#!/usr/bin/python

import sys
import os

if len(sys.argv) < 2:
	sys.exit("Target file not specified")

f = open(sys.argv[1],"r+b")
f.seek(0,os.SEEK_END)

marker = "avcC"+chr(1)
mlen = len(marker)

sys.stdout.write("Searching");

found = 0
while found==0:
	if(f.tell()%50000==0):
		sys.stdout.write(".")
		sys.stdout.flush()
	f.seek(-mlen-1,os.SEEK_CUR)
	s=f.read(mlen)
	if s==marker:
		found=1
	elif f.tell()==mlen:
		f.close()
		sys.exit("\nCould not find file marker")

f.seek(2,os.SEEK_CUR)
f.write(chr(0x1F))
print "\nFile successfully patched"

f.close()