1 // -*- C++ -*- 2 3 // Copyright (C) 2007-2013 Free Software Foundation, Inc. 4 // 5 // This file is part of the GNU ISO C++ Library. This library is free 6 // software; you can redistribute it and/or modify it under the terms 7 // of the GNU General Public License as published by the Free Software 8 // Foundation; either version 3, or (at your option) any later 9 // version. 10 11 // This library is distributed in the hope that it will be useful, but 12 // WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 14 // General Public License for more details. 15 16 // Under Section 7 of GPL version 3, you are granted additional 17 // permissions described in the GCC Runtime Library Exception, version 18 // 3.1, as published by the Free Software Foundation. 19 20 // You should have received a copy of the GNU General Public License and 21 // a copy of the GCC Runtime Library Exception along with this program; 22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see 23 // <http://www.gnu.org/licenses/>. 24 25 /** @file parallel/for_each_selectors.h 26 * @brief Functors representing different tasks to be plugged into the 27 * generic parallelization methods for embarrassingly parallel functions. 28 * This file is a GNU parallel extension to the Standard C++ Library. 29 */ 30 31 // Written by Felix Putze. 32 33 #ifndef _GLIBCXX_PARALLEL_FOR_EACH_SELECTORS_H 34 #define _GLIBCXX_PARALLEL_FOR_EACH_SELECTORS_H 1 35 36 #include <parallel/basic_iterator.h> 37 38 namespace __gnu_parallel 39 { 40 /** @brief Generic __selector for embarrassingly parallel functions. */ 41 template<typename _It> 42 struct __generic_for_each_selector 43 { 44 /** @brief _Iterator on last element processed; needed for some 45 * algorithms (e. g. std::transform()). 46 */ 47 _It _M_finish_iterator; 48 }; 49 50 /** @brief std::for_each() selector. */ 51 template<typename _It> 52 struct __for_each_selector : public __generic_for_each_selector<_It> 53 { 54 /** @brief Functor execution. 55 * @param __o Operator. 56 * @param __i iterator referencing object. */ 57 template<typename _Op> 58 bool 59 operator()(_Op& __o, _It __i) 60 { 61 __o(*__i); 62 return true; 63 } 64 }; 65 66 /** @brief std::generate() selector. */ 67 template<typename _It> 68 struct __generate_selector : public __generic_for_each_selector<_It> 69 { 70 /** @brief Functor execution. 71 * @param __o Operator. 72 * @param __i iterator referencing object. */ 73 template<typename _Op> 74 bool 75 operator()(_Op& __o, _It __i) 76 { 77 *__i = __o(); 78 return true; 79 } 80 }; 81 82 /** @brief std::fill() selector. */ 83 template<typename _It> 84 struct __fill_selector : public __generic_for_each_selector<_It> 85 { 86 /** @brief Functor execution. 87 * @param __v Current value. 88 * @param __i iterator referencing object. */ 89 template<typename _ValueType> 90 bool 91 operator()(_ValueType& __v, _It __i) 92 { 93 *__i = __v; 94 return true; 95 } 96 }; 97 98 /** @brief std::transform() __selector, one input sequence variant. */ 99 template<typename _It> 100 struct __transform1_selector : public __generic_for_each_selector<_It> 101 { 102 /** @brief Functor execution. 103 * @param __o Operator. 104 * @param __i iterator referencing object. */ 105 template<typename _Op> 106 bool 107 operator()(_Op& __o, _It __i) 108 { 109 *__i.second = __o(*__i.first); 110 return true; 111 } 112 }; 113 114 /** @brief std::transform() __selector, two input sequences variant. */ 115 template<typename _It> 116 struct __transform2_selector : public __generic_for_each_selector<_It> 117 { 118 /** @brief Functor execution. 119 * @param __o Operator. 120 * @param __i iterator referencing object. */ 121 template<typename _Op> 122 bool 123 operator()(_Op& __o, _It __i) 124 { 125 *__i._M_third = __o(*__i._M_first, *__i._M_second); 126 return true; 127 } 128 }; 129 130 /** @brief std::replace() selector. */ 131 template<typename _It, typename _Tp> 132 struct __replace_selector : public __generic_for_each_selector<_It> 133 { 134 /** @brief Value to replace with. */ 135 const _Tp& __new_val; 136 137 /** @brief Constructor 138 * @param __new_val Value to replace with. */ 139 explicit 140 __replace_selector(const _Tp &__new_val) : __new_val(__new_val) {} 141 142 /** @brief Functor execution. 143 * @param __v Current value. 144 * @param __i iterator referencing object. */ 145 bool 146 operator()(_Tp& __v, _It __i) 147 { 148 if (*__i == __v) 149 *__i = __new_val; 150 return true; 151 } 152 }; 153 154 /** @brief std::replace() selector. */ 155 template<typename _It, typename _Op, typename _Tp> 156 struct __replace_if_selector : public __generic_for_each_selector<_It> 157 { 158 /** @brief Value to replace with. */ 159 const _Tp& __new_val; 160 161 /** @brief Constructor. 162 * @param __new_val Value to replace with. */ 163 explicit 164 __replace_if_selector(const _Tp &__new_val) : __new_val(__new_val) { } 165 166 /** @brief Functor execution. 167 * @param __o Operator. 