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// Heap implementation -*- C++ -*-
// Copyright (C) 2001, 2004, 2005, 2006 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) 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_heap.h
* This is an internal header file, included by other library headers.
* You should not attempt to use it directly.
*/
#ifndef _STL_HEAP_H
#define _STL_HEAP_H 1
#include <debug/debug.h>
_GLIBCXX_BEGIN_NAMESPACE(std)
// is_heap, a predicate testing whether or not a range is
// a heap. This function is an extension, not part of the C++
// standard.
template<typename _RandomAccessIterator, typename _Distance>
bool
__is_heap(_RandomAccessIterator __first, _Distance __n)
{
_Distance __parent = 0;
for (_Distance __child = 1; __child < __n; ++__child)
{
if (__first[__parent] < __first[__child])
return false;
if ((__child & 1) == 0)
++__parent;
}
return true;
}
template<typename _RandomAccessIterator, typename _Distance,
typename _StrictWeakOrdering>
bool
__is_heap(_RandomAccessIterator __first, _StrictWeakOrdering __comp,
_Distance __n)
{
_Distance __parent = 0;
for (_Distance __child = 1; __child < __n; ++__child)
{
if (__comp(__first[__parent], __first[__child]))
return false;
if ((__child & 1) == 0)
++__parent;
}
return true;
}
template<typename _RandomAccessIterator>
bool
__is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
{ return std::__is_heap(__first, std::distance(__first, __last)); }
template<typename _RandomAccessIterator, typename _StrictWeakOrdering>
bool
__is_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
_StrictWeakOrdering __comp)
{ return std::__is_heap(__first, __comp, std::distance(__first, __last)); }
// Heap-manipulation functions: push_heap, pop_heap, make_heap, sort_heap.
template<typename _RandomAccessIterator, typename _Distance, typename _Tp>
void
__push_heap(_RandomAccessIterator __first,
_Distance __holeIndex, _Distance __topIndex, _Tp __value)
{
_Distance __parent = (__holeIndex - 1) / 2;
while (__holeIndex > __topIndex && *(__first + __parent) < __value)
{
*(__first + __holeIndex) = *(__first + __parent);
__holeIndex = __parent;
__parent = (__holeIndex - 1) / 2;
}
*(__first + __holeIndex) = __value;
}
/**
* @brief Push an element onto a heap.
* @param first Start of heap.
* @param last End of heap + element.
* @ingroup heap
*
* This operation pushes the element at last-1 onto the valid heap over the
* range [first,last-1). After completion, [first,last) is a valid heap.
*/
template<typename _RandomAccessIterator>
inline void
push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
{
typedef typename iterator_traits<_RandomAccessIterator>::value_type
_ValueType;
typedef typename iterator_traits<_RandomAccessIterator>::difference_type
_DistanceType;
// concept requirements
__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
_RandomAccessIterator>)
__glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
__glibcxx_requires_valid_range(__first, __last);
// __glibcxx_requires_heap(__first, __last - 1);
std::__push_heap(__first, _DistanceType((__last - __first) - 1),
_DistanceType(0), _ValueType(*(__last - 1)));
}
template<typename _RandomAccessIterator, typename _Distance, typename _Tp,
typename _Compare>
void
__push_heap(_RandomAccessIterator __first, _Distance __holeIndex,
_Distance __topIndex, _Tp __value, _Compare __comp)
{
_Distance __parent = (__holeIndex - 1) / 2;
while (__holeIndex > __topIndex
&& __comp(*(__first + __parent), __value))
{
*(__first + __holeIndex) = *(__first + __parent);
__holeIndex = __parent;
__parent = (__holeIndex - 1) / 2;
}
*(__first + __holeIndex) = __value;
}
/**
* @brief Push an element onto a heap using comparison functor.
* @param first Start of heap.
* @param last End of heap + element.
* @param comp Comparison functor.
* @ingroup heap
*
* This operation pushes the element at last-1 onto the valid heap over the
* range [first,last-1). After completion, [first,last) is a valid heap.
* Compare operations are performed using comp.
