--- src/sbin/hammer/misc.c	2008/01/17 04:59:48	1.1
+++ src/sbin/hammer/misc.c	2008/01/21 00:03:31	1.2
@@ -36,3 +36,51 @@
 
 #include "hammer.h"
 
+/*
+ * (taken from /usr/src/sys/vfs/hammer/hammer_btree.c)
+ *
+ * Compare two B-Tree elements, return -N, 0, or +N (e.g. similar to strcmp).
+ *
+ * Note that for this particular function a return value of -1, 0, or +1
+ * can denote a match if delete_tid is otherwise discounted.  A delete_tid
+ * of zero is considered to be 'infinity' in comparisons.
+ *
+ * See also hammer_rec_rb_compare() and hammer_rec_cmp() in hammer_object.c.
+ */
+int
+hammer_btree_cmp(hammer_base_elm_t key1, hammer_base_elm_t key2)
+{
+	if (key1->obj_id < key2->obj_id)
+		return(-4);
+	if (key1->obj_id > key2->obj_id)
+		return(4);
+
+	if (key1->rec_type < key2->rec_type)
+		return(-3);
+	if (key1->rec_type > key2->rec_type)
+		return(3);
+
+	if (key1->key < key2->key)
+		return(-2);
+	if (key1->key > key2->key)
+		return(2);
+
+	/*
+	 * A delete_tid of zero indicates a record which has not been
+	 * deleted yet and must be considered to have a value of positive
+	 * infinity.
+	 */
+	if (key1->delete_tid == 0) {
+		if (key2->delete_tid == 0)
+			return(0);
+		return(1);
+	}
+	if (key2->delete_tid == 0)
+		return(-1);
+	if (key1->delete_tid < key2->delete_tid)
+		return(-1);
+	if (key1->delete_tid > key2->delete_tid)
+		return(1);
+	return(0);
+}
+