vppinfra: add doubly linked list

Type: feature

Change-Id: I21511c1abea703da67f1a491e73342496275c498
Signed-off-by: Florin Coras <fcoras@cisco.com>

1 files changed, 254 insertions, 0 deletions

diff --git a/src/vppinfra/llist.h b/src/vppinfra/llist.h
new file mode 100644
index 00000000000..1648021681f
--- /dev/null
+++ b/src/vppinfra/llist.h
@@ -0,0 +1,254 @@
+/*
+ * Copyright (c) 2019 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.
+ *
+ * @file
+ * @brief Circular doubly linked list with head sentinel.
+ * List entries are allocated out of a "supporting" pool and all pool entries
+ * must contain a list anchor struct for each list they pertain to.
+ */
+
+#ifndef SRC_VPPINFRA_CLIB_LLIST_H_
+#define SRC_VPPINFRA_CLIB_LLIST_H_
+
+#include <vppinfra/types.h>
+#include <vppinfra/pool.h>
+
+typedef u32 clib_llist_index_t;
+
+typedef struct clib_llist_anchor
+{
+  clib_llist_index_t prev;
+  clib_llist_index_t next;
+} clib_llist_anchor_t;
+
+#define CLIB_LLIST_INVALID_INDEX ((u32)~0)
+
+/**
+ * Local variable naming macro.
+ */
+#define _ll_var(v) _llist_##v
+/**
+ * Local macros to grab llist anchor next and prev from pool entry
+ */
+#define _lnext(E,name) ((E)->name).next
+#define _lprev(E,name) ((E)->name).prev
+/**
+ * Get list entry index
+ *
+ * @param LP	linked list pool
+ * @param E	pool entry
+ * @return	pool entry index
+ */
+#define clib_llist_entry_index(LP,E) ((E) - (LP))
+/**
+ * Get next pool entry
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param E	pool entry
+ * @return	next pool entry
+ */
+#define clib_llist_next(LP,name,E) pool_elt_at_index((LP),_lnext((E),name))
+/**
+ * Get previous pool entry
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param E	pool entry
+ * @return	previous pool entry
+ */
+#define clib_llist_prev(LP,name,E) pool_elt_at_index((LP),_lprev((E),name))
+/**
+ * Initialize element in llist for entry
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param E	entry whose ll anchor is to be initialized
+ */
+#define clib_llist_anchor_init(LP,name,E)				\
+do {									\
+  _lprev ((E),name) = clib_llist_entry_index ((LP), (E));		\
+  _lnext ((E),name) = _lprev ((E),name);				\
+} while (0)
+/**
+ * Initialize llist head
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ */
+#define clib_llist_make_head(LP,name)					\
+({									\
+  typeof (LP) _ll_var (head);						\
+  pool_get_zero ((LP), _ll_var (head));					\
+  clib_llist_anchor_init ((LP),name,_ll_var (head));			\
+  clib_llist_entry_index ((LP), _ll_var (head));			\
+})
+/**
+ * Check is list is empty
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param H	list head
+ * @return	1 if sentinel is the only node part of the list, 0 otherwise
+ */
+#define clib_llist_is_empty(LP,name,H) ((H) == clib_llist_next((LP),name,(H)))
+/**
+ * Insert entry between previous and next
+ *
+ * Internal use.
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param E	new entry
+ * @param P	previous in list
+ * @param N	next in list
+ */
+#define _llist_insert(LP,name,E,P,N)					\
+do {									\
+  _lprev (E,name) = _lprev(N,name);					\
+  _lnext (E,name) = _lnext(P,name);					\
+  _lprev ((N),name) = clib_llist_entry_index ((LP),(E));		\
+  _lnext ((P),name) = clib_llist_entry_index ((LP),(E));		\
+} while (0)
+/**
+ * Insert entry after previous
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param E	new entry
+ * @param P	previous in list
+ */
+#define clib_llist_insert(LP,name,E,P) 					\
+do {									\
+  typeof (LP) _ll_var (N) = clib_llist_next (LP,name,P);		\
+  _llist_insert ((LP),name,(E),(P), _ll_var (N));			\
