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
|
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define EFULL 2
#define EMPTY 3
/* Queue stuff */
typedef struct {
int head;
int tail;
int len;
int cap;
int *buff;
} queue_t;
/* Queue functions */
int queue_init(queue_t *q, size_t cap)
{
/* Make the struct and set i to zero */
memset(q, 0, sizeof(queue_t));
/* Allocate the buffer */
q->buff = (int *) malloc(cap * sizeof(int));
if ( q->buff == NULL ) {
return 1;
}
/* Set capacity, the rest should be zero form memset */
q->cap = cap;
return 0;
}
void queue_free(queue_t *q)
{
/* Free the heap buffer */
free(q->buff);
}
int queue_place(queue_t *q, int val)
{
/* Check if full */
printf("len: %d\n", q->len);
if ( q->len >= q->cap) {
printf("ERR: Full\n");
return EFULL;
}
/* Add to queue */
q->buff[q->head] = val;
/* Increase values */
q->head = (q->head+1) % q->cap;
q->len++;
return 0;
}
int queue_get(queue_t *q, int *val)
{
/* Check if empty */
if ( !q->len ) {
printf("ERR: Empty\n");
return EMPTY;
}
/* Read value */
if ( val != NULL ){
*val = q->buff[q->tail];
}
/* Decrease values */
q->tail = (q->tail+1) % q->cap;
q->len--;
return 0;
}
int main(void)
{
int in;
char com;
queue_t q;
queue_init(&q, 16);
for (;;) {
/* Read a command */
scanf("%c", &com);
if ( com == 'w') {
printf("> ");
scanf("%d", &in);
queue_place(&q, in);
} else if ( com == 'r' ) {
queue_get(&q, &in);
printf("%d\n", in);
} else if ( com == 'q' ) {
break;
}
}
queue_free(&q);
}
|
