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EmulateArray.h
1// This file is part of Eigen, a lightweight C++ template library
2// for linear algebra.
3//
4// Copyright (C) 2014 Benoit Steiner <benoit.steiner.goog@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 EIGEN_EMULATE_ARRAY_H
11#define EIGEN_EMULATE_ARRAY_H
12
13
14
15// The array class is only available starting with cxx11. Emulate our own here
16// if needed. Beware, msvc still doesn't advertise itself as a c++11 compiler!
17// Moreover, CUDA doesn't support the STL containers, so we use our own instead.
18#if (__cplusplus <= 199711L && EIGEN_COMP_MSVC < 1900) || defined(__CUDACC__) || defined(EIGEN_AVOID_STL_ARRAY)
19
20namespace Eigen {
21template <typename T, size_t n> class array {
22 public:
23 EIGEN_DEVICE_FUNC
24 EIGEN_STRONG_INLINE T& operator[] (size_t index) { return values[index]; }
25 EIGEN_DEVICE_FUNC
26 EIGEN_STRONG_INLINE const T& operator[] (size_t index) const { return values[index]; }
27
28 EIGEN_DEVICE_FUNC
29 EIGEN_STRONG_INLINE T& front() { return values[0]; }
30 EIGEN_DEVICE_FUNC
31 EIGEN_STRONG_INLINE const T& front() const { return values[0]; }
32
33 EIGEN_DEVICE_FUNC
34 EIGEN_STRONG_INLINE T& back() { return values[n-1]; }
35 EIGEN_DEVICE_FUNC
36 EIGEN_STRONG_INLINE const T& back() const { return values[n-1]; }
37
38 EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE
39 static std::size_t size() { return n; }
40
41 T values[n];
42
43 EIGEN_DEVICE_FUNC
44 EIGEN_STRONG_INLINE array() { }
45 EIGEN_DEVICE_FUNC
46 EIGEN_STRONG_INLINE array(const T& v) {
47 EIGEN_STATIC_ASSERT(n==1, YOU_MADE_A_PROGRAMMING_MISTAKE)
48 values[0] = v;
49 }
50 EIGEN_DEVICE_FUNC
51 EIGEN_STRONG_INLINE array(const T& v1, const T& v2) {
52 EIGEN_STATIC_ASSERT(n==2, YOU_MADE_A_PROGRAMMING_MISTAKE)
53 values[0] = v1;
54 values[1] = v2;
55 }
56 EIGEN_DEVICE_FUNC
57 EIGEN_STRONG_INLINE array(const T& v1, const T& v2, const T& v3) {
58 EIGEN_STATIC_ASSERT(n==3, YOU_MADE_A_PROGRAMMING_MISTAKE)
59 values[0] = v1;
60 values[1] = v2;
61 values[2] = v3;
62 }
63 EIGEN_DEVICE_FUNC
64 EIGEN_STRONG_INLINE array(const T& v1, const T& v2, const T& v3,
65 const T& v4) {
66 EIGEN_STATIC_ASSERT(n==4, YOU_MADE_A_PROGRAMMING_MISTAKE)
67 values[0] = v1;
68 values[1] = v2;
69 values[2] = v3;
70 values[3] = v4;
71 }
72 EIGEN_DEVICE_FUNC
73 EIGEN_STRONG_INLINE array(const T& v1, const T& v2, const T& v3, const T& v4,
74 const T& v5) {
75 EIGEN_STATIC_ASSERT(n==5, YOU_MADE_A_PROGRAMMING_MISTAKE)
76 values[0] = v1;
77 values[1] = v2;
78 values[2] = v3;
79 values[3] = v4;
80 values[4] = v5;
81 }
82 EIGEN_DEVICE_FUNC
83 EIGEN_STRONG_INLINE array(const T& v1, const T& v2, const T& v3, const T& v4,
84 const T& v5, const T& v6) {
85 EIGEN_STATIC_ASSERT(n==6, YOU_MADE_A_PROGRAMMING_MISTAKE)
86 values[0] = v1;
87 values[1] = v2;
88 values[2] = v3;
89 values[3] = v4;
90 values[4] = v5;
91 values[5] = v6;
92 }
93 EIGEN_DEVICE_FUNC
94 EIGEN_STRONG_INLINE array(const T& v1, const T& v2, const T& v3, const T& v4,
95 const T& v5, const T& v6, const T& v7) {
96 EIGEN_STATIC_ASSERT(n==7, YOU_MADE_A_PROGRAMMING_MISTAKE)
97 values[0] = v1;
98 values[1] = v2;
99 values[2] = v3;
100 values[3] = v4;
101 values[4] = v5;
102 values[5] = v6;
103 values[6] = v7;
104 }
105 EIGEN_DEVICE_FUNC
106 EIGEN_STRONG_INLINE array(
107 const T& v1, const T& v2, const T& v3, const T& v4,
108 const T& v5, const T& v6, const T& v7, const T& v8) {
109 EIGEN_STATIC_ASSERT(n==8, YOU_MADE_A_PROGRAMMING_MISTAKE)
110 values[0] = v1;
111 values[1] = v2;
112 values[2] = v3;
113 values[3] = v4;
114 values[4] = v5;
115 values[5] = v6;
116 values[6] = v7;
117 values[7] = v8;
118 }
119
120#if EIGEN_HAS_VARIADIC_TEMPLATES
121 EIGEN_DEVICE_FUNC
122 EIGEN_STRONG_INLINE array(std::initializer_list<T> l) {
123 eigen_assert(l.size() == n);
124 internal::smart_copy(l.begin(), l.end(), values);
125 }
126#endif
127};
128
129
130// Specialize array for zero size
131template <typename T> class array<T, 0> {
132 public:
133 EIGEN_DEVICE_FUNC
134 EIGEN_STRONG_INLINE T& operator[] (size_t) {
135 eigen_assert(false && "Can't index a zero size array");
136 return dummy;
137 }
138 EIGEN_DEVICE_FUNC
139 EIGEN_STRONG_INLINE const T& operator[] (size_t) const {
140 eigen_assert(false && "Can't index a zero size array");
