MBCBoard.mm   [plain text]


/*
	File:		MBCBoard.mm
	Contains:	Implementation of fundamental board and move classes
	Copyright:	 2002-2011 by Apple Inc., all rights reserved.

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	The Apple Software is provided by Apple on an "AS IS" basis.  APPLE
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*/
#import "MBCBoard.h"
#import "MBCEngineCommands.h"
#import "MBCMoveGenerator.h"
#import "MBCPlayer.h"
#import "MBCDocument.h"

#import <string.h>
#include <ctype.h>

NSString *  gVariantName[] = {
	@"normal", @"crazyhouse", @"suicide", @"losers", nil
};

const char  gVariantChar[]	= "nzsl";

const MBCSide gHumanSide[]  = {
    kBothSides, kWhiteSide, kBlackSide, kNeitherSide, kBothSides
};

const MBCSide gEngineSide[] = {
    kNeitherSide, kBlackSide, kWhiteSide, kBothSides, kNeitherSide
};

MBCPiece Captured(MBCPiece victim)
{
	victim = Opposite(victim & ~kPieceMoved);
	if (Promoted(victim))	// Captured promoted pieces revert to pawns
		return Matching(victim, PAWN);
	else
		return victim;
}

static const char * sPieceChar = " KQBNRP";

@implementation MBCMove

- (id) initWithCommand:(MBCMoveCode)command;
{
	fCommand	=	command;
	fFromSquare	=	kInvalidSquare;
	fToSquare	=	kInvalidSquare;
	fPiece		=	EMPTY;
	fPromotion	= 	EMPTY;
	fVictim		= 	EMPTY;
	fCastling	=	kUnknownCastle;
	fEnPassant	= 	NO;
	fAnimate	=	YES;
	
	return self;
}

+ (id) newWithCommand:(MBCMoveCode)command
{
	return [[MBCMove alloc] initWithCommand:command];
}

+ (id) moveWithCommand:(MBCMoveCode)command
{
	return [[MBCMove newWithCommand:command] autorelease];
}

- (id) initFromCompactMove:(MBCCompactMove)move
{
	[self initWithCommand:MBCMoveCode(move >> 24)];
	
	switch (fCommand) {
	case kCmdMove:	
	case kCmdPMove:
		fFromSquare	= (move >> 16) & 0xFF;
		fToSquare	= (move >> 8)  & 0xFF;
		fPromotion	= move & 0xFF;
		break;
	case kCmdDrop:
	case kCmdPDrop:
		fToSquare	= (move >> 8)  & 0xFF;
		fPiece		= move & 0xFF;
		break;
	default:
		break;
	}

	return self;
}

+ (id) newFromCompactMove:(MBCCompactMove)move
{
	return [[MBCMove alloc] initFromCompactMove:move];
}

+ (id) moveFromCompactMove:(MBCCompactMove)move
{
	return [[MBCMove newFromCompactMove:move] autorelease];
}

- (id) initFromEngineMove:(NSString *)engineMove
{
	const char * piece	= " KQBNRP  kqbnrp ";
	const char * move	= [engineMove UTF8String];

	if (move[1] == '@') {
		[self initWithCommand:kCmdDrop];
		fPiece		= static_cast<MBCPiece>(strchr(piece, move[0])-piece);
		fToSquare	= Square(move+2);
	} else {
		[self initWithCommand:kCmdMove];
		fFromSquare	= Square(move);
		fToSquare	= Square(move+2);
		if (move[4])
			fPromotion	= static_cast<MBCPiece>(strchr(piece, move[4])-piece);
	}
	
	return self;
}

+ (id) newFromEngineMove:(NSString *)engineMove
{
	return [[MBCMove alloc] initFromEngineMove:engineMove];
}

+ (id) moveFromEngineMove:(NSString *)engineMove
{
	return [[MBCMove newFromEngineMove:engineMove] autorelease];
}

+ (BOOL)compactMoveIsWin:(MBCCompactMove)move
{
    switch (move >> 24) {
    case kCmdWhiteWins:
    case kCmdBlackWins:
        return YES;
    default:
        return NO;
    }
}

NSString * sPieceLetters[] = {
	@"",
	@"king_letter",
	@"queen_letter",
	@"bishop_letter",
	@"knight_letter",
	@"rook_letter",
	@"pawn_letter"
};

- (NSString *) pieceLetter:(MBCPiece)piece forDrop:(BOOL)drop
{
	piece = Piece(piece);
	if (!drop && piece==PAWN)
		return @" ";
	else
		return NSLocalizedString(sPieceLetters[piece], 
								 "Piece Letter");
}

- (NSString *) localizedText
{
    NSString * origin       = [self origin];
    NSString * operation    = [self operation];
    NSString * destination  = [self destinationForTitle:YES];
    NSString * check        = [self check];
    NSString * text;
    if ([origin length] || [destination length])
        text = [NSString localizedStringWithFormat:NSLocalizedString(@"title_move_fmt", "%@%@%@"),
                origin, operation, destination];
    else 
        text = operation;
    if ([check length])
        text = [NSString localizedStringWithFormat:NSLocalizedString(@"title_check_fmt", @"%@%@"),
                text, check];
    
    return text;
}

- (NSString *) origin
{
	switch (fCommand) {
	case kCmdMove:
	case kCmdPMove:
		if (fCastling != kNoCastle)
			return @"";
		else 
			return [NSString localizedStringWithFormat:NSLocalizedString(@"move_origin_fmt", @"%@%c%c"),
					[self pieceLetter:fPiece forDrop:NO],
					Col(fFromSquare), Row(fFromSquare)+'0'];
	case kCmdDrop:
	case kCmdPDrop:
		return [NSString localizedStringWithFormat:NSLocalizedString(@"drop_origin_fmt", @"%@"),
				[self pieceLetter:fPiece forDrop:YES]];
	default:
		return @"";
	}
}

- (NSString *) operation
{
	UniChar op = fVictim ? 0x00D7 : '-';
	switch (fCommand) {
	case kCmdMove:
	case kCmdPMove:
		switch (fCastling) {
		case kCastleQueenside:
			return @"0 - 0 - 0";
		case kCastleKingside:
			return @"0 - 0";
		default:
			break;
		}
		break;
	case kCmdDrop:
	case kCmdPDrop:
		op = '@';
		break;
	default:
		op = ' ';
		break;
	}
	return [NSString localizedStringWithFormat:NSLocalizedString(@"operation_fmt", @"%C"), op];
}

- (NSString *) destinationForTitle:(BOOL)forTitle
{
    NSString * check = [self check];
    NSString * text;
	if (fCastling != kNoCastle && fCastling != kUnknownCastle)
		return check;
	else if (fPromotion)
		text = [NSString localizedStringWithFormat:NSLocalizedString(@"promo_dest_fmt", @"%c%c=@%"),
                    Col(fToSquare), Row(fToSquare)+'0', [self pieceLetter:fPromotion forDrop:NO]];
	else
		text = [NSString localizedStringWithFormat:NSLocalizedString(@"move_dest_fmt", @"%c%c"),
                    Col(fToSquare), Row(fToSquare)+'0']; 
    if ([check length])
        return [NSString localizedStringWithFormat:NSLocalizedString(@"dest_check_fmt", @"%@ %@"),
                text, check];
    else 
        return text;
}

- (NSString *) destination
{
    return [self destinationForTitle:NO];
}

- (NSString *) check
{
    if (fCheckMate)
        return NSLocalizedString(@"move_is_checkmate", @"");
    else if (fCheck)
        return NSLocalizedString(@"move_is_check", @"+");
    else
        return @"";
}

- (NSString *) engineMove
{
	const char * piece	= " KQBNRP  kqbnrp ";

#define SQUARETOCOORD(sq) 	Col(sq), Row(sq)+'0'

	switch (fCommand) {
	case kCmdMove:
		if (fPromotion) 
			return [NSString stringWithFormat:@"%c%c%c%c%c\n", 
							 SQUARETOCOORD(fFromSquare),
							 SQUARETOCOORD(fToSquare),
							 piece[fPromotion&15]];
		else
			return [NSString stringWithFormat:@"%c%c%c%c\n", 
							 SQUARETOCOORD(fFromSquare),
							 SQUARETOCOORD(fToSquare)];
	case kCmdDrop:
		return [NSString stringWithFormat:@"%c@%c%c\n", 
						 piece[fPiece&15],
						 SQUARETOCOORD(fToSquare)];
		break;
	default:
		return nil;
	}	
}

@end

bool MBCPieces::NoPieces(MBCPieceCode color)
{
    color = (MBCPieceCode)Opposite(Color(color));
    
    return fInHand[color+QUEEN]  == 1
        && fInHand[color+BISHOP] == 2
        && fInHand[color+KNIGHT] == 2
        && fInHand[color+ROOK]   == 2
        && fInHand[color+PAWN]   == 8;
}

@implementation MBCBoard

- (id)init
{
    if (self = [super init])
        fObservers = [[NSMutableArray alloc] init];
    
    return self;
}

- (void)removeChessObservers
{
    NSNotificationCenter * notificationCenter = [NSNotificationCenter defaultCenter];
    [fObservers enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
        [notificationCenter removeObserver:obj];
    }];
    [fObservers removeAllObjects];
}

- (void)dealloc
{
    [self removeChessObservers];
    [fObservers release];
    [fMoves release];
    [super dealloc];
}

- (void)setDocument:(id)doc
{
    fDocument   = doc;
	fMoves      = nil;

	[self resetWithVariant:[doc variant]];
    
    [self removeChessObservers];
    [fObservers addObject:
     [[NSNotificationCenter defaultCenter]
        addObserverForName:MBCGameLoadNotification object:doc
        queue:[NSOperationQueue mainQueue] usingBlock:^(NSNotification *note) {
            NSDictionary * dict    = [note userInfo];
            NSString *     fen     = [dict objectForKey:@"Position"];
            NSString *     holding = [dict objectForKey:@"Holding"];
            NSString *     moves   = [dict objectForKey:@"Moves"];
            fVariant               = [doc variant];

            if (fen || moves)
                [self setFen:fen holding:holding moves:moves];
        }]];
}

- (void) resetWithVariant:(MBCVariant)variant
{
	memset(fCurPos.fBoard, EMPTY, 64);
	memset(fCurPos.fInHand, 0, 16);

	/* White pieces */
	fCurPos.fBoard[Square('a',1)] = White(ROOK);
	fCurPos.fBoard[Square('b',1)] = White(KNIGHT);
	fCurPos.fBoard[Square('c',1)] = White(BISHOP);
	fCurPos.fBoard[Square('d',1)] = White(QUEEN);
	fCurPos.fBoard[Square('e',1)] = White(KING);
	fCurPos.fBoard[Square('f',1)] = White(BISHOP);
	fCurPos.fBoard[Square('g',1)] = White(KNIGHT);
	fCurPos.fBoard[Square('h',1)] = White(ROOK);
	fCurPos.fBoard[Square('a',2)] = White(PAWN);
	fCurPos.fBoard[Square('b',2)] = White(PAWN);
	fCurPos.fBoard[Square('c',2)] = White(PAWN);
	fCurPos.fBoard[Square('d',2)] = White(PAWN);
	fCurPos.fBoard[Square('e',2)] = White(PAWN);
	fCurPos.fBoard[Square('f',2)] = White(PAWN);
	fCurPos.fBoard[Square('g',2)] = White(PAWN);
	fCurPos.fBoard[Square('h',2)] = White(PAWN);

	/* Black pieces */
	fCurPos.fBoard[Square('a',7)] = Black(PAWN);
	fCurPos.fBoard[Square('b',7)] = Black(PAWN);
	fCurPos.fBoard[Square('c',7)] = Black(PAWN);
	fCurPos.fBoard[Square('d',7)] = Black(PAWN);
	fCurPos.fBoard[Square('e',7)] = Black(PAWN);
	fCurPos.fBoard[Square('f',7)] = Black(PAWN);
	fCurPos.fBoard[Square('g',7)] = Black(PAWN);
	fCurPos.fBoard[Square('h',7)] = Black(PAWN);
	fCurPos.fBoard[Square('a',8)] = Black(ROOK);
	fCurPos.fBoard[Square('b',8)] = Black(KNIGHT);
	fCurPos.fBoard[Square('c',8)] = Black(BISHOP);
	fCurPos.fBoard[Square('d',8)] = Black(QUEEN);
	fCurPos.fBoard[Square('e',8)] = Black(KING);
	fCurPos.fBoard[Square('f',8)] = Black(BISHOP);
	fCurPos.fBoard[Square('g',8)] = Black(KNIGHT);
	fCurPos.fBoard[Square('h',8)] = Black(ROOK);

	fPrvPos		= fCurPos;
	fVariant	= variant;
	fMoveClock	= 0;

	[fMoves release];
	fMoves	= [[NSMutableArray alloc] init];

	fPromotion[0] = QUEEN;
	fPromotion[1] = QUEEN;
}

- (void) startGame:(MBCVariant)variant
{
	[self resetWithVariant:variant];
}

- (MBCPiece) curContents:(MBCSquare)square
{
	return fCurPos.fBoard[square];
}

- (MBCPiece) oldContents:(MBCSquare)square
{
	return fPrvPos.fBoard[square];
}

- (int) curInHand:(MBCPiece)piece
{
	return fCurPos.fInHand[piece];
}

- (int) oldInHand:(MBCPiece)piece
{
	return fPrvPos.fInHand[piece];
}

//
// After every move, pieces on the board and in hand have to balance out
//
- (void) consistencyCheck
{
	char	inventory[8];

	memset(inventory, 0, 8);
	
	inventory[PAWN]		= 16;
	inventory[ROOK]		=  4;
	inventory[KNIGHT]	=  4;
	inventory[BISHOP]	=  4;
	inventory[QUEEN]	=  2;
	inventory[KING]		=  2;

	for (MBCPiece * p = fCurPos.fBoard; p < fCurPos.fBoard+64; ++p) {
		MBCPiece piece = *p;
		--inventory[Promoted(piece) ? PAWN : Piece(piece)];
	}
	for (int i = 1; i < 8; ++i) {
		inventory[i] -= fCurPos.fInHand[i]+fCurPos.fInHand[i|kBlackPiece];
		if (inventory[i]) 
            MBCAbort([NSString localizedStringWithFormat:@"Board consistency check: %d %d\n", i, inventory[i]],
                     fDocument);
	}
#if 0
	MBCMoveGenerator	logMoves([MBCDebugMoveBuilder debugMoveBuilder], 
								 fVariant, 0);
	logMoves.Generate(!([fMoves count] & 1), fCurPos);
	if (logMoves.InCheck(!([fMoves count] & 1), fCurPos)) 
		NSLog(@"Check!");
#endif
}

- (void) makeMove:(MBCMove *)move
{	
	//
	// Ignore everything except moves & drops
	//
	if (move->fCommand != kCmdMove && move->fCommand != kCmdDrop)
		return;

	//
	// Make the move on the board
	//
	MBCSquare	toSquare	= move->fToSquare;
	MBCSquare	fromSquare	= move->fFromSquare;
	MBCPiece * 	board		= fCurPos.fBoard;
	char *		inHand		= fCurPos.fInHand;
	MBCPiece 	piece 		= move->fPromotion;

	if (move->fCommand == kCmdMove) {
		move->fPiece = board[fromSquare];
		[self tryCastling:move];
		[self tryPromotion:move];
		if (!piece) { 
			//
			// Not a pawn promotion, piece stays the same
			//
			piece = move->fPiece;
		} else { 
			//
			// Pawn promotion
			//
			move->fPromotion = 
				Piece(piece) | Color(move->fPiece) | kPromoted;
			piece = move->fPromotion | kPieceMoved;
		}
		if (MBCPiece victim = board[toSquare]) {
			//
			// Record captured piece
			//
			move->fVictim = victim;
			++inHand[Captured(victim)];
		} else if (Piece(piece) == PAWN && Col(fromSquare) != Col(toSquare)) {
			//
			// En passant capture
			//
			MBCSquare victimSquare  = Square(Col(toSquare), Row(fromSquare));
			MBCPiece  victim		= board[victimSquare];
			move->fVictim 			= victim;
			++inHand[Captured(victim)];
			board[victimSquare] 	= EMPTY;
			move->fEnPassant		= YES;
		}
		if (move->fVictim || Piece(move->fPiece) == PAWN)
			fMoveClock	= 0;
		else 
			++fMoveClock;
		board[fromSquare] = EMPTY;
		unsigned row = Row(toSquare);
		switch (move->fCastling) {
		case kUnknownCastle:
		case kNoCastle:
			break;
		case kCastleQueenside:
			board[Square('d', row)] = board[Square('a', row)] | kPieceMoved;
			board[Square('a', row)] = EMPTY;
			break;
		case kCastleKingside:
			board[Square('f', row)] = board[Square('h', row)] | kPieceMoved;
			board[Square('h', row)] = EMPTY;
			break;
		}
		piece			   |= kPieceMoved;
		if (!move->fVictim && Piece(piece) == PAWN && 
			abs(Row(fromSquare)-Row(toSquare))==2
		)
			fCurPos.fEnPassant	= Square(Col(fromSquare), 
										 (Row(fromSquare)+Row(toSquare))/2);
		else
			fCurPos.fEnPassant	= kInvalidSquare;
	} else { 
		//
		// Drop, deplete in hand pieces. A dropped piece is not considered
		// to have moved yet.
		//
		piece	= move->fPiece;
		if (--inHand[piece] < 0)
            MBCAbort([NSString localizedStringWithFormat:@"Dropping non-existent %c", 
                      sPieceChar[Piece(move->fPiece)]], 
                     fDocument);
    
	}
	board[toSquare] = piece;

	//
	// Record the move made in undo buffer
	//
	[fMoves addObject:move];
    
    //
    // Is the move a check?
    //
    if (fVariant != kVarSuicide) {
        MBCMoveGenerator	checkChecker(nil, fVariant, 0);
        if ((move->fCheck = checkChecker.InCheck(!([fMoves count] & 1), fCurPos)))
            move->fCheckMate = checkChecker.InCheckMate(!([fMoves count] & 1), fCurPos);
    }
    
	[self consistencyCheck];
}

- (MBCCastling) tryCastling:(MBCMove *)move
{
	move->fCastling			= kNoCastle;

	MBCSquare   fromSquare 	= move->fFromSquare;
	MBCPiece * 	board		= fCurPos.fBoard;
	MBCPiece	king 		= move->fPiece;

	if (Piece(king) != KING || king & kPieceMoved) 
		return kNoCastle;
	MBCPieceCode 	kingColor = Color(king);
	unsigned 		row = Row(move->fToSquare);
	if (Row(fromSquare) != row)
		return kNoCastle;
		
	//
	// These comparisons will fail if the rook has kPieceMoved set, which
	// they should.
	//
	switch (Col(move->fToSquare)) {
	case 'c':	// Queenside castle
		if (board[Square('a', row)] != Matching(kingColor, ROOK)
		 || board[Square('b', row)] != EMPTY
		 || board[Square('c', row)] != EMPTY
		 || board[Square('d', row)] != EMPTY
		)
			return kNoCastle;
		else
			return move->fCastling = kCastleQueenside;
	case 'g':	// Kingside castle
		if (board[Square('h', row)] != Matching(kingColor, ROOK)
		 || board[Square('g', row)] != EMPTY
		 || board[Square('f', row)] != EMPTY
		)
			return kNoCastle;
		else
			return move->fCastling = kCastleKingside;
	default:
		return kNoCastle;
	}
}

- (void)tryPromotion:(MBCMove *)move
{
	if (move->fCommand == kCmdMove 
	  && Piece(fCurPos.fBoard[move->fFromSquare]) == PAWN
    )
		//
		// Possibly a promotion where we need to fill in the piece
		//
		switch (Row(move->fToSquare)) {
		case 1:
			//
			// Black promotion
			//
			if (!move->fPromotion)
				move->fPromotion = fPromotion[0];
			break;
		case 8:
			//
			// White promotion
			//
			if (!move->fPromotion)
				move->fPromotion = fPromotion[1]; 
			break;
		default:
			move->fPromotion = EMPTY;
			break;
		}
}

- (MBCSide)sideOfMove:(MBCMove *)move
{
    switch (move->fCommand) {
    case kCmdWhiteWins:
        return kWhiteSide;
    case kCmdBlackWins:
        return kBlackSide;
    case kCmdDraw:
        return ([fMoves count] & 1) ? kWhiteSide : kBlackSide;
    default:
        return Color(move->fPiece)==kWhitePiece ? kWhiteSide : kBlackSide;
    }
}

- (BOOL) reachFromCol:(char)fromCol row:(unsigned)fromRow
			 deltaCol:(int)colDelta row:(int)rowDelta
				steps:(int)steps
{
	if (steps < 0)
		steps = -steps;
	while (--steps > 0) 
		if (fCurPos.fBoard[Square(fromCol += colDelta, fromRow += rowDelta)])
			return NO; // Occupied square in between

	return YES;
}

- (BOOL) reachDiagonalFromCol:(char)fromCol row:(unsigned)fromRow
						toCol:(char)toCol row:(unsigned)toRow
{
	int colDiff	= toCol - fromCol;
	int rowDiff	= (int)toRow - (int)fromRow;

	if (colDiff != rowDiff && colDiff != -rowDiff)
		return NO;	// Not on same diagonal

	return [self reachFromCol:fromCol row:fromRow 
				 deltaCol:(colDiff<0 ? -1 : 1) row:(rowDiff<0 ? -1 : 1)
				 steps:colDiff];
}

- (BOOL) reachStraightFromCol:(char)fromCol row:(unsigned)fromRow
						toCol:(char)toCol row:(unsigned)toRow
{
	if (fromRow==toRow)
		return [self reachFromCol:fromCol row:fromRow 
					 deltaCol:(toCol<fromCol ? -1 : 1) row:0 
					 steps:toCol-fromCol];
	else if (fromCol==toCol)
		return [self reachFromCol:fromCol row:fromRow 
					 deltaCol:0 row:(toRow<fromRow ? -1 : 1)
					 steps:toRow-fromRow];
	else
		return NO;
}

- (MBCUnique) disambiguateMove:(MBCMove *)move
{
	MBCSquare 	from	= move->fFromSquare;
	unsigned	fromRow	= Row(from);
	char		fromCol	= Col(from);
	MBCSquare 	to		= move->fToSquare;
	unsigned	toRow	= Row(to);
	char		toCol	= Col(to);
	MBCPiece 	piece	= fCurPos.fBoard[from];
	MBCUnique	unique	= 0;

	for (char col = 'a'; col < 'i'; ++col)
		for (unsigned row = 1; row<9; ++row) {
			if (col == fromCol && row == fromRow)
				continue;	// Same as from square
			if (col == toCol && row == toRow)
				continue;	// Same as to square
			if ((fCurPos.fBoard[Square(col, row)] ^ piece) & 15) 
				continue;	// Not a matching piece
			switch (Piece(piece)) {
			case PAWN: 
				//
				// The only column ambiguities can exist with captures
				//
				if (fromRow == row && toCol-fromCol == col-toCol)
					break;	
				continue;
			case KING: // Multiple kings? Only in suicide
				if (col>=toCol-1 && col<=toCol+1 && row>=toRow-1 && row<=toRow+1)
					break;
				continue;
			case KNIGHT: 
				if (col == toCol-1 || col == toCol+1) {
					if (row == toRow-2 || row == toRow+2)
						break;
				} else if (col == toCol-2 || col == toCol+2) {
					if (row == toRow-1 || row == toRow+1)
						break;
				}
				continue;
			case BISHOP:
				if ([self reachDiagonalFromCol:col row:row toCol:toCol row:toRow])
					break;
				continue;
			case QUEEN:
				if ([self reachDiagonalFromCol:col row:row toCol:toCol row:toRow])
					break;
				// Fall through
			case ROOK:
				if ([self reachStraightFromCol:col row:row toCol:toCol row:toRow])
					break;
				continue;
			default:
				continue;
			}
			unique	|= kMatchingPieceExists;
			if (row == fromRow)
				unique	|= kMatchingPieceOnSameRow;
			if (col == fromCol)
				unique	|= kMatchingPieceOnSameCol;
		}	
	return unique;
}

