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The C and C++ Include Header Files
cat -n /usr/include/c++/15/ext/functional
1 // Functional extensions -*- C++ -*- 2 3 // Copyright (C) 2002-2025 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 7 // terms of the GNU General Public License as published by the 8 // Free Software Foundation; either version 3, or (at your option) 9 // any later version. 10 11 // This library is distributed in the hope that it will be useful, 12 // but WITHOUT ANY WARRANTY; without even the implied warranty of 13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 14 // GNU 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 /* 26 * 27 * Copyright (c) 1994 28 * Hewlett-Packard Company 29 * 30 * Permission to use, copy, modify, distribute and sell this software 31 * and its documentation for any purpose is hereby granted without fee, 32 * provided that the above copyright notice appear in all copies and 33 * that both that copyright notice and this permission notice appear 34 * in supporting documentation. Hewlett-Packard Company makes no 35 * representations about the suitability of this software for any 36 * purpose. It is provided "as is" without express or implied warranty. 37 * 38 * 39 * Copyright (c) 1996 40 * Silicon Graphics Computer Systems, Inc. 41 * 42 * Permission to use, copy, modify, distribute and sell this software 43 * and its documentation for any purpose is hereby granted without fee, 44 * provided that the above copyright notice appear in all copies and 45 * that both that copyright notice and this permission notice appear 46 * in supporting documentation. Silicon Graphics makes no 47 * representations about the suitability of this software for any 48 * purpose. It is provided "as is" without express or implied warranty. 49 */ 50 51 /** @file ext/functional 52 * This file is a GNU extension to the Standard C++ Library (possibly 53 * containing extensions from the HP/SGI STL subset). 54 */ 55 56 #ifndef _EXT_FUNCTIONAL 57 #define _EXT_FUNCTIONAL 1 58 59 #ifdef _GLIBCXX_SYSHDR 60 #pragma GCC system_header 61 #endif 62 63 #include <bits/requires_hosted.h> // GNU extensions are currently omitted 64 65 #include <functional> 66 67 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) 68 { 69 _GLIBCXX_BEGIN_NAMESPACE_VERSION 70 71 #pragma GCC diagnostic push 72 #pragma GCC diagnostic ignored "-Wdeprecated-declarations" 73 74 /** The @c identity_element functions are not part of the C++ 75 * standard; SGI provided them as an extension. Its argument is an 76 * operation, and its return value is the identity element for that 77 * operation. It is overloaded for addition and multiplication, 78 * and you can overload it for your own nefarious operations. 79 * 80 * @addtogroup SGIextensions 81 * @{ 82 */ 83 /// An \link SGIextensions SGI extension \endlink. 84 template <class _Tp> 85 inline _Tp 86 identity_element(std::plus<_Tp>) 87 { return _Tp(0); } 88 89 /// An \link SGIextensions SGI extension \endlink. 90 template <class _Tp> 91 inline _Tp 92 identity_element(std::multiplies<_Tp>) 93 { return _Tp(1); } 94 /** @} */ 95 96 /** As an extension to the binders, SGI provided composition functors and 97 * wrapper functions to aid in their creation. The @c unary_compose 98 * functor is constructed from two functions/functors, @c f and @c g. 99 * Calling @c operator() with a single argument @c x returns @c f(g(x)). 