minor refactoring and tests

Core.Tests/Base64UrlConversions/Decode.cs

@@ -7,7 +7,7 @@ public class Decode
     [InlineData(554121)]
     [InlineData(100454567)]
     [InlineData(3210589)]
-    public void WhenEncodedToString_ShouldBeDecodedToTheSameByteArray(int seed)
+    public void WhenBytesEncodedToString_ShouldBeDecodedToTheSameByteArray(int seed)
     {
         var rng = new Random(seed);
 
@@ -23,6 +23,43 @@ public class Decode
         }
     }
 
+    [Theory]
+    [InlineData(72121)]
+    [InlineData(554121)]
+    [InlineData(100454567)]
+    [InlineData(3210589)]
+    public void WhenLongEncodedToString_ShouldBeDecodedToTheSameLongArray(int seed)
+    {
+        var rng = new Random(seed);
+
+        for (int i = 1; i <= 512; i++)
+        {
+            var testLong = rng.NextInt64();
+
+            var resultString = Base64Url.Encode(testLong);
+            var resultLong = Base64Url.DecodeLong(resultString);
+
+            resultLong.Should().Be(testLong);
+        }
+    }
+
+    [Theory]
+    [InlineData("RgGxr0_n1ZI", -7866126844696657594L)]
+    [InlineData("sxAPfpKB5kY", 5108913293478531251L)]
+    [InlineData("lO4_uitvLCg", 2894810894091415188L)]
+    [InlineData("awxjIqZWz10", 6759716837247880299L)]
+    [InlineData("VjNe72vug4U", -8825948697371200682L)]
+    [InlineData("AAAAAAAAAAA", 0L)]
+    [InlineData("__________8", -1L)]
+    [InlineData("AQAAAAAAAAA", 1L)]
+    [InlineData("CgAAAAAAAAA", 10L)]
+    [InlineData("6AMAAAAAAAA", 1000L)]
+    public void WhenCalled_ShouldReturnValidLong(string testString, long expected)
+    {
+        var result = Base64Url.DecodeLong(testString);
+        result.Should().Be(expected);
+    }
+
     [Theory]
     [InlineData("5QrdUxDUVkCAEGw8pvLsEw", "53dd0ae5-d410-4056-8010-6c3ca6f2ec13")]
     [InlineData("6nE2uKQ4_0ar9kpmybgkdw", "b83671ea-38a4-46ff-abf6-4a66c9b82477")]
@@ -75,10 +112,23 @@ public class Decode
         action.Should().Throw<FormatException>();
     }
 
+    [Theory]
+    [InlineData("RgG&r0_n1ZI")]
+    [InlineData("sxA fpKB5kY")]
+    [InlineData("lO4_uitvL)g")]
+    [InlineData("awxjIqZ^z10")]
+    [InlineData("VjNe7!vug4U")]
+    [System.Diagnostics.CodeAnalysis.SuppressMessage("Performance", "CA1806:Do not ignore method results", Justification = "Test case")]
+    public void WhenCalledWithInvalidLongString_ShouldThrowFormatException(string testString)
+    {
+        Action action = () => Base64Url.DecodeLong(testString);
+        action.Should().Throw<FormatException>();
+    }
+
     [Theory]
     [InlineData(null)]
     [InlineData("")]
-    public void WhenCalledWithNullString_ShouldReturnEmptyArray(string testString)
+    public void WhenCalledWithNullString_ShouldReturnEmptyArray(string? testString)
     {
         Base64Url.Decode(testString).Should().BeEmpty();
     }

Core.Tests/Base64UrlConversions/Encode.cs

@@ -15,6 +15,23 @@ public class Encode
         result.Should().Be(expected);
     }
 
+    [Theory]
+    [InlineData("RgGxr0_n1ZI", -7866126844696657594L)]
+    [InlineData("sxAPfpKB5kY", 5108913293478531251L)]
+    [InlineData("lO4_uitvLCg", 2894810894091415188L)]
+    [InlineData("awxjIqZWz10", 6759716837247880299L)]
+    [InlineData("VjNe72vug4U", -8825948697371200682L)]
+    [InlineData("AAAAAAAAAAA", 0L)]
+    [InlineData("__________8", -1L)]
+    [InlineData("AQAAAAAAAAA", 1L)]
+    [InlineData("CgAAAAAAAAA", 10L)]
+    [InlineData("6AMAAAAAAAA", 1000L)]
+    public void WhenCalledWithLong_ShouldReturnValidString(string expected, long testLong)
+    {
+        var result = Base64Url.Encode(testLong);
+        result.Should().Be(expected);
+    }
+
     [Theory]
     [InlineData("IA", new byte[]{ 0x20, })]
     [InlineData("Ag", new byte[]{ 0x02, })]
@@ -33,7 +50,7 @@ public class Encode
     [Theory]
     [InlineData(new byte[] { })]
     [InlineData(null)]
-    public void WhenCalledWithEmptyByteArray_ShouldReturnEmptyString(byte[] testArray)
+    public void WhenCalledWithEmptyByteArray_ShouldReturnEmptyString(byte[]? testArray)
     {
         var actualBase32 = Base64Url.Encode(testArray);
         actualBase32.Should().Be(string.Empty);
@@ -42,7 +59,7 @@ public class Encode
     [Theory]
     [InlineData(new byte[] { })]
     [InlineData(null)]
-    public void WhenCalledWithEmptyByteArray_ShouldReturnZeroAndNotChangeOutput(byte[] testArray)
+    public void WhenCalledWithEmptyByteArray_ShouldReturnZeroAndNotChangeOutput(byte[]? testArray)
     {
         char[] output = ['1', '2', '3', '4'];
 

Core.Tests/GuidV8Tests/NewGuid.cs

@@ -2,15 +2,32 @@ namespace Just.Core.Tests.GuidV8Tests;
 
