Rietveld Code Review Tool
Help | Bug tracker | Discussion group | Source code

Unified Diff: lib/lz-string.js

Issue 29350042: Issue 4023 - Move storage of subscription lists to localStorage (Closed)
Patch Set: Created Aug. 22, 2016, 9:24 a.m.
Use n/p to move between diff chunks; N/P to move between comments.
Jump to:
View side-by-side diff with in-line comments
Download patch
Index: lib/lz-string.js
===================================================================
new file mode 100644
--- /dev/null
+++ b/lib/lz-string.js
@@ -0,0 +1,506 @@
+// 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
Sebastian Noack 2016/08/22 16:49:19 While this license should theoretically work for u
Oleksandr 2016/08/25 02:02:37 Done. Judith is fine with this.
+// 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
+} else if( typeof angular !== 'undefined' && angular != null ) {
+ angular.module('LZString', [])
+ .factory('LZString', function () {
+ return LZString;
+ });
+}

Powered by Google App Engine
This is Rietveld