CPS2 Utils

CPS2 Utils is a package for working with CPS2 ROMs in the MAME format in a browser. It supports unzipping, validating, decrypting, encrypting, patching with MiSTer .mra files, and more.

Usage

Installation

npm i cps2-utils

Working with a MAME ROM

cps2-utils exposes a few classes for working with ROMs generally, but the main one you'll be using is Cps2Rom. It contains interfaces to functionality such as decryption, combining binary files, patching, and more.

To instantiate a Cps2Rom, supply it with the MAME ROM .zip and then invoke read(). It's probably a good idea to invoke processExecutable() after that, which will give you access to patching, decryption, etc.

async getDecryptedRom(zipFile: File): Promise<Uint8Array> {
  const rom = await this.getRom(zipFile);
  await rom.decryptOpcodes();
  const decryptedOpcodes = rom.getDecryptedOpcodes();
  if (!(decryptedOpcodes && decryptedOpcodes.length)) {
    return Promise.reject('Something went wrong');
  }
  return Promise.resolve(decryptedOpcodes);
}

async getRom(zipFile: File): Promise<Cps2Rom> {
  const rom = new Cps2Rom(zipFile);
  await rom.read();
  await rom.processExecutable();
  return Promise.resolve(rom);
}

Cps2Rom also supports chaining its operations:

async getDecryptedRom(zipFile: File): Promise<Uint8Array> {
  const rom = await new Cps2Rom(zipFile).read();
  const decryptedOpcodes = (await rom.processExecutable()).getDecryptedOpcodes();
  if (!(decryptedOpcodes && decryptedOpcodes.length)) {
    return Promise.reject('Something went wrong');
  }
  return Promise.resolve(decryptedOpcodes);
}

Using a library like l8 to make the chains fluid is probably not the worst idea.

See DarkMrSoft for a concrete example of using this library.

Todo

• [x] Get graphics
• [ ] Decode graphics
• [ ] .ips to .mra
• [ ] .mra to .ips
• [x] Decrypt
  • [x] .zip
  • [x] .bin
• [ ] Encrypt
  • [ ] Files?
  • [x] Binary
• [ ] Swap bytes
  • [ ] Files?
  • [ ] Binary
• [x] Split binary to files ✅ 2023-07-15
• [ ] Graphics patching
• [ ] Audio patching
• [ ] Fill operation
• [ ] Continue operation