Rename square_empty() to is_empty()

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/evaluate.cpp

@@ -614,7 +614,7 @@ Value do_evaluate(const Position& pos, Value& margin) {
                 Square d = pawn_push(Us) + (file_of(s) == FILE_A ? DELTA_E : DELTA_W);
                 if (pos.piece_on(s + d) == make_piece(Us, PAWN))
                 {
-                    if (!pos.square_empty(s + d + pawn_push(Us)))
+                    if (!pos.is_empty(s + d + pawn_push(Us)))
                         score -= 2*TrappedBishopA1H1Penalty;
                     else if (pos.piece_on(s + 2*d) == make_piece(Us, PAWN))
                         score -= TrappedBishopA1H1Penalty;
@@ -894,7 +894,7 @@ Value do_evaluate(const Position& pos, Value& margin) {
                 ebonus -= Value(square_distance(pos.king_square(Us), blockSq + pawn_push(Us)) * rr);
 
             // If the pawn is free to advance, increase bonus
-            if (pos.square_empty(blockSq))
+            if (pos.is_empty(blockSq))
             {
                 squaresToQueen = forward_bb(Us, s);
                 defendedSquares = squaresToQueen & ei.attackedBy[Us][0];

src/position.cpp

@@ -270,7 +270,7 @@ const string Position::to_fen() const {
       {
           sq = make_square(file, rank);
 
-          if (square_empty(sq))
+          if (is_empty(sq))
               emptyCnt++;
           else
           {
@@ -421,7 +421,7 @@ bool Position::move_attacks_square(Move m, Square s) const {
   Square to = to_sq(m);
   Piece piece = piece_moved(m);
 
-  assert(!square_empty(from));
+  assert(!is_empty(from));
 
   // Update occupancy as if the piece is moving
   occ = pieces() ^ from ^ to;
@@ -563,7 +563,7 @@ bool Position::is_pseudo_legal(const Move m) const {
       case DELTA_N:
       case DELTA_S:
       // Pawn push. The destination square must be empty.
-      if (!square_empty(to))
+      if (!is_empty(to))
           return false;
       break;
 
@@ -571,9 +571,9 @@ bool Position::is_pseudo_legal(const Move m) const {
       // Double white pawn push. The destination square must be on the fourth
       // rank, and both the destination square and the square between the
       // source and destination squares must be empty.
-      if (   rank_of(to) != RANK_4
+      if (    rank_of(to) != RANK_4
-          || !square_empty(to)
+          || !is_empty(to)
-          || !square_empty(from + DELTA_N))
+          || !is_empty(from + DELTA_N))
           return false;
       break;
 
@@ -581,9 +581,9 @@ bool Position::is_pseudo_legal(const Move m) const {
       // Double black pawn push. The destination square must be on the fifth
       // rank, and both the destination square and the square between the
       // source and destination squares must be empty.
-      if (   rank_of(to) != RANK_5
+      if (    rank_of(to) != RANK_5
-          || !square_empty(to)
+          || !is_empty(to)
-          || !square_empty(from + DELTA_S))
+          || !is_empty(from + DELTA_S))
           return false;
       break;
 
@@ -956,7 +956,7 @@ void Position::undo_move(Move m) {
   PieceType pt = type_of(piece);
   PieceType capture = st->capturedType;
 
-  assert(square_empty(from));
+  assert(is_empty(from));
   assert(color_of(piece) == us);
   assert(capture != KING);
 
@@ -1527,7 +1527,7 @@ void Position::flip() {
   startPosPly = pos.startpos_ply_counter();
 
   for (Square s = SQ_A1; s <= SQ_H8; s++)
-      if (!pos.square_empty(s))
+      if (!pos.is_empty(s))
           put_piece(Piece(pos.piece_on(s) ^ 8), ~s);
 
   if (pos.can_castle(WHITE_OO))

src/position.h

@@ -106,7 +106,7 @@ public:
   Piece piece_on(Square s) const;
   Square king_square(Color c) const;
   Square ep_square() const;
-  bool square_empty(Square s) const;
+  bool is_empty(Square s) const;
   const Square* piece_list(Color c, PieceType pt) const;
   int piece_count(Color c, PieceType pt) const;
 
@@ -249,7 +249,7 @@ inline Piece Position::piece_moved(Move m) const {
   return board[from_sq(m)];
 }
 
-inline bool Position::square_empty(Square s) const {
+inline bool Position::is_empty(Square s) const {
   return board[s] == NO_PIECE;
 }
 
@@ -416,14 +416,14 @@ inline bool Position::is_chess960() const {
 inline bool Position::is_capture_or_promotion(Move m) const {
 
   assert(is_ok(m));
-  return is_special(m) ? !is_castle(m) : !square_empty(to_sq(m));
+  return is_special(m) ? !is_castle(m) : !is_empty(to_sq(m));
 }
 
 inline bool Position::is_capture(Move m) const {
 
   // Note that castle is coded as "king captures the rook"
   assert(is_ok(m));
-  return (!square_empty(to_sq(m)) && !is_castle(m)) || is_enpassant(m);
+  return (!is_empty(to_sq(m)) && !is_castle(m)) || is_enpassant(m);
 }
 
 inline PieceType Position::captured_piece_type() const {