Line data Source code
1 : /*
2 : * Copyright (c) 2007-2012 Niels Provos and Nick Mathewson
3 : *
4 : * Copyright (c) 2006 Maxim Yegorushkin <maxim.yegorushkin@gmail.com>
5 : *
6 : * Redistribution and use in source and binary forms, with or without
7 : * modification, are permitted provided that the following conditions
8 : * are met:
9 : * 1. Redistributions of source code must retain the above copyright
10 : * notice, this list of conditions and the following disclaimer.
11 : * 2. Redistributions in binary form must reproduce the above copyright
12 : * notice, this list of conditions and the following disclaimer in the
13 : * documentation and/or other materials provided with the distribution.
14 : * 3. The name of the author may not be used to endorse or promote products
15 : * derived from this software without specific prior written permission.
16 : *
17 : * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 : * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 : * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 : * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 : * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 : * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 : * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 : * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 : * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 : * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 : */
28 : #ifndef MINHEAP_INTERNAL_H_INCLUDED_
29 : #define MINHEAP_INTERNAL_H_INCLUDED_
30 :
31 : #include "event2/event-config.h"
32 : #include "evconfig-private.h"
33 : #include "event2/event.h"
34 : #include "event2/event_struct.h"
35 : #include "event2/util.h"
36 : #include "util-internal.h"
37 : #include "mm-internal.h"
38 :
39 : typedef struct min_heap
40 : {
41 : struct event** p;
42 : unsigned n, a;
43 : } min_heap_t;
44 :
45 : static inline void min_heap_ctor_(min_heap_t* s);
46 : static inline void min_heap_dtor_(min_heap_t* s);
47 : static inline void min_heap_elem_init_(struct event* e);
48 : static inline int min_heap_elt_is_top_(const struct event *e);
49 : static inline int min_heap_empty_(min_heap_t* s);
50 : static inline unsigned min_heap_size_(min_heap_t* s);
51 : static inline struct event* min_heap_top_(min_heap_t* s);
52 : static inline int min_heap_reserve_(min_heap_t* s, unsigned n);
53 : static inline int min_heap_push_(min_heap_t* s, struct event* e);
54 : static inline struct event* min_heap_pop_(min_heap_t* s);
55 : static inline int min_heap_adjust_(min_heap_t *s, struct event* e);
56 : static inline int min_heap_erase_(min_heap_t* s, struct event* e);
57 : static inline void min_heap_shift_up_(min_heap_t* s, unsigned hole_index, struct event* e);
58 : static inline void min_heap_shift_up_unconditional_(min_heap_t* s, unsigned hole_index, struct event* e);
59 : static inline void min_heap_shift_down_(min_heap_t* s, unsigned hole_index, struct event* e);
60 :
61 : #define min_heap_elem_greater(a, b) \
62 : (evutil_timercmp(&(a)->ev_timeout, &(b)->ev_timeout, >))
63 :
64 3 : void min_heap_ctor_(min_heap_t* s) { s->p = 0; s->n = 0; s->a = 0; }
65 0 : void min_heap_dtor_(min_heap_t* s) { if (s->p) mm_free(s->p); }
66 43 : void min_heap_elem_init_(struct event* e) { e->ev_timeout_pos.min_heap_idx = -1; }
67 651 : int min_heap_empty_(min_heap_t* s) { return 0u == s->n; }
68 0 : unsigned min_heap_size_(min_heap_t* s) { return s->n; }
69 648 : struct event* min_heap_top_(min_heap_t* s) { return s->n ? *s->p : 0; }
70 :
71 0 : int min_heap_push_(min_heap_t* s, struct event* e)
72 : {
73 0 : if (min_heap_reserve_(s, s->n + 1))
74 0 : return -1;
75 0 : min_heap_shift_up_(s, s->n++, e);
76 0 : return 0;
77 : }
78 :
79 : struct event* min_heap_pop_(min_heap_t* s)
80 : {
81 : if (s->n)
82 : {
83 : struct event* e = *s->p;
