objlist: Implement non-growing slice assignment.

Slice value to assign can be only a list so far too.

1 files changed, 20 insertions, 0 deletions

diff --git a/py/objlist.c b/py/objlist.c
index 08c1716179..4432b2447b 100644
--- a/py/objlist.c
+++ b/py/objlist.c
@@ -173,6 +173,26 @@ STATIC mp_obj_t list_subscr(mp_obj_t self_in, mp_obj_t index, mp_obj_t value) {
         uint index_val = mp_get_index(self->base.type, self->len, index, false);
         return self->items[index_val];
     } else {
+#if MICROPY_ENABLE_SLICE
+        if (MP_OBJ_IS_TYPE(index, &mp_type_slice)) {
+            mp_obj_list_t *self = self_in;
+            assert(MP_OBJ_IS_TYPE(value, &mp_type_list));
+            mp_obj_list_t *slice = value;
+            machine_uint_t start, stop;
+            if (!mp_seq_get_fast_slice_indexes(self->len, index, &start, &stop)) {
+                assert(0);
+            }
+            int len_adj = slice->len - (stop - start);
+            //printf("Len adj: %d\n", len_adj);
+            assert(len_adj <= 0);
+            mp_seq_replace_slice_no_grow(self->items, self->len, start, stop, slice->items, slice->len, mp_obj_t);
+            // Clear "freed" elements at the end of list
+            mp_seq_clear(self->items, self->len + len_adj, self->len, sizeof(*self->items));
+            self->len += len_adj;
+            // TODO: apply allocation policy re: alloc_size
+            return mp_const_none;
+        }
+#endif
         mp_obj_list_store(self_in, index, value);
         return mp_const_none;
     }