rcx_unpack

#!/usr/bin/env python

import pathlib
import sys
import rcx
import struct

infile = open(sys.argv[1], 'rb')
outdir = pathlib.Path(sys.argv[2])
outdir.mkdir(exist_ok=True)

rcx_header = bytearray(infile.read(1))
while rcx_header[-1:] != b'\f':
    rcx_header.extend(infile.read(1))

with open(outdir / 'rcx_header', 'w') as fp:
    fp.write(rcx_header.decode('ascii'))

def unpack_ipl(infile, index):
    header = infile.read(0x1000)
    segment_record_bytes, = struct.unpack('<H', header[0xe:0x10])
    assert segment_record_bytes == 3*0x24

    segments_found = []

    for i in range(3):
        base = 0x10 + 0x24*i
        segment_header = header[base:base+0x24]
        length, = struct.unpack('<L', segment_header[0xc:0x10])
        if length:
            segments_found.append(length)

    with open(outdir / ('ipl_%d_hdr' % index), 'wb') as fp:
        fp.write(header)
    for seg, length in enumerate(segments_found):
        with open(outdir / ('ipl_%d_seg%d' % (index, seg)), 'wb') as fp:
            fp.write(infile.read(length))

index = 0
while True:
    pos = infile.tell()
    signature = infile.read(9)
    if signature == b'':    # EOW
        break
    infile.seek(pos, 0)

    if signature != b'EPSON IPL':
        print("ERROR: unexpected data at offset 0x%x" % pos)
        sys.exit(1)

    unpack_ipl(infile, index)
    index += 1