197403Sobrien// Functional extensions -*- C++ -*- 297403Sobrien 3169691Skan// Copyright (C) 2002, 2004, 2005 Free Software Foundation, Inc. 497403Sobrien// 597403Sobrien// This file is part of the GNU ISO C++ Library. This library is free 697403Sobrien// software; you can redistribute it and/or modify it under the 797403Sobrien// terms of the GNU General Public License as published by the 897403Sobrien// Free Software Foundation; either version 2, or (at your option) 997403Sobrien// any later version. 1097403Sobrien 1197403Sobrien// This library is distributed in the hope that it will be useful, 1297403Sobrien// but WITHOUT ANY WARRANTY; without even the implied warranty of 1397403Sobrien// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 1497403Sobrien// GNU General Public License for more details. 1597403Sobrien 1697403Sobrien// You should have received a copy of the GNU General Public License along 1797403Sobrien// with this library; see the file COPYING. If not, write to the Free 18169691Skan// Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, 1997403Sobrien// USA. 2097403Sobrien 2197403Sobrien// As a special exception, you may use this file as part of a free software 2297403Sobrien// library without restriction. Specifically, if other files instantiate 2397403Sobrien// templates or use macros or inline functions from this file, or you compile 2497403Sobrien// this file and link it with other files to produce an executable, this 2597403Sobrien// file does not by itself cause the resulting executable to be covered by 2697403Sobrien// the GNU General Public License. This exception does not however 2797403Sobrien// invalidate any other reasons why the executable file might be covered by 2897403Sobrien// the GNU General Public License. 2997403Sobrien 3097403Sobrien/* 3197403Sobrien * 3297403Sobrien * Copyright (c) 1994 3397403Sobrien * Hewlett-Packard Company 3497403Sobrien * 3597403Sobrien * Permission to use, copy, modify, distribute and sell this software 3697403Sobrien * and its documentation for any purpose is hereby granted without fee, 3797403Sobrien * provided that the above copyright notice appear in all copies and 3897403Sobrien * that both that copyright notice and this permission notice appear 3997403Sobrien * in supporting documentation. Hewlett-Packard Company makes no 4097403Sobrien * representations about the suitability of this software for any 4197403Sobrien * purpose. It is provided "as is" without express or implied warranty. 4297403Sobrien * 4397403Sobrien * 4497403Sobrien * Copyright (c) 1996 4597403Sobrien * Silicon Graphics Computer Systems, Inc. 4697403Sobrien * 4797403Sobrien * Permission to use, copy, modify, distribute and sell this software 4897403Sobrien * and its documentation for any purpose is hereby granted without fee, 4997403Sobrien * provided that the above copyright notice appear in all copies and 5097403Sobrien * that both that copyright notice and this permission notice appear 5197403Sobrien * in supporting documentation. Silicon Graphics makes no 5297403Sobrien * representations about the suitability of this software for any 5397403Sobrien * purpose. It is provided "as is" without express or implied warranty. 5497403Sobrien */ 5597403Sobrien 5697403Sobrien/** @file ext/functional 5797403Sobrien * This file is a GNU extension to the Standard C++ Library (possibly 58169691Skan * containing extensions from the HP/SGI STL subset). 