map = mmap(comedi_stuff)
int buffer_size = size_of_comedi_buffer();
int front = 0;
int back = 0;
int num_channels = number_of_channels;
int max_samples; //max number of samples we can ship over earthworm

while(true) {
  front+=comedi_get_buffer_contents();
  while(front==back) {
    sleep;
    front+=comedi_get_buffer_contents();
  }

  endtime = gettimeofday();
  num_samples = (front-back)/(num_channels*sizeof(sample));
  begintime = calc_begin_time(endtime, num_samples);

  int t_chan=0; //lets us know where to put the data
  for(i=back;i<front;i+=sizeof(sampl) {
    sampl_t read = *(sampl_t *)(map+i%buffer_size);
    
    int data_pos = channel_trace[t_chan].data_pos++;
    channel_trace[t_chan].data[data_pos] = read;

    //need to ship the trace early if we've read more out of the buffer
    //than can be sent via the earthw transport rings
    if(data_pos==max_samples){
      ship_it(channel_trace[t_chan]);
    }

    if(t_chan==(num_channels-1)) {
      t_chan = 0;
    } else {
      t_chan++;
    }
  }
  
  for(i=0;i<num_channels;i++) {
    ship_it(channel_trace[i]);
  }

  comedi_mark_buffer_read(front-back);
  front = front%buffer_size;  //do this so we don't exceed the max size of int
  back = front;
}