feat(starknet_os): implement load_entry_points_to_contract_class_stru…

…ct for load_inner_class hint (#4640)

crates/starknet_os/src/hints/hint_implementation/deprecated_compiled_class.rs

@@ -1 +1,3 @@
 pub mod implementation;
+#[allow(dead_code)]
+pub mod utils;

crates/starknet_os/src/hints/hint_implementation/deprecated_compiled_class/utils.rs

@@ -0,0 +1,59 @@
+use cairo_vm::types::relocatable::{MaybeRelocatable, Relocatable};
+use cairo_vm::vm::vm_core::VirtualMachine;
+use starknet_api::contract_class::EntryPointType;
+use starknet_api::deprecated_contract_class::ContractClass;
+use starknet_types_core::felt::Felt;
+
+use crate::hints::error::OsHintResult;
+use crate::hints::vars::CairoStruct;
+use crate::vm_utils::{insert_value_to_nested_field, IdentifierGetter};
+
+#[allow(clippy::too_many_arguments)]
+/// Loads the entry points of a deprecated contract class to a contract class struct, given a
+/// specific entry point type.
+fn load_entry_points_to_contract_class_struct<IG: IdentifierGetter>(
+    deprecated_class: &ContractClass,
+    entry_point_type: &EntryPointType,
+    class_base: Relocatable,
+    var_type: CairoStruct,
+    vm: &mut VirtualMachine,
+    identifier_getter: &IG,
+    entry_points_field: String,
+    num_entry_points_field: String,
+) -> OsHintResult {
+    let empty_vec = Vec::new();
+    let entry_points =
+        deprecated_class.entry_points_by_type.get(entry_point_type).unwrap_or(&empty_vec);
+
+    let flat_entry_point_data: Vec<MaybeRelocatable> = entry_points
+        .iter()
+        .flat_map(|entry_point| {
+            vec![
+                MaybeRelocatable::from(entry_point.selector.0),
+                MaybeRelocatable::from(Felt::from(entry_point.offset.0)),
+            ]
+        })
+        .collect();
+
+    insert_value_to_nested_field(
+        class_base,
+        var_type,
+        vm,
+        &[num_entry_points_field],
+        identifier_getter,
+        Felt::from(entry_points.len()),
+    )?;
+
+    let flat_entry_point_data_base = vm.add_memory_segment();
+    vm.load_data(flat_entry_point_data_base, &flat_entry_point_data)?;
+    insert_value_to_nested_field(
+        class_base,
+        var_type,
+        vm,
+        &[entry_points_field],
+        identifier_getter,
+        flat_entry_point_data_base,
+    )?;
+
+    Ok(())
+}

crates/starknet_os/src/hints/vars.rs

@@ -147,6 +147,8 @@ impl Const {
         Self::AliasContractAddress.fetch_as(constants)
     }
 }
+
+#[derive(Copy, Clone)]
 pub enum CairoStruct {
     CompiledClassFact,
     DeprecatedCompiledClass,

crates/starknet_os/src/vm_utils.rs

@@ -138,7 +138,6 @@ fn fetch_nested_fields_address<IG: IdentifierGetter>(
 }
 
 /// Inserts a value to a nested field of a cairo variable given a base address.
-#[allow(dead_code)]
 pub(crate) fn insert_value_to_nested_field<IG: IdentifierGetter, T: Into<MaybeRelocatable>>(
     base_address: Relocatable,
     var_type: CairoStruct,