1 files changed, 158 insertions, 0 deletions
diff --git a/lib/list.c b/lib/list.c
new file mode 100644
index 000000000..087a5f445
--- /dev/null
+++ b/lib/list.c
@@ -0,0 +1,158 @@
+/*
+ * Copyright (c) 2008, 2009 Nicira Networks.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+#include <config.h>
+#include "list.h"
+#include <assert.h>
+
+/* Initializes 'list' as an empty list. */
+void
+list_init(struct list *list)
+{
+    list->next = list->prev = list;
+}
+
+/* Inserts 'elem' just before 'before'. */
+void
+list_insert(struct list *before, struct list *elem)
+{
+  elem->prev = before->prev;
+  elem->next = before;
+  before->prev->next = elem;
+  before->prev = elem;
+}
+
+/* Removes elements 'first' though 'last' (exclusive) from their current list,
+   then inserts them just before 'before'. */
+void
+list_splice(struct list *before, struct list *first, struct list *last)
+{
+  if (first == last)
+    return;
+  last = last->prev;
+
+  /* Cleanly remove 'first'...'last' from its current list. */
+  first->prev->next = last->next;
+  last->next->prev = first->prev;
+
+  /* Splice 'first'...'last' into new list. */
+  first->prev = before->prev;
+  last->next = before;
+  before->prev->next = first;
+  before->prev = last;
+}
+
+/* Inserts 'elem' at the beginning of 'list', so that it becomes the front in
+   'list'. */
+void
+list_push_front(struct list *list, struct list *elem)
+{
+  list_insert(list->next, elem);
+}
+
+/* Inserts 'elem' at the end of 'list', so that it becomes the back in
+ * 'list'. */
+void
+list_push_back(struct list *list, struct list *elem)
+{
+  list_insert(list, elem);
+}
+
+/* Puts 'elem' in the position currently occupied by 'position'.
+ * Afterward, 'position' is not part of a list. */
+void
+list_replace(struct list *element, const struct list *position)
+{
+    element->next = position->next;
+    element->next->prev = element;
+    element->prev = position->prev;
+    element->prev->next = element;
+}
+
+/* Adjusts pointers around 'list' to compensate for 'list' having been moved
+ * around in memory (e.g. as a consequence of realloc()). */
+void
+list_moved(struct list *list)
+{
+    list->prev->next = list->next->prev = list;
+}
+
+/* Removes 'elem' from its list and returns the element that followed it.
+   Undefined behavior if 'elem' is not in a list. */
+struct list *
+list_remove(struct list *elem)
+{
+  elem->prev->next = elem->next;
+  elem->next->prev = elem->prev;
+  return elem->next;
+}
+
+/* Removes the front element from 'list' and returns it.  Undefined behavior if
+   'list' is empty before removal. */
+struct list *
+list_pop_front(struct list *list)
+{
+  struct list *front = list->next;
+  list_remove(front);
+  return front;
+}
+
+/* Removes the back element from 'list' and returns it.
+   Undefined behavior if 'list' is empty before removal. */
+struct list *
+list_pop_back(struct list *list)
+{
+  struct list *back = list->prev;
+  list_remove(back);
+  return back;
+}
+
+/* Returns the front element in 'list'.
+   Undefined behavior if 'list' is empty. */
+struct list *
+list_front(struct list *list)
+{
+  assert(!list_is_empty(list));
+  return list->next;
+}
+
+/* Returns the back element in 'list'.
+   Undefined behavior if 'list' is empty. */
+struct list *
+list_back(struct list *list)
+{
+  assert(!list_is_empty(list));
+  return list->prev;
+}
+
+/* Returns the number of elements in 'list'.
+   Runs in O(n) in the number of elements. */
+size_t
+list_size(const struct list *list)
+{
+  const struct list *e;
+  size_t cnt = 0;
+
+  for (e = list->next; e != list; e = e->next)
+    cnt++;
+  return cnt;
+}
+
+/* Returns true if 'list' is empty, false otherwise. */
+bool
+list_is_empty(const struct list *list)
+{
+  return list->next == list;
+}