support longer arrays in vec_ref (#367)

Support arrays up to 256 elements (hardcoded maximum just to avoid abuse) by combining multiple random_accesses.
The index is now split into low and high parts. It's a bit more inconvenient than using a single Target but this allows avoiding bit decomposition.

src/middleware/mod.rs

@@ -828,8 +828,8 @@ impl Params {
         Self::predicate_size() + STATEMENT_ARG_F_LEN * self.max_statement_args
     }
 
-    pub fn operation_size(&self) -> usize {
-        Self::operation_type_size() + OPERATION_ARG_F_LEN * self.max_operation_args
+    pub fn operation_size(&self, operation_arg_f_len: usize) -> usize {
+        Self::operation_type_size() + operation_arg_f_len * self.max_operation_args
     }
 
     pub const fn statement_tmpl_size(&self) -> usize {
@@ -844,6 +844,14 @@ impl Params {
         self.max_custom_batch_size * self.custom_predicate_size()
     }
 
+    /// Total size of the statement table including None, input statements from signed pods and
+    /// input recursive pods and new statements (public & private)
+    pub fn statement_table_size(&self) -> usize {
+        1 + self.max_input_signed_pods * self.max_signed_pod_values
+            + self.max_input_recursive_pods * self.max_input_pods_public_statements
+            + self.max_statements
+    }
+
     /// Parameters that define how the id is calculated
     pub fn id_params(&self) -> Vec<usize> {
         vec![

src/middleware/statement.rs

@@ -18,8 +18,6 @@ pub const KEY_SIGNER: &str = "_signer";
 // hash(KEY_TYPE) = [17948789436443445142, 12513915140657440811, 15878361618879468769, 938231894693848619]
 pub const KEY_TYPE: &str = "_type";
 pub const STATEMENT_ARG_F_LEN: usize = 8;
-pub const OPERATION_ARG_F_LEN: usize = 1;
-pub const OPERATION_AUX_F_LEN: usize = 2;
 
 #[derive(Clone, Copy, Debug, FromRepr, PartialEq, Eq, Hash, Serialize, Deserialize, JsonSchema)]
 pub enum NativePredicate {