text: #pragma once
  
  #include "visited_list_pool.h"
  #include "hnswlib.h"
  #include <random>
  #include <iostream>
  #include <fstream>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  #include <algorithm>
  #include <atomic>
  #include <unordered_set>
  #include <unordered_map>
  
  
  
  
  namespace hnswlib {
      typedef unsigned int tableint;
      typedef unsigned int linklistsizeint;
  
      template<typename dist_t>
      class HierarchicalNSW : public AlgorithmInterface<dist_t> {
      public:
  
          HierarchicalNSW(SpaceInterface<dist_t> *s) {
  
          }
  
          HierarchicalNSW(SpaceInterface<dist_t> *s, const std::string &location, bool nmslib = false, size_t max_elements=0) {
              loadIndex(location, s, max_elements);
          }
  
          HierarchicalNSW(SpaceInterface<dist_t> *s, size_t max_elements, size_t M = 16, size_t ef_construction = 200, size_t random_seed = 100) :
                  link_list_locks_(max_elements), element_levels_(max_elements) {
              max_elements_ = max_elements;
  
  
              data_size_ = s->get_data_size();
              fstdistfunc_ = s->get_dist_func();
              dist_func_param_ = s->get_dist_func_param();
              M_ = M;
              maxM_ = M_;
              maxM0_ = M_ * 2;
              ef_construction_ = std::max(ef_construction,M_);
              ef_ = 10;
  
              level_generator_.seed(random_seed);
              
              size_links_level0_ = maxM0_ * sizeof(tableint) + sizeof(linklistsizeint);
              size_data_per_element_ = size_links_level0_ + data_size_ + sizeof(labeltype);
              offsetData_ = size_links_level0_;
              label_offset_ = size_links_level0_ + data_size_;
              offsetLevel0_ = 0;
  
              data_level0_memory_ = (char *) malloc(max_elements_ * size_data_per_element_);
              if (data_level0_memory_ == nullptr)
                  throw std::runtime_error("Not enough memory");
  
              cur_element_count = 0;
  
              visited_list_pool_ = new VisitedListPool(1, max_elements);
  
  
  
              //initializations for special treatment of the first node
              enterpoint_node_ = -1;
              maxlevel_ = -1;
  
              linkLists_ = (char **) malloc(sizeof(void *) * max_elements_);
              size_links_per_element_ = maxM_ * sizeof(tableint) + sizeof(linklistsizeint);
              mult_ = 1 / log(1.0 * M_);
              revSize_ = 1.0 / mult_;
          }
  
          struct CompareByFirst {
              constexpr bool operator()(std::pair<dist_t, tableint> const &a,
                                        std::pair<dist_t, tableint> const &b) const noexcept {
                  return a.first < b.first;
              }
          };
  
          ~HierarchicalNSW() {
  
              free(data_level0_memory_);
              for (tableint i = 0; i < cur_element_count; i++) {
                  if (element_levels_[i] > 0)
                      free(linkLists_[i]);
              }
              free(linkLists_);
              delete visited_list_pool_;
          }
  
          size_t max_elements_;
          size_t cur_element_count;
          size_t size_data_per_element_;
          size_t size_links_per_element_;
  
          size_t M_;
          size_t maxM_;
          size_t maxM0_;
          size_t ef_construction_;
  
          double mult_, revSize_;
          int maxlevel_;
  
  
          VisitedListPool *visited_list_pool_;
          std::mutex cur_element_count_guard_;
  
          std::vector<std::mutex> link_list_locks_;
          tableint enterpoint_node_;
  
  
  
          size_t size_links_level0_;
          size_t offsetData_, offsetLevel0_;
  
  
          char *data_level0_memory_;
          char **linkLists_;
          std::vector<int> element_levels_;
  
  
          size_t data_size_;
          size_t label_offset_;
          DISTFUNC<dist_t> fstdistfunc_;
          void *dist_func_param_;
  
          std::default_random_engine level_generator_;
  
          inline labeltype getExternalLabel(tableint internal_id) const {
              return *((labeltype *) (data_level0_memory_ + internal_id * size_data_per_element_ + label_offset_));
          }
  
