--- /dev/null
+// $Id$
+//
+// 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 ListBParser internal header */
+
+#ifndef IH_SENF_Packets_ListBParser_
+#define IH_SENF_Packets_ListBParser_ 1
+
+// Custom includes
+#include "ListParser.ih"
+
+///////////////////////////////ih.p////////////////////////////////////////
+
+namespace senf {
+namespace detail {
+
+ /** \brief Internal: ListPolicy defing the ListBParser parser
+ \internal
+ \see \ref ListBParser
+ */
+ template <class ElementParser, class AuxPolicy>
+ 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 <class Arg> 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
+ {
+ typedef PacketParserBase::data_iterator data_iterator;
+ typedef PacketParserBase::state_type state_type;
+ typedef PacketParserBase::size_type size_type;
+
+ typedef ListBParser_Policy<ElementParser, AuxPolicy> 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 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 <class ElementParser, class AuxPolicy>
+ struct ListParserPolicy<ElementParser, AuxPolicy, senf::detail::auxtag::bytes>
+ {
+ typedef ListBParser_Policy<ElementParser, AuxPolicy> type;
+ };
+
+ template <class ElementParser, class AuxPolicy, class Transform>
+ struct ListParserPolicy<ElementParser, AuxPolicy,
+ senf::detail::auxtag::transform<Transform,
+ senf::detail::auxtag::bytes> >
+ {
+ typedef ListBParser_Policy< ElementParser,
+ TransformAuxParserPolicy<AuxPolicy, Transform> > type;
+ };
+
+#endif
+
+}}
+
+///////////////////////////////ih.e////////////////////////////////////////
+#endif
+
+\f
+// 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:
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