feat: implement VirtualMachine::is_accessed

Signed-off-by: Dori Medini <[email protected]>

refactor: implement get_cell to share code

Signed-off-by: Dori Medini <[email protected]>

chore: changelog entry

Signed-off-by: Dori Medini <[email protected]>

Author: dorimedini-starkware

CHANGELOG.md

@@ -2,6 +2,8 @@
 
 #### Upcoming Changes
 
+* feat: implement VirtualMachine::is_accessed [#2024](https://github.com/lambdaclass/cairo-vm/pull/2024)
+
 * fix: Keep None values in memory segments for the prover input info [#2021](https://github.com/lambdaclass/cairo-vm/pull/2021)
 
 * refactor: Clap attribute macros from #[clap(...)] to #[arg(...)] and #[command(...)] in v4.x [#2003] (https://github.com/lambdaclass/cairo-vm/pull/2003)

vm/src/vm/vm_core.rs

@@ -971,6 +971,10 @@ impl VirtualMachine {
         self.segments.memory.mem_eq(lhs, rhs, len)
     }
 
+    pub fn is_accessed(&self, addr: &Relocatable) -> Result<bool, MemoryError> {
+        self.segments.is_accessed(addr)
+    }
+
     ///Gets `n_ret` return values from memory
     pub fn get_return_values(&self, n_ret: usize) -> Result<Vec<MaybeRelocatable>, MemoryError> {
         let addr = (self.run_context.get_ap() - n_ret)

vm/src/vm/vm_memory/memory.rs

@@ -244,13 +244,7 @@ impl Memory {
     {
         let relocatable: Relocatable = key.try_into().ok()?;
 
-        let data = if relocatable.segment_index.is_negative() {
-            &self.temp_data
-        } else {
-            &self.data
-        };
-        let (i, j) = from_relocatable_to_indexes(relocatable);
-        let value = data.get(i)?.get(j)?.get_value()?;
+        let value = self.get_cell(relocatable)?.get_value()?;
         Some(Cow::Owned(self.relocate_value(&value).ok()?.into_owned()))
     }
 
@@ -648,6 +642,23 @@ impl Memory {
         Ok(values)
     }
 
+    fn get_cell(&self, addr: Relocatable) -> Option<&MemoryCell> {
+        let (i, j) = from_relocatable_to_indexes(addr);
+        let data = if addr.segment_index < 0 {
+            &self.temp_data
+        } else {
+            &self.data
+        };
+        data.get(i)?.get(j)
+    }
+
+    pub fn is_accessed(&self, addr: &Relocatable) -> Result<bool, MemoryError> {
+        Ok(self
+            .get_cell(*addr)
+            .ok_or(MemoryError::UnknownMemoryCell(Box::new(*addr)))?
+            .is_accessed())
+    }
+
     pub fn mark_as_accessed(&mut self, addr: Relocatable) {
         let (i, j) = from_relocatable_to_indexes(addr);
         let data = if addr.segment_index < 0 {

vm/src/vm/vm_memory/memory_segments.rs

@@ -200,6 +200,10 @@ impl MemorySegmentManager {
         }
     }
 
+    pub fn is_accessed(&self, addr: &Relocatable) -> Result<bool, MemoryError> {
+        self.memory.is_accessed(addr)
+    }
+
     /// Counts the memory holes (aka unaccessed memory cells) in memory
     /// # Parameters
     /// - `builtin_segment_indexes`: Set representing the segments indexes of the builtins initialized in the VM, except for the output builtin.