100 * The function @c compose1 takes the two functions and constructs a 101 * @c unary_compose variable for you. 102 * 103 * @c binary_compose is constructed from three functors, @c f, @c g1, 104 * and @c g2. Its @c operator() returns @c f(g1(x),g2(x)). The function 105 * compose2 takes f, g1, and g2, and constructs the @c binary_compose 106 * instance for you. For example, if @c f returns an int, then 107 * \code 108 * int answer = (compose2(f,g1,g2))(x); 109 * \endcode 110 * is equivalent to 111 * \code 112 * int temp1 = g1(x); 113 * int temp2 = g2(x); 114 * int answer = f(temp1,temp2); 115 * \endcode 116 * But the first form is more compact, and can be passed around as a 117 * functor to other algorithms. 118 * 119 * @addtogroup SGIextensions 120 * @{ 121 */ 122 /// An \link SGIextensions SGI extension \endlink. 123 template <class _Operation1, class _Operation2> 124 class unary_compose 125 : public std::unary_function<typename _Operation2::argument_type, 126 typename _Operation1::result_type> 127 { 128 protected: 129 _Operation1 _M_fn1; 130 _Operation2 _M_fn2; 131 132 public: 133 unary_compose(const _Operation1& __x, const _Operation2& __y) 134 : _M_fn1(__x), _M_fn2(__y) {} 135 136 typename _Operation1::result_type 137 operator()(const typename _Operation2::argument_type& __x) const 138 { return _M_fn1(_M_fn2(__x)); } 139 }; 140 141 /// An \link SGIextensions SGI extension \endlink. 142 template <class _Operation1, class _Operation2> 143 inline unary_compose<_Operation1, _Operation2> 144 compose1(const _Operation1& __fn1, const _Operation2& __fn2) 145 { return unary_compose<_Operation1,_Operation2>(__fn1, __fn2); } 146 147 /// An \link SGIextensions SGI extension \endlink. 148 template <class _Operation1, class _Operation2, class _Operation3> 149 class binary_compose 150 : public std::unary_function<typename _Operation2::argument_type, 151 typename _Operation1::result_type> 152 { 153 protected: 154 _Operation1 _M_fn1; 155 _Operation2 _M_fn2; 156 _Operation3 _M_fn3; 157 158 public: 159 binary_compose(const _Operation1& __x, const _Operation2& __y, 160 const _Operation3& __z) 161 : _M_fn1(__x), _M_fn2(__y), _M_fn3(__z) { } 162 163 typename _Operation1::result_type 164 operator()(const typename _Operation2::argument_type& __x) const 165 { return _M_fn1(_M_fn2(__x), _M_fn3(__x)); } 166 }; 167 168 /// An \link SGIextensions SGI extension \endlink. 169 template <class _Operation1, class _Operation2, class _Operation3> 170 inline binary_compose<_Operation1, _Operation2, _Operation3> 171 compose2(const _Operation1& __fn1, const _Operation2& __fn2, 172 const _Operation3& __fn3) 173 { return binary_compose<_Operation1, _Operation2, _Operation3> 174 (__fn1, __fn2, __fn3); } 175 /** @} */ 176 177 /** As an extension, SGI provided a functor called @c identity. When a 178 * functor is required but no operations are desired, this can be used as a 179 * pass-through. Its @c operator() returns its argument unchanged. 180 * 181 * @addtogroup SGIextensions 182 */ 183 template <class _Tp> 184 struct identity 185 : public std::_Identity<_Tp> {}; 186 187 /** @c select1st and @c select2nd are extensions provided by SGI. Their 188 * @c operator()s 189 * take a @c std::pair as an argument, and return either the first member 190 * or the second member, respectively. They can be used (especially with 191 * the composition functors) to @a strip data from a sequence before 192 * performing the remainder of an algorithm. 193 * 194 * @addtogroup SGIextensions 195 * @{ 196 */ 197 /// An \link SGIextensions SGI extension \endlink. 198 template <class _Pair> 199 struct select1st 200 : public std::_Select1st<_Pair> {}; 201 202 /// An \link SGIextensions SGI extension \endlink. 