Fix for Chessbox bug FS#10363

Chessbox was overflowing GameList[240] causing the board to flip + crash

GameCnt changed to unsigned char which allows the array to roll over
to 0 after 255

define MAX_GAME_CNT 256 and GameList[MAX_GAME_CNT] along with 1 byte GameCnt
should fix this issue

dbg save routine left in for now to help identify any other problems

Added bounds checking to prevent second bug found when loading .pgn files

Change-Id: I2b615c8ecbed4368724412f80ce07346f3cf30a7

1 files changed, 5 insertions, 4 deletions

diff --git a/apps/plugins/chessbox/gnuchess.c b/apps/plugins/chessbox/gnuchess.c
index 5e67df4f39..4b21cd785c 100644
--- a/apps/plugins/chessbox/gnuchess.c
+++ b/apps/plugins/chessbox/gnuchess.c
@@ -103,8 +103,9 @@ short INCscore;
 short HasPawn[2],HasKnight[2],HasBishop[2],HasRook[2],HasQueen[2];
 short ChkFlag[maxdepth],CptrFlag[maxdepth],PawnThreat[maxdepth];
 short Pscore[maxdepth],Tscore[maxdepth],Threat[maxdepth];
-struct GameRec GameList[240];
-short GameCnt,Game50,epsquare,lpost,rcptr,contempt;
+struct GameRec GameList[MAX_GAME_CNT];
+unsigned char GameCnt; /*Bug fix now rolls over instead of overflow*/
+short Game50,epsquare,lpost,rcptr,contempt;
 short MaxSearchDepth,Xscore;
 struct TimeControlRec TimeControl;
 short TCflag,TCmoves,TCminutes,OperatorTime;
@@ -1132,7 +1133,7 @@ static short i,alpha,beta,score,tempb,tempc,tempsf,tempst,xside,rpt;
       if (--TimeControl.moves[side] == 0) SetTimeControl();
     }
   if ((root->flags & draw) && bothsides) quit = true;
-  if (GameCnt > 238) quit = true;
+  if (GameCnt > MAX_GAME_CNT - 2) quit = true;
   player = xside;
   Sdepth = 0;
   return(0);
@@ -2319,7 +2320,7 @@ void NewGame()  {
   xwndw = 90;
   MaxSearchDepth = 29;
   contempt = 0;
-  GameCnt = -1; Game50 = 0;
+  GameCnt = MAX_GAME_CNT - 1; Game50 = 0;
   Zwmtl = Zbmtl = 0;
   Developed[white] = Developed[black] = false;
   castld[white] = castld[black] = false;