bz2stb.py - BZ2 Sprite Parser

"""This module provides a parser and writer for BZ2 .stb files and their plain text representations."""
VERSION = 1.0

import re
from ctypes import Structure, c_char, c_uint32, c_uint16

RE_TEXT_SPRITE = re.compile(r"^\s*\"(.*)\"\s+(\w+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+(\d+)\s+0x(\w+)")
RE_TEXT_FILE = re.compile(r"^\s*\@include \"(.+)\"")

ENCODING = "ascii"

class Sprite(Structure):
    _fields_ = [
        ("name", c_char*32), # Name used in ODF to refer to sprite
        ("file", c_char*8), # Texture image game slices the sprite from
        ("u", c_uint16), # x offset of sprite slice
        ("v", c_uint16), # y offset of sprite slice
        ("w", c_uint16), # Width of sprite slice
        ("h", c_uint16), # Height of sprite slice
        ("tw", c_uint16), # Texture width
        ("th", c_uint16), # Texture height
        ("flags", c_uint32)
    ]

    def decoded(self):
        return "\"%s\"\t\"%s\"\t%d\t%d\t%d\t%d\t%d\t%d\t0x%x" % (
                self.name.decode(encoding=ENCODING),
                self.file.decode(encoding=ENCODING),
                self.u, self.v,
                self.w, self.h,
                self.tw, self.th,
                self.flags
            )

class STB:
    def __init__(self, from_path=None):
        self.sprites = []

        if from_path:
            if from_path[-4::].casefold() == ".stb":
                self.read(from_path)
            else:
                self.read_text(from_path)

    def __bytes__(self):
        return b"".join(self.sprites)

    def read_text(self, path):
        with open(path, "r") as f:
            for line in f:
                match = RE_TEXT_FILE.match(line)
                if match:
                    # TODO: Check name against bz2-esque context of file locality? (files discoverable in a bzone.cfg context)
                    self.read_text(match.group(1)) # Will raise FileNotFoundError if not found.
                    continue

                match = RE_TEXT_SPRITE.match(line)
                if match:
                    sprite = Sprite()
                    sprite.name = match.group(1).encode(encoding=ENCODING)
                    sprite.file = match.group(2).encode(encoding=ENCODING)
                    sprite.u = int(match.group(3))
                    sprite.v = int(match.group(4))
                    sprite.w = int(match.group(5))
                    sprite.h = int(match.group(6))
                    sprite.tw = int(match.group(7))
                    sprite.th = int(match.group(8))
                    sprite.flags = int(match.group(9), 16)
                    self.sprites += [sprite]
                    continue

    def write_text(self, path):
        with open(path, "w") as f:
            f.write("sprite_tabel\n\n")
            for sprite in self.sprites:
                f.write(sprite.decoded() + "\n")

    def read(self, path):
        with open(path, "rb") as f:
            while True:
                sprite = Sprite()
                if not f.readinto(sprite):
                    break
                self.sprites += [sprite]

    def write(self, path):
        with open(path, "wb") as f:
            f.write(bytes(self))

    def show(self):
        print("sprite_tabel\n")
        for sprite in self.sprites:
            print(sprite.decoded())

if __name__ == "__main__":
    import sys, os
    for sprite_file in sys.argv[1::]:
        if sprite_file[-4::].casefold() == ".stb":
            # Convert STB file to humanly readable text file
            output_file = sprite_file + ".txt"
            if not os.path.exists(output_file):
                STB(sprite_file).write_text(output_file)

        else:
            # Convert sprite text file to STB file
            output_file = sprite_file + ".stb"
            if not os.path.exists(output_file):
                STB(sprite_file).write(output_file)