 public class NewGuid
 {
+    [Theory]
+    [InlineData(RngEntropy.Weak)]
+    [InlineData(RngEntropy.Strong)]
+    public void Version_And_Variant_Should_Be_Correct(RngEntropy entropy)
+    {
+        var rng = new Random(25);
+        var referenceTime = new DateTime(2020, 05, 17, 15, 36, 13, 771, DateTimeKind.Utc);
+
+        for (int i = 0; i < 2000; i++)
+        {
+            var timestamp = referenceTime.AddSeconds(rng.Next());
+            var result = GuidV8.NewGuid(timestamp, entropy);
+            result.Version.Should().Be(8);
+            (result.Variant & 0b1100).Should().Be(0b1000);
+        }
+    }
+
     [Theory]
     [InlineData(RngEntropy.Weak,
-        -25000000, -10000000, -5000000, -2000000, -1000000, -500000, -250000, -100000, -25000, -10000, -5000,
+        -25000000, -20000000, -10000000, -5000000, -2000000, -1000000, -500000, -250000, -100000, -25000, -10000, -5000,
         -2500, -1000, -500, -499, -497, -450, -300, -200, -50, -1, 0, 1, 2, 5, 10, 20, 50, 100, 200, 350, 500, 1000,
-        2500, 5000, 10000, 25000, 100000, 250000, 500000, 1000000, 2000000, 5000000, 10000000, 100000000, 250000000)]
+        2500, 5000, 10000, 25000, 100000, 250000, 500000, 1000000, 2000000, 5000000, 10000000, 20000000, 50000000, 100000000)]
     [InlineData(RngEntropy.Strong,
-        -25000000, -10000000, -5000000, -2000000, -1000000, -500000, -250000, -100000, -25000, -10000, -5000,
+        -25000000, -20000000, -10000000, -5000000, -2000000, -1000000, -500000, -250000, -100000, -25000, -10000, -5000,
         -2500, -1000, -500, -499, -497, -450, -300, -200, -50, -1, 0, 1, 2, 5, 10, 20, 50, 100, 200, 350, 500, 1000,
-        2500, 5000, 10000, 25000, 100000, 250000, 500000, 1000000, 2000000, 5000000, 10000000, 100000000, 250000000)]
+        2500, 5000, 10000, 25000, 100000, 250000, 500000, 1000000, 2000000, 5000000, 10000000, 20000000, 50000000, 100000000)]
     [InlineData(RngEntropy.Weak,
         -9863, -9740, -9214, -8878, -8674, -8652, -8640, -8565, -8518, -8449,
         -8390, -8193, -8108, -7808, -7501, -7203, -7133, -7020, -6983, -6855,
@@ -34,27 +51,27 @@ public class NewGuid
         6128, 6277, 6323, 6437, 6699, 6853, 7556, 7776, 7795, 8099,
         8336, 8592, 8682, 8683, 8818, 8904, 9375, 9466, 9551, 9708)]
     [InlineData(RngEntropy.Weak,
-        5635912, 6673780, 17277183, 17512959, 19098799, 21672621, 30581958, 30824885, 31874213, 35192781,
+        10024, 28660, 289641, 356015, 443164, 478759, 599586, 705860, 791271, 876512,
-        36337094, 37752116, 38387215, 39154682, 40525427, 52288093, 55218356, 59065156, 65231785, 75430932,
+        884503, 894899, 898584, 980136, 1007927, 1680328, 1690193, 1804615, 1847117, 2005534,
-        76289058, 79078058, 85770685, 85925884, 94726743, 94864163, 95781967, 96150006, 96482085, 102570414,
+        2106684, 2111936, 2252935, 2271396, 2298685, 2385409, 2414094, 2451706, 2549138, 2605538,
-        107768232, 110571078, 110680108, 117974892, 119800380, 126381415, 135895862, 140034471, 149039187, 150906974,
+        2864629, 2923476, 3004288, 3182875, 3266693, 3379019, 3542110, 3851467, 3871420, 4035463,
-        156853001, 160514433, 166446323, 170148965, 171759448, 176494242, 184537553, 188558155, 197194403, 197615804,
+        4316004, 4726381, 4814068, 4902666, 4979292, 4993443, 5117765, 5240585, 5249671, 5319528,
-        201195323, 202294490, 203040975, 203331457, 205016944, 213460258, 217072025, 217185345, 231344025, 232390198,
+        5387595, 5434544, 5504506, 5531264, 5546173, 5780381, 5889341, 6066328, 6167883, 6185073,
-        235053215, 240175073, 245030721, 252275255, 252310334, 277070940, 277359970, 280624756, 288601124, 292427106,
+        6299021, 6412136, 6621498, 6666562, 6741169, 6870279, 6949855, 6965427, 7153467, 7184150,
-        292563035, 299285016, 303834917, 310357836, 315078337, 316367236, 318311758, 318873972, 319675272, 321784171,
+        7300456, 7311381, 7413697, 7505235, 7802811, 7979134, 8053665, 8177676, 8260284, 8260773,
-        324204294, 327667283, 330287252, 338438172, 349863360, 360777768, 366398711, 368637150, 368776734, 371900343,
+        8269944, 8406526, 8442932, 8475162, 8555250, 8853347, 8861733, 8892200, 9069869, 9117839,
-        379094084, 379818879, 381448333, 381814627, 382393101, 382483709, 385600870, 389455134, 396115960, 399364095)]
+        9225445, 9245837, 9378644, 9497874, 9553625, 9650968, 9704053, 9713592, 9715054, 9735988)]
     [InlineData(RngEntropy.Strong,
-        5635912, 6673780, 17277183, 17512959, 19098799, 21672621, 30581958, 30824885, 31874213, 35192781,
+        10024, 28660, 289641, 356015, 443164, 478759, 599586, 705860, 791271, 876512,
-        36337094, 37752116, 38387215, 39154682, 40525427, 52288093, 55218356, 59065156, 65231785, 75430932,
+        884503, 894899, 898584, 980136, 1007927, 1680328, 1690193, 1804615, 1847117, 2005534,
-        76289058, 79078058, 85770685, 85925884, 94726743, 94864163, 95781967, 96150006, 96482085, 102570414,
+        2106684, 2111936, 2252935, 2271396, 2298685, 2385409, 2414094, 2451706, 2549138, 2605538,
-        107768232, 110571078, 110680108, 117974892, 119800380, 126381415, 135895862, 140034471, 149039187, 150906974,
+        2864629, 2923476, 3004288, 3182875, 3266693, 3379019, 3542110, 3851467, 3871420, 4035463,
-        156853001, 160514433, 166446323, 170148965, 171759448, 176494242, 184537553, 188558155, 197194403, 197615804,
+        4316004, 4726381, 4814068, 4902666, 4979292, 4993443, 5117765, 5240585, 5249671, 5319528,
-        201195323, 202294490, 203040975, 203331457, 205016944, 213460258, 217072025, 217185345, 231344025, 232390198,
+        5387595, 5434544, 5504506, 5531264, 5546173, 5780381, 5889341, 6066328, 6167883, 6185073,
-        235053215, 240175073, 245030721, 252275255, 252310334, 277070940, 277359970, 280624756, 288601124, 292427106,
+        6299021, 6412136, 6621498, 6666562, 6741169, 6870279, 6949855, 6965427, 7153467, 7184150,
-        292563035, 299285016, 303834917, 310357836, 315078337, 316367236, 318311758, 318873972, 319675272, 321784171,
+        7300456, 7311381, 7413697, 7505235, 7802811, 7979134, 8053665, 8177676, 8260284, 8260773,
-        324204294, 327667283, 330287252, 338438172, 349863360, 360777768, 366398711, 368637150, 368776734, 371900343,
+        8269944, 8406526, 8442932, 8475162, 8555250, 8853347, 8861733, 8892200, 9069869, 9117839,
-        379094084, 379818879, 381448333, 381814627, 382393101, 382483709, 385600870, 389455134, 396115960, 399364095)]
+        9225445, 9245837, 9378644, 9497874, 9553625, 9650968, 9704053, 9713592, 9715054, 9735988)]
     public void Guids_Differing_By_Minutes_Should_Be_Sortable(RngEntropy entropy, params int[] seconds)
     {
         var rng = new Random(25);
@@ -78,13 +95,13 @@ public class NewGuid
 
