// $Id$
//
// Copyright (C) 2007
// Fraunhofer Institute for Open Communication Systems (FOKUS)
// Competence Center NETwork research (NET), St. Augustin, GERMANY
//     Stefan Bund <g0dil@berlios.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.

/** \file
    \brief PacketInterpreter inline template implementation */

//#include "PacketInterpreter.ih"

// Custom includes

#define prefix_ inline
///////////////////////////////cti.p///////////////////////////////////////

///////////////////////////////////////////////////////////////////////////
// senf::PacketInterpreterBase

// Interpreter chain access

template <class Type>
prefix_ bool senf::PacketInterpreterBase::is()
{
    { static void const * const _ ((void*)&Type::dump); (void) _; }
    return dynamic_cast< PacketInterpreter<Type>* >(this);
}

template <class Type>
prefix_ typename senf::PacketInterpreter<Type>::ptr senf::PacketInterpreterBase::as()
{
    { static void const * const _ ((void*)&Type::dump); (void) _; }
    return typename PacketInterpreter<Type>::ptr(
        static_cast< PacketInterpreter<Type>* >(this));
}

///////////////////////////////////////////////////////////////////////////
// senf::PacketInterpreter<PacketType>

template <class PacketType>
prefix_ senf::PacketInterpreter<PacketType>::~PacketInterpreter()
{
    parser_p()->~parser();
}

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::factory_t
senf::PacketInterpreter<PacketType>::factory()
{
    return & factory_;
}

// Create completely new packet

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::ptr
senf::PacketInterpreter<PacketType>::create()
{
    return create(initSize());
}

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::ptr
senf::PacketInterpreter<PacketType>::create(senf::NoInit_t)
{
    return create(0,senf::noinit);
}

template <class PacketType>
template <class ForwardReadableRange>
prefix_ typename senf::PacketInterpreter<PacketType>::ptr
senf::PacketInterpreter<PacketType>::create(ForwardReadableRange const & range)
{
    detail::PacketImpl::Guard p (new detail::PacketImpl(boost::begin(range),boost::end(range)));
    ptr pi (create(p.p,p.p->begin(),p.p->end(),Append));
    return pi;
}

// Create packet as new packet after a given packet

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::ptr
senf::PacketInterpreter<PacketType>::createAfter(PacketInterpreterBase::ptr packet)
{
    return createAfter(packet, initSize());
}

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::ptr
senf::PacketInterpreter<PacketType>::createAfter(PacketInterpreterBase::ptr packet, senf::NoInit_t)
{
    return createAfter(packet, 0, senf::noinit);
}

// Create clone of current packet

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::ptr
senf::PacketInterpreter<PacketType>::clone()
{
    return boost::static_pointer_cast<typename ptr::element_type>(PacketInterpreterBase::clone());
}

// Packet field access

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::parser
senf::PacketInterpreter<PacketType>::fields()
{
    return parser (data().begin(),&data());
}

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::parser *
senf::PacketInterpreter<PacketType>::fields_p()
{
    // This is somewhat awkward. We want to allow the user to access the packet's field using the
    // 'operator->' member of the packet class (the handle). Now, 'operator->' *must* return a
    // pointer to a non-dynamically allocated object. So where should it point to? We need to return
    // a pointer to a parser instance, but parser instances are designed to be transient (they are
    // invalidated whenever a packet's size is changed).

    // What we do is the following: parserStorage_ is an (initialy uninitialized) storage area
    // within the interpreter with enough space (and correct alignment) to take hold of a parser
    // instance. In the constructor we use placement new to construct a parser in this area which we
    // explicit dispose of in the destructor. Now, whenever the fields_p() member is called, we
    // destroy the parser object and recreate it. 

    // This does introduce one additional problem: It is not safe for multiple threads to
    // concurrently read from the same packet. On the other hand, the packet classes are not
    // syncronized in any way and are not safe to use from multiple threads anyways (e.g. the lazy
    // packet chain makes some read-only operations change the packet which is not thread safe).

    parser_p()->~parser();
    new (parser_p()) parser (data().begin(),&data());
    return parser_p();
}

////////////////////////////////////////
// private members

// Private structors

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::ptr
senf::PacketInterpreter<PacketType>::create(detail::PacketImpl * impl, iterator b, iterator e,
                                            Append_t)
{
    return ptr(new PacketInterpreter(impl,b,e,Append));
}

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::ptr
senf::PacketInterpreter<PacketType>::create(detail::PacketImpl * impl, iterator b, iterator e,
                                            Prepend_t)
{
    return ptr(new PacketInterpreter(impl,b,e,Prepend));
}

template <class PacketType>
prefix_ senf::PacketInterpreter<PacketType>::PacketInterpreter(detail::PacketImpl * impl,
                                                               iterator b, iterator e, Append_t)
    : PacketInterpreterBase(impl,b,e,Append)
{
    new (parser_p()) parser (data().begin(),&data());
}

template <class PacketType>
prefix_ senf::PacketInterpreter<PacketType>::PacketInterpreter(detail::PacketImpl * impl,
                                                               iterator b, iterator e, Prepend_t)
    : PacketInterpreterBase(impl,b,e,Prepend)
{
    new (parser_p()) parser (data().begin(),&data());
}

// PacketType access

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::size_type
senf::PacketInterpreter<PacketType>::initSize()
{
    return type::initSize();
}

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::size_type
senf::PacketInterpreter<PacketType>::initHeadSize()
{
    size_type sz (type::initHeadSize());
    return  sz == size_type(-1) ? initSize() : sz ;
}

template <class PacketType>
prefix_ void senf::PacketInterpreter<PacketType>::init()
{
    return type::init(ConcretePacket<PacketType>(ptr(this)));
}

template <class PacketType>
prefix_ typename senf::PacketInterpreter<PacketType>::parser *
senf::PacketInterpreter<PacketType>::parser_p()
{
    return reinterpret_cast<parser *>(&parserStorage_);
}

///////////////////////////////cti.e///////////////////////////////////////
#undef prefix_


// Local Variables:
// mode: c++
// fill-column: 100
// c-file-style: "senf"
// indent-tabs-mode: nil
// ispell-local-dictionary: "american"
// compile-command: "scons -u test"
// comment-column: 40
// End: