adamia

I have a new project where I need to parse binary files in Javascript, and it would be very convenient to have the Actionscript ByteArray class. I have ported a big portion of the read() functions from the ByteArray class to a new Javascript class. I did not port any of the write() functions since my current project does not need them, but if there is enough demand I would consider porting them too. The class was written with very high performance in mind. Here is a benchmark against one of the only other Javascript binary decoders I could find:

To use it, just instantiate an a3d.ByteArray() and be sure to supply the two parameters: a string representing the binary data, and an enumeration for endianness of either a3d.Endian.BIG or a3d.Endian.LITTLE. You can fetch a binary file by overriding the mimeType on the XmlHttpRequest as demonstrated in Ilmari Heikkinen's binary parser. Here's an example that assumes jQuery is available:

function log(text) {console.log(text);}

var files = [{filename: 'bigendian.blob', endian: a3d.Endian.BIG, name: 'Big Endian'},
	{filename: 'littleendian.blob', endian: a3d.Endian.LITTLE, name: 'Little Endian'}];
for (var fileIndex in files) {
	var file = files[fileIndex];

	$.ajax({async: false, url: file['filename'], beforeSend: function(xhr) {
		xhr.overrideMimeType('text/plain; charset=x-user-defined');
	}, success: function(data){
		log(file['name']);
						
		var ba = new a3d.ByteArray(data, file['endian']);
		log(ba.readBoolean());
		log(ba.readBoolean());
		log(ba.readByte());
		log(ba.readShort());
		log(ba.readShort());
		log(ba.readUnsignedInt());
		log(ba.readInt());
		log(ba.readInt());
		log(ba.readFloat());
		log(ba.readFloat());
		log(ba.readDouble());
		log(ba.readDouble());
		log(ba.readDouble());
		log(ba.readDouble());
		log(ba.readDouble());
		log(ba.readDouble());
		log('');
	}});
					
}

Parts of the source were originally taken from Ilmari Heikkinen's binary parser.

Here are full source and minified versions: