Index: obj_hash.h
===================================================================
--- obj_hash.h	(revision 14748)
+++ obj_hash.h	(revision 14749)
@@ -69,3 +69,16 @@
 	l = floor(ang);
 	return murmurhash(&l, sizeof(l));
 }
+
+#define pcb_hash_str(s) ((s) == NULL ? 0 : strhash(s))
+
+/* hash relative x and y within an element */
+#define pcb_hash_element_ox(e, c) ((e) == NULL ? pcb_hash_coord(c) : pcb_hash_coord(c - e->MarkX))
+#define pcb_hash_element_oy(e, c) ((e) == NULL ? pcb_hash_coord(c) : pcb_hash_coord(c - e->MarkY))
+
+/* compare two fields and return 0 if they are equal */
+#define pcb_field_neq(s1, s2, f) ((s1)->f != (s2)->f)
+
+#define pcb_element_offs(e,ef, s,sf) ((e == NULL) ? (s)->sf : ((s)->sf) - ((e)->ef))
+#define pcb_element_neq_offsx(e1, x1, e2, x2, f) (pcb_element_offs(e1, MarkX, x1, f) != pcb_element_offs(e2, MarkX, x2, f))
+#define pcb_element_neq_offsy(e1, y1, e2, y2, f) (pcb_element_offs(e1, MarkY, y1, f) != pcb_element_offs(e2, MarkY, y2, f))