playcanvas/build/playcanvas/src/framework/handlers/untar.js

Open-source WebGL/WebGPU 3D engine for the web

import { EventHandler } from "../../core/event-handler.js";
class Untar extends EventHandler {
	headerSize = 512;
	paddingSize = 512;
	bytesRead = 0;
	bytesReceived = 0;
	headerRead = false;
	reader = null;
	data = new Uint8Array(0);
	decoder = null;
	prefix = "";
	fileName = "";
	fileSize = 0;
	fileType = "";
	ustarFormat = "";
	constructor(fetchPromise, assetsPrefix = "") {
		super();
		this.prefix = assetsPrefix || "";
		this.reader = fetchPromise.body.getReader();
		this.reader.read().then((res) => {
			this.pump(res.done, res.value);
		}).catch((err) => {
			this.fire("error", err);
		});
	}
	pump(done, value) {
		if (done) {
			this.fire("done");
			return null;
		}
		this.bytesReceived += value.byteLength;
		const data = new Uint8Array(this.data.length + value.length);
		data.set(this.data);
		data.set(value, this.data.length);
		this.data = data;
		while (this.readFile()) ;
		return this.reader.read().then((res) => {
			this.pump(res.done, res.value);
		}).catch((err) => {
			this.fire("error", err);
		});
	}
	readFile() {
		if (!this.headerRead && this.bytesReceived > this.bytesRead + this.headerSize) {
			this.headerRead = true;
			const view = new DataView(this.data.buffer, this.bytesRead, this.headerSize);
			this.decoder ?? (this.decoder = new TextDecoder("windows-1252"));
			const headers = this.decoder.decode(view);
			this.fileName = headers.substring(0, 100).replace(/\0/g, "");
			this.fileSize = parseInt(headers.substring(124, 136), 8);
			this.fileType = headers.substring(156, 157);
			this.ustarFormat = headers.substring(257, 263);
			if (this.ustarFormat.indexOf("ustar") !== -1) {
				const prefix = headers.substring(345, 500).replace(/\0/g, "");
				if (prefix.length > 0) {
					this.fileName = prefix.trim() + this.fileName.trim();
				}
			}
			this.bytesRead += 512;
		}
		if (this.headerRead) {
			if (this.bytesReceived < this.bytesRead + this.fileSize) {
				return false;
			}
			if (this.fileType === "" || this.fileType === "0") {
				const dataView = new DataView(this.data.buffer, this.bytesRead, this.fileSize);
				const file = {
					name: this.prefix + this.fileName,
					size: this.fileSize,
					data: dataView
				};
				this.fire("file", file);
			}
			this.bytesRead += this.fileSize;
			this.headerRead = false;
			const bytesRemained = this.bytesRead % this.paddingSize;
			if (bytesRemained !== 0) {
				this.bytesRead += this.paddingSize - bytesRemained;
			}
			return true;
		}
		return false;
	}
}
export {
	Untar
};