5997403Sobrien */ 6097403Sobrien 6197403Sobrien#ifndef _EXT_FUNCTIONAL 62132720Skan#define _EXT_FUNCTIONAL 1 6397403Sobrien 6497403Sobrien#pragma GCC system_header 65132720Skan 6697403Sobrien#include <functional> 6797403Sobrien 68169691Skan_GLIBCXX_BEGIN_NAMESPACE(__gnu_cxx) 6997403Sobrien 70169691Skan using std::size_t; 71169691Skan using std::unary_function; 72169691Skan using std::binary_function; 73169691Skan using std::mem_fun1_t; 74169691Skan using std::const_mem_fun1_t; 75169691Skan using std::mem_fun1_ref_t; 76169691Skan using std::const_mem_fun1_ref_t; 7797403Sobrien 78169691Skan /** The @c identity_element functions are not part of the C++ 79169691Skan * standard; SGI provided them as an extension. Its argument is an 80169691Skan * operation, and its return value is the identity element for that 81169691Skan * operation. It is overloaded for addition and multiplication, 82169691Skan * and you can overload it for your own nefarious operations. 83169691Skan * 84169691Skan * @addtogroup SGIextensions 85169691Skan * @{ 86169691Skan */ 87169691Skan /// An \link SGIextensions SGI extension \endlink. 88169691Skan template <class _Tp> 89169691Skan inline _Tp 90169691Skan identity_element(std::plus<_Tp>) 91169691Skan { return _Tp(0); } 9297403Sobrien 93169691Skan /// An \link SGIextensions SGI extension \endlink. 94169691Skan template <class _Tp> 95169691Skan inline _Tp 96169691Skan identity_element(std::multiplies<_Tp>) 97169691Skan { return _Tp(1); } 98169691Skan /** @} */ 99169691Skan 100169691Skan /** As an extension to the binders, SGI provided composition functors and 101169691Skan * wrapper functions to aid in their creation. The @c unary_compose 102169691Skan * functor is constructed from two functions/functors, @c f and @c g. 103169691Skan * Calling @c operator() with a single argument @c x returns @c f(g(x)). 104169691Skan * The function @c compose1 takes the two functions and constructs a 105169691Skan * @c unary_compose variable for you. 106169691Skan * 107169691Skan * @c binary_compose is constructed from three functors, @c f, @c g1, 108169691Skan * and @c g2. Its @c operator() returns @c f(g1(x),g2(x)). The function 109169691Skan * @compose2 takes f, g1, and g2, and constructs the @c binary_compose 110169691Skan * instance for you. For example, if @c f returns an int, then 111169691Skan * \code 112169691Skan * int answer = (compose2(f,g1,g2))(x); 113169691Skan * \endcode 114169691Skan * is equivalent to 115169691Skan * \code 116169691Skan * int temp1 = g1(x); 117169691Skan * int temp2 = g2(x); 118169691Skan * int answer = f(temp1,temp2); 119169691Skan * \endcode 120169691Skan * But the first form is more compact, and can be passed around as a 121169691Skan * functor to other algorithms. 122169691Skan * 123169691Skan * @addtogroup SGIextensions 124169691Skan * @{ 125169691Skan */ 126169691Skan /// An \link SGIextensions SGI extension \endlink. 127169691Skan template <class _Operation1, class _Operation2> 128169691Skan class unary_compose 129169691Skan : public unary_function<typename _Operation2::argument_type, 130169691Skan typename _Operation1::result_type> 131169691Skan { 132169691Skan protected: 133169691Skan _Operation1 _M_fn1; 134169691Skan _Operation2 _M_fn2; 13597403Sobrien 136169691Skan public: 137169691Skan unary_compose(const _Operation1& __x, const _Operation2& __y) 138169691Skan : _M_fn1(__x), _M_fn2(__y) {} 13997403Sobrien 140169691Skan typename _Operation1::result_type 141169691Skan operator()(const typename _Operation2::argument_type& __x) const 142169691Skan { return _M_fn1(_M_fn2(__x)); } 143169691Skan }; 14497403Sobrien 145169691Skan /// An \link SGIextensions SGI extension \endlink. 146169691Skan template <class _Operation1, class _Operation2> 147169691Skan inline unary_compose<_Operation1, _Operation2> 148169691Skan compose1(const _Operation1& __fn1, const _Operation2& __fn2) 149169691Skan { return unary_compose<_Operation1,_Operation2>(__fn1, __fn2); } 15097403Sobrien 151169691Skan /// An \link SGIextensions SGI extension \endlink. 