C#

<br />
int x; % foo<br />
% bar<br />
x = 5; %x = 5<br />

buffer:    what it can be:
'i'          int or ident
'in'         int or ident
'int'        int or ident
'int '       nothing. Go back 1 letter
'int'        first rule that fits is keyword int, so it's int
' '          fits nothing from beggining, so ignore it
'x'          fits ident
'x '         fits nothing, go back
...

// a console app
static void Main(string[] args)
{
  StringBuilder sb = new StringBuilder(16384);
  for (int i = 0; i < 10000; i++)
     sb.AppendLine(String.Format("{0:HH:mm:ss.ffff}", DateTime.Now));

  Console.WriteLine(sb.ToString());
  Console.ReadLine();
}

static void Main(string[] args)
{
  StringBuilder sb = new StringBuilder(16384);
  Stopwatch sw = new Stopwatch(); sw.Start();
  DateTime now = DateTime.Now;
  for (int i = 0; i < 10000; i++)
     sb.AppendLine(String.Format("{0:HH:mm:ss.fffff}", now + sw.Elapsed));

  Console.WriteLine(sb.ToString());
  Console.ReadLine();
}

// in your background thread
int msToWait = 5000;

do {

  // wait for Start event
  manualStartEvent.WaitOne(); 

  Stopwatch sw = new Stopwatch();
  sw.Start();
  // wait for Pause event, or until time elapses
  bool externalSet = manualPauseEvent.WaitOne(msToWait);
  sw.Stop();

  // check if Paused or elapsed
  int actualMsElapsed = sw.Elapsed.TotalMilliseconds;
  if (externalSet) // this indicates external set, so time did not elapse
  {  
    msToWait -= actualMsElapsed;
    if (msToWait < 0)
       msToWait = 0;
  }
  else // this indicates we're done
  {
    msToWait = 0;
  }

} while (msToWait > 0);