forgot that 4 of them were git repos :skull

games/webEPK/EPKDecompiler.js

@@ -0,0 +1,256 @@
+window.decompileEPK = function() {
+	let currentOffset = 0;
+
+	let numFiles = 0;
+
+	let onfile = function() {};
+
+	function detectOldHeader(epkData) {
+		const oldHeader = "EAGPKG!!";
+		for (let i = 0; i < oldHeader.length; i++) {
+			if (epkData[i] != oldHeader.charCodeAt(i)) return false;
+		}
+		return true;
+	}
+
+	function readASCII(epkData) {
+		const len = read(epkData);
+		let str = "";
+		for (let i = 0; i < len; i++) {
+			str += String.fromCharCode(read(epkData));
+		}
+		return str;
+	}
+
+	function read(epkData) {
+		return epkData[currentOffset++];
+	}
+
+	function skip(num) {
+		currentOffset += num;
+	}
+
+	function loadShort(epkData) {
+		return (read(epkData) << 8) | read(epkData);
+	}
+
+	function loadInt(epkData) {
+		return (read(epkData) << 24) | (read(epkData) << 16) | (read(epkData) << 8) | read(epkData);
+	}
+
+	function readUTF(epkData) {
+		const len = loadShort(epkData);
+		let str = "";
+		for (let i = 0; i < len; i++) {
+			str += String.fromCharCode(read(epkData));
+		}
+		return str;
+	}
+
+	// https://stackoverflow.com/a/18639903/6917520
+
+	const crc32 = (function() {
+		let table = new Uint32Array(256);
+
+		for (let i = 256; i--;) {
+			let tmp = i;
+
+			for (let k = 8; k--;) {
+				tmp = tmp & 1 ? 3988292384 ^ tmp >>> 1 : tmp >>> 1;
+			}
+
+			table[i] = tmp;
+		}
+
+		return function(data) {
+			let crc = -1;
+
+			for (let i = 0, l = data.length; i < l; i++) {
+				crc = crc >>> 8 ^ table[crc & 255 ^ data[i]];
+			}
+
+			return (crc ^ -1) >>> 0;
+		};
+	})();
+
+	function decompileOld(epkData) {
+		readUTF(epkData);
+
+		try {
+			let zData = pako.inflate(epkData.slice(currentOffset));
+			currentOffset = 0;
+			return readFilesOld(zData);
+		} catch (err) {
+			return null;
+		}
+	}
+
+	function decompileNew(epkData) {
+		const vers = readASCII(epkData);
+		
+		if (!vers.startsWith("ver2.")) {
+			return null;
+		}
+
+		skip(read(epkData));
+		skip(loadShort(epkData));
+		skip(8);
+
+		numFiles = loadInt(epkData);
+
+		const compressionType = String.fromCharCode(read(epkData));
+
+		let zData = epkData.slice(currentOffset);
+		
+		if (compressionType == "Z" || compressionType == "G") {
+			try {
+				zData = pako.inflate(zData);
+			} catch (err) {
+				return null;
+			}
+		} else if (compressionType == "0") {
+			// do nothing
+		} else {
+			return null;
+		}
+
+		currentOffset = 0;
+
+		return readFilesNew(zData);
+	}
+
+	function readFilesOld(data) {
+		let files = [];
+
+		let file;
+		while ((file = readFileOld(data)) != null) {
+			if (file == -1) return null;
+			files.push(file);
+			onfile();
+		}
+
+		onfile = function() {};
+
+		return files;
+	}
+
+	function readFileOld(data) {
+		const s = readUTF(data);
+		if (s == " end") {
+			return null;
+		} else if (s != "<file>") {
+			return -1;
+		}
+
+		const path = readUTF(data);
+
+		skip(20);
+
+		const len = loadInt(data);
+		const blob = new Blob([data.slice(currentOffset, currentOffset + len)]);
+		skip(len);
+		if (readUTF(data) != "</file>") {
+			return -1;
+		}
+
+		return {
+			type: "FILE",
+			name: path,
+			data: blob
+		};
+	}
+
+	function readFilesNew(data) {
+		let files = [];
+
+		let file;
+		while ((file = readFileNew(data)) != null) {
+			if (file == -1) return null;
+			files.push(file);
+			onfile();
+		}
+
+		onfile = function() {};
+
+		return files;
+	}
+
+	function readFileNew(data) {
+		const type = String.fromCharCode(read(data), read(data), read(data), read(data));
+
+		if (numFiles == 0) {
+			if (type != "END$") {
+				return -1;
+			}
+			return null;
+		}
+
+		if (type == "END$") {
+			return -1;
+		}
+
+		const name = readASCII(data);
+		const len = loadInt(data);
+		let blob = null;
+
+		if (type == "FILE") {
+			if (len < 5) {
+				return -1;
+			}
+
+			const crc = loadInt(data);
+			const blobBuffer = data.slice(currentOffset, currentOffset + len - 5);
+			skip(len - 5);
+			blob = new Blob([blobBuffer]);
+
+			if (crc != (crc32(blobBuffer) | 0)) {
+				return -1;
+			}
+
+			if (read(data) != 58) {
+				return -1;
+			}
+		} else {
+			blob = new Blob([data.slice(currentOffset, currentOffset + len)]);
+			skip(len);
+		}
+
+		if (read(data) != 62) {
+			return -1;
+		}
+
+		numFiles--;
+
+		return {
+			type: type,
+			name: name,
+			data: blob
+		};
+	}
+
+	return async function(rawBuffer, fileev) {
+		if (fileev != null) {
+			onfile = fileev;
+		}
+
+		let epkData = new Uint8Array(rawBuffer);
+
+		if (detectOldHeader(epkData)) {
+			epkData = epkData.slice(8);
+			return decompileOld(epkData);
+		}
+
+		const header = "EAGPKG$$";
+		for (let i = 0; i < header.length; i++) {
+			if (epkData[i] != header.charCodeAt(i)) return null;
+		}
+
+		const endCode = ":::YEE:>";
+		for (let i = 0; i < endCode.length; i++) {
+			if (epkData[epkData.length - 8 + i] != endCode.charCodeAt(i)) return null;
+		}
+
+		epkData = epkData.slice(8, -8);
+		return decompileNew(epkData);
+	};
+};