// $Id$ // // Copyright (C) 2007 // Fraunhofer Institute for Open Communication Systems (FOKUS) // Competence Center NETwork research (NET), St. Augustin, GERMANY // Stefan Bund // // 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 ListBParser internal header */ #ifndef IH_SENF_Packets_ListBParser_ #define IH_SENF_Packets_ListBParser_ 1 // Custom includes #include "ListParser.ih" //-///////////////////////////////////////////////////////////////////////////////////////////////// namespace senf { namespace detail { /** \brief Internal: ListPolicy defing the ListBParser parser \internal \see \ref ListParser */ template struct ListBParser_Policy : public AuxPolicy { // This policy needs to work around a serious problem with this type of list: When we change // the size of any (direct or indirect) sub-element of the list, this will change will // render the list completely invalid and un-parseable since the 'byte' field will now be // invalid. // // The solution we apply is to store the *size* (i.e. the number of elements) of the list // when creating the container wrapper. We also maintain this value across insert/erase // statements. Additionally we also safe the complete size of the data container (the vector // holding the bytes). Since we only allow packet changes through this container while it // exists, any change in the container size must be a change within this list and therefore // mandates an update of the 'bytes' field. // // The list container wrapper will call 'update' policy member before every access to the // container and also in the destructor. This gives us a chance to fix the bytes header // before the invalid header is seen by anyone (This is so, since we only allow access to // the list through the container wrapper ...). Since we know the number of list elements, // we can always find the correct 'bytes' value by traversing the list for that number of // elements. // // By caching the container size, all this can be made reasonably efficient and usable: The // updates are done automatically by only if needed. It would of course be more efficient to // just apply the size change directly to the bytes header (no need to traverse the // list). However, the implementation of this approach would be much more complex and even // more invasive and would probably suffer from the same restrictions to the user. struct container_policy; typedef PacketParserBase::data_iterator data_iterator; typedef PacketParserBase::state_type state_type; typedef PacketParserBase::size_type size_type; typedef ElementParser element_type; typedef ListParser< ListBParser_Policy > parser_type; typedef ListParser_Container< container_policy > container_type; static const size_type init_bytes = AuxPolicy::aux_bytes; ListBParser_Policy(); template ListBParser_Policy(Arg const & arg); size_type bytes (data_iterator i, state_type s) const; size_type size (data_iterator i, state_type s) const; void init (data_iterator i, state_type s) const; /** \brief Internal: ListBParser container/wrapper policy */ struct container_policy : public AuxPolicy::WrapperPolicy { typedef PacketParserBase::data_iterator data_iterator; typedef PacketParserBase::state_type state_type; typedef PacketParserBase::size_type size_type; typedef ListBParser_Policy parser_policy; typedef typename parser_policy::element_type element_type; typedef typename parser_policy::parser_type parser_type; typedef typename parser_policy::container_type container_type; static const size_type init_bytes = parser_policy::init_bytes; container_policy(parser_policy const & p); size_type bytes (data_iterator i, state_type s) const; size_type size (data_iterator i, state_type s) const; void init (data_iterator i, state_type s); void construct (container_type & c) const; void destruct (container_type & c) const; void erase (container_type & c, data_iterator p); void insert (container_type & c, data_iterator p); void update (container_type const & c) const; /** \brief Internal: ListBParser specific iterator data */ struct iterator_data {}; data_iterator setBegin (container_type const & c, iterator_data & d) const; data_iterator setEnd (container_type const & c, iterator_data & d) const; void setFromPosition (container_type const & c, iterator_data & d, data_iterator p) const; data_iterator next (container_type const & c, iterator_data & d) const; data_iterator raw (container_type const & c, iterator_data const & d) const; size_type n_; mutable size_type container_size_; }; }; #ifndef DOXYGEN template struct ListParserPolicy { typedef ListBParser_Policy type; }; template struct ListParserPolicy > { typedef ListBParser_Policy< ElementParser, TransformAuxParserPolicy > type; }; #endif }} //-///////////////////////////////////////////////////////////////////////////////////////////////// #endif // Local Variables: // mode: c++ // fill-column: 100 // comment-column: 40 // c-file-style: "senf" // indent-tabs-mode: nil // ispell-local-dictionary: "american" // compile-command: "scons -u test" // End: