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

src/static_data/libraries/growth_rate_library.rs

@@ -5,10 +5,12 @@ use hashbrown::HashMap;
 
 use crate::defines::LevelInt;
 use crate::static_data::GrowthRate;
-use crate::StringKey;
+use crate::{StringKey, ValueIdentifiable, ValueIdentifier};
 
 /// A library to store all growth rates.
 pub struct GrowthRateLibrary {
+    /// A unique identifier so we know what value this is.
+    identifier: ValueIdentifier,
     /// The underlying data structure.
     growth_rates: HashMap<StringKey, Box<dyn GrowthRate>>,
 }
@@ -17,6 +19,7 @@ impl GrowthRateLibrary {
     /// Instantiates a new growth rate library with a capacity.
     pub fn new(capacity: usize) -> GrowthRateLibrary {
         GrowthRateLibrary {
+            identifier: Default::default(),
             growth_rates: HashMap::with_capacity(capacity),
         }
     }
@@ -36,6 +39,12 @@ impl GrowthRateLibrary {
     }
 }
 
+impl ValueIdentifiable for GrowthRateLibrary {
+    fn value_identifier(&self) -> ValueIdentifier {
+        self.identifier
+    }
+}
+
 impl Debug for GrowthRateLibrary {
     fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
         f.debug_struct("GrowthRateLibrary").finish()