Add py_get_array_fixed_n function.

2 files changed, 13 insertions, 0 deletions

diff --git a/py/runtime.c b/py/runtime.c
index a1bd676367..2d8fa0206d 100644
--- a/py/runtime.c
+++ b/py/runtime.c
@@ -871,6 +871,18 @@ qstr py_get_qstr(py_obj_t arg) {
     }
 }
 
+py_obj_t *py_get_array_fixed_n(py_obj_t o_in, int n) {
+    if (IS_O(o_in, O_TUPLE) || IS_O(o_in, O_LIST)) {
+        py_obj_base_t *o = o_in;
+        if (o->u_tuple_list.len != n) {
+            nlr_jump(py_obj_new_exception_2(q_IndexError, "requested length %d but object has length %d", (void*)n, (void*)o->u_tuple_list.len));
+        }
+        return o->u_tuple_list.items;
+    } else {
+        nlr_jump(py_obj_new_exception_2(q_TypeError, "object '%s' is not a tuple or list", py_obj_get_type_str(o_in), NULL));
+    }
+}
+
 py_obj_t rt_load_const_str(qstr qstr) {
     DEBUG_OP_printf("load '%s'\n", qstr_str(qstr));
     return py_obj_new_str(qstr);
diff --git a/py/runtime.h b/py/runtime.h
index 98d77c8e72..33d7bed266 100644
--- a/py/runtime.h
+++ b/py/runtime.h
@@ -99,6 +99,7 @@ void py_obj_print(py_obj_t o);
 int rt_is_true(py_obj_t arg);
 int py_get_int(py_obj_t arg);
 qstr py_get_qstr(py_obj_t arg);
+py_obj_t *py_get_array_fixed_n(py_obj_t o, int n);
 py_obj_t py_obj_new_int(int value);
 py_obj_t rt_load_const_str(qstr qstr);
 py_obj_t rt_load_name(qstr qstr);