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mcostalbamcostalba
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Assorted formatting and comment tweaks in position.h
No functional change.
1 parent b73ae56 commit aea2fde

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3 files changed

+60
-68
lines changed

3 files changed

+60
-68
lines changed

‎src/endgame.cpp‎

Lines changed: 2 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -167,7 +167,8 @@ Value Endgame<KXK>::operator()(const Position& pos) const {
167167
if ( pos.count<QUEEN>(strongSide)
168168
|| pos.count<ROOK>(strongSide)
169169
||(pos.count<BISHOP>(strongSide) && pos.count<KNIGHT>(strongSide))
170-
|| pos.bishop_pair(strongSide))
170+
||(pos.count<BISHOP>(strongSide) > 1 && opposite_colors(pos.list<BISHOP>(strongSide)[0],
171+
pos.list<BISHOP>(strongSide)[1])))
171172
result += VALUE_KNOWN_WIN;
172173

173174
return strongSide == pos.side_to_move() ? result : -result;

‎src/position.cpp‎

Lines changed: 2 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -176,9 +176,8 @@ void Position::init() {
176176
}
177177

178178

179-
/// Position::operator=() creates a copy of 'pos'. We want the new born Position
180-
/// object to not depend on any external data so we detach state pointer from
181-
/// the source one.
179+
/// Position::operator=() creates a copy of 'pos' but detaching the state pointer
180+
/// from the source to be self-consistent and not depending on any external data.
182181

183182
Position& Position::operator=(const Position& pos) {
184183

‎src/position.h‎

Lines changed: 56 additions & 64 deletions
Original file line numberDiff line numberDiff line change
@@ -21,70 +21,75 @@
2121
#define POSITION_H_INCLUDED
2222

2323
#include <cassert>
24-
#include <cstddef>
24+
#include <cstddef> // For offsetof()
2525

2626
#include "bitboard.h"
2727
#include "types.h"
2828

29-
30-
/// The checkInfo struct is initialized at c'tor time and keeps info used
31-
/// to detect if a move gives check.
3229
class Position;
3330
struct Thread;
3431

32+
/// CheckInfo struct is initialized at c'tor time and keeps info used to detect
33+
/// if a move gives check.
34+
3535
struct CheckInfo {
3636

3737
explicit CheckInfo(const Position&);
3838

3939
Bitboard dcCandidates;
4040
Bitboard pinned;
4141
Bitboard checkSq[PIECE_TYPE_NB];
42-
Square ksq;
42+
Square ksq;
4343
};
4444

4545

46-
/// The StateInfo struct stores information needed to restore a Position
47-
/// object to its previous state when we retract a move. Whenever a move
48-
/// is made on the board (by calling Position::do_move), a StateInfo
49-
/// object must be passed as a parameter.
46+
/// StateInfo struct stores information needed to restore a Position object to
47+
/// its previous state when we retract a move. Whenever a move is made on the
48+
/// board (by calling Position::do_move), a StateInfo object must be passed.
5049

5150
struct StateInfo {
52-
Key pawnKey, materialKey;
53-
Value nonPawnMaterial[COLOR_NB];
54-
int castlingRights, rule50, pliesFromNull;
55-
Score psq;
51+
52+
// Copied when making a move
53+
Key pawnKey;
54+
Key materialKey;
55+
Value nonPawnMaterial[COLOR_NB];
56+
int castlingRights;
57+
int rule50;
58+
int pliesFromNull;
59+
Score psq;
5660
Square epSquare;
5761

58-
Key key;
59-
Bitboard checkersBB;
60-
PieceType capturedType;
62+
// Not copied when making a move
63+
Key key;
64+
Bitboard checkersBB;
65+
PieceType capturedType;
6166
StateInfo* previous;
6267
};
6368

6469

6570
/// When making a move the current StateInfo up to 'key' excluded is copied to
66-
/// the new one. Here we calculate the quad words (64bits) needed to be copied.
71+
/// the new one. Here we calculate the quad words (64 bit) needed to be copied.
6772
const size_t StateCopySize64 = offsetof(StateInfo, key) / sizeof(uint64_t) + 1;
6873

