507 lines
16 KiB
JavaScript
507 lines
16 KiB
JavaScript
// Copyright (c) 2013 Pieroxy <pieroxy@pieroxy.net>
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// This work is free. You can redistribute it and/or modify it
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// under the terms of the WTFPL, Version 2
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// For more information see LICENSE.txt or http://www.wtfpl.net/
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//
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// For more information, the home page:
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// http://pieroxy.net/blog/pages/lz-string/testing.html
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//
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// LZ-based compression algorithm, version 1.4.5
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var LZString = (function() {
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// private property
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var f = String.fromCharCode;
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var keyStrBase64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
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var keyStrUriSafe = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-$";
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var baseReverseDic = {};
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function getBaseValue(alphabet, character) {
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if (!baseReverseDic[alphabet]) {
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baseReverseDic[alphabet] = {};
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for (var i=0 ; i<alphabet.length ; i++) {
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baseReverseDic[alphabet][alphabet.charAt(i)] = i;
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}
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}
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return baseReverseDic[alphabet][character];
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}
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var LZString = {
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compressToBase64 : function (input) {
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if (input == null) return "";
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var res = LZString._compress(input, 6, function(a){return keyStrBase64.charAt(a);});
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switch (res.length % 4) { // To produce valid Base64
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default: // When could this happen ?
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case 0 : return res;
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case 1 : return res+"===";
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case 2 : return res+"==";
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case 3 : return res+"=";
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}
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},
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decompressFromBase64 : function (input) {
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if (input == null) return "";
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if (input == "") return null;
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return LZString._decompress(input.length, 32, function(index) { return getBaseValue(keyStrBase64, input.charAt(index)); });
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},
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compressToUTF16 : function (input) {
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if (input == null) return "";
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return LZString._compress(input, 15, function(a){return f(a+32);}) + " ";
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},
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decompressFromUTF16: function (compressed) {
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if (compressed == null) return "";
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if (compressed == "") return null;
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return LZString._decompress(compressed.length, 16384, function(index) { return compressed.charCodeAt(index) - 32; });
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},
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//compress into uint8array (UCS-2 big endian format)
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compressToUint8Array: function (uncompressed) {
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var compressed = LZString.compress(uncompressed);
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var buf=new Uint8Array(compressed.length*2); // 2 bytes per character
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for (var i=0, TotalLen=compressed.length; i<TotalLen; i++) {
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var current_value = compressed.charCodeAt(i);
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buf[i*2] = current_value >>> 8;
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buf[i*2+1] = current_value % 256;
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}
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return buf;
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},
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//decompress from uint8array (UCS-2 big endian format)
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decompressFromUint8Array:function (compressed) {
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if (compressed===null || compressed===undefined){
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return LZString.decompress(compressed);
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} else {
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var buf=new Array(compressed.length/2); // 2 bytes per character
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for (var i=0, TotalLen=buf.length; i<TotalLen; i++) {
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buf[i]=compressed[i*2]*256+compressed[i*2+1];
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}
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var result = [];
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buf.forEach(function (c) {
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result.push(f(c));
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});
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return LZString.decompress(result.join(''));
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}
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},
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//compress into a string that is already URI encoded
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compressToEncodedURIComponent: function (input) {
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if (input == null) return "";
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return LZString._compress(input, 6, function(a){return keyStrUriSafe.charAt(a);});
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},
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//decompress from an output of compressToEncodedURIComponent
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decompressFromEncodedURIComponent:function (input) {
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if (input == null) return "";
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if (input == "") return null;
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input = input.replace(/ /g, "+");
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return LZString._decompress(input.length, 32, function(index) { return getBaseValue(keyStrUriSafe, input.charAt(index)); });
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},
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compress: function (uncompressed) {
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return LZString._compress(uncompressed, 16, function(a){return f(a);});
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},
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_compress: function (uncompressed, bitsPerChar, getCharFromInt) {
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if (uncompressed == null) return "";
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var i, value,
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context_dictionary= {},
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context_dictionaryToCreate= {},
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context_c="",
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context_wc="",
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context_w="",
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context_enlargeIn= 2, // Compensate for the first entry which should not count
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context_dictSize= 3,
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context_numBits= 2,
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context_data=[],
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context_data_val=0,
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context_data_position=0,
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ii;
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for (ii = 0; ii < uncompressed.length; ii += 1) {
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context_c = uncompressed.charAt(ii);
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if (!Object.prototype.hasOwnProperty.call(context_dictionary,context_c)) {
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context_dictionary[context_c] = context_dictSize++;
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context_dictionaryToCreate[context_c] = true;
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}
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context_wc = context_w + context_c;
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if (Object.prototype.hasOwnProperty.call(context_dictionary,context_wc)) {
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context_w = context_wc;
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} else {
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if (Object.prototype.hasOwnProperty.call(context_dictionaryToCreate,context_w)) {
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if (context_w.charCodeAt(0)<256) {
