snapshot of https://github.com/RocketChat/Rocket.Chat.git (develop, 2026-09-16; blobs > 131072B omitted)

packages/base64/src/base64.ts

@@ -0,0 +1,136 @@
+// Base 64 encoding
+
+const BASE_64_CHARS = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
+
+const BASE_64_VALS = Object.create(null);
+
+const getChar = (val: number) => BASE_64_CHARS.charAt(val);
+const getVal = (ch: string) => (ch === '=' ? -1 : BASE_64_VALS[ch]);
+
+for (let i = 0; i < BASE_64_CHARS.length; i++) {
+	BASE_64_VALS[getChar(i)] = i;
+}
+
+const newBinary = (len: number) => new Uint8Array(new ArrayBuffer(len));
+
+const encode = (array: ArrayLike<number> | string) => {
+	if (typeof array === 'string') {
+		const str = array;
+		const binary = newBinary(str.length);
+		for (let i = 0; i < str.length; i++) {
+			const ch = str.charCodeAt(i);
+			if (ch > 0xff) {
+				throw new Error('Not ascii. Base64.encode can only take ascii strings.');
+			}
+
+			binary[i] = ch;
+		}
+		array = binary;
+	}
+
+	const answer: string[] = [];
+	let a: number | null = null;
+	let b: number | null = null;
+	let c: number | null = null;
+	let d: number | null = null;
+
+	for (let i = 0; i < array.length; i++) {
+		switch (i % 3) {
+			case 0:
+				a = (array[i] >> 2) & 0x3f;
+				b = (array[i] & 0x03) << 4;
+				break;
+			case 1:
+				b = (b ?? 0) | ((array[i] >> 4) & 0xf);
+				c = (array[i] & 0xf) << 2;
+				break;
+			case 2:
+				c = (c ?? 0) | ((array[i] >> 6) & 0x03);
+				d = array[i] & 0x3f;
+				answer.push(getChar(a ?? 0));
+				answer.push(getChar(b ?? 0));
+				answer.push(getChar(c));
+				answer.push(getChar(d));
+				a = null;
+				b = null;
+				c = null;
+				d = null;
+				break;
+		}
+	}
+
+	if (a !== null) {
+		answer.push(getChar(a));
+		answer.push(getChar(b ?? 0));
+		if (c === null) {
+			answer.push('=');
+		} else {
+			answer.push(getChar(c));
+		}
+
+		if (d === null) {
+			answer.push('=');
+		}
+	}
+
+	return answer.join('');
+};
+
+const decode = (str: string) => {
+	let len = Math.floor((str.length * 3) / 4);
+	if (str.charAt(str.length - 1) === '=') {
+		len--;
+		if (str.charAt(str.length - 2) === '=') {
+			len--;
+		}
+	}
+
+	const arr = newBinary(len);
+
+	let one: number | null = null;
+	let two: number | null = null;
+	let three: number | null = null;
+
+	let j = 0;
+
+	for (let i = 0; i < str.length; i++) {
+		const c = str.charAt(i);
+		const v = getVal(c);
+		switch (i % 4) {
+			case 0:
+				if (v < 0) {
+					throw new Error('invalid base64 string');
+				}
+
+				one = v << 2;
+				break;
+			case 1:
+				if (v < 0) {
+					throw new Error('invalid base64 string');
+				}
+
+				one = (one ?? 0) | (v >> 4);
+				arr[j++] = one;
+				two = (v & 0x0f) << 4;
+				break;
+			case 2:
+				if (v >= 0) {
+					two = (two ?? 0) | (v >> 2);
+					arr[j++] = two;
+					three = (v & 0x03) << 6;
+				}
+
+				break;
+			case 3:
+				if (v >= 0) {
+					arr[j++] = (three ?? 0) | v;
+				}
+
+				break;
+		}
+	}
+
+	return arr;
+};
+
+export const Base64 = { encode, decode, newBinary };