From 02c2213545d703e3a5861b83e54ffad8cc33c310 Mon Sep 17 00:00:00 2001
From: Wouter Lagerweij <wouter@lagerweij.com>
Date: Sun, 17 Sep 2017 14:27:49 +0200
Subject: [PATCH] Changed rounding to use BigDecimals to avoid noisy long
 doubles in output

---
 .../java/info/nightscout/utils/Round.java     | 52 +++++++------------
 .../java/info/nightscout/utils/RoundTest.java |  3 +-
 2 files changed, 22 insertions(+), 33 deletions(-)

diff --git a/app/src/main/java/info/nightscout/utils/Round.java b/app/src/main/java/info/nightscout/utils/Round.java
index 9cd2ea0acb..a45714ad45 100644
--- a/app/src/main/java/info/nightscout/utils/Round.java
+++ b/app/src/main/java/info/nightscout/utils/Round.java
@@ -7,43 +7,31 @@ import java.math.BigDecimal;
  */
 public class Round {
     public static Double roundTo(Double x, Double step) {
+        return round(x, step, BigDecimal.ROUND_HALF_UP);
+    }
 
-        if (step > 1) {
-            return roundToWhole(x, step);
-        } else {
-            return roundToNrOfDecimals(x, getDecimalsFromStep(step));
-        }
+    public static Double floorTo(Double x, Double step) {
+        return round(x, step, BigDecimal.ROUND_FLOOR);
+    }
+
+    public static Double ceilTo(Double x, Double step) {
+        return round(x, step, BigDecimal.ROUND_CEILING);
+    }
+
+    private static Double round(Double x, Double step, int roundingMode) {
+        BigDecimal numberToRound = new BigDecimal((Double.toString(x)));
+        BigDecimal stepSize = new BigDecimal((Double.toString(step)));
+        int scale = getDecimalsFromStep(step);
+
+        numberToRound.setScale(scale, BigDecimal.ROUND_HALF_UP);
+
+        BigDecimal rounded = numberToRound.divide(stepSize, 0, roundingMode).multiply(stepSize);
+
+        return rounded.doubleValue();
     }
 
     private static int getDecimalsFromStep(Double step) {
         String stepString = Double.toString(step);
         return stepString.substring(stepString.indexOf('.') + 1).length();
     }
-
-    private static Double roundToNrOfDecimals(Double x, int decimals) {
-        BigDecimal number = new BigDecimal(Double.toString(x));
-        number = number.setScale(decimals, BigDecimal.ROUND_HALF_UP);
-
-        return number.doubleValue();
-    }
-
-    private static Double roundToWhole(Double x, Double step) {
-        if (x != 0d) {
-            return Math.round(x / step) * step;
-        }
-        return 0d;
-    }
-
-    public static Double floorTo(Double x, Double step) {
-        if (x != 0d) {
-            return Math.floor(x / step) * step;
-        }
-        return 0d;
-    }
-    public static Double ceilTo(Double x, Double step) {
-        if (x != 0d) {
-            return Math.ceil(x / step) * step;
-        }
-        return 0d;
-    }
 }
diff --git a/app/src/test/java/info/nightscout/utils/RoundTest.java b/app/src/test/java/info/nightscout/utils/RoundTest.java
index d95ab2b391..4ef1be054c 100644
--- a/app/src/test/java/info/nightscout/utils/RoundTest.java
+++ b/app/src/test/java/info/nightscout/utils/RoundTest.java
@@ -14,6 +14,8 @@ public class RoundTest {
     public void roundToTest() throws Exception {
         assertEquals( 0.55d, Round.roundTo(0.54d, 0.05d), 0.00000001d );
         assertEquals( 1d, Round.roundTo(1.49d, 1d), 0.00000001d );
+        assertEquals( 80d, Round.roundTo(65d, 40d), 0.00000001d );
+        assertEquals( 0d, Round.roundTo(0d, 0.1d), 0.00000001d);
     }
 
     @Test
@@ -27,5 +29,4 @@ public class RoundTest {
         assertEquals( 0.6d, Round.ceilTo(0.54d, 0.1d), 0.00000001d );
         assertEquals( 2d, Round.ceilTo(1.49999d, 1d), 0.00000001d );
     }
-
 }
\ No newline at end of file