1 files changed, 156 insertions, 0 deletions
diff --git a/src/vppinfra/dlist.h b/src/vppinfra/dlist.h
new file mode 100644
index 00000000000..7d09b2bbc7e
--- /dev/null
+++ b/src/vppinfra/dlist.h
@@ -0,0 +1,156 @@
+/*
+ * Copyright (c) 2016 Cisco and/or its affiliates.
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ *
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+*/
+
+#ifndef included_dlist_h
+#define included_dlist_h
+
+#include <stdarg.h>
+#include <vppinfra/clib.h>
+#include <vppinfra/vec.h>
+#include <vppinfra/pool.h>
+#include <vppinfra/error.h>
+#include <vppinfra/format.h>
+#include <vppinfra/cache.h>
+
+typedef struct
+{
+  u32 next;
+  u32 prev;
+  u32 value;
+} dlist_elt_t;
+
+static inline void
+clib_dlist_init (dlist_elt_t * pool, u32 index)
+{
+  dlist_elt_t *head = pool_elt_at_index (pool, index);
+  memset (head, 0xFF, sizeof (*head));
+}
+
+static inline void
+clib_dlist_addtail (dlist_elt_t * pool, u32 head_index, u32 new_index)
+{
+  dlist_elt_t *head = pool_elt_at_index (pool, head_index);
+  u32 old_last_index;
+  dlist_elt_t *old_last;
+  dlist_elt_t *new;
+
+  ASSERT (head->value == ~0);
+
+  new = pool_elt_at_index (pool, new_index);
+
+  if (PREDICT_FALSE (head->next == ~0))
+    {
+      head->next = head->prev = new_index;
+      new->next = new->prev = head_index;
+      return;
+    }
+
+  old_last_index = head->prev;
+  old_last = pool_elt_at_index (pool, old_last_index);
+
+  new->next = old_last->next;
+  new->prev = old_last_index;
+  old_last->next = new_index;
+  head->prev = new_index;
+}
+
+static inline void
+clib_dlist_addhead (dlist_elt_t * pool, u32 head_index, u32 new_index)
+{
+  dlist_elt_t *head = pool_elt_at_index (pool, head_index);
+  dlist_elt_t *old_first;
+  u32 old_first_index;
+  dlist_elt_t *new;
+
+  ASSERT (head->value == ~0);
+
+  new = pool_elt_at_index (pool, new_index);
+
+  if (PREDICT_FALSE (head->next == ~0))
+    {
+      head->next = head->prev = new_index;
+      new->next = new->prev = head_index;
+      return;
+    }
+
+  old_first_index = head->next;
+  old_first = pool_elt_at_index (pool, old_first_index);
+
+  new->next = old_first_index;
+  new->prev = old_first->prev;
+  old_first->prev = new_index;
+  head->next = new_index;
+}
+
+static inline void
+clib_dlist_remove (dlist_elt_t * pool, u32 index)
+{
+  dlist_elt_t *elt = pool_elt_at_index (pool, index);
+  dlist_elt_t *next_elt, *prev_elt;
+
+  /* listhead, not so much */
+  ASSERT (elt->value != ~0);
+
+  next_elt = pool_elt_at_index (pool, elt->next);
+  prev_elt = pool_elt_at_index (pool, elt->prev);
+
+  next_elt->prev = elt->prev;
+  prev_elt->next = elt->next;
+
+  elt->prev = elt->next = ~0;
+}
+
+static inline u32
+clib_dlist_remove_head (dlist_elt_t * pool, u32 head_index)
+{
+  dlist_elt_t *head = pool_elt_at_index (pool, head_index);
+  u32 rv;
+
+  ASSERT (head->value == ~0);
+
+  if (head->next == ~0)
+    return ~0;
+
+  rv = head->next;
+  clib_dlist_remove (pool, rv);
+  return rv;
+}
+
+static inline u32
+clib_dlist_remove_tail (dlist_elt_t * pool, u32 head_index)
+{
+  dlist_elt_t *head = pool_elt_at_index (pool, head_index);
+  u32 rv;
+
+  ASSERT (head->value == ~0);
+
+  if (head->prev == ~0)
+    return ~0;
+
+  rv = head->prev;
+  clib_dlist_remove (pool, rv);
+  return rv;
+}
+
+#endif /* included_dlist_h */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */