(function () {
'use strict';

var input = process.argv[2];
var fs = require('fs');
var nb = fs.readFileSync(input, null);

var ab = nb.buffer.slice(nb.byteOffset, nb.byteOffset + nb.byteLength)
var dv = new DataView(ab);

//
// read header
//
console.log('');
console.log('//////////////////');
console.log('//    HEADER    //');
console.log('//////////////////');
console.log('');

console.log('id (int)', dv.getUint16(0));

var i = dv.getUint16(2, false);
console.log('header 0x', i.toString(16));
var flagsstr = ''
	+ 'qr ' + ((i & 0x8000) >> 15) + ', '
  + 'opcode ' + ((i & 0x7800) >> 11) + ', '
  + 'aa ' + ((i &  0x400) >> 10) + ', '
  + 'tc ' + ((i &  0x200) >>  9) + ', '
  + 'rd ' + ((i &  0x100) >>  8) + ', '
  + 'ra ' + ((i &   0x80) >>  7) + ', '
  + 'res1 ' + ((i &   0x40) >>  6) + ', '
  + 'res2 ' + ((i &   0x20) >>  5) + ', '
  + 'res3 ' + ((i &   0x10) >>  4) + ', '
  + 'rcode ' + ((i &    0xF));
console.log('(flags: ' + flagsstr);

var qdcount = dv.getUint16(4, false);  // query count
var ancount = dv.getUint16(6, false);  // answer count
var nscount = dv.getUint16(8, false);  // authority count
var arcount = dv.getUint16(10, false); // additional count

console.log('qdcount', qdcount);
console.log('ancount', ancount);
console.log('nscount', nscount);
console.log('arcount', arcount);

console.log('');
console.log('//////////////////');
console.log('//   QUESTION   //');
console.log('//////////////////');
console.log('');


}());