class _Amount:
def __init__(self, fraction_digits: int, precision: int):
self._ctx = Context(prec=precision, rounding=ROUND_HALF_EVEN)
self._fraction_digits = fraction_digits
self._precision = precision
self._quantizer = self._ctx.create_decimal(1).scaleb(-fraction_digits)
self._value = self._ctx.create_decimal(0)
def deserialize(self, serialized_value):
self._value = (
self._ctx.create_decimal(serialized_value)
.scaleb(-self._fraction_digits)
.quantize(self._quantizer)
)
return self
def serialize(self) -> int:
return int(self._value.scaleb(self._fraction_digits))
def set(self, value: Decimal):
self._value = self._ctx.create_decimal(value).quantize(self._quantizer)
return self
def clone(self):
raise NotImplementedError
def __str__(self):
return str(self._value)
def __imul__(self, other):
operand = other._value if isinstance(other, Amount) else other
value = self._ctx.multiply(self._value, operand)
return self.set(value)
def __itruediv__(self, other):
operand = other._value if isinstance(other, Amount) else other
value = self._ctx.divide(self._value, operand)
return self.set(value)
def __mul__(self, other):
return self.clone().__imul__(other)
def __truediv__(self, other):
return self.clone().__itruediv__(other)
def __iadd__(self, other):
operand = other._value if isinstance(other, Amount) else other
value = self._ctx.add(self._value, operand)
return self.set(value)
def __add__(self, other):
return self.clone().__iadd__(other)
return x
txt = open('../data/don_quixote.txt', 'r').read()
src = source(txt)
letters, count = map(list, zip(*src))
probs = [x / sum(count) for x in count]
p = min(probs)
k = ceil(-log(p, 2) + 2)
l = 1000
for _ in range(1000):
i = min(randrange(len(txt)), len(txt) - l)
str = txt[i:i + l]
c = arithmetic_encode(str, src, k)
print(c)
ctx = Context()
d = dict(zip(letters, probs))
pr = reduce(lambda x, y: ctx.multiply(x, Decimal(d[y])), str, Decimal(1))
expected_length = ceil(-ctx.divide(pr.ln(ctx), Decimal(2).ln(ctx))) + 1
actual_length = len(c)
assert (actual_length <= expected_length)
dec = arithmetic_decode(c, src, k, len(str))
print(dec)
assert (dec == str)
