Add list reverse and length functions

jeraymond · Apr 6, 2012 · 57fa71e · 57fa71e
1 parent 54324a3
commit 57fa71e
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Showing 3 changed files with 70 additions and 3 deletions.
diff --git a/src/np_linkedlist.c b/src/np_linkedlist.c
@@ -93,3 +93,43 @@ void *np_linkedlist_pop(struct NpLinkedList *list)
   free(node);
   return item;
 }
+
+/**
+ Reverses the list.
+
+ @param list The list.
+ */
+void np_linkedlist_reverse(struct NpLinkedList *list)
+{
+  struct NpLinkedListNode *prev;
+  struct NpLinkedListNode *next;
+
+  prev = NULL;
+  while(list->head) {
+    next = list->head->next;
+    list->head->next = prev;
+    prev = list->head;
+    list->head = next;
+  }
+  list->head = prev;
+}
+
+/**
+ Determines the length of the list.
+
+ @param list The list.
+ @return the length of the list.
+ */
+unsigned np_linkedlist_length(struct NpLinkedList *list)
+{
+  struct NpLinkedListNode *node;
+  unsigned length;
+
+  length = 0;
+  node = list->head;
+  while (node) {
+    ++length;
+    node = node->next;
+  }
+  return length;
+}
diff --git a/src/np_linkedlist.h b/src/np_linkedlist.h
@@ -32,5 +32,7 @@ struct NpLinkedList *np_linkedlist_new();
 void np_linkedlist_free(struct NpLinkedList *list);
 void *np_linkedlist_push(struct NpLinkedList *list, void *item);
 void *np_linkedlist_pop(struct NpLinkedList *list);
+void np_linkedlist_reverse(struct NpLinkedList *list);
+unsigned np_linkedlist_length(struct NpLinkedList *list);
 
 #endif
diff --git a/test/np_linkedlist_test.c b/test/np_linkedlist_test.c
@@ -27,14 +27,39 @@ void np_linkedlist_test(void) {
   char *data1 = "The first data item";
   char *data2 = "The second data item";
 
+  /* push and pop */
   CU_ASSERT_NOT_EQUAL(NULL, list = np_linkedlist_new());
   CU_ASSERT_STRING_EQUAL(data1, np_linkedlist_push(list, data1));
-  CU_ASSERT_STRING_EQUAL(data1, (char *)np_linkedlist_pop(list));
+  CU_ASSERT_STRING_EQUAL(data1, np_linkedlist_pop(list));
   CU_ASSERT_EQUAL(NULL, np_linkedlist_pop(list));
   CU_ASSERT_STRING_EQUAL(data1, np_linkedlist_push(list, data1));
   CU_ASSERT_STRING_EQUAL(data2, np_linkedlist_push(list, data2));
-  CU_ASSERT_STRING_EQUAL(data2, (char *)np_linkedlist_pop(list));
-  CU_ASSERT_STRING_EQUAL(data1, (char *)np_linkedlist_pop(list));
+  CU_ASSERT_STRING_EQUAL(data2, np_linkedlist_pop(list));
+  CU_ASSERT_STRING_EQUAL(data1, np_linkedlist_pop(list));
   CU_ASSERT_EQUAL(NULL, np_linkedlist_pop(list));
+
+  /* reverse */
+  np_linkedlist_reverse(list);
+  CU_ASSERT_EQUAL(NULL, np_linkedlist_pop(list));
+
+  np_linkedlist_push(list, data1);
+  np_linkedlist_reverse(list);
+  CU_ASSERT_STRING_EQUAL(data1, np_linkedlist_pop(list));
+  CU_ASSERT_EQUAL(NULL, np_linkedlist_pop(list));
+
+  np_linkedlist_push(list, data1);
+  np_linkedlist_push(list, data2);
+  np_linkedlist_reverse(list);
+  CU_ASSERT_STRING_EQUAL(data1, np_linkedlist_pop(list));
+  CU_ASSERT_STRING_EQUAL(data2, np_linkedlist_pop(list));
+  CU_ASSERT_EQUAL(NULL, np_linkedlist_pop(list));
+
+  /* length */
+  CU_ASSERT_EQUAL(0, np_linkedlist_length(list));
+  np_linkedlist_push(list, data1);
+  CU_ASSERT_EQUAL(1, np_linkedlist_length(list));
+  np_linkedlist_push(list, data1);
+  CU_ASSERT_EQUAL(2, np_linkedlist_length(list));
+
   np_linkedlist_free(list);
 }