101 lines
4.1 KiB
C++
101 lines
4.1 KiB
C++
/* Copyright (c) 2015, 2020 The Linux Foundation. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met:
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* * Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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* * Neither the name of The Linux Foundation, nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
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* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS
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* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
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* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE
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* OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN
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* IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#ifndef __LOC_HEAP__
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#define __LOC_HEAP__
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#include <stddef.h>
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#include <string.h>
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namespace loc_util {
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// abstract class to be implemented by client to provide a rankable class
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class LocRankable {
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public:
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virtual inline ~LocRankable() {}
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// method to rank objects of such type for sorting purposes.
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// The pointer of the input node would be stored in the heap.
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// >0 if ranks higher than the input;
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// ==0 if equally ranks with the input;
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// <0 if ranks lower than the input
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virtual int ranks(LocRankable& rankable) = 0;
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// convenient method to rank objects of such type for sorting purposes.
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inline bool outRanks(LocRankable& rankable) { return ranks(rankable) > 0; }
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};
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// opaque class to provide service implementation.
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class LocHeapNode;
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// a heap whose left and right children are not sorted. It is sorted only vertically,
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// i.e. parent always ranks higher than children, if they exist. Ranking algorithm is
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// implemented in Rankable. The reason that there is no sort between children is to
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// help beter balance the tree with lower cost. When a node is pushed to the tree,
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// it is guaranteed that the subtree that is smaller gets to have the new node.
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class LocHeap {
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protected:
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LocHeapNode* mTree;
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public:
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inline LocHeap() : mTree(NULL) {}
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~LocHeap();
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// push keeps the tree sorted by rank, it also tries to balance the
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// tree by adding the new node to the smaller of the subtrees.
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// node is reference to an obj that is managed by client, that client
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// creates and destroyes. The destroy should happen after the
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// node is popped out from the heap.
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void push(LocRankable& node);
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// Peeks the node data on tree top, which has currently the highest ranking
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// There is no change the tree structure with this operation
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// Returns NULL if the tree is empty, otherwise pointer to the node data of
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// the tree top.
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LocRankable* peek();
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// pop keeps the tree sorted by rank, but it does not try to balance
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// the tree.
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// Return - pointer to the node popped out, or NULL if heap is already empty
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LocRankable* pop();
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// navigating through the tree and find the node that ranks the same
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// as the input data, then remove it from the tree. Rank is implemented
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// by rankable obj.
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// returns the pointer to the node removed; or NULL (if failed).
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LocRankable* remove(LocRankable& rankable);
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#ifdef __LOC_UNIT_TEST__
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bool checkTree();
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uint32_t getTreeSize();
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#endif
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};
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} // namespace loc_util
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#endif //__LOC_HEAP__
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