+} while (0)
+
+/**
+ * Add entry after head
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param E	new entry
+ * @param H	list head
+ */
+#define clib_llist_add(LP,name,E,H) clib_llist_insert ((LP),name,(E),(H))
+/**
+ * Add entry after tail
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param E	new entry
+ * @param H	list head
+ */
+#define clib_llist_add_tail(LP,name,E,H)				\
+do {									\
+  typeof (LP) _ll_var (P) = clib_llist_prev ((LP),name,(H));		\
+  _llist_insert ((LP),name,(E),_ll_var (P),(H));			\
+} while (0)
+/**
+ * Remove entry from list
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param E	entry to be removed
+ */
+#define clib_llist_remove(LP,name,E)					\
+do {									\
+  ASSERT ((E) != clib_llist_next (LP,name,E));/* don't remove sentinel */\
+  ASSERT (_lnext (E,name) != CLIB_LLIST_INVALID_INDEX);			\
+  ASSERT (_lprev (E,name) != CLIB_LLIST_INVALID_INDEX);			\
+  typeof (LP) _ll_var (P) = clib_llist_prev ((LP),name,E);		\
+  typeof (LP) _ll_var (N) = clib_llist_next ((LP),name,E);		\
+  _lnext (_ll_var (P),name) = _lnext (E,name);				\
+  _lprev (_ll_var (N),name) = _lprev (E,name);				\
+  _lnext (E,name) = _lprev (E,name) = CLIB_LLIST_INVALID_INDEX;		\
+}while (0)
+
+/**
+ * Splice two lists at a given position
+ *
+ * List spliced into destination list is left with 0 entries, i.e., head
+ * is made to point to itself.
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param P	position in destination where source list is spliced
+ * @param H	head of source list that will be spliced into destination
+ */
+#define clib_llist_splice(LP,name,P,H)					\
+do {									\
+  typeof (LP) _ll_var (fe) = clib_llist_next (LP,name,H);		\
+  if (_ll_var (fe) != (H))						\
+    {									\
+      typeof (LP) _ll_var (le) = clib_llist_prev (LP,name,H);		\
+      typeof (LP) _ll_var (ne) = clib_llist_next (LP,name,P);		\
+      _lprev (_ll_var (fe),name) = clib_llist_entry_index(LP,P);	\
+      _lnext (_ll_var (le),name) = clib_llist_entry_index(LP,_ll_var (ne));\
+      _lnext (P,name) = clib_llist_entry_index (LP,_ll_var (fe));	\
+      _lprev (_ll_var (ne),name) = clib_llist_entry_index(LP,_ll_var (le));\
+      _lnext (H,name) = clib_llist_entry_index(LP,H);			\
+      _lprev (H,name) = _lnext (H,name);				\
+    }									\
+} while (0)
+/**
+ * Walk list starting at head
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param H	head entry
+ * @param E	entry iterator
+ * @param body	code to be executed
+ */
+#define clib_llist_foreach(LP,name,H,E,body)				\
+do {									\
+  typeof (LP) _ll_var (n);						\
+  (E) = clib_llist_next (LP,name,H);					\
+  while (E != H)							\
+    { 									\
+      _ll_var (n) = clib_llist_next (LP,name,E);			\
+      do { body; } while (0);						\
+      (E) = _ll_var (n);						\
+    }									\
+} while (0)
+/**
+ * Walk list starting at head in reverse order
+ *
+ * @param LP	linked list pool
+ * @param name	list anchor name
+ * @param H	head entry
+ * @param E	entry iterator
+ * @param body	code to be executed
+ */
+#define clib_llist_foreach_reverse(LP,name,H,E,body)			\
+do {									\
+  typeof (LP) _ll_var (p);						\
+  (E) = clib_llist_prev (LP,name,H);					\
+  while (E != H)							\
+    { 									\
+      _ll_var (p) = clib_llist_prev (LP,name,E);			\
+      do { body; } while (0);						\
+      (E) = _ll_var (p);						\
+    }									\
+} while (0)
+
+#endif /* SRC_VPPINFRA_CLIB_LLIST_H_ */
+
+/*
+ * fd.io coding-style-patch-verification: ON
+ *
+ * Local Variables:
+ * eval: (c-set-style "gnu")
+ * End:
+ */