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for (i=0 ; i<context_numBits ; i++) {
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context_data_val = (context_data_val << 1);
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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}
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value = context_w.charCodeAt(0);
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for (i=0 ; i<8 ; i++) {
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context_data_val = (context_data_val << 1) | (value&1);
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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value = value >> 1;
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}
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} else {
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value = 1;
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for (i=0 ; i<context_numBits ; i++) {
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context_data_val = (context_data_val << 1) | value;
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if (context_data_position ==bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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value = 0;
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}
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value = context_w.charCodeAt(0);
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for (i=0 ; i<16 ; i++) {
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context_data_val = (context_data_val << 1) | (value&1);
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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value = value >> 1;
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}
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}
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context_enlargeIn--;
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if (context_enlargeIn == 0) {
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context_enlargeIn = Math.pow(2, context_numBits);
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context_numBits++;
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}
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delete context_dictionaryToCreate[context_w];
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} else {
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value = context_dictionary[context_w];
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for (i=0 ; i<context_numBits ; i++) {
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context_data_val = (context_data_val << 1) | (value&1);
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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value = value >> 1;
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}
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}
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context_enlargeIn--;
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if (context_enlargeIn == 0) {
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context_enlargeIn = Math.pow(2, context_numBits);
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context_numBits++;
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}
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// Add wc to the dictionary.
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context_dictionary[context_wc] = context_dictSize++;
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context_w = String(context_c);
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}
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}
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// Output the code for w.
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if (context_w !== "") {
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if (Object.prototype.hasOwnProperty.call(context_dictionaryToCreate,context_w)) {
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if (context_w.charCodeAt(0)<256) {
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for (i=0 ; i<context_numBits ; i++) {
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context_data_val = (context_data_val << 1);
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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}
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value = context_w.charCodeAt(0);
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for (i=0 ; i<8 ; i++) {
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context_data_val = (context_data_val << 1) | (value&1);
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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value = value >> 1;
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}
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} else {
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value = 1;
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for (i=0 ; i<context_numBits ; i++) {
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context_data_val = (context_data_val << 1) | value;
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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value = 0;
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}
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value = context_w.charCodeAt(0);
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for (i=0 ; i<16 ; i++) {
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context_data_val = (context_data_val << 1) | (value&1);
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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value = value >> 1;
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}
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}
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context_enlargeIn--;
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if (context_enlargeIn == 0) {
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context_enlargeIn = Math.pow(2, context_numBits);
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context_numBits++;
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}
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delete context_dictionaryToCreate[context_w];
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} else {
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value = context_dictionary[context_w];
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for (i=0 ; i<context_numBits ; i++) {
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context_data_val = (context_data_val << 1) | (value&1);
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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value = value >> 1;
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}
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}
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context_enlargeIn--;
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if (context_enlargeIn == 0) {
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context_enlargeIn = Math.pow(2, context_numBits);
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context_numBits++;
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}
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}
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// Mark the end of the stream
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value = 2;
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for (i=0 ; i<context_numBits ; i++) {
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context_data_val = (context_data_val << 1) | (value&1);
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if (context_data_position == bitsPerChar-1) {
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context_data_position = 0;
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context_data.push(getCharFromInt(context_data_val));
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context_data_val = 0;
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} else {
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context_data_position++;
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}
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value = value >> 1;
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}
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// Flush the last char
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while (true) {
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context_data_val = (context_data_val << 1);
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if (context_data_position == bitsPerChar-1) {
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context_data.push(getCharFromInt(context_data_val));
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break;
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}
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else context_data_position++;
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}
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return context_data.join('');
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},
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decompress: function (compressed) {
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if (compressed == null) return "";
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if (compressed == "") return null;
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return LZString._decompress(compressed.length, 32768, function(index) { return compressed.charCodeAt(index); });
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},
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_decompress: function (length, resetValue, getNextValue) {
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var dictionary = [],
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next,
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enlargeIn = 4,
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dictSize = 4,
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numBits = 3,
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entry = "",
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result = [],
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i,
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w,
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bits, resb, maxpower, power,
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c,
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data = {val:getNextValue(0), position:resetValue, index:1};
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for (i = 0; i < 3; i += 1) {
