Bilibili BV2AV

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使用 AV 号替换 Bilibili 视频地址中的 BV 号

当前为 2020-03-24 提交的版本，查看最新版本。

换行

// ==UserScript==
// @name         Bilibili BV2AV
// @namespace    https://konge.pw/
// @supportURL   https://github.com/zkonge/bv2av/issues
// @homepage     https://github.com/zkonge/bv2av
// @version      0.1
// @description  使用 AV 号替换 Bilibili 视频地址中的 BV 号
// @author       zkonge
// @include      *://www.bilibili.com/video/*
// @grant        none
// ==/UserScript==

// From https://github.com/Coxxs/bvid

let table = 'fZodR9XQDSUm21yCkr6zBqiveYah8bt4xsWpHnJE7jL5VG3guMTKNPAwcF'
let tr = {}
for (let i = 0; i < 58; i++) {
  tr[table[i]] = i
}
let s = [11, 10, 3, 8, 4, 6, 2, 9, 5, 7]
let xor = BigInt('177451812')
let add = BigInt('100618342136696320')

function decode(x) {
  let r = BigInt(0)
  for (let i = 0; i < 10; i++) {
    r += BigInt(tr[x[s[i]]]) * (BigInt(58) ** BigInt(i))
  }
  r = ((r - add) ^ xor)
  return r > 0 && r < 1e9 ? r : null
}

const regex = /video\/(?<BV>[Bb][Vv][^\?]*)\?*/;

(function() {
    let path = location.toString();
    const check = regex.exec(path);
    if(check){
        const AV = decode(check.groups.BV);
        path = path.replace(check.groups.BV, 'av' + AV);
        history.replaceState(history.state, '',path);
    }
})();