/*
CuckooChess - A java chess program.
Copyright (C) 2011 Peter Österlund, peterosterlund2@gmail.com
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package chess;
import java.util.Locale;
public class TextIO {
static public final String startPosFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1";
/** Parse a FEN string and return a chess Position object. */
public static final Position readFEN(String fen) throws ChessParseError {
Position pos = new Position();
String[] words = fen.split(" ");
if (words.length < 2) {
throw new ChessParseError("Too few spaces");
}
// Piece placement
int row = 7;
int col = 0;
for (int i = 0; i < words[0].length(); i++) {
char c = words[0].charAt(i);
switch (c) {
case '1': col += 1; break;
case '2': col += 2; break;
case '3': col += 3; break;
case '4': col += 4; break;
case '5': col += 5; break;
case '6': col += 6; break;
case '7': col += 7; break;
case '8': col += 8; break;
case '/': row--; col = 0; break;
case 'P': safeSetPiece(pos, col, row, Piece.WPAWN); col++; break;
case 'N': safeSetPiece(pos, col, row, Piece.WKNIGHT); col++; break;
case 'B': safeSetPiece(pos, col, row, Piece.WBISHOP); col++; break;
case 'R': safeSetPiece(pos, col, row, Piece.WROOK); col++; break;
case 'Q': safeSetPiece(pos, col, row, Piece.WQUEEN); col++; break;
case 'K': safeSetPiece(pos, col, row, Piece.WKING); col++; break;
case 'p': safeSetPiece(pos, col, row, Piece.BPAWN); col++; break;
case 'n': safeSetPiece(pos, col, row, Piece.BKNIGHT); col++; break;
case 'b': safeSetPiece(pos, col, row, Piece.BBISHOP); col++; break;
case 'r': safeSetPiece(pos, col, row, Piece.BROOK); col++; break;
case 'q': safeSetPiece(pos, col, row, Piece.BQUEEN); col++; break;
case 'k': safeSetPiece(pos, col, row, Piece.BKING); col++; break;
default: throw new ChessParseError("Invalid piece");
}
}
if (words[1].length() == 0) {
throw new ChessParseError("Invalid side");
}
pos.setWhiteMove(words[1].charAt(0) == 'w');
// Castling rights
int castleMask = 0;
if (words.length > 2) {
for (int i = 0; i < words[2].length(); i++) {
char c = words[2].charAt(i);
switch (c) {
case 'K':
castleMask |= (1 << Position.H1_CASTLE);
break;
case 'Q':
castleMask |= (1 << Position.A1_CASTLE);
break;
case 'k':
castleMask |= (1 << Position.H8_CASTLE);
break;
case 'q':
castleMask |= (1 << Position.A8_CASTLE);
break;
case '-':
break;
default:
throw new ChessParseError("Invalid castling flags");
}
}
}
pos.setCastleMask(castleMask);
if (words.length > 3) {
// En passant target square
String epString = words[3];
if (!epString.equals("-")) {
if (epString.length() < 2) {
throw new ChessParseError("Invalid en passant square");
}
pos.setEpSquare(getSquare(epString));
}
}
try {
if (words.length > 4) {
pos.halfMoveClock = Integer.parseInt(words[4]);
}
if (words.length > 5) {
pos.fullMoveCounter = Integer.parseInt(words[5]);
}
} catch (NumberFormatException nfe) {
// Ignore errors here, since the fields are optional
}
// Each side must have exactly one king
int wKings = 0;
int bKings = 0;
for (int x = 0; x < 8; x++) {
for (int y = 0; y < 8; y++) {
int p = pos.getPiece(Position.getSquare(x, y));
if (p == Piece.WKING) {
wKings++;
} else if (p == Piece.BKING) {
bKings++;
}
}
}
if (wKings != 1) {
throw new ChessParseError("White must have exactly one king");
}
if (bKings != 1) {
throw new ChessParseError("Black must have exactly one king");
}
// Make sure king can not be captured
Position pos2 = new Position(pos);
pos2.setWhiteMove(!pos.whiteMove);
if (MoveGen.inCheck(pos2)) {
throw new ChessParseError("King capture possible");
}
fixupEPSquare(pos);
return pos;
}
/** Remove pseudo-legal EP square if it is not legal, ie would leave king in check. */
public static final void fixupEPSquare(Position pos) {
int epSquare = pos.getEpSquare();
if (epSquare >= 0) {
MoveGen.MoveList moves = MoveGen.instance.pseudoLegalMoves(pos);
MoveGen.removeIllegal(pos, moves);
boolean epValid = false;
for (int mi = 0; mi < moves.size; mi++) {
Move m = moves.m[mi];
if (m.to == epSquare) {
if (pos.getPiece(m.from) == (pos.whiteMove ? Piece.WPAWN : Piece.BPAWN)) {
epValid = true;
break;
}
}
}
if (!epValid) {
pos.setEpSquare(-1);
}
}
}
private static final void safeSetPiece(Position pos, int col, int row, int p) throws ChessParseError {
if (row < 0) throw new ChessParseError("Too many rows");
if (col > 7) throw new ChessParseError("Too many columns");
if ((p == Piece.WPAWN) || (p == Piece.BPAWN)) {
if ((row == 0) || (row == 7))
throw new ChessParseError("Pawn on first/last rank");
}
pos.setPiece(Position.getSquare(col, row), p);
}
/** Return a FEN string corresponding to a chess Position object. */
public static final String toFEN(Position pos) {
StringBuilder ret = new StringBuilder();
// Piece placement
for (int r = 7; r >=0; r--) {
int numEmpty = 0;
for (int c = 0; c < 8; c++) {
int p = pos.getPiece(Position.getSquare(c, r));
if (p == Piece.EMPTY) {
numEmpty++;
} else {
if (numEmpty > 0) {
ret.append(numEmpty);
numEmpty = 0;
}
switch (p) {
case Piece.WKING: ret.append('K'); break;
case Piece.WQUEEN: ret.append('Q'); break;
case Piece.WROOK: ret.append('R'); break;
case Piece.WBISHOP: ret.append('B'); break;
case Piece.WKNIGHT: ret.append('N'); break;
case Piece.WPAWN: ret.append('P'); break;
case Piece.BKING: ret.append('k'); break;
case Piece.BQUEEN: ret.append('q'); break;
case Piece.BROOK: ret.append('r'); break;
case Piece.BBISHOP: ret.append('b'); break;
case Piece.BKNIGHT: ret.append('n'); break;
case Piece.BPAWN: ret.append('p'); break;
default: throw new RuntimeException();
}
}
}
if (numEmpty > 0) {
ret.append(numEmpty);
}
if (r > 0) {
ret.append('/');
}
}
ret.append(pos.whiteMove ? " w " : " b ");
// Castling rights
boolean anyCastle = false;
if (pos.h1Castle()) {
ret.append('K');
anyCastle = true;
}
if (pos.a1Castle()) {
ret.append('Q');
anyCastle = true;
}
if (pos.h8Castle()) {
ret.append('k');
anyCastle = true;
}
if (pos.a8Castle()) {
ret.append('q');
anyCastle = true;
}
if (!anyCastle) {
ret.append('-');
}
// En passant target square
{
ret.append(' ');
if (pos.getEpSquare() >= 0) {
int x = Position.getX(pos.getEpSquare());
int y = Position.getY(pos.getEpSquare());
ret.append((char)(x + 'a'));
ret.append((char)(y + '1'));
} else {
ret.append('-');
}
}
// Move counters
ret.append(' ');
ret.append(pos.halfMoveClock);
ret.append(' ');
ret.append(pos.fullMoveCounter);
return ret.toString();
}
/**
* Convert a chess move to human readable form.
* @param pos The chess position.
* @param move The executed move.
* @param longForm If true, use long notation, eg Ng1-f3.
* Otherwise, use short notation, eg Nf3
*/
public static final String moveToString(Position pos, Move move, boolean longForm) {
MoveGen.MoveList moves = MoveGen.instance.pseudoLegalMoves(pos);
MoveGen.removeIllegal(pos, moves);
return moveToString(pos, move, longForm, moves);
}
private static final String moveToString(Position pos, Move move, boolean longForm, MoveGen.MoveList moves) {
StringBuilder ret = new StringBuilder();
int wKingOrigPos = Position.getSquare(4, 0);
int bKingOrigPos = Position.getSquare(4, 7);
if (move.from == wKingOrigPos && pos.getPiece(wKingOrigPos) == Piece.WKING) {
// Check white castle
if (move.to == Position.getSquare(6, 0)) {
ret.append("O-O");
} else if (move.to == Position.getSquare(2, 0)) {
ret.append("O-O-O");
}
} else if (move.from == bKingOrigPos && pos.getPiece(bKingOrigPos) == Piece.BKING) {
// Check black castle
if (move.to == Position.getSquare(6, 7)) {
ret.append("O-O");
} else if (move.to == Position.getSquare(2, 7)) {
ret.append("O-O-O");
}
}
if (ret.length() == 0) {
int p = pos.getPiece(move.from);
ret.append(pieceToChar(p));
int x1 = Position.getX(move.from);
int y1 = Position.getY(move.from);
int x2 = Position.getX(move.to);
int y2 = Position.getY(move.to);
if (longForm) {
ret.append((char)(x1 + 'a'));
ret.append((char) (y1 + '1'));
ret.append(isCapture(pos, move) ? 'x' : '-');
} else {
if (p == (pos.whiteMove ? Piece.WPAWN : Piece.BPAWN)) {
if (isCapture(pos, move)) {
ret.append((char) (x1 + 'a'));
}
} else {
int numSameTarget = 0;
int numSameFile = 0;
int numSameRow = 0;
for (int mi = 0; mi < moves.size; mi++) {
Move m = moves.m[mi];
if (m == null)
break;
if ((pos.getPiece(m.from) == p) && (m.to == move.to)) {
numSameTarget++;
if (Position.getX(m.from) == x1)
numSameFile++;
if (Position.getY(m.from) == y1)
numSameRow++;
}
}
if (numSameTarget < 2) {
// No file/row info needed
} else if (numSameFile < 2) {
ret.append((char) (x1 + 'a')); // Only file info needed
} else if (numSameRow < 2) {
ret.append((char) (y1 + '1')); // Only row info needed
} else {
ret.append((char) (x1 + 'a')); // File and row info needed
ret.append((char) (y1 + '1'));
}
}
if (isCapture(pos, move)) {
ret.append('x');
}
}
ret.append((char) (x2 + 'a'));
ret.append((char) (y2 + '1'));
if (move.promoteTo != Piece.EMPTY) {
ret.append(pieceToChar(move.promoteTo));
}
}
UndoInfo ui = new UndoInfo();
if (MoveGen.givesCheck(pos, move)) {
pos.makeMove(move, ui);
MoveGen.MoveList nextMoves = MoveGen.instance.pseudoLegalMoves(pos);
MoveGen.removeIllegal(pos, nextMoves);
if (nextMoves.size == 0) {
ret.append('#');
} else {
ret.append('+');
}
pos.unMakeMove(move, ui);
}
return ret.toString();
}
/** Convert a move object to UCI string format. */
public static final String moveToUCIString(Move m) {
String ret = squareToString(m.from);
ret += squareToString(m.to);
switch (m.promoteTo) {
case Piece.WQUEEN:
case Piece.BQUEEN:
ret += "q";
break;
case Piece.WROOK:
case Piece.BROOK:
ret += "r";
break;
case Piece.WBISHOP:
case Piece.BBISHOP:
ret += "b";
break;
case Piece.WKNIGHT:
case Piece.BKNIGHT:
ret += "n";
break;
default:
break;
}
return ret;
}
/**
* Convert a string to a Move object.
* @return A move object, or null if move has invalid syntax
*/
public static final Move uciStringToMove(String move) {
Move m = null;
if ((move.length() < 4) || (move.length() > 5))
return m;
int fromSq = TextIO.getSquare(move.substring(0, 2));
int toSq = TextIO.getSquare(move.substring(2, 4));
if ((fromSq < 0) || (toSq < 0)) {
return m;
}
char prom = ' ';
boolean white = true;
if (move.length() == 5) {
prom = move.charAt(4);
if (Position.getY(toSq) == 7) {
white = true;
} else if (Position.getY(toSq) == 0) {
white = false;
} else {
return m;
}
}
int promoteTo;
switch (prom) {
case ' ':
promoteTo = Piece.EMPTY;
break;
case 'q':
promoteTo = white ? Piece.WQUEEN : Piece.BQUEEN;
break;
case 'r':
promoteTo = white ? Piece.WROOK : Piece.BROOK;
break;
case 'b':
promoteTo = white ? Piece.WBISHOP : Piece.BBISHOP;
break;
case 'n':
promoteTo = white ? Piece.WKNIGHT : Piece.BKNIGHT;
break;
default:
return m;
}
m = new Move(fromSq, toSq, promoteTo);
return m;
}
private static final boolean isCapture(Position pos, Move move) {
if (pos.getPiece(move.to) == Piece.EMPTY) {
int p = pos.getPiece(move.from);
if ((p == (pos.whiteMove ? Piece.WPAWN : Piece.BPAWN)) && (move.to == pos.getEpSquare())) {
return true;
} else {
return false;
}
} else {
return true;
}
}
/**
* Convert a chess move string to a Move object.
* Any prefix of the string representation of a valid move counts as a legal move string,
* as long as the string only matches one valid move.
*/
public static final Move stringToMove(Position pos, String strMove) {
strMove = strMove.replaceAll("=", "");
Move move = null;
if (strMove.length() == 0)
return move;
MoveGen.MoveList moves = MoveGen.instance.pseudoLegalMoves(pos);
MoveGen.removeIllegal(pos, moves);
{
char lastChar = strMove.charAt(strMove.length() - 1);
if ((lastChar == '#') || (lastChar == '+')) {
MoveGen.MoveList subMoves = new MoveGen.MoveList();
int len = 0;
for (int mi = 0; mi < moves.size; mi++) {
Move m = moves.m[mi];
String str1 = TextIO.moveToString(pos, m, true, moves);
if (str1.charAt(str1.length() - 1) == lastChar) {
subMoves.m[len++] = m;
}
}
subMoves.size = len;
moves = subMoves;
strMove = normalizeMoveString(strMove);
}
}
for (int i = 0; i < 2; i++) {
// Search for full match
for (int mi = 0; mi < moves.size; mi++) {
Move m = moves.m[mi];
String str1 = normalizeMoveString(TextIO.moveToString(pos, m, true, moves));
String str2 = normalizeMoveString(TextIO.moveToString(pos, m, false, moves));
if (i == 0) {
if (strMove.equals(str1) || strMove.equals(str2)) {
return m;
}
} else {
if (strMove.toLowerCase().equals(str1.toLowerCase()) ||
strMove.toLowerCase().equals(str2.toLowerCase())) {
return m;
}
}
}
}
for (int i = 0; i < 2; i++) {
// Search for unique substring match
for (int mi = 0; mi < moves.size; mi++) {
Move m = moves.m[mi];
String str1 = normalizeMoveString(TextIO.moveToString(pos, m, true));
String str2 = normalizeMoveString(TextIO.moveToString(pos, m, false));
boolean match;
if (i == 0) {
match = (str1.startsWith(strMove) || str2.startsWith(strMove));
} else {
match = (str1.toLowerCase().startsWith(strMove.toLowerCase()) ||
str2.toLowerCase().startsWith(strMove.toLowerCase()));
}
if (match) {
if (move != null) {
return null; // More than one match, not ok
} else {
move = m;
}
}
}
if (move != null)
return move;
}
return move;
}
/**
* Convert a string, such as "e4" to a square number.
* @return The square number, or -1 if not a legal square.
*/
public static final int getSquare(String s) {
int x = s.charAt(0) - 'a';
int y = s.charAt(1) - '1';
if ((x < 0) || (x > 7) || (y < 0) || (y > 7))
return -1;
return Position.getSquare(x, y);
}
/**
* Convert a square number to a string, such as "e4".
*/
public static final String squareToString(int square) {
StringBuilder ret = new StringBuilder();
int x = Position.getX(square);
int y = Position.getY(square);
ret.append((char) (x + 'a'));
ret.append((char) (y + '1'));
return ret.toString();
}
/**
* Create an ascii representation of a position.
*/
public static final String asciiBoard(Position pos) {
StringBuilder ret = new StringBuilder(400);
String nl = String.format(Locale.US, "%n");
ret.append(" +----+----+----+----+----+----+----+----+"); ret.append(nl);
for (int y = 7; y >= 0; y--) {
ret.append(" |");
for (int x = 0; x < 8; x++) {
ret.append(' ');
int p = pos.getPiece(Position.getSquare(x, y));
if (p == Piece.EMPTY) {
boolean dark = Position.darkSquare(x, y);
ret.append(dark ? ".. |" : " |");
} else {
ret.append(Piece.isWhite(p) ? ' ' : '*');
String pieceName = pieceToChar(p);
if (pieceName.length() == 0)
pieceName = "P";
ret.append(pieceName);
ret.append(" |");
}
}
ret.append(nl);
ret.append(" +----+----+----+----+----+----+----+----+");
ret.append(nl);
}
return ret.toString();
}
/**
* Convert move string to lower case and remove special check/mate symbols.
*/
private static final String normalizeMoveString(String str) {
if (str.length() > 0) {
char lastChar = str.charAt(str.length() - 1);
if ((lastChar == '#') || (lastChar == '+')) {
str = str.substring(0, str.length() - 1);
}
}
return str;
}
private final static String pieceToChar(int p) {
switch (p) {
case Piece.WQUEEN: case Piece.BQUEEN: return "Q";
case Piece.WROOK: case Piece.BROOK: return "R";
case Piece.WBISHOP: case Piece.BBISHOP: return "B";
case Piece.WKNIGHT: case Piece.BKNIGHT: return "N";
case Piece.WKING: case Piece.BKING: return "K";
}
return "";
}
}