cb1d5dbaeb
2004-11-03 Jonathan Wakely <redi@gcc.gnu.org> * include/bits/stl_numeric.h (partial_sum, adjacent_difference): Avoid dereferencing two times __first in the prologue. From-SVN: r90038
341 lines
12 KiB
C++
341 lines
12 KiB
C++
// Numeric functions implementation -*- C++ -*-
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// Copyright (C) 2001, 2004 Free Software Foundation, Inc.
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//
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// This file is part of the GNU ISO C++ Library. This library is free
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// software; you can redistribute it and/or modify it under the
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// terms of the GNU General Public License as published by the
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// Free Software Foundation; either version 2, or (at your option)
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// any later version.
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// This library is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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// You should have received a copy of the GNU General Public License along
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// with this library; see the file COPYING. If not, write to the Free
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// Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
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// USA.
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// As a special exception, you may use this file as part of a free software
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// library without restriction. Specifically, if other files instantiate
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// templates or use macros or inline functions from this file, or you compile
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// this file and link it with other files to produce an executable, this
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// file does not by itself cause the resulting executable to be covered by
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// the GNU General Public License. This exception does not however
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// invalidate any other reasons why the executable file might be covered by
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// the GNU General Public License.
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/*
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*
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* Copyright (c) 1994
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* Hewlett-Packard Company
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Hewlett-Packard Company makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*
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*
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* Copyright (c) 1996,1997
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* Silicon Graphics Computer Systems, Inc.
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*
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* Permission to use, copy, modify, distribute and sell this software
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* and its documentation for any purpose is hereby granted without fee,
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* provided that the above copyright notice appear in all copies and
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* that both that copyright notice and this permission notice appear
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* in supporting documentation. Silicon Graphics makes no
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* representations about the suitability of this software for any
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* purpose. It is provided "as is" without express or implied warranty.
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*/
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/** @file stl_numeric.h
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* This is an internal header file, included by other library headers.
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* You should not attempt to use it directly.
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*/
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#ifndef _STL_NUMERIC_H
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#define _STL_NUMERIC_H 1
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#include <debug/debug.h>
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namespace std
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{
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/**
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* @brief Accumulate values in a range.
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*
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* Accumulates the values in the range [first,last) using operator+(). The
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* initial value is @a init. The values are processed in order.
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*
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* @param first Start of range.
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* @param last End of range.
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* @param init Starting value to add other values to.
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* @return The final sum.
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*/
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template<typename _InputIterator, typename _Tp>
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_Tp
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accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_requires_valid_range(__first, __last);
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for (; __first != __last; ++__first)
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__init = __init + *__first;
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return __init;
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}
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/**
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* @brief Accumulate values in a range with operation.
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*
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* Accumulates the values in the range [first,last) using the function
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* object @a binary_op. The initial value is @a init. The values are
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* processed in order.
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*
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* @param first Start of range.
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* @param last End of range.
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* @param init Starting value to add other values to.
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* @param binary_op Function object to accumulate with.
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* @return The final sum.
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*/
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template<typename _InputIterator, typename _Tp, typename _BinaryOperation>
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_Tp
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accumulate(_InputIterator __first, _InputIterator __last, _Tp __init,
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_BinaryOperation __binary_op)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_requires_valid_range(__first, __last);
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for (; __first != __last; ++__first)
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__init = __binary_op(__init, *__first);
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return __init;
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}
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/**
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* @brief Compute inner product of two ranges.
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*
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* Starting with an initial value of @a init, multiplies successive
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* elements from the two ranges and adds each product into the accumulated
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* value using operator+(). The values in the ranges are processed in
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* order.
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*
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* @param first1 Start of range 1.
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* @param last1 End of range 1.
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* @param first2 Start of range 2.
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* @param init Starting value to add other values to.
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* @return The final inner product.
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*/
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template<typename _InputIterator1, typename _InputIterator2, typename _Tp>
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_Tp
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inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
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_InputIterator2 __first2, _Tp __init)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
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__glibcxx_requires_valid_range(__first1, __last1);
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for (; __first1 != __last1; ++__first1, ++__first2)
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__init = __init + (*__first1 * *__first2);
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return __init;
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}
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/**
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* @brief Compute inner product of two ranges.
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*
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* Starting with an initial value of @a init, applies @a binary_op2 to
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* successive elements from the two ranges and accumulates each result into
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* the accumulated value using @a binary_op1. The values in the ranges are
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* processed in order.
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*
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* @param first1 Start of range 1.
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* @param last1 End of range 1.
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* @param first2 Start of range 2.
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* @param init Starting value to add other values to.
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* @param binary_op1 Function object to accumulate with.
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* @param binary_op2 Function object to apply to pairs of input values.