203 template <class _Pair> 204 struct select2nd 205 : public std::_Select2nd<_Pair> {}; 206 207 /** @} */ 208 209 // extension documented next 210 template <class _Arg1, class _Arg2> 211 struct _Project1st : public std::binary_function<_Arg1, _Arg2, _Arg1> 212 { 213 _Arg1 214 operator()(const _Arg1& __x, const _Arg2&) const 215 { return __x; } 216 }; 217 218 template <class _Arg1, class _Arg2> 219 struct _Project2nd : public std::binary_function<_Arg1, _Arg2, _Arg2> 220 { 221 _Arg2 222 operator()(const _Arg1&, const _Arg2& __y) const 223 { return __y; } 224 }; 225 226 /** The @c operator() of the @c project1st functor takes two arbitrary 227 * arguments and returns the first one, while @c project2nd returns the 228 * second one. They are extensions provided by SGI. 229 * 230 * @addtogroup SGIextensions 231 * @{ 232 */ 233 234 /// An \link SGIextensions SGI extension \endlink. 235 template <class _Arg1, class _Arg2> 236 struct project1st : public _Project1st<_Arg1, _Arg2> {}; 237 238 /// An \link SGIextensions SGI extension \endlink. 239 template <class _Arg1, class _Arg2> 240 struct project2nd : public _Project2nd<_Arg1, _Arg2> {}; 241 /** @} */ 242 243 // extension documented next 244 template <class _Result> 245 struct _Constant_void_fun 246 { 247 typedef _Result result_type; 248 result_type _M_val; 249 250 _Constant_void_fun(const result_type& __v) : _M_val(__v) {} 251 252 const result_type& 253 operator()() const 254 { return _M_val; } 255 }; 256 257 template <class _Result, class _Argument> 258 struct _Constant_unary_fun 259 { 260 typedef _Argument argument_type; 261 typedef _Result result_type; 262 result_type _M_val; 263 264 _Constant_unary_fun(const result_type& __v) : _M_val(__v) {} 265 266 const result_type& 267 operator()(const _Argument&) const 268 { return _M_val; } 269 }; 270 271 template <class _Result, class _Arg1, class _Arg2> 272 struct _Constant_binary_fun 273 { 274 typedef _Arg1 first_argument_type; 275 typedef _Arg2 second_argument_type; 276 typedef _Result result_type; 277 _Result _M_val; 278 279 _Constant_binary_fun(const _Result& __v) : _M_val(__v) {} 280 281 const result_type& 282 operator()(const _Arg1&, const _Arg2&) const 283 { return _M_val; } 284 }; 285 286 /** These three functors are each constructed from a single arbitrary 287 * variable/value. Later, their @c operator()s completely ignore any 288 * arguments passed, and return the stored value. 289 * - @c constant_void_fun's @c operator() takes no arguments 290 * - @c constant_unary_fun's @c operator() takes one argument (ignored) 291 * - @c constant_binary_fun's @c operator() takes two arguments (ignored) 292 * 293 * The helper creator functions @c constant0, @c constant1, and 294 * @c constant2 each take a @a result argument and construct variables of 295 * the appropriate functor type. 296 * 297 * @addtogroup SGIextensions 298 * @{ 299 */ 300 /// An \link SGIextensions SGI extension \endlink. 301 template <class _Result> 302 struct constant_void_fun 303 : public _Constant_void_fun<_Result> 304 { 305 constant_void_fun(const _Result& __v) 306 : _Constant_void_fun<_Result>(__v) {} 307 }; 308 309 /// An \link SGIextensions SGI extension \endlink. 310 template <class _Result, class _Argument = _Result> 311 struct constant_unary_fun : public _Constant_unary_fun<_Result, _Argument> 312 { 313 constant_unary_fun(const _Result& __v) 314 : _Constant_unary_fun<_Result, _Argument>(__v) {} 315 }; 316 317 /// An \link SGIextensions SGI extension \endlink. 