From 296f3272e2bf8c51715bec9a161b037b09804148 Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@pond.sub.org>
Date: Fri, 17 Jan 2014 18:49:48 +0100
Subject: [PATCH] path: New DIR_BACK()

Actually pathfind.c's rev_dir() turned into a macro, to make it
available elsewhere.

Signed-off-by: Markus Armbruster <armbru@pond.sub.org>
---
 include/path.h            |  4 +++-
 src/lib/common/pathfind.c | 14 ++++----------
 2 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/include/path.h b/include/path.h
index 52a65885..5d83f32a 100644
--- a/include/path.h
+++ b/include/path.h
@@ -27,7 +27,7 @@
  *  path.h: Definitions for directions, paths, etc.
  *
  *  Known contributors to this file:
- *     Markus Armbruster, 2005-2011
+ *     Markus Armbruster, 2005-2014
  */
 
 #ifndef PATH_H
@@ -49,6 +49,8 @@
 #define DIR_FIRST	1
 #define DIR_LAST	6
 
+#define DIR_BACK(dir) ((dir) >= DIR_FIRST + 3 ? (dir) - 3 : (dir) + 3)
+
 #define MOB_MOVE	0
 #define MOB_MARCH	1
 #define MOB_RAIL	2
diff --git a/src/lib/common/pathfind.c b/src/lib/common/pathfind.c
index 2793aed4..759c7c88 100644
--- a/src/lib/common/pathfind.c
+++ b/src/lib/common/pathfind.c
@@ -27,7 +27,7 @@
  *  pathfind.c: Find cheapest paths
  *
  *  Known contributors to this file:
- *     Markus Armbruster, 2011
+ *     Markus Armbruster, 2014
  */
 
 #include <config.h>
@@ -325,13 +325,6 @@ y_in_dir(coord y, int dir)
     return yy;
 }
 
-static int
-rev_dir(int dir)
-{
-    assert(DIR_FIRST <= dir && dir <= DIR_LAST);
-    return dir >= DIR_FIRST + 3 ? dir - 3 : dir + 3;
-}
-
 /*
  * Set the current source and cost function.
  * SX,SY is the source.
@@ -456,8 +449,9 @@ path_find_route(char *buf, size_t bufsz,
 	    i = bufsz;
 	buf[--i] = dirch[d];
 	len++;
-	x = x_in_dir(x, rev_dir(d));
-	y = y_in_dir(y, rev_dir(d));
+	assert(DIR_FIRST <= d && d <= DIR_LAST);
+	x = x_in_dir(x, DIR_BACK(d));
+	y = y_in_dir(y, DIR_BACK(d));
     }
 
     assert(x == sx && y == sy);