DuplicateChecker.h

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 * Copyright (c) 2009-2010 Philipp Werner <philipp.werner@st.ovgu.de>
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#ifndef __DUPLICATECHECKER_H_D61F11F89E744A__
#define __DUPLICATECHECKER_H_D61F11F89E744A__


#include "debug.h"
#include "mw/afp/defrag/detail/BitArray.h"


namespace famouso {
    namespace mw {
        namespace afp {
            namespace defrag {


                template <class DCP>
                class DuplicateChecker {

                        detail::BitArray<DCP::max_fragments, typename DCP::Allocator> fragment_arrived;

                    public:

                        bool new_fragment(const Headers<DCP> & header) {
                            if (fragment_arrived.size() <= header.fseq) {
                                // This will be called as rarely as reordering happens, because
                                // fragments with highest fseq are sent first.
                                if (!fragment_arrived.resize(header.fseq + 1)) {
                                    // Can not allocate memory for duplicate checking.
                                    // -> can not guarantee service
                                    // -> mark fragment as duplicate to drop it (avoid
                                    //    incorrect reassembly)
                                    ::logging::log::emit< ::logging::Warning>()
                                        << PROGMEMSTRING("AFP: Out of memory -> drop")
                                        << ::logging::log::endl;
                                    return false;
                                }
                            }

                            detail::Bit fa = fragment_arrived[header.fseq];
                            if (fa.value() == true) {
                                return false;
                            } else {
                                fa.set();
                                return true;
                            }
                        }
                };


            } // namespace defrag
        } // namespace afp
    } // namespace mw
} // namespace famouso


#endif // __DUPLICATECHECKER_H_D61F11F89E744A__