/* DroidFish - An Android chess program. Copyright (C) 2011 Peter Ă–sterlund, 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 org.petero.droidfish.gamelogic; import java.util.ArrayList; import java.util.List; import java.util.Locale; import org.petero.droidfish.PGNOptions; import org.petero.droidfish.R; /** * Handle conversion of positions and moves to/from text format. * @author petero */ public class TextIO { static public final String startPosFEN = "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1"; /** Localized version of "P N B R Q K". */ private static String[] pieceNames = null; /** Set localized piece names. */ public static final void setPieceNames(String pieceNames) { String[] pn = pieceNames.split(" "); if (pn.length == 6) TextIO.pieceNames = pn; } /** Parse a FEN string and return a chess Position object. */ public static final Position readFEN(String fen) throws ChessParseError { fen = fen.trim(); Position pos = new Position(); String[] words = fen.split(" "); if (words.length < 2) { throw new ChessParseError(R.string.err_too_few_spaces); } for (int i = 0; i < words.length; i++) { words[i] = words[i].trim(); } // 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(R.string.err_invalid_piece, pos); } } if (words[1].length() > 0) { boolean wtm; switch (words[1].charAt(0)) { case 'w': wtm = true; break; case 'b': wtm = false; break; default: throw new ChessParseError(R.string.err_invalid_side, pos); } pos.setWhiteMove(wtm); } else { throw new ChessParseError(R.string.err_invalid_side, pos); } // 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(R.string.err_invalid_castling_flags, pos); } } } pos.setCastleMask(castleMask); removeBogusCastleFlags(pos); if (words.length > 3) { // En passant target square String epString = words[3]; if (!epString.equals("-")) { if (epString.length() < 2) { throw new ChessParseError(R.string.err_invalid_en_passant_square, pos); } 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[] nPieces = new int[Piece.nPieceTypes]; for (int i = 0; i < Piece.nPieceTypes; i++) nPieces[i] = 0; for (int x = 0; x < 8; x++) for (int y = 0; y < 8; y++) nPieces[pos.getPiece(Position.getSquare(x, y))]++; if (nPieces[Piece.WKING] != 1) throw new ChessParseError(R.string.err_white_num_kings, pos); if (nPieces[Piece.BKING] != 1) throw new ChessParseError(R.string.err_black_num_kings, pos); // White must not have too many pieces int maxWPawns = 8; maxWPawns -= Math.max(0, nPieces[Piece.WKNIGHT] - 2); maxWPawns -= Math.max(0, nPieces[Piece.WBISHOP] - 2); maxWPawns -= Math.max(0, nPieces[Piece.WROOK ] - 2); maxWPawns -= Math.max(0, nPieces[Piece.WQUEEN ] - 1); if (nPieces[Piece.WPAWN] > maxWPawns) throw new ChessParseError(R.string.err_too_many_white_pieces, pos); // Black must not have too many pieces int maxBPawns = 8; maxBPawns -= Math.max(0, nPieces[Piece.BKNIGHT] - 2); maxBPawns -= Math.max(0, nPieces[Piece.BBISHOP] - 2); maxBPawns -= Math.max(0, nPieces[Piece.BROOK ] - 2); maxBPawns -= Math.max(0, nPieces[Piece.BQUEEN ] - 1); if (nPieces[Piece.BPAWN] > maxBPawns) throw new ChessParseError(R.string.err_too_many_black_pieces, pos); // Make sure king can not be captured Position pos2 = new Position(pos); pos2.setWhiteMove(!pos.whiteMove); if (MoveGen.inCheck(pos2)) { throw new ChessParseError(R.string.err_king_capture_possible, pos); } fixupEPSquare(pos); return pos; } public static final void removeBogusCastleFlags(Position pos) { int castleMask = pos.getCastleMask(); int validCastle = 0; if (pos.getPiece(4) == Piece.WKING) { if (pos.getPiece(0) == Piece.WROOK) validCastle |= (1 << Position.A1_CASTLE); if (pos.getPiece(7) == Piece.WROOK) validCastle |= (1 << Position.H1_CASTLE); } if (pos.getPiece(60) == Piece.BKING) { if (pos.getPiece(56) == Piece.BROOK) validCastle |= (1 << Position.A8_CASTLE); if (pos.getPiece(63) == Piece.BROOK) validCastle |= (1 << Position.H8_CASTLE); } castleMask &= validCastle; pos.setCastleMask(castleMask); } /** 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) { ArrayList<Move> moves = MoveGen.instance.legalMoves(pos); boolean epValid = false; for (Move m : moves) { 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(R.string.err_too_many_rows); if (col > 7) throw new ChessParseError(R.string.err_too_many_columns); if ((p == Piece.WPAWN) || (p == Piece.BPAWN)) { if ((row == 0) || (row == 7)) throw new ChessParseError(R.string.err_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. * @param localized If true, use localized piece names. */ public static final String moveToString(Position pos, Move move, boolean longForm, boolean localized) { return moveToString(pos, move, longForm, localized, null); } public static final String moveToString(Position pos, Move move, boolean longForm, boolean localized, List<Move> moves) { if ((move == null) || move.equals(new Move(0, 0, 0))) return "--"; 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) { if (pieceNames == null) localized = false; int p = pos.getPiece(move.from); if (localized) ret.append(pieceToCharLocalized(p)); else 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; if (moves == null) moves = MoveGen.instance.legalMoves(pos); int mSize = moves.size(); for (int mi = 0; mi < mSize; mi++) { Move m = moves.get(mi); 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) { if (localized) ret.append(pieceToCharLocalized(move.promoteTo)); else ret.append(pieceToChar(move.promoteTo)); } } UndoInfo ui = new UndoInfo(); pos.makeMove(move, ui); boolean givesCheck = MoveGen.inCheck(pos); if (givesCheck) { ArrayList<Move> nextMoves = MoveGen.instance.legalMoves(pos); if (nextMoves.size() == 0) { ret.append('#'); } else { ret.append('+'); } } pos.unMakeMove(move, ui); return ret.toString(); } 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; } } /** * Decide if move is valid in position pos. * @param pos Position for which to test move. * @param move The move to check for validity. * @param moves If non-null, list of valid moves in position pos. * @return True if move is valid in position pos, false otherwise. */ public static final boolean isValid(Position pos, Move move) { if (move == null) return false; ArrayList<Move> moves = new MoveGen().legalMoves(pos); for (int i = 0; i < moves.size(); i++) if (move.equals(moves.get(i))) return true; return false; } private final static class MoveInfo { int piece; // -1 for unspecified int fromX, fromY, toX, toY; // -1 for unspecified int promPiece; // -1 for unspecified MoveInfo() { piece = fromX = fromY = toX = toY = promPiece = -1; } } /** * Convert a chess move string to a Move object. * The string may specify any combination of piece/source/target/promotion * information as long as it matches exactly one valid move. */ public static final Move stringToMove(Position pos, String strMove) { return stringToMove(pos, strMove, null); } public static final Move stringToMove(Position pos, String strMove, ArrayList<Move> moves) { if (strMove.equals("--")) return new Move(0, 0, 0); strMove = strMove.replaceAll("=", ""); strMove = strMove.replaceAll("\\+", ""); strMove = strMove.replaceAll("#", ""); boolean wtm = pos.whiteMove; MoveInfo info = new MoveInfo(); boolean capture = false; if (strMove.equals("O-O") || strMove.equals("0-0") || strMove.equals("o-o")) { info.piece = wtm ? Piece.WKING : Piece.BKING; info.fromX = 4; info.toX = 6; info.fromY = info.toY = wtm ? 0 : 7; info.promPiece = Piece.EMPTY; } else if (strMove.equals("O-O-O") || strMove.equals("0-0-0") || strMove.equals("o-o-o")) { info.piece = wtm ? Piece.WKING : Piece.BKING; info.fromX = 4; info.toX = 2; info.fromY = info.toY = wtm ? 0 : 7; info.promPiece = Piece.EMPTY; } else { boolean atToSq = false; for (int i = 0; i < strMove.length(); i++) { char c = strMove.charAt(i); if (i == 0) { int piece = charToPiece(wtm, c); if (piece >= 0) { info.piece = piece; continue; } } int tmpX = c - 'a'; if ((tmpX >= 0) && (tmpX < 8)) { if (atToSq || (info.fromX >= 0)) info.toX = tmpX; else info.fromX = tmpX; } int tmpY = c - '1'; if ((tmpY >= 0) && (tmpY < 8)) { if (atToSq || (info.fromY >= 0)) info.toY = tmpY; else info.fromY = tmpY; } if ((c == 'x') || (c == '-')) { atToSq = true; if (c == 'x') capture = true; } if (i == strMove.length() - 1) { int promPiece = charToPiece(wtm, c); if (promPiece >= 0) { info.promPiece = promPiece; } } } if ((info.fromX >= 0) && (info.toX < 0)) { info.toX = info.fromX; info.fromX = -1; } if ((info.fromY >= 0) && (info.toY < 0)) { info.toY = info.fromY; info.fromY = -1; } if (info.piece < 0) { boolean haveAll = (info.fromX >= 0) && (info.fromY >= 0) && (info.toX >= 0) && (info.toY >= 0); if (!haveAll) info.piece = wtm ? Piece.WPAWN : Piece.BPAWN; } if (info.promPiece < 0) info.promPiece = Piece.EMPTY; } if (moves == null) moves = MoveGen.instance.legalMoves(pos); ArrayList<Move> matches = new ArrayList<Move>(2); for (int i = 0; i < moves.size(); i++) { Move m = moves.get(i); int p = pos.getPiece(m.from); boolean match = true; if ((info.piece >= 0) && (info.piece != p)) match = false; if ((info.fromX >= 0) && (info.fromX != Position.getX(m.from))) match = false; if ((info.fromY >= 0) && (info.fromY != Position.getY(m.from))) match = false; if ((info.toX >= 0) && (info.toX != Position.getX(m.to))) match = false; if ((info.toY >= 0) && (info.toY != Position.getY(m.to))) match = false; if ((info.promPiece >= 0) && (info.promPiece != m.promoteTo)) match = false; if (match) { matches.add(m); } } int nMatches = matches.size(); if (nMatches == 0) return null; else if (nMatches == 1) return matches.get(0); if (!capture) return null; Move move = null; for (int i = 0; i < matches.size(); i++) { Move m = matches.get(i); int capt = pos.getPiece(m.to); if (capt != Piece.EMPTY) { if (move == null) move = m; else return null; } } return move; } /** 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 in UCI move format 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; } /** * 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 a piece and a square to a string, such as Nf3. */ public final static String pieceAndSquareToString(int currentPieceType, int p, int sq) { StringBuilder ret = new StringBuilder(); if (currentPieceType == PGNOptions.PT_FIGURINE) { ret.append(Piece.toUniCode(p)); } else { boolean localized = (currentPieceType != PGNOptions.PT_ENGLISH); if ((p == Piece.WPAWN) || (p == Piece.BPAWN)) ret.append(localized ? pieceNames[0] : "P"); else ret.append(localized ? pieceToCharLocalized(p) : pieceToChar(p)); } ret.append(squareToString(sq)); return ret.toString(); } 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 ""; } public final static String pieceToCharLocalized(int p) { switch (p) { case Piece.WQUEEN: case Piece.BQUEEN: return pieceNames[4]; case Piece.WROOK: case Piece.BROOK: return pieceNames[3]; case Piece.WBISHOP: case Piece.BBISHOP: return pieceNames[2]; case Piece.WKNIGHT: case Piece.BKNIGHT: return pieceNames[1]; case Piece.WKING: case Piece.BKING: return pieceNames[5]; } return ""; } private final static int charToPiece(boolean white, char c) { switch (c) { case 'Q': case 'q': return white ? Piece.WQUEEN : Piece.BQUEEN; case 'R': case 'r': return white ? Piece.WROOK : Piece.BROOK; case 'B': return white ? Piece.WBISHOP : Piece.BBISHOP; case 'N': case 'n': return white ? Piece.WKNIGHT : Piece.BKNIGHT; case 'K': case 'k': return white ? Piece.WKING : Piece.BKING; case 'P': case 'p': return white ? Piece.WPAWN : Piece.BPAWN; } return -1; } /** Add an = sign to a promotion move, as required by the PGN standard. */ public final static String pgnPromotion(String str) { int idx = str.length() - 1; while (idx > 0) { char c = str.charAt(idx); if ((c != '#') && (c != '+')) break; idx--; } if ((idx > 0) && (charToPiece(true, str.charAt(idx)) != -1)) idx--; return str.substring(0, idx + 1) + '=' + str.substring(idx + 1, str.length()); } }