PrefixCalculator

'use strict';

angular.module('portal')
  .factory('PrefixCalculator', function () {

    /**
     * Sums up the prefixLengths given a specified bitSize
     * 
     * @param prefixes prefixLength integers (e.g. 22, 39 etc)
     * @param bitSize the bitSize of the IP (e.g. 32 or 128)
     * @returns {number} the total of the prefixLength
     */
    var doSumIpvX = function (prefixes, bitSize) {
      var addressSizes = _.map(prefixes, function (prefix) {
        return Math.pow(2, bitSize - prefix);
      });
      var totalAddressSize = _.reduce(addressSizes, function (total, addressSize) {
        return total + addressSize;
      });
      var sumIpvX = (bitSize - (Math.log(totalAddressSize) / Math.log(2)));
      return Math.floor(sumIpvX);
    };

    return {
      sumIpv4: function (ipv4Prefixes) {
        return doSumIpvX(ipv4Prefixes, 32);
      },
      sumIpv6: function (ipv6Prefixes) {
        return doSumIpvX(ipv6Prefixes, 128);
      }
    };
  });