libstdc++-v3/include/ext/numeric

   1 // Numeric extensions -*- C++ -*-
   2
   3 // Copyright (C) 2002 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 2, 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 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 /*
  31  *
  32  * Copyright (c) 1994
  33  * Hewlett-Packard Company
  34  *
  35  * Permission to use, copy, modify, distribute and sell this software
  36  * and its documentation for any purpose is hereby granted without fee,
  37  * provided that the above copyright notice appear in all copies and
  38  * that both that copyright notice and this permission notice appear
  39  * in supporting documentation.  Hewlett-Packard Company makes no
  40  * representations about the suitability of this software for any
  41  * purpose.  It is provided "as is" without express or implied warranty.
  42  *
  43  *
  44  * Copyright (c) 1996
  45  * Silicon Graphics Computer Systems, Inc.
  46  *
  47  * Permission to use, copy, modify, distribute and sell this software
  48  * and its documentation for any purpose is hereby granted without fee,
  49  * provided that the above copyright notice appear in all copies and
  50  * that both that copyright notice and this permission notice appear
  51  * in supporting documentation.  Silicon Graphics makes no
  52  * representations about the suitability of this software for any
  53  * purpose.  It is provided "as is" without express or implied warranty.
  54  */
  55
  56 /** @file ext/numeric
  57  *  This file is a GNU extension to the Standard C++ Library (possibly
  58  *  containing extensions from the HP/SGI STL subset).  You should only
  59  *  include this header if you are using GCC 3 or later.
  60  */
  61
  62 #ifndef _EXT_NUMERIC
  63 #define _EXT_NUMERIC
  64
  65 #pragma GCC system_header
  66 #include <bits/concept_check.h>
  67 #include <numeric>
  68
  69 #include <ext/functional> // For identity_element
  70
  71 namespace __gnu_cxx
  72 {
  73   // Returns __x ** __n, where __n >= 0.  _Note that "multiplication"
  74   // is required to be associative, but not necessarily commutative.
  75
  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         while ((__n & 1) == 0) {
  84           __n >>= 1;
  85           __x = __monoid_op(__x, __x);
  86         }
  87
  88         _Tp __result = __x;
  89         __n >>= 1;
  90         while (__n != 0) {
  91           __x = __monoid_op(__x, __x);
  92           if ((__n & 1) != 0)
  93             __result = __monoid_op(__result, __x);
  94           __n >>= 1;
  95         }
  96         return __result;
  97       }
  98     }
  99
 100   template<typename _Tp, typename _Integer>
 101     inline _Tp
 102     __power(_Tp __x, _Integer __n)
 103     { return __power(__x, __n, std::multiplies<_Tp>()); }
 104
 105   // Alias for the internal name __power.  Note that power is an extension,
 106   // not part of the C++ standard.
 107
 108   /**
 109    *  This is an SGI extension.
 110    *  @ingroup SGIextensions
 111    *  @doctodo
 112   */
 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   // iota is not part of the C++ standard.  It is an extension.
 129
 130   /**
 131    *  This is an SGI extension.
 132    *  @ingroup SGIextensions
 133    *  @doctodo
 134   */
 135   template<typename _ForwardIter, typename _Tp>
 136     void
 137     iota(_ForwardIter __first, _ForwardIter __last, _Tp __value)
 138     {
 139       // concept requirements
 140       __glibcpp_function_requires(_Mutable_ForwardIteratorConcept<_ForwardIter>)
 141       __glibcpp_function_requires(_ConvertibleConcept<_Tp,
 142             typename std::iterator_traits<_ForwardIter>::value_type>)
 143
 144       while (__first != __last)
 145         *__first++ = __value++;
 146     }
 147
 148 } // namespace __gnu_cxx
 149
 150 #endif /* _EXT_NUMERIC */
 151