smarter analysis of the boards that XBoard receives from an ICS

I added smarter analysis of the boards that XBoard receves from an ICS,
based on board size and piece types in the position, to recognize cases
where the board does not match the current variant, and switch to an
appropriate variant.

diff --git a/backend.c b/backend.c
index 756641c..e2aa771 100755 (executable)
--- a/backend.c
+++ b/backend.c
@@ -607,7 +607,7 @@ InitBackEnd1()
     ShowThinkingEvent(); // [HGM] thinking: make sure post/nopost state is set according to options
 
     GetTimeMark(&programStartTime);
-    srand(programStartTime.ms); // [HGM] book: makes sure random is unpredictabe to msec level
+    srandom(programStartTime.ms); // [HGM] book: makes sure random is unpredictabe to msec level
 
     ClearProgramStats();
     programStats.ok_to_send = 1;
@@ -3281,7 +3281,13 @@ read_from_ics(isr, closure, data, count, error)
                            * to move the position two files to the right to
                            * create room for them!
                            */
-                          VariantSwitch(boards[currentMove], VariantCrazyhouse); /* temp guess */
+                         VariantClass newVariant;
+                         switch(gameInfo.boardWidth) { // base guess on board width
+                               case 9:  newVariant = VariantShogi; break;
+                               case 10: newVariant = VariantGreat; break;
+                               default: newVariant = VariantCrazyhouse; break;
+                         }
+                          VariantSwitch(boards[currentMove], newVariant); /* temp guess */
                          /* Get a move list just to see the header, which
                             will tell us whether this is really bug or zh */
                          if (ics_getting_history == H_FALSE) {
@@ -3391,6 +3397,7 @@ ParseBoard12(string)
     char promoChar;
     int ranks=1, files=0; /* [HGM] ICS80: allow variable board size */
     char *bookHit = NULL; // [HGM] book
+    Boolean weird = FALSE;
 
     fromX = fromY = toX = toY = -1;
     
@@ -3406,6 +3413,7 @@ ParseBoard12(string)
         while(i < 199 && (string[i] != ' ' || string[i+2] != ' ')) {
            if(string[i] == ' ') { ranks++; files = 0; }
             else files++;
+           if(!strchr(" -pnbrqkPNBRQK" , string[i])) weird = TRUE; // test for fairies
            i++;
        }
        for(j = 0; j <i; j++) board_chars[j] = string[j];
@@ -3418,6 +3426,26 @@ ParseBoard12(string)
               &white_stren, &black_stren, &white_time, &black_time,
               &moveNum, str, elapsed_time, move_str, &ics_flip,
               &ticking);
+fprintf(debugFP, "old: %dx%d   new: %dx%d weird=%d variant=%d\n",gameInfo.boardHeight,gameInfo.boardWidth,ranks,files,weird,gameInfo.variant);fflush(debugFP);
+   if (gameInfo.boardHeight != ranks || gameInfo.boardWidth != files || 
+                                       weird && (int)gameInfo.variant <= (int)VariantShogi) {
+     /* [HGM] We seem to switch variant during a game!
+      * Try to guess new variant from board size
+      */
+         VariantClass newVariant = VariantFairy; // if 8x8, but fairies present
+         if(ranks == 8 && files == 10) newVariant = VariantCapablanca; else
+         if(ranks == 10 && files == 9) newVariant = VariantXiangqi; else
+         if(ranks == 8 && files == 12) newVariant = VariantCourier; else
+         if(ranks == 9 && files == 9)  newVariant = VariantShogi;
+          VariantSwitch(boards[currentMove], newVariant); /* temp guess */
+         /* Get a move list just to see the header, which
+            will tell us whether this is really bug or zh */
+         if (ics_getting_history == H_FALSE) {
+           ics_getting_history = H_REQUESTED;
+           sprintf(str, "%smoves %d\n", ics_prefix, gamenum);
+           SendToICS(str);
+         }
+    }
 
     if (n < 21) {
         snprintf(str, sizeof(str), _("Failed to parse board string:\n\"%s\""), string);