scnmod.py

import struct

header = struct.Struct("<5s58s256s256s6s")
playerinfo1 = struct.Struct("<64sH")
playerinfo2 = struct.Struct("<256s4I48s")

def modify_scn(filename, changes):
    with open(filename, "rb+") as scn:
        data = scn.read()

        offset = 0

        magic, unknown1, music_path, scenario_monitor_path, unknown2 = header.unpack_from(data, offset)

        assert magic == b"CHSCN"

        offset += header.size

        for i in range(15):
            # Need to read this in two parts, as struct does not handle length-prefixed
            # strings.

            name, desclen = playerinfo1.unpack_from(data, offset)
            offset += playerinfo1.size
            desc = data[offset:offset + desclen]
            offset += desclen

            skin_path, unknown3, start_lc, unknown4, start_qp, unknown5 = playerinfo2.unpack_from(data, offset)
            if start_lc > 0 and changes.start_lc is not None:
                start_lc = changes.start_lc
            if start_qp > 0 and changes.start_qp is not None:
                start_qp = changes.start_qp
            scn.seek(offset)
            scn.write(playerinfo2.pack(skin_path, unknown3, start_lc, unknown4, start_qp, unknown5))
            offset += playerinfo2.size

if __name__ == "__main__":
    from optparse import OptionParser

    parser = OptionParser(description="Modify information in Achron .scn files",
                          usage="usage: %prog [options] FILE [FILE ...]")
    parser.add_option("--start-lc", dest="start_lc", type="int",
                  help="set all the players' starting LC", metavar="LC")
    parser.add_option("--start-qp", dest="start_qp", type="int",
                  help="set all the players' starting QP", metavar="QP")

    options, args = parser.parse_args()

    for arg in args:
        modify_scn(arg, options)