- (bool) undoMoves:(int)numMoves
{
	if ((int)[fMoves count]<numMoves)
		return false;

	if (fMoveClock < numMoves)
		fMoveClock = 0;
	else
		fMoveClock -= numMoves;

	while (numMoves-- > 0) {
		MBCMove *  	move 		= [fMoves lastObject];
		MBCPiece * 	board		= fCurPos.fBoard;
		char *		inHand		= fCurPos.fInHand;
	
		if (move->fCommand == kCmdMove) {
			board[move->fFromSquare] = move->fPiece;
			unsigned row = Row(move->fToSquare);
			switch (move->fCastling) {
			case kUnknownCastle:	
			case kNoCastle:	
				break;
			case kCastleQueenside:
				board[Square('a', row)] = 
					board[Square('d', row)] & ~kPieceMoved;
				board[Square('d', row)] = EMPTY;
				break;
			case kCastleKingside:
				board[Square('h', row)] = 
					board[Square('f', row)] & ~kPieceMoved;
				board[Square('f', row)] = EMPTY;
				break;
			}
		} else 
			++inHand[move->fPiece];
		board[move->fToSquare] = EMPTY;
		if (MBCPiece victim = move->fVictim) {
			MBCSquare victimSquare =
				move->fEnPassant 
				? Square(Col(move->fToSquare), Row(move->fFromSquare))
				: move->fToSquare;
			board[victimSquare] = victim;
			--inHand[Captured(victim)];
		}

		[fMoves removeLastObject];

		[self consistencyCheck];
	}
	fPrvPos = fCurPos;

	return true;
}

- (void) commitMove
{
	fPrvPos = fCurPos;
}

- (NSString *) fen
{
	char 	pos[128];
	char * 	p	= pos;

	*p++ = ' ';
	for (MBCSquare rank = 64; rank; rank -= 8) {
		for (MBCSquare square = rank-8; square < rank; ++square) 
			if (MBCPiece piece = fCurPos.fBoard[square])
				*p++ = " KQBNRP  kqbnrp "[What(piece)];
			else if (isdigit(p[-1]))
				++p[-1];
			else
				*p++ = '1';
		if (rank > 8)
			*p++ = '/';
	}
	*p++ = ' ';
	*p++ = ([fMoves count]&1) ? 'b' : 'w';
	*p++ = ' ';
	if (fCurPos.fBoard[Square('e', 1)] == White(KING)) {
		if (fCurPos.fBoard[Square('h', 1)] == White(ROOK))
			*p++ = 'K';
		if (fCurPos.fBoard[Square('a', 1)] == White(ROOK))
			*p++ = 'Q';
	}
	if (fCurPos.fBoard[Square('e', 8)] == Black(KING)) {
		if (fCurPos.fBoard[Square('h', 8)] == Black(ROOK))
			*p++ = 'k';
		if (fCurPos.fBoard[Square('a', 8)] == Black(ROOK))
			*p++ = 'q';
	}
	if (p[-1] == ' ')
		*p++ = '-';
	*p++ = ' ';
	*p++ = '-';
	if ([fMoves count]) {
		MBCMove *  move = [fMoves lastObject];
		if ((move->fPiece & (7|kPieceMoved)) == PAWN
			&& (Row(move->fToSquare) & 6) == 4
		) {
		    p[-1] = Col(move->fToSquare);
			*p++  = Row(move->fToSquare) == 4 ? '3' : '6';
		}
	}
	snprintf(p, 32, " %d %lu", fMoveClock, ([fMoves count]/2)+1);

	return [NSString stringWithUTF8String:pos+1];
}

- (NSString *) holding
{
	char 	pos[128];
	char * 	p	= pos;

	*p++ = '[';
	for (MBCPiece piece = White(KING); piece <= Black(PAWN); ++piece) {
		for (int count = fCurPos.fInHand[piece]; count-- > 0; )
			*p++ = " KQBNRP "[Piece(piece)];
		if (piece == 8) {
			strcpy(p, "] [");
			p += 3;
		}
	}
	strcpy(p, "]");

	return [NSString stringWithUTF8String:pos];
}

- (NSString *)moves
{	
	NSMutableString * 	moves 		= [NSMutableString stringWithCapacity:200];
	int 				numMoves 	= [fMoves count];

	for (int m = 0; m<numMoves; ++m) {
		MBCMove *  move = [fMoves objectAtIndex:m];
		[moves appendString:[move engineMove]];
	}
	return moves;
}

- (void) setFen:(NSString *)fen holding:(NSString *)holding 
	moves:(NSString *)moves
{
	if (moves) {
		//
		// We prefer to restore the game by replaying the moves
		//
		[self resetWithVariant:fVariant];
		NSArray * 		m = [moves componentsSeparatedByString:@"\n"];
		NSEnumerator *	e = [m objectEnumerator];
		while (NSString * move = [e nextObject]) 
			if ([move length])
				[self makeMove:[MBCMove moveFromEngineMove:move]];
		if (![fen isEqual:[self fen]]) 
			NSLog(@"FEN Mismatch, Expected: <%@> Got <%@>\n",
				  fen, [self fen]);
	} else {
		const char * s = [fen UTF8String];
		MBCPiece *   b = fCurPos.fBoard+56;
		MBCPiece	 p;

