Extend legality testing to drop moves

[xboard.git] / moves.c

diff --git a/moves.c b/moves.c
index f281aa7..f4f33b2 100644 (file)
--- a/moves.c
+++ b/moves.c
@@ -144,6 +144,7 @@ char pieceToChar[] = {
                         'p', 'n', 'b', 'r', 'q', 'f', 'e', 'a', 'c', 'w', 'm', 
                         'o', 'h', 'i', 'j', 'g', 'd', 'v', 'l', 's', 'u', 'k', 
                         'x' };
+char pieceNickName[EmptySquare];
 
 char PieceToChar(p)
      ChessSquare p;
@@ -167,6 +168,8 @@ ChessSquare CharToPiece(c)
 {
      int i;
      for(i=0; i< (int) EmptySquare; i++)
+          if(pieceNickName[i] == c) return (ChessSquare) i;
+     for(i=0; i< (int) EmptySquare; i++)
           if(pieceToChar[i] == c) return (ChessSquare) i;
      return EmptySquare;
 }
@@ -177,7 +180,7 @@ ChessMove PromoCharToMoveType(whiteOnMove, promoChar)
 {      /* [HGM] made dependent on CharToPiece to alow alternate piece letters */
        ChessSquare piece = CharToPiece(whiteOnMove ? ToUpper(promoChar) : ToLower(promoChar) );
 
-
+       if(promoChar == '=') return whiteOnMove ? WhiteNonPromotion : BlackNonPromotion;
        if(promoChar == NULLCHAR) return NormalMove;
 
        switch(piece) {
@@ -984,7 +987,7 @@ int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
        }
        board[rt][ft] = board[rf][ff];
        board[rf][ff] = EmptySquare;
-    }
+    } else board[rt][ft] = ff; // [HGM] drop
 
     /* For compatibility with ICS wild 9, we scan the board in the
        order a1, a2, a3, ... b1, b2, ..., h8 to find the first king,
@@ -1019,11 +1022,44 @@ int CheckTest(board, flags, rf, ff, rt, ft, enPassant)
        } else {
            board[rt][ft] = captured;
        }
-    }
+    } else board[rt][ft] = EmptySquare; // [HGM] drop
 
     return cl.fking < BOARD_RGHT ? cl.check : 1000; // [HGM] atomic: return 1000 if we have no king
 }
 
+ChessMove LegalDrop(board, flags, piece, rt, ft)
+     Board board;
+     int flags;
+     ChessSquare piece;
+     int rt, ft;
+{   // [HGM] put drop legality testing in separate routine for clarity
+    int n;
+if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
+    if(board[rt][ft] != EmptySquare) return ImpossibleMove; // must drop to empty square
+    n = PieceToNumber(piece);
+    if(gameInfo.holdingsWidth == 0 || (flags & F_WHITE_ON_MOVE ? board[n][BOARD_WIDTH-1] : board[BOARD_HEIGHT-1-n][0]) != piece)
+        return ImpossibleMove; // piece not available
+    if(gameInfo.variant == VariantShogi) { // in Shogi lots of drops are forbidden!
+        if((piece == WhitePawn || piece == WhiteQueen) && rt == BOARD_HEIGHT-1 ||
+           (piece == BlackPawn || piece == BlackQueen) && rt == 0 ||
+            piece == WhiteKnight && rt > BOARD_HEIGHT-3 ||
+            piece == BlackKnight && rt < 2 ) return IllegalMove; // e.g. where dropped piece has no moves
+        if(piece == WhitePawn || piece == BlackPawn) {
+            int r;
+            for(r=1; r<BOARD_HEIGHT-1; r++)
+                if(board[r][ft] == piece) return IllegalMove; // or there already is a Pawn in file
+            // should still test if we mate with this Pawn
+        }
+    } else {
+        if( (piece == WhitePawn || piece == BlackPawn) &&
+            (rt == 0 || rt == BOARD_HEIGHT -1 ) )
+            return IllegalMove; /* no pawn drops on 1st/8th */
+    }
+if(appData.debugMode) fprintf(debugFP, "LegalDrop: %d @ %d,%d)\n", piece, ft, rt);
+    if (!(flags & F_IGNORE_CHECK) &&
+       CheckTest(board, flags, DROP_RANK, piece, rt, ft, FALSE) ) return IllegalMove;
+    return flags & F_WHITE_ON_MOVE ? WhiteDrop : BlackDrop;
+}
 
 extern void LegalityTestCallback P((Board board, int flags, ChessMove kind,
                                    int rf, int ff, int rt, int ft,
@@ -1052,7 +1088,10 @@ ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
      int flags;
      int rf, ff, rt, ft, promoChar;
 {
-    LegalityTestClosure cl; ChessSquare piece = board[rf][ff], *castlingRights = board[CASTLING];
+    LegalityTestClosure cl; ChessSquare piece, *castlingRights = board[CASTLING];
+
+    if(rf == DROP_RANK) return LegalDrop(board, flags, ff, rt, ft);
+    piece = board[rf][ff];
     
     if (appData.debugMode) {
         int i;
@@ -1094,7 +1133,7 @@ ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
                          piece == WhiteKnight && rt > BOARD_HEIGHT-3) /* promotion mandatory */
                              cl.kind = promoChar == '=' ? IllegalMove : WhitePromotionKnight;
                     else /* promotion optional, default is promote */
-                             cl.kind = promoChar == '=' ? NormalMove  : WhitePromotionQueen;
+                             cl.kind = promoChar == '=' ? WhiteNonPromotion : WhitePromotionQueen;
                    
                 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
                                             NormalMove : IllegalMove;
@@ -1104,7 +1143,7 @@ ChessMove LegalityTest(board, flags, rf, ff, rt, ft, promoChar)
                          piece == BlackKnight && rt < 2 ) /* promotion obligatory */
                              cl.kind = promoChar == '=' ? IllegalMove : BlackPromotionKnight;
                     else /* promotion optional, default is promote */
-                             cl.kind = promoChar == '=' ? NormalMove  : BlackPromotionQueen;
+                             cl.kind = promoChar == '=' ? BlackNonPromotion : BlackPromotionQueen;
 
                 } else cl.kind = (promoChar == NULLCHAR || promoChar == 'x' || promoChar == '=') ?
                                             NormalMove : IllegalMove;