s3dump_TXL

#!/usr/bin/python

import sys

def xor(u16):
    return 0x2000 ^ u16

with open(sys.argv[1]) as f:
    # check 6 byte signature and skip the following 16 bytes
    sig = f.read(6)
    if   sig == '\x01\x01\x01\x08\x02\01':
        print >> sys.stderr, "Found signature type 1 (native?)"
    elif sig == '\x01\x02\x01\x08\x02\01':
        print >> sys.stderr, "Found signature type 2 (akai?)"
    elif sig == '\x01\x02\x02\x08\x02\01':
        print >> sys.stderr, "Found signature type 3 (wave?)"
    else:
        print >> sys.stderr, "Signature mismatch"
        sys.exit(1)
    skip=f.read(16)
    if skip != '\x00' * 16:
        print >> sys.stderr, "Skipped bytes contain non-zero data", repr(skip)

    # read rest of file, do xor magic and scale to u16
    tmp = f.read(2)
    while len(tmp):
        u16 = (ord(tmp[0]) << 8) | ord(tmp[1])
        u16 = xor(u16)
        u16 <<= 2
        try:
            sys.stdout.write(chr(u16>>8))
            sys.stdout.write(chr(u16&0xff))
        except IOError, e:
            if    e.errno == 32: break
            else: raise
        tmp = f.read(2)