base64.js
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class Base64Fun {
constructor() {
this._keyStr = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='
}
_utf8_encode(string) {
string = string.replace(/\r\n/g, '\n')
let utftext = ''
for (let n = 0; n < string.length; n++) {
const c = string.charCodeAt(n)
if (c < 128) {
utftext += String.fromCharCode(c)
} else if ((c > 127) && (c < 2048)) {
utftext += String.fromCharCode((c >> 6) | 192)
utftext += String.fromCharCode((c & 63) | 128)
} else {
utftext += String.fromCharCode((c >> 12) | 224)
utftext += String.fromCharCode(((c >> 6) & 63) | 128)
utftext += String.fromCharCode((c & 63) | 128)
}
}
return utftext
}
_utf8_decode(utftext) {
let string = ''
let i = 0
let c = 0
let c1 = 0
let c2 = 0
while (i < utftext.length) {
c = utftext.charCodeAt(i)
if (c < 128) {
string += String.fromCharCode(c)
i++
} else if ((c > 191) && (c < 224)) {
c1 = utftext.charCodeAt(i + 1)
string += String.fromCharCode(((c & 31) << 6) | (c1 & 63))
i += 2
} else {
c1 = utftext.charCodeAt(i + 1)
c2 = utftext.charCodeAt(i + 2)
string += String.fromCharCode(((c & 15) << 12) | ((c1 & 63) << 6) | (c2 & 63))
i += 3
}
}
return string
}
encode(input) {
let output = ''
let chr1, chr2, chr3, enc1, enc2, enc3, enc4
let i = 0
input = this._utf8_encode(input)
while (i < input.length) {
chr1 = input.charCodeAt(i++)
chr2 = input.charCodeAt(i++)
chr3 = input.charCodeAt(i++)
enc1 = chr1 >> 2
enc2 = ((chr1 & 3) << 4) | (chr2 >> 4)
enc3 = ((chr2 & 15) << 2) | (chr3 >> 6)
enc4 = chr3 & 63
if (isNaN(chr2)) {
enc3 = enc4 = 64
} else if (isNaN(chr3)) {
enc4 = 64
}
output = output +
this._keyStr.charAt(enc1) + this._keyStr.charAt(enc2) +
this._keyStr.charAt(enc3) + this._keyStr.charAt(enc4)
}
return output
}
decode(input) {
let output = ''
let chr1, chr2, chr3
let enc1, enc2, enc3, enc4
let i = 0
input = input.replace(/[^A-Za-z0-9\+\/\=]/g, '')
while (i < input.length) {
enc1 = this._keyStr.indexOf(input.charAt(i++))
enc2 = this._keyStr.indexOf(input.charAt(i++))
enc3 = this._keyStr.indexOf(input.charAt(i++))
enc4 = this._keyStr.indexOf(input.charAt(i++))
chr1 = (enc1 << 2) | (enc2 >> 4)
chr2 = ((enc2 & 15) << 4) | (enc3 >> 2)
chr3 = ((enc3 & 3) << 6) | enc4
output = output + String.fromCharCode(chr1)
if (enc3 != 64) {
output = output + String.fromCharCode(chr2)
}
if (enc4 != 64) {
output = output + String.fromCharCode(chr3)
}
}
output = this._utf8_decode(output)
return output
}
}