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dictionary[i] = i;
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}
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bits = 0;
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maxpower = Math.pow(2,2);
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power=1;
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while (power!=maxpower) {
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resb = data.val & data.position;
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data.position >>= 1;
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if (data.position == 0) {
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data.position = resetValue;
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data.val = getNextValue(data.index++);
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}
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bits |= (resb>0 ? 1 : 0) * power;
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power <<= 1;
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}
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switch (next = bits) {
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case 0:
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bits = 0;
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maxpower = Math.pow(2,8);
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power=1;
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while (power!=maxpower) {
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resb = data.val & data.position;
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data.position >>= 1;
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if (data.position == 0) {
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data.position = resetValue;
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data.val = getNextValue(data.index++);
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}
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bits |= (resb>0 ? 1 : 0) * power;
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power <<= 1;
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}
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c = f(bits);
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break;
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case 1:
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bits = 0;
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maxpower = Math.pow(2,16);
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power=1;
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while (power!=maxpower) {
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resb = data.val & data.position;
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data.position >>= 1;
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if (data.position == 0) {
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data.position = resetValue;
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data.val = getNextValue(data.index++);
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}
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bits |= (resb>0 ? 1 : 0) * power;
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power <<= 1;
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}
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c = f(bits);
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break;
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case 2:
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return "";
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}
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dictionary[3] = c;
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w = c;
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result.push(c);
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while (true) {
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if (data.index > length) {
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return "";
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}
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bits = 0;
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maxpower = Math.pow(2,numBits);
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power=1;
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while (power!=maxpower) {
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resb = data.val & data.position;
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data.position >>= 1;
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if (data.position == 0) {
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data.position = resetValue;
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data.val = getNextValue(data.index++);
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}
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bits |= (resb>0 ? 1 : 0) * power;
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power <<= 1;
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}
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switch (c = bits) {
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case 0:
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bits = 0;
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maxpower = Math.pow(2,8);
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power=1;
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while (power!=maxpower) {
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resb = data.val & data.position;
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data.position >>= 1;
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if (data.position == 0) {
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data.position = resetValue;
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data.val = getNextValue(data.index++);
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}
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bits |= (resb>0 ? 1 : 0) * power;
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power <<= 1;
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}
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dictionary[dictSize++] = f(bits);
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c = dictSize-1;
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enlargeIn--;
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break;
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case 1:
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bits = 0;
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maxpower = Math.pow(2,16);
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power=1;
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while (power!=maxpower) {
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resb = data.val & data.position;
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data.position >>= 1;
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if (data.position == 0) {
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data.position = resetValue;
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data.val = getNextValue(data.index++);
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}
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bits |= (resb>0 ? 1 : 0) * power;
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power <<= 1;
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}
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dictionary[dictSize++] = f(bits);
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c = dictSize-1;
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enlargeIn--;
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break;
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case 2:
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return result.join('');
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}
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if (enlargeIn == 0) {
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enlargeIn = Math.pow(2, numBits);
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numBits++;
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}
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if (dictionary[c]) {
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entry = dictionary[c];
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} else {
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if (c === dictSize) {
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entry = w + w.charAt(0);
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} else {
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return null;
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}
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}
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result.push(entry);
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// Add w+entry[0] to the dictionary.
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dictionary[dictSize++] = w + entry.charAt(0);
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enlargeIn--;
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w = entry;
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if (enlargeIn == 0) {
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enlargeIn = Math.pow(2, numBits);
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numBits++;
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}
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}
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}
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};
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return LZString;
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})();
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if (typeof define === 'function' && define.amd) {
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define(function () { return LZString; });
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} else if( typeof module !== 'undefined' && module != null ) {
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module.exports = LZString
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} else if( typeof angular !== 'undefined' && angular != null ) {
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angular.module('LZString', [])
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.factory('LZString', function () {
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return LZString;
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});
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}
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