diff --git a/src/utility/mod.rs b/src/utility/mod.rs
index 651aed7..33f3cdb 100644
--- a/src/utility/mod.rs
+++ b/src/utility/mod.rs
@@ -1 +1,2 @@
-pub mod list;
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+pub mod list;
+pub mod objaddr;
\ No newline at end of file
diff --git a/src/utility/objaddr.rs b/src/utility/objaddr.rs
new file mode 100644
index 0000000..d876056
--- /dev/null
+++ b/src/utility/objaddr.rs
@@ -0,0 +1,50 @@
+//! Burritos stores a data structure associating object ids with
+//! their references. The ObjAddr struct
+//! allows to maintain this data structure.
+
+use std::collections::HashMap;
+
+pub trait SynchObj { }
+
+/// Brief Definition of object identifiers:
+/// 
+/// The struct stores the list of created objects (Semaphore, Lock, ...) and for each of them
+/// associates an object identifier than can be passed to subsequent
+/// system calls on the object.
+/// 
+/// A method allows to detect of an object corresponding to a given
+/// identifier exists; this is used to check the parameters of system
+/// calls.
+struct ObjAddr<'a> {
+    last_id: i32,
+    map: HashMap<i32, &'a dyn SynchObj>
+}
+
+impl<'a> ObjAddr<'a> {
+    
+    /// Initializes and returns a ObjAddr struct
+    pub fn init() -> Self {
+        Self {
+            last_id: 3,
+            map: HashMap::<i32, &dyn SynchObj>::new()
+        }
+    }
+
+    /// Adds the **obj** SynchObj to self
+    pub fn add_object(&mut self, obj: &'a dyn SynchObj) -> i32 {
+        self.last_id = self.last_id + 1;
+        self.map.insert(self.last_id, obj);
+        self.last_id
+    }
+
+    /// Searches for an object of id **id** in self
+    pub fn search_object(&self, id: i32) -> Option<&& dyn SynchObj> {
+        self.map.get(&id)
+    }
+
+    /// Removes the object of id **id** from self if it exists
+    pub fn remove_object_from_key(&mut self, id: i32) {
+        self.map.remove(&id);
+    }
+
+}
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