Index: obj_hash.h
===================================================================
--- obj_hash.h	(nonexistent)
+++ obj_hash.h	(revision 14733)
@@ -0,0 +1,62 @@
+/*
+ *                            COPYRIGHT
+ *
+ *  pcb-rnd, interactive printed circuit board design
+ *  Copyright (C) 2017, 2018 Tibor 'Igor2' Palinkas
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ *  Contact:
+ *    Project page: http://repo.hu/projects/pcb-rnd
+ *    lead developer: email to pcb-rnd (at) igor2.repo.hu
+ *    mailing list: pcb-rnd (at) list.repo.hu (send "subscribe")
+ */
+
+#include <genht/hash.h>
+#include <genlist/gendlist.h>
+
+/* compare two strings and return 0 if they are equal. NULL == NULL means equal. */
+PCB_INLINE int pcb_neqs(const char *s1, const char *s2)
+{
+	if ((s1 == NULL) && (s2 == NULL)) return 0;
+	if ((s1 == NULL) || (s2 == NULL)) return 1;
+	return strcmp(s1, s2) != 0;
+}
+
+PCB_INLINE unsigned pcb_hash_coord(pcb_coord_t c)
+{
+	return murmurhash(&(c), sizeof(pcb_coord_t));
+}
+
+PCB_INLINE unsigned pcb_hash_cx(const pcb_host_trans_t *tr, pcb_coord_t c)
+{
+	c -= tr->ox;
+	return murmurhash(&(c), sizeof(pcb_coord_t));
+}
+
+PCB_INLINE unsigned pcb_hash_cy(const pcb_host_trans_t *tr, pcb_coord_t c)
+{
+	c -= tr->oy;
+	return murmurhash(&(c), sizeof(pcb_coord_t));
+}
+
+PCB_INLINE unsigned pcb_hash_angle(const pcb_host_trans_t *tr, pcb_angle_t ang)
+{
+	long l;
+	ang -= tr->rot;
+	ang *= 10000;
+	l = floor(ang);
+	return murmurhash(&l, sizeof(l));
+}