along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
+#include <algorithm>
#include <cassert>
#include <cstring>
#include <iomanip>
#include <iostream>
#include <sstream>
-#include <algorithm>
#include "bitcount.h"
#include "movegen.h"
startState.epSquare = SQ_NONE;
st = &startState;
- for (int i = 0; i < 8; i++)
+ for (int i = 0; i < PIECE_TYPE_NB; i++)
for (int j = 0; j < 16; j++)
- pieceList[0][i][j] = pieceList[1][i][j] = SQ_NONE;
+ pieceList[WHITE][i][j] = pieceList[BLACK][i][j] = SQ_NONE;
}
/// game and the endgame. These functions are used to initialize the incremental
/// scores when a new position is set up, and to verify that the scores are correctly
/// updated by do_move and undo_move when the program is running in debug mode.
+
Score Position::compute_psq_score() const {
Score score = SCORE_ZERO;
}
-/// Position::is_draw() tests whether the position is drawn by material,
-/// repetition, or the 50 moves rule. It does not detect stalemates, this
-/// must be done by the search.
-bool Position::is_draw() const {
+/// Position::is_draw() tests whether the position is drawn by 50 moves rule
+/// or by repetition. It does not detect stalemates.
- // Draw by material?
- if ( !pieces(PAWN)
- && (non_pawn_material(WHITE) + non_pawn_material(BLACK) <= BishopValueMg))
- return true;
+bool Position::is_draw() const {
- // Draw by the 50 moves rule?
if (st->rule50 > 99 && (!checkers() || MoveList<LEGAL>(*this).size()))
return true;
- // Draw by repetition?
int i = 4, e = std::min(st->rule50, st->pliesFromNull);
if (i <= e)
stp = stp->previous->previous;
if (stp->key == st->key)
- return true;
+ return true; // Draw after first repetition
i += 2;
/// Position::flip() flips position with the white and black sides reversed. This
/// is only useful for debugging especially for finding evaluation symmetry bugs.
+static char toggle_case(char c) {
+ return char(islower(c) ? toupper(c) : tolower(c));
+}
+
void Position::flip() {
- const Position pos(*this);
+ string f, token;
+ std::stringstream ss(fen());
- clear();
+ for (Rank rank = RANK_8; rank >= RANK_1; rank--) // Piece placement
+ {
+ std::getline(ss, token, rank > RANK_1 ? '/' : ' ');
+ f.insert(0, token + (f.empty() ? " " : "/"));
+ }
- sideToMove = ~pos.side_to_move();
- thisThread = pos.this_thread();
- nodes = pos.nodes_searched();
- chess960 = pos.is_chess960();
- gamePly = pos.game_ply();
+ ss >> token; // Active color
+ f += (token == "w" ? "B " : "W "); // Will be lowercased later
- for (Square s = SQ_A1; s <= SQ_H8; s++)
- if (!pos.is_empty(s))
- {
- Piece p = Piece(pos.piece_on(s) ^ 8);
- put_piece(~s, color_of(p), type_of(p));
- }
+ ss >> token; // Castling availability
+ f += token + " ";
- if (pos.can_castle(WHITE_OO))
- set_castle_right(BLACK, ~pos.castle_rook_square(WHITE, KING_SIDE));
- if (pos.can_castle(WHITE_OOO))
- set_castle_right(BLACK, ~pos.castle_rook_square(WHITE, QUEEN_SIDE));
- if (pos.can_castle(BLACK_OO))
- set_castle_right(WHITE, ~pos.castle_rook_square(BLACK, KING_SIDE));
- if (pos.can_castle(BLACK_OOO))
- set_castle_right(WHITE, ~pos.castle_rook_square(BLACK, QUEEN_SIDE));
+ std::transform(f.begin(), f.end(), f.begin(), toggle_case);
- if (pos.st->epSquare != SQ_NONE)
- st->epSquare = ~pos.st->epSquare;
+ ss >> token; // En passant square
+ f += (token == "-" ? token : token.replace(1, 1, token[1] == '3' ? "6" : "3"));
- st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove);
+ std::getline(ss, token); // Half and full moves
+ f += token;
- st->key = compute_key();
- st->pawnKey = compute_pawn_key();
- st->materialKey = compute_material_key();
- st->psq = compute_psq_score();
- st->npMaterial[WHITE] = compute_non_pawn_material(WHITE);
- st->npMaterial[BLACK] = compute_non_pawn_material(BLACK);
+ set(f, is_chess960(), this_thread());
assert(pos_is_ok());
}