		memset(fCurPos.fBoard, 0, 64);
		while (isspace(*s))
			++s;
		do {
			switch (*s++) {
			case 'K':
				p = White(KING) | kPieceMoved;
				break;
			case 'Q':
				p = White(QUEEN);
				break;
			case 'B':
				p = White(BISHOP);
				break;
			case 'N':
				p = White(KNIGHT);
				break;
			case 'R':
				p = White(ROOK) | kPieceMoved;
				break;
			case 'P':
				p = White(PAWN) | kPieceMoved;
				break;
			case 'k':
				p = Black(KING) | kPieceMoved;
				break;
			case 'q':
				p = Black(QUEEN);
				break;
			case 'b':
				p = Black(BISHOP);
				break;
			case 'n':
				p = Black(KNIGHT);
				break;
			case 'r':
				p = Black(ROOK) | kPieceMoved;
				break;
			case 'p':
				p = Black(PAWN) | kPieceMoved;
				break;
			case '8':
			case '7':
			case '6':
			case '5':
			case '4':
			case '3':
			case '2':
			case '1':
				p =  EMPTY;
				b += s[-1]-'0';
				if (!((b-fCurPos.fBoard) & 7))
					b -= 16; // Start previous rank
				break;
			case '/':
			default:
				p = EMPTY;
				break;
			}
			if (p) {
				*b++ = p;
				if (!((b-fCurPos.fBoard) & 7))
					b -= 16; // Start previous rank
			}
		} while (b >= fCurPos.fBoard);

		while (isspace(*s))
			++s;

		if (*s++ == 'b')	
			[fMoves addObject:[MBCMove moveWithCommand:kCmdNull]];
		
		while (isspace(*s))
			++s;
		
		while (!isspace(*s))
			switch (*s++) {
			case 'K':
				fCurPos.fBoard[4] &= ~kPieceMoved;
				fCurPos.fBoard[7] &= ~kPieceMoved;
				break;
			case 'Q':
				fCurPos.fBoard[4] &= ~kPieceMoved;
				fCurPos.fBoard[0] &= ~kPieceMoved;
				break;
			case 'k':
				fCurPos.fBoard[60] &= ~kPieceMoved;
				fCurPos.fBoard[63] &= ~kPieceMoved;
				break;
			case 'q':
				fCurPos.fBoard[60] &= ~kPieceMoved;
				fCurPos.fBoard[56] &= ~kPieceMoved;
				break;
			}

		while (isspace(*s))
			++s;

		if (*s == '-')
			fCurPos.fBoard[Square(*s, s[1]-'0')] &= ~kPieceMoved;
		s += 2;

		while (isspace(*s))
			++s;

		fMoveClock = 0;
		while (isdigit(*s))
			fMoveClock = 10*fMoveClock + *s++ - '0';

		memset(fCurPos.fInHand, 0, 16);

		s = [holding UTF8String];

		s = strchr(s, '[');
		if (!s)
			return;

		do {
			switch (*++s) {
			case 'Q':
				p	= White(QUEEN);
				break;
			case 'B':
				p	= White(BISHOP);
				break;
			case 'N':
				p	= White(KNIGHT);
				break;
			case 'R':
				p 	= White(ROOK);
				break;
			case 'P':
				p	= White(PAWN);
				break;
			default:
				p	= 0;
				break;
			}
			if (p)
				++fCurPos.fInHand[p];
		} while (p);

		s = strchr(s, '[');
		if (!s)
			return;
		
		do {
			switch (*++s) {
			case 'Q':
				p	= Black(QUEEN);
				break;
			case 'B':
				p	= Black(BISHOP);
				break;
			case 'N':
				p	= Black(KNIGHT);
				break;
			case 'R':
				p	= Black(ROOK);
				break;
			case 'P':
				p	= Black(PAWN);
				break;
			default:
				p 	= 0;
				break;
			}
			if (p)
				++fCurPos.fInHand[p];
		} while (p);
	}
	fPrvPos = fCurPos;
}

- (BOOL) saveMovesTo:(FILE *)f
{
	NSArray * existingMoves = [fMoves copy];
	int moves = [fMoves count];
	
	//
	// Reset board so we can disambiguate moves
	//
	[self undoMoves:moves];

	//
	// Now retrace the moves
	//
	for (int m = 0; m<moves; ++m) {
		if (!(m&1)) {
			if (!(m%10))
				fputc('\n', f);
			fprintf(f, "%d. ", (m / 2)+1);
		}
		MBCMove *  move = [existingMoves objectAtIndex:m];

		if (move->fCommand == kCmdDrop) { // Drop, never ambiguous
			fprintf(f, "%c@%c%d ", sPieceChar[Piece(move->fPiece)], 
					Col(move->fToSquare), Row(move->fToSquare));
		} else { // Move, may be ambiguous
			MBCPiece  p = Piece(fCurPos.fBoard[move->fFromSquare]);

			if (p==PAWN) { // Pawn moves look a bit different
				if (move->fVictim) // Capture
					fprintf(f, "%cx%c%d", Col(move->fFromSquare),
							Col(move->fToSquare), Row(move->fToSquare));
				else // Move
					fprintf(f, "%c%d", Col(move->fToSquare), 
							Row(move->fToSquare));
				if (move->fPromotion) // Promotion?
					fprintf(f, "=%c ", sPieceChar[Piece(move->fPromotion)]);
				else
					fputc(' ', f);
			} else if (move->fCastling != kNoCastle) {
				if (move->fCastling == kCastleQueenside)
					fputs("O-O-O ", f);
				else
					fputs("O-O ", f);
			} else {
				MBCUnique u = [self disambiguateMove:move];
				fputc(sPieceChar[p], f);
				if (u) {
					if (u != (kMatchingPieceExists|kMatchingPieceOnSameCol))
						fputc(Col(move->fFromSquare), f);
					if (u & kMatchingPieceOnSameCol)
						fputc('0'+Row(move->fFromSquare), f);
				}
				if (move->fVictim) // Capture
					fputc('x', f);
				fprintf(f, "%c%d ", Col(move->fToSquare), Row(move->fToSquare));
			}
		}
		