152169691Skan template <class _Operation1, class _Operation2, class _Operation3> 153169691Skan class binary_compose 154169691Skan : public unary_function<typename _Operation2::argument_type, 155169691Skan typename _Operation1::result_type> 156169691Skan { 157169691Skan protected: 158169691Skan _Operation1 _M_fn1; 159169691Skan _Operation2 _M_fn2; 160169691Skan _Operation3 _M_fn3; 161169691Skan 162169691Skan public: 163169691Skan binary_compose(const _Operation1& __x, const _Operation2& __y, 164169691Skan const _Operation3& __z) 165169691Skan : _M_fn1(__x), _M_fn2(__y), _M_fn3(__z) { } 16697403Sobrien 167169691Skan typename _Operation1::result_type 168169691Skan operator()(const typename _Operation2::argument_type& __x) const 169169691Skan { return _M_fn1(_M_fn2(__x), _M_fn3(__x)); } 170169691Skan }; 17197403Sobrien 172169691Skan /// An \link SGIextensions SGI extension \endlink. 173169691Skan template <class _Operation1, class _Operation2, class _Operation3> 174169691Skan inline binary_compose<_Operation1, _Operation2, _Operation3> 175169691Skan compose2(const _Operation1& __fn1, const _Operation2& __fn2, 176169691Skan const _Operation3& __fn3) 177169691Skan { return binary_compose<_Operation1, _Operation2, _Operation3> 178169691Skan (__fn1, __fn2, __fn3); } 179169691Skan /** @} */ 18097403Sobrien 181169691Skan /** As an extension, SGI provided a functor called @c identity. When a 182169691Skan * functor is required but no operations are desired, this can be used as a 183169691Skan * pass-through. Its @c operator() returns its argument unchanged. 184169691Skan * 185169691Skan * @addtogroup SGIextensions 186169691Skan */ 187169691Skan template <class _Tp> 188169691Skan struct identity : public std::_Identity<_Tp> {}; 18997403Sobrien 190169691Skan /** @c select1st and @c select2nd are extensions provided by SGI. Their 191169691Skan * @c operator()s 192169691Skan * take a @c std::pair as an argument, and return either the first member 193169691Skan * or the second member, respectively. They can be used (especially with 194169691Skan * the composition functors) to "strip" data from a sequence before 195169691Skan * performing the remainder of an algorithm. 196169691Skan * 197169691Skan * @addtogroup SGIextensions 198169691Skan * @{ 199169691Skan */ 200169691Skan /// An \link SGIextensions SGI extension \endlink. 201169691Skan template <class _Pair> 202169691Skan struct select1st : public std::_Select1st<_Pair> {}; 20397403Sobrien 204169691Skan /// An \link SGIextensions SGI extension \endlink. 205169691Skan template <class _Pair> 206169691Skan struct select2nd : public std::_Select2nd<_Pair> {}; 207169691Skan /** @} */ 20897403Sobrien 209169691Skan // extension documented next 210169691Skan template <class _Arg1, class _Arg2> 211169691Skan struct _Project1st : public binary_function<_Arg1, _Arg2, _Arg1> 212169691Skan { 213169691Skan _Arg1 214169691Skan operator()(const _Arg1& __x, const _Arg2&) const 215169691Skan { return __x; } 216169691Skan }; 21797403Sobrien 218169691Skan template <class _Arg1, class _Arg2> 219169691Skan struct _Project2nd : public binary_function<_Arg1, _Arg2, _Arg2> 220169691Skan { 221169691Skan _Arg2 222169691Skan operator()(const _Arg1&, const _Arg2& __y) const 223169691Skan { return __y; } 224169691Skan }; 22597403Sobrien 226169691Skan /** The @c operator() of the @c project1st functor takes two arbitrary 227169691Skan * arguments and returns the first one, while @c project2nd returns the 228169691Skan * second one. They are extensions provided by SGI. 229169691Skan * 230169691Skan * @addtogroup SGIextensions 231169691Skan * @{ 232169691Skan */ 23397403Sobrien 234169691Skan /// An \link SGIextensions SGI extension \endlink. 235169691Skan template <class _Arg1, class _Arg2> 236169691Skan struct project1st : public _Project1st<_Arg1, _Arg2> {}; 23797403Sobrien 238169691Skan /// An \link SGIextensions SGI extension \endlink. 