From e49f425e43800b35fc7172d7f121b890439b69a8 Mon Sep 17 00:00:00 2001
From: jf-home <Orig5826@163.com>
Date: Wed, 30 Apr 2025 00:17:59 +0800
Subject: [PATCH] =?UTF-8?q?=E6=B7=BB=E5=8A=A0=E5=87=BD=E6=95=B0=E6=B3=A8?=
 =?UTF-8?q?=E9=87=8A?=
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---
 src/list.c       | 17 ++++++++++++++++-
 test/test_list.c | 12 +++++++++---
 2 files changed, 25 insertions(+), 4 deletions(-)

diff --git a/src/list.c b/src/list.c
index 640fab0..4c3929c 100644
--- a/src/list.c
+++ b/src/list.c
@@ -189,6 +189,21 @@ static void list_print(struct _list* self)
     }
 }
 
+/**
+ * @brief list slice
+ *  if index < 0, from the end of list. for example:
+ *  list[-1] is the last element in list.
+ * 
+ * @param self 
+ * @param start start index
+ * @param end end index 
+ * @param step step, if step < 0, return a reverse list.
+ * @return struct _list* 
+ *  a copy of the list, from start to end, step by step.
+ *      if step < 0, return a reverse list.
+ *      if step > 0, return a forward list.
+ *      if step == 0, return NULL.
+ */
 struct _list* list_slice(struct _list *self, int start, int end, int step)
 {
     assert(self != NULL);
@@ -260,7 +275,7 @@ struct _list* list_slice(struct _list *self, int start, int end, int step)
             list->insert(list, 0, (char*)self->obj + i * self->_obj_size);
         }
     }
-    
+
     return list;
 }
 
diff --git a/test/test_list.c b/test/test_list.c
index aa450d3..6be19b1 100644
--- a/test/test_list.c
+++ b/test/test_list.c
@@ -440,14 +440,20 @@ static void test_list_slice(void)
     }
 
     // python: list[0:] -> []
-    list2 = list->slice(list, 0, 0, 1); // if start == end
-    TEST_ASSERT_NULL(list2);
-
     list2 = list->slice(list, 1, 5, 0); // if step == 0
     TEST_ASSERT_NULL(list2);
 
+    list2 = list->slice(list, 0, 0, 1); // if start == end
+    TEST_ASSERT_NOT_NULL(list2);
+    TEST_ASSERT_TRUE(list2->empty(list2));
+
     list2 = list->slice(list, 1, 5, -1); // if start < end && step < 0
     TEST_ASSERT_NULL(list2);
+    TEST_ASSERT_TRUE(list2->empty(list2));
+
+    list2 = list->slice(list, 5, 1, 1); // if start > end && step > 0
+    TEST_ASSERT_NULL(list2);
+    TEST_ASSERT_TRUE(list2->empty(list2));
 
     // python: list[0:]
     list2 = list->slice(list, 0, len, 1);