63 lines
2.0 KiB
Plaintext
63 lines
2.0 KiB
Plaintext
/**
|
|
* 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;
|
|
function bitwise(str) {
|
|
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;
|
|
}
|
|
return hash;
|
|
}
|
|
function shorthash(text) {
|
|
let num;
|
|
let result = "";
|
|
let integer = bitwise(text);
|
|
const sign = integer < 0 ? "Z" : "";
|
|
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;
|
|
}
|
|
export {
|
|
shorthash
|
|
};
|