kernel/util: Add MinMaxHeap implementation
This commit is contained in:
Pawel Dziepak
parent
278c9784a1
commit
18c0d163ed
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/*
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* Copyright 2013 Haiku, Inc. All rights reserved.
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* Distributed under the terms of the MIT License.
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*
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* Authors:
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* Paweł Dziepak, pdziepak@quarnos.org
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*/
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#ifndef KERNEL_UTIL_MIN_MAX_HEAP_H
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#define KERNEL_UTIL_MIN_MAX_HEAP_H
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#include <debug.h>
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#include <SupportDefs.h>
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template<typename Element, typename Key>
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struct MinMaxHeapLink {
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MinMaxHeapLink();
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bool fMinTree;
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int fIndex;
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Key fKey;
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};
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template<typename Element, typename Key>
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class MinMaxHeapLinkImpl {
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private:
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typedef MinMaxHeapLink<Element, Key> Link;
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public:
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inline Link* GetMinMaxHeapLink();
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private:
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Link fMinMaxHeapLink;
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};
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template<typename Element, typename Key>
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class MinMaxHeapStandardGetLink {
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private:
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typedef MinMaxHeapLink<Element, Key> Link;
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public:
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inline Link* operator()(Element* element) const;
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};
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template<typename Element, typename Key,
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MinMaxHeapLink<Element, Key> Element::*LinkMember>
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class MinMaxHeapMemberGetLink {
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private:
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typedef MinMaxHeapLink<Element, Key> Link;
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public:
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inline Link* operator()(Element* element) const;
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};
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template<typename Key>
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class MinMaxHeapCompare {
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public:
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inline bool operator()(Key a, Key b);
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};
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#define MIN_MAX_HEAP_TEMPLATE_LIST \
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template<typename Element, typename Key, typename Compare, typename GetLink>
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#define MIN_MAX_HEAP_CLASS_NAME MinMaxHeap<Element, Key, Compare, GetLink>
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template<typename Element, typename Key,
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typename Compare = MinMaxHeapCompare<Key>,
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typename GetLink = MinMaxHeapStandardGetLink<Element, Key> >
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class MinMaxHeap {
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public:
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MinMaxHeap();
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~MinMaxHeap();
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inline Element* PeekMinimum();
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inline Element* PeekMaximum();
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static const Key& GetKey(Element* element);
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inline void ModifyKey(Element* element, Key newKey);
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inline void RemoveMinimum();
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inline void RemoveMaximum();
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inline status_t Insert(Element* element, Key key);
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private:
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status_t _GrowHeap();
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void _MoveUp(MinMaxHeapLink<Element, Key>* link);
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void _MoveDown(MinMaxHeapLink<Element, Key>* link);
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bool _ChangeTree(MinMaxHeapLink<Element, Key>* link);
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void _RemoveLast(bool minTree);
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Element** fMinElements;
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int fMinLastElement;
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Element** fMaxElements;
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int fMaxLastElement;
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int fSize;
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static Compare sCompare;
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static GetLink sGetLink;
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};
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#if KDEBUG
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template<typename Element, typename Key>
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MinMaxHeapLink<Element, Key>::MinMaxHeapLink()
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:
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fIndex(-1)
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{
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}
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#else
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template<typename Element, typename Key>
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MinMaxHeapLink<Element, Key>::MinMaxHeapLink()
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{
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}
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#endif
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template<typename Element, typename Key>
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MinMaxHeapLink<Element, Key>*
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MinMaxHeapLinkImpl<Element, Key>::GetMinMaxHeapLink()
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{
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return &fMinMaxHeapLink;
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}
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template<typename Element, typename Key>
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MinMaxHeapLink<Element, Key>*
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MinMaxHeapStandardGetLink<Element, Key>::operator()(Element* element) const
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{
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return element->GetMinMaxHeapLink();
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}
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template<typename Element, typename Key,
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MinMaxHeapLink<Element, Key> Element::*LinkMember>
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MinMaxHeapLink<Element, Key>*
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MinMaxHeapMemberGetLink<Element, Key, LinkMember>::operator()(
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Element* element) const
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{
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return &(element->*LinkMember);
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}
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template<typename Key>
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bool
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MinMaxHeapCompare<Key>::operator()(Key a, Key b)
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{
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return a < b;
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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MIN_MAX_HEAP_CLASS_NAME::MinMaxHeap()
