compress.py

import utils
import pathlib
import sys


def compress():
    name = ''
    raw = ''
    try:
        name = sys.argv[1]
        raw = open(name, "rb")
    except IndexError:
        print("Choose file you want to compress")
        exit()
    if pathlib.Path(name).suffix == ".hfcd":
        print("File compressed")
        exit()
    content = raw.read()
    counter = {}
    for item in content:
        letter = item.to_bytes(1, byteorder="big")
        if counter.get(letter) is None:
            counter[letter] = 1
        else:
            counter[letter] += 1

    node = utils.get_tree(counter)
    codes = node.get_dict()

    print(codes)
    print(counter)
    raw_size = len(content) * 8
    compressed_size = 0

    for key in codes:
        compressed_size += len(codes[key]) * counter[key]

    print(f"raw: {raw_size} compressed without header: {compressed_size}")
    empty_bits = (8 - compressed_size % 8) % 8
    print(empty_bits)

    utils.print_hashsum(content)

    output = open(f"{pathlib.Path(name)}.hfcd", "wb")

    output.write(empty_bits.to_bytes(1, byteorder="big"))
    output.write((len(counter) % 256).to_bytes(1, byteorder="big"))
    for key in counter:
        output.write(key)
        output.write(counter[key].to_bytes(4, byteorder="big"))

    buffer = "0" * empty_bits

    for letter in content:
        buffer += codes[letter.to_bytes(1, byteorder="big")]
        while len(buffer) >= 8:
            output.write(int(buffer[7::-1], 2).to_bytes(1, byteorder='big'))
            buffer = buffer[8:]

    raw.close()
    output.close()


if __name__ == '__main__':
    compress()