/*
 * callback.h -- C++ callback mechanism
 * Copyright (C) 2003-2018 Marc Lehmann <pcg@goof.com>
 *
 * This file is part of GVPE.
 *
 * 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 * Additional permission under GNU GPL version 3 section 7
 *
 * If you modify this Program, or any covered work, by linking or
 * combining it with the OpenSSL project's OpenSSL library (or a modified
 * version of that library), containing parts covered by the terms of the
 * OpenSSL or SSLeay licenses, the licensors of this Program grant you
 * additional permission to convey the resulting work.  Corresponding
 * Source for a non-source form of such a combination shall include the
 * source code for the parts of OpenSSL used as well as that of the
 * covered work.
*/

#ifndef CALLBACK_H__
#define CALLBACK_H__

#define CALLBACK_H_VERSION 4

template<typename signature>
struct callback;

template<class R, class ...Args>
struct callback<R (Args...)>
{
  typedef R (*ptr_type)(void *self, Args...);

  template<class K, R (K::*method)(Args...)>
  void set (K *object)
  {
    self = object;
    func = thunk<K, method>;
  }

  R call (Args... args) const
  {
    return func (self, args...);
  }

  R operator ()(Args... args) const
  {
    return call (args...);
  }

private:

  void *self;
  ptr_type func;

  template<class klass, R (klass::*method)(Args...)>
  static R thunk (void *self, Args... args)
  {
    klass *obj = static_cast<klass *>(self);
    return (obj->*method) (args...);
  }
};

#endif