MeshCentral/public/novnc/core/base64.js
2020-06-06 18:55:47 -07:00

105 lines
4.1 KiB
JavaScript

/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
// From: http://hg.mozilla.org/mozilla-central/raw-file/ec10630b1a54/js/src/devtools/jint/sunspider/string-base64.js
import * as Log from './util/logging.js';
export default {
/* Convert data (an array of integers) to a Base64 string. */
toBase64Table: 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/='.split(''),
base64Pad: '=',
encode(data) {
"use strict";
let result = '';
const length = data.length;
const lengthpad = (length % 3);
// Convert every three bytes to 4 ascii characters.
for (let i = 0; i < (length - 2); i += 3) {
result += this.toBase64Table[data[i] >> 2];
result += this.toBase64Table[((data[i] & 0x03) << 4) + (data[i + 1] >> 4)];
result += this.toBase64Table[((data[i + 1] & 0x0f) << 2) + (data[i + 2] >> 6)];
result += this.toBase64Table[data[i + 2] & 0x3f];
}
// Convert the remaining 1 or 2 bytes, pad out to 4 characters.
const j = length - lengthpad;
if (lengthpad === 2) {
result += this.toBase64Table[data[j] >> 2];
result += this.toBase64Table[((data[j] & 0x03) << 4) + (data[j + 1] >> 4)];
result += this.toBase64Table[(data[j + 1] & 0x0f) << 2];
result += this.toBase64Table[64];
} else if (lengthpad === 1) {
result += this.toBase64Table[data[j] >> 2];
result += this.toBase64Table[(data[j] & 0x03) << 4];
result += this.toBase64Table[64];
result += this.toBase64Table[64];
}
return result;
},
/* Convert Base64 data to a string */
/* eslint-disable comma-spacing */
toBinaryTable: [
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,-1,
-1,-1,-1,-1, -1,-1,-1,-1, -1,-1,-1,62, -1,-1,-1,63,
52,53,54,55, 56,57,58,59, 60,61,-1,-1, -1, 0,-1,-1,
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,10, 11,12,13,14,
15,16,17,18, 19,20,21,22, 23,24,25,-1, -1,-1,-1,-1,
-1,26,27,28, 29,30,31,32, 33,34,35,36, 37,38,39,40,
41,42,43,44, 45,46,47,48, 49,50,51,-1, -1,-1,-1,-1
],
/* eslint-enable comma-spacing */
decode(data, offset = 0) {
let data_length = data.indexOf('=') - offset;
if (data_length < 0) { data_length = data.length - offset; }
/* Every four characters is 3 resulting numbers */
const result_length = (data_length >> 2) * 3 + Math.floor((data_length % 4) / 1.5);
const result = new Array(result_length);
// Convert one by one.
let leftbits = 0; // number of bits decoded, but yet to be appended
let leftdata = 0; // bits decoded, but yet to be appended
for (let idx = 0, i = offset; i < data.length; i++) {
const c = this.toBinaryTable[data.charCodeAt(i) & 0x7f];
const padding = (data.charAt(i) === this.base64Pad);
// Skip illegal characters and whitespace
if (c === -1) {
Log.Error("Illegal character code " + data.charCodeAt(i) + " at position " + i);
continue;
}
// Collect data into leftdata, update bitcount
leftdata = (leftdata << 6) | c;
leftbits += 6;
// If we have 8 or more bits, append 8 bits to the result
if (leftbits >= 8) {
leftbits -= 8;
// Append if not padding.
if (!padding) {
result[idx++] = (leftdata >> leftbits) & 0xff;
}
leftdata &= (1 << leftbits) - 1;
}
}
// If there are any bits left, the base64 string was corrupted
if (leftbits) {
const err = new Error('Corrupted base64 string');
err.name = 'Base64-Error';
throw err;
}
return result;
}
}; /* End of Base64 namespace */