Diff: singlylinkedlist.c

Revision:

49:6bb8b9a66642

Parent:

48:81866008bba4

--- a/singlylinkedlist.c	Tue Sep 11 11:15:08 2018 -0700
+++ b/singlylinkedlist.c	Thu Oct 04 09:17:16 2018 -0700
@@ -73,7 +73,7 @@
         if (result == NULL)
         {
             /* Codes_SRS_LIST_01_007: [If allocating the new list node fails, singlylinkedlist_add shall return NULL.] */
-            result = NULL;
+            /*return as is*/
         }
         else
         {
@@ -365,3 +365,45 @@
 
     return result;
 }
+
+LIST_ITEM_HANDLE singlylinkedlist_add_head(SINGLYLINKEDLIST_HANDLE list, const void* item)
+{
+    LIST_ITEM_HANDLE result;
+
+    /* Codes_SRS_LIST_02_001: [ If list is NULL then singlylinkedlist_add_head shall fail and return NULL. ]*/
+    if (list == NULL)
+    {
+        LogError("Invalid argument SINGLYLINKEDLIST_HANDLE list=%p", list);
+        result = NULL;
+    }
+    else
+    {
+        result = malloc(sizeof(LIST_ITEM_INSTANCE));
+
+        if (result == NULL)
+        {
+            /*Codes_SRS_LIST_02_003: [ If there are any failures then singlylinkedlist_add_head shall fail and return NULL. ]*/
+            LogError("failure in malloc");
+            /*return as is*/
+        }
+        else
+        {
+            /*Codes_SRS_LIST_02_002: [ singlylinkedlist_add_head shall insert item at head, succeed and return a non-NULL value. ]*/
+            result->item = item;
+            if (list->head == NULL)
+            {
+                result->next = NULL;
+                list->head = result;
+                list->tail = result;
+                
+            }
+            else
+            {
+                result->next = list->head;
+                list->head = result;
+            }
+        }
+    }
+
+    return result;
+}