implode-decoder

A pure JavaScript decoder for the PKWare implode compression algorithm.



Note that this is not the same implode algorithm as used in PKZip (compression method 6), but
rather a standalone one that was often used in 90s-era games (e.g. StarCraft, Diablo). I believe
these algorithms are similar, but at the very least the header formats differ.

Implementation is inspired by StormLib's explode.c.

Usage

The only exported function in this module is a function to create a streams2 Transform stream. You
may use the resulting stream as you would any other Transform stream.

``javascript
var decodeImplode = require('implode-decoder')
, fs = require('fs')

fs.createReadStream('myFile.example')
.pipe(decodeImplode())
.pipe(fs.createWriteStream('decompressed'))
`

Performance

A simple performance test of a "large" imploded file is included in the perf/ directory. I've run
this test alongside an analagous test written in C using StormLib, with the following results:

StormLib: median: 4.468634 ms

implode-decoder: median: 4.314142 ms`

Performance characteristics should be relatively similar to StormLib's implementation, although this
version supports fully streaming data input, so is a bit more flexible (StormLib's operates on a
"pull"-type interface, and expects to have access to data when it needs it).

LICENSE

MIT