custom file stream implementation

MareSynchronosServer/MareSynchronosStaticFilesServer/Utils/BlockFileDataStream.cs

@@ -0,0 +1,70 @@
+namespace MareSynchronosStaticFilesServer.Utils;
+
+public sealed class BlockFileDataStream : Stream
+{
+    private readonly BlockFileDataSubstream[] _substreams;
+    private int _currentStreamIndex = 0;
+
+    public BlockFileDataStream(BlockFileDataSubstream[] substreams)
+    {
+        _substreams = substreams;
+    }
+
+    public override bool CanRead => true;
+    public override bool CanSeek => false;
+    public override bool CanWrite => false;
+    public override long Length => throw new NotSupportedException();
+    public override long Position { get => throw new NotSupportedException(); set => throw new NotSupportedException(); }
+
+    public override int Read(byte[] buffer, int offset, int count)
+    {
+        int totalRead = 0;
+        int currentOffset = 0;
+        int remainingCount = count;
+        while (totalRead < count && _currentStreamIndex < _substreams.Length)
+        {
+            var lastReadBytes = _substreams[_currentStreamIndex].Read(buffer, currentOffset, remainingCount);
+            if (lastReadBytes < remainingCount)
+            {
+                _substreams[_currentStreamIndex].Dispose();
+                _currentStreamIndex++;
+            }
+
+            totalRead += lastReadBytes;
+            currentOffset += lastReadBytes;
+            remainingCount -= lastReadBytes;
+        }
+
+        return totalRead;
+    }
+
+    protected override void Dispose(bool disposing)
+    {
+        base.Dispose(disposing);
+        foreach (var substream in _substreams)
+        {
+            // probably unnecessary but better safe than sorry
+            substream.Dispose();
+        }
+    }
+
+    public override void Flush()
+    {
+        throw new NotSupportedException();
+    }
+
+    public override long Seek(long offset, SeekOrigin origin)
+    {
+        throw new NotSupportedException();
+    }
+
+    public override void SetLength(long value)
+    {
+        throw new NotSupportedException();
+    }
+
+    public override void Write(byte[] buffer, int offset, int count)
+    {
+        throw new NotSupportedException();
+    }
+}