MeshCore/src/helpers/SimpleMeshTables.h

#pragma once

#include <Mesh.h>

#ifdef ESP32
  #include <FS.h>
#endif

#define MAX_PACKET_HASHES  128

class SimpleMeshTables : public mesh::MeshTables {
  uint8_t _hashes[MAX_PACKET_HASHES*MAX_HASH_SIZE];
  int _next_idx;
  uint32_t _direct_dups, _flood_dups;

public:
  SimpleMeshTables() { 
    memset(_hashes, 0, sizeof(_hashes));
    _next_idx = 0;
    _direct_dups = _flood_dups = 0;
  }

#ifdef ESP32
  void restoreFrom(File f) {
    f.read(_hashes, sizeof(_hashes));
    f.read((uint8_t *) &_next_idx, sizeof(_next_idx));
  }
  void saveTo(File f) {
    f.write(_hashes, sizeof(_hashes));
    f.write((const uint8_t *) &_next_idx, sizeof(_next_idx));
  }
#endif

  bool hasSeen(const mesh::Packet* packet) override {
    uint8_t hash[MAX_HASH_SIZE];
    packet->calculatePacketHash(hash);

    const uint8_t* sp = _hashes;
    for (int i = 0; i < MAX_PACKET_HASHES; i++, sp += MAX_HASH_SIZE) {
      if (memcmp(hash, sp, MAX_HASH_SIZE) == 0) { 
        if (packet->isRouteDirect()) {
          _direct_dups++;   // keep some stats
        } else {
          _flood_dups++;
        }
        return true;
      }
    }

    memcpy(&_hashes[_next_idx*MAX_HASH_SIZE], hash, MAX_HASH_SIZE);
    _next_idx = (_next_idx + 1) % MAX_PACKET_HASHES;  // cyclic table

    return false;
  }

  uint32_t getNumDirectDups() const { return _direct_dups; }
  uint32_t getNumFloodDups() const { return _flood_dups; }

};