decoder.py

# import sys
# import struct
# from sys import argv

import shutil
from struct import *

def Decompression(ipt, fileName):
    input_file = ipt
    n = 64
    maximum_table_size = pow(2,int(n))
    file = open(input_file, "rb")
    compressed_data = []
    next_code = 256
    decompressed_data = ""
    string = ""

    while True:
        rec = file.read(2)
        if len(rec) != 2:
            break
        (data, ) = unpack('>H', rec)
        compressed_data.append(data)

    dictionary_size = 256
    dictionary = dict([(x, chr(x)) for x in range(dictionary_size)])

    for code in compressed_data:
        if not (code in dictionary):
            dictionary[code] = string + (string[0])
        decompressed_data += dictionary[code]
        if not(len(string) == 0):
            dictionary[next_code] = string + (dictionary[code][0])
            next_code += 1
        string = dictionary[code]

    fileName = fileName.split(".")[0]
    output_file = open(fileName + "_decoded.txt", "w")
    for data in decompressed_data:
        output_file.write(data)
        
    output_file.close()
    file.close()

    # -- move to directory
    current_path = "./" + fileName + "_decoded.txt"
    new_path = "./decompressed/" + fileName + "_decoded.txt"

    shutil.move(current_path, new_path)

    return new_path