Genie Engine DRS file reader/writer for Node.js and the browser

.DRS files are archive files used in the Age of Empires 1 and 2 and Star Wars: Galactic Battlegrounds games. A format specification is available in the openage project.

Read a palette file and a unit graphic from the Age of Empires 2 data files:

var DRS = require('genie-drs')
var Palette = require('jascpal')
var SLP = require('genie-slp')
var PNG = require('pngjs').PNG

// using Age of Empires 2 files
var int = DRS('interfac.drs')
  , gra = DRS('graphics.drs')

// id 50500 is the main in-game palette.
int.readFile(50500, function (err, buffer) {
  if (err) throw err
  var palette = Palette(buffer)
  int.close()
  onpalette(palette)
})

function onpalette (palette) {
  // 3088 is the 'Champion Dying' graphic.
  gra.readFile(3088, function (err, buffer) {
    if (err) throw err
    var slp = SLP(buffer)
    onslp(palette, slp)
  })
}

function onslp (palette, slp) {
  var frame = slp.renderFrame(1, palette, { player: 1, drawOutline: false })
  var png = new PNG({
    width: frame.width,
    height: frame.height
  })
  png.data = Buffer.from(frame.data.buffer)
  png.pack().pipe(fs.createWriteStream('champion-dying.png'))
}

Create a new DRS file:

var DRS = require('genie-drs')
var after = require('after')
var drs = DRS()

var cb = after(3, onfinish)
fs.createReadStream('./somefile.slp').pipe(drs.createWriteStream('slp ', 1, cb))
fs.createReadStream('./bgm.wav').pipe(drs.createWriteStream('wav ', 2, cb))
fs.createReadStream('./palette.pal').pipe(drs.createWriteStream('bina', 3, cb))

function onfinish () {
  drs.archive().pipe(fs.createWriteStream('./archive.drs'))
}

Create a new DRS file. Options can be:

• isSWGB - Whether this is a file for Star Wars: Galactic Battlegrounds. Default false.
• copyright - Copyright string to use, uses the Age of Empires or Star Wars: Galactic Battlegrounds string by default. This should be exactly 40 characters long for DRS files intended for AoE and exactly 60 characters long for DRS files for SWGB.
• fileVersion - Version number as a 4-character string, default '1.00'.
• fileType - File type as a 12-character string, pad with NUL bytes. Default 'tribe\0\0\0\0\0\0\0' like in Age of Empires 2 files.

Node only!

Creates a new DRS instance for the .DRS file filename.

Browser only!

Creates a new DRS instance for the given Blob instance.

Reads the DRS table headers. This only needs to be called manually if getFiles() or getSize() is used. Otherwise, genie-drs will call it automatically when necessary.

Returns the size of the DRS file. Includes any unsaved modifications. Won't work if the file hasn't been .read() yet.

Returns an array of all the file entries in this DRS file. Format:

{ id: Number     // internal file ID
, type: String   // 4-character, space-padded type of file: "wav ", "slp ", "bina"
, size: Number   // file size in bytes
, offset: Number // file offset in the main DRS, in bytes
}

Won't work if the file hasn't been .read() yet.

Finds one file entry by its file ID. See DRS#getFiles()

Replaces one file in the DRS.

type is the file type, i.e. the table in which to store the file. If a file type is given for which a table does not exist, a new table is created. id is the new file ID. buffer is a Buffer or string with the new file contents.

Reads a file's contents for ID id. The callback gets an err and a Buffer containing the file contents.

Optionally, provide an options object to read only part of the file:

• start - Byte offset inside the file to start reading at.
• end - Byte offset inside the file to stop reading at.

Returns a Readable stream of the file contents for file ID id.

The returned stream also emits a meta event with information about the file, like in getFiles().

Optionally, provide an options object to read only part of the file:

• start - Byte offset inside the file to start reading at.
• end - Byte offset inside the file to stop reading at.

Returns a stream, stuff that is written to it will be saved in the DRS file. Note that this method works in-memory, use the archive() method to flush changes back to disk.

The returned stream emits a meta event with information about the new file, like in getFiles().

type is the file type, i.e. the table in which to store the file. If a file type is given for which a table does not exist, a new table is created. id is the new file ID.

Returns the entire DRS file as a stream. If the DRS instance was initialized from an existing DRS file, this method may attempt to read data from that file--it's not safe to pipe the stream straight back to the original DRS file. If that is necessary, use a module like fs-write-stream-atomic, which will not touch the initial file until everything has been read.

var createWriteStream = require('fs-write-stream-atomic')

var drs = DRS('./archive.drs')
fs.createReadStream('./custom-palette.pal')
  .pipe(drs.createWriteStream('bina', 50501))
  .on('finish', onfinish)

function onfinish () {
  drs.archive().pipe(createWriteStream('./archive.drs'))
}

• drs-extract - CLI for this module.

MIT