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/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.");
 
@@ -40,21 +57,14 @@ 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.");
@@ -62,6 +72,18 @@ public static class Base64Url
         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)
         {