Extract.py

import os
from tkinter import filedialog
import tkinter

def read_meta_data(file):
    metaFile = open(file,"r")
    first_lline = metaFile.readline().split("<")
    partCount = int(first_lline[0])
    normal_size = int(first_lline[1])
    final_size = int(first_lline[2])
    
    filesInfo = [info for info in metaFile]
    fileNames = [name.split("<")[0] for name in filesInfo]
    fileSizes = [int(name.split("<")[1]) for name in filesInfo]
    
    return (partCount ,normal_size ,final_size ,fileNames ,fileSizes)


# get meta files
root = tkinter.Tk()
root.withdraw()
meta_file = filedialog.askopenfilename()
meta_file = meta_file.replace("\\","/") ;
root.destroy()

#get part count ,files info
part_count,normal_size ,final_size ,files_names,file_sizes = read_meta_data(meta_file)

path = "/".join(meta_file.split("/")[0:-1])

#output path 
output_path = path + "/Extraced Files"
try:
    os.mkdir(output_path)
except:
    pass


def change_to_next_extract_file():
    global extract_file_no
    global extract_file_size
    global extract_file
    if extract_file_no+1 < len(files_names):
        extract_file_no += 1
        extract_file_size = file_sizes[extract_file_no]
        extract_file = open(output_path+"/"+files_names[extract_file_no],"wb")
    

extract_file_no = 0
extract_file_size = file_sizes[extract_file_no]
extract_file = open(output_path+"/"+files_names[extract_file_no],"wb")
extracted_size = 0
for part_no in range(1,part_count+1):
    part_file = "{0}/part-{1}.part".format(path ,part_no)
    part_file = open(part_file,"rb")
    for content in part_file:
        while content:
            if extracted_size + len(content) <= extract_file_size :
                extract_file.write(content)
                extracted_size += len(content)
                if extracted_size == extract_file_size :
                    extracted_size = 0
                    extract_file.close()
                    change_to_next_extract_file()
                content = ""
            else:
                content_left = content[extract_file_size-extracted_size:]
                content = content[0:extract_file_size-extracted_size]
                extract_file.write(content)
                extract_file.close()
                content = content_left
                extracted_size = 0
                change_to_next_extract_file()
    part_file.close()
if not extract_file.closed:
    extract_file.close()