def read_track(self, track_num): if track_num == 1: return self.track1 elif track_num == 2: return self.track2 elif track_num == 3: return self.track3 else: raise ValueError("Track must be 1, 2, or 3")

TRACK_MAX_LEN = 1: 79, 2: 40, 3: 107 class MagCard: def init (self): self.track1 = "" self.track2 = "" self.track3 = ""

#!/usr/bin/env python3 """ Magnetic Card Read/Write Utility (Simulated / Educational) Supports ISO 7811 tracks 1, 2, 3. """ import re import argparse TRACK1_CHARSET = set("ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789 .-+/$%*") TRACK2_CHARSET = set("0123456789:;<=>?") TRACK3_CHARSET = set("0123456789:;<=>?")

def clear(self): self.track1 = "" self.track2 = "" self.track3 = "" def encode_track(data, start_sentinel='%', end_sentinel='?'): """Adds start/end sentinels and LRC (simple XOR checksum)""" lrc = 0 for ch in data: lrc ^= ord(ch) checksum_char = chr(lrc % 128) # simple printable approximation return f"start_sentineldataend_sentinelchecksum_char"