var RRDManager function rrdFile this rrdFile rrdFile This function ret

var RRDManager = function(rrdFile) {
  this.rrdFile = rrdFile;
};

/*
This function returns an object outputData of following format:
outputData = {
  dsNames : [{
    CFVariants : [[timestamp, value]]
  }]
}
*/

RRDManager.prototype.getData = function(timeFrom, timeTo) {
  if (timeFrom > timeTo || lastUpdate < timeFrom) return {};
  var CFVariants = this.getCFVariants();
  var rraArchives = this.getRRAs();
  var lastUpdate = this.rrdFile.getLastUpdate();
  var dsNames = this.rrdFile.getDSNames();

  var outputData = {};
  for (var i = 0, len = dsNames.length; i < len; i++) {
    outputData[dsNames[i]] = {};
    var dataByDsName = outputData[dsNames[i]];
    for (var j = 0, CFCount = CFVariants.length; j < CFCount; j++) {
      dataByDsName[CFVariants[j]] = {};
    }
  }

  var fittedArchives = this.getFittedArchives(rraArchives, timeFrom);

  for (var i = 0, CFNumber = CFVariants.length; i < CFNumber; i++) {
    var currentArchive = fittedArchives[i];
    for (var j = 0, dsNumber = dsNames.length; j < dsNumber; j++) {
      outputData[dsNames[j]][CFVariants[i]] = [];
      var startIndex = (currentArchive.row_cnt - 1) - (lastUpdate - timeFrom)/currentArchive.getStep();
      var endIndex = (lastUpdate - timeTo > 0)
          ? currentArchive.row_cnt - (lastUpdate - timeTo)/currentArchive.getStep();
          : currentArchive.row_cnt;
      var startIndex = (lastUpdate - timeFrom > 0)
          ? (currentArchive.row_cnt*(1 - (lastUpdate - timeFrom)/this.calculateMaxTimeBack(currentArchive)))
          : currentArchive.row_cnt;
      var endIndex = (lastUpdate - timeTo > 0)
          ? (currentArchive.row_cnt*(lastUpdate - timeFrom)/this.calculateMaxTimeBack(currentArchive))
          : currentArchive.row_cnt;
      for (var k = startIndex; i < endIndex; i++) {
        outputData[dsNames[j]][CFVariants[i]].push([lastUpdate - this.calculateTimeBack(currentArchive, k), currentArchive.getEl(k, j)]);
      }
    }
  }

  return outputData;
}

RRDManager.prototype.getFittedArchives = function(archives, timeFrom) {
  var lastUpdate = this.rrdFile.getLastUpdate();
  var CFVariantsNumber = this.getCFVariants().length;
  var output = [];
  for (var i = 0, len = archives.length; i < len; i += CFVariantsNumber) {
    if (this.calculateMaxTimeBack(archives[i]) >= timeFrom) continue;
    for (var j = 0; j < CFVariantsNumber; j++) {
      output.push(archives[i + j]);
    }
    return output;
  }

  for (var j = 0; j < CFVariantsNumber; j++) {
    output.push(archives[len - CFVariantsNumber + j]);
  }
  return output;
}

RRDManager.prototype.getCFVariants = function() {
  var CFVariants = [];
  for (var i = 0, cnt = this.rrdFile.getNrRRAs(); i < cnt; i++) {
    var CFName = this.rrdFile.getRRA(i).rra_info.getCFName();
    if (CFVariants.indexOf(CFName) === -1) CFVariants.push(CFName);
  }
  return CFVariants;
}

RRDManager.prototype.getRRAs = function() {
  var RRAs = [];
  for (var i = 0, cnt = this.rrdFile.getNrRRAs(); i < cnt; i++) {
    RRAs.push(this.rrdFile.getRRA(i));
  }
  return RRAs;
}

RRDManager.prototype.calculateMaxTimeBack = function(RRA) {
  return RRA.getStep()*RRA.row_cnt;
}

RRDManager.prototype.calculateTimeBack = function(RRA, row_index) {
  return RRA.getStep()*row_index;
}