168 * @param __i iterator referencing object. */ 169 bool 170 operator()(_Op& __o, _It __i) 171 { 172 if (__o(*__i)) 173 *__i = __new_val; 174 return true; 175 } 176 }; 177 178 /** @brief std::count() selector. */ 179 template<typename _It, typename _Diff> 180 struct __count_selector : public __generic_for_each_selector<_It> 181 { 182 /** @brief Functor execution. 183 * @param __v Current value. 184 * @param __i iterator referencing object. 185 * @return 1 if count, 0 if does not count. */ 186 template<typename _ValueType> 187 _Diff 188 operator()(_ValueType& __v, _It __i) 189 { return (__v == *__i) ? 1 : 0; } 190 }; 191 192 /** @brief std::count_if () selector. */ 193 template<typename _It, typename _Diff> 194 struct __count_if_selector : public __generic_for_each_selector<_It> 195 { 196 /** @brief Functor execution. 197 * @param __o Operator. 198 * @param __i iterator referencing object. 199 * @return 1 if count, 0 if does not count. */ 200 template<typename _Op> 201 _Diff 202 operator()(_Op& __o, _It __i) 203 { return (__o(*__i)) ? 1 : 0; } 204 }; 205 206 /** @brief std::accumulate() selector. */ 207 template<typename _It> 208 struct __accumulate_selector : public __generic_for_each_selector<_It> 209 { 210 /** @brief Functor execution. 211 * @param __o Operator (unused). 212 * @param __i iterator referencing object. 213 * @return The current value. */ 214 template<typename _Op> 215 typename std::iterator_traits<_It>::value_type 216 operator()(_Op __o, _It __i) 217 { return *__i; } 218 }; 219 220 /** @brief std::inner_product() selector. */ 221 template<typename _It, typename _It2, typename _Tp> 222 struct __inner_product_selector : public __generic_for_each_selector<_It> 223 { 224 /** @brief Begin iterator of first sequence. */ 225 _It __begin1_iterator; 226 227 /** @brief Begin iterator of second sequence. */ 228 _It2 __begin2_iterator; 229 230 /** @brief Constructor. 231 * @param __b1 Begin iterator of first sequence. 232 * @param __b2 Begin iterator of second sequence. */ 233 explicit 234 __inner_product_selector(_It __b1, _It2 __b2) 235 : __begin1_iterator(__b1), __begin2_iterator(__b2) { } 236 237 /** @brief Functor execution. 238 * @param __mult Multiplication functor. 239 * @param __current iterator referencing object. 240 * @return Inner product elemental __result. */ 241 template<typename _Op> 242 _Tp 243 operator()(_Op __mult, _It __current) 244 { 245 typename std::iterator_traits<_It>::difference_type __position 246 = __current - __begin1_iterator; 247 return __mult(*__current, *(__begin2_iterator + __position)); 248 } 249 }; 250 251 /** @brief Selector that just returns the passed iterator. */ 252 template<typename _It> 253 struct __identity_selector : public __generic_for_each_selector<_It> 254 { 255 /** @brief Functor execution. 256 * @param __o Operator (unused). 257 * @param __i iterator referencing object. 258 * @return Passed iterator. */ 259 template<typename _Op> 260 _It 261 operator()(_Op __o, _It __i) 262 { return __i; } 263 }; 264 265 /** @brief Selector that returns the difference between two adjacent 266 * __elements. 267 */ 268 template<typename _It> 269 struct __adjacent_difference_selector 270 : public __generic_for_each_selector<_It> 271 { 272 template<typename _Op> 273 bool 274 operator()(_Op& __o, _It __i) 275 { 276 typename _It::first_type __go_back_one = __i.first; 277 --__go_back_one; 278 *__i.second = __o(*__i.first, *__go_back_one); 279 return true; 280 } 281 }; 282 283 /** @brief Functor doing nothing 284 * 285 * For some __reduction tasks (this is not a function object, but is 286 * passed as __selector __dummy parameter. 287 */ 288 struct _Nothing 289 { 290 /** @brief Functor execution. 291 * @param __i iterator referencing object. */ 292 template<typename _It> 293 void 294 operator()(_It __i) { } 295 }; 296 297 /** @brief Reduction function doing nothing. */ 298 struct _DummyReduct 299 { 300 bool 301 operator()(bool, bool) const 302 { return true; } 303 }; 304 305 /** @brief Reduction for finding the maximum element, using a comparator. */ 306 template<typename _Compare, typename _It> 307 struct __min_element_reduct 308 { 309 _Compare& __comp; 310 311 explicit 312 __min_element_reduct(_Compare &__c) : __comp(__c) { } 313 314 _It 315 operator()(_It __x, _It __y) 316 { return (__comp(*__x, *__y)) ? __x : __y; } 317 }; 318 319 /** @brief Reduction for finding the maximum element, using a comparator. */ 320 template<typename _Compare, typename _It> 321 struct __max_element_reduct 322 { 323 _Compare& __comp; 324 325 explicit 326 __max_element_reduct(_Compare& __c) : __comp(__c) { } 327 328 _It 329 operator()(_It __x, _It __y) 330 { return (__comp(*__x, *__y)) ? __y : __x; } 331 }; 332 333 /** @brief General reduction, using a binary operator. */ 334 template<typename _BinOp> 335 struct __accumulate_binop_reduct 336 { 337 _BinOp& __binop; 338 339 explicit 340 __accumulate_binop_reduct(_BinOp& __b) : __binop(__b) { } 341 342 template<typename _Result, typename _Addend> 343 _Result 344 operator()(const _Result& __x, const _Addend& __y) 345 { return __binop(__x, __y); } 346 }; 347 } 348 349 #endif /* _GLIBCXX_PARALLEL_FOR_EACH_SELECTORS_H */ 350