*/
template<typename _RandomAccessIterator, typename _Compare>
inline void
push_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
_Compare __comp)
{
typedef typename iterator_traits<_RandomAccessIterator>::value_type
_ValueType;
typedef typename iterator_traits<_RandomAccessIterator>::difference_type
_DistanceType;
// concept requirements
__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
_RandomAccessIterator>)
__glibcxx_requires_valid_range(__first, __last);
__glibcxx_requires_heap_pred(__first, __last - 1, __comp);
std::__push_heap(__first, _DistanceType((__last - __first) - 1),
_DistanceType(0), _ValueType(*(__last - 1)), __comp);
}
template<typename _RandomAccessIterator, typename _Distance, typename _Tp>
void
__adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex,
_Distance __len, _Tp __value)
{
const _Distance __topIndex = __holeIndex;
_Distance __secondChild = 2 * __holeIndex + 2;
while (__secondChild < __len)
{
if (*(__first + __secondChild) < *(__first + (__secondChild - 1)))
__secondChild--;
*(__first + __holeIndex) = *(__first + __secondChild);
__holeIndex = __secondChild;
__secondChild = 2 * (__secondChild + 1);
}
if (__secondChild == __len)
{
*(__first + __holeIndex) = *(__first + (__secondChild - 1));
__holeIndex = __secondChild - 1;
}
std::__push_heap(__first, __holeIndex, __topIndex, __value);
}
template<typename _RandomAccessIterator, typename _Tp>
inline void
__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
_RandomAccessIterator __result, _Tp __value)
{
typedef typename iterator_traits<_RandomAccessIterator>::difference_type
_Distance;
*__result = *__first;
std::__adjust_heap(__first, _Distance(0), _Distance(__last - __first),
__value);
}
/**
* @brief Pop an element off a heap.
* @param first Start of heap.
* @param last End of heap.
* @ingroup heap
*
* This operation pops the top of the heap. The elements first and last-1
* are swapped and [first,last-1) is made into a heap.
*/
template<typename _RandomAccessIterator>
inline void
pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
{
typedef typename iterator_traits<_RandomAccessIterator>::value_type
_ValueType;
// concept requirements
__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
_RandomAccessIterator>)
__glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
__glibcxx_requires_valid_range(__first, __last);
__glibcxx_requires_heap(__first, __last);
std::__pop_heap(__first, __last - 1, __last - 1,
_ValueType(*(__last - 1)));
}
template<typename _RandomAccessIterator, typename _Distance,
typename _Tp, typename _Compare>
void
__adjust_heap(_RandomAccessIterator __first, _Distance __holeIndex,
_Distance __len, _Tp __value, _Compare __comp)
{
const _Distance __topIndex = __holeIndex;
_Distance __secondChild = 2 * __holeIndex + 2;
while (__secondChild < __len)
{
if (__comp(*(__first + __secondChild),
*(__first + (__secondChild - 1))))
__secondChild--;
*(__first + __holeIndex) = *(__first + __secondChild);
__holeIndex = __secondChild;
__secondChild = 2 * (__secondChild + 1);
}
if (__secondChild == __len)
{
*(__first + __holeIndex) = *(__first + (__secondChild - 1));
__holeIndex = __secondChild - 1;
}
std::__push_heap(__first, __holeIndex, __topIndex, __value, __comp);
}
template<typename _RandomAccessIterator, typename _Tp, typename _Compare>
inline void
__pop_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
_RandomAccessIterator __result, _Tp __value, _Compare __comp)
{
typedef typename iterator_traits<_RandomAccessIterator>::difference_type
_Distance;
*__result = *__first;
std::__adjust_heap(__first, _Distance(0), _Distance(__last - __first),
__value, __comp);
}
/**
* @brief Pop an element off a heap using comparison functor.
* @param first Start of heap.
* @param last End of heap.
* @param comp Comparison functor to use.
* @ingroup heap
*
* This operation pops the top of the heap. The elements first and last-1
* are swapped and [first,last-1) is made into a heap. Comparisons are
* made using comp.
