feat(batch15): complete msgblock and consumer file store port

dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StoreEnumExtensions.cs

@@ -69,6 +69,22 @@ public static class StoreEnumExtensions
         };
     }
 
+    public static (byte[]? Buffer, Exception? Error) Decompress(this StoreCompression alg, byte[] buf)
+    {
+        ArgumentNullException.ThrowIfNull(buf);
+
+        const int checksumSize = FileStoreDefaults.RecordHashSize;
+        if (buf.Length < checksumSize)
+            return (null, new InvalidDataException("compressed buffer is too short"));
+
+        return alg switch
+        {
+            StoreCompression.NoCompression => (buf, null),
+            StoreCompression.S2Compression => DecompressS2(buf, checksumSize),
+            _ => (null, new InvalidOperationException("compression algorithm not known")),
+        };
+    }
+
     private static (byte[]? Buffer, Exception? Error) CompressS2(byte[] buf, int checksumSize)
     {
         try
@@ -86,4 +102,22 @@ public static class StoreEnumExtensions
             return (null, new IOException("error writing to compression writer", ex));
         }
     }
+
+    private static (byte[]? Buffer, Exception? Error) DecompressS2(byte[] buf, int checksumSize)
+    {
+        try
+        {
+            var bodyLength = buf.Length - checksumSize;
+            var decompressedBody = Snappy.Decode(buf.AsSpan(0, bodyLength));
+
+            var output = new byte[decompressedBody.Length + checksumSize];
+            Buffer.BlockCopy(decompressedBody, 0, output, 0, decompressedBody.Length);
+            Buffer.BlockCopy(buf, bodyLength, output, decompressedBody.Length, checksumSize);
+            return (output, null);
+        }
+        catch (Exception ex)
+        {
+            return (null, new IOException("error reading compression reader", ex));
+        }
+    }
 }

reports/current.md

@@ -1,6 +1,6 @@
 # NATS .NET Porting Status Report
 
-Generated: 2026-02-28 23:34:28 UTC
+Generated: 2026-02-28 23:39:18 UTC
 
 ## Modules (12 total)
 
@@ -13,10 +13,10 @@ Generated: 2026-02-28 23:34:28 UTC
 | Status | Count |
 |--------|-------|
 | complete | 22 |
-| deferred | 1698 |
+| deferred | 1697 |
 | n_a | 24 |
 | stub | 1 |
-| verified | 1928 |
+| verified | 1929 |
 
 ## Unit Tests (3257 total)
 
@@ -35,4 +35,4 @@ Generated: 2026-02-28 23:34:28 UTC
 
 ## Overall Progress
 
-**3601/6942 items complete (51.9%)**
+**3602/6942 items complete (51.9%)**