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:
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fMinElements(NULL),
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fMinLastElement(0),
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fMaxElements(NULL),
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fMaxLastElement(0),
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fSize(0)
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{
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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MIN_MAX_HEAP_CLASS_NAME::~MinMaxHeap()
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{
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free(fMinElements);
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free(fMaxElements);
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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Element*
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MIN_MAX_HEAP_CLASS_NAME::PeekMinimum()
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{
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if (fMinLastElement > 0)
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return fMinElements[0];
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else if (fMaxLastElement > 0) {
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ASSERT(fMaxLastElement == 1);
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return fMaxElements[0];
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}
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return NULL;
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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Element*
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MIN_MAX_HEAP_CLASS_NAME::PeekMaximum()
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{
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if (fMaxLastElement > 0)
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return fMaxElements[0];
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else if (fMinLastElement > 0) {
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ASSERT(fMinLastElement == 1);
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return fMinElements[0];
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}
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return NULL;
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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const Key&
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MIN_MAX_HEAP_CLASS_NAME::GetKey(Element* element)
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{
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return sGetLink(element)->fKey;
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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void
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MIN_MAX_HEAP_CLASS_NAME::ModifyKey(Element* element, Key newKey)
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{
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MinMaxHeapLink<Element, Key>* link = sGetLink(element);
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Key oldKey = link->fKey;
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link->fKey = newKey;
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if (sCompare(newKey, oldKey) && link->fMinTree)
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_MoveUp(link);
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else
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_MoveDown(link);
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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void
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MIN_MAX_HEAP_CLASS_NAME::RemoveMinimum()
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{
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if (fMinLastElement == 0) {
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ASSERT(fMaxLastElement == 1);
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RemoveMaximum();
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return;
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}
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#if KDEBUG
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Element* element = PeekMinimum();
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MinMaxHeapLink<Element, Key>* link = sGetLink(element);
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link->fIndex = -1;
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#endif
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_RemoveLast(true);
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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void
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MIN_MAX_HEAP_CLASS_NAME::RemoveMaximum()
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{
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if (fMaxLastElement == 0) {
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ASSERT(fMinLastElement == 1);
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RemoveMinimum();
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return;
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}
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#if KDEBUG
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Element* element = PeekMaximum();
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MinMaxHeapLink<Element, Key>* link = sGetLink(element);
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link->fIndex = -1;
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#endif
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_RemoveLast(false);
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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status_t
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MIN_MAX_HEAP_CLASS_NAME::Insert(Element* element, Key key)
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{
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if (min_c(fMinLastElement, fMaxLastElement) == fSize) {
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ASSERT(max_c(fMinLastElement, fMaxLastElement) == fSize);
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status_t result = _GrowHeap();
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if (result != B_OK)
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return result;
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}
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ASSERT(fMinLastElement != fSize || fMaxLastElement != fSize);
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MinMaxHeapLink<Element, Key>* link = sGetLink(element);
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link->fMinTree = fMinLastElement < fMaxLastElement;
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int& lastElement = link->fMinTree ? fMinLastElement : fMaxLastElement;
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Element** tree = link->fMinTree ? fMinElements : fMaxElements;
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tree[lastElement] = element;
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link->fIndex = lastElement++;
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link->fKey = key;
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if (!_ChangeTree(link))
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_MoveUp(link);
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return B_OK;
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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status_t
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MIN_MAX_HEAP_CLASS_NAME::_GrowHeap()
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{
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int newSize = max_c(fSize * 2, 4);
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size_t arraySize = newSize * sizeof(Element*);
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Element** newBuffer
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= reinterpret_cast<Element**>(realloc(fMinElements, arraySize));
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if (newBuffer == NULL)
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return B_NO_MEMORY;
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fMinElements = newBuffer;
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newBuffer
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= reinterpret_cast<Element**>(realloc(fMaxElements, arraySize));
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if (newBuffer == NULL)
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return B_NO_MEMORY;
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fMaxElements = newBuffer;
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fSize = newSize;
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return B_OK;
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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void
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MIN_MAX_HEAP_CLASS_NAME::_MoveUp(MinMaxHeapLink<Element, Key>* link)
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{
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Element** tree = link->fMinTree ? fMinElements : fMaxElements;
