[gnugo-devel] != EMPTY or IS_COLOR ?

[Teun Burgers]

In the days of the 2-D board
!= EMPTY implied BLACK || WHITE.
With the 1-D board it can also mean GRAY,
unless you made sure that the point is ON_BOARD.

This patch defines a new macro IS_COLOR and as
an example replace != EMPTY tests in worm.c
with IS_COLOR tests. I think this is
safer in the long run

Teun

Index: engine/gnugo.h
===================================================================
RCS file: /cvsroot/gnugo/gnugo/engine/gnugo.h,v
retrieving revision 1.15
diff -u -r1.15 gnugo.h
--- engine/gnugo.h      2001/10/11 15:39:37     1.15
+++ engine/gnugo.h      2001/10/11 20:08:44
@@ -63,6 +63,7 @@
 
 
 #define OTHER_COLOR(color)  (WHITE+BLACK-(color))
+#define IS_COLOR(arg)  ((arg) == WHITE || (arg) == BLACK)
 
 /* Return codes for reading functions */
 
Index: engine/worm.c
===================================================================
RCS file: /cvsroot/gnugo/gnugo/engine/worm.c,v
retrieving revision 1.14
diff -u -r1.14 worm.c
--- engine/worm.c       2001/10/10 19:05:06     1.14
+++ engine/worm.c       2001/10/11 20:08:54
@@ -488,8 +488,8 @@
     for (n = 0; n < board_size; n++) {
       int pos = POS(m, n);
       if (!is_same_worm(pos, SOUTH(pos))
-         && board[pos] != EMPTY
-         && board[SOUTH(pos)] != EMPTY) {
+         && IS_COLOR(board[pos])
+         && IS_COLOR(board[SOUTH(pos)])) {
         if (worm[pos].attack_codes[0] != 0
            && worm[SOUTH(pos)].attack_codes[0] != 0) {
          if (worm[pos].defend_codes[0] == 0
@@ -511,8 +511,8 @@
     for (n = 0; n < board_size-1; n++) {
       int pos = POS(m, n);
       if (!is_same_worm(pos, EAST(pos))
-         && board[pos] != EMPTY
-         && board[EAST(pos)] != EMPTY) {
+         && IS_COLOR(board[pos])
+         && IS_COLOR(board[EAST(pos)])) {
         if (worm[pos].attack_codes[0] != 0
            && worm[EAST(pos)].attack_codes[0] != 0) {
          if (worm[pos].defend_codes[0] == 0
@@ -632,7 +632,7 @@
       worm[pos].invincible = 0;
       worm[pos].unconditional_status = UNKNOWN;
       worm[pos].effective_size = 0.0;
-      if (board[pos] != EMPTY) {
+      if (IS_COLOR(board[pos])) {
        worm[pos].liberties = countlib(pos);
        worm[pos].size = countstones(pos);
        propagate_worm(pos);
@@ -739,7 +739,7 @@
   /* Propagate the effective size values all over the worms. */
   for (m = 0; m < board_size; m++)
     for (n = 0; n < board_size; n++)
-      if (BOARD(m, n) != EMPTY && is_worm_origin(POS(m, n), POS(m, n)))
+      if (IS_COLOR(BOARD(m, n)) && is_worm_origin(POS(m, n), POS(m, n)))
        propagate_worm(POS(m, n));
 }
 
@@ -1003,7 +1003,7 @@
              int bb = libs[k] + delta[l];
 
              if (!ON_BOARD(bb)
-                 || board[bb] != EMPTY
+                 || IS_COLOR(board[bb])
                  || liberty_of_string(bb, pos))
                continue;
 
@@ -1065,7 +1065,7 @@
            int bb = libs[k] + delta[l];
 
            if (!ON_BOARD(bb)
-               || board[bb] != EMPTY
+               || IS_COLOR(board[bb])
                || liberty_of_string(bb, pos))
              continue;
 
@@ -1106,7 +1106,7 @@
   int i, j;
   int k;
 
-  ASSERT1(board[str] != EMPTY, str);
+  ASSERT1(IS_COLOR(board[str]), str);
   ASSERT1(stackp == 0, str);
 
   *lunch = NO_MOVE;
@@ -1401,7 +1401,7 @@
   int num_stones;
   int stones[MAX_BOARD * MAX_BOARD];
   gg_assert(stackp == 0);
-  ASSERT1(board[pos] != EMPTY, pos);
+  ASSERT1(IS_COLOR(board[pos]), pos);
 
   num_stones = findstones(pos, MAX_BOARD * MAX_BOARD, stones);
   for (k = 0; k < num_stones; k++)
@@ -1421,7 +1421,7 @@
 {
   int pos;
   ASSERT_ON_BOARD1(str);
-  ASSERT1(worm[str].color != EMPTY, str);
+  ASSERT1(IS_COLOR(worm[str].color), str);
 
   for (pos = BOARDMIN; pos < BOARDMAX; pos++)
     if (board[pos] == board[str] && is_same_worm(pos, str))
@@ -1661,7 +1661,7 @@
 
   *edge = 0;
 
-  if (board[pos] != EMPTY)
+  if (IS_COLOR(board[pos]))
     origin = find_origin(pos);
   
   cavity_recurse(pos, ml, &border_color, edge, origin);