utils/compression.js

A module for ac-bundle-app, published by ac-bundle-module.

Available Methods: compress, decompress

compress

function(s) {
  var dict = {};
  var data = (s + "").split("");
  var out = [];
  var currChar;
  var phrase = data[0];
  var code = 256;
  for (var i=1; i    currChar=data[i];
    if (dict[phrase + currChar] != null) {
      phrase += currChar;
    }
    else {
      out.push(phrase.length > 1 ? dict[phrase] : phrase.charCodeAt(0));
      dict[phrase + currChar] = code;
      code++;
      phrase=currChar;
    }
  }
  out.push(phrase.length > 1 ? dict[phrase] : phrase.charCodeAt(0));
  for (var i=0; i    out[i] = String.fromCharCode(out[i]);
  }
  return out.join("");
}
decompress

function(s) {
  var dict = {};
  var data = (s + "").split("");
  var currChar = data[0];
  var oldPhrase = currChar;
  var out = [currChar];
  var code = 256;
  var phrase;
  for (var i=1; i    var currCode = data[i].charCodeAt(0);
    if (currCode < 256) {
      phrase = data[i];
    }
    else {
     phrase = dict[currCode] ? dict[currCode] : (oldPhrase + currChar);
    }
    out.push(phrase);
    currChar = phrase.charAt(0);
    dict = oldPhrase + currChar;
    code++;
    oldPhrase = phrase;
  }
  return out.join("");
}

Happy Coding!