base32 refactoring

Core/SeqId.cs

@@ -51,7 +51,7 @@ public sealed class SeqId(DateTime epoch)
     /// Thrown if more than 255 IDs generated in 1ms
     /// </exception>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public static long NextId(RngEntropy entropy = RngEntropy.Strong) => Default.Next(DateTime.UtcNow, entropy);
+    public static long NextId(RngEntropy entropy = RngEntropy.Strong) => Default.Next(entropy);
 
 #if NET9_0_OR_GREATER
     private readonly Lock _lock = new();
@@ -62,6 +62,7 @@ public sealed class SeqId(DateTime epoch)
     private readonly DateTime _epoch = epoch;
     private int _seqId = 0;
     private long _lastTimestamp = -1L;
+    private Func<DateTime> _defaultTimeFactory = static () => DateTime.UtcNow;
 
     /// <summary>
     /// Generates next ID using current UTC time
@@ -72,7 +73,7 @@ public sealed class SeqId(DateTime epoch)
     /// Thrown if more than 255 IDs generated in 1ms
     /// </exception>
     [MethodImpl(MethodImplOptions.AggressiveInlining)]
-    public long Next(RngEntropy entropy = RngEntropy.Strong) => Next(DateTime.UtcNow, entropy);
+    public long Next(RngEntropy entropy = RngEntropy.Strong) => Next(_defaultTimeFactory(), entropy);
 
     /// <summary>
     /// Generates next ID with explicit timestamp
@@ -104,7 +105,7 @@ public sealed class SeqId(DateTime epoch)
                 throw new InvalidOperationException("Refused to create new SeqId. Last timestamp is in the future.");
             }
 
-            if (_seqId == SeqMask)
+            if (_seqId > SeqMask)
             {
                 throw new IndexOutOfRangeException("Refused to create new SeqId. Sequence exhausted.");
             }
@@ -118,4 +119,6 @@ public sealed class SeqId(DateTime epoch)
 
         return timestamp | currentSeq | currentRand;
     }
+
+    internal void UnsafeReplaceDefaultTimeFactory(Func<DateTime> timeFactory) => _defaultTimeFactory = timeFactory;
 }