|
|
/*
|
|
|
* @Author: zhang peng
|
|
|
* @Date: 2021-08-03 10:57:51
|
|
|
* @LastEditTime: 2021-08-16 17:25:43
|
|
|
* @LastEditors: zhang peng
|
|
|
* @Description:
|
|
|
* @FilePath: \miniprogram-to-uniapp2\src\project\template\polyfill\base64Binary.js
|
|
|
*
|
|
|
* 借鉴自：https://github.com/dankogai/js-base64/blob/main/base64.js
|
|
|
* 因uniapp没有window，也无法使用Buffer，因此直接使用polyfill
|
|
|
*
|
|
|
*/
|
|
|
const b64ch = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
|
|
|
const b64chs = [...b64ch]
|
|
|
const b64re = /^(?:[A-Za-z\d+\/]{4})*?(?:[A-Za-z\d+\/]{2}(?:==)?|[A-Za-z\d+\/]{3}=?)?$/
|
|
|
const b64tab = ((a) => {
|
|
|
let tab = {}
|
|
|
a.forEach((c, i) => tab[c] = i)
|
|
|
return tab
|
|
|
})(b64chs)
|
|
|
const _fromCC = String.fromCharCode.bind(String)
|
|
|
|
|
|
/**
|
|
|
* polyfill version of `btoa`
|
|
|
*/
|
|
|
const btoaPolyfill = (bin) => {
|
|
|
// console.log('polyfilled');
|
|
|
let u32, c0, c1, c2, asc = ''
|
|
|
const pad = bin.length % 3
|
|
|
for (let i = 0;i < bin.length;) {
|
|
|
if ((c0 = bin.charCodeAt(i++)) > 255 ||
|
|
|
(c1 = bin.charCodeAt(i++)) > 255 ||
|
|
|
(c2 = bin.charCodeAt(i++)) > 255)
|
|
|
throw new TypeError('invalid character found')
|
|
|
u32 = (c0 << 16) | (c1 << 8) | c2
|
|
|
asc += b64chs[u32 >> 18 & 63]
|
|
|
+ b64chs[u32 >> 12 & 63]
|
|
|
+ b64chs[u32 >> 6 & 63]
|
|
|
+ b64chs[u32 & 63]
|
|
|
}
|
|
|
return pad ? asc.slice(0, pad - 3) + "===".substring(pad) : asc
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
* polyfill version of `atob`
|
|
|
*/
|
|
|
const atobPolyfill = (asc) => {
|
|
|
// console.log('polyfilled');
|
|
|
asc = asc.replace(/\s+/g, '')
|
|
|
if (!b64re.test(asc))
|
|
|
throw new TypeError('malformed base64.')
|
|
|
asc += '=='.slice(2 - (asc.length & 3))
|
|
|
let u24, bin = '', r1, r2
|
|
|
for (let i = 0;i < asc.length;) {
|
|
|
u24 = b64tab[asc.charAt(i++)] << 18
|
|
|
| b64tab[asc.charAt(i++)] << 12
|
|
|
| (r1 = b64tab[asc.charAt(i++)]) << 6
|
|
|
| (r2 = b64tab[asc.charAt(i++)])
|
|
|
bin += r1 === 64 ? _fromCC(u24 >> 16 & 255)
|
|
|
: r2 === 64 ? _fromCC(u24 >> 16 & 255, u24 >> 8 & 255)
|
|
|
: _fromCC(u24 >> 16 & 255, u24 >> 8 & 255, u24 & 255)
|
|
|
}
|
|
|
return bin
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
* base64转ArrayBuffer
|
|
|
*/
|
|
|
function base64ToArrayBuffer (base64) {
|
|
|
const binaryStr = atobPolyfill(base64)
|
|
|
const byteLength = binaryStr.length
|
|
|
const bytes = new Uint8Array(byteLength)
|
|
|
for (let i = 0;i < byteLength;i++) {
|
|
|
bytes[i] = binary.charCodeAt(i)
|
|
|
}
|
|
|
return bytes.buffer
|
|
|
}
|
|
|
|
|
|
/**
|
|
|
* ArrayBuffer转base64
|
|
|
*/
|
|
|
function arrayBufferToBase64 (buffer) {
|
|
|
let binaryStr = ""
|
|
|
const bytes = new Uint8Array(buffer)
|
|
|
var len = bytes.byteLength
|
|
|
for (let i = 0;i < len;i++) {
|
|
|
binaryStr += String.fromCharCode(bytes[i])
|
|
|
}
|
|
|
return btoaPolyfill(binaryStr)
|
|
|
}
|
|
|
|
|
|
module.exports = {
|
|
|
base64ToArrayBuffer,
|
|
|
arrayBufferToBase64,
|
|
|
}
|
