ipc_ret_array

// vi:set ft=cpp: -*- Mode: C++ -*-
/*
 * (c) 2014 Alexander Warg <alexander.warg@kernkonzept.com>
 *
 * This file is part of TUD:OS and distributed under the terms of the
 * GNU General Public License 2.
 * Please see the COPYING-GPL-2 file for details.
 *
 * As a special exception, you may use this file as part of a free software
 * library without restriction.  Specifically, if other files instantiate
 * templates or use macros or inline functions from this file, or you compile
 * this file and link it with other files to produce an executable, this
 * file does not by itself cause the resulting executable to be covered by
 * the GNU General Public License.  This exception does not however
 * invalidate any other reasons why the executable file might be covered by
 * the GNU General Public License.
 */
#pragma once
 
#include "types"
#include "ipc_basics"
 
namespace L4 { namespace Ipc L4_EXPORT {
 
// ---------------------------------------------------------------
template<typename T> struct L4_EXPORT Ret_array
{
  typedef T const **ptr_type;
 
  T *value = nullptr;
  unsigned max = 0;
  Ret_array() {}
  Ret_array(T *v, unsigned max) : value(v), max(max) {}
};
 
namespace Msg {
 
template<typename A> struct Elem< Ret_array<A> >
{
  enum { Is_optional = false };
  typedef Ret_array<A> type;
  typedef typename type::ptr_type arg_type;
  typedef type svr_type;
  typedef type svr_arg_type;
};
 
template<typename A>
struct Is_valid_rpc_type<Ret_array<A> *> : L4::Types::False {};
template<typename A>
struct Is_valid_rpc_type<Ret_array<A> &> : L4::Types::False {};
template<typename A>
struct Is_valid_rpc_type<Ret_array<A> const &> : L4::Types::False {};
template<typename A>
struct Is_valid_rpc_type<Ret_array<A> const *> : L4::Types::False {};
 
template<typename A> struct Class< Ret_array<A> > : Class<A>::type {};
template<typename A> struct Direction< Ret_array<A> > : Dir_out {};
 
template<typename A, typename CLASS>
struct Clnt_val_ops<A const *, Dir_out, CLASS> : Clnt_noops<A const *>
{
  using Clnt_noops<A const *>::from_msg;
  static int from_msg(char *msg, unsigned offset, unsigned limit, long ret,
                      A const *&arg, Dir_out, Cls_data)
  {
    offset = align_to<A>(offset);
    arg = reinterpret_cast<A const *>(msg + offset);
    if (L4_UNLIKELY(!check_size<A>(offset, limit, ret)))
      return -1;
 
    return offset + ret * sizeof(A);
  }
};
 
template<typename A, typename CLASS>
struct Svr_val_ops<Ret_array<A>, Dir_out, CLASS> :
  Svr_noops<Ret_array<A> >
{
  typedef Ret_array<A> ret_array;
  using Svr_noops<ret_array>::from_svr;
  static int from_svr(char *, unsigned offset, unsigned limit, long ret,
                      ret_array const &, Dir_out, CLASS)
  {
    offset = align_to<A>(offset);
    if (L4_UNLIKELY(!check_size<A>(offset, limit, ret)))
      return -1;
    offset += sizeof(A) * ret;
    return offset;
  }
 
  using Svr_noops<ret_array>::to_svr;
  static int to_svr(char *msg, unsigned offset, unsigned limit,
                    ret_array &arg, Dir_out, CLASS)
  {
    // there can be actually no limit check here, as this
    // is variably sized output array
    // FIXME: we could somehow makesure that this is the last
    //        output value...
    offset = align_to<A>(offset);
    arg = ret_array(reinterpret_cast<A*>(msg + offset),
                    (limit - offset) / sizeof(A));
    // FIXME: we dont know the length of the array here so, cheat
    return offset;
  }
};
} // namespace Msg
 
}}