239169691Skan template <class _Arg1, class _Arg2> 240169691Skan struct project2nd : public _Project2nd<_Arg1, _Arg2> {}; 241169691Skan /** @} */ 24297403Sobrien 243169691Skan // extension documented next 244169691Skan template <class _Result> 245169691Skan struct _Constant_void_fun 246169691Skan { 247169691Skan typedef _Result result_type; 248169691Skan result_type _M_val; 24997403Sobrien 250169691Skan _Constant_void_fun(const result_type& __v) : _M_val(__v) {} 25197403Sobrien 252169691Skan const result_type& 253169691Skan operator()() const 254169691Skan { return _M_val; } 255169691Skan }; 25697403Sobrien 257169691Skan template <class _Result, class _Argument> 258169691Skan struct _Constant_unary_fun 259169691Skan { 260169691Skan typedef _Argument argument_type; 261169691Skan typedef _Result result_type; 262169691Skan result_type _M_val; 263169691Skan 264169691Skan _Constant_unary_fun(const result_type& __v) : _M_val(__v) {} 26597403Sobrien 266169691Skan const result_type& 267169691Skan operator()(const _Argument&) const 268169691Skan { return _M_val; } 269169691Skan }; 27097403Sobrien 271169691Skan template <class _Result, class _Arg1, class _Arg2> 272169691Skan struct _Constant_binary_fun 273169691Skan { 274169691Skan typedef _Arg1 first_argument_type; 275169691Skan typedef _Arg2 second_argument_type; 276169691Skan typedef _Result result_type; 277169691Skan _Result _M_val; 27897403Sobrien 279169691Skan _Constant_binary_fun(const _Result& __v) : _M_val(__v) {} 280169691Skan 281169691Skan const result_type& 282169691Skan operator()(const _Arg1&, const _Arg2&) const 283169691Skan { return _M_val; } 284169691Skan }; 28597403Sobrien 286169691Skan /** These three functors are each constructed from a single arbitrary 287169691Skan * variable/value. Later, their @c operator()s completely ignore any 288169691Skan * arguments passed, and return the stored value. 289169691Skan * - @c constant_void_fun's @c operator() takes no arguments 290169691Skan * - @c constant_unary_fun's @c operator() takes one argument (ignored) 291169691Skan * - @c constant_binary_fun's @c operator() takes two arguments (ignored) 292169691Skan * 293169691Skan * The helper creator functions @c constant0, @c constant1, and 294169691Skan * @c constant2 each take a "result" argument and construct variables of 295169691Skan * the appropriate functor type. 296169691Skan * 297169691Skan * @addtogroup SGIextensions 298169691Skan * @{ 299169691Skan */ 300169691Skan /// An \link SGIextensions SGI extension \endlink. 301169691Skan template <class _Result> 302169691Skan struct constant_void_fun 303169691Skan : public _Constant_void_fun<_Result> 304169691Skan { 305169691Skan constant_void_fun(const _Result& __v) 306169691Skan : _Constant_void_fun<_Result>(__v) {} 307169691Skan }; 30897403Sobrien 309169691Skan /// An \link SGIextensions SGI extension \endlink. 310169691Skan template <class _Result, class _Argument = _Result> 311169691Skan struct constant_unary_fun : public _Constant_unary_fun<_Result, _Argument> 312169691Skan { 313169691Skan constant_unary_fun(const _Result& __v) 314169691Skan : _Constant_unary_fun<_Result, _Argument>(__v) {} 315169691Skan }; 316169691Skan 317169691Skan /// An \link SGIextensions SGI extension \endlink. 318169691Skan template <class _Result, class _Arg1 = _Result, class _Arg2 = _Arg1> 319169691Skan struct constant_binary_fun 320169691Skan : public _Constant_binary_fun<_Result, _Arg1, _Arg2> 321169691Skan { 322169691Skan constant_binary_fun(const _Result& __v) 323169691Skan : _Constant_binary_fun<_Result, _Arg1, _Arg2>(__v) {} 324169691Skan }; 325169691Skan 326169691Skan /// An \link SGIextensions SGI extension \endlink. 327169691Skan template <class _Result> 328169691Skan inline constant_void_fun<_Result> 329169691Skan constant0(const _Result& __val) 330169691Skan { return constant_void_fun<_Result>(__val); } 331169691Skan 332169691Skan /// An \link SGIextensions SGI extension \endlink. 