From: PJ Fanning <fanningpj@apache.org>
Date: Tue, 20 Oct 2020 16:07:10 +0000 (+0000)
Subject: [github-193] Change TRUNC implementation to use MathX. Thanks to Jacob Harris. This... 
X-Git-Tag: before_ooxml_3rd_edition~93
X-Git-Url: https://source.dussan.org/?a=commitdiff_plain;h=dd9f132c232c24d939adba5065280fbba0e4ed42;p=poi.git

[github-193] Change TRUNC implementation to use MathX. Thanks to Jacob Harris. This closes #193

git-svn-id: https://svn.apache.org/repos/asf/poi/trunk@1882706 13f79535-47bb-0310-9956-ffa450edef68
---

diff --git a/src/java/org/apache/poi/ss/formula/functions/NumericFunction.java b/src/java/org/apache/poi/ss/formula/functions/NumericFunction.java
index 1927848555..87646295bd 100644
--- a/src/java/org/apache/poi/ss/formula/functions/NumericFunction.java
+++ b/src/java/org/apache/poi/ss/formula/functions/NumericFunction.java
@@ -330,9 +330,7 @@ public abstract class NumericFunction implements Function {
 			try {
 				double d0 = singleOperandEvaluate(arg0, srcRowIndex, srcColumnIndex);
 				double d1 = singleOperandEvaluate(arg1, srcRowIndex, srcColumnIndex);
-				double multi = Math.pow(10d,d1);
-				if(d0 < 0) result = -Math.floor(-d0 * multi) / multi;
-                else result = Math.floor(d0 * multi) / multi;
+				result = MathX.roundDown(d0, (int)d1);
 				checkValue(result);
 			}catch (EvaluationException e) {
 				return e.getErrorEval();
diff --git a/src/testcases/org/apache/poi/ss/formula/functions/TestTrunc.java b/src/testcases/org/apache/poi/ss/formula/functions/TestTrunc.java
index a501435616..c8f4d90f5f 100644
--- a/src/testcases/org/apache/poi/ss/formula/functions/TestTrunc.java
+++ b/src/testcases/org/apache/poi/ss/formula/functions/TestTrunc.java
@@ -57,6 +57,21 @@ public final class TestTrunc extends BaseTestNumeric {
 		assertEquals("TRUNC", (new NumberEval(2.612d)).getNumberValue(), ((NumberEval)result).getNumberValue());
 	}
 
+	@Test
+	public void testTruncWithProblematicDecimalNumber() {
+		ValueEval[] args = { new NumberEval(0.29), new NumberEval(2) };
+		ValueEval result = NumericFunction.TRUNC.evaluate(args, -1, (short)-1);
+		assertEquals("TRUNC", (new NumberEval(0.29d)).getNumberValue(), ((NumberEval)result).getNumberValue());
+	}
+
+	@Test
+	public void testTruncWithProblematicCalculationResult() {
+
+		ValueEval[] args = { new NumberEval(21.624d / 24d + .009d), new NumberEval(2) };
+		ValueEval result = NumericFunction.TRUNC.evaluate(args, -1, (short)-1);
+		assertEquals("TRUNC", (new NumberEval(0.91d)).getNumberValue(), ((NumberEval)result).getNumberValue());
+	}
+
 	@Test
 	public void testTruncWithDecimalNumberOneArg() {
 		ValueEval[] args = { new NumberEval(2.612777) };