Add WorldPosition struct for packets

Add WorldPosition struct that deserialises according to:
https://wiki.vg/Data_types#Type:Position

pumpkin-protocol/src/lib.rs

@@ -1,17 +1,19 @@
-use std::io::{self, Write};
+#![feature(test)]
+extern crate test;
 
 use bytebuf::{packet_id::Packet, ByteBuffer, DeserializerError};
 use bytes::Buf;
 use serde::{Deserialize, Serialize, Serializer};
+use std::io::{self, Write};
 use thiserror::Error;
 
 pub mod bytebuf;
 pub mod client;
-pub mod server;
-pub mod uuid;
-
 pub mod packet_decoder;
 pub mod packet_encoder;
+pub mod server;
+pub mod uuid;
+pub mod position;
 
 pub const CURRENT_MC_PROTOCOL: u32 = 767;
 

pumpkin-protocol/src/position.rs

@@ -0,0 +1,31 @@
+use serde::Deserialize;
+
+pub struct WorldPosition {
+    x: i32,
+    y: i32,
+    z: i32
+}
+
+impl<'de> Deserialize<'de> for WorldPosition {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+    where
+        D: serde::Deserializer<'de> {
+            struct Visitor;
+            impl<'a> serde::de::Visitor<'a> for Visitor {
+                type Value = WorldPosition;
+                fn expecting(&self, formatter: &mut std::fmt::Formatter) -> std::fmt::Result {
+                    formatter.write_str("An i64 int")
+                }
+                fn visit_i64<E>(self, v: i64) -> Result<Self::Value, E>
+                where
+                    E: serde::de::Error, {
+                        Ok(WorldPosition {
+                            x: (v >> 38) as i32,
+                            y: (v << 52 >> 52) as i32,
+                            z: (v << 26 >> 38) as i32
+                        })
+                    }
+            }
+            deserializer.deserialize_i64(Visitor)
+        }
+}