Implemented deletion of entries (and dbl link lists)

2 files changed, 33 insertions, 2 deletions

diff --git a/tasklst.c b/tasklst.c
index ab30f31..b64fa2d 100644
--- a/tasklst.c
+++ b/tasklst.c
@@ -108,7 +108,6 @@ task_lst_add_task(TaskLst *list, int status, const char *str)
 		return -1;
 
 	newtask->status = status;
-	newtask->next = NULL;
 	strncpy(newtask->tdesc, str, TASK_LST_DESC_MAX_SIZE);
 
 	last = task_lst_get_last_task(*list);
@@ -117,12 +116,42 @@ task_lst_add_task(TaskLst *list, int status, const char *str)
 	else
 		last->next = newtask;
 
+	newtask->prev = last; /* Also if last == NULL */
+	newtask->next = NULL;
+
 	return 0;
 } 
 
+int
+task_lst_del_task(TaskLst *list, int i)
+{
+	Task *del, *prev, *next;
+
+	if ((i > task_lst_get_size(*list)) || (i < 0))
+		return -1;
+
+	if ((del = task_lst_get_task(*list, i)) == NULL)
+		return -1;
+
+	prev = del->prev;
+	next = del->next;
+
+	if (prev != NULL)
+		prev->next = next;
+
+	if (next != NULL)
+		next->prev = prev;
+
+	free(del);
+
+	return 0;
+}
+
 Task *
-task_lst_get_task(TaskLst list, int i)
+task_lst_get_task(TaskLst list, int i) /* TODO: mv above task_lst_add_task() */
 {
+	/* TODO: Maybe binary search? */
+
 	Task *ptr;
 	
 	for (ptr = list.first; i > 0; ptr = ptr->next) {
diff --git a/tasklst.h b/tasklst.h
index ee3b56b..bb1d94d 100644
--- a/tasklst.h
+++ b/tasklst.h
@@ -10,6 +10,7 @@ enum {
 typedef struct TASK_ Task;
 struct TASK_ {
 	int status;
+	Task *prev;
 	Task *next;
 	char tdesc[TASK_LST_DESC_MAX_SIZE];
 };
@@ -28,6 +29,7 @@ int task_lst_count_todo(TaskLst list);
 int task_lst_count_done(TaskLst list);
 Task *task_lst_get_task(TaskLst list, int i);
 int task_lst_add_task(TaskLst *list, int status, const char *str);
+int task_lst_del_task(TaskLst *list, int i);
 int task_lst_read_from_file(TaskLst *list, FILE *fp);
 void task_lst_write_to_file(FILE *fp, TaskLst list);