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// Functional extensions -*- C++ -*- |
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|
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// Copyright (C) 2002-2021 Free Software Foundation, Inc. |
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// |
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// This file is part of the GNU ISO C++ Library. This library is free |
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// software; you can redistribute it and/or modify it under the |
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// terms of the GNU General Public License as published by the |
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// Free Software Foundation; either version 3, or (at your option) |
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// any later version. |
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|
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// This library is distributed in the hope that it will be useful, |
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// but WITHOUT ANY WARRANTY; without even the implied warranty of |
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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// GNU General Public License for more details. |
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|
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// Under Section 7 of GPL version 3, you are granted additional |
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// permissions described in the GCC Runtime Library Exception, version |
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// 3.1, as published by the Free Software Foundation. |
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|
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// You should have received a copy of the GNU General Public License and |
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// a copy of the GCC Runtime Library Exception along with this program; |
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// see the files COPYING3 and COPYING.RUNTIME respectively. If not, see |
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// <http://www.gnu.org/licenses/>. |
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|
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/* |
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* |
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* Copyright (c) 1994 |
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* Hewlett-Packard Company |
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* |
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* Permission to use, copy, modify, distribute and sell this software |
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* and its documentation for any purpose is hereby granted without fee, |
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* provided that the above copyright notice appear in all copies and |
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* that both that copyright notice and this permission notice appear |
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* in supporting documentation. Hewlett-Packard Company makes no |
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* representations about the suitability of this software for any |
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* purpose. It is provided "as is" without express or implied warranty. |
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* |
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* |
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* Copyright (c) 1996 |
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* Silicon Graphics Computer Systems, Inc. |
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* |
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* Permission to use, copy, modify, distribute and sell this software |
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* and its documentation for any purpose is hereby granted without fee, |
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* provided that the above copyright notice appear in all copies and |
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* that both that copyright notice and this permission notice appear |
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* in supporting documentation. Silicon Graphics makes no |
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* representations about the suitability of this software for any |
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* purpose. It is provided "as is" without express or implied warranty. |
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*/ |
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|
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/** @file ext/functional |
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* This file is a GNU extension to the Standard C++ Library (possibly |
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* containing extensions from the HP/SGI STL subset). |
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*/ |
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|
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#ifndef _EXT_FUNCTIONAL |
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#define _EXT_FUNCTIONAL 1 |
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|
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#pragma GCC system_header |
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|
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#include <functional> |
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|
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namespace __gnu_cxx _GLIBCXX_VISIBILITY(default) |
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{ |
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_GLIBCXX_BEGIN_NAMESPACE_VERSION |
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|
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/** The @c identity_element functions are not part of the C++ |
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* standard; SGI provided them as an extension. Its argument is an |
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* operation, and its return value is the identity element for that |
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* operation. It is overloaded for addition and multiplication, |
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* and you can overload it for your own nefarious operations. |
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* |
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* @addtogroup SGIextensions |
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* @{ |
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*/ |
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Tp> |
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inline _Tp |
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identity_element(std::plus<_Tp>) |
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{ return _Tp(0); } |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Tp> |
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inline _Tp |
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identity_element(std::multiplies<_Tp>) |
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{ return _Tp(1); } |
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/** @} */ |
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|
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/** As an extension to the binders, SGI provided composition functors and |
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* wrapper functions to aid in their creation. The @c unary_compose |
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* functor is constructed from two functions/functors, @c f and @c g. |
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* Calling @c operator() with a single argument @c x returns @c f(g(x)). |
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* The function @c compose1 takes the two functions and constructs a |
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* @c unary_compose variable for you. |
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* |
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* @c binary_compose is constructed from three functors, @c f, @c g1, |
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* and @c g2. Its @c operator() returns @c f(g1(x),g2(x)). The function |
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* compose2 takes f, g1, and g2, and constructs the @c binary_compose |
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* instance for you. For example, if @c f returns an int, then |
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* \code |
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* int answer = (compose2(f,g1,g2))(x); |
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* \endcode |
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* is equivalent to |
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* \code |
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* int temp1 = g1(x); |
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* int temp2 = g2(x); |
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* int answer = f(temp1,temp2); |
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* \endcode |
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* But the first form is more compact, and can be passed around as a |
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* functor to other algorithms. |
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* |
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* @addtogroup SGIextensions |
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* @{ |
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*/ |
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Operation1, class _Operation2> |
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class unary_compose |
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: public std::unary_function<typename _Operation2::argument_type, |
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typename _Operation1::result_type> |
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{ |
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protected: |
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_Operation1 _M_fn1; |
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_Operation2 _M_fn2; |
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|
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public: |
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unary_compose(const _Operation1& __x, const _Operation2& __y) |
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: _M_fn1(__x), _M_fn2(__y) {} |
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|
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typename _Operation1::result_type |
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operator()(const typename _Operation2::argument_type& __x) const |
