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Rewrite flip() to use FEN string manipulation

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Instead of dealing directly with internal parameters
just "flip" the FEN string and set the position from
that.

No functional change.
This commit is contained in:
Marco Costalba
2013-08-05 11:06:23 +02:00
parent f31847302d
commit 23b6809f3d
1 changed files with 23 additions and 32 deletions
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53
src/position.cpp
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@@ -17,12 +17,12 @@
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"
@@ -1293,45 +1293,36 @@ bool Position::is_draw() const {
/// 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 isupper(c) ? tolower(c) : toupper(c);
}
void Position::flip() {
const Position pos(*this);
string f, token;
std::stringstream ss(fen());
clear();
sideToMove = ~pos.side_to_move();
thisThread = pos.this_thread();
nodes = pos.nodes_searched();
chess960 = pos.is_chess960();
gamePly = pos.game_ply();
for (Square s = SQ_A1; s <= SQ_H8; s++)
if (!pos.is_empty(s))
for (int i = 0; i < 8; i++)
{
Piece p = Piece(pos.piece_on(s) ^ 8);
put_piece(~s, color_of(p), type_of(p));
std::getline(ss, token, i < 7 ? '/' : ' ');
std::transform(token.begin(), token.end(), token.begin(), toggle_case);
f.insert(0, token + (i ? "/" : " "));
}
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));
ss >> token; // Side to move
f += (token == "w" ? "b " : "w ");
if (pos.st->epSquare != SQ_NONE)
st->epSquare = ~pos.st->epSquare;
ss >> token; // Castling flags
std::transform(token.begin(), token.end(), token.begin(), toggle_case);
f += token + " ";
st->checkersBB = attackers_to(king_square(sideToMove)) & pieces(~sideToMove);
ss >> token; // En-passant square
f += (token == "-" ? token : token.replace(1, 1, token[1] == '3' ? "6" : "3"));
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);
std::getline(ss, token); // Full and half moves
f += token;
set(f, is_chess960(), this_thread());
assert(pos_is_ok());
}