unPack javascript eval

unPacker.js

//////////////////////////////////////////
//  Un pack the code from the /packer/  //
//  By [email protected]            //
//  http://matthewfl.com/unPacker.html  //
//////////////////////////////////////////
// version 1.2


function unPack (code) {
	function indent (code) {
		try {
		var tabs = 0, old=-1, add='';
		for(var i=0;i<code.length;i++) {
			if(code[i].indexOf("{") != -1) tabs++;
			if(code[i].indexOf("}") != -1) tabs--;
			
			if(old != tabs) {
				old = tabs;
				add = "";
				while (old > 0) {
					add += "\t";
					old--;
				}
				old = tabs;
			}
			
			code[i] = add + code[i];
		}
		} finally {
			tabs = null;
			old = null;
			add = null;
		}
		return code;
	}
    
    var env = {
        eval: function (c) {
            code = c;
        },
        window: {},
        document: {}
    };
    
    eval("with(env) {" + code + "}");
	
	code = (code+"").replace(/;/g, ";\n").replace(/{/g, "\n{\n").replace(/}/g, "\n}\n").replace(/\n;\n/g, ";\n").replace(/\n\n/g, "\n");
	
    code = code.split("\n");
    code = indent(code);
    
    code = code.join("\n");
    return code;
}