def test_cache(self):
c = GenericCRC(polynomial="16_standard",
start_value=False,
final_xor=False,
reverse_polynomial=False,
reverse_all=False,
lsb_first=False,
little_endian=False)
c.calculate_cache(8)
self.assertEqual(len(c.cache), 256)
def test_different_crcs_fast(self):
c = GenericCRC(polynomial="16_standard",
start_value=False,
final_xor=False,
reverse_polynomial=False,
reverse_all=False,
lsb_first=False,
little_endian=False)
bitstring_set = [
"10101010", "00000001", "000000010", "000000011",
"0000000100000001",
"101001001010101010101011101111111000000000000111101010011101011",
"101001001010101101111010110111101010010110111010",
"00000000000000000000000000000000100000000000000000000000000000000001111111111111",
"1111111111111111111111111111111110111111111111111111110111111111111111110000000000"
"1"
]
for j in c.DEFAULT_POLYNOMIALS:
c.polynomial = c.choose_polynomial(j)
for i in bitstring_set:
for cache in [8, 4, 7, 12, 16]:
c.calculate_cache(cache)
# Standard
crc_new = c.cached_crc(c.str2bit(i))
crc_old = c.reference_crc(c.str2bit(i))
self.assertEqual(crc_old, crc_new)
# Special final xor
c.final_xor = c.str2bit("0000111100001111")
crc_new = c.cached_crc(c.str2bit(i))
crc_old = c.reference_crc(c.str2bit(i))
self.assertEqual(crc_old, crc_new)
c.final_xor = [False] * 16
# Special start value
c.start_value = c.str2bit("1010101010101010")
crc_new = c.cached_crc(c.str2bit(i))
crc_old = c.reference_crc(c.str2bit(i))
self.assertEqual(crc_old, crc_new)
c.start_value = [False] * 16
# little_endian
c.little_endian = True
crc_new = c.cached_crc(c.str2bit(i))
crc_old = c.reference_crc(c.str2bit(i))
self.assertEqual(crc_old, crc_new)
c.little_endian = False
# reverse all
c.reverse_all = True
crc_new = c.cached_crc(c.str2bit(i))
crc_old = c.reference_crc(c.str2bit(i))
self.assertEqual(crc_old, crc_new)
c.reverse_all = False
# reverse_polynomial
# We need to clear the cache before and after
c.cache = []
#
c.reverse_polynomial = True
crc_new = c.cached_crc(c.str2bit(i))
crc_old = c.reference_crc(c.str2bit(i))
self.assertEqual(crc_old, crc_new)
c.reverse_polynomial = False
#
c.cache = []
# TODO: Does only work for cachesize = 8
# lsb_first
c.calculate_cache(8)
c.lsb_first = True
crc_new = c.cached_crc(c.str2bit(i))
crc_old = c.reference_crc(c.str2bit(i))
self.assertEqual(crc_old, crc_new)
c.lsb_first = False