		[self makeMove: move];
	}
	[existingMoves release];

	return YES;
}

- (BOOL) canPromote:(MBCSide)side
{
	MBCPiece 	piece;
	unsigned	rank;

	if (side == kBlackSide != ([fMoves count]&1))
		return NO;

	if (side == kBlackSide) {
		piece	= Black(PAWN);
		rank	= 2;
	} else {
		piece	= White(PAWN);
		rank 	= 7;
	}

	for (char file = 'a'; file < 'i'; ++file)
		if (What(fCurPos.fBoard[Square(file, rank)]) == piece)
			return YES;

	return NO;
}

- (BOOL) canUndo
{
	return [fMoves count] > 1;
}

- (MBCMove *) lastMove
{
	return [fMoves count] ? [fMoves lastObject] : nil;
}

- (int) numMoves
{
	return [fMoves count];
}

- (MBCMove *) move:(int)index
{
	return (index < (int)[fMoves count]) ? [fMoves objectAtIndex:index] : nil;
}

- (MBCPieces *) curPos
{
	return &fCurPos;
}

- (MBCPiece) defaultPromotion:(BOOL)white
{
	return fPromotion[white];
}

- (void) setDefaultPromotion:(MBCPiece)piece for:(BOOL)white
{
	fPromotion[white] = piece;
}

- (MBCMoveCode) outcome
{
    if (![fMoves count])
        return kCmdNull;
    
    MBCMove * lastMove = (MBCMove *)[fMoves lastObject];
    if (lastMove->fCheckMate) {
        if (fVariant == kVarLosers)
            return ([fMoves count] & 1) ? kCmdBlackWins : kCmdWhiteWins;
        else
            return ([fMoves count] & 1) ? kCmdWhiteWins : kCmdBlackWins;
    }
    if (fVariant == kVarSuicide || fVariant == kVarLosers) {
        if (!lastMove->fVictim) 
            return kCmdNull;
        MBCPiece color = Opposite(Color(lastMove->fVictim));
        if (fVariant == kVarSuicide && !fCurPos.fInHand[color+KING])
            return kCmdNull;
        if (fCurPos.NoPieces(Color(lastMove->fVictim))) 
            return ([fMoves count] & 1) ? kCmdBlackWins : kCmdWhiteWins;
    }
    if (fVariant != kVarSuicide) {
        MBCMoveGenerator	checkChecker(nil, fVariant, 0);
        if (checkChecker.InStaleMate(!([fMoves count] & 1), fCurPos))
            return fVariant != kVarLosers ? kCmdDraw
            : ([fMoves count] & 1) ? kCmdBlackWins : kCmdWhiteWins;
        if (fCurPos.NoPieces(kWhitePiece) && fCurPos.NoPieces(kBlackPiece))
            return kCmdDraw;
    }
    
    return kCmdNull;
}

NSString * LocalizedString(NSDictionary * localization, NSString * key, NSString * fallback)
{
	NSString * value = [[localization valueForKey:@"strings"] valueForKey:key];
    
	return value ? value : fallback;
}

NSString * LocalizedStringWithFormat(NSDictionary * localization, NSString * format, ...)
{
    va_list args;
    va_start(args, format);
    NSString * s = [[NSString alloc] initWithFormat:format locale:[localization valueForKey:@"locale"]
                                          arguments:args];
    va_end(args);
    
    return [s autorelease];
}

BOOL OldSquares(NSString * fmtString)
{
	/* We used to specify squares as "%c %d", now we use "%@ %@". To avoid
     breakage during the transition, we allow both 
     */
	NSRange r = [fmtString rangeOfString:@"%c"];
	if (r.length)
		return YES;
	r = [fmtString rangeOfString:@"$c"];
	if (r.length)
		return YES;	
    
	return NO;
}

static NSString *	sPieceName[] = {
	@"", @"king", @"queen", @"bishop", @"knight", @"rook", @"pawn"
};

static NSString * 	sFileKey[] = {
	@"file_a", @"file_b", @"file_c", @"file_d", @"file_e", @"file_f", @"file_g", @"file_h"
};

static NSString * 	sFileDefault[] = {
	@"A", @"B", @"C", @"D", @"E", @"F", @"G", @"H"
};

#define LOC_FILE(f) LOC(sFileKey[(f)-'a'], sFileDefault[(f)-'a'])

static NSString * 	sRankKey[] = {
	@"rank_1", @"rank_2", @"rank_3", @"rank_4", @"rank_5", @"rank_6", @"rank_7", @"rank_8"
};

static NSString * 	sRankDefault[] = {
	@"1", @"2", @"3", @"4", @"5", @"6", @"7", @"8"
};

#define LOC_RANK(r) LOC(sRankKey[(r)-1], sRankDefault[(r)-1])

- (NSString *)stringFromMove:(MBCMove *)move withLocalization:(NSDictionary *)localization
{
    switch (move->fCommand) {
    case kCmdDrop: {
        NSString * format  	= LOC(@"drop_fmt", @"%@ %c %d.");
        NSString * pkey 	= [NSString stringWithFormat:@"%@_d", sPieceName[Piece(move->fPiece)]];
        NSString * pdef 	= [NSString stringWithFormat:@"drop @% at", sPieceName[Piece(move->fPiece)]];
        NSString * ploc 	= LOC(pkey, pdef);
        char	   col  	= Col(move->fToSquare);
        int		   row  	= Row(move->fToSquare);
        if (OldSquares(format)) 
            return LocalizedStringWithFormat(localization, format, ploc, toupper(col), row);
        else
            return LocalizedStringWithFormat(localization, format, ploc, LOC_FILE(col), LOC_RANK(row));
    }
    case kCmdPMove:
    case kCmdMove: {
        MBCPiece	piece;
        MBCPiece	victim;
        MBCPiece	promo;

