From: Michael D. Lowis <mike@mdlowis.com>
Date: Thu, 31 Jul 2014 11:29:32 +0000 (-0400)
Subject: Implementation of list_insert_after
X-Git-Url: https://git.mdlowis.com/?a=commitdiff_plain;h=8a4c8b9e4772d84f6b73f8abdb67753bf804bbaf;p=projs%2Flibcds.git

Implementation of list_insert_after
---

diff --git a/source/list/list.c b/source/list/list.c
index d31a449..4adcdb4 100644
--- a/source/list/list.c
+++ b/source/list/list.c
@@ -50,9 +50,9 @@ bool list_empty(list_t* list)
 }
 
 list_node_t* list_prev(list_t* list, list_node_t* node){
-	list_node_t* prev = (NULL != list && NULL != node && list->head != node) ? list->head : NULL;
-	while(NULL != prev && prev->next != node) prev = prev->next;
-	return prev;
+    list_node_t* prev = (NULL != list && NULL != node && list->head != node) ? list->head : NULL;
+    while(NULL != prev && prev->next != node) prev = prev->next;
+    return prev;
 }
 
 list_node_t* list_at(list_t* list, size_t index)
@@ -181,6 +181,22 @@ list_node_t* list_insert( list_t* list, size_t index, void* contents)
     return new_node;
 }
 
+list_node_t* list_insert_after( list_t* list, list_node_t* node, void* contents)
+{
+    list_node_t* new_node = NULL;
+    if (node != NULL)
+    {
+        new_node = list_new_node(contents);
+        new_node->next = node->next;
+        node->next = new_node;
+        if (node == list->tail)
+        {
+            list->tail = new_node;
+        }
+    }
+    return new_node;
+}
+
 list_node_t* list_delete( list_t* list, size_t index)
 {
     list_node_t* node = NULL;
diff --git a/source/list/list.h b/source/list/list.h
index 8ee0b29..36d8cbb 100644
--- a/source/list/list.h
+++ b/source/list/list.h
@@ -185,6 +185,21 @@ list_node_t* list_pop_back( list_t* list );
  **/
 list_node_t* list_insert( list_t* list, size_t index, void* contents);
 
+/**
+ * @brief Inserts a new node in a linked list at the specified index.
+ *
+ * This function traverses the list to the desired index and inserts a new node
+ * with the given contents at that position. The node previously at the desired
+ * index becomes the child of the new node.
+ *
+ * @param list     The list to operate on.
+ * @param node     The node after which the item should be inserted.
+ * @param contents The contents of the new node.
+ *
+ * @return Pointer to the newly inserted node, NULL if index is out of range.
+ **/
+list_node_t* list_insert_after( list_t* list, list_node_t* node, void* contents);
+
 /**
  * @brief Deletes a node from the supplied list.
  *
@@ -202,7 +217,7 @@ list_node_t* list_delete(list_t* list, size_t index);
 /**
  * @brief Delete a node from the supplied list.
  *
- * This function differs from the above list_delete in that it is given a 
+ * This function differs from the above list_delete in that it is given a
  * pointer to a node to be deleted instead of an index.
  * //TODO: verify node->next should be set to NULL following successful deletion
  * //TODO: verify node->next should not be touched if node not present in list
diff --git a/tests/test_list.c b/tests/test_list.c
index f74f62b..483d3ef 100644
--- a/tests/test_list.c
+++ b/tests/test_list.c
@@ -477,6 +477,57 @@ TEST_SUITE(List) {
         mem_release(list);
     }
 
+    //-------------------------------------------------------------------------
+    // Test list_insert_after function
+    //-------------------------------------------------------------------------
+    TEST(Verify_insert_after_should_fail_to_insert_if_node_is_null)
+    {
+        list_t* list = list_new();
+        list_node_t* node = list_insert_after( list, NULL, mem_box(0x1234) );
+        CHECK( node == NULL );
+        mem_release(list);
+    }
+
+    TEST(Verify_insert_after_should_insert_after_the_head_node)
+    {
+        list_node_t* node;
+        list_t* list = list_new();
+        list_push_back(list, mem_box(0x1234));
+        node = list_insert_after( list, list_front(list), mem_box(0x1235) );
+        CHECK( node != NULL );
+        CHECK( node->next == NULL );
+        CHECK( list->tail == node );
+        mem_release(list);
+    }
+
+    TEST(Verify_insert_after_should_insert_after_the_tail_node)
+    {
+        list_node_t* node;
+        list_t* list = list_new();
+        list_push_back(list, mem_box(0x1234));
+        list_push_back(list, mem_box(0x1234));
+        node = list_insert_after( list, list_back(list), mem_box(0x1234) );
+        CHECK( node != NULL );
+        CHECK( node->next == NULL );
+        CHECK( list_at(list, 2) == node );
+        CHECK( list->tail == node );
+        mem_release(list);
+    }
+
+    TEST(Verify_insert_after_should_insert_after_an_inner_node)
+    {
+        list_node_t* node;
+        list_t* list = list_new();
+        list_push_back(list, mem_box(0x1234));
+        node = list_push_back(list, mem_box(0x1234));
+        list_push_back(list, mem_box(0x1234));
+        node = list_insert_after( list, node, mem_box(0x1234) );
+        CHECK( node != NULL );
+        CHECK( node->next == list->tail );
+        CHECK( node == list_at(list,2) );
+        mem_release(list);
+    }
+
     //-------------------------------------------------------------------------
     // Test list_delete function
     //-------------------------------------------------------------------------