def from_x88(cls, source, target, promotion=''):
if not cls._x88_moves:
raise ValueError
# try to use the cache
if not promotion:
return cls._x88_moves[(source, target)]
return Move(Square.from_x88(source), Square.from_x88(target), promotion)
def get_all(cls):
'''Yield all moves combinations that do not have promotion.'''
#FIXME add in promotion
for source in Square.get_all():
for target in Square.get_all():
if source != target:
move = cls(Square.from_x88(source.x88), Square.from_x88(target.x88))
yield(move)
def ep_square(self):
'''The possible en passant square if available.
http://en.wikipedia.org/wiki/En_passant
'''
if not self._ep:
return self.null
return Square.from_x88(self._ep)
def get_pseudo_legal_moves(self, source=None):
""":yield: Pseudo legal moves in the current position.
:param source: The source square to limit moves or None for
all possible moves.
"""
tomove = self.fen._to_move
for x88 in [
x88 for x88 in Square._x88_squares.keys()
if self._pieces[x88] and Piece.color(self._pieces[x88]) ==
tomove and (source is None or x88 == source._x88)
]:
piece = self._pieces[x88]
klass = Piece.klass(piece)
# pawn moves
if klass == PAWN:
single, double, capleft, capright = X88.PAWN_OFFSETS[tomove]
# Single square ahead. Do not capture.
offset = x88 + single
if not self._pieces[offset]:
# Promotion.
if X88.is_backrank(offset, tomove):
for promote_to in Piece.promote_to:
yield Move.from_x88(x88, offset, promote_to)
else:
yield Move.from_x88(x88, offset)
# Two squares ahead. Do not capture.
if X88.is_secondrank(x88, tomove):
offset = x88 + double
if not self._pieces[offset]:
yield Move.from_x88(x88, offset)
# Pawn captures.
for cap in [capleft, capright]:
offset = x88 + cap
if offset & X88.X88:
continue
target = self._pieces[offset]
if target and Piece.color(target) != tomove:
# Promotion.
if X88.is_backrank(offset, tomove):
for promote_to in Piece.promote_to:
yield Move.from_x88(x88, offset, promote_to)
else:
yield Move.from_x88(x88, offset)
# En-passant.
elif not target and offset == self.fen._ep:
yield Move.from_x88(target, self.fen._ep)
#piece moves
else:
# for each a direction a piece moves in
for offset in X88.PIECE_OFFSETS[Piece.klass(piece)]:
t_x88 = x88 + offset
# while we do not fall off the board
while not t_x88 & 0x88:
# if there was not piece to attack then yield a quiet move
if not self._pieces[t_x88]:
yield Move.from_x88(x88, t_x88)
# do not break out
# else there is a piece there
else:
# if we can attack generate a move
if Piece.color(self._pieces[t_x88]) != tomove:
yield Move.from_x88(x88, t_x88)
# we hit something so break out
break
# Knight and king do not go multiple times in their direction.
if klass in [KNIGHT, KING]:
break
# travel down the board in the direction
t_x88 += offset
# castling moves
opponent = Piece.opposite_color(tomove)
ok = True
# get possible castling for the side to move
for castle in [
c for c in self.fen._castle_rights if Piece.color(c) == tomove
]:
(square, enum), _ = Piece.castle_squares[castle]
king = Square(square)
if Piece.klass(castle) == KING:
direc = 1
else:
direc = -1
# for offset in the squares the king will travel
for offset in range(0, 3):
s = Square.from_x88(king._x88 + (offset * direc))
# if we are not the king square and we are occuppied
if offset and self._pieces[s._x88]:
ok = False
break
# if we are trying to travel through check
if self.is_attacked(opponent, s):
ok = False
break
# kludge: we have to check occupancy for one more square on the queen side
if direc == -1 and self._pieces[s._x88 - 1]:
ok = False
if ok:
yield Move(king, s)
def target(self):
"""The target square."""
return Square.from_x88(self._target_x88)
def source(self):
"""The source square."""
return Square.from_x88(self._source_x88)
def get_pseudo_legal_moves(self, source=None):
""":yield: Pseudo legal moves in the current position.
:param source: The source square to limit moves or None for
all possible moves.
"""
tomove = self.fen._to_move
for x88 in [ x88 for x88 in Square._x88_squares.keys()
if self._pieces[x88]
and Piece.color(self._pieces[x88]) == tomove
and (source is None or x88 == source._x88)]:
piece = self._pieces[x88]
klass = Piece.klass(piece)
# pawn moves
if klass == PAWN:
single, double, capleft, capright = X88.PAWN_OFFSETS[tomove]
# Single square ahead. Do not capture.
offset = x88 + single
if not self._pieces[offset]:
# Promotion.
if X88.is_backrank(offset, tomove):
for promote_to in Piece.promote_to:
yield Move.from_x88(x88, offset, promote_to)
else:
yield Move.from_x88(x88, offset)
# Two squares ahead. Do not capture.
if X88.is_secondrank(x88, tomove):
offset = x88 + double
if not self._pieces[offset]:
yield Move.from_x88(x88, offset)
# Pawn captures.
for cap in [capleft, capright]:
offset = x88 + cap
if offset & X88.X88:
continue
target = self._pieces[offset]
if target and Piece.color(target) != tomove:
# Promotion.
if X88.is_backrank(offset, tomove):
for promote_to in Piece.promote_to:
yield Move.from_x88(x88, offset, promote_to)
else:
yield Move.from_x88(x88, offset)
# En-passant.
elif not target and offset == self.fen._ep:
yield Move.from_x88(target, self.fen._ep)
#piece moves
else:
# for each a direction a piece moves in
for offset in X88.PIECE_OFFSETS[Piece.klass(piece)]:
t_x88 = x88 + offset
# while we do not fall off the board
while not t_x88 & 0x88:
# if there was not piece to attack then yield a quiet move
if not self._pieces[t_x88]:
yield Move.from_x88(x88, t_x88)
# do not break out
# else there is a piece there
else:
# if we can attack generate a move
if Piece.color(self._pieces[t_x88]) != tomove:
yield Move.from_x88(x88, t_x88)
# we hit something so break out
break
# Knight and king do not go multiple times in their direction.
if klass in [KNIGHT, KING]:
break
# travel down the board in the direction
t_x88 += offset
# castling moves
opponent = Piece.opposite_color(tomove)
ok = True
# get possible castling for the side to move
for castle in [c for c in self.fen._castle_rights if Piece.color(c) == tomove]:
(square, enum), _ = Piece.castle_squares[castle]
king = Square(square)
if Piece.klass(castle) == KING:
direc = 1
else:
direc = -1
# for offset in the squares the king will travel
for offset in range(0, 3):
s = Square.from_x88(king._x88 + (offset * direc))
# if we are not the king square and we are occuppied
if offset and self._pieces[s._x88]:
ok = False
break
# if we are trying to travel through check
if self.is_attacked(opponent, s):
ok = False
break
# kludge: we have to check occupancy for one more square on the queen side
if direc == -1 and self._pieces[s._x88 - 1]:
ok = False
if ok:
yield Move(king, s)
def test_from_x88(self):
square = Square.from_x88(0)
self.assertEqual('a1', str(square))