318 template <class _Result, class _Arg1 = _Result, class _Arg2 = _Arg1> 319 struct constant_binary_fun 320 : public _Constant_binary_fun<_Result, _Arg1, _Arg2> 321 { 322 constant_binary_fun(const _Result& __v) 323 : _Constant_binary_fun<_Result, _Arg1, _Arg2>(__v) {} 324 }; 325 326 /// An \link SGIextensions SGI extension \endlink. 327 template <class _Result> 328 inline constant_void_fun<_Result> 329 constant0(const _Result& __val) 330 { return constant_void_fun<_Result>(__val); } 331 332 /// An \link SGIextensions SGI extension \endlink. 333 template <class _Result> 334 inline constant_unary_fun<_Result, _Result> 335 constant1(const _Result& __val) 336 { return constant_unary_fun<_Result, _Result>(__val); } 337 338 /// An \link SGIextensions SGI extension \endlink. 339 template <class _Result> 340 inline constant_binary_fun<_Result,_Result,_Result> 341 constant2(const _Result& __val) 342 { return constant_binary_fun<_Result, _Result, _Result>(__val); } 343 /** @} */ 344 345 /** The @c subtractive_rng class is documented on 346 * <a href="http://www.sgi.com/tech/stl/">SGI's site</a>. 347 * Note that this code assumes that @c int is 32 bits. 348 * 349 * @ingroup SGIextensions 350 */ 351 class subtractive_rng 352 : public std::unary_function<unsigned int, unsigned int> 353 { 354 private: 355 unsigned int _M_table[55]; 356 std::size_t _M_index1; 357 std::size_t _M_index2; 358 359 public: 360 /// Returns a number less than the argument. 361 unsigned int 362 operator()(unsigned int __limit) 363 { 364 _M_index1 = (_M_index1 + 1) % 55; 365 _M_index2 = (_M_index2 + 1) % 55; 366 _M_table[_M_index1] = _M_table[_M_index1] - _M_table[_M_index2]; 367 return _M_table[_M_index1] % __limit; 368 } 369 370 void 371 _M_initialize(unsigned int __seed) 372 { 373 unsigned int __k = 1; 374 _M_table[54] = __seed; 375 std::size_t __i; 376 for (__i = 0; __i < 54; __i++) 377 { 378 std::size_t __ii = (21 * (__i + 1) % 55) - 1; 379 _M_table[__ii] = __k; 380 __k = __seed - __k; 381 __seed = _M_table[__ii]; 382 } 383 for (int __loop = 0; __loop < 4; __loop++) 384 { 385 for (__i = 0; __i < 55; __i++) 386 _M_table[__i] = _M_table[__i] - _M_table[(1 + __i + 30) % 55]; 387 } 388 _M_index1 = 0; 389 _M_index2 = 31; 390 } 391 392 /// Ctor allowing you to initialize the seed. 393 subtractive_rng(unsigned int __seed) 394 { _M_initialize(__seed); } 395 396 /// Default ctor; initializes its state with some number you don't see. 397 subtractive_rng() 398 { _M_initialize(161803398u); } 399 }; 400 401 // Mem_fun adaptor helper functions mem_fun1 and mem_fun1_ref, 402 // provided for backward compatibility, they are no longer part of 403 // the C++ standard. 404 405 template <class _Ret, class _Tp, class _Arg> 406 inline std::mem_fun1_t<_Ret, _Tp, _Arg> 407 mem_fun1(_Ret (_Tp::*__f)(_Arg)) 408 { return std::mem_fun1_t<_Ret, _Tp, _Arg>(__f); } 409 410 template <class _Ret, class _Tp, class _Arg> 411 inline std::const_mem_fun1_t<_Ret, _Tp, _Arg> 412 mem_fun1(_Ret (_Tp::*__f)(_Arg) const) 413 { return std::const_mem_fun1_t<_Ret, _Tp, _Arg>(__f); } 414 415 template <class _Ret, class _Tp, class _Arg> 416 inline std::mem_fun1_ref_t<_Ret, _Tp, _Arg> 417 mem_fun1_ref(_Ret (_Tp::*__f)(_Arg)) 418 { return std::mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); } 419 420 template <class _Ret, class _Tp, class _Arg> 421 inline std::const_mem_fun1_ref_t<_Ret, _Tp, _Arg> 422 mem_fun1_ref(_Ret (_Tp::*__f)(_Arg) const) 423 { return std::const_mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); } 424 425 #pragma GCC diagnostic pop 426 427 _GLIBCXX_END_NAMESPACE_VERSION 428 } // namespace 429 430 #endif 431