     [Theory]
     [InlineData(RngEntropy.Weak,
-        -250000000, -25000000, -10000000, -5000000, -2000000, -1000000, -500000, -250000, -100000, -25000, -10000, -5000,
+        -100000000, -25000000, -10000000, -5000000, -2000000, -1000000, -500000, -250000, -100000, -25000, -10000, -5000,
         -2500, -1000, -500, -499, -497, -450, -300, -200, -50, -1, 0, 1, 2, 5, 10, 20, 50, 100, 200, 350, 500, 1000,
-        2500, 5000, 10000, 25000, 100000, 250000, 500000, 1000000, 2000000, 5000000, 10000000, 100000000, 2100000000)]
+        2500, 5000, 10000, 25000, 100000, 250000, 500000, 1000000, 2000000, 5000000, 10000000, 100000000, 200000000)]
     [InlineData(RngEntropy.Strong,
-        -250000000, -25000000, -10000000, -5000000, -2000000, -1000000, -500000, -250000, -100000, -25000, -10000, -5000,
+        -100000000, -25000000, -10000000, -5000000, -2000000, -1000000, -500000, -250000, -100000, -25000, -10000, -5000,
         -2500, -1000, -500, -499, -497, -450, -300, -200, -50, -1, 0, 1, 2, 5, 10, 20, 50, 100, 200, 350, 500, 1000,
-        2500, 5000, 10000, 25000, 100000, 250000, 500000, 1000000, 2000000, 5000000, 10000000, 100000000, 2100000000)]
+        2500, 5000, 10000, 25000, 100000, 250000, 500000, 1000000, 2000000, 5000000, 10000000, 100000000, 200000000)]
     [InlineData(RngEntropy.Weak,
         -9863, -9740, -9214, -8878, -8674, -8652, -8640, -8565, -8518, -8449,
         -8390, -8193, -8108, -7808, -7501, -7203, -7133, -7020, -6983, -6855,

Core/Base32.cs

@@ -16,9 +16,9 @@ public static class Base32
             ? stackalloc char[outLength]
             : new char[outLength];
 
-        _ = Encode(input, output);
+        var size = Encode(input, output);
 
-        return new string(output);
+        return new string(output[..size]);
     }
 
     [Pure]
@@ -26,20 +26,31 @@ public static class Base32
     {
         if (input.IsEmpty) return 0;
 
+        int outputLength = 8 * ((input.Length + 4) / 5);
+        if (output.Length < outputLength)
+        {
+            throw new ArgumentException("Encoded input can not fit in output span.", nameof(output));
+        }
+
+        output = output[..outputLength];
+
         int i = 0;
         ReadOnlySpan<char> alphabet = Alphabet;
+        Span<byte> alphabetKeys = stackalloc byte[8];
+
         for (int offset = 0; offset < input.Length;)
         {
-            int numCharsToOutput = GetNextGroup(input, ref offset, out byte a, out byte b, out byte c, out byte d, out byte e, out byte f, out byte g, out byte h);
+            alphabetKeys.Clear();
+            int numCharsToOutput = GetNextGroup(input, ref offset, alphabetKeys);
 
-            output[i++] = (numCharsToOutput > 0) ? alphabet[a] : Padding;
+            output[i++] = (numCharsToOutput > 0) ? alphabet[alphabetKeys[0]] : Padding;
-            output[i++] = (numCharsToOutput > 1) ? alphabet[b] : Padding;
+            output[i++] = (numCharsToOutput > 1) ? alphabet[alphabetKeys[1]] : Padding;
-            output[i++] = (numCharsToOutput > 2) ? alphabet[c] : Padding;
+            output[i++] = (numCharsToOutput > 2) ? alphabet[alphabetKeys[2]] : Padding;
-            output[i++] = (numCharsToOutput > 3) ? alphabet[d] : Padding;
+            output[i++] = (numCharsToOutput > 3) ? alphabet[alphabetKeys[3]] : Padding;
-            output[i++] = (numCharsToOutput > 4) ? alphabet[e] : Padding;
+            output[i++] = (numCharsToOutput > 4) ? alphabet[alphabetKeys[4]] : Padding;
-            output[i++] = (numCharsToOutput > 5) ? alphabet[f] : Padding;
+            output[i++] = (numCharsToOutput > 5) ? alphabet[alphabetKeys[5]] : Padding;
-            output[i++] = (numCharsToOutput > 6) ? alphabet[g] : Padding;
+            output[i++] = (numCharsToOutput > 6) ? alphabet[alphabetKeys[6]] : Padding;
-            output[i++] = (numCharsToOutput > 7) ? alphabet[h] : Padding;
+            output[i++] = (numCharsToOutput > 7) ? alphabet[alphabetKeys[7]] : Padding;
         }
         return i;
     }
@@ -66,6 +77,11 @@ public static class Base32
         input = input.TrimEnd(Padding);
 
         var outputLength = 5 * ((input.Length + 7) / 8);
+        if (output.Length < outputLength)
+        {
+            throw new ArgumentException("Decoded input can not fit in output span.", nameof(output));
+        }
+
         output = output[..outputLength];
         output.Clear();
 
@@ -119,7 +135,7 @@ public static class Base32
 
     // returns the number of bytes that were output
     [Pure]
-    private static int GetNextGroup(ReadOnlySpan<byte> input, ref int offset, out byte a, out byte b, out byte c, out byte d, out byte e, out byte f, out byte g, out byte h)
+    private static int GetNextGroup(ReadOnlySpan<byte> input, ref int offset, Span<byte> alphabetKeys)
     {
         var retVal = (input.Length - offset) switch
         {
@@ -135,14 +151,14 @@ public static class Base32
         uint b4 = (offset < input.Length) ? input[offset++] : 0U;
         uint b5 = (offset < input.Length) ? input[offset++] : 0U;
 
