From 502d5996b66af93af562e2ae58f625c26d83145c Mon Sep 17 00:00:00 2001
From: Dan Vanderkam <danvk@google.com>
Date: Fri, 15 Jul 2011 16:27:45 -0400
Subject: [PATCH] Division by zero bug fix and regression test

---
 auto_tests/misc/local.html      |  1 +
 auto_tests/tests/custom_bars.js | 59 +++++++++++++++++++++++++++++++++++++++++
 dygraph.js                      | 10 ++++---
 3 files changed, 67 insertions(+), 3 deletions(-)
 create mode 100644 auto_tests/tests/custom_bars.js

diff --git a/auto_tests/misc/local.html b/auto_tests/misc/local.html
index 74e308e..881c10f 100644
--- a/auto_tests/misc/local.html
+++ b/auto_tests/misc/local.html
@@ -24,6 +24,7 @@
   <script type="text/javascript" src="../tests/to_dom_coords.js"></script>
   <script type="text/javascript" src="../tests/interaction_model.js"></script>
   <script type="text/javascript" src="../tests/scrolling_div.js"></script>
+  <script type="text/javascript" src="../tests/custom_bars.js"></script>
   <script type="text/javascript">
   var tc = null;
   function processVariables() {
diff --git a/auto_tests/tests/custom_bars.js b/auto_tests/tests/custom_bars.js
new file mode 100644
index 0000000..e55b1c8
--- /dev/null
+++ b/auto_tests/tests/custom_bars.js
@@ -0,0 +1,59 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+
+/**
+ * @fileoverview Regression test based on some strange customBars data.
+ * @author danvk@google.com (Dan Vanderkam)
+ */
+var CustomBarsTestCase = TestCase("custom-bars");
+
+CustomBarsTestCase.prototype.setUp = function() {
+  document.body.innerHTML = "<div id='graph'></div>";
+};
+
+CustomBarsTestCase.prototype.tearDown = function() {
+};
+
+// This test used to reliably produce an infinite loop.
+CustomBarsTestCase.prototype.testCustomBarsNoHang = function() {
+  var opts = {
+    width: 480,
+    height: 320,
+    customBars: true
+  };
+  var data = "X,Y1,Y2\n" +
+    "1,1178.0;1527.5;1856.6,0;22365658;0\n" +
+    "2,1253.0;1303.3;1327.3,0;22368228;0\n" +
+    "3,878.0;1267.0;1357.1,0;22368895;0\n" +
+    "4,1155.0;1273.1;1303.5,0;22369665;0\n" +
+    "5,1089.0;1294.8;1355.3,0;22370160;0\n" +
+    "6,1088.0;1268.6;1336.1,0;22372346;0\n" +
+    "7,1141.0;1269.1;1301.2,0;22373318;0\n" +
+    "8,1072.0;1255.8;1326.2,0;22374310;0\n" +
+    "9,1209.0;1309.2;1351.8,0;22374924;0\n" +
+    "10,1230.0;1303.9;1332.6,0;22380163;0\n" +
+    "11,1014.0;1263.5;1330.8,0;22381117;0\n" +
+    "12,853.0;1215.6;1330.6,0;22381556;0\n" +
+    "13,1134.0;1581.9;1690.1,0;22384631;0\n" +
+    "14,1113.0;1540.1;1676.5,0;22386933;0\n" +
+    "15,1130.0;1542.7;1678.3,0;22393459;0\n" +
+    "18,1582.0;1644.4;1690.2,0;22395914;0\n" +
+    "19,878.0;1558.3;1708.1,0;22397732;0\n" +
+    "20,1076.0;1598.4;1723.8,0;22397886;0\n" +
+    "21,1077.0;1574.0;1685.3,0;22398659;0\n" +
+    "22,1118.0;1590.4;1697.6,0;22399009;0\n" +
+    "23,1031.0;1473.1;1644.9,0;22401969;0\n" +
+    "24,1090.0;1480.7;1640.0,0;22417989;0\n" +
+    "25,1592.0;1681.7;1714.4,0;22422819;0\n" +
+    "26,1251.0;1657.8;1750.6,0;22423681;0\n" +
+    "27,1144.0;1660.9;1776.2,0;22426947;0\n" +
+    "28,1178.0;1642.4;1745.6,0;22428238;0\n" +
+    "29,1169.0;1649.1;1757.5,0;22429524;0\n" +
+    "30,1150.0;1596.1;1746.7,0;22433472;0\n" +
+    "31,1099.0;1586.5;1732.8,0;22434308;0\n" +
+    "32,1120.0;1456.0;1620.3,0;22434821;0\n" +
+    "33,1640.0;1687.7;1709.0,0;22434882;0\n" +
+    "34,1671.0;1712.1;1733.7,0;22435116;0\n" +
+    "35,,0;22437620;0\n";
+  var graph = document.getElementById("graph");
+  var g = new Dygraph(graph, data, opts);
+};
diff --git a/dygraph.js b/dygraph.js
index 2619d63..4404a97 100644
--- a/dygraph.js
+++ b/dygraph.js
@@ -2410,9 +2410,13 @@ Dygraph.prototype.rollingAverage = function(originalData, rollPeriod) {
           count -= 1;
         }
       }
-      rollingData[i] = [originalData[i][0], [ 1.0 * mid / count,
-                                              1.0 * (mid - low) / count,
-                                              1.0 * (high - mid) / count ]];
+      if (count) {
+        rollingData[i] = [originalData[i][0], [ 1.0 * mid / count,
+                                                1.0 * (mid - low) / count,
+                                                1.0 * (high - mid) / count ]];
+      } else {
+        rollingData[i] = [originalData[i][0], [null, null, null]];
+      }
     }
   } else {
     // Calculate the rolling average for the first rollPeriod - 1 points where
-- 
2.7.4