#!/usr/bin/python3
# -*- coding: utf-8 -*-
"""
Compression with DEFLATE.
"""
import zlib
import struct
class Packer(object):
"""
You do not need to create instances of this class because compress and decompress are both static methods.
"""
@staticmethod
def compress(data):
"""
Compresses the given data with the DEFLATE algorithm. The first four bytes contain the length of the
uncompressed data.
:param data: uncompressed data
:type data: bytes or str
:return: compressed data
:rtype: bytes
"""
compress_object = zlib.compressobj(
zlib.Z_BEST_COMPRESSION,
zlib.DEFLATED,
zlib.MAX_WBITS,
zlib.DEF_MEM_LEVEL,
zlib.Z_DEFAULT_STRATEGY)
if type(data) == str:
compressed_data = compress_object.compress(data.encode('utf-8'))
compressed_data += compress_object.flush()
return struct.pack('!I', len(data.encode('utf-8'))) + compressed_data
elif type(data) == bytes:
compressed_data = compress_object.compress(data)
compressed_data += compress_object.flush()
return struct.pack('!I', len(data)) + compressed_data
else:
raise TypeError("Please pass a str or bytes to the packer.")
@staticmethod
def decompress(compressed_data):
"""
Decompresses the given data. Please be aware that the first four bytes are the length of the uncompressed
data.
:param compressed_data: compressed data
:type compressed_data: bytes
:return: uncompressed data
:rtype: bytes
"""
if type(compressed_data) == bytes:
try:
return zlib.decompress(compressed_data[4:])
except zlib.error:
raise ValueError("The compressed data is in a wrong format.")
else:
raise TypeError("Please pass bytes to the packer.")
