def testReadCode(self):
"""
Tests that the interpretation of bit values performed by
``_readCode()`` as a contiguous bit-stream works as intended.
"""
inputs = bytearray(range(256))
d__ = LZWCodec.Decoder(inputs)
exp_output_stream = "".join(intToBitstring(b__) for b__ in inputs)
curr = 0
# TODO: this deserves to be an assignment expression.
code = d__._readCode()
while code != -1:
if curr + d__.bitspercode >= len(exp_output_stream):
exp_output = exp_output_stream[curr:] + "0" * (
(curr + d__.bitspercode) - len(exp_output_stream)
)
else:
exp_output = exp_output_stream[curr : curr + d__.bitspercode]
self.assertEqual(
exp_output,
intToBitstring(code, d__.bitspercode),
msg="(curr, code) = (%d, %d)" % (curr, code),
)
curr += d__.bitspercode
code = d__._readCode()
def testIntToBitstringToInt(self):
"""
Ensures that bitstringToInt(intToBitsring(input)) == input.
"""
inputs = range(2**12 + 1)
for i in inputs:
self.assertEqual(i, bitstringToInt(intToBitstring(i)))
def testWriteCode(self):
"""
Tests that the memorization of bit values performed by ``_writeCode()``
as a contiguous bit-stream works as intended.
"""
self.maxDiff = None
e__ = LZWCodec.Encoder("")
e__.output = list()
inputs = range(2 ** 8, 2 ** 12 - 1)
e__.bitspercode = int(floor(log(inputs[0], 2))) + 1
exp_output = "".join(intToBitstring(n__, floor(log(n__, 2))) for n__ in inputs)
for i in inputs:
if floor(log(i, 2)) + 1 > e__.bitspercode:
e__.bitspercode += 1
e__._writeCode(i)
self.assertEqual(
exp_output, "".join(intToBitstring(n__) for n__ in e__.output)[: e__.bitpos]
)
def testReadCode(self):
"""
Tests that the interpretation of bit values performed by
``_readCode()`` as a contiguous bit-stream works as intended.
"""
inputs = bytearray(range(256))
d = LZWCodec.Decoder(inputs)
expOutputStream = "".join(intToBitstring(b) for b in inputs)
curr = 0
code = d._readCode()
while code != -1:
if curr + d.bitspercode >= len(expOutputStream):
expOutput = expOutputStream[curr:]\
+ "0" * ((curr + d.bitspercode) - len(expOutputStream))
else:
expOutput = expOutputStream[curr:curr + d.bitspercode]
self.assertEqual(expOutput,
intToBitstring(code, d.bitspercode),
msg="(curr, code) = (%d, %d)" % (curr, code))
curr += d.bitspercode
code = d._readCode()