Python Luhn Implementation, Draft 2

gistfile1.py

import sys
	
def process_input(input_str):
	input_str = input_str[::-1]
	states = []
	index = 0
	mask = []
	toggle = {1:2, 2:1}
	m1 = 1
	# for each character, add it up
	for c in input_str:
		if not c.isdigit():
			continue
		num = int(c)
		m2 = m1
		m1 = toggle[m1]
		for i in range(len(states)):
			temp = num * m2
			for c2 in str(temp):
				states[i][0] += int(c2)
			states[i][1] += [index]
		m2 = toggle[m2]
		states.append([num, [index]])
		index += 1
		# check which indices work out
		check = len(states) - 14
		for i in range(check + 1):
			validate(states[i], mask)
		if len(states) >= 16: states.pop(0)
	
	# for every index that needs masking, mask it
	l = list(input_str)
	for i in mask:
		l[i+1] = 'X'
	input_str = ''.join(l)
	return ''.join(input_str[::-1])
	#return input_str


def validate(index, mask):
	if type(index[0]) == int:
		if ((index[0] % 10) == 0):
			mask += index[1]


if __name__ == "__main__":
	result = process_input(sys.stdin.readline())
	sys.stdout.write(result)
	sys.stdout.flush()