A modified version of parseRange in connectjs to deal with range requests of the form bytes=a-b, c-d where a,b,c and d are all numbers, and while a < b and c < d, there is not necessarily a correspondence between a and c or b and d.

Bastardisation of rangeCheck in connect lib util.js

exports.parseRange = function(size, str){
  var valid = true;
  console.log('Requested range: ' + str);
  var arr = str.substr(6).split(',').map(function(range){
	console.log(range);
    var range = range.split('-')
      , start = parseInt(range[0], 10)
      , end = parseInt(range[1], 10);

    // -500
    if (isNaN(start)) {
      start = size - end;
      end = size - 1;
    // 500-
    } else if (isNaN(end)) {
      end = size - 1;
    }

    // Invalid
    if (isNaN(start) || isNaN(end) || start > end || start < 0) {
	valid = false;
    }

    return {
      start: start,
      end: end
    };
  });

  if (valid) {
	if (arr.length > 1) {
	  return [ { 
		start: 	Math.min(arr[0].start, arr[1].start),
		end:	Math.max(arr[0].end, arr[1].end)
	  } ];
	} else {
	  return arr;
	}
  } else {
    return null;
  }
};