#### Lempel Ziv

```"""
One of the several implementations of Lempel–Ziv–Welch compression algorithm
https://en.wikipedia.org/wiki/Lempel%E2%80%93Ziv%E2%80%93Welch
"""

import math
import os
import sys

"""
Reads given file as bytes and returns them as a long string
"""
result = ""
try:
with open(file_path, "rb") as binary_file:
for dat in data:
curr_byte = f"{dat:08b}"
result += curr_byte
return result
except OSError:
print("File not accessible")
sys.exit()

lexicon: dict[str, str], curr_string: str, index: int, last_match_id: str
) -> None:
"""
Adds new strings (curr_string + "0",  curr_string + "1") to the lexicon
"""
lexicon.pop(curr_string)
lexicon[curr_string + "0"] = last_match_id

if math.log2(index).is_integer():
for curr_key in lexicon:
lexicon[curr_key] = "0" + lexicon[curr_key]

lexicon[curr_string + "1"] = bin(index)[2:]

def compress_data(data_bits: str) -> str:
"""
Compresses given data_bits using Lempel–Ziv–Welch compression algorithm
and returns the result as a string
"""
lexicon = {"0": "0", "1": "1"}
result, curr_string = "", ""
index = len(lexicon)

for i in range(len(data_bits)):
curr_string += data_bits[i]
if curr_string not in lexicon:
continue

last_match_id = lexicon[curr_string]
result += last_match_id
index += 1
curr_string = ""

while curr_string != "" and curr_string not in lexicon:
curr_string += "0"

if curr_string != "":
last_match_id = lexicon[curr_string]
result += last_match_id

return result

def add_file_length(source_path: str, compressed: str) -> str:
"""
Adds given file's length in front (using Elias  gamma coding) of the compressed
string
"""
file_length = os.path.getsize(source_path)
file_length_binary = bin(file_length)[2:]
length_length = len(file_length_binary)

return "0" * (length_length - 1) + file_length_binary + compressed

def write_file_binary(file_path: str, to_write: str) -> None:
"""
Writes given to_write string (should only consist of 0's and 1's) as bytes in the
file
"""
byte_length = 8
try:
with open(file_path, "wb") as opened_file:
result_byte_array = [
to_write[i : i + byte_length]
for i in range(0, len(to_write), byte_length)
]

if len(result_byte_array[-1]) % byte_length == 0:
result_byte_array.append("10000000")
else:
result_byte_array[-1] += "1" + "0" * (
byte_length - len(result_byte_array[-1]) - 1
)

for elem in result_byte_array:
opened_file.write(int(elem, 2).to_bytes(1, byteorder="big"))
except OSError:
print("File not accessible")
sys.exit()

def compress(source_path: str, destination_path: str) -> None:
"""
Reads source file, compresses it and writes the compressed result in destination
file
"""  