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