1/*
2 * Copyright (c) 2015, Intel Corporation
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * * Redistributions of source code must retain the above copyright notice,
8 * this list of conditions and the following disclaimer.
9 * * Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 * * Neither the name of Intel Corporation nor the names of its contributors
13 * may be used to endorse or promote products derived from this software
14 * without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28
29#ifndef PQUEUE_H
30#define PQUEUE_H
31
32#include "ue2common.h"
33
34static really_inline u32
35pq_left(u32 i) {
36 return (i << 1) + 1;
37}
38
39static really_inline u32
40pq_right(u32 i) {
41 return (i << 1) + 2;
42}
43
44static really_inline
45u32 pq_parent(u32 i) {
46 return (i - 1) >> 1;
47}
48
49static really_inline
50void pq_sift(PQ_T *items, u32 start, u32 end) {
51 u32 j = start;
52 PQ_T j_temp = items[j];
53
54 while (pq_left(j) < end) {
55 u32 max_child;
56
57 if (pq_right(j) < end && PQ_COMP(items, pq_right(j), pq_left(j))) {
58 max_child = pq_right(j);
59 } else {
60 max_child = pq_left(j);
61 }
62
63 if (PQ_COMP_B(items, max_child, j_temp)) {
64 items[j] = items[max_child];
65 j = max_child;
66 } else {
67 /* j is already less than its children. We know heap property
68 * is already maintained for children we are done */
69 break;
70 }
71 }
72 items[j] = j_temp;
73}
74
75static really_inline
76PQ_T *pq_top(PQ_T *items) {
77 return items;
78}
79
80static really_inline
81void pq_pop(PQ_T *items, u32 item_count) {
82 item_count--;
83 items[0] = items[item_count];
84 pq_sift(items, 0, item_count);
85}
86
87static really_inline
88void pq_insert(PQ_T *items, u32 item_count, PQ_T new_item) {
89 u32 pos = item_count;
90 while (pos) {
91 u32 parent = pq_parent(pos);
92 if (!PQ_COMP_B(items, parent, new_item)) {
93 items[pos] = items[parent];
94 pos = parent;
95 } else {
96 break;
97 }
98 }
99 items[pos] = new_item;
100}
101
102static really_inline
103void pq_replace_top(PQ_T *items, u32 item_count, PQ_T new_item) {
104 items[0] = new_item;
105 pq_sift(items, 0, item_count);
106}
107
108#endif
109
110