Initial revision

mach/proto/top/queue.c

@@ -0,0 +1,72 @@
+#include "top.h"
+#include "queue.h"
+
+empty_queue(q)
+	queue q;
+{
+	q->head = q->tail = (instr_p) 0;
+	q->qlen = 0;
+}
+
+int empty(q)
+	queue q;
+{
+	return q->qlen == 0;
+}
+
+remove_head(q)
+	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)
+	queue q;
+	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)
+	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);
+	}
+}