Adding key and search to list

src/util/list.c

@@ -22,6 +22,7 @@
 #endif
 
 #include <string.h>
+#include <time.h>
 #include <assert.h>
 
 #include "list.h"
@@ -29,6 +30,7 @@
 
 typedef struct list_node_s {
     void *data;
+    int key;
     struct list_node_s *next;
 } list_node_t;
 
@@ -42,6 +44,9 @@ typedef struct list_s {
 } list_t;
 
 
+// local declarations
+int gen_key();
+
 list_t *create_list(size_t elementSize, freeFunction freeFn)
 {
     list_t *list;
@@ -67,12 +72,14 @@ void delete_list(list_t *list)
     free(list);
 }
 
-void prepend_list(list_t *list, void *element)
+int prepend_list(list_t *list, void *element)
 {
     list_node_t *node = malloc(sizeof(list_node_t));
     node->data = malloc(list->elementSize);
     memcpy(node->data, element, list->elementSize);
 
+    node->key = gen_key();
+
     node->next = list->head;
     list->head = node;
 
@@ -82,14 +89,18 @@ void prepend_list(list_t *list, void *element)
     }
 
     list->logicalLength++;
+
+    return node->key;
 }
 
-void append_list(list_t *list, void *element)
+int append_list(list_t *list, void *element)
 {
 	list_node_t *node = malloc(sizeof(list_node_t));
     node->data = malloc(list->elementSize);
     node->next = NULL;
 
+    node->key = gen_key();
+
     memcpy(node->data, element, list->elementSize);
 
     if(list->logicalLength == 0) {
@@ -100,8 +111,11 @@ void append_list(list_t *list, void *element)
     }
 
     list->logicalLength++;
+
+    return node->key;
 }
 
+
 void for_each_list(list_t *list, listIterator iterator)
 {
     assert(iterator != NULL);
@@ -110,15 +124,13 @@ void for_each_list(list_t *list, listIterator iterator)
     bool result = true;
 
 	while(node != NULL && result) {
-		result = (iterator);
+		result = iterator(node);
         node = node->next;
     }
 }
 
 list_node_t *head_list(list_t *list, bool removeFromList)
-//
 // Warning: When node is removed caller is responsible for freeing it.
-//
 {
 //    assert(list->head != NULL);
 
@@ -152,11 +164,31 @@ list_node_t *get_nth_list(list_t *list, int index)
 		return lnode;
 }
 
+list_node_t *search_list(list_t *list, int key)
+// Naive list search. Will not perform for large lists.
+{
+    list_node_t *lnode = first_list(list);
+
+    while (done_list(lnode)) {
+
+        if (get_key(lnode) == key)
+            return lnode;
+
+        lnode = next_list(lnode);
+    }
+    return NULL;
+}
+
 int size_list(list_t *list)
 {
     return list->logicalLength;
 }
 
+int get_key(list_node_t *lnode)
+{
+    return lnode->key;
+}
+
 void *get_data(list_node_t *lnode)
 {
     return lnode->data;
@@ -175,3 +207,12 @@ void delete_node(list_t *list, list_node_t *lnode)
     free(lnode->data);
     free(lnode);
 }
+
+
+// local functions
+
+int gen_key()
+// Naive key generator. No guarentee of uniqueness
+{
+    return rand();
+}

src/util/list.h

@@ -46,14 +46,14 @@ with each node’s data pointer.
 void delete_list(list_t *list);
 
 /**
-@brief Adds a node to the head of the list.
+@brief Adds a node to the head of the list and returns its key.
 */
-void prepend_list(list_t *list, void *element);
+int prepend_list(list_t *list, void *element);
 
 /**
-@brief Adds a node to the tail of the list.
+@brief Adds a node to the tail of the list and returns its key.
 */
-void append_list(list_t *list, void *element);
+int append_list(list_t *list, void *element);
 
 /**
 @brief Returns the number of items in the list.
@@ -66,6 +66,11 @@ int size_list(list_t *list);
 */
 void *get_data(list_node_t *lnode);
 
+/**
+@brief Returns list node's key value.
+*/
+int get_key(list_node_t *lnode);
+
 /**
 @brief Returns next list node.
 */
@@ -98,6 +103,10 @@ list_node_t *tail_list(list_t *list);
 */
 list_node_t *get_nth_list(list_t *list, int index);
 
+/**
+@brief Returns the list node with the given key or NULL.
+*/
+list_node_t *search_list(list_t *list, int key);
 
 //
 // Iterator first/done/next operations

tests/util/test_list.cpp

@@ -13,7 +13,9 @@
  ******************************************************************************
 */
 
+#include <stdlib.h>
 #include <string.h>
+#include <time.h>
 
 #define BOOST_TEST_MODULE list
 #include <boost/test/unit_test.hpp>
@@ -35,7 +37,7 @@ int *get_int_data(list_node_t *lnode) {
 
 bool iterate_int(list_node_t *lnode)
 {
-    printf("Found value: %d\n", *get_int_data(lnode));
+    printf("At Key: %d  Found value: %d\n", get_key(lnode), *get_int_data(lnode));
     return true;
 }
 
@@ -57,16 +59,23 @@ BOOST_AUTO_TEST_CASE(test_int_list){
     int i, numbers = 10;
     list_t *list = NULL;
 
+    int key[10 + 1];
+
+    srand((unsigned int)time(0));
+
     list = create_list(sizeof(int), NULL);
 
     for(i = 1; i <= numbers; i++) {
-        append_list(list, &i);
+        key[i] = append_list(list, &i);
     }
     BOOST_CHECK(size_list(list) == 10);
 
 	listIterator iterator = (listIterator)iterate_int;
     for_each_list(list, iterator);
 
+    list_node_t *lnode = search_list(list, key[5]);
+    BOOST_CHECK(get_key(lnode) == key[5]);
+
     delete_list(list);
 }
 
@@ -179,9 +188,15 @@ bool iterate_test_data(list_node_t *lnode)
 }
 
 
+char *get_name(list_node_t *lnode)
+{
+    return get_test_data(lnode)->name;
+}
 
 BOOST_AUTO_TEST_CASE(test_struct_list){
 
+    int key;
+
     list_t *list = NULL;
     list = create_list(sizeof(test_data_t *), delete_test_data);
 
@@ -190,7 +205,7 @@ BOOST_AUTO_TEST_CASE(test_struct_list){
     append_list(list, &data);
 
     data = create_test_data(2, "Kevin");
-    append_list(list, &data);
+    key = append_list(list, &data);
 
     data = create_test_data(3, "Michael");
     append_list(list, &data);
@@ -202,16 +217,11 @@ BOOST_AUTO_TEST_CASE(test_struct_list){
     for_each_list(list, iterator);
 
 
-    list_node_t *lnode;
-    // Iterate over list while maintaining containment of list abstraction
-    for (lnode = first_list(list); done_list(lnode); lnode = next_list(lnode)) {
-        test_data_t *test_data = get_test_data(lnode);
+    // locate a list node by a key
+    printf("Found %s!\n", get_name(search_list(list, key)));
 
-        if (test_data->num == 2)
-            printf("Found %s!\n", test_data->name);
-    }
 
-    lnode = head_list(list, true);
+    list_node_t *lnode = head_list(list, true);
     delete_node(list, lnode);
 
     delete_list(list);