dir2dir.ts

#!/usr/bin/env ts-node

import { readFileSync, writeFileSync } from "fs";

function UTF8ToString(array: Uint8Array) {
  let length = 0; while (length < array.length && array[length]) length++;
  return new TextDecoder().decode(array.subarray(0, length));
}

interface Asset {
  offset: number;
  size: number;
  name: string;
}

function loadDIR(buf: ArrayBuffer) {
  let assets = [] as Asset[];
  let view = new DataView(buf);
  for (let i = 0; i < buf.byteLength; i += 32) {
    let offset = view.getUint32(i + 0, true);
    let size   = view.getUint32(i + 4, true);
    let name = UTF8ToString(new Uint8Array(buf, i + 8, 24));
    assets.push({ offset, size, name });
  }
  return assets;
}

function loadAsset(img: ArrayBuffer, asset: Asset) {
  return img.slice(2048 * asset.offset, 2048 * (asset.offset + asset.size));
}

const base = process.argv[2];
const assets = loadDIR(readFileSync(base + ".dir").buffer);
const img = readFileSync(base + ".img").buffer;
for (const asset of assets) {
  const name = asset.name.toLowerCase();
  writeFileSync(name, Buffer.from(loadAsset(img, asset)));
  console.log("Saved", name);
}