def __and__(self, other):
# heavy!
res = set()
for t1 in self.anf:
for t2 in other.anf:
res ^= {self._merge_products(t1, t2)}
return Bit(res)
def compute_anfs(bit):
if bit.is_input():
bit.meta["anf"] = Bit(bit.name())
return
if bit.is_const():
bit.meta["anf"] = Bit(bit.value())
return
TreeBit = bit.__class__
res = []
for sub in bit.args:
if isinstance(sub, TreeBit) and "anf" not in sub.meta:
compute_anfs(sub)
res.append(sub.meta["anf"])
bit.meta["anf"] = bit.OP.eval(bit.op, res)
def subs(self, lst):
if len(lst) == 0:
return self
if len(lst) > 1:
res = self.subs([lst[0]])
return res.subs(lst[1:])
var, bit = lst[0]
# print("subs", var, bit)
if isinstance(var, Bit):
var = var.var()
if isinstance(bit, int):
bit = Bit(bit)
assert isinstance(var, str)
assert isinstance(bit, Bit)
res = self.anf.copy()
for t1 in self.anf:
if var in t1:
res ^= {t1}
i = t1.index(var)
t1 = t1[:i] + t1[i + 1:]
for t2 in bit.anf:
res ^= {self._merge_products(t1, t2)}
return Bit(res)
def __xor__(self, other):
if not isinstance(other, Bit):
other = Bit(other)
return Bit(self.anf ^ other.anf)
def test_bit():
from cry.py.anf.symbolic import Bit
assert str(Bit(0)) == "0"
assert str(Bit(1)) == "1"
assert str(Bit("x1")) == "x1"
assert str(Bit("x2")) == "x2"
assert str(Bit("x1") & Bit("x2")) == "x1*x2"
assert str(Bit("x1") ^ Bit("x2")) == "x1 ^ x2"
assert str(
Bit(1) * Bit("x1") * Bit("x2") * Bit(1) + Bit(0) * Bit("x3") +
Bit(1)) == "1 ^ x1*x2"
ex = Bit("a") * Bit("b") + Bit("R") * Bit("b")
bb = Bit(1) + Bit("Q") + Bit("c") * Bit("b")
assert str(ex.subs([("b", bb)]) + 1) \
== "1 ^ Q*R ^ Q*a ^ R ^ R*b*c ^ a ^ a*b*c"
assert {Bit(0): 123}[0] == 123
def __eq__(self, other):
if isinstance(other, int) or isinstance(other, str):
return self == Bit(other)
assert isinstance(other, Bit)
return self.anf == other.anf
def is_var(self):
if len(self.anf) == 1:
for t in self.anf:
if len(t) == 1:
return True
return False
def var(self):
if len(self.anf) == 1:
for t in self.anf:
if len(t) == 1:
return t[0]
raise ValueError("Not a single variable!")
Bit.ZERO = Bit(0)
Bit.ONE = Bit(1)
def test_bit():
from cry.py.anf.symbolic import Bit
assert str(Bit(0)) == "0"
assert str(Bit(1)) == "1"
assert str(Bit("x1")) == "x1"
assert str(Bit("x2")) == "x2"
assert str(Bit("x1") & Bit("x2")) == "x1*x2"
assert str(Bit("x1") ^ Bit("x2")) == "x1 ^ x2"
assert str(
Bit(1) * Bit("x1") * Bit("x2") * Bit(1) + Bit(0) * Bit("x3") +
Bit(1)) == "1 ^ x1*x2"