fix buffer out of range on small packets

src/minecraft/client/buffer.rs

@@ -2,6 +2,7 @@ use crate::minecraft::client::client::Client;
 
 use crate::minecraft::varint::varint_read;
 
+use std::cmp::min;
 use std::collections::VecDeque;
 use std::io;
 
@@ -77,12 +78,14 @@ impl Client {
         }
 
         let _ = self.buffer.extend(data);
+
+        let varint_buffer_len = min(self.buffer.len(), 5);
         
-        let mut varint_buffer: VecDeque<u8> = self.buffer[..5].to_vec().into();
+        let mut varint_buffer: VecDeque<u8> = self.buffer[..varint_buffer_len].to_vec().into();
         println!("varint_buffer : {:?}", varint_buffer);
 
         let expected_len = varint_read(&mut varint_buffer)?;
-        let varint_len = 5 - varint_buffer.len();
+        let varint_len = varint_buffer_len - varint_buffer.len();
 
         println!("expected len : {}, current len : {}", expected_len as usize, self.buffer.len());
         println!("buffer : {:?}", self.buffer);