Fixed List_pop() head/tail NULL on len of 0

be-water-myFriend · Aug 23, 2010 · f588500 · f588500
1 parent 4af26b3
commit f588500
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Showing 2 changed files with 9 additions and 2 deletions.
diff --git a/src/list.c b/src/list.c
@@ -70,9 +70,12 @@ List_push(List *self, ListNode *node) {
 ListNode *
 List_pop(List *self) {
   if (!self->len) return NULL;
-  --self->len;
   ListNode *node = self->tail;
-  self->tail = node->prev;
+  if (--self->len) {
+    self->tail = node->prev;
+  } else {
+    self->tail = self->head = NULL;
+  }
   node->next = node->prev = NULL;
   return node;
 }

diff --git a/test.c b/test.c
@@ -221,9 +221,13 @@ test_List_pop() {
 
   assert(b == List_pop(list));
   assert(1 == list->len);
+  assert(a == list->head);
+  assert(a == list->tail);
 
   assert(a == List_pop(list));
   assert(0 == list->len);
+  assert(NULL == list->head);
+  assert(NULL == list->tail);
 
   assert(NULL == List_pop(list));
   assert(0 == list->len);