6974

70-
/// The Position class stores the information regarding the board representation
71-
/// like pieces, side to move, hash keys, castling info, etc. The most important
72-
/// methods are do_move() and undo_move(), used by the search to update node info
73-
/// when traversing the search tree.
75+
/// Position class stores information regarding the board representation as
76+
/// pieces, side to move, hash keys, castling info, etc. Important methods are
77+
/// do_move() and undo_move(), used by the search to update node info when
78+
/// traversing the search tree.
7479

7580
class Position {
7681

7782
friend std::ostream& operator<<(std::ostream&, const Position&);
7883

79-
// Disable the default copy constructor
80-
Position(const Position&);
84+
Position(const Position&); // Disable the default copy constructor
8185

8286
public:
83-
Position() {}
87+
static void init();
88+
89+
Position() {} // To define the global object RootPos
8490
Position(const Position& pos, Thread* th) { *this = pos; thisThread = th; }
8591
Position(const std::string& f, bool c960, Thread* th) { set(f, c960, th); }
86-
Position& operator=(const Position&);
87-
static void init();
92+
Position& operator=(const Position&); // To assign RootPos from UCI
8893

8994
// FEN string input/output
9095
void set(const std::string& fenStr, bool isChess960, Thread* th);
@@ -135,7 +140,6 @@ class Position {
135140
// Piece specific
136141
bool pawn_passed(Color c, Square s) const;
137142
bool pawn_on_7th(Color c) const;
138-
bool bishop_pair(Color c) const;
139143
bool opposite_bishops() const;
140144

141145
// Doing and undoing moves
@@ -153,12 +157,8 @@ class Position {
153157
Key key() const;
154158
Key key_after(Move m) const;
155159
Key exclusion_key() const;
156-
Key pawn_key() const;
157160
Key material_key() const;
158-
159-
// Incremental piece-square evaluation
160-
Score psq_score() const;
161-
Value non_pawn_material(Color c) const;
161+
Key pawn_key() const;
162162

163163
// Other properties of the position
164164
Color side_to_move() const;
@@ -170,6 +170,8 @@ class Position {
170170
void set_nodes_searched(uint64_t n);
171171
bool is_draw() const;
172172
int rule50_count() const;
173+
Score psq_score() const;
174+
Value non_pawn_material(Color c) const;
173175

174176
// Position consistency check, for debugging
175177
bool pos_is_ok(int* step = NULL) const;
@@ -181,23 +183,21 @@ class Position {
181183
void set_castling_right(Color c, Square rfrom);
182184
void set_state(StateInfo* si) const;
183185

184-
// Helper functions
186+
// Other helpers
185187
Bitboard check_blockers(Color c, Color kingColor) const;
186188
void put_piece(Square s, Color c, PieceType pt);
187189
void remove_piece(Square s, Color c, PieceType pt);
188190
void move_piece(Square from, Square to, Color c, PieceType pt);
189191
template<bool Do>
190192
void do_castling(Square from, Square& to, Square& rfrom, Square& rto);
191193

192-
// Board and pieces
194+
// Data members
193195
Piece board[SQUARE_NB];
194196
Bitboard byTypeBB[PIECE_TYPE_NB];
195197
Bitboard byColorBB[COLOR_NB];
196198
int pieceCount[COLOR_NB][PIECE_TYPE_NB];
197199
Square pieceList[COLOR_NB][PIECE_TYPE_NB][16];
198200
int index[SQUARE_NB];
199-
200-
// Other info
201201
int castlingRightsMask[SQUARE_NB];
202202
Square castlingRookSquare[CASTLING_RIGHT_NB];
203203
Bitboard castlingPath[CASTLING_RIGHT_NB];
@@ -210,12 +210,12 @@ class Position {
210210
bool chess960;
211211
};
212212

213-
inline uint64_t Position::nodes_searched() const {
214-
return nodes;
213+
inline Color Position::side_to_move() const {
214+
return sideToMove;
215215
}
216216

217-
inline void Position::set_nodes_searched(uint64_t n) {
218-
nodes = n;
217+
inline bool Position::empty(Square s) const {
218+
return board[s] == NO_PIECE;
219219
}
220220

221221
inline Piece Position::piece_on(Square s) const {
@@ -226,14 +226,6 @@ inline Piece Position::moved_piece(Move m) const {
226226
return board[from_sq(m)];
227227
}
228228

