From: H.G. Muller <h.g.muller@hccnet.nl>
Date: Sat, 3 Mar 2012 22:32:11 +0000 (+0100)
Subject: Add disambiguation of move with unique piece
X-Git-Url: http://winboard.nl/cgi-bin?p=xboard.git;a=commitdiff_plain;h=a0f11c3028eb6f2911a2abfe2496aed6f33207a5

Add disambiguation of move with unique piece

If no pseudo-legal move of type Xa1 can be found, and only a single
piece of type X is on the board, successfully disambiguate the move
using that piece.
---

diff --git a/moves.c b/moves.c
index f8b7857..1c4fe51 100644
--- a/moves.c
+++ b/moves.c
@@ -1331,14 +1331,23 @@ Disambiguate (Board board, int flags, DisambiguateClosure *closure)
         GenLegal(board, flags|F_IGNORE_CHECK, DisambiguateCallback, (VOIDSTAR) closure, closure->pieceIn);
 	if (closure->count == 0) {
 	    /* No, it's not even that */
+	  if(!appData.testLegality && closure->pieceIn != EmptySquare) {
+	    int f, r; // if there is only a single piece of the requested type on the board, use that
+	    closure->rt = closure->rtIn, closure->ft = closure->ftIn;
+	    for(r=0; r<BOARD_HEIGHT; r++) for(f=BOARD_LEFT; f<BOARD_RGHT; f++)
+		if(board[r][f] == closure->pieceIn) closure->count++, closure->rf = r, closure->ff = f;
+	    if(closure->count > 1) illegal = 0; // ambiguous
+	  }
+	  if(closure->count == 0) {
 	    if (appData.debugMode) { int i, j;
 		for(i=BOARD_HEIGHT-1; i>=0; i--) {
 		    for(j=0; j<BOARD_WIDTH; j++)
-		        fprintf(debugFP, "%3d", (int) board[i][j]);
+			fprintf(debugFP, "%3d", (int) board[i][j]);
 		    fprintf(debugFP, "\n");
 		}
 	    }
 	    return;
+	  }
 	}
     }