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apiutil.h
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apiutil.h
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/*
Fairy-Stockfish, a UCI chess variant playing engine derived from Stockfish
Copyright (C) 2018-2022 Fabian Fichter
Fairy-Stockfish 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.
Fairy-Stockfish 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/>.
*/
#ifndef APIUTIL_H_INCLUDED
#define APIUTIL_H_INCLUDED
#include <array>
#include <vector>
#include <string>
#include <sstream>
#include <cctype>
#include <iostream>
#include <math.h>
#include "types.h"
#include "position.h"
#include "variant.h"
namespace Stockfish {
enum Notation {
NOTATION_DEFAULT,
// https://en.wikipedia.org/wiki/Algebraic_notation_(chess)
NOTATION_SAN,
NOTATION_LAN,
// https://en.wikipedia.org/wiki/Shogi_notation#Western_notation
NOTATION_SHOGI_HOSKING, // Examples: P76, S’34
NOTATION_SHOGI_HODGES, // Examples: P-7f, S*3d
NOTATION_SHOGI_HODGES_NUMBER, // Examples: P-76, S*34
// http://www.janggi.pl/janggi-notation/
NOTATION_JANGGI,
// https://en.wikipedia.org/wiki/Xiangqi#Notation
NOTATION_XIANGQI_WXF,
// https://web.archive.org/web/20180817205956/http://bgsthai.com/2018/05/07/lawofthaichessc/
NOTATION_THAI_SAN,
NOTATION_THAI_LAN,
};
inline Notation default_notation(const Variant* v) {
if (v->variantTemplate == "shogi")
return NOTATION_SHOGI_HODGES_NUMBER;
return NOTATION_SAN;
}
enum Termination {
ONGOING,
CHECKMATE,
STALEMATE,
INSUFFICIENT_MATERIAL,
N_MOVE_RULE,
N_FOLD_REPETITION,
VARIANT_END,
};
const std::array<std::string, 12> THAI_FILES = {"ก", "ข", "ค", "ง", "จ", "ฉ", "ช", "ญ", "ต", "ถ", "ธ", "น"};
const std::array<std::string, 12> THAI_RANKS = {"๑", "๒", "๓", "๔", "๕", "๖", "๗", "๘", "๙", "๑๐", "๑๑", "๑๒"};
namespace SAN {
enum Disambiguation {
NO_DISAMBIGUATION,
FILE_DISAMBIGUATION,
RANK_DISAMBIGUATION,
SQUARE_DISAMBIGUATION,
};
inline bool is_shogi(Notation n) {
return n == NOTATION_SHOGI_HOSKING || n == NOTATION_SHOGI_HODGES || n == NOTATION_SHOGI_HODGES_NUMBER;
}
inline bool is_thai(Notation n) {
return n == NOTATION_THAI_SAN || n == NOTATION_THAI_LAN;
}
// is there more than one file with a pair of pieces?
inline bool multi_tandem(Bitboard b) {
int tandems = 0;
for (File f = FILE_A; f <= FILE_MAX; ++f)
if (more_than_one(b & file_bb(f)))
tandems++;
return tandems >= 2;
}
inline std::string piece_to_thai_char(Piece pc, bool promoted) {
switch(type_of(pc)) {
case KING:
return "ข";
case KHON:
return "ค";
case FERS:
return promoted ? "ง" : "ม็";
case KNIGHT:
return "ม";
case ROOK:
return "ร";
case PAWN:
return "บ";
case AIWOK:
return "ว";
default:
return "X";
}
}
inline std::string piece(const Position& pos, Move m, Notation n) {
Color us = pos.side_to_move();
Square from = from_sq(m);
Piece pc = pos.moved_piece(m);
PieceType pt = type_of(pc);
// Quiet pawn moves
if ((n == NOTATION_SAN || n == NOTATION_LAN || n == NOTATION_THAI_SAN) && type_of(pc) == PAWN && type_of(m) != DROP)
return "";
// Tandem pawns
else if (n == NOTATION_XIANGQI_WXF && popcount(pos.pieces(us, pt) & file_bb(from)) >= 3 - multi_tandem(pos.pieces(us, pt)))
return std::to_string(popcount(forward_file_bb(us, from) & pos.pieces(us, pt)) + 1);
// Moves of promoted pieces
else if (is_shogi(n) && type_of(m) != DROP && pos.unpromoted_piece_on(from))
return "+" + std::string(1, toupper(pos.piece_to_char()[pos.unpromoted_piece_on(from)]));
// Promoted drops
else if (is_shogi(n) && type_of(m) == DROP && dropped_piece_type(m) != in_hand_piece_type(m))
return "+" + std::string(1, toupper(pos.piece_to_char()[in_hand_piece_type(m)]));
else if (is_thai(n))
return piece_to_thai_char(pc, pos.is_promoted(from));
else if (pos.piece_to_char_synonyms()[pc] != ' ')
return std::string(1, toupper(pos.piece_to_char_synonyms()[pc]));
else
return std::string(1, toupper(pos.piece_to_char()[pc]));
}
inline std::string file(const Position& pos, Square s, Notation n) {
switch (n)
{
case NOTATION_SHOGI_HOSKING:
case NOTATION_SHOGI_HODGES:
case NOTATION_SHOGI_HODGES_NUMBER:
return std::to_string(pos.max_file() - file_of(s) + 1);
case NOTATION_JANGGI:
return std::to_string(file_of(s) + 1);
case NOTATION_XIANGQI_WXF:
return std::to_string((pos.side_to_move() == WHITE ? pos.max_file() - file_of(s) : file_of(s)) + 1);
case NOTATION_THAI_SAN:
case NOTATION_THAI_LAN:
return THAI_FILES[file_of(s)];
default:
return std::string(1, char('a' + file_of(s)));
}
}
inline std::string rank(const Position& pos, Square s, Notation n) {
switch (n)
{
case NOTATION_SHOGI_HOSKING:
case NOTATION_SHOGI_HODGES_NUMBER:
return std::to_string(pos.max_rank() - rank_of(s) + 1);
case NOTATION_SHOGI_HODGES:
return std::string(1, char('a' + pos.max_rank() - rank_of(s)));
case NOTATION_JANGGI:
return std::to_string((pos.max_rank() - rank_of(s) + 1) % 10);
case NOTATION_XIANGQI_WXF:
{
if (pos.empty(s))
// Handle piece drops
return std::to_string(relative_rank(pos.side_to_move(), s, pos.max_rank()) + 1);
else if (pos.pieces(pos.side_to_move(), type_of(pos.piece_on(s))) & forward_file_bb(pos.side_to_move(), s))
return "-";
else
return "+";
}
case NOTATION_THAI_SAN:
case NOTATION_THAI_LAN:
return THAI_RANKS[rank_of(s)];
default:
return std::to_string(rank_of(s) + 1);
}
}
inline std::string square(const Position& pos, Square s, Notation n) {
switch (n)
{
case NOTATION_JANGGI:
return rank(pos, s, n) + file(pos, s, n);
default:
return file(pos, s, n) + rank(pos, s, n);
}
}
inline Disambiguation disambiguation_level(const Position& pos, Move m, Notation n) {
// Drops never need disambiguation
if (type_of(m) == DROP)
return NO_DISAMBIGUATION;
// NOTATION_LAN and Janggi always use disambiguation
if (n == NOTATION_LAN || n == NOTATION_THAI_LAN || n == NOTATION_JANGGI)
return SQUARE_DISAMBIGUATION;
Color us = pos.side_to_move();
Square from = from_sq(m);
Square to = to_sq(m);
Piece pc = pos.moved_piece(m);
PieceType pt = type_of(pc);
// Xiangqi uses either file disambiguation or +/- if two pieces on file
if (n == NOTATION_XIANGQI_WXF)
{
// Disambiguate by rank (+/-) if target square of other piece is valid
if (popcount(pos.pieces(us, pt) & file_bb(from)) == 2 && !multi_tandem(pos.pieces(us, pt)))
{
Square otherFrom = lsb((pos.pieces(us, pt) & file_bb(from)) ^ from);
Square otherTo = otherFrom + Direction(to) - Direction(from);
if (is_ok(otherTo) && (pos.board_bb(us, pt) & otherTo))
return RANK_DISAMBIGUATION;
}
return FILE_DISAMBIGUATION;
}
// Pawn captures always use disambiguation
if ((n == NOTATION_SAN || n == NOTATION_THAI_SAN) && pt == PAWN)
{
if (pos.capture(m))
return FILE_DISAMBIGUATION;
if (type_of(m) == PROMOTION && from != to && pos.sittuyin_promotion())
return SQUARE_DISAMBIGUATION;
}
// A disambiguation occurs if we have more than one piece of type 'pt'
// that can reach 'to' with a legal move.
Bitboard b = pos.pieces(us, pt) ^ from;
Bitboard others = 0;
while (b)
{
Square s = pop_lsb(b);
// Construct a potential move with identical special move flags
// and only a different "from" square.
Move testMove = Move(m ^ make_move(from, to) ^ make_move(s, to));
if ( pos.pseudo_legal(testMove)
&& pos.legal(testMove)
&& !(is_shogi(n) && pos.unpromoted_piece_on(s) != pos.unpromoted_piece_on(from)))
others |= s;
}
if (!others)
return NO_DISAMBIGUATION;
else if (is_shogi(n))
return SQUARE_DISAMBIGUATION;
else if (!(others & file_bb(from)))
return FILE_DISAMBIGUATION;
else if (!(others & rank_bb(from)))
return RANK_DISAMBIGUATION;
else
return SQUARE_DISAMBIGUATION;
}
inline std::string disambiguation(const Position& pos, Square s, Notation n, Disambiguation d) {
switch (d)
{
case FILE_DISAMBIGUATION:
return file(pos, s, n);
case RANK_DISAMBIGUATION:
return rank(pos, s, n);
case SQUARE_DISAMBIGUATION:
return square(pos, s, n);
default:
assert(d == NO_DISAMBIGUATION);
return "";
}
}
inline const std::string move_to_san(Position& pos, Move m, Notation n) {
std::string san = "";
Color us = pos.side_to_move();
Square from = from_sq(m);
Square to = to_sq(m);
if (type_of(m) == CASTLING)
{
san = to > from ? "O-O" : "O-O-O";
if (is_gating(m))
{
san += std::string("/") + (char)toupper(pos.piece_to_char()[make_piece(us, gating_type(m))]);
san += square(pos, gating_square(m), n);
}
}
else
{
// Piece
san += piece(pos, m, n);
if (n == NOTATION_THAI_LAN)
san += " ";
// Origin square, disambiguation
Disambiguation d = disambiguation_level(pos, m, n);
san += disambiguation(pos, from, n, d);
// Separator/Operator
if (type_of(m) == DROP)
san += n == NOTATION_SHOGI_HOSKING ? '\'' : is_shogi(n) ? '*' : '@';
else if (n == NOTATION_XIANGQI_WXF)
{
if (rank_of(from) == rank_of(to))
san += '=';
else if (relative_rank(us, to, pos.max_rank()) > relative_rank(us, from, pos.max_rank()))
san += '+';
else
san += '-';
}
else if (pos.capture(m))
san += 'x';
else if (n == NOTATION_LAN || n == NOTATION_THAI_LAN || (is_shogi(n) && (n != NOTATION_SHOGI_HOSKING || d == SQUARE_DISAMBIGUATION)) || n == NOTATION_JANGGI || (n == NOTATION_THAI_SAN && type_of(pos.moved_piece(m)) != PAWN))
san += '-';
// Destination square
if (n == NOTATION_XIANGQI_WXF && type_of(m) != DROP)
san += file_of(to) == file_of(from) ? std::to_string(std::abs(rank_of(to) - rank_of(from))) : file(pos, to, n);
else
san += square(pos, to, n);
// Suffix
if (type_of(m) == PROMOTION)
san += std::string("=") + (char)toupper(pos.piece_to_char()[make_piece(us, promotion_type(m))]);
else if (type_of(m) == PIECE_PROMOTION)
san += is_shogi(n) ? std::string("+") : std::string("=") + (char)toupper(pos.piece_to_char()[make_piece(us, pos.promoted_piece_type(type_of(pos.moved_piece(m))))]);
else if (type_of(m) == PIECE_DEMOTION)
san += is_shogi(n) ? std::string("-") : std::string("=") + std::string(1, toupper(pos.piece_to_char()[pos.unpromoted_piece_on(from)]));
else if (type_of(m) == NORMAL && is_shogi(n) && pos.pseudo_legal(make<PIECE_PROMOTION>(from, to)))
san += std::string("=");
if (is_gating(m))
san += std::string("/") + (char)toupper(pos.piece_to_char()[make_piece(us, gating_type(m))]);
}
// Wall square
if (pos.walling())
san += "," + square(pos, gating_square(m), n);
// Check and checkmate
if (pos.gives_check(m) && !is_shogi(n) && n != NOTATION_XIANGQI_WXF)
{
StateInfo st;
pos.do_move(m, st);
san += MoveList<LEGAL>(pos).size() ? "+" : "#";
pos.undo_move(m);
}
return san;
}
} // namespace SAN
inline bool has_insufficient_material(Color c, const Position& pos) {
// Other win rules
if ( pos.captures_to_hand()
|| pos.count_in_hand(c, ALL_PIECES)
|| (pos.extinction_value() != VALUE_NONE && !pos.extinction_pseudo_royal())
|| (pos.flag_region(c) && pos.count(c, pos.flag_piece(c))))
return false;
// Restricted pieces
Bitboard restricted = pos.pieces(~c, KING);
// Atomic kings can not help checkmating
if (pos.extinction_pseudo_royal() && pos.blast_on_capture() && (pos.extinction_piece_types() & COMMONER))
restricted |= pos.pieces(c, COMMONER);
for (PieceSet ps = pos.piece_types(); ps;)
{
PieceType pt = pop_lsb(ps);
if (pt == KING || !(pos.board_bb(c, pt) & pos.board_bb(~c, KING)))
restricted |= pos.pieces(c, pt);
else if (is_custom(pt) && pos.count(c, pt) > 0)
// to be conservative, assume any custom piece has mating potential
return false;
}
// Mating pieces
for (PieceType pt : { ROOK, QUEEN, ARCHBISHOP, CHANCELLOR, SILVER, GOLD, COMMONER, CENTAUR })
if ((pos.pieces(c, pt) & ~restricted) || (pos.count(c, pos.promotion_pawn_type(c)) && (pos.promotion_piece_types(c) & pt)))
return false;
// Color-bound pieces
Bitboard colorbound = 0, unbound;
for (PieceType pt : { BISHOP, FERS, FERS_ALFIL, ALFIL, ELEPHANT })
colorbound |= pos.pieces(pt) & ~restricted;
unbound = pos.pieces() ^ restricted ^ colorbound;
if ((colorbound & pos.pieces(c)) && (((DarkSquares & colorbound) && (~DarkSquares & colorbound)) || unbound || pos.stalemate_value() != VALUE_DRAW || pos.check_counting() || pos.makpong()))
return false;
// Unbound pieces require one helper piece of either color
if ((pos.pieces(c) & unbound) && (popcount(pos.pieces() ^ restricted) >= 2 || pos.stalemate_value() != VALUE_DRAW || pos.check_counting() || pos.makpong()))
return false;
// Non-draw stalemate with lone custom king
if ( pos.stalemate_value() != VALUE_DRAW && pos.king_type() != KING
&& pos.pieces(c, KING) && (pos.board_bb(c, KING) & pos.board_bb(~c, KING)))
return false;
return true;
}
inline Bitboard checked(const Position& pos) {
return (pos.checkers() ? square_bb(pos.square<KING>(pos.side_to_move())) : Bitboard(0))
| (pos.extinction_pseudo_royal() ? pos.checked_pseudo_royals(pos.side_to_move()) : Bitboard(0));
}
namespace FEN {
enum FenValidation : int {
FEN_INVALID_COUNTING_RULE = -14,
FEN_INVALID_CHECK_COUNT = -13,
FEN_INVALID_NB_PARTS = -11,
FEN_INVALID_CHAR = -10,
FEN_TOUCHING_KINGS = -9,
FEN_INVALID_BOARD_GEOMETRY = -8,
FEN_INVALID_POCKET_INFO = -7,
FEN_INVALID_SIDE_TO_MOVE = -6,
FEN_INVALID_CASTLING_INFO = -5,
FEN_INVALID_EN_PASSANT_SQ = -4,
FEN_INVALID_NUMBER_OF_KINGS = -3,
FEN_INVALID_HALF_MOVE_COUNTER = -2,
FEN_INVALID_MOVE_COUNTER = -1,
FEN_EMPTY = 0,
FEN_OK = 1
};
enum Validation : int {
NOK,
OK
};
struct CharSquare {
int rowIdx;
int fileIdx;
CharSquare() : rowIdx(-1), fileIdx(-1) {}
CharSquare(int row, int file) : rowIdx(row), fileIdx(file) {}
};
inline bool operator==(const CharSquare& s1, const CharSquare& s2) {
return s1.rowIdx == s2.rowIdx && s1.fileIdx == s2.fileIdx;
}
inline bool operator!=(const CharSquare& s1, const CharSquare& s2) {
return !(s1 == s2);
}
inline int non_root_euclidian_distance(const CharSquare& s1, const CharSquare& s2) {
return pow(s1.rowIdx - s2.rowIdx, 2) + pow(s1.fileIdx - s2.fileIdx, 2);
}
class CharBoard {
private:
int nbRanks;
int nbFiles;
std::vector<char> board; // fill an array where the pieces are for later geometry checks
public:
CharBoard(int ranks, int files) : nbRanks(ranks), nbFiles(files) {
assert(nbFiles > 0 && nbRanks > 0);
board = std::vector<char>(nbRanks * nbFiles, ' ');
}
void set_piece(int rankIdx, int fileIdx, char c) {
board[rankIdx * nbFiles + fileIdx] = c;
}
char get_piece(int rowIdx, int fileIdx) const {
return board[rowIdx * nbFiles + fileIdx];
}
int get_nb_ranks() const {
return nbRanks;
}
int get_nb_files() const {
return nbFiles;
}
/// Returns the square of a given character
CharSquare get_square_for_piece(char piece) const {
CharSquare s;
for (int r = 0; r < nbRanks; ++r)
{
for (int c = 0; c < nbFiles; ++c)
{
if (get_piece(r, c) == piece)
{
s.rowIdx = r;
s.fileIdx = c;
return s;
}
}
}
return s;
}
/// Returns all square positions for a given piece
std::vector<CharSquare> get_squares_for_pieces(Color color, PieceSet ps, const std::string& pieceChars) const {
std::vector<CharSquare> squares;
size_t pcIdx;
for (int r = 0; r < nbRanks; ++r)
for (int c = 0; c < nbFiles; ++c)
if ((pcIdx = pieceChars.find(get_piece(r, c))) != std::string::npos && (ps & type_of(Piece(pcIdx))) && color_of(Piece(pcIdx)) == color)
squares.emplace_back(CharSquare(r, c));
return squares;
}
friend std::ostream& operator<<(std::ostream& os, const CharBoard& board);
};
inline std::ostream& operator<<(std::ostream& os, const CharBoard& board) {
for (int r = 0; r < board.nbRanks; ++r)
{
for (int c = 0; c < board.nbFiles; ++c)
os << "[" << board.get_piece(r, c) << "] ";
os << std::endl;
}
return os;
}
inline bool contains(const std::string& str, char c) {
return str.find(c) != std::string::npos;
}
inline bool in_any(const std::vector<std::string>& vec, char c) {
for (std::string str : vec)
if (contains(str, c))
return true;
return false;
}
inline Validation check_for_valid_characters(const std::string& firstFenPart, const std::string& validSpecialCharactersFirstField, const Variant* v) {
for (char c : firstFenPart)
{
if (!isdigit(c) && !in_any({v->pieceToChar, v->pieceToCharSynonyms, validSpecialCharactersFirstField}, c))
{
std::cerr << "Invalid piece character: '" << c << "'." << std::endl;
return NOK;
}
}
return OK;
}
inline std::vector<std::string> get_fen_parts(const std::string& fullFen, char delim) {
std::vector<std::string> fenParts;
std::string curPart;
std::stringstream ss(fullFen);
while (std::getline(ss, curPart, delim))
fenParts.emplace_back(curPart);
return fenParts;
}
/// fills the character board according to a given FEN string
inline Validation fill_char_board(CharBoard& board, const std::string& fenBoard, const std::string& validSpecialCharactersFirstField, const Variant* v) {
int rankIdx = 0;
int fileIdx = 0;
char prevChar = '?';
for (char c : fenBoard)
{
if (c == ' ' || c == '[')
break;
if (c == '*')
++fileIdx;
else if (isdigit(c))
{
fileIdx += c - '0';
// if we have multiple digits attached we can add multiples of 9 to compute the resulting number (e.g. -> 21 = 2 + 2 * 9 + 1)
if (isdigit(prevChar))
fileIdx += 9 * (prevChar - '0');
}
else if (c == '/')
{
++rankIdx;
if (fileIdx != board.get_nb_files())
{
std::cerr << "curRankWidth != nbFiles: " << fileIdx << " != " << board.get_nb_files() << std::endl;
return NOK;
}
if (rankIdx == board.get_nb_ranks())
break;
fileIdx = 0;
}
else if (!contains(validSpecialCharactersFirstField, c))
{ // normal piece
if (fileIdx == board.get_nb_files())
{
std::cerr << "File index: " << fileIdx << " for piece '" << c << "' exceeds maximum of allowed number of files: " << board.get_nb_files() << "." << std::endl;
return NOK;
}
board.set_piece(v->maxRank-rankIdx, fileIdx, c); // we mirror the rank index because the black pieces are given first in the FEN
++fileIdx;
}
prevChar = c;
}
if (v->pieceDrops)
{ // pockets can either be defined by [] or /
if (rankIdx+1 != board.get_nb_ranks() && rankIdx != board.get_nb_ranks())
{
std::cerr << "Invalid number of ranks. Expected: " << board.get_nb_ranks() << " Actual: " << rankIdx+1 << std::endl;
return NOK;
}
}
else
{
if (rankIdx+1 != board.get_nb_ranks())
{
std::cerr << "Invalid number of ranks. Expected: " << board.get_nb_ranks() << " Actual: " << rankIdx+1 << std::endl;
return NOK;
}
}
return OK;
}
inline Validation check_touching_kings(const CharBoard& board, const std::array<CharSquare, 2>& kingPositions) {
if (non_root_euclidian_distance(kingPositions[WHITE], kingPositions[BLACK]) <= 2)
{
std::cerr << "King pieces are next to each other." << std::endl;
std::cerr << board << std::endl;
return NOK;
}
return OK;
}
inline Validation fill_castling_info_splitted(const std::string& castlingInfo, std::array<std::string, 2>& castlingInfoSplitted) {
for (char c : castlingInfo)
{
if (c != '-')
{
if (!isalpha(c))
{
std::cerr << "Invalid castling specification: '" << c << "'." << std::endl;
return NOK;
}
else if (isupper(c))
castlingInfoSplitted[WHITE] += tolower(c);
else
castlingInfoSplitted[BLACK] += c;
}
}
return OK;
}
inline std::string color_to_string(Color c) {
switch (c)
{
case WHITE:
return "WHITE";
case BLACK:
return "BLACK";
case COLOR_NB:
return "COLOR_NB";
default:
return "INVALID_COLOR";
}
}
inline std::string castling_rights_to_string(CastlingRights castlingRights) {
switch (castlingRights)
{
case KING_SIDE:
return "KING_SIDE";
case QUEEN_SIDE:
return "QUEENS_SIDE";
case WHITE_OO:
return "WHITE_OO";
case WHITE_OOO:
return "WHITE_OOO";
case BLACK_OO:
return "BLACK_OO";
case BLACK_OOO:
return "BLACK_OOO";
case WHITE_CASTLING:
return "WHITE_CASTLING";
case BLACK_CASTLING:
return "BLACK_CASTLING";
case ANY_CASTLING:
return "ANY_CASTLING";
case CASTLING_RIGHT_NB:
return "CASTLING_RIGHT_NB";
default:
return "INVALID_CASTLING_RIGHTS";
}
}
inline Validation check_castling_rank(const std::array<std::string, 2>& castlingInfoSplitted, const CharBoard& board,
const std::array<CharSquare, 2>& kingPositions, const Variant* v) {
for (Color c : {WHITE, BLACK})
{
const Rank castlingRank = relative_rank(c, v->castlingRank, v->maxRank);
for (char castlingFlag : castlingInfoSplitted[c])
{
if (tolower(castlingFlag) == 'k' || tolower(castlingFlag) == 'q')
{
if (kingPositions[c].rowIdx != castlingRank)
{
std::cerr << "The " << color_to_string(c) << " king must be on rank " << castlingRank << " if castling is enabled for " << color_to_string(c) << "." << std::endl;
return NOK;
}
bool kingside = tolower(castlingFlag) == 'k';
bool castlingRook = false;
size_t pcIdx;
for (int f = kingside ? board.get_nb_files() - 1 : 0; f != kingPositions[c].fileIdx; kingside ? f-- : f++)
if ( (pcIdx = v->pieceToChar.find(board.get_piece(castlingRank, f))) != std::string::npos
&& (v->castlingRookPieces[c] & type_of(Piece(pcIdx)))
&& color_of(Piece(pcIdx)) == c)
{
castlingRook = true;
break;
}
if (!castlingRook)
{
std::cerr << "No castling rook for flag " << castlingFlag << std::endl;
return NOK;
}
}
else if (board.get_piece(castlingRank, tolower(castlingFlag) - 'a') == ' ')
{
std::cerr << "No gating piece for flag " << castlingFlag << std::endl;
return NOK;
}
}
}
return OK;
}
inline Validation check_standard_castling(std::array<std::string, 2>& castlingInfoSplitted, const CharBoard& board,
const std::array<CharSquare, 2>& kingPositions, const std::array<CharSquare, 2>& kingPositionsStart,
const std::array<std::vector<CharSquare>, 2>& rookPositionsStart, const Variant* v) {
for (Color c : {WHITE, BLACK})
{
if (castlingInfoSplitted[c].size() == 0)
continue;
if (kingPositions[c] != kingPositionsStart[c])
{
std::cerr << "The " << color_to_string(c) << " KING has moved. Castling is no longer valid for " << color_to_string(c) << "." << std::endl;
return NOK;
}
for (CastlingRights castling: {KING_SIDE, QUEEN_SIDE})
{
CharSquare rookStartingSquare = castling == QUEEN_SIDE ? rookPositionsStart[c][0] : rookPositionsStart[c][1];
char targetChar = castling == QUEEN_SIDE ? 'q' : 'k';
size_t pcIdx;
if (castlingInfoSplitted[c].find(targetChar) != std::string::npos)
{
if ( (pcIdx = v->pieceToChar.find(board.get_piece(rookStartingSquare.rowIdx, rookStartingSquare.fileIdx))) == std::string::npos
|| !(v->castlingRookPieces[c] & type_of(Piece(pcIdx)))
|| color_of(Piece(pcIdx)) != c)
{
std::cerr << "The " << color_to_string(c) << " ROOK on the "<< castling_rights_to_string(castling) << " has moved. "
<< castling_rights_to_string(castling) << " castling is no longer valid for " << color_to_string(c) << "." << std::endl;
return NOK;
}
}
}
}
return OK;
}
inline Validation check_pocket_info(const std::string& fenBoard, int nbRanks, const Variant* v, std::string& pocket) {
char stopChar;
int offset = 0;
if (std::count(fenBoard.begin(), fenBoard.end(), '/') == nbRanks)
{
// look for last '/'
stopChar = '/';
}
else if (std::count(fenBoard.begin(), fenBoard.end(), '[') == 1)
{
// pocket is defined as [ and ]
stopChar = '[';
offset = 1;
if (*(fenBoard.end()-1) != ']')
{
std::cerr << "Pocket specification does not end with ']'." << std::endl;
return NOK;
}
}
else
// allow to skip pocket
return OK;
// look for last '/'
for (auto it = fenBoard.rbegin()+offset; it != fenBoard.rend(); ++it)
{
const char c = *it;
if (c == stopChar)
return OK;
if (c != '-')
{
if (!in_any({v->pieceToChar, v->pieceToCharSynonyms}, c))
{
std::cerr << "Invalid pocket piece: '" << c << "'." << std::endl;
return NOK;
}
else
pocket += c;
}
}
std::cerr << "Pocket piece closing character '" << stopChar << "' was not found." << std::endl;
return NOK;
}
inline int piece_count(const std::string& fenBoard, Color c, PieceType pt, const Variant* v) {
return std::count(fenBoard.begin(), fenBoard.end(), v->pieceToChar[make_piece(c, pt)]);
}
inline Validation check_number_of_kings(const std::string& fenBoard, const std::string& startFenBoard, const Variant* v) {
int nbWhiteKings = piece_count(fenBoard, WHITE, KING, v);
int nbBlackKings = piece_count(fenBoard, BLACK, KING, v);
int nbWhiteKingsStart = piece_count(startFenBoard, WHITE, KING, v);
int nbBlackKingsStart = piece_count(startFenBoard, BLACK, KING, v);
if (nbWhiteKings > 1)
{
std::cerr << "Invalid number of white kings. Maximum: 1. Given: " << nbWhiteKings << std::endl;
return NOK;
}
if (nbBlackKings > 1)
{
std::cerr << "Invalid number of black kings. Maximum: 1. Given: " << nbBlackKings << std::endl;
return NOK;
}
if (nbWhiteKings != nbWhiteKingsStart)
{
std::cerr << "Invalid number of white kings. Expected: " << nbWhiteKingsStart << ". Given: " << nbWhiteKings << std::endl;
return NOK;
}
if (nbBlackKings != nbBlackKingsStart)
{
std::cerr << "Invalid number of black kings. Expected: " << nbBlackKingsStart << ". Given: " << nbBlackKings << std::endl;
return NOK;
}
return OK;
}
inline Validation check_en_passant_square(const std::string& enPassantInfo) {
if (enPassantInfo.size() != 1 || enPassantInfo[0] != '-')
{
if (enPassantInfo.size() != 2)
{
std::cerr << "Invalid en-passant square '" << enPassantInfo << "'. Expects 2 characters. Actual: " << enPassantInfo.size() << " character(s)." << std::endl;
return NOK;
}
if (!isalpha(enPassantInfo[0]))
{
std::cerr << "Invalid en-passant square '" << enPassantInfo << "'. Expects 1st character to be a letter." << std::endl;
return NOK;
}
if (!isdigit(enPassantInfo[1]))
{
std::cerr << "Invalid en-passant square '" << enPassantInfo << "'. Expects 2nd character to be a digit." << std::endl;
return NOK;
}
}
return OK;
}
inline Validation check_check_count(const std::string& checkCountInfo) {
if (checkCountInfo.size() != 3)
{
std::cerr << "Invalid check count '" << checkCountInfo << "'. Expects 3 characters. Actual: " << checkCountInfo.size() << " character(s)." << std::endl;
return NOK;
}
if (!isdigit(checkCountInfo[0]))
{
std::cerr << "Invalid check count '" << checkCountInfo << "'. Expects 1st character to be a digit." << std::endl;
return NOK;
}
if (!isdigit(checkCountInfo[2])) {
std::cerr << "Invalid check count '" << checkCountInfo << "'. Expects 3rd character to be a digit." << std::endl;
return NOK;
}
return OK;
}
inline Validation check_lichess_check_count(const std::string& checkCountInfo) {
if (checkCountInfo.size() != 4)
{
std::cerr << "Invalid check count '" << checkCountInfo << "'. Expects 4 characters. Actual: " << checkCountInfo.size() << " character(s)." << std::endl;
return NOK;
}
if (!isdigit(checkCountInfo[1]) || checkCountInfo[1] - '0' > 3)
{
std::cerr << "Invalid check count '" << checkCountInfo << "'. Expects 2nd character to be a digit up to 3." << std::endl;
return NOK;
}
if (!isdigit(checkCountInfo[3]) || checkCountInfo[3] - '0' > 3) {
std::cerr << "Invalid check count '" << checkCountInfo << "'. Expects 4th character to be a digit up to 3." << std::endl;
return NOK;
}
return OK;
}
inline Validation check_digit_field(const std::string& field) {
if (field.size() == 1 && field[0] == '-')
return OK;
for (char c : field)
if (!isdigit(c))
return NOK;
return OK;
}
inline std::string get_valid_special_chars(const Variant* v) {
std::string validSpecialCharactersFirstField = "/*";
// Whether or not '-', '+', '~', '[', ']' are valid depends on the variant being played.
if (v->shogiStylePromotions)
validSpecialCharactersFirstField += '+';
if (v->promotionPieceTypes[WHITE] || v->promotionPieceTypes[BLACK])
validSpecialCharactersFirstField += '~';
if (!v->freeDrops && (v->pieceDrops || v->seirawanGating))
validSpecialCharactersFirstField += "[-]";
return validSpecialCharactersFirstField;
}
inline FenValidation validate_fen(const std::string& fen, const Variant* v, bool chess960 = false) {
const std::string validSpecialCharactersFirstField = get_valid_special_chars(v);
// 0) Layout
// check for empty fen
if (fen.empty())
{
std::cerr << "Fen is empty." << std::endl;
return FEN_EMPTY;
}
std::vector<std::string> fenParts = get_fen_parts(fen, ' ');
std::vector<std::string> startFenParts = get_fen_parts(v->startFen, ' ');
// check for number of parts
const unsigned int maxNumberFenParts = 6 + v->checkCounting;
if (fenParts.size() < 1 || fenParts.size() > maxNumberFenParts)
{
std::cerr << "Invalid number of fen parts. Expected: >= 1 and <= " << maxNumberFenParts
<< " Actual: " << fenParts.size() << std::endl;
return FEN_INVALID_NB_PARTS;
}
// 1) Part
// check for valid characters
if (check_for_valid_characters(fenParts[0], validSpecialCharactersFirstField, v) == NOK)
return FEN_INVALID_CHAR;
// check for number of ranks
const int nbRanks = v->maxRank + 1;
// check for number of files
const int nbFiles = v->maxFile + 1;
CharBoard board(nbRanks, nbFiles); // create a 2D character board for later geometry checks
if (fill_char_board(board, fenParts[0], validSpecialCharactersFirstField, v) == NOK)
return FEN_INVALID_BOARD_GEOMETRY;
// check for pocket
std::string pocket = "";
if (v->pieceDrops || v->seirawanGating)
{
if (check_pocket_info(fenParts[0], nbRanks, v, pocket) == NOK)
return FEN_INVALID_POCKET_INFO;
}
// check for number of kings
if (v->pieceTypes & KING)
{
// we have a royal king in this variant,
// ensure that each side has exactly as many kings as in the starting position
// (variants like giveaway use the COMMONER piece type instead)
if (check_number_of_kings(fenParts[0], startFenParts[0], v) == NOK)
return FEN_INVALID_NUMBER_OF_KINGS;
// check for touching kings if there are exactly two royal kings on the board (excluding pocket)
if ( v->kingType == KING
&& piece_count(fenParts[0], WHITE, KING, v) - piece_count(pocket, WHITE, KING, v) == 1
&& piece_count(fenParts[0], BLACK, KING, v) - piece_count(pocket, BLACK, KING, v) == 1)
{
std::array<CharSquare, 2> kingPositions;
kingPositions[WHITE] = board.get_square_for_piece(v->pieceToChar[make_piece(WHITE, KING)]);
kingPositions[BLACK] = board.get_square_for_piece(v->pieceToChar[make_piece(BLACK, KING)]);
if (check_touching_kings(board, kingPositions) == NOK)
return FEN_TOUCHING_KINGS;
}
}
// 2) Part
// check side to move char
if (fenParts.size() >= 2 && fenParts[1][0] != 'w' && fenParts[1][0] != 'b')
{
std::cerr << "Invalid side to move specification: '" << fenParts[1][0] << "'." << std::endl;
return FEN_INVALID_SIDE_TO_MOVE;