make writing to heap directly private

src/heap.rs

@@ -20,6 +20,19 @@ impl HeapId {
 #[derive(Debug, Clone, PartialEq)]
 pub struct Heap(Vec<u8>);
 
+impl Heap {
+    fn write_u256(&mut self, start_address: u32, value: U256) {
+        let end = (start_address + 32) as usize;
+        if end > self.0.len() {
+            self.0.resize(end, 0);
+        }
+
+        let mut bytes = [0; 32];
+        value.to_big_endian(&mut bytes);
+        self.0[start_address as usize..end].copy_from_slice(&bytes);
+    }
+}
+
 impl HeapInterface for Heap {
     fn read_u256(&self, start_address: u32) -> U256 {
         self.read_u256_partially(start_address..start_address + 32)
@@ -33,16 +46,6 @@ impl HeapInterface for Heap {
         }
         U256::from_big_endian(&bytes)
     }
-    fn write_u256(&mut self, start_address: u32, value: U256) {
-        let end = (start_address + 32) as usize;
-        if end > self.0.len() {
-            self.0.resize(end, 0);
-        }
-
-        let mut bytes = [0; 32];
-        value.to_big_endian(&mut bytes);
-        self.0[start_address as usize..end].copy_from_slice(&bytes);
-    }
     fn read_range_big_endian(&self, range: Range<u32>) -> Vec<u8> {
         let end = (range.end as usize).min(self.0.len());
         let mut result = vec![0; range.len()];

src/instruction_handlers/heap_access.rs

@@ -15,7 +15,6 @@ use u256::U256;
 pub trait HeapInterface {
     fn read_u256(&self, start_address: u32) -> U256;
     fn read_u256_partially(&self, range: Range<u32>) -> U256;
-    fn write_u256(&mut self, start_address: u32, value: U256);
     fn read_range_big_endian(&self, range: Range<u32>) -> Vec<u8>;
 }
 

src/single_instruction_test/heap.rs

@@ -10,6 +10,13 @@ pub struct Heap {
     pub(crate) write: Option<(u32, U256)>,
 }
 
+impl Heap {
+    fn write_u256(&mut self, start_address: u32, value: U256) {
+        assert!(self.write.is_none());
+        self.write = Some((start_address, value));
+    }
+}
+
 impl HeapInterface for Heap {
     fn read_u256(&self, start_address: u32) -> U256 {
         assert!(self.write.is_none());
@@ -25,11 +32,6 @@ impl HeapInterface for Heap {
         U256::from_little_endian(&result)
     }
 
-    fn write_u256(&mut self, start_address: u32, value: U256) {
-        assert!(self.write.is_none());
-        self.write = Some((start_address, value));
-    }
-
     fn read_range_big_endian(&self, _: std::ops::Range<u32>) -> Vec<u8> {
         // This is wrong, but this method is only used to get the final return value.
         vec![]