Switch to a better PRNG

config.js

@@ -1,18 +1,104 @@
 // TODO These code bits don't really belong here, but this is the only shared bit of js
 
-var randseed = Math.floor(Math.random() * 0xFFFFFFFF);
 
-function Random(n) {
-  return Rand32Rough() % n;
+// From http://baagoe.com/en/RandomMusings/javascript/
+  // Johannes Baagøe <baagoe@baagoe.com>, 2010
+function Mash() {
+  var n = 0xefc8249d;
+
+  var mash = function(data) {
+    data = data.toString();
+    for (var i = 0; i < data.length; i++) {
+      n += data.charCodeAt(i);
+      var h = 0.02519603282416938 * n;
+      n = h >>> 0;
+      h -= n;
+      h *= n;
+      n = h >>> 0;
+      h -= n;
+      n += h * 0x100000000; // 2^32
+    }
+    return (n >>> 0) * 2.3283064365386963e-10; // 2^-32
+  };
+
+  mash.version = 'Mash 0.9';
+  return mash;
 }
 
 
-function Rand32Rough() { 
-  // http://www.merlyn.demon.co.uk/js-randm.htm#MR
-  var T32 = 0x100000000;
-  var constant = 134775813;
-  var X = constant * randseed + 1;
-  return (randseed = X % T32);
+// From http://baagoe.com/en/RandomMusings/javascript/
+function Alea() {
+  return (function(args) {
+    // Johannes Baagøe <baagoe@baagoe.com>, 2010
+    var s0 = 0;
+    var s1 = 0;
+    var s2 = 0;
+    var c = 1;
+    
+    if (args.length == 0) {
+      args = [+new Date];
+    }
+    var mash = Mash();
+    s0 = mash(' ');
+    s1 = mash(' ');
+    s2 = mash(' ');
+    
+    for (var i = 0; i < args.length; i++) {
+      s0 -= mash(args[i]);
+      if (s0 < 0) {
+        s0 += 1;
+      }
+      s1 -= mash(args[i]);
+      if (s1 < 0) {
+        s1 += 1;
+      }
+      s2 -= mash(args[i]);
+      if (s2 < 0) {
+        s2 += 1;
+      }
+    }
+    mash = null;
+    
+    var random = function() {
+      var t = 2091639 * s0 + c * 2.3283064365386963e-10; // 2^-32
+      s0 = s1;
+      s1 = s2;
+      return s2 = t - (c = t | 0);
+    };
+    random.uint32 = function() {
+      return random() * 0x100000000; // 2^32
+    };
+    random.fract53 = function() {
+      return random() + 
+        (random() * 0x200000 | 0) * 1.1102230246251565e-16; // 2^-53
+    };
+    random.version = 'Alea 0.9';
+    random.args = args;
+    random.state = function (newstate) {
+      if (newstate) {
+        s0 = newstate[0];
+        s1 = newstate[1];
+        s2 = newstate[2];
+        c = newstate[3];
+      } else {
+        return [s0,s1,s2,c];
+      }
+    };
+    return random;
+    
+  } (Array.prototype.slice.call(arguments)));
+};
+
+
+var seed = new Alea();
+
+function Random(n) {
+  return seed.uint32() % n;
+}
+
+
+function randseed(set) {
+  return seed.state(set);
 }
 
 
@@ -21,12 +107,12 @@ function Pick(a) {
 }
 
 
-function GenerateName() {
-  var KParts = [
-    'br|cr|dr|fr|gr|j|kr|l|m|n|pr||||r|sh|tr|v|wh|x|y|z',
-    'a|a|e|e|i|i|o|o|u|u|ae|ie|oo|ou',
-    'b|ck|d|g|k|m|n|p|t|v|x|z'];
+var KParts = [
+  'br|cr|dr|fr|gr|j|kr|l|m|n|pr||||r|sh|tr|v|wh|x|y|z'.split('|'),
+  'a|a|e|e|i|i|o|o|u|u|ae|ie|oo|ou'.split('|'),
+  'b|ck|d|g|k|m|n|p|t|v|x|z'.split('|')];
 
+function GenerateName() {
   var result = '';
   for (var i = 0; i <= 5; ++i)
     result += Pick(KParts[i % 3]);