def decode_bittools(bseq):
""" Decompress Lempel-Ziv-Welch encoded sequence.
Parameters
----------
bseq : numpy.ndarray
Returns
-------
seq : str
See also
--------
encode_bittools
"""
init_invtable = [(code, chr(code)) for code in range(256)]
table = [chr(code) for code in range(256)] + ['CODECLEAR', 'CODEEOI']
table_append = table.append
table_len = table.__len__
bits = 9
max_code2 = (1 << bits) - 2
i = 0
seq = []
seq_append = seq.append
while True:
code, i = getword(bseq, i, bits)
if code == CODEEOI:
break
elif code == CODECLEAR:
del table[CODESTART:]
bits = 9
max_code2 = (1 << bits) - 2
code, i = getword(bseq, i, bits)
old_str = table[code]
seq_append(old_str)
old_code = code
else:
l = table_len()
if code < l:
s = table[code]
table_append(old_str + s[0])
old_str = s
else:
old_str = old_str + old_str[0]
table_append(old_str)
seq_append(old_str)
old_code = code
if l == max_code2:
bits += 1
max_code2 = (1 << bits) - 2
return ''.join(seq)
def decode_bittools(bseq):
""" Decompress Lempel-Ziv-Welch encoded sequence.
Parameters
----------
bseq : numpy.ndarray
Returns
-------
seq : str
See also
--------
encode_bittools
"""
init_invtable = [(code, chr(code)) for code in range (256)]
table = [chr(code) for code in range(256)] + ['CODECLEAR', 'CODEEOI']
table_append = table.append
table_len = table.__len__
bits = 9
max_code2 = (1<<bits) - 2
i = 0
seq = []
seq_append = seq.append
while True:
code, i = getword(bseq, i, bits)
if code==CODEEOI:
break
elif code==CODECLEAR:
del table[CODESTART:]
bits = 9
max_code2 = (1<<bits) - 2
code, i = getword(bseq, i, bits)
old_str = table[code]
seq_append(old_str)
old_code = code
else:
l = table_len()
if code < l:
s = table[code]
table_append(old_str + s[0])
old_str = s
else:
old_str = old_str + old_str[0]
table_append(old_str)
seq_append(old_str)
old_code = code
if l==max_code2:
bits += 1
max_code2 = (1<<bits) - 2
return ''.join(seq)
def test_wordbits ():
for width in range (1,64+1):
arr = numpy.array([131,17,235], dtype=numpy.int64)
arr2 = numpy.zeros((1+width//8), dtype=arr.dtype)
bstr = tobinary(arr)
word, next = bittools.getword(arr, 0, width)
if width > 7:
assert word==arr[0],repr((word, arr[0], bstr))
bittools.setword (arr2, 0, width, word)
assert bittools.getword (arr2, 0, width)[0]==word
assert tobinary(arr2)[:width] == bstr[:width],repr((tobinary(arr2)[:width], bstr[:width]))
def test_wordbits():
for width in range(1, 64 + 1):
arr = numpy.array([131, 17, 235], dtype=numpy.int64)
arr2 = numpy.zeros((1 + width // 8), dtype=arr.dtype)
bstr = tobinary(arr)
word, next = bittools.getword(arr, 0, width)
if width > 7:
assert word == arr[0], ` word, arr[0], bstr `
bittools.setword(arr2, 0, width, word)
assert bittools.getword(arr2, 0, width)[0] == word
assert tobinary(arr2)[:width] == bstr[:width], ` tobinary(
arr2)[:width], bstr[:width] `
def test_setgetword():
for dtype in [numpy.ubyte, numpy.int32, numpy.float64]:
arr = numpy.array(range(-256, 256), dtype=dtype)
arr2 = numpy.zeros(arr.shape, dtype=arr.dtype)
for i in range(arr.nbytes):
word, next = bittools.getword(arr, i * 8, 8)
bittools.setword(arr2, i * 8, 8, word)
assert (arr == arr2).all(), ` arr, arr2 `
print 'ok'
def test_setgetword():
for dtype in [numpy.ubyte, numpy.int32, numpy.float64]:
arr = numpy.array(list(range(-256,256)), dtype=dtype)
arr2 = numpy.zeros(arr.shape, dtype=arr.dtype)
for i in range (arr.nbytes):
word, next = bittools.getword (arr,i*8,8)
bittools.setword (arr2,i*8,8,word)
assert (arr==arr2).all(),repr((arr,arr2))
print('ok')