*/
template<typename _RandomAccessIterator, typename _Compare>
inline void
pop_heap(_RandomAccessIterator __first,
_RandomAccessIterator __last, _Compare __comp)
{
// concept requirements
__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
_RandomAccessIterator>)
__glibcxx_requires_valid_range(__first, __last);
__glibcxx_requires_heap_pred(__first, __last, __comp);
typedef typename iterator_traits<_RandomAccessIterator>::value_type
_ValueType;
std::__pop_heap(__first, __last - 1, __last - 1,
_ValueType(*(__last - 1)), __comp);
}
/**
* @brief Construct a heap over a range.
* @param first Start of heap.
* @param last End of heap.
* @ingroup heap
*
* This operation makes the elements in [first,last) into a heap.
*/
template<typename _RandomAccessIterator>
void
make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
{
typedef typename iterator_traits<_RandomAccessIterator>::value_type
_ValueType;
typedef typename iterator_traits<_RandomAccessIterator>::difference_type
_DistanceType;
// concept requirements
__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
_RandomAccessIterator>)
__glibcxx_function_requires(_LessThanComparableConcept<_ValueType>)
__glibcxx_requires_valid_range(__first, __last);
if (__last - __first < 2)
return;
const _DistanceType __len = __last - __first;
_DistanceType __parent = (__len - 2) / 2;
while (true)
{
std::__adjust_heap(__first, __parent, __len,
_ValueType(*(__first + __parent)));
if (__parent == 0)
return;
__parent--;
}
}
/**
* @brief Construct a heap over a range using comparison functor.
* @param first Start of heap.
* @param last End of heap.
* @param comp Comparison functor to use.
* @ingroup heap
*
* This operation makes the elements in [first,last) into a heap.
* Comparisons are made using comp.
*/
template<typename _RandomAccessIterator, typename _Compare>
inline void
make_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
_Compare __comp)
{
typedef typename iterator_traits<_RandomAccessIterator>::value_type
_ValueType;
typedef typename iterator_traits<_RandomAccessIterator>::difference_type
_DistanceType;
// concept requirements
__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
_RandomAccessIterator>)
__glibcxx_requires_valid_range(__first, __last);
if (__last - __first < 2)
return;
const _DistanceType __len = __last - __first;
_DistanceType __parent = (__len - 2) / 2;
while (true)
{
std::__adjust_heap(__first, __parent, __len,
_ValueType(*(__first + __parent)), __comp);
if (__parent == 0)
return;
__parent--;
}
}
/**
* @brief Sort a heap.
* @param first Start of heap.
* @param last End of heap.
* @ingroup heap
*
* This operation sorts the valid heap in the range [first,last).
*/
template<typename _RandomAccessIterator>
void
sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last)
{
// concept requirements
__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
_RandomAccessIterator>)
__glibcxx_function_requires(_LessThanComparableConcept<
typename iterator_traits<_RandomAccessIterator>::value_type>)
__glibcxx_requires_valid_range(__first, __last);
// __glibcxx_requires_heap(__first, __last);
while (__last - __first > 1)
std::pop_heap(__first, _RandomAccessIterator(__last--));
}
/**
* @brief Sort a heap using comparison functor.
* @param first Start of heap.
* @param last End of heap.
* @param comp Comparison functor to use.
* @ingroup heap
*
* This operation sorts the valid heap in the range [first,last).
* Comparisons are made using comp.
*/
template<typename _RandomAccessIterator, typename _Compare>
void
sort_heap(_RandomAccessIterator __first, _RandomAccessIterator __last,
_Compare __comp)
{
// concept requirements
__glibcxx_function_requires(_Mutable_RandomAccessIteratorConcept<
_RandomAccessIterator>)
__glibcxx_requires_valid_range(__first, __last);
__glibcxx_requires_heap_pred(__first, __last, __comp);
while (__last - __first > 1)
std::pop_heap(__first, _RandomAccessIterator(__last--), __comp);
}
_GLIBCXX_END_NAMESPACE
#endif /* _STL_HEAP_H */
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