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      1 // Numeric extensions -*- C++ -*-
      2 
      3 // Copyright (C) 2002-2024 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/numeric
     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_NUMERIC
     57 #define _EXT_NUMERIC 1
     58 
     59 #pragma GCC system_header
     60 
     61 #include <bits/requires_hosted.h> // GNU extensions are currently omitted
     62 
     63 #include <bits/concept_check.h>
     64 #include <numeric>
     65 
     66 #include <ext/functional> // For identity_element
     67 
     68 namespace __gnu_cxx _GLIBCXX_VISIBILITY(default)
     69 {
     70 _GLIBCXX_BEGIN_NAMESPACE_VERSION
     71 
     72   // Returns __x ** __n, where __n >= 0.  _Note that "multiplication"
     73   // is required to be associative, but not necessarily commutative.
     74   template<typename _Tp, typename _Integer, typename _MonoidOperation>
     75     _Tp
     76     __power(_Tp __x, _Integer __n, _MonoidOperation __monoid_op)
     77     {
     78       if (__n == 0)
     79 	return identity_element(__monoid_op);
     80       else
     81 	{
     82 	  while ((__n & 1) == 0)
     83 	    {
     84 	      __n >>= 1;
     85 	      __x = __monoid_op(__x, __x);
     86 	    }
     87 
     88 	  _Tp __result = __x;
     89 	  __n >>= 1;
     90 	  while (__n != 0)
     91 	    {
     92 	      __x = __monoid_op(__x, __x);
     93 	      if ((__n & 1) != 0)
     94 		__result = __monoid_op(__result, __x);
     95 	      __n >>= 1;
     96 	    }
     97 	  return __result;
     98 	}
     99     }
    100 
    101   template<typename _Tp, typename _Integer>
    102     inline _Tp
    103     __power(_Tp __x, _Integer __n)
    104     { return __power(__x, __n, std::multiplies<_Tp>()); }
    105 
    106   /**
    107    *  This is an SGI extension.
    108    *  @ingroup SGIextensions
    109    *  @doctodo
    110   */
    111   // Alias for the internal name __power.  Note that power is an extension,
    112   // not part of the C++ standard.
    113   template<typename _Tp, typename _Integer, typename _MonoidOperation>
    114     inline _Tp
    115     power(_Tp __x, _Integer __n, _MonoidOperation __monoid_op)
    116     { return __power(__x, __n, __monoid_op); }
    117 
    118   /**
    119    *  This is an SGI extension.
    120    *  @ingroup SGIextensions
    121    *  @doctodo
    122   */
    123   template<typename _Tp, typename _Integer>
    124     inline _Tp
    125     power(_Tp __x, _Integer __n)
    126     { return __power(__x, __n); }
    127 
    128 #if __cplusplus >= 201103L
    129   using std::iota;
    130 #else
    131   /**
    132    *  This is an SGI extension.
    133    *  @ingroup SGIextensions
    134    *  @doctodo
    135   */
    136   // iota is not part of the standard until C++11.  It is an extension.
    137   template<typename _ForwardIter, typename _Tp>
    138     void
    139     iota(_ForwardIter __first, _ForwardIter __last, _Tp __value)
    140     {
    141       // concept requirements
    142       __glibcxx_function_requires(_Mutable_ForwardIteratorConcept<_ForwardIter>)
    143       __glibcxx_function_requires(_ConvertibleConcept<_Tp,
    144 	    typename std::iterator_traits<_ForwardIter>::value_type>)
    145 
    146       while (__first != __last)
    147 	*__first++ = __value++;
    148     }
    149 #endif  // C++11
    150 
    151 _GLIBCXX_END_NAMESPACE_VERSION
    152 } // namespace
    153 
    154 #endif
    155