refactor: remove target-conditional branches (#87)

X10D.Tests/src/Collections/ByteTests.cs

@@ -47,7 +47,6 @@ internal class ByteTests
         });
     }
 
-#if NET5_0_OR_GREATER
     [Test]
     public void UnpackInternal_Fallback_ShouldUnpackToSpanCorrectly()
     {
@@ -92,7 +91,6 @@ internal class ByteTests
             Assert.That(bits[7], Is.True);
         });
     }
-#endif
 
     [Test]
     public void Unpack_ShouldRepackEqually()

X10D.Tests/src/Collections/Int16Tests.cs

@@ -1,6 +1,4 @@
-#if NET5_0_OR_GREATER
 using System.Runtime.Intrinsics.X86;
-#endif
 using NUnit.Framework;
 using X10D.Collections;
 
@@ -84,7 +82,6 @@ internal class Int16Tests
         });
     }
 
-#if NET5_0_OR_GREATER
     [Test]
     public void UnpackInternal_Ssse3_ShouldUnpackToSpanCorrectly()
     {
@@ -115,7 +112,6 @@ internal class Int16Tests
             }
         });
     }
-#endif
 
     [Test]
     public void Unpack_ShouldRepackEqually()

X10D.Tests/src/Collections/Int32Tests.cs

@@ -1,6 +1,4 @@
-#if NET5_0_OR_GREATER
 using System.Runtime.Intrinsics.X86;
-#endif
 using NUnit.Framework;
 using X10D.Collections;
 
@@ -85,7 +83,6 @@ internal class Int32Tests
         });
     }
 
-#if NET5_0_OR_GREATER
     [Test]
     public void UnpackInternal_Ssse3_ShouldUnpackToSpanCorrectly()
     {
@@ -145,7 +142,6 @@ internal class Int32Tests
             }
         });
     }
-#endif
 
     [Test]
     public void Unpack_ShouldRepackEqually()

X10D.Tests/src/Core/IntrinsicTests.cs

@@ -1,4 +1,3 @@
-#if NET6_0_OR_GREATER
 using System.Runtime.Intrinsics;
 using System.Runtime.Intrinsics.X86;
 using NUnit.Framework;
@@ -223,4 +222,3 @@ internal class IntrinsicTests
         Assert.That(result, Is.EqualTo(expectedResult));
     }
 }
-#endif

X10D.Tests/src/Core/SpanTest.cs

@@ -1,7 +1,5 @@
-#if NET5_0_OR_GREATER
 using System.Runtime.Intrinsics.Arm;
 using System.Runtime.Intrinsics.X86;
-#endif
 using NUnit.Framework;
 using X10D.Core;
 
@@ -209,7 +207,6 @@ internal class SpanTest
         Assert.That(actual, Is.EqualTo(expected));
     }
 
-#if NET5_0_OR_GREATER
     [Test]
     public void PackByteInternal_Sse2_ShouldReturnCorrectByte_GivenReadOnlySpan_Using()
     {
@@ -241,7 +238,6 @@ internal class SpanTest
 
         Assert.That(actual, Is.EqualTo(expected));
     }
-#endif
 
     [Test]
     public void PackInt16_ShouldReturnSameAsPackByte_WhenSpanHasLength8()
@@ -268,7 +264,6 @@ internal class SpanTest
         Assert.That(actual, Is.EqualTo(expected));
     }
 
-#if NET5_0_OR_GREATER
     [Test]
     public void PackInt16Internal_Sse2_ShouldReturnCorrectInt16_GivenReadOnlySpan_Using()
     {
@@ -287,7 +282,6 @@ internal class SpanTest
 
         Assert.That(actual, Is.EqualTo(expected));
     }
-#endif
 
     [Test]
     public void PackInt32Internal_Fallback_ShouldReturnCorrectInt32_GivenReadOnlySpan()
@@ -304,7 +298,6 @@ internal class SpanTest
         Assert.That(actual, Is.EqualTo(expected));
     }
 
-#if NET5_0_OR_GREATER
     [Test]
     public void PackInt32Internal_Sse2_ShouldReturnCorrectInt32_GivenReadOnlySpan()
     {
@@ -364,7 +357,6 @@ internal class SpanTest
 
         Assert.That(actual, Is.EqualTo(expected));
     }
-#endif
 
     [Test]
     public void PackInt32_ShouldReturnSameAsPackByte_WhenSpanHasLength8_UsingReadOnlySpan()

X10D.Tests/src/Drawing/ColorTests.cs

@@ -207,9 +207,7 @@ internal class ColorTests
             Assert.That(Color.Plum.GetClosestConsoleColor(), Is.EqualTo(ConsoleColor.DarkGray));
             Assert.That(Color.PowderBlue.GetClosestConsoleColor(), Is.EqualTo(ConsoleColor.DarkGray));
             Assert.That(Color.Purple.GetClosestConsoleColor(), Is.EqualTo(ConsoleColor.DarkMagenta));
-#if NET6_0_OR_GREATER
             Assert.That(Color.RebeccaPurple.GetClosestConsoleColor(), Is.EqualTo(ConsoleColor.DarkMagenta));
-#endif
             Assert.That(Color.Red.GetClosestConsoleColor(), Is.EqualTo(ConsoleColor.Red));
             Assert.That(Color.RosyBrown.GetClosestConsoleColor(), Is.EqualTo(ConsoleColor.DarkGray));
             Assert.That(Color.RoyalBlue.GetClosestConsoleColor(), Is.EqualTo(ConsoleColor.DarkCyan));

X10D.Tests/src/Text/CoreTests.cs

@@ -6,7 +6,6 @@ namespace X10D.Tests.Text;
 [TestFixture]
 internal class CoreTests
 {
-#if NET5_0_OR_GREATER
     [Test]
     public void ToJsonShouldNotBeEmpty()
     {
@@ -24,5 +23,4 @@ internal class CoreTests
         CollectionAssert.AreEqual(source, target);
         CollectionAssert.AreEquivalent(source, target);
     }
-#endif
 }

X10D.Tests/src/Text/RuneTests.cs

@@ -1,4 +1,3 @@
-#if NET5_0_OR_GREATER
 using System.Text;
 using NUnit.Framework;
 using X10D.Text;
@@ -90,4 +89,3 @@ internal class RuneTests
         Assert.That(repeated, Is.EqualTo("𐀀𐀀𐀀𐀀𐀀𐀀"));
     }
 }
-#endif

X10D.Tests/src/Text/StringTests.cs

@@ -1,7 +1,5 @@
 using System.Text;
-#if NET5_0_OR_GREATER
 using System.Text.Json.Serialization;
-#endif
 using NUnit.Framework;
 using X10D.Text;
 
@@ -418,7 +416,6 @@ internal class StringTests
         Assert.Throws<ArgumentException>(() => _ = " ".EnumParse<DayOfWeek>());
     }
 
-#if NET5_0_OR_GREATER
     [Test]
     public void FromJson_ShouldDeserializeCorrectly_GivenJsonString()
     {
@@ -434,7 +431,6 @@ internal class StringTests
             Assert.That(target.Values[2], Is.EqualTo(3));
         });
     }
-#endif
 
     [Test]
     public void GetBytes_ShouldReturnUtf8Bytes_GivenHelloWorld()
@@ -1006,11 +1002,9 @@ internal class StringTests
         });
     }
 
-#if NET5_0_OR_GREATER
     private struct SampleStructure
     {
         [JsonPropertyName("values")]
         public int[] Values { get; set; }
     }
-#endif
 }

X10D.Tests/src/Time/DateOnlyTests.cs

@@ -1,4 +1,3 @@
-#if NET6_0_OR_GREATER
 using NUnit.Framework;
 using X10D.Time;
 
@@ -230,4 +229,3 @@ internal class DateOnlyTests
         Assert.That(date.ToUnixTimeSeconds(time), Is.EqualTo(946684800));
     }
 }
-#endif

X10D.Tests/src/Time/DoubleTests.cs

@@ -1,4 +1,3 @@
-#if NET5_0_OR_GREATER
 using NUnit.Framework;
 using X10D.Time;
 
@@ -52,4 +51,3 @@ internal class DoubleTests
         Assert.That((_negativeOne).Weeks() < TimeSpan.Zero);
     }
 }
-#endif

X10D/src/Collections/ByteExtensions.cs

@@ -1,12 +1,9 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
-using X10D.CompilerServices;
-
-#if NETCOREAPP3_0_OR_GREATER
 using System.Runtime.Intrinsics;
 using System.Runtime.Intrinsics.X86;
-#endif
+using X10D.CompilerServices;
 
 namespace X10D.Collections;
 
@@ -46,13 +43,11 @@ public static class ByteExtensions
             throw new ArgumentException(ExceptionMessages.DestinationSpanLengthTooShort, nameof(destination));
         }
 
-#if NETCOREAPP3_0_OR_GREATER
         if (Sse3.IsSupported)
         {
             UnpackInternal_Ssse3(value, destination);
             return;
         }
-#endif
 
         UnpackInternal_Fallback(value, destination);
     }
@@ -66,7 +61,6 @@ public static class ByteExtensions
         }
     }
 
-#if NETCOREAPP3_0_OR_GREATER
     [MethodImpl(CompilerResources.MethodImplOptions)]
     internal unsafe static void UnpackInternal_Ssse3(this byte value, Span<bool> destination)
     {
@@ -87,5 +81,4 @@ public static class ByteExtensions
             Sse2.StoreScalar((long*)pDestination, correctness.AsInt64());
         }
     }
-#endif
 }

X10D/src/Collections/DictionaryExtensions.cs

@@ -1,7 +1,5 @@
 using System.Diagnostics.Contracts;
-#if NET6_0_OR_GREATER
 using System.Runtime.InteropServices;
-#endif
 using System.Web;
 
 namespace X10D.Collections;
@@ -47,23 +45,10 @@ public static class DictionaryExtensions
             throw new ArgumentNullException(nameof(updateValueFactory));
         }
 
