|
|
// Copyright (c) 2013 Pieroxy <pieroxy@pieroxy.net>
// This work is free. You can redistribute it and/or modify it
// under the terms of the WTFPL, Version 2
// For more information see LICENSE.txt or http://www.wtfpl.net/
//
// For more information, the home page:
// http://pieroxy.net/blog/pages/lz-string/testing.html
//
// LZ-based compression algorithm, version 1.4.4
var LZString = (function() {
// private property
var f = String.fromCharCode; var keyStrBase64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="; var keyStrUriSafe = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+-$"; var baseReverseDic = {};
function getBaseValue(alphabet, character) { if (!baseReverseDic[alphabet]) { baseReverseDic[alphabet] = {}; for (var i=0 ; i<alphabet.length ; i++) { baseReverseDic[alphabet][alphabet.charAt(i)] = i; } } return baseReverseDic[alphabet][character]; }
var LZString = { compressToBase64 : function (input) { if (input == null) return ""; var res = LZString._compress(input, 6, function(a){return keyStrBase64.charAt(a);}); switch (res.length % 4) { // To produce valid Base64
default: // When could this happen ?
case 0 : return res; case 1 : return res+"==="; case 2 : return res+"=="; case 3 : return res+"="; } },
decompressFromBase64 : function (input) { if (input == null) return ""; if (input == "") return null; return LZString._decompress(input.length, 32, function(index) { return getBaseValue(keyStrBase64, input.charAt(index)); }); },
compressToUTF16 : function (input) { if (input == null) return ""; return LZString._compress(input, 15, function(a){return f(a+32);}) + " "; },
decompressFromUTF16: function (compressed) { if (compressed == null) return ""; if (compressed == "") return null; return LZString._decompress(compressed.length, 16384, function(index) { return compressed.charCodeAt(index) - 32; }); },
//compress into uint8array (UCS-2 big endian format)
compressToUint8Array: function (uncompressed) { var compressed = LZString.compress(uncompressed); var buf=new Uint8Array(compressed.length*2); // 2 bytes per character
for (var i=0, TotalLen=compressed.length; i<TotalLen; i++) { var current_value = compressed.charCodeAt(i); buf[i*2] = current_value >>> 8; buf[i*2+1] = current_value % 256; } return buf; },
//decompress from uint8array (UCS-2 big endian format)
decompressFromUint8Array:function (compressed) { if (compressed===null || compressed===undefined){ return LZString.decompress(compressed); } else { var buf=new Array(compressed.length/2); // 2 bytes per character
for (var i=0, TotalLen=buf.length; i<TotalLen; i++) { buf[i]=compressed[i*2]*256+compressed[i*2+1]; }
var result = []; buf.forEach(function (c) { result.push(f(c)); }); return LZString.decompress(result.join(''));
}
},
//compress into a string that is already URI encoded
compressToEncodedURIComponent: function (input) { if (input == null) return ""; return LZString._compress(input, 6, function(a){return keyStrUriSafe.charAt(a);}); },
//decompress from an output of compressToEncodedURIComponent
decompressFromEncodedURIComponent:function (input) { if (input == null) return ""; if (input == "") return null; input = input.replace(/ /g, "+"); return LZString._decompress(input.length, 32, function(index) { return getBaseValue(keyStrUriSafe, input.charAt(index)); }); },
compress: function (uncompressed) { return LZString._compress(uncompressed, 16, function(a){return f(a);}); }, _compress: function (uncompressed, bitsPerChar, getCharFromInt) { if (uncompressed == null) return ""; var i, value, context_dictionary= {}, context_dictionaryToCreate= {}, context_c="", context_wc="", context_w="", context_enlargeIn= 2, // Compensate for the first entry which should not count
context_dictSize= 3, context_numBits= 2, context_data=[], context_data_val=0, context_data_position=0, ii;
for (ii = 0; ii < uncompressed.length; ii += 1) { context_c = uncompressed.charAt(ii); if (!Object.prototype.hasOwnProperty.call(context_dictionary,context_c)) { context_dictionary[context_c] = context_dictSize++; context_dictionaryToCreate[context_c] = true; }
context_wc = context_w + context_c; if (Object.prototype.hasOwnProperty.call(context_dictionary,context_wc)) { context_w = context_wc; } else { if (Object.prototype.hasOwnProperty.call(context_dictionaryToCreate,context_w)) { if (context_w.charCodeAt(0)<256) { for (i=0 ; i<context_numBits ; i++) { context_data_val = (context_data_val << 1); if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } } value = context_w.charCodeAt(0); for (i=0 ; i<8 ; i++) { context_data_val = (context_data_val << 1) | (value&1); if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } value = value >> 1; } } else { value = 1; for (i=0 ; i<context_numBits ; i++) { context_data_val = (context_data_val << 1) | value; if (context_data_position ==bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } value = 0; } value = context_w.charCodeAt(0); for (i=0 ; i<16 ; i++) { context_data_val = (context_data_val << 1) | (value&1); if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } value = value >> 1; } } context_enlargeIn--; if (context_enlargeIn == 0) { context_enlargeIn = Math.pow(2, context_numBits); context_numBits++; } delete context_dictionaryToCreate[context_w]; } else { value = context_dictionary[context_w]; for (i=0 ; i<context_numBits ; i++) { context_data_val = (context_data_val << 1) | (value&1); if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } value = value >> 1; }
} context_enlargeIn--; if (context_enlargeIn == 0) { context_enlargeIn = Math.pow(2, context_numBits); context_numBits++; } // Add wc to the dictionary.
