def __encode(self):
"""
Encodes the raw message with the supplied generators.
"""
tmp_msg = ""
for i in range(len(self.mesg)-self.k+1):
for g in self.gen_polys:
last = string_utils.str_dot(self.mesg[i:i+self.k], g[::-1]) # reverse g
tmp_msg+=last
return tmp_msg
def gen_lookup(self):
"""
Pre-computes the trellis transition information
"""
lookup_table = {}
for i in range(2**(self.k-1)): # for each node in the column
key = string_utils.int_to_bin_string(i, self.k)
transition_info = []
for i in ["0", "1"]: #for both possible message bits (1 or 0)
next_key = i + key[:-1]
parity_arr = [string_utils.str_dot(poly, i+key) for poly in self.gen_polys]
parity_bits = "".join(parity_arr)
transition_info.append((i, parity_bits, next_key)) #determine the parity bits and next node
lookup_table[key] = transition_info
return lookup_table