-#if NET6_0_OR_GREATER
         ref var value = ref CollectionsMarshal.GetValueRefOrAddDefault(dictionary, key, out bool exists);
         // DO NOT CHANGE. reassigning value is necessary to mutate the dictionary, due to ref return above.
         // mutation of the dictionary is INTENDED BEHAVIOUR. this is not a mistake.
         return value = exists ? updateValueFactory(key, value!) : addValue;
-#else
-        if (dictionary.TryGetValue(key, out TValue? old))
-        {
-            TValue updated = updateValueFactory(key, old);
-            dictionary[key] = updated;
-
-            return updated;
-        }
-
-        dictionary.Add(key, addValue);
-        return addValue;
-#endif
     }
 
     /// <summary>
@@ -157,25 +142,10 @@ public static class DictionaryExtensions
             throw new ArgumentNullException(nameof(updateValueFactory));
         }
 
-#if NET6_0_OR_GREATER
         ref TValue? value = ref CollectionsMarshal.GetValueRefOrAddDefault(dictionary, key, out bool exists);
         // DO NOT CHANGE. reassigning value is necessary to mutate the dictionary, due to ref return above.
         // mutation of the dictionary is INTENDED BEHAVIOUR. this is not a mistake.
         return value = exists ? updateValueFactory(key, value!) : addValueFactory(key);
-#else
-        if (dictionary.TryGetValue(key, out TValue? old))
-        {
-            TValue updated = updateValueFactory(key, old);
-            dictionary[key] = updated;
-
-            return updated;
-        }
-
-        TValue add = addValueFactory(key);
-        dictionary.Add(key, add);
-
-        return add;
-#endif
     }
 
     /// <summary>
@@ -284,25 +254,10 @@ public static class DictionaryExtensions
             throw new ArgumentNullException(nameof(updateValueFactory));
         }
 
-#if NET6_0_OR_GREATER
         ref TValue? value = ref CollectionsMarshal.GetValueRefOrAddDefault(dictionary, key, out bool exists);
         // DO NOT CHANGE. reassigning value is necessary to mutate the dictionary, due to ref return above.
         // mutation of the dictionary is INTENDED BEHAVIOUR. this is not a mistake.
         return value = exists ? updateValueFactory(key, value!, factoryArgument) : addValueFactory(key, factoryArgument);
-#else
-        if (dictionary.TryGetValue(key, out TValue? old))
-        {
-            TValue updated = updateValueFactory(key, old, factoryArgument);
-            dictionary[key] = updated;
-
-            return updated;
-        }
-
-        TValue add = addValueFactory(key, factoryArgument);
-        dictionary.Add(key, add);
-
-        return add;
-#endif
     }
 
     /// <summary>

X10D/src/Collections/Int16Extensions.cs

@@ -1,12 +1,9 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
-using X10D.CompilerServices;
-
-#if NETCOREAPP3_0_OR_GREATER
 using System.Runtime.Intrinsics;
 using System.Runtime.Intrinsics.X86;
-#endif
+using X10D.CompilerServices;
 
 namespace X10D.Collections;
 
@@ -46,13 +43,11 @@ public static class Int16Extensions
             throw new ArgumentException(ExceptionMessages.DestinationSpanLengthTooShort, nameof(destination));
         }
 
-#if NETCOREAPP3_0_OR_GREATER
         if (Sse3.IsSupported)
         {
             UnpackInternal_Ssse3(value, destination);
             return;
         }
-#endif
 
         UnpackInternal_Fallback(value, destination);
     }
@@ -66,7 +61,6 @@ public static class Int16Extensions
         }
     }
 
-#if NETCOREAPP3_0_OR_GREATER
     [MethodImpl(CompilerResources.MethodImplOptions)]
     internal unsafe static void UnpackInternal_Ssse3(this short value, Span<bool> destination)
     {
@@ -89,5 +83,4 @@ public static class Int16Extensions
             Sse2.Store((byte*)pDestination, correctness);
         }
     }
-#endif
 }

X10D/src/Collections/Int32Extensions.cs

@@ -1,12 +1,9 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
-using X10D.CompilerServices;
-
-#if NETCOREAPP3_0_OR_GREATER
 using System.Runtime.Intrinsics;
 using System.Runtime.Intrinsics.X86;
-#endif
+using X10D.CompilerServices;
 
 namespace X10D.Collections;
 
@@ -46,7 +43,6 @@ public static class Int32Extensions
             throw new ArgumentException(ExceptionMessages.DestinationSpanLengthTooShort, nameof(destination));
         }
 
-#if NETCOREAPP3_0_OR_GREATER
         if (Avx2.IsSupported)
         {
             UnpackInternal_Avx2(value, destination);
@@ -58,7 +54,6 @@ public static class Int32Extensions
             UnpackInternal_Ssse3(value, destination);
             return;
         }
-#endif
 
         UnpackInternal_Fallback(value, destination);
     }
@@ -72,7 +67,6 @@ public static class Int32Extensions
         }
     }
 
