- Ambiguity move_ambiguity(const Position& pos, Move m) {
-
- MoveStack mlist[MOVES_MAX], *last;
- Move candidates[8];
- Square from = move_from(m);
- Square to = move_to(m);
- Piece pc = pos.piece_on(from);
- int matches = 0, f = 0, r = 0;
-
- // If there is only one piece 'pc' then move cannot be ambiguous
- if (pos.piece_count(pos.side_to_move(), type_of_piece(pc)) == 1)
- return AMBIGUITY_NONE;
-
- // Collect all legal moves of piece 'pc' with destination 'to'
- last = generate<MV_LEGAL>(pos, mlist);
- for (MoveStack* cur = mlist; cur != last; cur++)
- if (move_to(cur->move) == to && pos.piece_on(move_from(cur->move)) == pc)
- candidates[matches++] = cur->move;
-
- if (matches == 1)
- return AMBIGUITY_NONE;
-
- for (int i = 0; i < matches; i++)
- {
- if (square_file(move_from(candidates[i])) == square_file(from))
- f++;
-
- if (square_rank(move_from(candidates[i])) == square_rank(from))
- r++;
- }
-
- return f == 1 ? AMBIGUITY_FILE : r == 1 ? AMBIGUITY_RANK : AMBIGUITY_BOTH;
- }
-
-