmetic<char>          { enum { ret = true }; };
template<> struct ei_is_arithmetic<signed char>   { enum { ret = true }; };
template<> struct ei_is_arithmetic<unsigned char> { enum { ret = true }; };
template<> struct ei_is_arithmetic<signed short>  { enum { ret = true }; };
template<> struct ei_is_arithmetic<unsigned short>{ enum { ret = true }; };
template<> struct ei_is_arithmetic<signed int>    { enum { ret = true }; };
template<> struct ei_is_arithmetic<unsigned int>  { enum { ret = true }; };
template<> struct ei_is_arithmetic<signed long>   { enum { ret = true }; };
template<> struct ei_is_arithmetic<unsigned long> { enum { ret = true }; };
template<> struct ei_is_arithmetic<signed long long>   { enum { ret = true }; };
template<> struct ei_is_arithmetic<unsigned long long> { enum { ret = true }; };

template<typename T> struct ei_makeconst            { typedef const T type;  };
template<typename T> struct ei_makeconst<const T>   { typedef const T type;  };
template<typename T> struct ei_makeconst<T&>        { typedef const T& type; };
template<typename T> struct ei_makeconst<const T&>  { typedef const T& type; };
template<typename T> struct ei_makeconst<T*>        { typedef const T* type; };
template<typename T> struct ei_makeconst<const T*>  { typedef const T* type; };

template<typename T> struct ei_makeconst_return_type
{
  typedef typename ei_meta_if<ei_is_arithmetic<T>::ret, T, typename ei_makeconst<T>::type>::ret type;
};

/** \internal Allows to enable/disable an overload
  * according to a compile time condition.
  */
template<bool Condition, typename T> struct ei_enable_if;

template<typename T> struct ei_enable_if<true,T>
{ typedef T type; };

/** \internal
  * Convenient struct to get the result type of a unary or binary functor.
  *
  * It supports both the current STL mechanism (using the result_type member) as well as
  * upcoming next STL generation (using a templated result member).
  * If none of these members is provided, then the type of the first argument is returned. FIXME, that behavior is a pretty bad hack.
  */
template<typename T> struct ei_result_of {};

struct ei_has_none {int a[1];};
struct ei_has_std_result_type {int a[2];};
struct ei_has_tr1_result {int a[3];};

template<typename Func, typename ArgType, int SizeOf=sizeof(ei_has_none)>
struct ei_unary_result_of_select {typedef ArgType type;};

template<typename Func, typename ArgType>
struct ei_unary_result_of_select<Func, ArgType, sizeof(ei_has_std_result_type)> {typedef typename Func::result_type type;};

template<typename Func, typename ArgType>
struct ei_unary_result_of_select<Func, ArgType, sizeof(ei_has_tr1_result)> {typedef typename Func::template result<Func(ArgType)>::type type;};

template<typename Func, typename ArgType>
struct ei_result_of<Func(ArgType)> {
    template<typename T>
    static ei_has_std_result_type testFunctor(T const *, typename T::result_type const * = 0);
    template<typename T>
    static ei_has_tr1_result      testFunctor(T const *, typename T::template result<T(ArgType)>::type const * = 0);
    static ei_has_none            testFunctor(...);

    // note that the following indirection is needed for gcc-3.3
    enum {FunctorType = sizeof(testFunctor(static_cast<Func*>(0)))};
    typedef typename ei_unary_result_of_select<Func, ArgType, FunctorType>::type type;
};

template<typename Func, typename ArgType0, typename ArgType1, int SizeOf=sizeof(ei_has_none)>
struct ei_binary_result_of_select {typedef ArgType0 type;};

template<typename Func, typename ArgType0, typename ArgType1>
struct ei_binary_result_of_select<Func, ArgType0, ArgType1, sizeof(ei_has_std_result_type)>
{typedef typename Func::result_type type;};

template<typename Func, typename ArgType0, typename ArgType1>
struct ei_binary_result_of_select<Func, ArgType0, ArgType1, sizeof(ei_has_tr1_result)>
{typedef typename Func::template result<Func(ArgType0,ArgType1)>::type type;};

template<typename Func, typename ArgType0, typename ArgType1>
struct ei_result_of<Func(ArgType0,ArgType1)> {
    template<typename T>
    static ei_has_std_result_type testFunctor(T const *, typename T::result_type const * = 0);
    template<typename T>
    static ei_has_tr1_result      testFunctor(T const *, typename T::template result<T(ArgType0,ArgType1)>::type const * = 0);
    static ei_has_none            testFunctor(...);

    // note that the following indirection is needed for gcc-3.3
    enum {FunctorType = sizeof(testFunctor(static_cast<Func*>(0)))};
    typedef typename ei_binary_result_of_select<Func, ArgType0, ArgType1, FunctorType>::type type;
};

/** \internal In short, it computes int(sqrt(\a Y)) with \a Y an integer.
  * Usage example: \code ei_meta_sqrt<1023>::ret \endcode
  */
template<int Y,
         int InfX = 0,
         int SupX = ((Y==1) ? 1 : Y/2),
         bool Done = ((SupX-InfX)<=1 ? true : ((SupX*SupX <= Y) && ((SupX+1)*(SupX+1) > Y))) >
                                // use ?: instead of || just to shut up a stupid gcc 4.3 warning
class ei_meta_sqrt
{
    enum {
      MidX = (InfX+SupX)/2,
      TakeInf = MidX*MidX > Y ? 1 : 0,
      NewInf = int(TakeInf) ? InfX : int(MidX),
      NewSup = int(TakeInf) ? int(MidX) : SupX
    };
  public:
    enum { ret = ei_meta_sqrt<Y,NewInf,NewSup>::ret };
};

template<int Y, int InfX, int SupX>
class ei_meta_sqrt<Y, InfX, SupX, true> { public:  enum { ret = (SupX*SupX <= Y) ? SupX : InfX }; };

/** \internal determines whether the product of two numeric types is allowed and what the return type is */
template<typename T, typename U> struct ei_scalar_product_traits;

template<typename T> struct ei_scalar_product_traits<T,T>
{
  //enum { Cost = NumTraits<T>::MulCost };
  typedef T ReturnType;
};

template<typename T> struct ei_scalar_product_traits<T,std::complex<T> >
{
  //enum { Cost = 2*NumTraits<T>::MulCost };
  typedef std::complex<T> ReturnType;
};

template<typename T> struct ei_scalar_product_traits<std::complex<T>, T>
{
  //enum { Cost = 2*NumTraits<T>::MulCost  };
  typedef std::complex<T> ReturnType;
};

// FIXME quick workaround around current limitation of ei_result_of
// template<typename Scalar, typename ArgType0, typename ArgType1>
// struct ei_result_of<ei_scalar_product_op<Scalar>(ArgType0,ArgType1)> {
// typedef typename ei_scalar_product_traits<typename ei_cleantype<ArgType0>::type, typename ei_cleantype<ArgType1>::type>::ReturnType type;
// };

template<typename T> struct ei_is_diagonal
{ enum { ret = false }; };

template<typename T> struct ei_is_diagonal<DiagonalBase<T> >
{ enum { ret = true }; };

template<typename T> struct ei_is_diagonal<DiagonalWrapper<T> >
{ enum { ret = true }; };

template<typename T, int S> struct ei_is_diagonal<DiagonalMatrix<T,S> >
{ enum { ret = true }; };

#endif // EIGEN_META_H