Add CompressSave, with Chinese instructions in READMEs

CompressSave/LZ4Wrap/BlackHoleStream.cs

@@ -0,0 +1,50 @@
+using System;
+using System.IO;
+
+namespace CompressSave.LZ4Wrap;
+
+class BlackHoleStream : Stream
+{
+    private long length;
+
+    public override bool CanRead => true;
+
+    public override bool CanSeek => false;
+
+    public override bool CanWrite => true;
+
+    public override long Length => length;
+
+    public override long Position { get; set; }
+
+    public BlackHoleStream()
+    {
+
+    }
+
+    public override void Flush()
+    {
+        ;
+    }
+
+    public override int Read(byte[] buffer, int offset, int count)
+    {
+        return count;
+    }
+
+    public override long Seek(long offset, SeekOrigin origin)
+    {
+        throw new NotImplementedException();
+    }
+
+    public override void SetLength(long value)
+    {
+        length = value;
+    }
+    public byte[] testBuffer = new byte[1024 * 1024];
+
+    public override void Write(byte[] buffer, int offset, int count)
+    {
+        Array.Copy(buffer, offset, testBuffer, 0, Math.Min(count, testBuffer.Length));
+    }
+}