        if (move->fCastling == kUnknownCastle)
            move->fCastling = [self tryCastling:move];
        switch (move->fCastling) {
        case kCastleQueenside:
            return LOC(@"qcastle_fmt", @"Castle [[emph +]]queen side.");
        case kCastleKingside:
            return LOC(@"kcastle_fmt", @"Castle [[emph +]]king side.");
        default: 
            if (move->fPiece) { // Move already executed
                piece 	= move->fPiece;
                victim	= move->fVictim;
            } else {
                piece = fCurPos.fBoard[move->fFromSquare];
                victim= fCurPos.fBoard[move->fToSquare];
            }
            promo	= move->fPromotion;
            NSString * pname = LOC(sPieceName[Piece(piece)], sPieceName[Piece(piece)]);
            char	   fcol  = Col(move->fFromSquare);
            int	   frow  = Row(move->fFromSquare);
            char	   tcol  = Col(move->fToSquare);
            int	   trow  = Row(move->fToSquare);
            if (promo) {
                NSString * format = victim
                ? LOC(@"cpromo_fmt", @"%@ %c %d takes %c %d %@.")
                : LOC(@"promo_fmt", @"%@ %c %d to %c %d %@.");
                NSString * pkey  = [NSString stringWithFormat:@"%@_p", sPieceName[Piece(promo)]];
                NSString * pdef  = [NSString stringWithFormat:@"promoting to %@", sPieceName[Piece(promo)]];
                NSString * ploc  = LOC(pkey, pdef);
                
                if (OldSquares(format))
                    return LocalizedStringWithFormat(localization, format, pname,
                            toupper(fcol), frow, toupper(tcol), trow, 
                            ploc);
                else
                    return LocalizedStringWithFormat(localization, format, pname,
                            LOC_FILE(fcol), LOC_RANK(frow), LOC_FILE(tcol), LOC_RANK(trow),
                            ploc);
            } else {
                NSString * format = victim
                ? LOC(@"cmove_fmt", @"%@ %c %d takes %c %d.")
                : LOC(@"move_fmt", @"%@ %c %d to %c %d.");
                
               if (OldSquares(format))
                    return LocalizedStringWithFormat(localization, format, pname,
                            toupper(fcol), frow, toupper(tcol), trow);
                else
                    return LocalizedStringWithFormat(localization, format, pname,
                            LOC_FILE(fcol), LOC_RANK(frow), LOC_FILE(tcol), LOC_RANK(trow));
            }
        }}
    case kCmdWhiteWins:
        switch (fVariant) {
        default:
            if ([fMoves count] && ((MBCMove *)[fMoves lastObject])->fCheckMate)
                return LOC(@"check_mate", @"[[emph +]]Check mate!");
            //
            // Fall through
            //
        case kVarSuicide:
        case kVarLosers:
            return LOC(@"white_win", @"White wins!");
        }
    case kCmdBlackWins:
        switch (fVariant) {
        default:
            if ([fMoves count] && ((MBCMove *)[fMoves lastObject])->fCheckMate)
                return LOC(@"check_mate", @"[[emph +]]Check mate!");
            //
            // Fall through
            //
        case kVarSuicide:
        case kVarLosers:
            return LOC(@"black_win", @"Black wins!");
        }
    case kCmdDraw:
        return LOC(@"draw", @"The game is a draw!");
    default:
        return @"";
	}
}

- (NSString *)extStringFromMove:(MBCMove *)move withLocalization:(NSDictionary *)localization
{
    NSString * basic = [self stringFromMove:move withLocalization:localization];
    NSString * ext;
    
    if (move->fCheck || move->fCheckMate) {
        NSString * fmt  = LOC(@"has_check_fmt", @"%@, %@");
        NSString * check= move->fCheckMate ? LOC(@"check_mate", @"check mate!") : LOC(@"check", @"check!");
        
        ext = LocalizedStringWithFormat(localization, fmt, basic, check);
    } else {
        NSString * fmt  = LOC(@"no_check_fmt", @"%@.");
        
        ext = LocalizedStringWithFormat(localization, fmt, basic);
    }
    
    static NSRegularExpression * sFilter;
    if (!sFilter)
        sFilter = [[NSRegularExpression alloc] initWithPattern:@"\\[\\[.*?\\]\\]" options:0 error:nil];
    return [sFilter stringByReplacingMatchesInString:ext options:0 
                                               range:NSMakeRange(0, [ext length]) withTemplate:@""];
}

@end

inline MBCCompactMove EncodeCompactMove(
			 MBCMoveCode cmd, MBCSquare from, MBCSquare to, MBCPiece piece)
{
	return (cmd << 24) | (from << 16) | (to << 8) | piece;
}

inline MBCCompactMove EncodeCompactCommand(MBCMoveCode cmd)
{
	return cmd << 24;
}

MBCCompactMove MBCEncodeMove(const char * mv, int ponder)
{
	const char * 	piece	= " kqbnrp ";
	const char * 	p;
	MBCPiece		promo	= EMPTY;

	if (mv[4] && (p = strchr(piece, mv[4])))
		promo	= p-piece;

	return EncodeCompactMove(ponder ? kCmdPMove : kCmdMove,
							 Square(mv+0), Square(mv+2), promo);
}

MBCCompactMove MBCEncodeDrop(const char * drop, int ponder)
{
	const char * 	piece	= " KQBNRP  kqbnrp ";
	
	return EncodeCompactMove(ponder ? kCmdPDrop : kCmdDrop,
							 0, Square(drop+2),
							 strchr(piece, drop[0])-piece);
}

MBCCompactMove MBCEncodeIllegal()
{
	return EncodeCompactCommand(kCmdUndo);
}

MBCCompactMove MBCEncodeLegal()
{
	return EncodeCompactCommand(kCmdMoveOK);
}

MBCCompactMove MBCEncodePong()
{
	return EncodeCompactCommand(kCmdPong);
}

MBCCompactMove MBCEncodeStartGame()
{
	return EncodeCompactCommand(kCmdStartGame);
}

MBCCompactMove MBCEncodeWhiteWins()
{
	return EncodeCompactCommand(kCmdWhiteWins);
}

MBCCompactMove MBCEncodeBlackWins()
{
	return EncodeCompactCommand(kCmdBlackWins);
}

MBCCompactMove MBCEncodeDraw()
{
	return EncodeCompactCommand(kCmdDraw);
}

MBCCompactMove MBCEncodeTakeback()
{
	return EncodeCompactCommand(kCmdUndo);
}

// Local Variables:
// mode:ObjC
// End: