#include "position.h"
#include "psqtab.h"
#include "rkiss.h"
-#include "san.h"
#include "tt.h"
#include "ucioption.h"
A FEN string contains six fields. The separator between fields is a space. The fields are:
1) Piece placement (from white's perspective). Each rank is described, starting with rank 8 and ending
- with rank 1; within each rank, the contents of each square are described from file a through file h.
+ with rank 1; within each rank, the contents of each square are described from file A through file H.
Following the Standard Algebraic Notation (SAN), each piece is identified by a single letter taken
from the standard English names. White pieces are designated using upper-case letters ("PNBRQK")
while Black take lowercase ("pnbrqk"). Blank squares are noted using digits 1 through 8 (the number
*/
char token;
+ int hmc, fmn;
std::istringstream ss(fen);
- Rank rank = RANK_8;
- File file = FILE_A;
+ Square sq = SQ_A8;
clear();
// 1. Piece placement field
while (ss.get(token) && token != ' ')
{
- if (isdigit(token))
+ if (pieceLetters.find(token) != pieceLetters.end())
{
- file += File(token - '0'); // Skip the given number of files
- continue;
+ put_piece(pieceLetters[token], sq);
+ sq++;
}
+ else if (isdigit(token))
+ sq += Square(token - '0'); // Skip the given number of files
else if (token == '/')
- {
- file = FILE_A;
- rank--;
- continue;
- }
-
- if (pieceLetters.find(token) == pieceLetters.end())
+ sq -= SQ_A3; // Jump back of 2 rows
+ else
goto incorrect_fen;
-
- put_piece(pieceLetters[token], make_square(file, rank));
- file++;
}
// 2. Active color
// 3. Castling availability
while (ss.get(token) && token != ' ')
- {
- if (token == '-')
- continue;
-
if (!set_castling_rights(token))
goto incorrect_fen;
- }
- // 4. En passant square -- ignore if no capture is possible
+ // 4. En passant square
char col, row;
if ( (ss.get(col) && (col >= 'a' && col <= 'h'))
&& (ss.get(row) && (row == '3' || row == '6')))
{
- Square fenEpSquare = make_square(file_from_char(col), rank_from_char(row));
- Color them = opposite_color(sideToMove);
+ st->epSquare = make_square(file_from_char(col), rank_from_char(row));
- if (attacks_from<PAWN>(fenEpSquare, them) & pieces(PAWN, sideToMove))
- st->epSquare = fenEpSquare;
+ // Ignore if no capture is possible
+ Color them = opposite_color(sideToMove);
+ if (!(attacks_from<PAWN>(st->epSquare, them) & pieces(PAWN, sideToMove)))
+ st->epSquare = SQ_NONE;
}
- // 5-6. Halfmove clock and fullmove number are not parsed
+ // 5. Halfmove clock
+ if (ss >> hmc)
+ st->rule50 = hmc;
+
+ // 6. Fullmove number
+ if (ss >> fmn)
+ startPosPlyCounter = (fmn - 1) * 2 + int(sideToMove == BLACK);
// Various initialisations
castleRightsMask[make_square(initialKFile, RANK_1)] ^= WHITE_OO | WHITE_OOO;
initialKRFile = rookFile;
}
}
- else return false;
+ else
+ return token == '-';
return true;
}
}
+/// Position::do_setup_move() makes a permanent move on the board.
+/// It should be used when setting up a position on board.
+/// You can't undo the move.
+
+void Position::do_setup_move(Move m) {
+
+ StateInfo newSt;
+
+ do_move(m, newSt);
+
+ // Reset "game ply" in case we made a non-reversible move.
+ // "game ply" is used for repetition detection.
+ if (st->rule50 == 0)
+ st->gamePly = 0;
+
+ // Update the number of plies played from the starting position
+ startPosPlyCounter++;
+
+ // Our StateInfo newSt is about going out of scope so copy
+ // its content inside pos before it disappears.
+ detach();
+}
+
/// Position::do_move() makes a move, and saves all information necessary
/// to a StateInfo object. The move is assumed to be legal.
/// Pseudo-legal moves should be filtered out before this function is called.
assert(is_ok());
assert(move_is_ok(m));
+ assert(&newSt != st);
nodes++;
Key key = st->key;
Value npMaterial[2];
};
- if (&newSt != st)
- memcpy(&newSt, st, sizeof(ReducedStateInfo));
+ memcpy(&newSt, st, sizeof(ReducedStateInfo));
newSt.previous = st;
st = &newSt;
}
-/// Position::reset_game_ply() simply sets gamePly to 0. It is used from the
-/// UCI interface code, whenever a non-reversible move is made in a
-/// 'position fen <fen> moves m1 m2 ...' command. This makes it possible
-/// for the program to handle games of arbitrary length, as long as the GUI
-/// handles draws by the 50 move rule correctly.
-
-void Position::reset_game_ply() {
-
- st->gamePly = 0;
-}
-
-void Position::inc_startpos_ply_counter() {
-
- startPosPlyCounter++;
-}
-
/// Position::put_piece() puts a piece on the given square of the board,
/// updating the board array, pieces list, bitboards, and piece counts.
return true;
// Draw by the 50 moves rule?
- if (st->rule50 > 99 && (st->rule50 > 100 || !is_mate()))
+ if (st->rule50 > 99 && !is_mate())
return true;
// Draw by repetition?
bool Position::is_mate() const {
MoveStack moves[MOVES_MAX];
- return is_check() && generate_moves(*this, moves) == moves;
+ return is_check() && generate<MV_LEGAL>(*this, moves) == moves;
}
do_null_move(st1);
// Then generate pseudo-legal moves that could give check
- last = generate_non_capture_checks(*this, mlist);
- last = generate_captures(*this, last);
+ last = generate<MV_NON_CAPTURE_CHECK>(*this, mlist);
+ last = generate<MV_CAPTURE>(*this, last);
// Loop through the moves, and see if one of them gives mate
Bitboard pinned = pinned_pieces(sideToMove);