Add comments to SharpStreams

app/src/main/java/org/schabi/newpipe/streams/io/SharpInputStream.java

@@ -5,6 +5,10 @@ import androidx.annotation.NonNull;
 import java.io.IOException;
 import java.io.InputStream;
 
+/**
+ * Simply wraps a readable {@link SharpStream} allowing it to be used with built-in Java stuff that
+ * supports {@link InputStream}.
+ */
 public class SharpInputStream extends InputStream {
     private final SharpStream stream;
 

app/src/main/java/org/schabi/newpipe/streams/io/SharpOutputStream.java

@@ -5,6 +5,10 @@ import androidx.annotation.NonNull;
 import java.io.IOException;
 import java.io.OutputStream;
 
+/**
+ * Simply wraps a writable {@link SharpStream} allowing it to be used with built-in Java stuff that
+ * supports {@link OutputStream}.
+ */
 public class SharpOutputStream extends OutputStream {
     private final SharpStream stream;
 

app/src/main/java/org/schabi/newpipe/streams/io/SharpStream.java

@@ -5,7 +5,14 @@ import java.io.Flushable;
 import java.io.IOException;
 
 /**
- * Based on C#'s Stream class.
+ * Based on C#'s Stream class. SharpStream is a wrapper around the 2 different APIs for SAF
+ * ({@link us.shandian.giga.io.FileStreamSAF}) and non-SAF ({@link us.shandian.giga.io.FileStream}).
+ * It has both input and output like in C#, while in Java those are usually different classes.
+ * {@link SharpInputStream} and {@link SharpOutputStream} are simple classes that wrap
+ * {@link SharpStream} and extend respectively {@link java.io.InputStream} and
+ * {@link java.io.OutputStream}, since unfortunately a class can only extend one class, so that a
+ * sharp stream can be used with built-in Java stuff that supports {@link java.io.InputStream}
+ * or {@link java.io.OutputStream}.
  */
 public abstract class SharpStream implements Closeable, Flushable {
     public abstract int read() throws IOException;