Add polyfill for Math.Log2(double)

PolyShim.Tests/NetCore30/MathTests.cs

@@ -0,0 +1,20 @@
+using System;
+using FluentAssertions;
+using Xunit;
+
+namespace PolyShim.Tests.NetCore30;
+
+public class MathTests
+{
+    [Fact]
+    public void Log2_Test()
+    {
+        // Act & assert
+        Math.Log2(8.0).Should().BeApproximately(3.0, 1e-12);
+        Math.Log2(1.0).Should().Be(0.0);
+        Math.Log2(0.0).Should().Be(double.NegativeInfinity);
+        Math.Log2(double.PositiveInfinity).Should().Be(double.PositiveInfinity);
+        Math.Log2(-1.0).Should().Be(double.NaN);
+        Math.Log2(double.NaN).Should().Be(double.NaN);
+    }
+}

PolyShim/NetCore30/Math.cs

@@ -0,0 +1,19 @@
+#if (NETCOREAPP && !NETCOREAPP3_0_OR_GREATER) || (NETFRAMEWORK) || (NETSTANDARD)
+#nullable enable
+#pragma warning disable CS0436
+
+using System;
+using System.Diagnostics.CodeAnalysis;
+
+#if !POLYSHIM_INCLUDE_COVERAGE
+[ExcludeFromCodeCoverage]
+#endif
+internal static class MemberPolyfills_NetCore30_Math
+{
+    extension(Math)
+    {
+        // https://learn.microsoft.com/dotnet/api/system.math.log2
+        public static double Log2(double x) => Math.Log(x, 2);
+    }
+}
+#endif

Signatures.md

@@ -1,8 +1,8 @@
 # Signatures
 
-- **Total:** 620
+- **Total:** 621
 - **Types:** 114
-- **Members:** 506
+- **Members:** 507
 
 ___
 
@@ -396,6 +396,7 @@ ___
   - [`IEnumerator<Match> GetEnumerator()`](https://learn.microsoft.com/dotnet/api/system.text.regularexpressions.matchcollection.system-collections-generic-ienumerable-system-text-regularexpressions-match--getenumerator) <sup><sub>.NET Core 2.0</sub></sup>
   - [`Match[] ToArray()`](https://learn.microsoft.com/dotnet/api/system.text.regularexpressions.matchcollection.system-collections-generic-ienumerable-system-text-regularexpressions-match--getenumerator) <sup><sub>.NET Core 2.0</sub></sup>
 - `Math`
+  - [`static double Log2(double)`](https://learn.microsoft.com/dotnet/api/system.math.log2) <sup><sub>.NET Core 3.0</sub></sup>
   - [`static IntPtr Clamp(IntPtr, IntPtr, IntPtr)`](https://learn.microsoft.com/dotnet/api/system.math.clamp#system-math-clamp(system-intptr-system-intptr-system-intptr)) <sup><sub>.NET 6.0</sub></sup>
   - [`static T Clamp<T>(T, T, T) where T : IComparable<T>`](https://learn.microsoft.com/dotnet/api/system.math.clamp) <sup><sub>.NET Core 2.0</sub></sup>
 - `MaybeNullAttribute`