          inline labeltype *getExternalLabeLp(tableint internal_id) const {
              return (labeltype *) (data_level0_memory_ + internal_id * size_data_per_element_ + label_offset_);
          }
  
          inline char *getDataByInternalId(tableint internal_id) const {
              return (data_level0_memory_ + internal_id * size_data_per_element_ + offsetData_);
          }
  
          int getRandomLevel(double reverse_size) {
              std::uniform_real_distribution<double> distribution(0.0, 1.0);
              double r = -log(distribution(level_generator_)) * reverse_size;
              return (int) r;
          }
  
          std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst>
          searchBaseLayer(tableint enterpoint_id, void *data_point, int layer) {
              VisitedList *vl = visited_list_pool_->getFreeVisitedList();
              vl_type *visited_array = vl->mass;
              vl_type visited_array_tag = vl->curV;
  
              std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst> top_candidates;
              std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst> candidateSet;
              dist_t dist = fstdistfunc_(data_point, getDataByInternalId(enterpoint_id), dist_func_param_);
  
              top_candidates.emplace(dist, enterpoint_id);
              candidateSet.emplace(-dist, enterpoint_id);
              visited_array[enterpoint_id] = visited_array_tag;
              dist_t lowerBound = dist;
  
              while (!candidateSet.empty()) {
  
                  std::pair<dist_t, tableint> curr_el_pair = candidateSet.top();
  
                  if ((-curr_el_pair.first) > lowerBound) {
                      break;
                  }
                  candidateSet.pop();
  
                  tableint curNodeNum = curr_el_pair.second;
  
                  std::unique_lock <std::mutex> lock(link_list_locks_[curNodeNum]);
  
                  int *data;// = (int *)(linkList0_ + curNodeNum * size_links_per_element0_);
                  if (layer == 0)
                      data = (int *) (data_level0_memory_ + curNodeNum * size_data_per_element_ + offsetLevel0_);
                  else
                      data = (int *) (linkLists_[curNodeNum] + (layer - 1) * size_links_per_element_);
                  int size = *data;
                  tableint *datal = (tableint *) (data + 1);
                  _mm_prefetch((char *) (visited_array + *(data + 1)), _MM_HINT_T0);
                  _mm_prefetch((char *) (visited_array + *(data + 1) + 64), _MM_HINT_T0);
                  _mm_prefetch(getDataByInternalId(*datal), _MM_HINT_T0);
                  _mm_prefetch(getDataByInternalId(*(datal + 1)), _MM_HINT_T0);
  
                  for (int j = 0; j < size; j++) {
                      tableint candidate_id = *(datal + j);
                      _mm_prefetch((char *) (visited_array + *(datal + j + 1)), _MM_HINT_T0);
                      _mm_prefetch(getDataByInternalId(*(datal + j + 1)), _MM_HINT_T0);
                      if (visited_array[candidate_id] == visited_array_tag) continue;
                      visited_array[candidate_id] = visited_array_tag;
                      char *currObj1 = (getDataByInternalId(candidate_id));
  
                      dist_t dist1 = fstdistfunc_(data_point, currObj1, dist_func_param_);
                      if (top_candidates.top().first > dist1 || top_candidates.size() < ef_construction_) {
                          candidateSet.emplace(-dist1, candidate_id);
                          _mm_prefetch(getDataByInternalId(candidateSet.top().second), _MM_HINT_T0);
                          top_candidates.emplace(dist1, candidate_id);
                          if (top_candidates.size() > ef_construction_) {
                              top_candidates.pop();
                          }
                          lowerBound = top_candidates.top().first;
                      }
                  }
              }
              visited_list_pool_->releaseVisitedList(vl);
  
              return top_candidates;
          }
  
          std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst>
          searchBaseLayerST(tableint ep_id, const void *data_point, size_t ef) const {
              VisitedList *vl = visited_list_pool_->getFreeVisitedList();
              vl_type *visited_array = vl->mass;
              vl_type visited_array_tag = vl->curV;
  
              std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst> top_candidates;
              std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst> candidate_set;
              dist_t dist = fstdistfunc_(data_point, getDataByInternalId(ep_id), dist_func_param_);
  
