@phaserjs/phaser
Version:
43 lines (42 loc) • 1.37 kB
JavaScript
/**
* @author Niklas von Hertzen (https://github.com/niklasvh/base64-arraybuffer)
* @author Richard Davey <rich@photonstorm.com>
* @copyright 2020 Photon Storm Ltd.
* @license {@link https://opensource.org/licenses/MIT|MIT License}
*/
let lookup;
export function Base64ToArrayBuffer(base64) {
if (!lookup) {
const chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
lookup = new Uint8Array(256);
for (let i = 0; i < chars.length; i++) {
lookup[chars.charCodeAt(i)] = i;
}
}
base64 = base64.substr(base64.indexOf(",") + 1);
const len = base64.length;
let bufferLength = len * 0.75;
let p = 0;
let encoded1;
let encoded2;
let encoded3;
let encoded4;
if (base64[len - 1] === "=") {
bufferLength--;
if (base64[len - 2] === "=") {
bufferLength--;
}
}
const arrayBuffer = new ArrayBuffer(bufferLength);
const bytes = new Uint8Array(arrayBuffer);
for (let i = 0; i < len; i += 4) {
encoded1 = lookup[base64.charCodeAt(i)];
encoded2 = lookup[base64.charCodeAt(i + 1)];
encoded3 = lookup[base64.charCodeAt(i + 2)];
encoded4 = lookup[base64.charCodeAt(i + 3)];
bytes[p++] = encoded1 << 2 | encoded2 >> 4;
bytes[p++] = (encoded2 & 15) << 4 | encoded3 >> 2;
bytes[p++] = (encoded3 & 3) << 6 | encoded4 & 63;
}
return arrayBuffer;
}