-#if NETCOREAPP3_0_OR_GREATER
     [MethodImpl(CompilerResources.MethodImplOptions)]
     internal static unsafe void UnpackInternal_Ssse3(this int value, Span<bool> destination)
     {
@@ -130,5 +124,4 @@ public static class Int32Extensions
             Avx.Store((byte*)pDestination, correctness);
         }
     }
-#endif
 }

X10D/src/CompilerServices/CompilerResources.cs

@@ -4,10 +4,6 @@ namespace X10D.CompilerServices;
 
 internal static class CompilerResources
 {
-#if NETCOREAPP3_0_OR_GREATER
     public const MethodImplOptions MethodImplOptions = System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining |
                                                        System.Runtime.CompilerServices.MethodImplOptions.AggressiveOptimization;
-#else
-    public const MethodImplOptions MethodImplOptions = System.Runtime.CompilerServices.MethodImplOptions.AggressiveInlining;
-#endif
 }

X10D/src/Core/EnumExtensions.cs

@@ -20,11 +20,7 @@ public static class EnumExtensions
     public static T Next<T>(this T value)
         where T : struct, Enum
     {
-#if NET5_0_OR_GREATER
         T[] values = Enum.GetValues<T>();
-#else
-        T[] values = Enum.GetValues(typeof(T)).Cast<T>().ToArray();
-#endif
         int index = Array.IndexOf(values, value) + 1;
         index %= values.Length;
         return values[index];
@@ -44,11 +40,7 @@ public static class EnumExtensions
     public static T NextUnchecked<T>(this T value)
         where T : struct, Enum
     {
-#if NET5_0_OR_GREATER
         T[] values = Enum.GetValues<T>();
-#else
-        T[] values = Enum.GetValues(typeof(T)).Cast<T>().ToArray();
-#endif
         int index = Array.IndexOf(values, value) + 1;
         return values[index];
     }
@@ -66,11 +58,7 @@ public static class EnumExtensions
     public static T Previous<T>(this T value)
         where T : struct, Enum
     {
-#if NET5_0_OR_GREATER
         T[] values = Enum.GetValues<T>();
-#else
-        T[] values = Enum.GetValues(typeof(T)).Cast<T>().ToArray();
-#endif
         int index = Array.IndexOf(values, value) - 1;
         int length = values.Length;
 
@@ -94,11 +82,7 @@ public static class EnumExtensions
     public static T PreviousUnchecked<T>(this T value)
         where T : struct, Enum
     {
-#if NET5_0_OR_GREATER
         T[] values = Enum.GetValues<T>();
-#else
-        T[] values = Enum.GetValues(typeof(T)).Cast<T>().ToArray();
-#endif
         int index = Array.IndexOf(values, value) - 1;
         return values[index];
     }

X10D/src/Core/IntrinsicExtensions.cs

@@ -1,4 +1,3 @@
-#if NETCOREAPP3_0_OR_GREATER
 using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
@@ -188,4 +187,3 @@ public static class IntrinsicExtensions
         return Sse2.Shuffle(vector.AsDouble(), vector.AsDouble(), 0b01).AsUInt64();
     }
 }
-#endif

X10D/src/Core/IntrinsicUtility.cs

@@ -1,5 +1,3 @@
-#if NETCOREAPP3_0_OR_GREATER
-
 using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
@@ -184,34 +182,22 @@ public static class IntrinsicUtility
     [MethodImpl(CompilerResources.MethodImplOptions)]
     internal static Vector64<T> GetUninitializedVector64<T>() where T : struct
     {
-#if NET6_0_OR_GREATER
         Unsafe.SkipInit(out Vector64<T> output);
         return output;
-#else
-        return default;
-#endif
     }
 
     [MethodImpl(CompilerResources.MethodImplOptions)]
     internal static Vector128<T> GetUninitializedVector128<T>() where T : struct
     {
-#if NET6_0_OR_GREATER
         Unsafe.SkipInit(out Vector128<T> output);
         return output;
-#else
-        return default;
-#endif
     }
 
     [MethodImpl(CompilerResources.MethodImplOptions)]
     internal static Vector256<T> GetUninitializedVector256<T>() where T : struct
     {
-#if NET6_0_OR_GREATER
         Unsafe.SkipInit(out Vector256<T> output);
         return output;
-#else
-        return default;
-#endif
     }
 
     [Pure]
@@ -315,5 +301,3 @@ public static class IntrinsicUtility
         return Avx2.Add(high, ac);
     }
 }
-
-#endif

X10D/src/Core/RandomExtensions.cs

@@ -11,10 +11,6 @@ namespace X10D.Core;
 /// </summary>
 public static class RandomExtensions
 {
-#if !NET6_0_OR_GREATER
-    private static readonly Random Shared = new();
-#endif
-
     /// <summary>
     ///     Returns a random value that defined in a specified enum.
     /// </summary>
@@ -505,10 +501,6 @@ public static class RandomExtensions
 
     internal static Random GetShared()
     {
-#if NET6_0_OR_GREATER
         return Random.Shared;
-#else
-        return Shared;
-#endif
     }
 }

