3 * https://github.com/niklasvh/base64-arraybuffer
5 * Copyright (c) 2012 Niklas von Hertzen
6 * Licensed under the MIT license.
11 exports.encode = function(arraybuffer) {
12 var bytes = new Uint8Array(arraybuffer),
13 i, len = bytes.length, base64 = "";
15 for (i = 0; i < len; i+=3) {
16 base64 += chars[bytes[i] >> 2];
17 base64 += chars[((bytes[i] & 3) << 4) | (bytes[i + 1] >> 4)];
18 base64 += chars[((bytes[i + 1] & 15) << 2) | (bytes[i + 2] >> 6)];
19 base64 += chars[bytes[i + 2] & 63];
22 if ((len % 3) === 2) {
23 base64 = base64.substring(0, base64.length - 1) + "=";
24 } else if (len % 3 === 1) {
25 base64 = base64.substring(0, base64.length - 2) + "==";
31 exports.decode = function(base64) {
32 var bufferLength = base64.length * 0.75,
33 len = base64.length, i, p = 0,
34 encoded1, encoded2, encoded3, encoded4;
36 if (base64[base64.length - 1] === "=") {
38 if (base64[base64.length - 2] === "=") {
43 var arraybuffer = new ArrayBuffer(bufferLength),
44 bytes = new Uint8Array(arraybuffer);
46 for (i = 0; i < len; i+=4) {
47 encoded1 = chars.indexOf(base64[i]);
48 encoded2 = chars.indexOf(base64[i+1]);
49 encoded3 = chars.indexOf(base64[i+2]);
50 encoded4 = chars.indexOf(base64[i+3]);
52 bytes[p++] = (encoded1 << 2) | (encoded2 >> 4);
53 bytes[p++] = ((encoded2 & 15) << 4) | (encoded3 >> 2);
54 bytes[p++] = ((encoded3 & 3) << 6) | (encoded4 & 63);
59 })("ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/");