libstdc++-v3/include/ext/numeric

   1 // Numeric extensions -*- C++ -*-
   2
   3 // Copyright (C) 2002-2022 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