62 lines
2 KiB
JavaScript
62 lines
2 KiB
JavaScript
/**
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* shortdash - https://github.com/bibig/node-shorthash
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*
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* @license
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*
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* (The MIT License)
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*
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* Copyright (c) 2013 Bibig <bibig@me.com>
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use,
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* copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the
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* Software is furnished to do so, subject to the following
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* conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
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* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
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* OTHER DEALINGS IN THE SOFTWARE.
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*/
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const dictionary = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXY";
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const binary = dictionary.length;
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function bitwise(str) {
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let hash = 0;
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if (str.length === 0)
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return hash;
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for (let i = 0; i < str.length; i++) {
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const ch = str.charCodeAt(i);
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hash = (hash << 5) - hash + ch;
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hash = hash & hash;
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}
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return hash;
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}
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function shorthash(text) {
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let num;
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let result = "";
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let integer = bitwise(text);
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const sign = integer < 0 ? "Z" : "";
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integer = Math.abs(integer);
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while (integer >= binary) {
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num = integer % binary;
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integer = Math.floor(integer / binary);
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result = dictionary[num] + result;
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}
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if (integer > 0) {
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result = dictionary[integer] + result;
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}
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return sign + result;
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}
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export {
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shorthash
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};
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