Add @mediabunny/aac-encoder extension package

src/misc.ts

@@ -6,6 +6,8 @@
  * file, You can obtain one at https://mozilla.org/MPL/2.0/.
  */
 
+import { Bitstream } from '../shared/bitstream';
+
 export function assert(x: unknown): asserts x {
 	if (!x) {
 		throw new Error('Assertion failed.');
@@ -39,85 +41,6 @@ export const isU32 = (value: number) => {
 	return value >= 0 && value < 2 ** 32;
 };
 
-export class Bitstream {
-	/** Current offset in bits. */
-	pos = 0;
-
-	constructor(public bytes: Uint8Array) {}
-
-	seekToByte(byteOffset: number) {
-		this.pos = 8 * byteOffset;
-	}
-
-	private readBit() {
-		const byteIndex = Math.floor(this.pos / 8);
-		const byte = this.bytes[byteIndex] ?? 0;
-		const bitIndex = 0b111 - (this.pos & 0b111);
-		const bit = (byte & (1 << bitIndex)) >> bitIndex;
-
-		this.pos++;
-		return bit;
-	}
-
-	readBits(n: number) {
-		if (n === 1) {
-			return this.readBit();
-		}
-
-		let result = 0;
-
-		for (let i = 0; i < n; i++) {
-			result <<= 1;
-			result |= this.readBit();
-		}
-
-		return result;
-	}
-
-	writeBits(n: number, value: number) {
-		const end = this.pos + n;
-
-		for (let i = this.pos; i < end; i++) {
-			const byteIndex = Math.floor(i / 8);
-			let byte = this.bytes[byteIndex]!;
-			const bitIndex = 0b111 - (i & 0b111);
-
-			byte &= ~(1 << bitIndex);
-			byte |= ((value & (1 << (end - i - 1))) >> (end - i - 1)) << bitIndex;
-			this.bytes[byteIndex] = byte;
-		}
-
-		this.pos = end;
-	};
-
-	readAlignedByte() {
-		// Ensure we're byte-aligned
-		if (this.pos % 8 !== 0) {
-			throw new Error('Bitstream is not byte-aligned.');
-		}
-
-		const byteIndex = this.pos / 8;
-		const byte = this.bytes[byteIndex] ?? 0;
-
-		this.pos += 8;
-		return byte;
-	}
-
-	skipBits(n: number) {
-		this.pos += n;
-	}
-
-	getBitsLeft() {
-		return this.bytes.length * 8 - this.pos;
-	}
-
-	clone() {
-		const clone = new Bitstream(this.bytes);
-		clone.pos = this.pos;
-		return clone;
-	}
-}
-
 /** Reads an exponential-Golomb universal code from a Bitstream.  */
 export const readExpGolomb = (bitstream: Bitstream) => {
 	let leadingZeroBits = 0;