Add DataInputStream::skipBytes

Author: dlunch

java_runtime/src/classes/java/io/data_input.rs

@@ -26,6 +26,7 @@ impl DataInput {
                 JavaMethodProto::new_abstract("readShort", "()S", Default::default()),
                 JavaMethodProto::new_abstract("readUnsignedShort", "()I", Default::default()),
                 JavaMethodProto::new_abstract("readUTF", "()Ljava/lang/String;", Default::default()),
+                JavaMethodProto::new_abstract("skipBytes", "(I)I", Default::default()),
             ],
             fields: vec![],
             access_flags: ClassAccessFlags::INTERFACE,

java_runtime/src/classes/java/io/data_input_stream.rs

@@ -31,6 +31,7 @@ impl DataInputStream {
                 JavaMethodProto::new("readShort", "()S", Self::read_short, Default::default()),
                 JavaMethodProto::new("readUnsignedShort", "()I", Self::read_unsigned_short, Default::default()),
                 JavaMethodProto::new("readUTF", "()Ljava/lang/String;", Self::read_utf, Default::default()),
+                JavaMethodProto::new("skipBytes", "(I)I", Self::skip_bytes, Default::default()),
             ],
             fields: vec![],
             access_flags: Default::default(),
@@ -221,4 +222,13 @@ impl DataInputStream {
 
         Ok(())
     }
+
+    async fn skip_bytes(jvm: &Jvm, _: &mut RuntimeContext, this: ClassInstanceRef<Self>, n: i32) -> Result<i32> {
+        tracing::debug!("java.io.DataInputStream::skipBytes({:?}, {:?})", &this, n);
+
+        let r#in = jvm.get_field(&this, "in", "Ljava/io/InputStream;").await?;
+        let skipped: i64 = jvm.invoke_virtual(&r#in, "skip", "(J)J", (n as i64,)).await?;
+
+        Ok(skipped as _)
+    }
 }

java_runtime/tests/classes/java/io/test_data_input_stream.rs

@@ -59,7 +59,7 @@ async fn test_data_input_stream_high_bit() -> Result<()> {
 
     let data = cast_vec(vec![
         0x81u8, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97,
-        0x98, 0x99, 0x9a, 0x9b, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16,
+        0x98, 0x99, 0x9a, 0x9b, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1a,
     ]);
     let data_len = data.len();
 
@@ -98,5 +98,14 @@ async fn test_data_input_stream_high_bit() -> Result<()> {
     jvm.array_raw_buffer(&array).await?.read(0, &mut buffer)?;
     assert_eq!(buffer, vec![0x10, 0x11, 0x12, 0x13, 0x14, 0x15]);
 
+    let skipped: i32 = jvm.invoke_virtual(&data_input_stream, "skipBytes", "(I)I", (2,)).await?;
+    assert_eq!(skipped, 2);
+
+    let short: i16 = jvm.invoke_virtual(&data_input_stream, "readShort", "()S", ()).await?;
+    assert_eq!(short, i16::from_be_bytes([0x18, 0x19]));
+
+    let available: i32 = jvm.invoke_virtual(&data_input_stream, "available", "()I", ()).await?;
+    assert_eq!(available, 1);
+
     Ok(())
 }