77 lines
1.2 KiB
C
77 lines
1.2 KiB
C
/*
|
|
* (c) copyright 1987 by the Vrije Universiteit, Amsterdam, The Netherlands.
|
|
* See the copyright notice in the ACK home directory, in the file "Copyright".
|
|
*/
|
|
#include "top.h"
|
|
#include "queue.h"
|
|
|
|
empty_queue(q)
|
|
register queue q;
|
|
{
|
|
q->head = q->tail = (instr_p) 0;
|
|
q->qlen = 0;
|
|
}
|
|
|
|
int empty(q)
|
|
queue q;
|
|
{
|
|
return q->qlen == 0;
|
|
}
|
|
|
|
remove_head(q)
|
|
register queue q;
|
|
{
|
|
if ( (q->head = q->head->fw) == (instr_p) 0) {
|
|
q->tail = (instr_p) 0;
|
|
} else {
|
|
q->head->bw = (instr_p) 0;
|
|
}
|
|
q->qlen--;
|
|
}
|
|
|
|
add(q,instr)
|
|
register queue q;
|
|
register instr_p instr;
|
|
{
|
|
if (q->qlen++ == 0) {
|
|
q->head = q->tail = instr;
|
|
instr->bw = (instr_p) 0;
|
|
} else {
|
|
q->tail->fw = instr;
|
|
instr->bw = q->tail;
|
|
q->tail = instr;
|
|
}
|
|
instr->fw = (instr_p) 0;
|
|
}
|
|
|
|
insert(q,instr)
|
|
register queue q;
|
|
register instr_p instr;
|
|
{
|
|
if (q->qlen++ == 0) {
|
|
q->head = q->tail = instr;
|
|
instr->fw = (instr_p) 0;
|
|
} else {
|
|
q->head->bw = instr;
|
|
instr->fw = q->head;
|
|
q->head = instr;
|
|
}
|
|
instr->bw = (instr_p) 0;
|
|
}
|
|
|
|
join_queues(q1,q2)
|
|
register queue q1,q2;
|
|
{
|
|
if (q1->qlen > 0) {
|
|
q2->qlen += q1->qlen;
|
|
q1->tail->fw = q2->head;
|
|
if (q2->qlen > 0) {
|
|
q2->head->bw = q1->tail;
|
|
} else {
|
|
q2->tail = q1->tail;
|
|
}
|
|
q2->head = q1->head;
|
|
empty_queue(q1);
|
|
}
|
|
}
|