LZMA add uncompressed size

gistfile1.py

import mmap
import sys

with open(sys.argv[1], "r+b") as f:
	# memory-map the file, size 0 means whole file
	mm = mmap.mmap(f.fileno(), 0)
	offset = int(sys.argv[2])
	mm[offset:]

	f2 = sys.stdout
	
	f2.write(mm[offset:offset+5])
	uncompressed_size = '\x00\x00\x00\x10\x00\x00\x00\x00'
	f2.write(uncompressed_size)
	f2.write(mm[offset+5:])