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{ return _M_fn1(_M_fn2(__x)); } |
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}; |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Operation1, class _Operation2> |
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inline unary_compose<_Operation1, _Operation2> |
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compose1(const _Operation1& __fn1, const _Operation2& __fn2) |
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{ return unary_compose<_Operation1,_Operation2>(__fn1, __fn2); } |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Operation1, class _Operation2, class _Operation3> |
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class binary_compose |
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: public std::unary_function<typename _Operation2::argument_type, |
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typename _Operation1::result_type> |
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{ |
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protected: |
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_Operation1 _M_fn1; |
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_Operation2 _M_fn2; |
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_Operation3 _M_fn3; |
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|
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public: |
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binary_compose(const _Operation1& __x, const _Operation2& __y, |
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const _Operation3& __z) |
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: _M_fn1(__x), _M_fn2(__y), _M_fn3(__z) { } |
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|
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typename _Operation1::result_type |
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operator()(const typename _Operation2::argument_type& __x) const |
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{ return _M_fn1(_M_fn2(__x), _M_fn3(__x)); } |
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}; |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Operation1, class _Operation2, class _Operation3> |
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inline binary_compose<_Operation1, _Operation2, _Operation3> |
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compose2(const _Operation1& __fn1, const _Operation2& __fn2, |
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const _Operation3& __fn3) |
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{ return binary_compose<_Operation1, _Operation2, _Operation3> |
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(__fn1, __fn2, __fn3); } |
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/** @} */ |
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|
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/** As an extension, SGI provided a functor called @c identity. When a |
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* functor is required but no operations are desired, this can be used as a |
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* pass-through. Its @c operator() returns its argument unchanged. |
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* |
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* @addtogroup SGIextensions |
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*/ |
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template <class _Tp> |
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struct identity |
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: public std::_Identity<_Tp> {}; |
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|
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/** @c select1st and @c select2nd are extensions provided by SGI. Their |
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* @c operator()s |
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* take a @c std::pair as an argument, and return either the first member |
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* or the second member, respectively. They can be used (especially with |
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* the composition functors) to @a strip data from a sequence before |
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* performing the remainder of an algorithm. |
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* |
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* @addtogroup SGIextensions |
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* @{ |
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*/ |
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Pair> |
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struct select1st |
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: public std::_Select1st<_Pair> {}; |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Pair> |
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struct select2nd |
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: public std::_Select2nd<_Pair> {}; |
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|
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/** @} */ |
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|
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// extension documented next |
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template <class _Arg1, class _Arg2> |
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struct _Project1st : public std::binary_function<_Arg1, _Arg2, _Arg1> |
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{ |
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_Arg1 |
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operator()(const _Arg1& __x, const _Arg2&) const |
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{ return __x; } |
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}; |
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|
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template <class _Arg1, class _Arg2> |
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struct _Project2nd : public std::binary_function<_Arg1, _Arg2, _Arg2> |
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{ |
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_Arg2 |
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operator()(const _Arg1&, const _Arg2& __y) const |
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{ return __y; } |
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}; |
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|
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/** The @c operator() of the @c project1st functor takes two arbitrary |
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* arguments and returns the first one, while @c project2nd returns the |
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* second one. They are extensions provided by SGI. |
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* |
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* @addtogroup SGIextensions |
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* @{ |
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*/ |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Arg1, class _Arg2> |
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struct project1st : public _Project1st<_Arg1, _Arg2> {}; |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Arg1, class _Arg2> |
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struct project2nd : public _Project2nd<_Arg1, _Arg2> {}; |
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/** @} */ |
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|
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// extension documented next |
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template <class _Result> |
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struct _Constant_void_fun |
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{ |
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typedef _Result result_type; |
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result_type _M_val; |
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|
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_Constant_void_fun(const result_type& __v) : _M_val(__v) {} |
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|
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const result_type& |
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operator()() const |
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{ return _M_val; } |
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}; |
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|
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template <class _Result, class _Argument> |
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struct _Constant_unary_fun |
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{ |
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typedef _Argument argument_type; |
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typedef _Result result_type; |
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result_type _M_val; |
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|
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_Constant_unary_fun(const result_type& __v) : _M_val(__v) {} |
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|
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const result_type& |
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operator()(const _Argument&) const |
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{ return _M_val; } |
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}; |
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|
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template <class _Result, class _Arg1, class _Arg2> |
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struct _Constant_binary_fun |
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{ |
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typedef _Arg1 first_argument_type; |
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typedef _Arg2 second_argument_type; |
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typedef _Result result_type; |
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_Result _M_val; |
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|
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_Constant_binary_fun(const _Result& __v) : _M_val(__v) {} |
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|
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const result_type& |
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operator()(const _Arg1&, const _Arg2&) const |
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{ return _M_val; } |
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}; |
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|
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/** These three functors are each constructed from a single arbitrary |
