login.lumbung.space/default-themes/base/login/resources/js/base64url.js
2021-05-05 11:50:45 +02:00

115 lines
3.5 KiB
JavaScript

// for embedded scripts, quoted and modified from https://github.com/swansontec/rfc4648.js by William Swanson
'use strict';
var base64url = base64url || {};
(function(base64url) {
function parse (string, encoding, opts = {}) {
// Build the character lookup table:
if (!encoding.codes) {
encoding.codes = {};
for (let i = 0; i < encoding.chars.length; ++i) {
encoding.codes[encoding.chars[i]] = i;
}
}
// The string must have a whole number of bytes:
if (!opts.loose && (string.length * encoding.bits) & 7) {
throw new SyntaxError('Invalid padding');
}
// Count the padding bytes:
let end = string.length;
while (string[end - 1] === '=') {
--end;
// If we get a whole number of bytes, there is too much padding:
if (!opts.loose && !(((string.length - end) * encoding.bits) & 7)) {
throw new SyntaxError('Invalid padding');
}
}
// Allocate the output:
const out = new (opts.out || Uint8Array)(((end * encoding.bits) / 8) | 0);
// Parse the data:
let bits = 0; // Number of bits currently in the buffer
let buffer = 0; // Bits waiting to be written out, MSB first
let written = 0; // Next byte to write
for (let i = 0; i < end; ++i) {
// Read one character from the string:
const value = encoding.codes[string[i]];
if (value === void 0) {
throw new SyntaxError('Invalid character ' + string[i]);
}
// Append the bits to the buffer:
buffer = (buffer << encoding.bits) | value;
bits += encoding.bits;
// Write out some bits if the buffer has a byte's worth:
if (bits >= 8) {
bits -= 8;
out[written++] = 0xff & (buffer >> bits);
}
}
// Verify that we have received just enough bits:
if (bits >= encoding.bits || 0xff & (buffer << (8 - bits))) {
throw new SyntaxError('Unexpected end of data');
}
return out
}
function stringify (data, encoding, opts = {}) {
const { pad = true } = opts;
const mask = (1 << encoding.bits) - 1;
let out = '';
let bits = 0; // Number of bits currently in the buffer
let buffer = 0; // Bits waiting to be written out, MSB first
for (let i = 0; i < data.length; ++i) {
// Slurp data into the buffer:
buffer = (buffer << 8) | (0xff & data[i]);
bits += 8;
// Write out as much as we can:
while (bits > encoding.bits) {
bits -= encoding.bits;
out += encoding.chars[mask & (buffer >> bits)];
}
}
// Partial character:
if (bits) {
out += encoding.chars[mask & (buffer << (encoding.bits - bits))];
}
// Add padding characters until we hit a byte boundary:
if (pad) {
while ((out.length * encoding.bits) & 7) {
out += '=';
}
}
return out
}
const encoding = {
chars: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_',
bits: 6
}
base64url.decode = function (string, opts) {
return parse(string, encoding, opts);
}
base64url.encode = function (data, opts) {
return stringify(data, encoding, opts)
}
return base64url;
}(base64url));