documentation update

Core/Base64Url.cs

@@ -2,10 +2,15 @@ using System.Runtime.InteropServices;
 
 namespace Just.Core;
 
+/// <summary>
+/// URL-safe Base64 encoder/decoder for bytes, <see cref="long"/>, and <see cref="Guid"/>.
+/// Uses the standard Base64Url character set (- and _ instead of + and /), padding stripped by default.
+/// </summary>
 public static class Base64Url
 {
     private const char Padding = '=';
 
+    /// <summary>Decodes an 11-character Base64Url string into a <see cref="long"/>.</summary>
     [Pure] public static long DecodeLong(ReadOnlySpan<char> value)
     {
         ArgumentOutOfRangeException.ThrowIfNotEqual(value.Length, 11);
@@ -24,6 +29,7 @@ public static class Base64Url
         return MemoryMarshal.Read<long>(longBytes);
     }
 
+    /// <summary>Decodes a 22-character Base64Url string into a <see cref="Guid"/>.</summary>
     [Pure] public static Guid DecodeGuid(ReadOnlySpan<char> value)
     {
         ArgumentOutOfRangeException.ThrowIfNotEqual(value.Length, 22);
@@ -42,6 +48,7 @@ public static class Base64Url
         return new Guid(guidBytes);
     }
 
+    /// <summary>Decodes a Base64Url string into a byte array.</summary>
     [Pure] public static byte[] Decode(ReadOnlySpan<char> input)
     {
         if (input.IsEmpty) return [];
@@ -53,6 +60,7 @@ public static class Base64Url
         return output[..size].ToArray();
     }
 
+    /// <summary>Decodes a Base64Url string into a pre-allocated byte span. Returns the number of bytes written.</summary>
     [Pure] public static int Decode(ReadOnlySpan<char> value, Span<byte> output)
     {
         var padding = (4 - (value.Length & 3)) & 3;
@@ -72,6 +80,7 @@ public static class Base64Url
         return outputBytes;
     }
 
+    /// <summary>Encodes a <see cref="long"/> into an 11-character Base64Url string.</summary>
     [Pure] public static string Encode(in long id)
     {
         Span<byte> longBytes = stackalloc byte[8];
@@ -84,6 +93,7 @@ public static class Base64Url
         return new string(chars[..^1]);
     }
 
+    /// <summary>Encodes a <see cref="Guid"/> into a 22-character Base64Url string.</summary>
     [Pure] public static string Encode(in Guid id)
     {
         Span<byte> guidBytes = stackalloc byte[16];
@@ -96,6 +106,7 @@ public static class Base64Url
         return new string(chars[..^2]);
     }
 
+    /// <summary>Encodes a byte span into a Base64Url string.</summary>
     [Pure] public static string Encode(ReadOnlySpan<byte> input)
     {
         if (input.IsEmpty) return string.Empty;
@@ -107,6 +118,7 @@ public static class Base64Url
         return new string(output[..strlen]);
     }
 
+    /// <summary>Encodes a byte span into a pre-allocated char span. Returns the number of characters written.</summary>
     [Pure] public static int Encode(ReadOnlySpan<byte> input, Span<char> output)
     {
         if (input.IsEmpty) return 0;