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@sebastien-p
Created June 14, 2011 09:10
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Tweet-sized JavaScript implementation of the Lempel–Ziv–Welch universal lossless data compression algorithm.
// Please, see http://rosettacode.org/wiki/LZW_compression#JavaScript
// and http://en.wikipedia.org/wiki/Lempel–Ziv–Welch for more infos.
function (
a // String to compress and placeholder for 'wc'.
){
for (
var b = a + "Ā", // Append first "illegal" character (charCode === 256).
c = [], // dictionary
d = 0, // dictionary size
e = d, // iterator
f = c, // w
g = c, // result
h; // c
h = b.charAt(e++);
)
c[h] = h.charCodeAt(), // Fill in the dictionary ...
f = 1 + c[a = f + h] ? a : (g[d++] = c[f], c[a] = d + 255, h); // ... and use it to compress data.
return g // Array of compressed data.
}
function(a){for(var b=a+"Ā",c=[],d=0,e=d,f=c,g=c,h;h=b.charAt(e++);)c[h]=h.charCodeAt(),f=1+c[a=f+h]?a:(g[d++]=c[f],c[a]=d+255,h);return g}
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
Version 2, December 2004
Copyright (C) 2011 Sebastien P. https://twitter.com/#!/_sebastienp
Special thanks to @subzey (you rock) and @kbjr !
Everyone is permitted to copy and distribute verbatim or modified
copies of this license document, and changing it is allowed as long
as the name is changed.
DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
0. You just DO WHAT THE FUCK YOU WANT TO.
{
"name": "LZWcompress",
"description": "JavaScript implementation of the Lempel–Ziv–Welch universal lossless data compression algorithm.",
"keywords": [
"LZW",
"lossless",
"data",
"compression"
]
}
<!DOCTYPE html>
<title>Foo</title>
<div>Expected value: <b>84,79,66,69,79,82,78,79,84,256,258,260,265,259,261,263</b></div>
<div>Actual value: <b id="ret"></b></div>
<script>
var LZWcompress = function(a){for(var b=a+"Ā",c=[],d=0,e=d,f=c,g=c,h;h=b.charAt(e++);)c[h]=h.charCodeAt(),f=1+c[a=f+h]?a:(g[d++]=c[f],c[a]=d+255,h);return g}
document.getElementById("ret").innerHTML = LZWcompress("TOBEORNOTTOBEORTOBEORNOT")
</script>
@sebastien-p
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@subzey : Wonderful ! IE7 should not be a problem. I did something like that to say goodbye to push but gave up on it in the end.

@bytespider
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Well done guys, this truly is awesome

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