57 lines
1.7 KiB
Python
57 lines
1.7 KiB
Python
# Eos - Verifiable elections
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# Copyright © 2017 RunasSudo (Yingtong Li)
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU Affero General Public License for more details.
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#
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# You should have received a copy of the GNU Affero General Public License
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# along with this program. If not, see <http://www.gnu.org/licenses/>.
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from eos.core.bigint import *
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from eos.core.objects import *
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class BitStream(EosObject):
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def __init__(self, value=None):
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if value:
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self.impl = value
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self.nbits = self.impl.nbits()
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else:
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self.impl = ZERO
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self.nbits = 0
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self.ptr = 0
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self.remaining = self.nbits
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def seek(self, ptr):
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self.ptr = ptr
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self.remaining = self.nbits - self.ptr
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def read(self, nbits):
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# 11000110110
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# ^----
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val = (self.impl >> (self.remaining - nbits)) & ((ONE << nbits) - ONE)
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self.ptr += nbits
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self.remaining -= nbits
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return val
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def write(self, bits):
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# 11 0100110
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# 10010
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# ^----
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self.impl = ((self.impl >> self.remaining) << (self.remaining + bits.nbits())) | (bits << self.remaining) | (self.impl & ((ONE << self.remaining) - 1))
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self.ptr += bits.nbits()
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self.nbits += bits.nbits()
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def serialise(self):
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return self.impl
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@classmethod
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def deserialise(cls, value):
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return cls(value)
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