84 : min_heap_shift_down_(s, 0u, s->p[--s->n]);
85 : e->ev_timeout_pos.min_heap_idx = -1;
86 : return e;
87 : }
88 : return 0;
89 : }
90 :
91 0 : int min_heap_elt_is_top_(const struct event *e)
92 : {
93 0 : return e->ev_timeout_pos.min_heap_idx == 0;
94 : }
95 :
96 0 : int min_heap_erase_(min_heap_t* s, struct event* e)
97 : {
98 0 : if (-1 != e->ev_timeout_pos.min_heap_idx)
99 : {
100 0 : struct event *last = s->p[--s->n];
101 0 : unsigned parent = (e->ev_timeout_pos.min_heap_idx - 1) / 2;
102 : /* we replace e with the last element in the heap. We might need to
103 : shift it upward if it is less than its parent, or downward if it is
104 : greater than one or both its children. Since the children are known
105 : to be less than the parent, it can't need to shift both up and
106 : down. */
107 0 : if (e->ev_timeout_pos.min_heap_idx > 0 && min_heap_elem_greater(s->p[parent], last))
108 0 : min_heap_shift_up_unconditional_(s, e->ev_timeout_pos.min_heap_idx, last);
109 : else
110 0 : min_heap_shift_down_(s, e->ev_timeout_pos.min_heap_idx, last);
111 0 : e->ev_timeout_pos.min_heap_idx = -1;
112 0 : return 0;
113 : }
114 0 : return -1;
115 : }
116 :
117 : int min_heap_adjust_(min_heap_t *s, struct event *e)
118 : {
119 : if (-1 == e->ev_timeout_pos.min_heap_idx) {
120 : return min_heap_push_(s, e);
121 : } else {
122 : unsigned parent = (e->ev_timeout_pos.min_heap_idx - 1) / 2;
123 : /* The position of e has changed; we shift it up or down
124 : * as needed. We can't need to do both. */
125 : if (e->ev_timeout_pos.min_heap_idx > 0 && min_heap_elem_greater(s->p[parent], e))
126 : min_heap_shift_up_unconditional_(s, e->ev_timeout_pos.min_heap_idx, e);
127 : else
128 : min_heap_shift_down_(s, e->ev_timeout_pos.min_heap_idx, e);
129 : return 0;
130 : }
131 : }
132 :
133 0 : int min_heap_reserve_(min_heap_t* s, unsigned n)
134 : {
135 0 : if (s->a < n)
136 : {
137 : struct event** p;
138 0 : unsigned a = s->a ? s->a * 2 : 8;
139 0 : if (a < n)
140 0 : a = n;
141 0 : if (!(p = (struct event**)mm_realloc(s->p, a * sizeof *p)))
142 0 : return -1;
143 0 : s->p = p;
144 0 : s->a = a;
145 : }
146 0 : return 0;
147 : }
148 :
149 0 : void min_heap_shift_up_unconditional_(min_heap_t* s, unsigned hole_index, struct event* e)
150 : {
151 0 : unsigned parent = (hole_index - 1) / 2;
152 : do
153 : {
154 0 : (s->p[hole_index] = s->p[parent])->ev_timeout_pos.min_heap_idx = hole_index;
155 0 : hole_index = parent;
156 0 : parent = (hole_index - 1) / 2;
157 0 : } while (hole_index && min_heap_elem_greater(s->p[parent], e));
158 0 : (s->p[hole_index] = e)->ev_timeout_pos.min_heap_idx = hole_index;
159 0 : }
160 :
161 0 : void min_heap_shift_up_(min_heap_t* s, unsigned hole_index, struct event* e)
162 : {
163 0 : unsigned parent = (hole_index - 1) / 2;
164 0 : while (hole_index && min_heap_elem_greater(s->p[parent], e))
165 : {
166 0 : (s->p[hole_index] = s->p[parent])->ev_timeout_pos.min_heap_idx = hole_index;
167 0 : hole_index = parent;
168 0 : parent = (hole_index - 1) / 2;
169 : }
170 0 : (s->p[hole_index] = e)->ev_timeout_pos.min_heap_idx = hole_index;
171 0 : }
172 :
173 0 : void min_heap_shift_down_(min_heap_t* s, unsigned hole_index, struct event* e)
174 : {
175 0 : unsigned min_child = 2 * (hole_index + 1);
176 0 : while (min_child <= s->n)
177 : {
178 0 : min_child -= min_child == s->n || min_heap_elem_greater(s->p[min_child], s->p[min_child - 1]);
179 0 : if (!(min_heap_elem_greater(e, s->p[min_child])))
180 0 : break;
181 0 : (s->p[hole_index] = s->p[min_child])->ev_timeout_pos.min_heap_idx = hole_index;
182 0 : hole_index = min_child;
183 0 : min_child = 2 * (hole_index + 1);
184 : }
185 0 : (s->p[hole_index] = e)->ev_timeout_pos.min_heap_idx = hole_index;
186 0 : }
187 :
188 : #endif /* MINHEAP_INTERNAL_H_INCLUDED_ */
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