Rework of FFI, adding a value identifier, so we can keep knowledge of data even when data moves.

src/utils/mod.rs

@@ -2,9 +2,12 @@
 pub use random::Random;
 #[doc(inline)]
 pub use string_key::StringKey;
+#[doc(inline)]
+pub use value_identifier::*;
 
 /// The random module defines a RNG implementation used in pkmn_lib
 mod random;
 /// The string_key module defines a custom string handling for reduced allocations and fast lookups
 /// and equality checks.
 mod string_key;
+mod value_identifier;

src/utils/value_identifier.rs

@@ -0,0 +1,22 @@
+use std::sync::atomic::{AtomicUsize, Ordering};
+
+static CURRENT: AtomicUsize = AtomicUsize::new(1);
+
+/// An extremely basic way to identify a piece of data.
+#[derive(Debug, Copy, Clone, Ord, PartialOrd, Eq, PartialEq)]
+#[repr(C)]
+pub struct ValueIdentifier(usize);
+
+impl Default for ValueIdentifier {
+    fn default() -> Self {
+        Self {
+            0: CURRENT.fetch_add(1, Ordering::SeqCst),
+        }
+    }
+}
+
+/// An object with a specific identifier.
+pub trait ValueIdentifiable {
+    /// Get the identifier for the current object.
+    fn value_identifier(&self) -> ValueIdentifier;
+}