context_dictionary[context_wc] = context_dictSize++; context_w = String(context_c); } }
// Output the code for w.
if (context_w !== "") { if (Object.prototype.hasOwnProperty.call(context_dictionaryToCreate,context_w)) { if (context_w.charCodeAt(0)<256) { for (i=0 ; i<context_numBits ; i++) { context_data_val = (context_data_val << 1); if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } } value = context_w.charCodeAt(0); for (i=0 ; i<8 ; i++) { context_data_val = (context_data_val << 1) | (value&1); if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } value = value >> 1; } } else { value = 1; for (i=0 ; i<context_numBits ; i++) { context_data_val = (context_data_val << 1) | value; if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } value = 0; } value = context_w.charCodeAt(0); for (i=0 ; i<16 ; i++) { context_data_val = (context_data_val << 1) | (value&1); if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } value = value >> 1; } } context_enlargeIn--; if (context_enlargeIn == 0) { context_enlargeIn = Math.pow(2, context_numBits); context_numBits++; } delete context_dictionaryToCreate[context_w]; } else { value = context_dictionary[context_w]; for (i=0 ; i<context_numBits ; i++) { context_data_val = (context_data_val << 1) | (value&1); if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } value = value >> 1; }
} context_enlargeIn--; if (context_enlargeIn == 0) { context_enlargeIn = Math.pow(2, context_numBits); context_numBits++; } }
// Mark the end of the stream
value = 2; for (i=0 ; i<context_numBits ; i++) { context_data_val = (context_data_val << 1) | (value&1); if (context_data_position == bitsPerChar-1) { context_data_position = 0; context_data.push(getCharFromInt(context_data_val)); context_data_val = 0; } else { context_data_position++; } value = value >> 1; }
// Flush the last char
while (true) { context_data_val = (context_data_val << 1); if (context_data_position == bitsPerChar-1) { context_data.push(getCharFromInt(context_data_val)); break; } else context_data_position++; } return context_data.join(''); },
decompress: function (compressed) { if (compressed == null) return ""; if (compressed == "") return null; return LZString._decompress(compressed.length, 32768, function(index) { return compressed.charCodeAt(index); }); },
_decompress: function (length, resetValue, getNextValue) { var dictionary = [], next, enlargeIn = 4, dictSize = 4, numBits = 3, entry = "", result = [], i, w, bits, resb, maxpower, power, c, data = {val:getNextValue(0), position:resetValue, index:1};
for (i = 0; i < 3; i += 1) { dictionary[i] = i; }
bits = 0; maxpower = Math.pow(2,2); power=1; while (power!=maxpower) { resb = data.val & data.position; data.position >>= 1; if (data.position == 0) { data.position = resetValue; data.val = getNextValue(data.index++); } bits |= (resb>0 ? 1 : 0) * power; power <<= 1; }
switch (next = bits) { case 0: bits = 0; maxpower = Math.pow(2,8); power=1; while (power!=maxpower) { resb = data.val & data.position; data.position >>= 1; if (data.position == 0) { data.position = resetValue; data.val = getNextValue(data.index++); } bits |= (resb>0 ? 1 : 0) * power; power <<= 1; } c = f(bits); break; case 1: bits = 0; maxpower = Math.pow(2,16); power=1; while (power!=maxpower) { resb = data.val & data.position; data.position >>= 1; if (data.position == 0) { data.position = resetValue; data.val = getNextValue(data.index++); } bits |= (resb>0 ? 1 : 0) * power; power <<= 1; } c = f(bits); break; case 2: return ""; } dictionary[3] = c; w = c; result.push(c); while (true) { if (data.index > length) { return ""; }
bits = 0; maxpower = Math.pow(2,numBits); power=1; while (power!=maxpower) { resb = data.val & data.position; data.position >>= 1; if (data.position == 0) { data.position = resetValue; data.val = getNextValue(data.index++); } bits |= (resb>0 ? 1 : 0) * power; power <<= 1; }
switch (c = bits) { case 0: bits = 0; maxpower = Math.pow(2,8); power=1; while (power!=maxpower) { resb = data.val & data.position; data.position >>= 1; if (data.position == 0) { data.position = resetValue; data.val = getNextValue(data.index++); } bits |= (resb>0 ? 1 : 0) * power; power <<= 1; }
dictionary[dictSize++] = f(bits); c = dictSize-1; enlargeIn--; break; case 1: bits = 0; maxpower = Math.pow(2,16); power=1; while (power!=maxpower) { resb = data.val & data.position; data.position >>= 1; if (data.position == 0) { data.position = resetValue; data.val = getNextValue(data.index++); } bits |= (resb>0 ? 1 : 0) * power; power <<= 1; } dictionary[dictSize++] = f(bits); c = dictSize-1; enlargeIn--; break; case 2: return result.join(''); }
if (enlargeIn == 0) { enlargeIn = Math.pow(2, numBits); numBits++; }
if (dictionary[c]) { entry = dictionary[c]; } else { if (c === dictSize) { entry = w + w.charAt(0); } else { return null; } } result.push(entry);
// Add w+entry[0] to the dictionary.
dictionary[dictSize++] = w + entry.charAt(0); enlargeIn--;
w = entry;
if (enlargeIn == 0) { enlargeIn = Math.pow(2, numBits); numBits++; }
} } }; return LZString; })();
if (typeof define === 'function' && define.amd) { define(function () { return LZString; }); } else if( typeof module !== 'undefined' && module != null ) { module.exports = LZString }
|