llist: Add a C++ wrapper for linux_list

This commit adds the LListHead class which is a wrapper around the
linuxlist. It adds an additional member to refer to the container,
since the container_of macro doesn't work properly with C++ classes.
All functions and macros from linuxlist.h are support except for the
entry macros (e.g. llist_entry, llist_for_each_entry, ...). To access
the container (entry), an entry() method is provided instead:

  llist_for_each(pos, &elems) {
      pos->entry()->do_something();
  }

Sponsored-by: On-Waves ehf

1 files changed, 133 insertions, 0 deletions

diff --git a/src/cxx_linuxlist.h b/src/cxx_linuxlist.h
new file mode 100644
index 0000000..d9b28c4
--- /dev/null
+++ b/src/cxx_linuxlist.h
@@ -0,0 +1,133 @@
+/* cxx_linuxlist.h
+ *
+ * Copyright (C) 2015 by Sysmocom s.f.m.c. GmbH
+ * Author: Jacob Erlbeck <jerlbeck@sysmocom.de>
+ *
+ * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+ */
+
+#pragma once
+
+extern "C" {
+	#include <osmocom/core/linuxlist.h>
+}
+
+template <typename T>
+struct LListHead {
+	typedef T entry_t;
+
+	/* This must match the declaration of struct llist_head */
+	LListHead<T> *next;
+	LListHead<T> *prev;
+
+	LListHead() : m_back(0) { INIT_LLIST_HEAD(this); }
+	LListHead(T* entry) : m_back(entry) {
+		next = (LListHead<T> *)LLIST_POISON1;
+		prev = (LListHead<T> *)LLIST_POISON2;
+	}
+
+	T *entry() {return m_back;}
+	const T *entry() const {return m_back;}
+
+	llist_head &llist() {
+		return *static_cast<llist_head *>(static_cast<void *>(this));
+	}
+	const llist_head &llist() const {
+		return *static_cast<llist_head *>(static_cast<void *>(this));
+	}
+
+private:
+	T *const m_back;
+};
+
+/* Define a family of casting functions */
+template <typename T>
+llist_head &llist(LListHead<T> &l)
+{
+	return l->llist();
+}
+
+template <typename T>
+const llist_head &llist(const LListHead<T> &l)
+{
+	return l->llist();
+}
+
+template <typename T>
+llist_head *llptr(LListHead<T> *l)
+{
+	return &(l->llist());
+}
+
+template <typename T>
+const llist_head *llptr(const LListHead<T> *l)
+{
+	return &(l->llist());
+}
+
+/* Define type-safe wrapper for the existing linux_list.h functions */
+template <typename T>
+inline void llist_add(LListHead<T> *new_, LListHead<T> *head)
+{
+	llist_add(llptr(new_), llptr(head));
+}
+
+template <typename T>
+inline void llist_add_tail(LListHead<T> *new_, LListHead<T> *head)
+{
+	llist_add_tail(llptr(new_), llptr(head));
+}
+
+template <typename T>
+inline void llist_del(LListHead<T> *entry)
+{
+	llist_del(llptr(entry));
+}
+
+template <typename T>
+inline void llist_del_init(LListHead<T> *entry)
+{
+	llist_del_init(llptr(entry));
+}
+
+template <typename T>
+inline void llist_move(LListHead<T> *list, LListHead<T> *head)
+{
+	llist_move(llptr(list), llptr(head));
+}
+
+template <typename T>
+inline void llist_move_tail(LListHead<T> *list, LListHead<T> *head)
+{
+	llist_move_tail(llptr(list), llptr(head));
+}
+
+template <typename T>
+inline int llist_empty(const LListHead<T> *head)
+{
+	return llist_empty(llptr(head));
+}
+
+template <typename T>
+inline void llist_splice(LListHead<T> *list, LListHead<T> *head)
+{
+	llist_splice(llptr(list), llptr(head));
+}
+
+template <typename T>
+inline void llist_splice_init(LListHead<T> *list, LListHead<T> *head)
+{
+	llist_splice_init(llptr(list), llptr(head));
+}