49 lines
1.7 KiB
Python
49 lines
1.7 KiB
Python
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"""Tools for parsing a ROE file."""
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from os import SEEK_CUR, SEEK_SET
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from os.path import basename, splitext
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from struct import unpack
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from .exceptions import InvalidROEFileError
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from .utils import nibble_flip
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class Roe:
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"""The DNA of an electronic fish with an embedded icon."""
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def __init__(self, name: str = "", author: str | None = None) -> None:
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self.name: str = name
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self.author: str | None = author
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self.is_mutant: bool = False
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self.unknowns: dict[str, bytes] = {}
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@classmethod
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def from_file(cls, filename: str) -> "Roe":
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"""Factory for importing roe from a .ROE file."""
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# Unlike .FSH files, the name comes from the filename itself. Since
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# DOS was limited to the 8.3 naming convention, a fish's name has a
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# forced limit of only eight characters.
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name = splitext(basename(filename))[0][0:8]
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roe = cls(name)
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with open(filename, "rb") as rfile:
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# First byte of file determines mutant status. Non-zero = mutant.
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# Second byte is padding.
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roe.is_mutant = unpack("?x", rfile.read(2))[0]
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# Next two bytes are unknown.
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roe.unknowns["00000002"] = unpack("2s", rfile.read(2))[0]
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# Next sixteen bytes is a nibble-flipped encoding of the original
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# author with a zero null termination byte.
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author = ""
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flipped_author = unpack("16s", rfile.read(16))[0]
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for letter in flipped_author:
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code = nibble_flip(letter)
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if code == 0:
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break
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author += chr(code)
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roe.author = author.upper()
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return roe
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