def decompress(compressed_data, c):
br = BitReader(compressed_data)
state = LzwState(c)
state.clear()
d = {}
htab = {}
output = []
output2 = []
while True:
if br.isEnd():
return []
cur_code = br.getBits(state.req_bits)
incode = cur_code
if cur_code == state.M_EOD:
break
if cur_code == state.M_CLR:
state.clear()
else:
if cur_code == state.next_code:
cur_code = state.oldcode
output.append(state.finchar)
while cur_code >= state.M_CLR:
if cur_code not in htab:
return []
output.append(htab[cur_code])
cur_code = d[cur_code + 1]
state.finchar = cur_code
while True:
output2.append(cur_code)
if not output:
break
cur_code = output.pop()
if state.next_code < 4096 and state.oldcode != -1:
d[state.next_code + 1] = state.oldcode
htab[state.next_code] = state.finchar
state.next_code += 1
if state.next_code >= state.next_shift:
if state.req_bits < 12:
state.req_bits += 1
state.next_shift = 1 << state.req_bits
state.oldcode = incode
return bytes(output2)