141 return dummy;
142 }
143
144 EIGEN_DEVICE_FUNC
145 EIGEN_STRONG_INLINE T& front() {
146 eigen_assert(false && "Can't index a zero size array");
147 return dummy;
148 }
149 EIGEN_DEVICE_FUNC
150 EIGEN_STRONG_INLINE const T& front() const {
151 eigen_assert(false && "Can't index a zero size array");
152 return dummy;
153 }
154 EIGEN_DEVICE_FUNC
155 EIGEN_STRONG_INLINE T& back() {
156 eigen_assert(false && "Can't index a zero size array");
157 return dummy;
158 }
159 EIGEN_DEVICE_FUNC
160 EIGEN_STRONG_INLINE const T& back() const {
161 eigen_assert(false && "Can't index a zero size array");
162 return dummy;
163 }
164
165 static EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE std::size_t size() { return 0; }
166
167 EIGEN_DEVICE_FUNC
168 EIGEN_STRONG_INLINE array() : dummy() { }
169
170#if EIGEN_HAS_VARIADIC_TEMPLATES
171 EIGEN_DEVICE_FUNC array(std::initializer_list<T> l) : dummy() {
172 EIGEN_ONLY_USED_FOR_DEBUG(l);
173 eigen_assert(l.size() == 0);
174 }
175#endif
176
177 private:
178 T dummy;
179};
180
181// Comparison operator
182// Todo: implement !=, <, <=, >, and >=
183template<class T, std::size_t N>
184EIGEN_DEVICE_FUNC bool operator==(const array<T,N>& lhs, const array<T,N>& rhs) {
185 for (std::size_t i = 0; i < N; ++i) {
186 if (lhs[i] != rhs[i]) {
187 return false;
188 }
189 }
190 return true;
191}
192
193
194namespace internal {
195template<std::size_t I, class T, std::size_t N>
196EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE T& array_get(array<T,N>& a) {
197 return a[I];
198}
199template<std::size_t I, class T, std::size_t N>
200EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const T& array_get(const array<T,N>& a) {
201 return a[I];
202}
203
204template <typename T> struct array_size;
205template<class T, std::size_t N> struct array_size<array<T,N> > {
206 static const size_t value = N;
207};
208template <typename T> struct array_size;
209template<class T, std::size_t N> struct array_size<array<T,N>& > {
210 static const size_t value = N;
211};
212template <typename T> struct array_size;
213template<class T, std::size_t N> struct array_size<const array<T,N> > {
214 static const size_t value = N;
215};
216template <typename T> struct array_size;
217template<class T, std::size_t N> struct array_size<const array<T,N>& > {
218 static const size_t value = N;
219};
220
221} // end namespace internal
222} // end namespace Eigen
223
224#else
225
226// The compiler supports c++11, and we're not targetting cuda: use std::array as Eigen::array
227#include <array>
228namespace Eigen {
229
230template <typename T, std::size_t N> using array = std::array<T, N>;
231
232namespace internal {
233/* std::get is only constexpr in C++14, not yet in C++11
234 * - libstdc++ from version 4.7 onwards has it nevertheless,
235 * so use that
236 * - libstdc++ older versions: use _M_instance directly
237 * - libc++ all versions so far: use __elems_ directly
238 * - all other libs: use std::get to be portable, but
239 * this may not be constexpr
240 */
241#if defined(__GLIBCXX__) && __GLIBCXX__ < 20120322
242#define STD_GET_ARR_HACK a._M_instance[I]
243#elif defined(_LIBCPP_VERSION)
244#define STD_GET_ARR_HACK a.__elems_[I]
245#else
246#define STD_GET_ARR_HACK std::template get<I, T, N>(a)
247#endif
248
249template<std::size_t I, class T, std::size_t N> constexpr inline T& array_get(std::array<T,N>& a) { return (T&) STD_GET_ARR_HACK; }
250template<std::size_t I, class T, std::size_t N> constexpr inline T&& array_get(std::array<T,N>&& a) { return (T&&) STD_GET_ARR_HACK; }
251template<std::size_t I, class T, std::size_t N> constexpr inline T const& array_get(std::array<T,N> const& a) { return (T const&) STD_GET_ARR_HACK; }
252
253#undef STD_GET_ARR_HACK
254
255template <typename T> struct array_size;
256template<class T, std::size_t N> struct array_size<const std::array<T,N> > {
257 static const size_t value = N;
258};
259template <typename T> struct array_size;
260template<class T, std::size_t N> struct array_size<std::array<T,N> > {
261 static const size_t value = N;
262};
263} // end namespace internal
264} // end namespace Eigen
265
266#endif
267
268#endif // EIGEN_EMULATE_ARRAY_H
Eigen
Namespace containing all symbols from the Eigen library.