Add original unix v6

source/iolib/alloc.c

@@ -0,0 +1,75 @@
+#
+/*
+ * C library -- alloc/free
+ */
+
+#define	logical	char *
+
+struct fb {
+	logical	size;
+	char	*next;
+};
+
+int	freelist[] {
+	0,
+	-1,
+};
+logical	slop	2;
+
+alloc(asize)
+logical asize;
+{
+	register logical size;
+	register logical np;
+	register logical cp;
+
+	if ((size = asize) == 0)
+		return(0);
+	size =+ 3;
+	size =& ~01;
+	for (;;) {
+		for (cp=freelist; (np= cp->next) != -1; cp=np) {
+			if (np->size>=size) {
+				if (size+slop >= np->size) {
+					cp->next = np->next;
+					return(&np->next);
+				}
+				cp = cp->next = np+size;
+				cp->size = np->size - size;
+				cp->next = np->next;
+				np->size = size;
+				return(&np->next);
+			}
+		}
+		asize = size<1024? 1024: size;
+		if ((cp = sbrk(asize)) == -1) {
+			return (-1);
+		}
+		cp->size = asize;
+		free(&cp->next);
+	}
+}
+
+free(aptr)
+char *aptr;
+{
+	register logical ptr;
+	register logical cp;
+	register logical np;
+
+	ptr = aptr-2;
+	cp = freelist;
+	while ((np = cp->next) < ptr)
+		cp = np;
+	if (ptr+ptr->size == np) {
+		ptr->size =+ np->size;
+		ptr->next = np->next;
+		np = ptr;
+	} else
+		ptr->next = np;
+	if (cp+cp->size == ptr) {
+		cp->size =+ ptr->size;
+		cp->next = ptr->next;
+	} else
+		cp->next = ptr;
+}