333169691Skan template <class _Result> 334169691Skan inline constant_unary_fun<_Result, _Result> 335169691Skan constant1(const _Result& __val) 336169691Skan { return constant_unary_fun<_Result, _Result>(__val); } 337169691Skan 338169691Skan /// An \link SGIextensions SGI extension \endlink. 339169691Skan template <class _Result> 340169691Skan inline constant_binary_fun<_Result,_Result,_Result> 341169691Skan constant2(const _Result& __val) 342169691Skan { return constant_binary_fun<_Result, _Result, _Result>(__val); } 343169691Skan /** @} */ 344169691Skan 345169691Skan /** The @c subtractive_rng class is documented on 346169691Skan * <a href="http://www.sgi.com/tech/stl/">SGI's site</a>. 347169691Skan * Note that this code assumes that @c int is 32 bits. 348169691Skan * 349169691Skan * @ingroup SGIextensions 350169691Skan */ 351169691Skan class subtractive_rng 352169691Skan : public unary_function<unsigned int, unsigned int> 35397403Sobrien { 354169691Skan private: 355169691Skan unsigned int _M_table[55]; 356169691Skan size_t _M_index1; 357169691Skan size_t _M_index2; 358169691Skan 359169691Skan public: 360169691Skan /// Returns a number less than the argument. 361169691Skan unsigned int 362169691Skan operator()(unsigned int __limit) 363169691Skan { 364169691Skan _M_index1 = (_M_index1 + 1) % 55; 365169691Skan _M_index2 = (_M_index2 + 1) % 55; 366169691Skan _M_table[_M_index1] = _M_table[_M_index1] - _M_table[_M_index2]; 367169691Skan return _M_table[_M_index1] % __limit; 36897403Sobrien } 369169691Skan 370169691Skan void 371169691Skan _M_initialize(unsigned int __seed) 372169691Skan { 373169691Skan unsigned int __k = 1; 374169691Skan _M_table[54] = __seed; 375169691Skan size_t __i; 376169691Skan for (__i = 0; __i < 54; __i++) 377169691Skan { 378169691Skan size_t __ii = (21 * (__i + 1) % 55) - 1; 379169691Skan _M_table[__ii] = __k; 380169691Skan __k = __seed - __k; 381169691Skan __seed = _M_table[__ii]; 382169691Skan } 383169691Skan for (int __loop = 0; __loop < 4; __loop++) 384169691Skan { 385169691Skan for (__i = 0; __i < 55; __i++) 38697403Sobrien _M_table[__i] = _M_table[__i] - _M_table[(1 + __i + 30) % 55]; 387169691Skan } 388169691Skan _M_index1 = 0; 389169691Skan _M_index2 = 31; 39097403Sobrien } 39197403Sobrien 392169691Skan /// Ctor allowing you to initialize the seed. 393169691Skan subtractive_rng(unsigned int __seed) 394169691Skan { _M_initialize(__seed); } 39597403Sobrien 396169691Skan /// Default ctor; initializes its state with some number you don't see. 397169691Skan subtractive_rng() 398169691Skan { _M_initialize(161803398u); } 399169691Skan }; 40097403Sobrien 401169691Skan // Mem_fun adaptor helper functions mem_fun1 and mem_fun1_ref, 402169691Skan // provided for backward compatibility, they are no longer part of 403169691Skan // the C++ standard. 404169691Skan 405169691Skan template <class _Ret, class _Tp, class _Arg> 406169691Skan inline mem_fun1_t<_Ret, _Tp, _Arg> 407169691Skan mem_fun1(_Ret (_Tp::*__f)(_Arg)) 408169691Skan { return mem_fun1_t<_Ret, _Tp, _Arg>(__f); } 40997403Sobrien 410169691Skan template <class _Ret, class _Tp, class _Arg> 411169691Skan inline const_mem_fun1_t<_Ret, _Tp, _Arg> 412169691Skan mem_fun1(_Ret (_Tp::*__f)(_Arg) const) 413169691Skan { return const_mem_fun1_t<_Ret, _Tp, _Arg>(__f); } 41497403Sobrien 415169691Skan template <class _Ret, class _Tp, class _Arg> 416169691Skan inline mem_fun1_ref_t<_Ret, _Tp, _Arg> 417169691Skan mem_fun1_ref(_Ret (_Tp::*__f)(_Arg)) 418169691Skan { return mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); } 41997403Sobrien 420169691Skan template <class _Ret, class _Tp, class _Arg> 421169691Skan inline const_mem_fun1_ref_t<_Ret, _Tp, _Arg> 422169691Skan mem_fun1_ref(_Ret (_Tp::*__f)(_Arg) const) 423169691Skan { return const_mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); } 42497403Sobrien 425169691Skan_GLIBCXX_END_NAMESPACE 426169691Skan 427132720Skan#endif 42897403Sobrien 429