              top_candidates.emplace(dist, ep_id);
              candidate_set.emplace(-dist, ep_id);
              visited_array[ep_id] = visited_array_tag;
              dist_t lower_bound = dist;
  
              while (!candidate_set.empty()) {
  
                  std::pair<dist_t, tableint> current_node_pair = candidate_set.top();
  
                  if ((-current_node_pair.first) > lower_bound) {
                      break;
                  }
                  candidate_set.pop();
  
                  tableint current_node_id = current_node_pair.second;
                  int *data = (int *) (data_level0_memory_ + current_node_id * size_data_per_element_ + offsetLevel0_);
                  int size = *data;
                  _mm_prefetch((char *) (visited_array + *(data + 1)), _MM_HINT_T0);
                  _mm_prefetch((char *) (visited_array + *(data + 1) + 64), _MM_HINT_T0);
                  _mm_prefetch(data_level0_memory_ + (*(data + 1)) * size_data_per_element_ + offsetData_, _MM_HINT_T0);
                  _mm_prefetch((char *) (data + 2), _MM_HINT_T0);
  
                  for (int j = 1; j <= size; j++) {
                      int candidate_id = *(data + j);
                      _mm_prefetch((char *) (visited_array + *(data + j + 1)), _MM_HINT_T0);
                      _mm_prefetch(data_level0_memory_ + (*(data + j + 1)) * size_data_per_element_ + offsetData_,
                                   _MM_HINT_T0);////////////
                      if (!(visited_array[candidate_id] == visited_array_tag)) {
  
                          visited_array[candidate_id] = visited_array_tag;
  
                          char *currObj1 = (getDataByInternalId(candidate_id));
                          dist_t dist = fstdistfunc_(data_point, currObj1, dist_func_param_);
  
                          if (top_candidates.top().first > dist || top_candidates.size() < ef) {
                              candidate_set.emplace(-dist, candidate_id);
                              _mm_prefetch(data_level0_memory_ + candidate_set.top().second * size_data_per_element_ +
                                           offsetLevel0_,///////////
                                           _MM_HINT_T0);////////////////////////
  
                              top_candidates.emplace(dist, candidate_id);
  
                              if (top_candidates.size() > ef) {
                                  top_candidates.pop();
                              }
                              lower_bound = top_candidates.top().first;
                          }
                      }
                  }
              }
  
              visited_list_pool_->releaseVisitedList(vl);
              return top_candidates;
          }
  
          void getNeighborsByHeuristic2(
                  std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst> &top_candidates,
                  const size_t M) {
              if (top_candidates.size() < M) {
                  return;
              }
              std::priority_queue<std::pair<dist_t, tableint>> queue_closest;
              std::vector<std::pair<dist_t, tableint>> return_list;
              while (top_candidates.size() > 0) {
                  queue_closest.emplace(-top_candidates.top().first, top_candidates.top().second);
                  top_candidates.pop();
              }
  
              while (queue_closest.size()) {
                  if (return_list.size() >= M)
                      break;
                  std::pair<dist_t, tableint> curent_pair = queue_closest.top();
                  dist_t dist_to_query = -curent_pair.first;
                  queue_closest.pop();
                  bool good = true;
                  for (std::pair<dist_t, tableint> second_pair : return_list) {
                      dist_t curdist =
                              fstdistfunc_(getDataByInternalId(second_pair.second),
                                           getDataByInternalId(curent_pair.second),
                                           dist_func_param_);;
                      if (curdist < dist_to_query) {
                          good = false;
                          break;
                      }
                  }
                  if (good) {
                      return_list.push_back(curent_pair);
                  }
  
  
              }
  
              for (std::pair<dist_t, tableint> curent_pair : return_list) {
  
                  top_candidates.emplace(-curent_pair.first, curent_pair.second);
              }
          }
  
  
          linklistsizeint *get_linklist0(tableint internal_id) {
              return (linklistsizeint *) (data_level0_memory_ + internal_id * size_data_per_element_ + offsetLevel0_);
          };
  
          linklistsizeint *get_linklist0(tableint internal_id, char *data_level0_memory_) {
              return (linklistsizeint *) (data_level0_memory_ + internal_id * size_data_per_element_ + offsetLevel0_);
          };
  
