From 4b2fe1385316c47b4c48aad18d2c419ac5ccb227 Mon Sep 17 00:00:00 2001
From: ask <ask@lazarus-ide.org>
Date: Mon, 24 Sep 2012 14:37:53 +0000
Subject: [PATCH] TAChart: Add IsEquivalent utility function

git-svn-id: trunk@38811 -
---
 components/tachart/tachartutils.pas   |  6 ++++++
 components/tachart/test/UtilsTest.pas | 11 +++++++++++
 2 files changed, 17 insertions(+)

diff --git a/components/tachart/tachartutils.pas b/components/tachart/tachartutils.pas
index 17cc372c22..1dbb55275e 100644
--- a/components/tachart/tachartutils.pas
+++ b/components/tachart/tachartutils.pas
@@ -293,6 +293,7 @@ function FormatIfNotEmpty(AFormat, AStr: String): String; inline;
 function IfThen(ACond: Boolean; ATrue, AFalse: TObject): TObject; overload;
 function InterpolateRGB(AColor1, AColor2: Integer; ACoeff: Double): Integer;
 function IntToColorHex(AColor: Integer): String; inline;
+function IsEquivalent(const A1, A2: Double): Boolean; inline;
 function IsNan(const APoint: TDoublePoint): Boolean; overload; inline;
 function NumberOr(ANum: Double; ADefault: Double = 0.0): Double; inline;
 
@@ -424,6 +425,11 @@ begin
     Result := '$' + IntToHex(AColor, 6);
 end;
 
+function IsEquivalent(const A1, A2: Double): Boolean;
+begin
+  Result := CompareDWord(A1, A2, SizeOf(A1) div SizeOf(DWord)) = 0;
+end;
+
 function IsNan(const APoint: TDoublePoint): Boolean;
 begin
   Result := IsNan(APoint.X) or IsNan(APoint.Y);
diff --git a/components/tachart/test/UtilsTest.pas b/components/tachart/test/UtilsTest.pas
index 27bac26c2d..260e003434 100644
--- a/components/tachart/test/UtilsTest.pas
+++ b/components/tachart/test/UtilsTest.pas
@@ -40,6 +40,7 @@ type
   TMathTest = class(TTestCase)
   published
     procedure CumulNurmDistrTest;
+    procedure TestIsEquivalent;
   end;
 
   TGeometryTest = class(TTestCase)
@@ -172,6 +173,16 @@ begin
     AssertEquals(p, InvCumulNormDistr(CumulNormDistr(p)));
 end;
 
+procedure TMathTest.TestIsEquivalent;
+begin
+  AssertTrue(IsEquivalent(1.2345, 1.2345));
+  AssertTrue(IsEquivalent(SafeNaN, SafeNaN));
+  AssertTrue(IsEquivalent(1e100, 1e100+1));
+  AssertFalse(IsEquivalent(1e10, 1e10+1));
+  AssertFalse(IsEquivalent(5, SafeNaN));
+  AssertFalse(IsEquivalent(SafeNaN, 5));
+end;
+
 { TGeometryTest }
 
 procedure TGeometryTest.AssertEquals(const Expected, Actual: TDoublePoint);