lib: Revise implementation of list

Adds LGPL license to the ouroboros lists.

1 files changed, 38 insertions, 90 deletions

diff --git a/src/lib/list.c b/src/lib/list.c
index 0f3493e3..6bdb3461 100644
--- a/src/lib/list.c
+++ b/src/lib/list.c
@@ -3,122 +3,70 @@
  *
  * Simple doubly linked list implementation.
  *
- * Some of the internal functions ("__xxx") are useful when
- * manipulating whole lists rather than single entries, as
- * sometimes we already know the next/prev entries and we can
- * generate better code by using them directly rather than
- * using the generic single-entry routines.
+ *    Sander Vrijders    <[email protected]>
+ *    Dimitri Staessense <[email protected]>
  *
- * This file is from the Linux Kernel (include/linux/list.h)
- * and modified by simply removing hardware prefetching of list items.
- * Here by copyright, credits attributed to wherever they belong.
- * Kulesh Shanmugasundaram (kulesh [squiggly] isis.poly.edu)
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * version 2.1 as published by the Free Software Foundation.
  *
- *    Sander Vrijders <[email protected]>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
+ * This library 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.
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301 USA
  */
 
 #include <ouroboros/list.h>
 
-static void __list_add(struct list_head * new,
-                       struct list_head * prev,
-                       struct list_head * next)
-{
-        next->prev = new;
-        new->next = next;
-        new->prev = prev;
-        prev->next = new;
-}
-
-void list_add(struct list_head * new,
-              struct list_head * head)
-{
-        __list_add(new, head, head->next);
-}
-
-void list_add_tail(struct list_head * new,
-                   struct list_head * head)
-{
-        __list_add(new, head->prev, head);
-}
-
-static void __list_del(struct list_head * prev,
-                       struct list_head * next)
-{
-        next->prev = prev;
-        prev->next = next;
-}
+#include <stddef.h>
 
-void list_del(struct list_head * entry)
+void list_head_init(struct list_head * h)
 {
-        __list_del(entry->prev, entry->next);
-        entry->next = (void *) 0;
-        entry->prev = (void *) 0;
+        h->nxt = h;
+        h->prv = h;
 }
 
-void list_del_init(struct list_head * entry)
+static void add_list(struct list_head * n,
+                     struct list_head * prv,
+                     struct list_head * nxt)
 {
-        __list_del(entry->prev, entry->next);
-        INIT_LIST_HEAD(entry);
+        nxt->prv = n;
+        n->nxt = nxt;
+        n->prv = prv;
+        prv->nxt = n;
 }
 
-void list_move(struct list_head * list,
-               struct list_head * head)
+static void del_list(struct list_head * prv,
+                     struct list_head * nxt)
 {
-        __list_del(list->prev, list->next);
-        list_add(list, head);
+        nxt->prv = prv;
+        prv->nxt = nxt;
 }
 
-void list_move_tail(struct list_head * list,
-                    struct list_head * head)
+void list_add(struct list_head * n,
+              struct list_head * h)
 {
-        __list_del(list->prev, list->next);
-        list_add_tail(list, head);
+        add_list(n, h, h->nxt);
 }
 
-int list_empty(struct list_head * head)
+void list_add_tail(struct list_head * n,
+                   struct list_head * h)
 {
-        return head->next == head;
-}
-
-static void __list_splice(struct list_head *list,
-                          struct list_head *head)
-{
-        struct list_head *first = list->next;
-        struct list_head *last = list->prev;
-        struct list_head *at = head->next;
-
-        first->prev = head;
-        head->next = first;
-
-        last->next = at;
-        at->prev = last;
+        add_list(n, h->prv, h);
 }
 
-void list_splice(struct list_head * list,
-                 struct list_head * head)
+void list_del(struct list_head * e)
 {
-        if (!list_empty(list))
-                __list_splice(list, head);
+        del_list(e->prv, e->nxt);
+        e->nxt = e->prv = NULL;
 }
 
-void list_splice_init(struct list_head * list,
-                      struct list_head * head)
+bool list_is_empty(struct list_head * h)
 {
-        if (!list_empty(list)) {
-                __list_splice(list, head);
-                INIT_LIST_HEAD(list);
-        }
+        return h->nxt == h;
 }