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

// Copyright (C) 2001, 2004 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,

// 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 _STL_NUMERIC_H

#define _STL_NUMERIC_H 1

#include <debug/debug.h>

namespace std

{

  /**

   *  @brief  Accumulate values in a range.

   *

   *  Accumulates the values in the range [first,last) using operator+().  The

   *  initial value is @a init.  The values are processed in order.

   *

   *  @param  first  Start of range.

   *  @param  last  End of range.

   *  @param  init  Starting value to add other values to.

   *  @return  The final sum.

   */

  template<typename _InputIterator, typename _Tp>

    _Tp

    accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)

    {

      // concept requirements

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)

      __glibcxx_requires_valid_range(__first, __last);

      for (; __first != __last; ++__first)

        __init = __init + *__first;

      return __init;

    }

  /**

   *  @brief  Accumulate values in a range with operation.

   *

   *  Accumulates the values in the range [first,last) using the function

   *  object @a binary_op.  The initial value is @a init.  The values are

   *  processed in order.

   *

   *  @param  first  Start of range.

   *  @param  last  End of range.

   *  @param  init  Starting value to add other values to.

   *  @param  binary_op  Function object to accumulate with.

   *  @return  The final sum.

   */

  template<typename _InputIterator, typename _Tp, typename _BinaryOperation>

    _Tp

    accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,

               _BinaryOperation __binary_op)

    {

      // concept requirements

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)

      __glibcxx_requires_valid_range(__first, __last);

      for (; __first != __last; ++__first)

        __init = __binary_op(__init, *__first);

      return __init;

    }

  /**

   *  @brief  Compute inner product of two ranges.

   *

   *  Starting with an initial value of @a init, multiplies successive

   *  elements from the two ranges and adds each product into the accumulated

   *  value using operator+().  The values in the ranges are processed in

   *  order.

   *

   *  @param  first1  Start of range 1.

   *  @param  last1  End of range 1.

   *  @param  first2  Start of range 2.

   *  @param  init  Starting value to add other values to.

   *  @return  The final inner product.

   */

  template<typename _InputIterator1, typename _InputIterator2, typename _Tp>

    _Tp

    inner_product(_InputIterator1 __first1, _InputIterator1 __last1,

                  _InputIterator2 __first2, _Tp __init)

    {

      // concept requirements

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)

      __glibcxx_requires_valid_range(__first1, __last1);

      for (; __first1 != __last1; ++__first1, ++__first2)

        __init = __init + (*__first1 * *__first2);

      return __init;

    }

  /**

   *  @brief  Compute inner product of two ranges.

   *

   *  Starting with an initial value of @a init, applies @a binary_op2 to

   *  successive elements from the two ranges and accumulates each result into

   *  the accumulated value using @a binary_op1.  The values in the ranges are

   *  processed in order.

   *

   *  @param  first1  Start of range 1.

   *  @param  last1  End of range 1.

   *  @param  first2  Start of range 2.

   *  @param  init  Starting value to add other values to.

   *  @param  binary_op1  Function object to accumulate with.

   *  @param  binary_op2  Function object to apply to pairs of input values.

   *  @return  The final inner product.

   */

  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

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)

      __glibcxx_requires_valid_range(__first1, __last1);

      for (; __first1 != __last1; ++__first1, ++__first2)

        __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));

      return __init;

    }

  /**

   *  @brief  Return list of partial sums

   *

   *  Accumulates the values in the range [first,last) using operator+().

   *  As each successive input value is added into the total, that partial sum

   *  is written to @a result.  Therefore, the first value in result is the

   *  first value of the input, the second value in result is the sum of the

   *  first and second input values, and so on.

   *

   *  @param  first  Start of input range.

   *  @param  last  End of input range.

   *  @param  result  Output to write sums to.

   *  @return  Iterator pointing just beyond the values written to result.

   */

  template<typename _InputIterator, typename _OutputIterator>

    _OutputIterator

    partial_sum(_InputIterator __first, _InputIterator __last,

                _OutputIterator __result)

    {

      typedef typename iterator_traits<_InputIterator>::value_type _ValueType;

      // concept requirements

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)

      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,

                                                         _ValueType>)

      __glibcxx_requires_valid_range(__first, __last);

      if (__first == __last)

        return __result;

      _ValueType __value = *__first;

      *__result = __value;

      while (++__first != __last)

        {

          __value = __value + *__first;

          *++__result = __value;

        }

      return ++__result;

    }

  /**

   *  @brief  Return list of partial sums

   *

   *  Accumulates the values in the range [first,last) using operator+().

   *  As each successive input value is added into the total, that partial sum

   *  is written to @a result.  Therefore, the first value in result is the

   *  first value of the input, the second value in result is the sum of the

   *  first and second input values, and so on.

   *

   *  @param  first  Start of input range.

   *  @param  last  End of input range.

   *  @param  result  Output to write sums to.

   *  @return  Iterator pointing just beyond the values written to 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

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)

      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,

                                                         _ValueType>)

      __glibcxx_requires_valid_range(__first, __last);

      if (__first == __last)

        return __result;

      _ValueType __value = *__first;

      *__result = __value;

      while (++__first != __last)

        {

          __value = __binary_op(__value, *__first);

          *++__result = __value;

        }

      return ++__result;

    }

  /**

   *  @brief  Return differences between adjacent values.

   *

   *  Computes the difference between adjacent values in the range

   *  [first,last) using operator-() and writes the result to @a result.

   *

   *  @param  first  Start of input range.

   *  @param  last  End of input range.

   *  @param  result  Output to write sums to.

   *  @return  Iterator pointing just beyond the values written to 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

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)

      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,

                                                         _ValueType>)

      __glibcxx_requires_valid_range(__first, __last);

      if (__first == __last)

        return __result;

      _ValueType __value = *__first;

      *__result = __value;

      while (++__first != __last)

        {

          _ValueType __tmp = *__first;

          *++__result = __tmp - __value;

          __value = __tmp;

        }

      return ++__result;

    }

  /**

   *  @brief  Return differences between adjacent values.

   *

   *  Computes the difference between adjacent values in the range

   *  [first,last) using the function object @a binary_op and writes the

   *  result to @a result.

   *

   *  @param  first  Start of input range.

   *  @param  last  End of input range.

   *  @param  result  Output to write sums to.

   *  @return  Iterator pointing just beyond the values written to 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

      __glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)

      __glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,

                                                         _ValueType>)

      __glibcxx_requires_valid_range(__first, __last);

      if (__first == __last)

        return __result;

      _ValueType __value = *__first;

      *__result = __value;

      while (++__first != __last)

        {

          _ValueType __tmp = *__first;

          *++__result = __binary_op(__tmp, __value);

          __value = __tmp;

        }

      return ++__result;

    }

} // namespace std

#endif /* _STL_NUMERIC_H */