TolerantMath: implemented Floor and Ceiling

src/ImageSharp/Common/Helpers/TolerantMath.cs

@@ -1,12 +1,14 @@
 // Copyright (c) Six Labors and contributors.
 // Licensed under the Apache License, Version 2.0.
 
+using System;
 using System.Runtime.CompilerServices;
 
 namespace SixLabors.ImageSharp
 {
     /// <summary>
-    /// Implements math operations using tolerant comparison.
+    /// Implements basic math operations using tolerant comparison
+    /// whenever an equality check is needed.
     /// </summary>
     internal struct TolerantMath
     {
@@ -71,5 +73,29 @@ namespace SixLabors.ImageSharp
         /// </summary>
         [MethodImpl(InliningOptions.ShortMethod)]
         public bool IsLessOrEqual(double a, double b) => b >= a - this.epsilon;
+
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public double Ceiling(double a)
+        {
+            double rem = Math.IEEERemainder(a, 1);
+            if (this.IsZero(rem))
+            {
+                return Math.Round(a);
+            }
+
+            return Math.Ceiling(a);
+        }
+
+        [MethodImpl(InliningOptions.ShortMethod)]
+        public double Floor(double a)
+        {
+            double rem = Math.IEEERemainder(a, 1);
+            if (this.IsZero(rem))
+            {
+                return Math.Round(a);
+            }
+
+            return Math.Floor(a);
+        }
     }
 }

tests/ImageSharp.Tests/Helpers/TolerantMathTests.cs

@@ -126,5 +126,43 @@ namespace SixLabors.ImageSharp.Tests.Helpers
             Assert.False(this.tolerantMath.IsGreaterOrEqual(a, b));
             Assert.False(this.tolerantMath.IsLessOrEqual(b, a));
         }
+
+        [Theory]
+        [InlineData(3.5, 4.0)]
+        [InlineData(3.89, 4.0)]
+        [InlineData(4.09, 4.0)]
+        [InlineData(4.11, 5.0)]
+        [InlineData(0.11, 1)]
+        [InlineData(0.05, 0)]
+        [InlineData(-0.5, 0)]
+        [InlineData(-0.95, -1)]
+        [InlineData(-1.05, -1)]
+        [InlineData(-1.5, -1)]
+        public void Ceiling(double value, double expected)
+        {
+            double actual = this.tolerantMath.Ceiling(value);
+            Assert.Equal(expected, actual);
+        }
+
+        [Theory]
+        [InlineData(1, 1)]
+        [InlineData(0.99, 1)]
+        [InlineData(0.5, 0)]
+        [InlineData(0.01, 0)]
+        [InlineData(-0.09, 0)]
+        [InlineData(-0.11, -1)]
+        [InlineData(-100.11, -101)]
+        [InlineData(-100.09, -100)]
+        public void Floor(double value, double expected)
+        {
+            double plz1 = Math.IEEERemainder(1.1, 1);
+            double plz2 = Math.IEEERemainder(0.9, 1);
+
+            double plz3 = Math.IEEERemainder(-1.1, 1);
+            double plz4 = Math.IEEERemainder(-0.9, 1);
+
+            double actual = this.tolerantMath.Floor(value);
+            Assert.Equal(expected, actual);
+        }
     }
 }

tests/ImageSharp.Tests/ImageSharp.Tests.csproj

@@ -1,6 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
   <PropertyGroup>
-    <TargetFrameworks>net462;net472;netcoreapp2.1</TargetFrameworks>
+    <!--<TargetFrameworks>net462;net472;netcoreapp2.1</TargetFrameworks>-->
+    <TargetFramework>netcoreapp2.1</TargetFramework>
     <AllowUnsafeBlocks>True</AllowUnsafeBlocks>
     <LangVersion>latest</LangVersion>
     <DebugType Condition="$(codecov) != ''">full</DebugType>