Pyython 2.6 compatible bit length.

This commit is contained in:
Andris Raugulis 2016-09-15 15:52:16 +03:00
parent 285d7280eb
commit d6980242ba
1 changed files with 22 additions and 10 deletions

View File

@ -172,7 +172,8 @@ class ReadBuf(object):
n = self.read_int() n = self.read_int()
return self.read(n) return self.read(n)
def _parse_mpint(self, v, pad, sf): @classmethod
def _parse_mpint(cls, v, pad, sf):
r = 0 r = 0
if len(v) % 4: if len(v) % 4:
v = pad * (4 - (len(v) % 4)) + v v = pad * (4 - (len(v) % 4)) + v
@ -225,27 +226,38 @@ class WriteBuf(object):
def write_list(self, v): def write_list(self, v):
self.write_string(u','.join(v)) self.write_string(u','.join(v))
def _create_mpint(self, v): @classmethod
length = v.bit_length() // 8 + (1 if v != 0 else 0) def _bitlength(cls, n):
try:
return n.bit_length()
except AttributeError:
return len(bin(n)) - (2 if n > 0 else 3)
@classmethod
def _create_mpint(cls, n, bits=None):
if bits is None:
bits = cls._bitlength(n)
length = bits // 8 + (1 if n != 0 else 0)
ql = (length + 7) // 8 ql = (length + 7) // 8
fmt, v2 = '>{0}Q'.format(ql), [b'\x00'] * ql fmt, v2 = '>{0}Q'.format(ql), [b'\x00'] * ql
for i in range(ql): for i in range(ql):
v2[ql - i - 1] = (v & 0xffffffffffffffff) v2[ql - i - 1] = (n & 0xffffffffffffffff)
v >>= 64 n >>= 64
data = bytes(struct.pack(fmt, *v2)[-length:]) data = bytes(struct.pack(fmt, *v2)[-length:])
if data.startswith(b'\xff\x80'): if data.startswith(b'\xff\x80'):
data = data[1:] data = data[1:]
return data return data
def write_mpint1(self, v): def write_mpint1(self, n):
# NOTE: Data Type Enc @ http://www.snailbook.com/docs/protocol-1.5.txt # NOTE: Data Type Enc @ http://www.snailbook.com/docs/protocol-1.5.txt
data = self._create_mpint(v) bits = self._bitlength(n)
self.write(struct.pack('>H', v.bit_length())) data = self._create_mpint(n, bits)
self.write(struct.pack('>H', bits))
return self.write(data) return self.write(data)
def write_mpint2(self, v): def write_mpint2(self, n):
# NOTE: Section 5 @ https://www.ietf.org/rfc/rfc4251.txt # NOTE: Section 5 @ https://www.ietf.org/rfc/rfc4251.txt
data = self._create_mpint(v) data = self._create_mpint(n)
return self.write_string(data) return self.write_string(data)
def write_flush(self): def write_flush(self):