def deflate_long(n, add_sign_padding=True):
"""turns a long-int into a normalized byte string (adapted from Crypto.Util.number)"""
# after much testing, this algorithm was deemed to be the fastest
s = bytes()
n = long(n)
while (n != 0) and (n != -1):
s = struct.pack('>I', n & xffffffff) + s
n >>= 32
# strip off leading zeros, FFs
for i in enumerate(s):
if (n == 0) and (i[1] != deflate_zero):
break
if (n == -1) and (i[1] != deflate_ff):
break
else:
# degenerate case, n was either 0 or -1
i = (0,)
if n == 0:
s = zero_byte
else:
s = max_byte
s = s[i[0]:]
if add_sign_padding:
if (n == 0) and (byte_ord(s[0]) >= 0x80):
s = zero_byte + s
if (n == -1) and (byte_ord(s[0]) < 0x80):
s = max_byte + s
return s
def constant_time_bytes_eq(a, b):
if len(a) != len(b):
return False
res = 0
# noinspection PyUnresolvedReferences
for i in (xrange if PY2 else range)(len(a)):
res |= byte_ord(a[i]) ^ byte_ord(b[i])
return res == 0
def safe_string(s):
out = b('')
for c in s:
i = byte_ord(c)
if 32 <= i <= 127:
out += byte_chr(i)
else:
out += b('%%%02X' % i)
return out
def __call__(self):
"""Increament the counter and return the new value"""
i = self.blocksize - 1
while i > -1:
c = self.value[i] = byte_chr((byte_ord(self.value[i]) + 1) % 256)
if c != zero_byte:
return self.value.tostring()
i -= 1
# counter reset
x = deflate_long(self.overflow, add_sign_padding=False)
self.value = array.array('c', zero_byte * (self.blocksize - len(x)) + x)
return self.value.tostring()
def bit_length(n):
try:
return n.bitlength()
except AttributeError:
norm = deflate_long(n, False)
hbyte = byte_ord(norm[0])
if hbyte == 0:
return 1
bitlen = len(norm) * 8
while not (hbyte & 0x80):
hbyte <<= 1
bitlen -= 1
return bitlen
def inflate_long(s, always_positive=False):
"""turns a normalized byte string into a long-int (adapted from Crypto.Util.number)"""
out = long(0)
negative = 0
if not always_positive and (len(s) > 0) and (byte_ord(s[0]) >= 0x80):
negative = 1
if len(s) % 4:
filler = zero_byte
if negative:
filler = max_byte
# never convert this to ``s +=`` because this is a string, not a number
# noinspection PyAugmentAssignment
s = filler * (4 - len(s) % 4) + s
for i in range(0, len(s), 4):
out = (out << 32) + struct.unpack('>I', s[i:i+4])[0]
if negative:
out -= (long(1) << (8 * len(s)))
return out
def format_binary_line(data):
left = ' '.join(['%02X' % byte_ord(c) for c in data])
right = ''.join([('.%c..' % c)[(byte_ord(c)+63)//95] for c in data])
return '%-50s %s' % (left, right)
