Allow null move in analysis and edit-game mode

[xboard.git] / backend.c

diff --git a/backend.c b/backend.c
index f0289bc..a304ca5 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -4861,6 +4861,11 @@ SendMoveToProgram(moveNum, cps)
 {
     char buf[MSG_SIZ];
 
+    if(moveList[moveNum][1] == '@' && moveList[moveNum][0] == '@') {
+       // null move in variant where engine does not understand it (for analysis purposes)
+       SendBoard(cps, moveNum + 1); // send position after move in stead.
+       return;
+    }
     if (cps->useUsermove) {
       SendToProgram("usermove ", cps);
     }
@@ -4901,6 +4906,7 @@ SendMoveToProgram(moveNum, cps)
       } else
       if(BOARD_HEIGHT > 10) { // [HGM] big: convert ranks to double-digit where needed
        if(moveList[moveNum][1] == '@' && (BOARD_HEIGHT < 16 || moveList[moveNum][0] <= 'Z')) { // drop move
+         if(moveList[moveNum][0]== '@') snprintf(buf, MSG_SIZ, "@@@@\n"); else
          snprintf(buf, MSG_SIZ, "%c@%c%d%s", moveList[moveNum][0],
                                              moveList[moveNum][2], moveList[moveNum][3] - '0', moveList[moveNum]+4);
        } else
@@ -5076,6 +5082,7 @@ CoordsToComputerAlgebraic(rf, ff, rt, ft, promoChar, move)
      char move[7];
 {
     if (rf == DROP_RANK) {
+      if(ff == EmptySquare) sprintf(move, "@@@@\n"); else // [HGM] pass
       sprintf(move, "%c@%c%c\n",
                 ToUpper(PieceToChar((ChessSquare) ff)), AAA + ft, ONE + rt);
     } else {
@@ -6527,6 +6534,9 @@ UserMoveEvent(fromX, fromY, toX, toY, promoChar)
     /* [HGM] always test for legality, to get promotion info */
     moveType = LegalityTest(boards[currentMove], PosFlags(currentMove),
                                          fromY, fromX, toY, toX, promoChar);
+
+    if(fromY == DROP_RANK && fromX == EmptySquare && (gameMode == AnalyzeMode || gameMode == EditGame)) moveType = NormalMove;
+
     /* [HGM] but possibly ignore an IllegalMove result */
     if (appData.testLegality) {
        if (moveType == IllegalMove || moveType == ImpossibleMove) {
@@ -6668,6 +6678,9 @@ FinishMove(moveType, fromX, fromY, toX, toY, promoChar)
         // [HGM] book: if program might be playing, let it use book
        bookHit = SendMoveToBookUser(forwardMostMove-1, &first, FALSE);
        first.maybeThinking = TRUE;
+    } else if(fromY == DROP_RANK && fromX == EmptySquare) {
+       if(!first.useSetboard) SendToProgram("undo\n", &first); // kludge to change stm in engines that do not support setboard
+       SendBoard(&first, currentMove+1);
     } else SendMoveToProgram(forwardMostMove-1, &first);
     if (currentMove == cmailOldMove + 1) {
       cmailMoveType[lastLoadGameNumber - 1] = CMAIL_MOVE;
@@ -9006,15 +9019,19 @@ ApplyMove(fromX, fromY, toX, toY, promoChar, board)
       oldEP = (signed char)board[EP_STATUS];
       board[EP_STATUS] = EP_NONE;
 
-      if( board[toY][toX] != EmptySquare )
-           board[EP_STATUS] = EP_CAPTURE;
-
   if (fromY == DROP_RANK) {
        /* must be first */
+        if(fromX == EmptySquare) { // [HGM] pass: empty drop encodes null move; nothing to change.
+           board[EP_STATUS] = EP_CAPTURE; // null move considered irreversible
+           return;
+       }
         piece = board[toY][toX] = (ChessSquare) fromX;
   } else {
       int i;
 
+      if( board[toY][toX] != EmptySquare )
+           board[EP_STATUS] = EP_CAPTURE;
+
       if( board[fromY][fromX] == WhiteLance || board[fromY][fromX] == BlackLance ) {
            if( gameInfo.variant != VariantSuper && gameInfo.variant != VariantShogi )
                board[EP_STATUS] = EP_PAWN_MOVE; // Lance is Pawn-like in most variants
@@ -13559,7 +13576,9 @@ ClockClick(int which)
          if (gameMode == EditPosition || gameMode == IcsExamining) {
            if(!appData.pieceMenu && blackPlaysFirst) EditPositionMenuEvent(ClearBoard, 0, 0);
            SetBlackToPlayEvent();
-         } else if (gameMode == EditGame || shiftKey) {
+         } else if ((gameMode == AnalyzeMode || gameMode == EditGame) && !blackFlag && WhiteOnMove(currentMove)) {
+          UserMoveEvent((int)EmptySquare, DROP_RANK, 0, 0, 0); // [HGM] multi-move: if not out of time, enters null move
+         } else if (shiftKey) {
            AdjustClock(which, -1);
          } else if (gameMode == IcsPlayingWhite ||
                     gameMode == MachinePlaysBlack) {
@@ -13569,7 +13588,9 @@ ClockClick(int which)
          if (gameMode == EditPosition || gameMode == IcsExamining) {
            if(!appData.pieceMenu && !blackPlaysFirst) EditPositionMenuEvent(ClearBoard, 0, 0);
            SetWhiteToPlayEvent();
-         } else if (gameMode == EditGame || shiftKey) {
+         } else if ((gameMode == AnalyzeMode || gameMode == EditGame) && !whiteFlag && !WhiteOnMove(currentMove)) {
+          UserMoveEvent((int)EmptySquare, DROP_RANK, 0, 0, 0); // [HGM] multi-move
+         } else if (shiftKey) {
            AdjustClock(which, -1);
          } else if (gameMode == IcsPlayingBlack ||
                   gameMode == MachinePlaysWhite) {
@@ -13846,6 +13867,16 @@ BackwardInner(target)
     if (gameMode == EditGame || gameMode==AnalyzeMode ||
        gameMode == PlayFromGameFile || gameMode == AnalyzeFile) {
        while (currentMove > target) {
+           if(moveList[currentMove-1][1] == '@' && moveList[currentMove-1][0] == '@') {
+               // null move cannot be undone. Reload program with move history before it.
+               int i;
+               for(i=target; i>backwardMostMove; i--) { // seek back to start or previous null move
+                   if(moveList[i-1][1] == '@' && moveList[i-1][0] == '@') break;
+               }
+               SendBoard(&first, i); 
+               for(currentMove=i; currentMove<target; currentMove++) SendMoveToProgram(currentMove, &first);
+               break;
+           }
            SendToProgram("undo\n", &first);
            currentMove--;
        }