Reorganized to contain list abstraction

src/util/list.c

@@ -6,7 +6,7 @@
  Description:  Generic list
                https://gist.github.com/pseudomuto/6334796#file-list-c
                Accessed: April 9, 2019
- Authors:      David Muto, Modified by Michael E. Tryby
+ Authors:      David Muto, Michael Tryby
  Copyright:    see AUTHORS
  License:      see LICENSE
  Last Updated: 04/09/2019
@@ -27,6 +27,21 @@
 #include "list.h"
 
 
+typedef struct list_node_s {
+    void *data;
+    struct list_node_s *next;
+} list_node_t;
+
+
+typedef struct list_s {
+    int logicalLength;
+    size_t elementSize;
+    list_node_t *head;
+    list_node_t *tail;
+    freeFunction freeFn;
+} list_t;
+
+
 list_t *create_list(size_t elementSize, freeFunction freeFn)
 {
     list_t *list;
@@ -59,7 +74,7 @@ void delete_list(list_t *list)
 
 void prepend_list(list_t *list, void *element)
 {
-	list_node_t *node = malloc(sizeof(list_node_t));
+    list_node_t *node = malloc(sizeof(list_node_t));
     node->data = malloc(list->elementSize);
     memcpy(node->data, element, list->elementSize);
 
@@ -99,7 +114,7 @@ void for_each_list(list_t *list, listIterator iterator)
     list_node_t *node = list->head;
     bool result = true;
     while(node != NULL && result) {
-        result = iterator(node->data);
+        result = iterator(node);
         node = node->next;
     }
 }
@@ -127,7 +142,7 @@ void *head_list(list_t *list, bool removeFromList)
     }
     // Now element points to data formerly pointed to by node. Caller
     // is responsible for freeing both pointer to data and data.
-	return element;
+    return element;
 }
 
 void *tail_list(list_t *list)
@@ -144,10 +159,36 @@ void *tail_list(list_t *list)
 
     // Pointer to element data gets returned. Caller is responsible
     // for freeing pointer to data.
-	return element;
+    return element;
 }
 
 int size_list(list_t *list)
 {
     return list->logicalLength;
 }
+
+void *get_data(list_node_t *lnode)
+{
+    return lnode->data;
+}
+
+
+//
+// Iterator operations
+// http://www.cs.yale.edu/homes/aspnes/pinewiki/C(2f)Iterators.html
+// Accessed on April 11, 2019
+//
+list_node_t *first_list(list_t *list)
+{
+    return list->head;
+}
+
+bool done_list(list_node_t *lnode)
+{
+    return lnode != NULL;
+}
+
+list_node_t *next_list(list_node_t *lnode)
+{
+    return lnode->next;
+}

src/util/list.h

@@ -6,7 +6,7 @@
  Description:  Generic list
                https://gist.github.com/pseudomuto/6334796#file-list-h
                Accessed: April 9, 2019
- Authors:      David Muto, Modified by Michael E. Tryby
+ Authors:      David Muto, Michael Tryby
  Copyright:    see AUTHORS
  License:      see LICENSE
  Last Updated: 04/09/2019
@@ -23,24 +23,13 @@
 extern "C" {
 #endif
 
-// a common function used to free malloc'd objects
+
+// Forward declarations
+typedef struct list_node_s list_node_t;
+typedef struct list_s list_t;
+
 typedef void(*freeFunction)(void *);
-typedef bool(*listIterator)(void *);
-
-
-typedef struct list_node_s {
-    void *data;
-    struct list_node_s *next;
-} list_node_t;
-
-
-typedef struct {
-    int logicalLength;
-    size_t elementSize;
-    list_node_t *head;
-    list_node_t *tail;
-    freeFunction freeFn;
-} list_t;
+typedef bool(*listIterator)(list_node_t *);
 
 
 /**
@@ -70,6 +59,12 @@ void append_list(list_t *list, void *element);
 */
 int size_list(list_t *list);
 
+/**
+@brief Returns pointer to list node's data.
+*/
+void *get_data(list_node_t *lnode);
+
+
 /**
 @brief Calls the supplied iterator function with the data element of each
 node (iterates over the list).
@@ -87,6 +82,22 @@ void *head_list(list_t *list, bool removeFromList);
 void *tail_list(list_t *list);
 
 
+/**
+@brief Returns list head node.
+*/
+list_node_t *first_list(list_t *list);
+
+/**
+@brief Returns true if end of list false otherwise.
+*/
+bool done_list(list_node_t *lnode);
+
+/**
+@brief Returns next node in the list.
+*/
+list_node_t *next_list(list_node_t *lnode);
+
+
 #if defined(__cplusplus)
 }
 #endif

tests/util/test_list.cpp

@@ -28,24 +28,16 @@ boost::test_tools::predicate_result check_string(std::string test, std::string r
         return false;
 }
 
+int *get_int_data(list_node_t *lnode) {
+    return (int *)get_data(lnode);
+}
 
-bool iterate_int(void *data)
+bool iterate_int(list_node_t *lnode)
 {
-    printf("Found value: %d\n", *(int *)data);
+    printf("Found value: %d\n", *get_int_data(lnode));
     return true;
 }
 
-bool iterate_string(void *data)
-{
-    char *string = *(char **)data;
-    printf("Found string value: %s\n", string);
-    return true;
-}
-
-void free_string(void *data)
-{
-    free(*(char **)data);
-}
 
 BOOST_AUTO_TEST_SUITE(test_list)
 
@@ -76,6 +68,23 @@ BOOST_AUTO_TEST_CASE(test_int_list){
     delete_list(list);
 }
 
+
+inline char *get_string_data(list_node_t *lnode)
+{
+    return *(char **)get_data(lnode);
+}
+
+bool iterate_string(list_node_t *lnode)
+{
+    printf("Found string value: %s\n", get_string_data(lnode));
+    return true;
+}
+
+void free_string(void *data)
+{
+    free(*(char **)data);
+}
+
 struct FixtureStrings{
     FixtureStrings() {
         list = NULL;
@@ -134,7 +143,7 @@ typedef struct test_data_s {
     char   *name;
 } test_data_t;
 
-test_data_t *create_test_data(int number, char *name){
+test_data_t *create_test_data(int number, const char *name){
 
     test_data_t *data = (test_data_t *)malloc(sizeof(test_data_t));
     data->num = number;
@@ -156,9 +165,14 @@ void delete_test_data(void *data) {
 	free(test_data);
 }
 
-bool iterate_test_data(void *data)
+inline test_data_t *get_test_data(list_node_t *lnode)
 {
-    test_data_t *test_data = *(test_data_t **)data;
+    return *(test_data_t **)get_data(lnode);
+}
+
+bool iterate_test_data(list_node_t *lnode)
+{
+    test_data_t *test_data = get_test_data(lnode);
 
     printf("Found number: %i name: %s\n", test_data->num, test_data->name);
     return true;
@@ -186,10 +200,10 @@ BOOST_AUTO_TEST_CASE(test_struct_list){
 
     //for_each_list(list, iterate_test_data);
 
-    // Expose list abstraction and loop over it
     list_node_t *lnode;
-    for (lnode = list->head; lnode != NULL; lnode = lnode->next) {
-        test_data_t *test_data = *(test_data_t **)lnode->data;
+    // Iterate over list while maintaining containment of abstraction
+    for (lnode = first_list(list); done_list(lnode); lnode = next_list(lnode)) {
+        test_data_t *test_data = get_test_data(lnode);
         printf("Found number: %i name: %s\n", test_data->num, test_data->name);
     }