1 files changed, 93 insertions, 0 deletions
diff --git a/src/list.c b/src/list.c
new file mode 100644
index 0000000..9fa2b3f
--- /dev/null
+++ b/src/list.c
@@ -0,0 +1,93 @@
+/*
+ *  Copyright (c) 2002-2003 Erik Fears
+ *  Copyright (c) 2014-2018 ircd-hybrid development team
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301
+ *  USA
+ */
+
+/*! \file list.c
+ * \brief Maintains doubly-linked lists.
+ * \version $Id$
+ */
+
+#include <stdlib.h>
+#include <assert.h>
+
+#include "memory.h"
+#include "list.h"
+
+
+node_t *
+node_create(void)
+{
+  node_t *node = xcalloc(sizeof *node);
+  return node;
+}
+
+void
+node_free(node_t *node)
+{
+  xfree(node);
+}
+
+node_t *
+list_add(void *data, node_t *node, list_t *list)
+{
+  node->data = data;
+  node->prev = NULL;
+  node->next = list->head;
+
+  /* Assumption: If list->tail != NULL, list->head != NULL */
+  if (list->head)
+    list->head->prev = node;
+  else if (list->tail == NULL)
+    list->tail = node;
+
+  list->head = node;
+  list->elements++;
+
+  return node;
+}
+
+node_t *
+list_remove(node_t *node, list_t *list)
+{
+  /* Assumption: If node->next == NULL, then list->tail == node
+   *      and:   If node->prev == NULL, then list->head == node
+   */
+  if (node->next)
+    node->next->prev = node->prev;
+  else
+  {
+    assert(list->tail == node);
+    list->tail = node->prev;
+  }
+
+  if (node->prev)
+    node->prev->next = node->next;
+  else
+  {
+    assert(list->head == node);
+    list->head = node->next;
+  }
+
+  /* Set this to NULL does matter */
+  node->next = NULL;
+  node->prev = NULL;
+  list->elements--;
+
+  return node;
+}