The Net solver now makes use of barrier information when applied to

a typed-in grid.

[originally from svn r5827]

diff --git a/net.c b/net.c
index 3520483adfb40d979a092992f358d05b88304c7c..b5134a9473ca63ada16690b1f1a3cbe650c29a29 100644 (file)
--- a/net.c
+++ b/net.c
@@ -415,7 +415,8 @@ static int todo_get(struct todo *todo) {
     return ret;
 }
 
-static int net_solver(int w, int h, unsigned char *tiles, int wrapping)
+static int net_solver(int w, int h, unsigned char *tiles,
+                     unsigned char *barriers, int wrapping)
 {
     unsigned char *tilestate;
     unsigned char *edgestate;
@@ -522,6 +523,30 @@ static int net_solver(int w, int h, unsigned char *tiles, int wrapping)
        }
     }
 
+    /*
+     * If we have barriers available, we can mark those edges as
+     * closed too.
+     */
+    if (barriers) {
+       for (y = 0; y < h; y++) for (x = 0; x < w; x++) {
+           int d;
+           for (d = 1; d <= 8; d += d) {
+               if (barriers[y*w+x] & d) {
+                   int x2, y2;
+                   /*
+                    * In principle the barrier list should already
+                    * contain each barrier from each side, but
+                    * let's not take chances with our internal
+                    * consistency.
+                    */
+                   OFFSETWH(x2, y2, x, y, d, w, h);
+                   edgestate[(y*w+x) * 5 + d] = 2;
+                   edgestate[(y2*w+x2) * 5 + F(d)] = 2;
+               }
+           }
+       }
+    }
+
     /*
      * Since most deductions made by this solver are local (the
      * exception is loop avoidance, where joining two tiles
@@ -1264,7 +1289,7 @@ static char *new_game_desc(game_params *params, random_state *rs,
        /*
         * Run the solver to check unique solubility.
         */
-       while (!net_solver(w, h, tiles, params->wrapping)) {
+       while (!net_solver(w, h, tiles, NULL, params->wrapping)) {
            int n = 0;
 
            /*
@@ -1641,7 +1666,8 @@ static game_state *solve_game(game_state *state, game_aux_info *aux,
         * not yield a complete solution.
         */
        ret = dup_game(state);
-       net_solver(ret->width, ret->height, ret->tiles, ret->wrapping);
+       net_solver(ret->width, ret->height, ret->tiles,
+                  ret->barriers, ret->wrapping);
     } else {
        assert(aux->width == state->width);
        assert(aux->height == state->height);