78 lines
2.9 KiB
C
78 lines
2.9 KiB
C
/***
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* @Author: 张鹏春
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* @Team: 兰心开源
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* @Date: 2023-09-11 20:25:05
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*/
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/*
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* Copyright (c) 2020 Huawei Technologies Co.,Ltd.
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*
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* openGauss is licensed under Mulan PSL v2.
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* You can use this software according to the terms and conditions of the Mulan PSL v2.
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* You may obtain a copy of Mulan PSL v2 at:
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*
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* http://license.coscl.org.cn/MulanPSL2
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*
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* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
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* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
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* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
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* See the Mulan PSL v2 for more details.
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* ---------------------------------------------------------------------------------------
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*
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* binaryheap.h
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* A simple binary heap implementation
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*
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*
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* IDENTIFICATION
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* src/include/lib/binaryheap.h
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*
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* ---------------------------------------------------------------------------------------
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*/
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#ifndef BINARYHEAP_H
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#define BINARYHEAP_H
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/*
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* For a max-heap, the comparator must return <0 iff a < b, 0 iff a == b,
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* and >0 iff a > b. For a min-heap, the conditions are reversed.
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*/
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typedef int (*binaryheap_comparator)(Datum a, Datum b, void* arg);
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/*
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* binaryheap
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*
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* bh_size how many nodes are currently in "nodes"
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* bh_space how many nodes can be stored in "nodes"
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* bh_has_heap_property no unordered operations since last heap build
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* bh_compare comparison function to define the heap property
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* bh_arg user data for comparison function
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* bh_nodes variable-length array of "space" nodes
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*/
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typedef struct binaryheap {
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int bh_size; /* number of nodes currently in heap */
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int bh_space; /* current size of bh_nodes array */
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bool bh_has_heap_property; /* debugging cross-check */
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binaryheap_comparator bh_compare; /* comparison function */
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void* bh_arg; /* extra argument for comparison function */
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Datum bh_nodes[FLEXIBLE_ARRAY_MEMBER]; /* VARIABLE LENGTH ARRAY */
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} binaryheap;
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extern binaryheap* binaryheap_allocate(int capacity, binaryheap_comparator compare, void* arg); /* allocates memory */
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extern void binaryheap_reset(binaryheap* heap); /* reset heap, but not free memory*/
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extern void binaryheap_free(binaryheap* heap); /* frees memory */
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extern void binaryheap_add_unordered(binaryheap* heap, Datum d);
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/* add element to heap ,but may violate heap property */
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extern void binaryheap_build(binaryheap* heap); /* builds heap property */
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extern void binaryheap_add(binaryheap* heap, Datum d); /*add element to heap*/
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extern Datum binaryheap_first(binaryheap* heap); /* returns first element */
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extern Datum binaryheap_remove_first(binaryheap* heap); /* removes first element */
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extern void binaryheap_replace_first(binaryheap* heap, Datum d); /* replaces first element */
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#define binaryheap_empty(h) ((h)->bh_size == 0) /* judge whether heap is empty*/
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#endif /* BINARYHEAP_H */
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