-        a = (byte)(b1 >> 3);
+        alphabetKeys[0] = (byte)(b1 >> 3);
-        b = (byte)(((b1 & 0x07) << 2) | (b2 >> 6));
+        alphabetKeys[1] = (byte)(((b1 & 0x07) << 2) | (b2 >> 6));
-        c = (byte)((b2 >> 1) & 0x1f);
+        alphabetKeys[2] = (byte)((b2 >> 1) & 0x1f);
-        d = (byte)(((b2 & 0x01) << 4) | (b3 >> 4));
+        alphabetKeys[3] = (byte)(((b2 & 0x01) << 4) | (b3 >> 4));
-        e = (byte)(((b3 & 0x0f) << 1) | (b4 >> 7));
+        alphabetKeys[4] = (byte)(((b3 & 0x0f) << 1) | (b4 >> 7));
-        f = (byte)((b4 >> 2) & 0x1f);
+        alphabetKeys[5] = (byte)((b4 >> 2) & 0x1f);
-        g = (byte)(((b4 & 0x3) << 3) | (b5 >> 5));
+        alphabetKeys[6] = (byte)(((b4 & 0x3) << 3) | (b5 >> 5));
-        h = (byte)(b5 & 0x1f);
+        alphabetKeys[7] = (byte)(b5 & 0x1f);
 
         return retVal;
     }

Core/Base64Url.cs

@@ -1,24 +1,41 @@
+using System.Runtime.InteropServices;
+
 namespace Just.Core;
 
 public static class Base64Url
 {
+    private const char Padding = '=';
+
+    [Pure] public static long DecodeLong(ReadOnlySpan<char> value)
+    {
+        ArgumentOutOfRangeException.ThrowIfNotEqual(value.Length, 11);
+
+        Span<byte> longBytes = stackalloc byte[8];
+        Span<char> chars = stackalloc char[12];
+
+        value.CopyTo(chars);
+        chars[^1] = Padding;
+
+        ReplaceNonUrlChars(chars);
+
+        if (!Convert.TryFromBase64Chars(chars, longBytes, out int _))
+            throw new FormatException("Invalid Base64 string.");
+
+        return MemoryMarshal.Read<long>(longBytes);
+    }
+
     [Pure] public static Guid DecodeGuid(ReadOnlySpan<char> value)
     {
         ArgumentOutOfRangeException.ThrowIfNotEqual(value.Length, 22);
 
         Span<byte> guidBytes = stackalloc byte[16];
         Span<char> chars = stackalloc char[24];
+
         value.CopyTo(chars);
-        for (int i = 0; i < value.Length; i++)
+        chars[^2..].Fill(Padding);
-        {
+
-            switch (value[i])
+        ReplaceNonUrlChars(chars);
-            {
+
-                case '-': chars[i] = '+'; continue;
-                case '_': chars[i] = '/'; continue;
-                default: continue;
-            }
-        }
-        chars[^2..].Fill('=');
         if (!Convert.TryFromBase64Chars(chars, guidBytes, out int _))
             throw new FormatException("Invalid Base64 string.");
 
@@ -28,9 +45,9 @@ public static class Base64Url
     [Pure] public static byte[] Decode(ReadOnlySpan<char> input)
     {
         if (input.IsEmpty) return [];
-        
+
         Span<byte> output = stackalloc byte[3 * ((input.Length + 3) / 4)];
-        
+
         var size = Decode(input, output);
 
         return output[..size].ToArray();
@@ -40,28 +57,33 @@ public static class Base64Url
     {
         var padding = (4 - (value.Length & 3)) & 3;
         var charlen = value.Length + padding;
-        var outputBytes = charlen / 4;
+        var outputBytes = 3 * (charlen / 4);
         ArgumentOutOfRangeException.ThrowIfLessThan(output.Length, outputBytes);
         Span<char> chars = stackalloc char[charlen];
 