X10D/src/Core/SpanExtensions.cs

@@ -2,13 +2,10 @@ using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
-using X10D.CompilerServices;
-
-#if NETCOREAPP3_0_OR_GREATER
 using System.Runtime.Intrinsics;
 using System.Runtime.Intrinsics.X86;
 using System.Runtime.Intrinsics.Arm;
-#endif
+using X10D.CompilerServices;
 
 #if NET7_0_OR_GREATER
 using System.Diagnostics;
@@ -21,7 +18,6 @@ namespace X10D.Core;
 /// </summary>
 public static class SpanExtensions
 {
-#if NETCOREAPP3_0_OR_GREATER
     private const ulong IntegerPackingMagic = 0x0102040810204080;
 
     [ExcludeFromCodeCoverage]
@@ -35,7 +31,6 @@ public static class SpanExtensions
     {
         get => Vector256.Create(IntegerPackingMagic);
     }
-#endif
 
     /// <summary>
     ///     Returns a value indicating whether a specific enumeration value is contained with the current span of elements.
@@ -71,7 +66,6 @@ public static class SpanExtensions
     [MethodImpl(CompilerResources.MethodImplOptions)]
     public static bool Contains<T>(this ReadOnlySpan<T> span, T value) where T : struct, Enum
     {
-#if NET6_0_OR_GREATER
         unsafe
         {
 #pragma warning disable CS8500
@@ -114,17 +108,6 @@ public static class SpanExtensions
                 // dotcover enable
             }
         }
-#else
-        foreach (var it in span)
-        {
-            if (EqualityComparer<T>.Default.Equals(it, value))
-            {
-                return true;
-            }
-        }
-
-        return false;
-#endif
     }
 
     /// <summary>
@@ -161,7 +144,6 @@ public static class SpanExtensions
             return PackByteInternal_Fallback(source);
         }
 
-#if NETCOREAPP3_0_OR_GREATER
         if (!BitConverter.IsLittleEndian)
         {
             return PackByteInternal_Fallback(source);
@@ -176,7 +158,6 @@ public static class SpanExtensions
         {
             return PackByteInternal_AdvSimd(source);
         }
-#endif
 
         return PackByteInternal_Fallback(source);
     }
@@ -217,12 +198,10 @@ public static class SpanExtensions
                     goto default;
                 }
 
-#if NETCOREAPP3_0_OR_GREATER
                 if (Sse2.IsSupported)
                 {
                     return PackInt16Internal_Sse2(source);
                 }
-#endif
 
                 goto default;
             case < 16:
@@ -269,7 +248,6 @@ public static class SpanExtensions
                 return PackInt16(source);
 
             case 32:
-#if NETCOREAPP3_0_OR_GREATER
                 if (!BitConverter.IsLittleEndian)
                 {
                     goto default;
@@ -289,7 +267,6 @@ public static class SpanExtensions
                 {
                     return PackInt32Internal_AdvSimd(source);
                 }
-#endif
                 goto default;
 
             default:
@@ -383,7 +360,6 @@ public static class SpanExtensions
         return result;
     }
 
-#if NETCOREAPP3_0_OR_GREATER
     [Pure]
     [MethodImpl(CompilerResources.MethodImplOptions)]
     internal static byte PackByteInternal_Sse2(this ReadOnlySpan<bool> source)
@@ -499,7 +475,6 @@ public static class SpanExtensions
         }
     }
 
-#if NET5_0_OR_GREATER
     // dotcover disable
     //NOSONAR
     [Pure]
@@ -517,6 +492,4 @@ public static class SpanExtensions
     }
     //NOSONAR
     // dotcover enable
-#endif
-#endif
 }

X10D/src/Drawing/ColorExtensions.cs

@@ -72,17 +72,9 @@ public static class ColorExtensions
         double blue = color.B;
         var delta = double.MaxValue;
 
-#if NET5_0_OR_GREATER
         foreach (ConsoleColor consoleColor in Enum.GetValues<ConsoleColor>())
-#else
-        foreach (ConsoleColor consoleColor in Enum.GetValues(typeof(ConsoleColor)))
-#endif
         {
-#if NET5_0_OR_GREATER
             string name = Enum.GetName(consoleColor)!;
-#else
-            string name = Enum.GetName(typeof(ConsoleColor), consoleColor)!;
-#endif
             Color currentColor = Color.FromName(name == "DarkYellow" ? "Orange" : name); // bug fix
             double r = currentColor.R - red;
             double g = currentColor.G - green;

X10D/src/IO/DecimalExtensions.cs

@@ -93,13 +93,7 @@ public static class DecimalExtensions
 
     private static void GetBits(decimal value, Span<int> destination)
     {
-#if NET5_0_OR_GREATER
         _ = decimal.GetBits(value, destination);
-#else
-        Span<byte> buffer = stackalloc byte[16];
-        MemoryMarshal.Write(buffer, ref value);
-        WriteBits(destination, buffer);
-#endif
     }
 
