junzitang/access/base64.js

export function encode(input) {
	let _keyStr = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
	let chr1, chr2, chr3, enc1, enc2, enc3, enc4, i = 0,
		output = '',
		utftext = '';
	input = input.replace(/\r\n/g, "\n");
	for (let n = 0; n < input.length; n++) {
		let c = input.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);
		}

	}
	while (i < utftext.length) {
		chr1 = utftext.charCodeAt(i++);
		chr2 = utftext.charCodeAt(i++);
		chr3 = utftext.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 +
			_keyStr.charAt(enc1) + _keyStr.charAt(enc2) +
			_keyStr.charAt(enc3) + _keyStr.charAt(enc4);
	}
	return output;
}