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* variable/value. Later, their @c operator()s completely ignore any |
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* arguments passed, and return the stored value. |
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* - @c constant_void_fun's @c operator() takes no arguments |
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* - @c constant_unary_fun's @c operator() takes one argument (ignored) |
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* - @c constant_binary_fun's @c operator() takes two arguments (ignored) |
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* |
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* The helper creator functions @c constant0, @c constant1, and |
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* @c constant2 each take a @a result argument and construct variables of |
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* the appropriate functor type. |
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* |
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* @addtogroup SGIextensions |
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* @{ |
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*/ |
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Result> |
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struct constant_void_fun |
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: public _Constant_void_fun<_Result> |
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{ |
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constant_void_fun(const _Result& __v) |
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: _Constant_void_fun<_Result>(__v) {} |
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}; |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Result, class _Argument = _Result> |
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struct constant_unary_fun : public _Constant_unary_fun<_Result, _Argument> |
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{ |
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constant_unary_fun(const _Result& __v) |
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: _Constant_unary_fun<_Result, _Argument>(__v) {} |
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}; |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Result, class _Arg1 = _Result, class _Arg2 = _Arg1> |
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struct constant_binary_fun |
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: public _Constant_binary_fun<_Result, _Arg1, _Arg2> |
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{ |
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constant_binary_fun(const _Result& __v) |
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: _Constant_binary_fun<_Result, _Arg1, _Arg2>(__v) {} |
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}; |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Result> |
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inline constant_void_fun<_Result> |
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constant0(const _Result& __val) |
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{ return constant_void_fun<_Result>(__val); } |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Result> |
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inline constant_unary_fun<_Result, _Result> |
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constant1(const _Result& __val) |
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{ return constant_unary_fun<_Result, _Result>(__val); } |
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|
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/// An \link SGIextensions SGI extension \endlink. |
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template <class _Result> |
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inline constant_binary_fun<_Result,_Result,_Result> |
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constant2(const _Result& __val) |
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{ return constant_binary_fun<_Result, _Result, _Result>(__val); } |
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/** @} */ |
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|
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/** The @c subtractive_rng class is documented on |
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* <a href="http://www.sgi.com/tech/stl/">SGI's site</a>. |
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* Note that this code assumes that @c int is 32 bits. |
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* |
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* @ingroup SGIextensions |
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*/ |
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class subtractive_rng |
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: public std::unary_function<unsigned int, unsigned int> |
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{ |
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private: |
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unsigned int _M_table[55]; |
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std::size_t _M_index1; |
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std::size_t _M_index2; |
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|
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public: |
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/// Returns a number less than the argument. |
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unsigned int |
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operator()(unsigned int __limit) |
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{ |
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_M_index1 = (_M_index1 + 1) % 55; |
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_M_index2 = (_M_index2 + 1) % 55; |
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_M_table[_M_index1] = _M_table[_M_index1] - _M_table[_M_index2]; |
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return _M_table[_M_index1] % __limit; |
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} |
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|
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void |
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_M_initialize(unsigned int __seed) |
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{ |
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unsigned int __k = 1; |
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_M_table[54] = __seed; |
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std::size_t __i; |
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for (__i = 0; __i < 54; __i++) |
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{ |
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std::size_t __ii = (21 * (__i + 1) % 55) - 1; |
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_M_table[__ii] = __k; |
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__k = __seed - __k; |
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__seed = _M_table[__ii]; |
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} |
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for (int __loop = 0; __loop < 4; __loop++) |
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{ |
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for (__i = 0; __i < 55; __i++) |
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_M_table[__i] = _M_table[__i] - _M_table[(1 + __i + 30) % 55]; |
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} |
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_M_index1 = 0; |
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_M_index2 = 31; |
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} |
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|
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/// Ctor allowing you to initialize the seed. |
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subtractive_rng(unsigned int __seed) |
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{ _M_initialize(__seed); } |
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|
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/// Default ctor; initializes its state with some number you don't see. |
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subtractive_rng() |
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{ _M_initialize(161803398u); } |
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}; |
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|
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// Mem_fun adaptor helper functions mem_fun1 and mem_fun1_ref, |
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// provided for backward compatibility, they are no longer part of |
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// the C++ standard. |
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|
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template <class _Ret, class _Tp, class _Arg> |
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inline std::mem_fun1_t<_Ret, _Tp, _Arg> |
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mem_fun1(_Ret (_Tp::*__f)(_Arg)) |
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{ return std::mem_fun1_t<_Ret, _Tp, _Arg>(__f); } |
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|
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template <class _Ret, class _Tp, class _Arg> |
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inline std::const_mem_fun1_t<_Ret, _Tp, _Arg> |
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mem_fun1(_Ret (_Tp::*__f)(_Arg) const) |
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{ return std::const_mem_fun1_t<_Ret, _Tp, _Arg>(__f); } |
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|
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template <class _Ret, class _Tp, class _Arg> |
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inline std::mem_fun1_ref_t<_Ret, _Tp, _Arg> |
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mem_fun1_ref(_Ret (_Tp::*__f)(_Arg)) |
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{ return std::mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); } |
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|
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template <class _Ret, class _Tp, class _Arg> |
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inline std::const_mem_fun1_ref_t<_Ret, _Tp, _Arg> |
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mem_fun1_ref(_Ret (_Tp::*__f)(_Arg) const) |
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{ return std::const_mem_fun1_ref_t<_Ret, _Tp, _Arg>(__f); } |
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|
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_GLIBCXX_END_NAMESPACE_VERSION |
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} // namespace |
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|
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#endif |
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|
