bytecode evaluation

src/heap_area.rs

@@ -3,35 +3,65 @@ use std::collections::HashMap;
 use crate::stackframe::Value;
 use crate::classfile::{ AbstractTypeDescription, MethodInfo };
 
+#[derive(Debug)]
 pub struct HeapArea {
+    pub memory_capacity: usize,
+    pub memory_used: usize,
     pub object_area: ObjectArea,
     pub static_area: StaticArea,
 }
 
-type ObjectReference=u32;
+impl HeapArea {
+    pub fn new(memory_capacity: usize) -> Self {
+        HeapArea {
+            memory_capacity,
+            memory_used: 0,
+            object_area: ObjectArea::default(),
+            static_area: StaticArea::default(),
+        }
+    }
+}
 
+pub type ObjectReference=u32;
+
+const DEFAULT_COMPARTMENT_CAPACITY: usize = u16::MAX as usize;
+
+#[derive(Default, Debug)]
 pub struct ObjectArea {
     compartments: Vec<ObjectCompartment>,
 }
 
+#[derive(Debug)]
 pub struct ObjectCompartment {
-    objects: Box<[HeapObject]>,
+    objects: Box<[ObjectCompartmentEntry]>,
+    first_free: usize,
+    reserved_count: usize,
 }
 
+#[derive(Debug)]
+pub enum ObjectCompartmentEntry {
+    Valid(HeapObject),
+    Empty(usize), // next empty value
+}
+
+#[derive(Debug)]
 pub struct HeapObject {
     fields: Box<[ObjectField]>,
 }
 
+#[derive(Default, Debug)]
 pub struct StaticArea {
     static_objects: HashMap<String, StaticObject>,
 }
 
+#[derive(Debug)]
 pub struct StaticObject {
     pub class_index: usize,
     pub fields: Box<[ObjectField]>,
     pub methods: Box<[MethodInfo]>,
 }
 
+#[derive(Debug)]
 pub struct ObjectField {
     pub type_description: AbstractTypeDescription,
     pub value: Value,