229-
inline bool Position::empty(Square s) const {
230-
return board[s] == NO_PIECE;
231-
}
232-
233-
inline Color Position::side_to_move() const {
234-
return sideToMove;
235-
}
236-
237229
inline Bitboard Position::pieces() const {
238230
return byTypeBB[ALL_PIECES];
239231
}
@@ -266,14 +258,14 @@ template<PieceType Pt> inline const Square* Position::list(Color c) const {
266258
return pieceList[c][Pt];
267259
}
268260

269-
inline Square Position::ep_square() const {
270-
return st->epSquare;
271-
}
272-
273261
inline Square Position::king_square(Color c) const {
274262
return pieceList[c][KING][0];
275263
}
276264

265+
inline Square Position::ep_square() const {
266+
return st->epSquare;
267+
}
268+
277269
inline int Position::can_castle(CastlingRight cr) const {
278270
return st->castlingRights & cr;
279271
}
@@ -292,7 +284,6 @@ inline Square Position::castling_rook_square(CastlingRight cr) const {
292284

293285
template<PieceType Pt>
294286
inline Bitboard Position::attacks_from(Square s) const {
295-
296287
return Pt == BISHOP || Pt == ROOK ? attacks_bb<Pt>(s, byTypeBB[ALL_PIECES])
297288
: Pt == QUEEN ? attacks_from<ROOK>(s) | attacks_from<BISHOP>(s)
298289
: StepAttacksBB[Pt][s];
@@ -360,19 +351,20 @@ inline int Position::rule50_count() const {
360351
return st->rule50;
361352
}
362353

363-
inline bool Position::opposite_bishops() const {
354+
inline uint64_t Position::nodes_searched() const {
355+
return nodes;
356+
}
357+
358+
inline void Position::set_nodes_searched(uint64_t n) {
359+
nodes = n;
360+
}
364361

362+
inline bool Position::opposite_bishops() const {
365363
return pieceCount[WHITE][BISHOP] == 1
366364
&& pieceCount[BLACK][BISHOP] == 1
367365
&& opposite_colors(pieceList[WHITE][BISHOP][0], pieceList[BLACK][BISHOP][0]);
368366
}
369367

370-
inline bool Position::bishop_pair(Color c) const {
371-
372-
return pieceCount[c][BISHOP] >= 2
373-
&& opposite_colors(pieceList[c][BISHOP][0], pieceList[c][BISHOP][1]);
374-
}
375-
376368
inline bool Position::pawn_on_7th(Color c) const {
377369
return pieces(c, PAWN) & rank_bb(relative_rank(c, RANK_7));
378370
}
@@ -389,7 +381,7 @@ inline bool Position::capture_or_promotion(Move m) const {
389381

390382
inline bool Position::capture(Move m) const {
391383

392-
// Note that castling is encoded as "king captures the rook"
384+
// Castling is encoded as "king captures the rook"
393385
assert(is_ok(m));
394386
return (!empty(to_sq(m)) && type_of(m) != CASTLING) || type_of(m) == ENPASSANT;
395387
}
@@ -415,8 +407,8 @@ inline void Position::put_piece(Square s, Color c, PieceType pt) {
415407

416408
inline void Position::move_piece(Square from, Square to, Color c, PieceType pt) {
417409

418-
// index[from] is not updated and becomes stale. This works as long
419-
// as index[] is accessed just by known occupied squares.
410+
// index[from] is not updated and becomes stale. This works as long as index[]
411+
// is accessed just by known occupied squares.
420412
Bitboard from_to_bb = SquareBB[from] ^ SquareBB[to];
421413
byTypeBB[ALL_PIECES] ^= from_to_bb;
422414
byTypeBB[pt] ^= from_to_bb;
@@ -436,7 +428,7 @@ inline void Position::remove_piece(Square s, Color c, PieceType pt) {
436428
byTypeBB[ALL_PIECES] ^= s;
437429
byTypeBB[pt] ^= s;
438430
byColorBB[c] ^= s;
439-
/* board[s] = NO_PIECE; */ // Not needed, will be overwritten by capturing
431+
/* board[s] = NO_PIECE; Not needed, overwritten by the capturing one */
440432
Square lastSquare = pieceList[c][pt][--pieceCount[c][pt]];
441433
index[lastSquare] = index[s];
442434
pieceList[c][pt][index[lastSquare]] = lastSquare;

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