lzjb is a fast pure JavaScript implementation of LZJB
compression/decompression. It was originally written by "Bear"
based on the OpenSolaris C implementations.
C. Scott Ananian cleaned up the source code and packaged it for node
and volo.
npm install lzjb
or
volo add cscott/lzjb
This package uses Typed Arrays and so requires node.js >= 0.5.5. Full browser compatibility table is available at caniuse.com; briefly: IE 10, Firefox 4, Chrome 7, or Safari 5.1.
npm install
npm test
There is a binary available in bin:
$ bin/lzjb --help
$ echo "Test me" | bin/lzjb -z > test.lzjb
$ bin/lzjb -d test.lzjb
Test me
From JavaScript:
var lzjb = require('lzjb');
var data = new Buffer('Example data', 'utf8');
var compressed = lzjb.compressFile(data);
var uncompressed = lzjb.uncompressFile(compressed);
// convert from array back to string
var data2 = new Buffer(uncompressed).toString('utf8');
console.log(data2);
There is a streaming interface as well.
See the tests in the tests/ directory for further usage examples.
require('lzjb') returns a lzjb object. It contains two main
methods. The first is a function accepting one, two or three parameters:
lzjb.compressFile = function(input, [output], [Number compressionLevel])
The input argument can be a "stream" object (which must implement the
readByte method), or a Uint8Array, Buffer, or array.
If you omit the second argument, compressFile will return a JavaScript
array containing the byte values of the compressed data. If you pass
a second argument, it must be a "stream" object (which must implement the
writeByte method).
The third argument may be omitted, or a number between 1 and 9 indicating
a compression level (1 being largest/fastest compression and 9 being
smallest/slowest compression). The default is 1. 6 is about twice
as slow but creates 10% smaller files.
The second exported method is a function accepting one or two parameters:
lzjb.decompressFile = function(input, [output])
The input parameter is as above.
If you omit the second argument, decompressFile will return a
Uint8Array, Buffer or JavaScript array with the decompressed
data, depending on what your platform supports. For most modern
platforms (modern browsers, recent node.js releases) the returned
value will be a Uint8Array.
If you provide the second argument, it must be a "stream", implementing
the writeByte method.
- https://code.google.com/p/jslzjb/ Original JavaScript port by Bear
- http://en.wikipedia.org/wiki/LZJB Wikipedia article on LZJB compression
- http://src.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/os/compress.c "compress" source code (describes LZJB algorithm)
- http://cvs.opensolaris.org/source/xref/onnv/onnv-gate/usr/src/uts/common/fs/zfs/lzjb.c In-kernel implementation of LZJB
- https://github.com/cscott/lzma-purejs LZMA
- https://github.com/cscott/seek-bzip Bzip2 (random-access decompression)
Copyright (c) 2010 Nuwa Information Co., Ltd, and individual contributors.
Copyright (c) 2013 C. Scott Ananian
All rights reserved.
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Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
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