randomutil.js

Some functions/methods for random numbers, really just for testing support.

• ¶

  define(["util", "whrandom"], function (util, RandomStream) {
  
    var Randomizer = util.Class({
      constructor: function (seed) {
        this.stream = RandomStream(seed);
      },
      number: function (max) {
        return Math.floor(this.stream() * max);
      },
      pick: function (seq) {
        return seq[this.number(seq.length)];
      },
      pickDist: function (items) {
        var total = 0;
        for (var a in items) {
          if (! items.hasOwnProperty(a)) {
            continue;
          }
          if (typeof items[a] != "number") {
            throw "Bad property: " + a + " not a number";
          }
          total += items[a];
        }
        var num = this.number(total);
        var last;
        for (a in items) {
          if (! items.hasOwnProperty(a)) {
            continue;
          }
          last = a;
          if (num < items[a]) {
            return a;
          }
          num -= items[a];
        }

• ¶

  FIXME: not sure if this should ever h

        return last;
      },
      string: function (len, chars) {
        var s = "";
        for (var i=0; i<len; i++) {
          s += this.character(chars);
        }
        return s;
      },
      character: function (chars) {
        chars = chars || this.defaultChars;
        return chars.charAt(this.number(chars.length));
      }
    });
  
    Randomizer.prototype.lower = "abcdefghijklmnopqrstuvwxyz";
    Randomizer.prototype.upper = Randomizer.prototype.lower.toUpperCase();
    Randomizer.prototype.numberCharacters = "0123456789";
    Randomizer.prototype.whitespace = " \t\n";
    Randomizer.prototype.punctuation = "~`!@#$%^&*()_-+={}[]|\\;:'\"<>,./?";
    Randomizer.prototype.defaultChars =
        Randomizer.prototype.lower + Randomizer.prototype.upper +
        Randomizer.prototype.numberCharacters + Randomizer.prototype.whitespace +
        Randomizer.prototype.punctuation;
  
    return Randomizer;
  });