Class MjpegParser

src/modules/wda-stream/mjpeg.parser.ts:13–97

// Define the class that extends the Transform stream
class MjpegParser extends Transform {
	private buffer: Buffer | null = null;
	private reading: boolean = false;
	private contentLength: number | null = null;
	private bytesWritten: number = 0;

	constructor(options?: TransformOptions) {
		super(options);
	}

	private _initFrame(len: number, chunk: Buffer, start: number, end: number) {
		this.contentLength = len;
		this.buffer = Buffer.alloc(len);
		this.bytesWritten = 0;

		const hasStart = typeof start !== "undefined" && start > -1;
		const hasEnd = typeof end !== "undefined" && end > -1 && end > start;

		if (hasStart) {
			let bufEnd = chunk.length;

			if (hasEnd) {
				bufEnd = end + eoi.length;
			}

			chunk.copy(this.buffer, 0, start, bufEnd);
			this.bytesWritten = chunk.length - start;

			// If we have the EOI bytes, send the frame
			if (hasEnd) {
				this._sendFrame();
			} else {
				this.reading = true;
			}
		}
	}

	private _readFrame(chunk: Buffer, start: number, end: number) {
		const bufStart = start > -1 && start < end ? start : 0;
		const bufEnd = end > -1 ? end + eoi.length : chunk.length;

		chunk.copy(this.buffer!, this.bytesWritten, bufStart, bufEnd);
		this.bytesWritten += bufEnd - bufStart;

		if (end > -1 || this.bytesWritten === this.contentLength) {
			this._sendFrame();
		} else {
			this.reading = true;
		}
	}

	/**
	 * Handle sending the frame to the next stream and resetting state
	 */
	private async _sendFrame() {
		this.reading = false;
		if (this.buffer) {
			sharp(this.buffer)