dev: make Memory::get pub (#2039)

* dev: make Memory::get `pub`

* edit changelog

* dev: expose get_maybe_relocatable instead

* add comment on borrowed variant

* add tests

Author: enitrat

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 #### Upcoming Changes
 
+* dev: add Memory::get_maybe_relocatable  [#2039](https://github.com/lambdaclass/cairo-vm/pull/2039)
+
 * refactor: remove duplicated get_val function [#2065](https://github.com/lambdaclass/cairo-vm/pull/2065)
 
 * fix: Always use a normal segment in first SegmentArena segment [#1845](https://github.com/lambdaclass/cairo-vm/pull/1845)

vm/src/vm/vm_memory/memory.rs

@@ -448,6 +448,19 @@ impl Memory {
         }
     }
 
+    /// Gets the value from memory address as a MaybeRelocatable value.
+    /// Returns an Error if the value at the memory address is missing or not a MaybeRelocatable.
+    pub fn get_maybe_relocatable(&self, key: Relocatable) -> Result<MaybeRelocatable, MemoryError> {
+        match self
+            .get(&key)
+            .ok_or_else(|| MemoryError::UnknownMemoryCell(Box::new(key)))?
+        {
+            // Note: the `Borrowed` variant will never occur.
+            Cow::Borrowed(maybe_rel) => Ok(maybe_rel.clone()),
+            Cow::Owned(maybe_rel) => Ok(maybe_rel),
+        }
+    }
+
     /// Inserts a value into memory
     /// Returns an error if the memory cell asignment is invalid
     pub fn insert_value<T: Into<MaybeRelocatable>>(
@@ -1194,6 +1207,29 @@ mod memory_tests {
         );
     }
 
+    #[test]
+    #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
+    fn get_maybe_relocatable_valid_relocatable() {
+        let memory = memory![((0, 0), (1, 0))];
+        assert_eq!(
+            memory
+                .get_maybe_relocatable(Relocatable::from((0, 0)))
+                .unwrap(),
+            Relocatable::from((1, 0)).into()
+        );
+    }
+
+    #[test]
+    fn get_maybe_relocatable_valid_integer() {
+        let memory = memory![((0, 0), 10)];
+        assert_eq!(
+            memory
+                .get_maybe_relocatable(Relocatable::from((0, 0)))
+                .unwrap(),
+            10.into()
+        );
+    }
+
     #[test]
     #[cfg_attr(target_arch = "wasm32", wasm_bindgen_test)]
     fn default_memory() {