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while (true) {
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if (link->fIndex <= 0)
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break;
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int parent = (link->fIndex - 1) / 2;
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bool isSmaller = sCompare(link->fKey, sGetLink(tree[parent])->fKey);
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if (isSmaller ^ !link->fMinTree) {
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ASSERT(sGetLink(tree[parent])->fIndex == parent);
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sGetLink(tree[parent])->fIndex = link->fIndex;
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Element* element = tree[link->fIndex];
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tree[link->fIndex] = tree[parent];
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tree[parent] = element;
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link->fIndex = parent;
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} else
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break;
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}
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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void
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MIN_MAX_HEAP_CLASS_NAME::_MoveDown(MinMaxHeapLink<Element, Key>* link)
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{
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int current;
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int lastElement = link->fMinTree ? fMinLastElement : fMaxLastElement;
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Element** tree = link->fMinTree ? fMinElements : fMaxElements;
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while (true) {
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current = link->fIndex;
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int child = 2 * link->fIndex + 1;
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if (child < lastElement) {
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bool isSmaller = sCompare(sGetLink(tree[child])->fKey, link->fKey);
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if (isSmaller ^ !link->fMinTree)
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current = child;
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}
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child = 2 * link->fIndex + 2;
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if (child < lastElement) {
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bool isSmaller = sCompare(sGetLink(tree[child])->fKey,
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sGetLink(tree[current])->fKey);
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if (isSmaller ^ !link->fMinTree)
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current = child;
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}
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if (link->fIndex == current)
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break;
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ASSERT(sGetLink(tree[current])->fIndex == current);
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sGetLink(tree[current])->fIndex = link->fIndex;
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Element* element = tree[link->fIndex];
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tree[link->fIndex] = tree[current];
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tree[current] = element;
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link->fIndex = current;
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}
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if (2 * link->fIndex + 1 >= lastElement)
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_ChangeTree(link);
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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bool
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MIN_MAX_HEAP_CLASS_NAME::_ChangeTree(MinMaxHeapLink<Element, Key>* link)
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{
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int currentLastElement = link->fMinTree ? fMinLastElement : fMaxLastElement;
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int otherLastElement = link->fMinTree ? fMaxLastElement : fMinLastElement;
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Element** currentTree = link->fMinTree ? fMinElements : fMaxElements;
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Element** otherTree = link->fMinTree ? fMaxElements : fMinElements;
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if (otherLastElement <= 0) {
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ASSERT(currentLastElement == 1);
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return true;
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}
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ASSERT((link->fIndex - 1) / 2 < otherLastElement);
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Element* predecessor;
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if (2 * link->fIndex + 1 < otherLastElement) {
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predecessor = otherTree[2 * link->fIndex + 1];
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ASSERT(sGetLink(predecessor)->fIndex == 2 * link->fIndex + 1);
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} else if (link->fIndex < otherLastElement) {
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predecessor = otherTree[link->fIndex];
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ASSERT(sGetLink(predecessor)->fIndex == link->fIndex);
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} else {
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predecessor = otherTree[(link->fIndex - 1) / 2];
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ASSERT(sGetLink(predecessor)->fIndex == (link->fIndex - 1) / 2);
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}
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MinMaxHeapLink<Element, Key>* predecessorLink = sGetLink(predecessor);
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bool isSmaller = sCompare(predecessorLink->fKey, link->fKey);
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if (isSmaller ^ !link->fMinTree) {
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Element* element = currentTree[link->fIndex];
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currentTree[link->fIndex] = otherTree[predecessorLink->fIndex];
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otherTree[predecessorLink->fIndex] = element;
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int index = link->fIndex;
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link->fIndex = predecessorLink->fIndex;
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predecessorLink->fIndex = index;
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predecessorLink->fMinTree = !predecessorLink->fMinTree;
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link->fMinTree = !link->fMinTree;
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_MoveUp(link);
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return true;
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}
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return false;
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}
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MIN_MAX_HEAP_TEMPLATE_LIST
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void
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MIN_MAX_HEAP_CLASS_NAME::_RemoveLast(bool minTree)
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{
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bool deleteMin = fMaxLastElement < fMinLastElement;
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Element** tree = deleteMin ? fMinElements : fMaxElements;
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int& lastElement = deleteMin ? fMinLastElement : fMaxLastElement;
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ASSERT(lastElement > 0);
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lastElement--;
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if (lastElement == 0 && deleteMin == minTree)
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return;
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Element* element = tree[lastElement];
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if (minTree)
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fMinElements[0] = element;
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else
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fMaxElements[0] = element;
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MinMaxHeapLink<Element, Key>* link = sGetLink(element);
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link->fIndex = 0;
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link->fMinTree = minTree;
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_MoveDown(link);
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}
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#endif // KERNEL_UTIL_MIN_MAX_HEAP_H
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