Add implicit conversions between Ulid and string, small performance optimizations, update README and tests accordingly.

README.md

@@ -204,7 +204,7 @@ Converts the ULID to a canonical string representation. Format arguments are ign
 `==`, `!=`, `<`, `<=`, `>`, `>=`.
 - Implements standard comparison and equality methods:\
 `CompareTo`, `Equals`, `GetHashCode`.
-- Provides implicit operators to and from `Guid`.
+- Provides implicit operators to and from `Guid` and `string`.
 
 ### GenerationOptions
 
@@ -448,11 +448,11 @@ Job=DefaultJob
 | ToGuid          | Ulid               |   0.7462 ns | 0.0117 ns |      - |         - |
 | ToGuid          | NUlid              |   0.2691 ns | 0.0070 ns |      - |         - |
 
-| ToString        | ByteAetherUlid     |  12.2227 ns | 0.2543 ns | 0.0096 |      80 B |
-| ToString        | NetUlid            |  23.7706 ns | 0.2422 ns | 0.0095 |      80 B |
-| ToString        | Ulid               |  11.1126 ns | 0.2121 ns | 0.0096 |      80 B |
-| ToString        | NUlid              |  28.9672 ns | 0.1506 ns | 0.0095 |      80 B |
-| ToString        | Guid               |   7.2446 ns | 0.0341 ns | 0.0115 |      96 B |
+| ToString        | ByteAetherUlid     |   12.254 ns | 0.2822 ns | 0.0096 |      80 B |
+| ToString        | NetUlid            |   26.314 ns | 0.2748 ns | 0.0095 |      80 B |
+| ToString        | Ulid               |   12.373 ns | 0.1887 ns | 0.0096 |      80 B |
+| ToString        | NUlid              |   27.661 ns | 0.2090 ns | 0.0095 |      80 B |
+| ToString        | Guid               |    7.208 ns | 0.0447 ns | 0.0115 |      96 B |
 
 | CompareTo       | ByteAetherUlid     |   0.0007 ns | 0.0022 ns |      - |         - |
 | CompareTo       | NetUlid            |   3.6812 ns | 0.0298 ns |      - |         - |

src/ByteAether.Ulid.Tests/Ulid.Comparable.Tests.cs

@@ -75,7 +75,7 @@ public void CompareTo_NullUlid_ShouldReturnPositive()
 		var ulid = Ulid.New();
 
 		// Act
-		var comparisonResult = ulid.CompareTo(null);
+		var comparisonResult = ulid.CompareTo((object?)null);
 
 		// Assert
 		Assert.True(comparisonResult > 0);

src/ByteAether.Ulid.Tests/Ulid.Equatable.Tests.cs

@@ -65,7 +65,7 @@ public void Equals_Null_ShouldReturnFalse()
 		var ulid = Ulid.New();
 
 		// Act & Assert
-		Assert.False(ulid.Equals(null));
+		Assert.False(ulid.Equals((object?)null));
 	}
 
 	[Fact]
@@ -89,4 +89,4 @@ public void Equals_SameAsObject_ShouldReturnTrue()
 		// Act & Assert
 		Assert.True(ulid1.Equals((object)ulid2));
 	}
-}
+}

src/ByteAether.Ulid.Tests/Ulid.String.Tests.cs

@@ -3,7 +3,7 @@
 namespace ByteAether.Ulid.Tests;
 public class UlidStringTests
 {
-	private static readonly string _goodUlidString = "01F8MECHZX3TBDSZG8P8X7XRMM";
+	private const string _goodUlidString = "01F8MECHZX3TBDSZG8P8X7XRMM";
 
