[gnugo-devel] Another serious bugfix

[Gunnar Farneback]

This patch fixes an indexing out of bounds bug. Usually this is
harmless in practice, but at least on some architectures (in this case
Alpha) it can cause a crash. The patch also adds a relevant assertion.

- bugfix in strategic_penalty()

/Gunnar

Index: engine/influence.c
===================================================================
RCS file: /cvsroot/gnugo/gnugo/engine/influence.c,v
retrieving revision 1.47
diff -u -r1.47 influence.c
--- engine/influence.c  31 Mar 2002 20:46:47 -0000      1.47
+++ engine/influence.c  1 Apr 2002 12:19:24 -0000
@@ -1086,6 +1086,8 @@
   float bi = q->black_influence[m][n];
   float wi = q->white_influence[m][n];
 
+  ASSERT_ON_BOARD2(m, n);
+  
   if (bi > 0.0 && wi == 0.0)
     return BLACK;
 
Index: engine/value_moves.c
===================================================================
RCS file: /cvsroot/gnugo/gnugo/engine/value_moves.c,v
retrieving revision 1.22
diff -u -r1.22 value_moves.c
--- engine/value_moves.c        26 Mar 2002 21:32:59 -0000      1.22
+++ engine/value_moves.c        1 Apr 2002 12:19:25 -0000
@@ -1065,7 +1065,8 @@
    * whether all neighboring intersections belong to the opponent's moyo.
    */
   for (k = 0; k < 4; k++)
-    if (board[pos + delta[k]] != OTHER_COLOR(color)
+    if (ON_BOARD(pos + delta[k])
+       && board[pos + delta[k]] != OTHER_COLOR(color)
         && influence_moyo_color(pos + delta[k]) != OTHER_COLOR(color))
       return 0.0;
 
@@ -1110,11 +1111,15 @@
          return 0.0;
        /* Third line moves (or lower) are ok -- they try to live, not run
          * away.
+        *
+        * FIXME: Add an "edge_distance()" function in board.c which can
+        *        be used here.
          */
         if (gg_min(gg_min(I(pos), board_size-1 - I(pos)),
                    gg_min(J(pos), board_size-1 - J(pos)))
             < 3)
          return 0.0;
+       
        for (i = 0; i < 4; i++)
          if (board[target + delta[i]] == OTHER_COLOR(color)) {
            if (dragon[target + delta[i]].size == 1) {