-
Notifications
You must be signed in to change notification settings - Fork 1
/
CalendarQueue.c
218 lines (203 loc) · 6.82 KB
/
CalendarQueue.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
#include "CalendarQueue.h"
#include "stdio.h"
#include "stdlib.h"
#include "Node.h"
enum BOOLEAN{FALSE, TRUE};
struct calendar_queue {
int firstsub;
List* bucket;
double buckettop;
double width;
int nbuckets;
int qsize;
int lastbucket;
double lastprio;
int top_threshold;
int bot_threshold;
int resizeenabled;
};
int mask_modulo(int m, int n) { return m & (n - 1);}
void localinit(CalendarQueue* q, int qbase, int nbuck,
double bwidth, double startprio) {
int i = 0;
long int n = 0;
/* Set position and size of new queue. */
q->firstsub = qbase;
q->bucket = &POOL[qbase];
q->width = bwidth;
q->nbuckets = nbuck;
//Calculate bit mask for modulo nbuckets operation; ???
/* Initialize as empty. */
q->qsize = 0;
for(i = 0; i < q->nbuckets; ++i) q->bucket[i] = NULL;
/* Set up initial position in queue. */
q->lastprio = startprio;
n = (long int)startprio/ q->width;
/* Virtual bucket */
q->lastbucket = mask_modulo(n, q->nbuckets);
q->buckettop = (n + 1) * q->width + 0.5 * q->width;
/* Set up queue size change thresholds. */
q->bot_threshold = q->nbuckets/2 - 2;
q->top_threshold = 2 * q->nbuckets;
}
CalendarQueue* initqueue() {
CalendarQueue* init_q = (CalendarQueue*)malloc(sizeof(CalendarQueue));
localinit(init_q, 0, 2, 1.0, 0.0);
init_q->resizeenabled = TRUE;
return init_q;
}
double newwidth(CalendarQueue* q) {
/* This calculates the width to use for buckets. */
int nsamples;
/* Decide how many queue elements to sample. */
if(q->qsize < 2) return(1.0);
if(q->qsize <= 5)
nsamples = q->qsize;
else
nsamples = 5 + q->qsize/10;
if(nsamples > 25) nsamples = 25;
double lastprio = q->lastprio;
int lastbucket = q->lastbucket;
double buckettop = q->buckettop;
q->resizeenabled = FALSE;
List* dqsamples = makelist();
double* samplesprio = (double*)malloc(sizeof(double) * nsamples);
for(int i = 0; i < nsamples; ++i) {
node* n = dequeue(q);
add(n, dqsamples);
samplesprio[i] = n->endTime;
}
for(int i = 0; i < nsamples; ++i) {
node* n = delete(*dqsamples, dqsamples);
enqueue(n, n->endTime, q);
}
destroy(dqsamples);
q->lastprio = lastprio;
q->lastbucket = lastbucket;
q->buckettop = buckettop;
q->resizeenabled = TRUE;
double sum = 0;
for(int i = 0; i < nsamples - 1; ++i) {
sum += (samplesprio[i + 1] - samplesprio[i]);
}
double avg_seperation = sum / (nsamples - 1);
int m = 0;
sum = 0;
for(int i = 0; i < nsamples - 1; ++i) {
double spr = samplesprio[i + 1] - samplesprio[i];
if(spr < 2*avg_seperation) {
sum += spr;
++m;
}
}
double final_seperation = (sum == 0)? (1.0 / 3) : sum / m;
free(samplesprio);
return(3.0 * final_seperation);
}
void resize(CalendarQueue* q, int newsize)
/* This copies the queue onto a calendar with newsize
buckets. The new bucket array is on the opposite
end of the array a[QSPACE] from the original. */
{
double bwidth;
int i;
int oldnbuckets;
List * oldbucket;
if (q->resizeenabled == FALSE) return;
bwidth = newwidth(q); /* Find new bucket width. */
/* Save location and size of old calendar for use
when copying calendar. */
oldbucket = q->bucket; oldnbuckets = q->nbuckets;
/* Initialize new calendar. */
if(q->firstsub == 0)
localinit(q, QSPACE-newsize, newsize, bwidth, q->lastprio);
else
localinit(q, 0, newsize, bwidth, q->lastprio);
q->resizeenabled = TRUE;
/* Copy queue elements to new calendar. */
for (i = oldnbuckets - 1; i >= 0; --i) {
node* current = oldbucket[i];
while (current != NULL) {
node* next = current->next;
enqueue(current, current->endTime, q);
current = next;
}
//Transfer elements from bucket i to new calendar
//by enqueueing them;
}
}
void enqueue(node* entry, double priority, CalendarQueue* q)
/* This adds one entry to the queue. */
{
int i;
/* Calculate the number of the bucket in which to
place the new entry. */
i = (long int)priority/ q->width; /* Find virtual bucket.*/
i = i % q->nbuckets; /* Find actual bucket. */
add(entry, &(q->bucket[i])); /*Insert entry into bucket i in sorted list. */
++(q->qsize); /* Update record of queue size. */
/* Double the calendar size if needed. */
if (q->qsize > q->top_threshold) resize(q, 2 * q->nbuckets);
}
struct node* dequeue(CalendarQueue* q)
/* This removes the lowest priority node from the
queue and returns a pointer to the node containing
it. */
{
register int i;
if (q->qsize == 0) return(NULL);
for (i = q->lastbucket; ; ) /* Search buckets */
{
/* Check bucket i */
if (q->bucket[i] != NULL && q->bucket[i]->endTime < q->buckettop)
{ /* Item to dequeue has been found. */
node* dequeue_i = delete(q->bucket[i], &(q->bucket[i]));
/* Update position on calendar. */
q->lastbucket = i; q->lastprio = dequeue_i->endTime;
--(q->qsize);
/* Halve calendar size if needed. */
if (q->qsize < q->bot_threshold) resize(q, q->nbuckets/2);
return dequeue_i;
}
else{/* Prepare to check next bucket or else go to a direct search. */
++i;
if(i == q->nbuckets) i = 0;
q->buckettop += q->width;
if(i == q->lastbucket) break; /* Go to direct search */
}
}
/* Directly search for minimum priority event. */
int firstprio = TRUE;
int lowestprio = 0;
int lowestbucket = 0;
for(int i = 0; i < q->nbuckets; ++i) {
if (q->bucket[i] == NULL) continue;
if(firstprio) {
lowestbucket = i;
lowestprio = q->bucket[i]->endTime;
firstprio = FALSE;
}
if (q->bucket[i]->endTime < lowestprio) {
lowestbucket = i;
lowestprio = q->bucket[i]->endTime;
}
}
q->lastbucket = lowestbucket;
q->lastprio = lowestprio;
int vbucket = (int)(lowestprio / (q->width));
q->buckettop = (vbucket + 1) * q->width + 0.5 * q->width;
return(dequeue(q)); /* Resume search at minnode. */
}
void display_queue(CalendarQueue* q) {
printf("Calendar Queue: \n");
printf("First subarray: %d; Bucket's width: %.2lf; Number of buckets: %d; \n", q->firstsub,
q->width, q->nbuckets);
printf("Queue's size: %d; Top threshold: %d; Bottom threshold: %d;", q->qsize,
q->top_threshold, q->bot_threshold);
for(int i = 0; i < q->nbuckets; ++i) {
printf("\n |\n v\n");
printf("Bucket [%d]: ", i);
display(&(q->bucket[i]), 15);
}
printf("\n");
}