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* @return The final inner product.
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*/
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template<typename _InputIterator1, typename _InputIterator2, typename _Tp,
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typename _BinaryOperation1, typename _BinaryOperation2>
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_Tp
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inner_product(_InputIterator1 __first1, _InputIterator1 __last1,
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_InputIterator2 __first2, _Tp __init,
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_BinaryOperation1 __binary_op1,
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_BinaryOperation2 __binary_op2)
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{
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator1>)
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator2>)
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__glibcxx_requires_valid_range(__first1, __last1);
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for (; __first1 != __last1; ++__first1, ++__first2)
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__init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
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return __init;
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}
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/**
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* @brief Return list of partial sums
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*
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* Accumulates the values in the range [first,last) using operator+().
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* As each successive input value is added into the total, that partial sum
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* is written to @a result. Therefore, the first value in result is the
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* first value of the input, the second value in result is the sum of the
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* first and second input values, and so on.
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*
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* @param first Start of input range.
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* @param last End of input range.
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* @param result Output to write sums to.
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* @return Iterator pointing just beyond the values written to result.
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*/
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template<typename _InputIterator, typename _OutputIterator>
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_OutputIterator
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partial_sum(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result)
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{
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typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
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_ValueType>)
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__glibcxx_requires_valid_range(__first, __last);
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if (__first == __last)
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return __result;
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_ValueType __value = *__first;
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*__result = __value;
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while (++__first != __last)
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{
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__value = __value + *__first;
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*++__result = __value;
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}
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return ++__result;
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}
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/**
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* @brief Return list of partial sums
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*
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* Accumulates the values in the range [first,last) using operator+().
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* As each successive input value is added into the total, that partial sum
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* is written to @a result. Therefore, the first value in result is the
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* first value of the input, the second value in result is the sum of the
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* first and second input values, and so on.
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*
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* @param first Start of input range.
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* @param last End of input range.
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* @param result Output to write sums to.
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* @return Iterator pointing just beyond the values written to result.
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*/
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template<typename _InputIterator, typename _OutputIterator,
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typename _BinaryOperation>
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_OutputIterator
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partial_sum(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result, _BinaryOperation __binary_op)
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{
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typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
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_ValueType>)
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__glibcxx_requires_valid_range(__first, __last);
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if (__first == __last)
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return __result;
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_ValueType __value = *__first;
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*__result = __value;
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while (++__first != __last)
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{
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__value = __binary_op(__value, *__first);
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*++__result = __value;
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}
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return ++__result;
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}
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/**
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* @brief Return differences between adjacent values.
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*
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* Computes the difference between adjacent values in the range
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* [first,last) using operator-() and writes the result to @a result.
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*
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* @param first Start of input range.
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* @param last End of input range.
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* @param result Output to write sums to.
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* @return Iterator pointing just beyond the values written to result.
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*/
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template<typename _InputIterator, typename _OutputIterator>
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_OutputIterator
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adjacent_difference(_InputIterator __first,
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_InputIterator __last, _OutputIterator __result)
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{
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typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
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_ValueType>)
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__glibcxx_requires_valid_range(__first, __last);
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if (__first == __last)
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return __result;
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_ValueType __value = *__first;
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*__result = __value;
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while (++__first != __last)
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{
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_ValueType __tmp = *__first;
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*++__result = __tmp - __value;
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__value = __tmp;
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}
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return ++__result;
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}
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/**
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* @brief Return differences between adjacent values.
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*
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* Computes the difference between adjacent values in the range
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* [first,last) using the function object @a binary_op and writes the
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* result to @a result.
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*
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* @param first Start of input range.
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* @param last End of input range.
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* @param result Output to write sums to.
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* @return Iterator pointing just beyond the values written to result.
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*/
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template<typename _InputIterator, typename _OutputIterator,
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typename _BinaryOperation>
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_OutputIterator
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adjacent_difference(_InputIterator __first, _InputIterator __last,
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_OutputIterator __result, _BinaryOperation __binary_op)
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{
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typedef typename iterator_traits<_InputIterator>::value_type _ValueType;
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// concept requirements
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__glibcxx_function_requires(_InputIteratorConcept<_InputIterator>)
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__glibcxx_function_requires(_OutputIteratorConcept<_OutputIterator,
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_ValueType>)
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__glibcxx_requires_valid_range(__first, __last);
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if (__first == __last)
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return __result;
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_ValueType __value = *__first;
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*__result = __value;
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while (++__first != __last)
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{
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_ValueType __tmp = *__first;
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*++__result = __binary_op(__tmp, __value);
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__value = __tmp;
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}
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return ++__result;
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}
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} // namespace std
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#endif /* _STL_NUMERIC_H */
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