Rumkin Compression

These are the ciphers that are used to power the pages involving compression at rumkin.com.

Available Libraries

• huffman - A Huffman encoder for Buffer objects.
• huffmanAscii - Huffman encoding of strings. Results are in Base64.
• lz77 - Implementation of LZ77 for Buffer objects.
• lz77 - LZ77 that uses a custom Base91 encoding.

How to Use

Every library exports the same interface. It can be called synchronously or asynchronously.

// First, pick your library.
var library = require("@fidian/rumkin-compression").lz77;

// Synchronous compression and decompression.
resultBuffer = library.compressSync(inputBuffer);
decompressedBuffer = library.decompressSync(resultBuffer);

// Promised compression and decompression.
library.compressAsync(inputBuffer).then((resultBuffer) => {
    return library.decompressAsync(resultBuffer);
}).then((decompressedBuffer) => { ... });

// Asynchronous/callback based compression.
// Callback definition: callback(err, resultBuffer)
// Progress definition: progress(progressDataObject)
// Call the cancel function to abort compression/decompression
cancelFn = library.compress(inputBuffer, callbackFn, [progressFn]);
cancelFn = library.decompress(inputBuffer, callbackFn, [progressFn]);

// Managing the async/sync stuff yourself.
compressor = library.compressDirect(inputBuffer);
decompressor = library.decompressDirect(inputBuffer);

// Tiny sync version of a decompressor for a browser.
// For ASCII flavors, this takes the encoded string. For the Buffer
// variants, this takes a Buffer or any array-like thing where the values
// are the character codes (eg. input[0] == 97). They always return a
// string.
result = library.decompressTiny(inputBufferOrTypedArray);

Making Tiny Tinier

The tiny, synchronous functions of decompressors available for use in web pages. They are self-contained functions, so you could call .toString() on the functions to minify them.

// Minifying a tiny decompressor by using `.toString()` on the exported
// function. This isn't very fun and you could just minify the file
// itself instead.
uglifyJs = require("uglifyjs");
tinyDecompress = uglifyJs({
    lz77DecompressTiny: compression.lz77.decompressTiny.toString(),
}, {
    fromString: true,
    ... other options ...
});

Alternately, you can minify from the command line.

uglifyjs node-modules/@fidian/rumkin-compression/lib/lz77/decompress-tiny.js --screw-ie8 -m -c

Installation

Use npm to install this package easily.

$ npm install --save @fidian/rumkin-compression

Alternately you may edit your package.json and add this to your dependencies object:

{
    ...
    "dependencies": {
        ...
        "@fidian/rumkin-compression": "*"
        ...
    }
    ...
}

License

This software is licensed under a MIT license that contains additional non-advertising and patent-related clauses. Read full license terms