 #if !NET5_0_OR_GREATER

X10D/src/IO/DoubleExtensions.cs

@@ -43,17 +43,7 @@ public static class DoubleExtensions
     /// <returns><see langword="true" /> if the conversion was successful; otherwise, <see langword="false" />.</returns>
     public static bool TryWriteBigEndianBytes(this double value, Span<byte> destination)
     {
-#if NET5_0_OR_GREATER
         return BinaryPrimitives.TryWriteDoubleBigEndian(destination, value);
-#else
-        if (BitConverter.IsLittleEndian)
-        {
-            long tmp = BinaryPrimitives.ReverseEndianness(BitConverter.DoubleToInt64Bits(value));
-            return MemoryMarshal.TryWrite(destination, ref tmp);
-        }
-
-        return MemoryMarshal.TryWrite(destination, ref value);
-#endif
     }
 
     /// <summary>
@@ -64,16 +54,6 @@ public static class DoubleExtensions
     /// <returns><see langword="true" /> if the conversion was successful; otherwise, <see langword="false" />.</returns>
     public static bool TryWriteLittleEndianBytes(this double value, Span<byte> destination)
     {
-#if NET5_0_OR_GREATER
         return BinaryPrimitives.TryWriteDoubleLittleEndian(destination, value);
-#else
-        if (BitConverter.IsLittleEndian)
-        {
-            return MemoryMarshal.TryWrite(destination, ref value);
-        }
-
-        long tmp = BinaryPrimitives.ReverseEndianness(BitConverter.DoubleToInt64Bits(value));
-        return MemoryMarshal.TryWrite(destination, ref tmp);
-#endif
     }
 }

X10D/src/IO/SingleExtensions.cs

@@ -45,17 +45,7 @@ public static class SingleExtensions
     /// <returns><see langword="true" /> if the conversion was successful; otherwise, <see langword="false" />.</returns>
     public static bool TryWriteBigEndianBytes(this float value, Span<byte> destination)
     {
-#if NET5_0_OR_GREATER
         return BinaryPrimitives.TryWriteSingleBigEndian(destination, value);
-#else
-        if (BitConverter.IsLittleEndian)
-        {
-            int tmp = BinaryPrimitives.ReverseEndianness(BitConverter.SingleToInt32Bits(value));
-            return MemoryMarshal.TryWrite(destination, ref tmp);
-        }
-
-        return MemoryMarshal.TryWrite(destination, ref value);
-#endif
     }
 
     /// <summary>
@@ -66,16 +56,6 @@ public static class SingleExtensions
     /// <returns><see langword="true" /> if the conversion was successful; otherwise, <see langword="false" />.</returns>
     public static bool TryWriteLittleEndianBytes(this float value, Span<byte> destination)
     {
-#if NET5_0_OR_GREATER
         return BinaryPrimitives.TryWriteSingleLittleEndian(destination, value);
-#else
-        if (BitConverter.IsLittleEndian)
-        {
-            return MemoryMarshal.TryWrite(destination, ref value);
-        }
-
-        int tmp = BinaryPrimitives.ReverseEndianness(BitConverter.SingleToInt32Bits(value));
-        return MemoryMarshal.TryWrite(destination, ref tmp);
-#endif
     }
 }

X10D/src/IO/StreamExtensions.Reading.cs

@@ -1,5 +1,4 @@
 using System.Buffers.Binary;
-using System.Runtime.InteropServices;
 
 namespace X10D.IO;
 
@@ -40,11 +39,7 @@ public static partial class StreamExtensions
             buffer.Reverse();
         }
 
-#if NET5_0_OR_GREATER
         return new decimal(buffer);
-#else
-        return new decimal(buffer.ToArray());
-#endif
     }
 
     /// <summary>
@@ -82,11 +77,7 @@ public static partial class StreamExtensions
             buffer.Reverse();
         }
 
-#if NET5_0_OR_GREATER
         return new decimal(buffer);
-#else
-        return new decimal(buffer.ToArray());
-#endif
     }
 
     /// <summary>
@@ -110,16 +101,7 @@ public static partial class StreamExtensions
 
         Span<byte> buffer = stackalloc byte[8];
         _ = stream.Read(buffer);
-#if NET5_0_OR_GREATER
         return BinaryPrimitives.ReadDoubleBigEndian(buffer);
-#else
-        if (BitConverter.IsLittleEndian)
-        {
-            buffer.Reverse();
-        }
-
-        return MemoryMarshal.Read<double>(buffer);
-#endif
     }
 
     /// <summary>
@@ -144,16 +126,7 @@ public static partial class StreamExtensions
 
         Span<byte> buffer = stackalloc byte[8];
         _ = stream.Read(buffer);
-#if NET5_0_OR_GREATER
         return BinaryPrimitives.ReadDoubleLittleEndian(buffer);
-#else
-        if (!BitConverter.IsLittleEndian)
-        {
-            buffer.Reverse();
-        }
-
-        return MemoryMarshal.Read<double>(buffer);
-#endif
     }
 
     /// <summary>
@@ -323,16 +296,7 @@ public static partial class StreamExtensions
 
         Span<byte> buffer = stackalloc byte[4];
         _ = stream.Read(buffer);
-#if NET5_0_OR_GREATER
         return BinaryPrimitives.ReadSingleBigEndian(buffer);
-#else
-        if (BitConverter.IsLittleEndian)
-        {
-            buffer.Reverse();
-        }
-
-        return MemoryMarshal.Read<float>(buffer);
-#endif
     }
 
