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/**
* shortdash - https://github.com/bibig/node-shorthash
*
* @license
*
* (The MIT License)
*
* Copyright (c) 2013 Bibig <bibig@me.com>
*
* Permission is hereby granted, free of charge, to any person
* obtaining a copy of this software and associated documentation
* files (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use,
* copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following
* conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
const dictionary = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXY';
const binary = dictionary.length;
// refer to: http://werxltd.com/wp/2010/05/13/javascript-implementation-of-javas-string-hashcode-method/
function bitwise(str: string) {
let hash = 0;
if (str.length === 0) return hash;
for (let i = 0; i < str.length; i++) {
const ch = str.charCodeAt(i);
hash = (hash << 5) - hash + ch;
hash = hash & hash; // Convert to 32bit integer
}
return hash;
}
export function shorthash(text: string) {
let num: number;
let result = '';
let integer = bitwise(text);
const sign = integer < 0 ? 'Z' : ''; // It it's negative, start with Z, which isn't in the dictionary
integer = Math.abs(integer);
while (integer >= binary) {
num = integer % binary;
integer = Math.floor(integer / binary);
result = dictionary[num] + result;
}
if (integer > 0) {
result = dictionary[integer] + result;
}
return sign + result;
}
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