OutOfOrderEventDataReconstructor.h

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#ifndef __OUTOFORDEREVENTDATARECONSTRUCTOR_H_3E331BC5510F68__
#define __OUTOFORDEREVENTDATARECONSTRUCTOR_H_3E331BC5510F68__


#include "debug.h"

#include "mw/afp/defrag/detail/VarHeaderLength.h"

#include <string.h>


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


                template <class DCP>
                class OutOfOrderEventDataReconstructor {

                        typedef typename DCP::SizeProp::elen_t elen_t;
                        typedef typename DCP::SizeProp::flen_t flen_t;
                        typedef typename DCP::SizeProp::fcount_t fcount_t;

                        typedef class DCP::DefragStatistics Statistics;
                        typedef class DCP::Allocator Allocator;
                        typedef detail::VarHeaderLength<DCP> VHL;
                        typedef typename VHL::eelen_t eelen_t;

                    public:

                        typedef NoFECHeaderSupport<DCP> FECHeaderPolicy;

                    protected:

                        uint8_t * event_data;             
                        uint8_t * behind_event_data;      
                        elen_t event_length;              

                        bool event_fragment_count_final;  
                        fcount_t event_fragment_count;    

                        fcount_t arrived_fragment_count;  

                        flen_t no_ext_mtu;                


                        void realloc_event_data(fcount_t new_fragment_count) {
                            eelen_t old_len = behind_event_data - event_data;
                            eelen_t new_len = VHL::get_payload(new_fragment_count, no_ext_mtu);

                            uint8_t * new_data = Allocator::alloc(new_len);
                            if (!new_data) {
                                ::logging::log::emit< ::logging::Warning>()
                                    << PROGMEMSTRING("AFP: Out of memory -> drop")
                                    << ::logging::log::endl;
                                no_ext_mtu = 0;
                                return;
                            }

                            memcpy(new_data + (new_len - old_len), event_data, old_len);
                            Allocator::free(event_data);

                            event_data = new_data;
                            behind_event_data = new_data + new_len;
                            event_fragment_count = new_fragment_count;
                        }
                    public:

                        OutOfOrderEventDataReconstructor(flen_t no_ext_mtu)
                                : event_data(0), event_length(0),
                                event_fragment_count_final(false), event_fragment_count(0),
                                arrived_fragment_count(0), no_ext_mtu(no_ext_mtu) {
                        }

                        ~OutOfOrderEventDataReconstructor() {
                            // Hack: check whether there is a derived class
                            // - event_data will surely be always not equal to the maximum pointer value
                            // - set event_data to maximum pointer in derived class if there is one
                            if (event_data != reinterpret_cast<uint8_t *>(-1)) {
                                // There is no derived class

                                // ... this check may have to be done in derived class
                                if (!is_complete())
                                    Statistics::event_incomplete();

                                Statistics::fragments_currently_expected_sub(event_fragment_count - arrived_fragment_count);
                                if (event_data)
                                    Allocator::free(event_data);
                            }
                        }

                        void put_fragment(const Headers<DCP> & header, const uint8_t * data, flen_t length) {
                            // Only last fragment may be smaller than maximum
                            FOR_FAMOUSO_ASSERT_ONLY(bool wrong_mtu_or_frag_len = length != no_ext_mtu - VHL::get_basic_header_len(header.fseq) && header.fseq != 0);
                            FAMOUSO_ASSERT(!wrong_mtu_or_frag_len); // Wrong MTU will lead to undefined behaviour
                            FAMOUSO_ASSERT(!is_complete());         // Event should not be already complete

                            if (no_ext_mtu == 0)            // Do nothing on error status
                                return;
                            if (header.fec.occurs()) {      // Cannot handle events using FEC -> error
                                ::logging::log::emit< ::logging::Warning>()
                                    << PROGMEMSTRING("AFP: FEC not supported -> drop")
                                    << ::logging::log::endl;
                                goto set_error;
                            }

                            if (header.first_fragment)
                                event_fragment_count_final = true;

                            if (!event_data) {
                                // put_fragment() called first time
                                event_fragment_count = header.fseq + (header.first_fragment ? 1 : 2);

                                eelen_t buffer_length = VHL::get_payload(event_fragment_count, no_ext_mtu);
                                event_data = Allocator::alloc(buffer_length);
                                if (!event_data) {
                                    ::logging::log::emit< ::logging::Warning>()
                                        << PROGMEMSTRING("AFP: Out of memory -> drop")
                                        << ::logging::log::endl;
                                    goto set_error;
                                }
                                behind_event_data = event_data + buffer_length;

                                Statistics::fragments_expected(event_fragment_count);
                                Statistics::fragments_currently_expected_add(event_fragment_count - 1);

                            } else if (header.fseq >= event_fragment_count) {
                                // Current fragment much too late. It has to be placed somewhere in front of
                                // all data chunks received till now
                                fcount_t new_frag_count = header.fseq + 1;
                                fcount_t additional_frag = new_frag_count - event_fragment_count;

                                realloc_event_data(new_frag_count);

                                Statistics::fragments_expected(additional_frag);
                                Statistics::fragments_currently_expected_add(additional_frag - 1);

                            } else {
                                // Fragment fitting in allocated buffer
                                Statistics::fragments_currently_expected_sub(1);
                            }

                            // Copy into event_data buffer
                            memcpy(behind_event_data - VHL::get_payload(header.fseq + 1, no_ext_mtu), data, length);

                            arrived_fragment_count++;
                            event_length += length;

                            Statistics::fragment_used();

                            if (is_complete())
                                Statistics::event_complete();

                            return;

                        set_error:
                            no_ext_mtu = 0;
                            return;
                        }

                        bool is_complete() {
                            return arrived_fragment_count == event_fragment_count && event_fragment_count_final && !error();
                        }

                        uint8_t * get_data() {
                            FAMOUSO_ASSERT(is_complete());
                            return event_data;
                        }

                        elen_t get_length() {
                            FAMOUSO_ASSERT(is_complete());
                            return event_length;
                        }

                        bool error() {
                            return no_ext_mtu == 0;
                        }
                };


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


#endif // __OUTOFORDEREVENTDATARECONSTRUCTOR_H_3E331BC5510F68__