     /// <summary>
@@ -358,16 +322,7 @@ public static partial class StreamExtensions
 
         Span<byte> buffer = stackalloc byte[4];
         _ = stream.Read(buffer);
-#if NET5_0_OR_GREATER
         return BinaryPrimitives.ReadSingleLittleEndian(buffer);
-#else
-        if (!BitConverter.IsLittleEndian)
-        {
-            buffer.Reverse();
-        }
-
-        return MemoryMarshal.Read<float>(buffer);
-#endif
     }
 
     /// <summary>

X10D/src/Linq/EnumerableExtensions.cs

@@ -1,6 +1,4 @@
-#if NET5_0_OR_GREATER
 using System.Runtime.InteropServices;
-#endif
 
 namespace X10D.Linq;
 
@@ -389,11 +387,9 @@ public static class EnumerableExtensions
                 span = array;
                 break;
 
-#if NET5_0_OR_GREATER
             case List<TSource> list:
                 span = CollectionsMarshal.AsSpan(list);
                 break;
-#endif
 
             default:
                 span = default;

X10D/src/Math/MathUtility.cs

@@ -253,15 +253,7 @@ public static class MathUtility
     public static float Pulse(float value, float lowerBound, float upperBound)
     {
         bool result = lowerBound <= value && value <= upperBound;
-#if NET6_0_OR_GREATER
         return Unsafe.As<bool, int>(ref result);
-#else
-        unsafe
-        {
-            var pResult = (int*)&result;
-            return *pResult;
-        }
-#endif
     }
 
     /// <summary>
@@ -277,15 +269,7 @@ public static class MathUtility
     public static double Pulse(double value, double lowerBound, double upperBound)
     {
         bool result = lowerBound <= value && value <= upperBound;
-#if NET6_0_OR_GREATER
         return Unsafe.As<bool, int>(ref result);
-#else
-        unsafe
-        {
-            var pResult = (int*)&result;
-            return *pResult;
-        }
-#endif
     }
 
     /// <summary>

X10D/src/Numerics/UInt32Extensions.cs

@@ -24,20 +24,7 @@ public static class UInt32Extensions
     [MethodImpl(CompilerResources.MethodImplOptions)]
     public static int PopCount(this uint value)
     {
-#if NETCOREAPP3_1_OR_GREATER
         return BitOperations.PopCount(value);
-#else
-        const uint c1 = 0x_55555555u;
-        const uint c2 = 0x_33333333u;
-        const uint c3 = 0x_0F0F0F0Fu;
-        const uint c4 = 0x_01010101u;
-
-        value -= (value >> 1) & c1;
-        value = (value & c2) + ((value >> 2) & c2);
-        value = (((value + (value >> 4)) & c3) * c4) >> 24;
-
-        return (int)value;
-#endif
     }
 
     /// <summary>
@@ -82,17 +69,6 @@ public static class UInt32Extensions
     [MethodImpl(CompilerResources.MethodImplOptions)]
     public static uint RoundUpToPowerOf2(this uint value)
     {
-#if NET6_0_OR_GREATER
         return BitOperations.RoundUpToPowerOf2(value);
-#else
-        // Based on https://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
-        --value;
-        value |= value >> 1;
-        value |= value >> 2;
-        value |= value >> 4;
-        value |= value >> 8;
-        value |= value >> 16;
-        return value + 1;
-#endif
     }
 }

X10D/src/Numerics/UInt64Extensions.cs

@@ -24,20 +24,7 @@ public static class UInt64Extensions
     [MethodImpl(CompilerResources.MethodImplOptions)]
     public static int PopCount(this ulong value)
     {
-#if NETCOREAPP3_1_OR_GREATER
         return BitOperations.PopCount(value);
-#else
-        const ulong c1 = 0x_55555555_55555555ul;
-        const ulong c2 = 0x_33333333_33333333ul;
-        const ulong c3 = 0x_0F0F0F0F_0F0F0F0Ful;
-        const ulong c4 = 0x_01010101_01010101ul;
-
-        value -= (value >> 1) & c1;
-        value = (value & c2) + ((value >> 2) & c2);
-        value = (((value + (value >> 4)) & c3) * c4) >> 56;
-
-        return (int)value;
-#endif
     }
 
     /// <summary>
@@ -82,18 +69,6 @@ public static class UInt64Extensions
     [MethodImpl(CompilerResources.MethodImplOptions)]
     public static ulong RoundUpToPowerOf2(this ulong value)
     {
-#if NET6_0_OR_GREATER
         return BitOperations.RoundUpToPowerOf2(value);
-#else
-        // Based on https://graphics.stanford.edu/~seander/bithacks.html#RoundUpPowerOf2
-        --value;
-        value |= value >> 1;
-        value |= value >> 2;
-        value |= value >> 4;
-        value |= value >> 8;
-        value |= value >> 16;
-        value |= value >> 32;
-        return value + 1;
-#endif
     }
 }

