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MangaD · 04-15-2016, 07:22 PM

In response to someone's attempt to read a LF2 data file in JavaScript, I made a simple HTML page for this purpose.

I based myself on @A-Man's explanation for the DC algorithm:

DC Algorithm (Click to View)

Code:
<!DOCTYPE html>

<html>
	<head>
		<title>LF2 - Data Reader</title>
		<meta charset="UTF-8" />
		<meta name="description" content="LF2 data files reader.">
		<meta name="keywords" content="LF2, DC , data, algorithm, file, files, decypher">
		<meta name="author" content="MangaD">

		<link rel="shortcut icon" href="http://www.lf-empire.de/favicon.ico" type="image/x-icon">
		
		<style type="text/css">
			html, body {
				height:100%;
				width:100%;
				border:0;
				margin:0;
				padding: 0;
				text-align:center;
			}
			#main {
				margin-top:30px;
				text-align:initial;
				display:inline-block;
			}
			#DCode {
				width:600px;
				height:400px;
			}
		</style>

		<script type="text/javascript">

			var file;

			function fileSupport() {// Check for the various File API support.
				if (window.File && window.FileReader && window.FileList && window.Blob) {
					// Great success! All the File APIs are supported.
				} else {
					alert('The File APIs are not fully supported in this browser.');
				}
			}

			function openFile() {
				file = document.getElementById("fileInput").files[0];
				var fileName = escape(file.name);
				var fileType = (file.type ? file.type : 'n/a');
				var fileSize = file.size;
				var lastModified = file.lastModifiedDate ? file.lastModifiedDate.toLocaleDateString() : 'n/a';
				
				if(file.name.substring(file.name.lastIndexOf(".")) != ".dat" ) {
					alert('LF2 data file only.');
					return false;
				}
				else {
					fileType = "LF2/data";
				}
				document.getElementById('details').innerHTML = 
					'<strong>' + fileName + '</strong> (' + fileType + ') - ' +
					fileSize + ' bytes, last modified: ' + lastModified;
				return true;
			}
			
			function decrypt() {
				var key = "odBearBecauseHeIsVeryGoodSiuHungIsAGo";
				var reader = new FileReader();
				
				reader.onload = function(){
					var data = reader.result;
					var text = "";
					
					for (var i = 123, j = 0; i < data.length; i++, j++)
						text += String.fromCharCode(data.charCodeAt(i) - key.charCodeAt(j%key.length));
					
					document.getElementById('DCode').innerHTML = text;
				};
				
				reader.readAsBinaryString(file);
			}
		</script>
	</head>
	
	<body onload="fileSupport();">
		<div id="main">
			<label for="fileInput">Open .dat file:</label>
			<br>
			<input id="fileInput" type="file" onchange="if(openFile()) decrypt();">
			<br>
			<output id="details"></output>
			<br>
			<textarea id="DCode" wrap='off'></textarea>
		</div>
	</body>
</html>

Download file here.

Hydroper · (This post was last modified: 04-15-2016, 07:45 PM by Hydroper.)

Thanks for answering, man.

I'm not sure, but I think the problem I couldn't read the file as well before is because I'm just calling a function with a argument of string, where I use a string with the binary content of the criminal.dat, but I don't use XMLHttpRequest or any other thing to get the file content... I just paste it.

Your code works as well! You can change the line to make the loop more faster, though.

Code:
for (var i = 123, j = 0; i < data.length; i++, j++)

to

Code:
for (var i = 123, j = 0, len = data.length; i < len; i++, j++)

(Because, in JavaScript, the for numeral loop limit is always calculated, then the data string length will be calculated everytime, also.)

empirefantasy · 04-15-2016, 08:07 PM

great!

actually i have been thinking sometimes ago to make an online IDE.

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