 	[Fact]
 	public void ToString_ShouldReturnExpectedString()
@@ -221,7 +221,7 @@ public void TryParse_ReadOnlySpanByte_InvalidInput_ShouldReturnFalse(string inpu
 	[Fact]
 	public void ToString_WrongLetters_ShouldReplaceWithCorrect()
 	{
-		// Crockford's Base32 subtitution test
+		// Crockford's Base32 substitution test
 		var inputChars = new[] { 'O', 'o', 'I', 'i', 'L', 'l', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm', 'n', 'p', 'q', 'r', 's', 't', 'v', 'w', 'x', 'y', 'z' };
 		var outputChars = new[] { '0', '0', '1', '1', '1', '1', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'M', 'N', 'P', 'Q', 'R', 'S', 'T', 'V', 'W', 'X', 'Y', 'Z' };
 
@@ -236,4 +236,4 @@ public void ToString_WrongLetters_ShouldReplaceWithCorrect()
 			Assert.Equal(outputString, resultString);
 		}
 	}
-}
+}

src/ByteAether.Ulid/PACKAGE.md

@@ -137,7 +137,7 @@ Create from existing `Guid`.
   `==`, `!=`, `<`, `<=`, `>`, `>=`.
 - Implements standard comparison and equality methods:\
   `CompareTo`, `Equals`, `GetHashCode`.
-- Provides implicit operators to and from `Guid`.
+- Provides implicit operators to and from `Guid` and `string`.
 
 ### GenerationOptions
 

src/ByteAether.Ulid/Ulid.String.cs

@@ -2,9 +2,6 @@
 using System.Diagnostics.CodeAnalysis;
 using System.Runtime.CompilerServices;
 using System.Text;
-#if !(NETSTANDARD2_1_OR_GREATER || NETCOREAPP)
-using System.Runtime.InteropServices;
-#endif
 
 namespace ByteAether.Ulid;
 
@@ -82,17 +79,28 @@ public readonly partial struct Ulid
 #else
 	[MethodImpl(MethodImplOptions.AggressiveInlining)]
 #endif
-	public readonly string ToString(string? format = null, IFormatProvider? formatProvider = null)
+	public readonly string ToString(string? format, IFormatProvider? formatProvider) => ToString();
+
+	/// <summary>
+	/// Returns a string representation of the current instance of <see cref="Ulid"/> in its canonical Crockford's Base32 format.'
+	/// </summary>
+	/// <returns>Crockford's Base32 representation of the ULID</returns>
+#if NET5_0_OR_GREATER
+	[SkipLocalsInit]
+#endif
+#if NETCOREAPP3_0_OR_GREATER
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+#else
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+#endif
+	public override readonly string ToString()
 	{
 #if NETSTANDARD2_1_OR_GREATER || NETCOREAPP
 		return string.Create(UlidStringLength, this, (span, ulid) => ulid.TryFill(span, _base32Chars));
 #else
 		Span<char> span = stackalloc char[UlidStringLength];
 		TryFill(span, _base32Chars);
-		unsafe
-		{
-			return new string((char*)Unsafe.AsPointer(ref MemoryMarshal.GetReference(span)), 0, UlidStringLength);
-		}
+		return span.ToString();
 #endif
 	}
 
@@ -385,4 +393,28 @@ private bool TryFill<T>(Span<T> span, T[] map)
 
 		return true;
 	}
+
+	/// <summary>
+	/// Allows implicit conversion of <see cref="Ulid"/> to <see cref="string"/>.
+	/// </summary>
+	/// <param name="ulid"></param>
+	/// <returns></returns>
+#if NETCOREAPP3_0_OR_GREATER
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+#else
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+#endif
+	public static implicit operator string(Ulid ulid) => ulid.ToString();
+
+	/// <summary>
+	/// Allows implicit conversion of <see cref="string"/> to <see cref="Ulid"/>.
+	/// </summary>
+	/// <param name="str"></param>
+	/// <returns></returns>
+#if NETCOREAPP3_0_OR_GREATER
+	[MethodImpl(MethodImplOptions.AggressiveInlining | MethodImplOptions.AggressiveOptimization)]
+#else
+	[MethodImpl(MethodImplOptions.AggressiveInlining)]
+#endif
+	public static implicit operator Ulid(string str) => Parse(str);
 }