X10D/src/Text/EnumerableExtensions.cs

@@ -55,12 +55,10 @@ public static class EnumerableExtensions
             throw new ArgumentNullException(nameof(pattern));
         }
 
-#if NET6_0_OR_GREATER
         if (source.TryGetNonEnumeratedCount(out int count) && count == 0)
         {
             yield break;
         }
-#endif
 
         var options = RegexOptions.Compiled | (ignoreCase ? RegexOptions.IgnoreCase : RegexOptions.None);
         var regex = new Regex(pattern, options, Regex.InfiniteMatchTimeout);

X10D/src/Text/Extensions.cs

@@ -1,4 +1,3 @@
-#if NET5_0_OR_GREATER
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
 using System.Text.Json;
@@ -25,4 +24,3 @@ public static class Extensions
         return JsonSerializer.Serialize(value, options);
     }
 }
-#endif

X10D/src/Text/RuneExtensions.cs

@@ -1,4 +1,3 @@
-#if NETCOREAPP3_0_OR_GREATER
 using System.Diagnostics;
 using System.Diagnostics.Contracts;
 using System.Globalization;
@@ -113,4 +112,3 @@ public static class RuneExtensions
         }
     }
 }
-#endif

X10D/src/Text/StringExtensions.cs

@@ -2,9 +2,7 @@ using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
 using System.Text;
-#if NET5_0_OR_GREATER
 using System.Text.Json;
-#endif
 using X10D.Collections;
 using X10D.CompilerServices;
 using X10D.Core;
@@ -575,7 +573,6 @@ public static class StringExtensions
         return Enum.Parse<T>(value, ignoreCase);
     }
 
-#if NET5_0_OR_GREATER
     /// <summary>
     ///     Returns an object from the specified JSON string.
     /// </summary>
@@ -590,7 +587,6 @@ public static class StringExtensions
     {
         return JsonSerializer.Deserialize<T>(value, options);
     }
-#endif
 
     /// <summary>
     ///     Gets a <see cref="byte" />[] representing the value the <see cref="string" /> with
@@ -688,7 +684,6 @@ public static class StringExtensions
 
         for (var index = 0; index < value.Length; index++)
         {
-#if NETCOREAPP3_0_OR_GREATER
             var rune = new Rune(value[index]);
 
             if (!Rune.IsLetter(rune))
@@ -700,19 +695,6 @@ public static class StringExtensions
             {
                 return false;
             }
-#else
-            char current = value[index];
-
-            if (!char.IsLetter(current))
-            {
-                continue;
-            }
-
-            if (!char.IsLower(current))
-            {
-                return false;
-            }
-#endif
         }
 
         return true;
@@ -777,7 +759,6 @@ public static class StringExtensions
 
         for (int index = 0, endIndex = value.Length - 1; index < value.Length; index++, endIndex--)
         {
-#if NETCOREAPP3_0_OR_GREATER
             Rune startRune = new Rune(value[index]);
             Rune endRune = new Rune(value[endIndex]);
 
@@ -797,27 +778,6 @@ public static class StringExtensions
             {
                 return false;
             }
-#else
-            char startChar = value[index];
-            char endChar = value[endIndex];
-
-            if (!char.IsLetter(startChar) && !char.IsNumber(startChar))
-            {
-                endIndex++;
-                continue;
-            }
-
-            if (!char.IsLetter(endChar) && !char.IsNumber(endChar))
-            {
-                index--;
-                continue;
-            }
-
-            if (char.ToUpperInvariant(startChar) != char.ToUpperInvariant(endChar))
-            {
-                return false;
-            }
-#endif
         }
 
         return true;
@@ -841,7 +801,6 @@ public static class StringExtensions
 
         for (var index = 0; index < value.Length; index++)
         {
-#if NETCOREAPP3_0_OR_GREATER
             var rune = new Rune(value[index]);
 
             if (!Rune.IsLetter(rune))
@@ -853,19 +812,6 @@ public static class StringExtensions
             {
                 return false;
             }
-#else
-            char current = value[index];
-
-            if (!char.IsLetter(current))
-            {
-                continue;
-            }
-
-            if (!char.IsUpper(current))
-            {
-                return false;
-            }
-#endif
         }
 
         return true;

X10D/src/Time/DateOnlyExtensions.cs

@@ -1,4 +1,3 @@
-#if NET6_0_OR_GREATER
 using System.Diagnostics.CodeAnalysis;
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
@@ -198,4 +197,3 @@ public static class DateOnlyExtensions
         return value.ToDateTime(time).ToUnixTimeSeconds();
     }
 }
-#endif

X10D/src/Time/HalfExtensions.cs

@@ -1,4 +1,3 @@
-#if NET5_0_OR_GREATER
 using System.Diagnostics.Contracts;
 using System.Runtime.CompilerServices;
 using X10D.CompilerServices;
@@ -92,4 +91,3 @@ public static class HalfExtensions
         return TimeSpan.FromDays((float)value * 7);
     }
 }
-#endif