libstdc++-v3/include/bits/stl_numeric.h

// Numeric functions implementation -*- C++ -*-

// Copyright (C) 2001 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 2, or (at your option)
// any later version.

// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License along
// with this library; see the file COPYING.  If not, write to the Free
// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
// USA.

// As a special exception, you may use this file as part of a free software
// library without restriction.  Specifically, if other files instantiate
// templates or use macros or inline functions from this file, or you compile
// this file and link it with other files to produce an executable, this
// file does not by itself cause the resulting executable to be covered by
// the GNU General Public License.  This exception does not however
// invalidate any other reasons why the executable file might be covered by
// the GNU General Public License.

/*
 *
 * Copyright (c) 1994
 * Hewlett-Packard Company
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Hewlett-Packard Company makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 *
 * Copyright (c) 1996,1997
 * Silicon Graphics Computer Systems, Inc.
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation.  Silicon Graphics makes no
 * representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 */

/** @file stl_numeric.h
 *  This is an internal header file, included by other library headers.
 *  You should not attempt to use it directly.
 */

#ifndef _CPP_BITS_STL_NUMERIC_H
#define _CPP_BITS_STL_NUMERIC_H 1

namespace std
{

  template<typename _InputIterator, typename _Tp>
    _Tp
    accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
    {
      // concept requirements
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>)

      for ( ; __first != __last; ++__first)
	__init = __init + *__first;
      return __init;
    }

  template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
    _Tp
    accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
	       _BinaryOperation __binary_op)
    {
      // concept requirements
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>)

      for ( ; __first != __last; ++__first)
	__init = __binary_op(__init, *__first);
      return __init;
    }

  template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
    _Tp
    inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
		  _InputIterator2 __first2, _Tp __init)
    {
      // concept requirements
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator2>)

      for ( ; __first1 != __last1; ++__first1, ++__first2)
	__init = __init + (*__first1 * *__first2);
      return __init;
    }

  template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
	    typename _BinaryOperation1, typename _BinaryOperation2>
    _Tp
    inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
		  _InputIterator2 __first2, _Tp __init, 
		  _BinaryOperation1 __binary_op1,
		  _BinaryOperation2 __binary_op2)
    {
      // concept requirements
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator1>)
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator2>)

      for ( ; __first1 != __last1; ++__first1, ++__first2)
	__init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
      return __init;
    }

  template<typename _InputIterator, typename _OutputIterator>
    _OutputIterator 
    partial_sum(_InputIterator __first, _InputIterator __last,
		_OutputIterator __result)
    {
      typedef typename iterator_traits<_InputIterator>::value_type _ValueType;

      // concept requirements
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcpp_function_requires(_OutputIteratorConcept<_OutputIterator, _ValueType>)

      if (__first == __last) return __result;
      *__result = *__first;
      _ValueType __value = *__first;
      while (++__first != __last) {
	__value = __value + *__first;
	*++__result = __value;
      }
      return ++__result;
    }

  template<typename _InputIterator, typename _OutputIterator, typename _BinaryOperation>
    _OutputIterator 
    partial_sum(_InputIterator __first, _InputIterator __last,
		_OutputIterator __result, _BinaryOperation __binary_op)
    {
      typedef typename iterator_traits<_InputIterator>::value_type _ValueType;

      // concept requirements
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcpp_function_requires(_OutputIteratorConcept<_OutputIterator, _ValueType>)

      if (__first == __last) return __result;
      *__result = *__first;
      _ValueType __value = *__first;
      while (++__first != __last) {
	__value = __binary_op(__value, *__first);
	*++__result = __value;
      }
      return ++__result;
    }

  template<typename _InputIterator, typename _OutputIterator>
    _OutputIterator
    adjacent_difference(_InputIterator __first,
			_InputIterator __last, _OutputIterator __result)
    {
      typedef typename iterator_traits<_InputIterator>::value_type _ValueType;

      // concept requirements
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcpp_function_requires(_OutputIteratorConcept<_OutputIterator, _ValueType>)

      if (__first == __last) return __result;
      *__result = *__first;
      _ValueType __value = *__first;
      while (++__first != __last) {
	_ValueType __tmp = *__first;
	*++__result = __tmp - __value;
	__value = __tmp;
      }
      return ++__result;
    }

  template<typename _InputIterator, typename _OutputIterator, typename _BinaryOperation>
    _OutputIterator 
    adjacent_difference(_InputIterator __first, _InputIterator __last,
			_OutputIterator __result, _BinaryOperation __binary_op)
    {
      typedef typename iterator_traits<_InputIterator>::value_type _ValueType;

      // concept requirements
      __glibcpp_function_requires(_InputIteratorConcept<_InputIterator>)
      __glibcpp_function_requires(_OutputIteratorConcept<_OutputIterator, _ValueType>)

      if (__first == __last) return __result;
      *__result = *__first;
      _ValueType __value = *__first;
      while (++__first != __last) {
	_ValueType __tmp = *__first;
	*++__result = __binary_op(__tmp, __value);
	__value = __tmp;
      }
      return ++__result;
    }

  // Returns __x ** __n, where __n >= 0.  _Note that "multiplication"
  // is required to be associative, but not necessarily commutative.

   
  template<typename _Tp, typename _Integer, typename _MonoidOperation>
    _Tp
    __power(_Tp __x, _Integer __n, _MonoidOperation __monoid_op)
    {
      if (__n == 0)
	return identity_element(__monoid_op);
      else {
	while ((__n & 1) == 0) {
	  __n >>= 1;
	  __x = __monoid_op(__x, __x);
	}

	_Tp __result = __x;
	__n >>= 1;
	while (__n != 0) {
	  __x = __monoid_op(__x, __x);
	  if ((__n & 1) != 0)
	    __result = __monoid_op(__result, __x);
	  __n >>= 1;
	}
	return __result;
      }
    }

  template<typename _Tp, typename _Integer>
    inline _Tp
    __power(_Tp __x, _Integer __n)
    { return __power(__x, __n, multiplies<_Tp>()); }

  // Alias for the internal name __power.  Note that power is an extension,
  // not part of the C++ standard.

  template<typename _Tp, typename _Integer, typename _MonoidOperation>
    inline _Tp
    power(_Tp __x, _Integer __n, _MonoidOperation __monoid_op)
    { return __power(__x, __n, __monoid_op); }

  template<typename _Tp, typename _Integer>
    inline _Tp
    power(_Tp __x, _Integer __n)
    { return __power(__x, __n); }

  // iota is not part of the C++ standard.  It is an extension.

  template<typename _ForwardIter, typename _Tp>
    void 
    iota(_ForwardIter __first, _ForwardIter __last, _Tp __value)
    {
      // concept requirements
      __glibcpp_function_requires(_Mutable_ForwardIteratorConcept<_ForwardIter>)
      __glibcpp_function_requires(_ConvertibleConcept<_Tp,
	    typename iterator_traits<_ForwardIter>::value_type>)

      while (__first != __last)
	*__first++ = __value++;
    }

} // namespace std

#endif /* _CPP_BITS_STL_NUMERIC_H */

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