         value.CopyTo(chars);
-        for (int i = 0; i < value.Length; i++)
+        chars[^padding..].Fill(Padding);
-        {
+
-            switch (value[i])
+        ReplaceNonUrlChars(chars);
-            {
-                case '-': chars[i] = '+'; continue;
-                case '_': chars[i] = '/'; continue;
-                default: continue;
-            }
-        }
-        chars[^padding..].Fill('=');
 
         if (!Convert.TryFromBase64Chars(chars, output, out outputBytes))
             throw new FormatException("Invalid Base64 string.");
 
         return outputBytes;
     }
-    
+
+    [Pure] public static string Encode(in long id)
+    {
+        Span<byte> longBytes = stackalloc byte[8];
+        MemoryMarshal.Write(longBytes, id);
+
+        Span<char> chars = stackalloc char[12];
+        Convert.TryToBase64Chars(longBytes, chars, out int _);
+        ReplaceUrlChars(chars[..^1]);
+
+        return new string(chars[..^1]);
+    }
+
     [Pure] public static string Encode(in Guid id)
     {
         Span<byte> guidBytes = stackalloc byte[16];
@@ -69,15 +91,7 @@ public static class Base64Url
         Span<char> chars = stackalloc char[24];
         Convert.TryToBase64Chars(guidBytes, chars, out int _);
 
-        for (int i = 0; i < chars.Length - 2; i++)
+        ReplaceUrlChars(chars[..^2]);
-        {
-            switch (chars[i])
-            {
-                case '+': chars[i] = '-'; continue;
-                case '/': chars[i] = '_'; continue;
-                default: continue;
-            }
-        }
 
         return new string(chars[..^2]);
     }
@@ -86,7 +100,7 @@ public static class Base64Url
     {
         if (input.IsEmpty) return string.Empty;
 
-        int outLength = 8 * ((input.Length + 5) / 6);
+        int outLength = 4 * ((input.Length + 2) / 3);
         Span<char> output = stackalloc char[outLength];
 
         int strlen = Encode(input, output);
@@ -97,24 +111,47 @@ public static class Base64Url
     {
         if (input.IsEmpty) return 0;
 
-        var charlen = 8 * ((input.Length + 5) / 6);
+        var charlen = 4 * ((input.Length + 2) / 3);
         Span<char> chars = stackalloc char[charlen];
         Convert.TryToBase64Chars(input, chars, out int charsWritten);
 
-        int i;
+        int i = ReplaceUrlChars(chars[..charsWritten]);
-        for (i = 0; i < charsWritten; i++)
+        chars[..i].CopyTo(output);
+
+        return i;
+    }
+
+    private static int ReplaceUrlChars(Span<char> chars)
+    {
+        int i = 0;
+        for (; i < chars.Length; i++)
         {
             switch (chars[i])
             {
                 case '+': chars[i] = '-'; continue;
                 case '/': chars[i] = '_'; continue;
-                case '=': goto exitLoop;
+                case Padding: goto break_loop;
                 default: continue;
             }
         }
-        exitLoop:
+        break_loop:
-        chars[..i].CopyTo(output);
+        return i;
+    }
 
+    private static int ReplaceNonUrlChars(Span<char> chars)
+    {
+        int i = 0;
+        for (; i < chars.Length; i++)
+        {
+            switch (chars[i])
+            {
+                case '-': chars[i] = '+'; continue;
+                case '_': chars[i] = '/'; continue;
+                case Padding: goto break_loop;
+                default: continue;
+            }
+        }
+        break_loop:
         return i;
     }
 }

Core/Collections/ImmutableSequence.cs

@@ -8,18 +8,12 @@ public class ImmutableSequence<T> :
     IReadOnlyList<T>,
     IEquatable<ImmutableSequence<T>>
 {
-    private static readonly int InitialHash = typeof(ImmutableSequence<T>).GetHashCode();
     private static readonly Func<T?, T?, bool> CompareItem = EqualityComparer<T>.Default.Equals;
     private readonly ImmutableList<T> _values;
 
+    public ImmutableSequence() => _values = [];
     public ImmutableSequence(ImmutableList<T> values) => _values = values;
-    public ImmutableSequence() : this(ImmutableArray<T>.Empty)
+    public ImmutableSequence(IEnumerable<T> values) => _values = [..values];
-    {
-    }
-    public ImmutableSequence(IEnumerable<T> values)
-    {
-        _values = [..values];
-    }
     public ImmutableSequence(ReadOnlySpan<T> values) : this(ImmutableList.Create(values))
     {
     }
@@ -37,10 +31,10 @@ public class ImmutableSequence<T> :
         }
     }
 
-    protected virtual ImmutableSequence<T> ConstructNew(ImmutableList<T> values) => new(values);
+    protected virtual ImmutableSequence<T> ConstructNew(ImmutableList<T> values) => [..values];
 
-    public ImmutableSequence<T> Add(T value) => ConstructNew([.._values, value]);
+    public ImmutableSequence<T> Add(T value) => ConstructNew(_values.Add(value));
-    public ImmutableSequence<T> AddFront(T value) => ConstructNew([value, .._values]);
+    public ImmutableSequence<T> AddFront(T value) => ConstructNew(_values.Insert(0, value));
 
     public ImmutableList<T>.Enumerator GetEnumerator() => _values.GetEnumerator();
     IEnumerator<T> IEnumerable<T>.GetEnumerator() => ((IEnumerable<T>)_values).GetEnumerator();
@@ -75,7 +69,6 @@ public class ImmutableSequence<T> :
     public override int GetHashCode()
     {
         HashCode hash = new();
-        hash.Add(InitialHash);
 
         foreach (var value in _values)
         {

Core/GuidV8.cs

@@ -1,38 +1,42 @@
-using System.Runtime.InteropServices;
 using System.Security.Cryptography;
 
 namespace Just.Core;
 
 public static class GuidV8
 {
-    [Pure, MethodImpl(MethodImplOptions.AggressiveInlining)]
+    private const long TicksPrecision = TimeSpan.TicksPerMillisecond / 10;
+
+    [MethodImpl(MethodImplOptions.AggressiveInlining)]
     public static Guid NewGuid(RngEntropy entropy = RngEntropy.Strong) => NewGuid(DateTime.UtcNow, entropy);
 
-    [Pure]
     public static Guid NewGuid(DateTime dateTime, RngEntropy entropy = RngEntropy.Strong)
     {
         var epoch = dateTime.Subtract(DateTime.UnixEpoch);
-        var timestamp = epoch.Ticks / (TimeSpan.TicksPerMillisecond / 10);
+        var timestamp = epoch.Ticks / TicksPrecision;
 
-        Span<byte> ts = stackalloc byte[8];
+        uint tsHigh = (uint)((timestamp >> 16) & 0xFFFFFFFF);
-        MemoryMarshal.Write(ts, timestamp);
+        ushort tsLow = (ushort)(timestamp & 0x0000FFFF);
 
-        Span<byte> bytes = stackalloc byte[16];
+        Span<byte> bytes = stackalloc byte[10];
-
-        ts[0..2].CopyTo(bytes[4..6]);
-        ts[2..6].CopyTo(bytes[..4]);
 
         if (entropy == RngEntropy.Strong)
         {
-            RandomNumberGenerator.Fill(bytes[6..]);
+            RandomNumberGenerator.Fill(bytes);
         }
         else
         {
-            Random.Shared.NextBytes(bytes[6..]);
+            Random.Shared.NextBytes(bytes);
         }
 
-        bytes[7] = (byte)((bytes[7] & 0x0F) | 0x80);
+        bytes[0] = (byte)((bytes[0] & 0x0F) | 0x80); // Version 8
+        bytes[2] = (byte)((bytes[2] & 0x1F) | 0x80); // Variant 0b1000
 
-        return new Guid(bytes);
+        ushort version = (ushort)((bytes[0] << 8) | bytes[1]);
+
+        return new Guid(
+            tsHigh,
+            tsLow,
+            version,
+            bytes[2], bytes[3], bytes[4], bytes[5], bytes[6], bytes[7], bytes[8], bytes[9]);
     }
 }