Initial revision

lang/pc/libpc/new.c

@@ -0,0 +1,66 @@
+/*
+ * (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
+ *
+ *          This product is part of the Amsterdam Compiler Kit.
+ *
+ * Permission to use, sell, duplicate or disclose this software must be
+ * obtained in writing. Requests for such permissions may be sent to
+ *
+ *      Dr. Andrew S. Tanenbaum
+ *      Wiskundig Seminarium
+ *      Vrije Universiteit
+ *      Postbox 7161
+ *      1007 MC Amsterdam
+ *      The Netherlands
+ *
+ */
+
+/* Author: J.W. Stevenson */
+
+extern		_sav();
+extern		_rst();
+
+#define assert()	/* nothing */
+#define	UNDEF		0x8000
+
+struct adm {
+	struct adm	*next;
+	int		size;
+};
+
+struct adm	*_lastp = 0;
+struct adm	*_highp = 0;
+
+_new(n,pp) int n; struct adm **pp; {
+	struct adm *p,*q;
+
+	n = ((n+sizeof(*p)-1) / sizeof(*p)) * sizeof(*p);
+	if ((p = _lastp) != 0)
+		do {
+			q = p->next;
+			if (q->size >= n) {
+				assert(q->size%sizeof(adm) == 0);
+				if ((q->size -= n) == 0) {
+					if (p == q)
+						p = 0;
+					else
+						p->next = q->next;
+					if (q == _highp)
+						_highp = p;
+				}
+				_lastp = p;
+				p = (struct adm *)((char *)q + q->size);
+				q = (struct adm *)((char *)p + n);
+				goto initialize;
+			}
+			p = q;
+		} while (p != _lastp);
+	/*no free block big enough*/
+	_sav(&p);
+	q = (struct adm *)((char *)p + n);
+	_rst(&q);
+initialize:
+	*pp = p;
+	while (p < q)
+		*((int *)p)++ = UNDEF;
+}