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JavaScript implementation of the Lempel–Ziv–Welch universal lossless data compression algorithm.
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| // Please, see http://rosettacode.org/wiki/LZW_compression#JavaScript for more infos. | |
| // Could fail in IE because of the 'str[x]' notation, should be better to use 'str.charAt(x)'. | |
| // Still 18 bytes to go (25 including '.charAt') ! | |
| function ( | |
| a, // String to compress | |
| b, // Placeholder for dictionary | |
| c, // Placeholder for dictionary size | |
| d, // Placeholder for iterator | |
| e, // Placeholder for w | |
| f, // Placeholder for result | |
| g, // Placeholder for c | |
| h // Placeholder for wc | |
| ){ | |
| for (b = {}, c = d = 256; b[String.fromCharCode(d)] = d--;); | |
| for (e = f = []; g = a[++d];) | |
| e = b[h = e + g] ? h : (f.push(b[e]), b[h] = c++, g); | |
| f.push(b[e]); | |
| return f | |
| } |
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| function(a,b,c,d,e,f,g,h){for(b={},c=d=256;b[String.fromCharCode(d)]=d--;);for(e=f=[];g=a[++d];)e=b[h=e+g]?h:(f.push(b[e]),b[h]=c++,g);f.push(b[e]);return f} |
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| DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE | |
| Version 2, December 2004 | |
| Copyright (C) 2011 Sebastien P. https://twitter.com/#!/_sebastienp | |
| 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. |
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| { | |
| "name": "LZWcompress", | |
| "description": "JavaScript implementation of the Lempel–Ziv–Welch universal lossless data compression algorithm.", | |
| "keywords": [ | |
| "LZW", | |
| "lossless", | |
| "data", | |
| "compression" | |
| ] | |
| } |
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| <!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,b,c,d,e,f,g,h){for(b={},c=d=256;b[String.fromCharCode(d)]=d--;);for(e=f=[];g=a[++d];)e=b[h=e+g]?h:(f.push(b[e]),b[h]=c++,g);f.push(b[e]);return f} | |
| document.getElementById("ret").innerHTML = LZW("TOBEORNOTTOBEORTOBEORNOT") | |
| </script> |
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I moved the
part into the for loop allowing the removal of the second d