Fix bin unpacking (#25)

Author: ianfab

src/tools/sfen_packer.cpp

@@ -304,7 +304,11 @@ namespace Stockfish::Tools {
 
         // First the position of the ball
         for (auto c : Colors)
-            pos.board[from_variant_square(Square(stream.read_n_bit(7)), pos)] = make_piece(c, pos.nnue_king());
+        {
+            Square king_sq = from_variant_square(Square(stream.read_n_bit(7)), pos);
+            if (pos.nnue_king())
+                pos.board[king_sq] = make_piece(c, pos.nnue_king());
+        }
 
         // Piece placement
         for (Rank r = pos.max_rank(); r >= RANK_1; --r)
@@ -315,17 +319,17 @@ namespace Stockfish::Tools {
 
                 // it seems there are already balls
                 Piece pc;
-                if (type_of(pos.board[sq]) != pos.nnue_king())
-                {
-                    assert(pos.board[sq] == NO_PIECE);
-                    pc = packer.read_board_piece_from_stream(pos);
-                }
-                else
+                if (pos.nnue_king() && type_of(pos.board[sq]) == pos.nnue_king())
                 {
                     pc = pos.board[sq];
                     // put_piece() will catch ASSERT unless you remove it all.
                     pos.board[sq] = NO_PIECE;
                 }
+                else
+                {
+                    assert(pos.board[sq] == NO_PIECE);
+                    pc = packer.read_board_piece_from_stream(pos);
+                }
 
                 // There may be no pieces, so skip in that case.
                 if (pc == NO_PIECE)
@@ -338,6 +342,16 @@ namespace Stockfish::Tools {
             }
         }
 
+        // Hand pieces - read the counts for each color and piece type
+        for(auto c: Colors)
+            for (PieceSet ps = pos.piece_types(); ps;)
+            {
+                PieceType pt = pop_lsb(ps);
+                int count = stream.read_n_bit(DATA_SIZE > 512 ? 7 : 5);
+                for (int i = 0; i < count; ++i)
+                    pos.add_to_hand(make_piece(c, pt));
+            }
+
         // Castling availability.
         // TODO(someone): Support chess960.
         pos.st->castlingRights = 0;