README

gamearchive.js

This is a Javascript library that can read and write archive files used by a number of MS-DOS games from the 1990s. Archive files are like .zip files, except many games used their own custom file formats. This library is an attempt to provide a unified interface for reading and writing many of these formats.

Installation as an end-user

If you wish to use the command-line gamearch utility to work with game archives directly, you can install the library globally on your system:

npm install -g @malvineous/gamearchive

Command line interface

The gamearch utility can be used to manipulate archive files. Commands are specified one after the other as parameters. Use the --help option to get a list of all the available commands. Some quick examples:

# Copy a file out of an existing archive
gamearch open duke3d.grp extract stalker.mid

# Create a new archive
gamearch add stalker.mid save -f arc-grp-build music.grp

# Convert an archive into another format
gamearch open duke3d.grp save -f arc-rff-blood-v301 duke3d.rff

To get a list of supported file formats, run:

gamearch --formats

Installation as a dependency

If you wish to make use of the library in your own project, install it in the usual way:

npm install @malvineous/gamearchive

See cli/index.js for example use. The quick start is:

const GameArchive = require('@malvineous/gamearchive');

// Read an archive into memory
const handler = GameArchive.getHandler('arc-grp-duke3d');
const content = fs.readFileSync('duke3d.grp');
let archive = handler.parse(content);

// List the files in the archive
archive.files.forEach(file => {
    console.log(file.name);
});

// Extract a file
const data = archive.files[0].getContent();
fs.writeFileSync(archive.files[0].name, data);

// Rename a file
archive.files[0].name = 'RENAMED.BIN';

// Remove a file
delete archive.files[1];

// Write the archive back to disk with the modifications
const outBuffer = handler.generate(archive);
fs.writeFileSync('new.grp', outBuffer);

Installation as a contributor

If you would like to help add more file formats to the library, great! Clone the repo, and to get started:

npm install --dev

Run the tests to make sure everything worked:

npm test

You're ready to go! To add a new file format:

Create a new file in the formats/ folder for your format. Copying an existing file that covers a similar format will help considerably. If you're not sure, arc-grp-build.js is a good starting point as it is fairly simple.
Edit the main index.js and add a require() statement for your new file.
Make a folder in test/ for your new format and populate it with files similar to the other formats. The tests work by creating a standard archive file with some preset files in it, and comparing the result to what is inside this folder.

You can either create these archives by hand, with another utility, or if you are confident that your code is correct, from the code itself. This is done by setting an environment variable when running the tests, which will cause the archive file produced by your code to be saved to a temporary file in the current directory:
```
SAVE_FAILED_TEST=1 npm test
mv error1.bin test/arc-myformat/default.bin
```

If your archive format has any sort of compression or encryption, these algorithms should go into the gamecomp project instead. This is to make it easier to reuse the algorithms, as many of them (particularly the compression ones) are used amongst many unrelated archive formats. All the gamecomp algorithms are available to be used by any archive format in this library.

During development you can test your algorithm like this:

# Read a sample archive and list the files, with debug messages on
$ ./bin/gamearch --debug open -f arc-myformat example.dat list

# Make sure the format is identified correctly or if not why not
$ ./bin/gamearch --debug identify example.dat

If you use Debug.log rather than console.log then these messages can be left in for future diagnosis as they will only appear when --debug is given.

@malvineous/gamearchivedeprecated

Usage no npm install needed!