Make path reversable in map_editor()

2 files changed, 19 insertions, 11 deletions

diff --git a/map.c b/map.c
index 005936f..85cc073 100644
--- a/map.c
+++ b/map.c
@@ -660,6 +660,8 @@ void map_editor(Map *map, size_t *width, size_t *height, Position *start, Positi
          *
          *    [d]    - Switch algorithms (A* or Dijsktra's)
          *
+         *    [r]    - Reverse path
+         *
          *    [s]    - Save the map to a plaintext file
          *
          *    [q]    - Exit the map editor
@@ -721,6 +723,10 @@ void map_editor(Map *map, size_t *width, size_t *height, Position *start, Positi
                       if (should_pathfind) path = path_func(dirs, *map, NULL, *width, *height, *start, *goal, visited, 0);
                       break;
 
+            case 'r':
+                      path_reverse(&path, *width, *height, start, goal);
+                      break;
+
             case 's':
                       curs_set(2);   /* Show the cursor */
                       echo();        /* Echo characters */
diff --git a/path.c b/path.c
index 450ea91..f604ec1 100644
--- a/path.c
+++ b/path.c
@@ -337,14 +337,19 @@ void path_free(Path path, size_t height) {
 }
 
 void path_reverse(Path *path, size_t width, size_t height, Position *start, Position *end) {
-    Path new_path = path_new(width, height);
-    if (new_path == NULL) error("Failed to allocate path\n");
-
-    Position cur = *end;
-    while (cur.x != start->x || cur.y != start->y) {
-        Position parent = (*path)[cur.y][cur.x];
-        new_path[parent.y][parent.x] = cur;
-        cur = parent;
+    if (*path != NULL) {
+        Path new_path = path_new(width, height);
+        if (new_path == NULL) error("Failed to allocate path\n");
+
+        Position cur = *end;
+        while (cur.x != start->x || cur.y != start->y) {
+            Position parent = (*path)[cur.y][cur.x];
+            new_path[parent.y][parent.x] = cur;
+            cur = parent;
+        }
+
+        path_free(*path, height);
+        *path = new_path;
     }
 
     /* Switch start and end around */
@@ -356,9 +361,6 @@ void path_reverse(Path *path, size_t width, size_t height, Position *start, Posi
     end->y   ^= start->y;
     start->y ^= end->y;
 
-    path_free(*path, height);
-    *path = new_path;
-
     return;
 }