          linklistsizeint *get_linklist(tableint internal_id, int level) {
              return (linklistsizeint *) (linkLists_[internal_id] + (level - 1) * size_links_per_element_);
          };
  
          void mutuallyConnectNewElement(void *data_point, tableint cur_c,
                                         std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst> top_candidates,
                                         int level) {
  
              size_t Mcurmax = level ? maxM_ : maxM0_;
              getNeighborsByHeuristic2(top_candidates, M_);
              if (top_candidates.size() > M_)
                  throw std::runtime_error("Should be not be more than M_ candidates returned by the heuristic");
  
              std::vector<tableint> selectedNeighbors;
              selectedNeighbors.reserve(M_);
              while (top_candidates.size() > 0) {
                  selectedNeighbors.push_back(top_candidates.top().second);
                  top_candidates.pop();
              }
              {
                  linklistsizeint *ll_cur;
                  if (level == 0)
                      ll_cur = get_linklist0(cur_c);
                  else
                      ll_cur = get_linklist(cur_c, level);
  
                  if (*ll_cur) {
                      throw std::runtime_error("The newly inserted element should have blank link list");
                  }
                  *ll_cur = selectedNeighbors.size();
                  tableint *data = (tableint *) (ll_cur + 1);
  
  
                  for (size_t idx = 0; idx < selectedNeighbors.size(); idx++) {
                      if (data[idx])
                          throw std::runtime_error("Possible memory corruption");
                      if (level > element_levels_[selectedNeighbors[idx]])
                          throw std::runtime_error("Trying to make a link on a non-existent level");
  
                      data[idx] = selectedNeighbors[idx];
  
                  }
              }
              for (size_t idx = 0; idx < selectedNeighbors.size(); idx++) {
  
                  std::unique_lock <std::mutex> lock(link_list_locks_[selectedNeighbors[idx]]);
  
  
                  linklistsizeint *ll_other;
                  if (level == 0)
                      ll_other = get_linklist0(selectedNeighbors[idx]);
                  else
                      ll_other = get_linklist(selectedNeighbors[idx], level);
                  size_t sz_link_list_other = *ll_other;
  
  
                  if (sz_link_list_other > Mcurmax)
                      throw std::runtime_error("Bad value of sz_link_list_other");
                  if (selectedNeighbors[idx] == cur_c)
                      throw std::runtime_error("Trying to connect an element to itself");
                  if (level > element_levels_[selectedNeighbors[idx]])
                      throw std::runtime_error("Trying to make a link on a non-existent level");
  
                  tableint *data = (tableint *) (ll_other + 1);
                  if (sz_link_list_other < Mcurmax) {
                      data[sz_link_list_other] = cur_c;
                      *ll_other = sz_link_list_other + 1;
                  } else {
                      // finding the "weakest" element to replace it with the new one
                      dist_t d_max = fstdistfunc_(getDataByInternalId(cur_c), getDataByInternalId(selectedNeighbors[idx]),
                                                  dist_func_param_);
                      // Heuristic:
                      std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst> candidates;
                      candidates.emplace(d_max, cur_c);
  
                      for (size_t j = 0; j < sz_link_list_other; j++) {
                          candidates.emplace(
                                  fstdistfunc_(getDataByInternalId(data[j]), getDataByInternalId(selectedNeighbors[idx]),
                                               dist_func_param_), data[j]);
                      }
  
                      getNeighborsByHeuristic2(candidates, Mcurmax);
  
                      int indx = 0;
                      while (candidates.size() > 0) {
                          data[indx] = candidates.top().second;
                          candidates.pop();
                          indx++;
                      }
                      *ll_other = indx;
                      // Nearest K:
                      /*int indx = -1;
                      for (int j = 0; j < sz_link_list_other; j++) {
                          dist_t d = fstdistfunc_(getDataByInternalId(data[j]), getDataByInternalId(rez[idx]), dist_func_param_);
                          if (d > d_max) {
                              indx = j;
                              d_max = d;
                          }
                      }
                      if (indx >= 0) {
                          data[indx] = cur_c;
                      } */
                  }
  
              }
          }
  
          std::mutex global;
          size_t ef_;
  
          void setEf(size_t ef) {
              ef_ = ef;
          }
  
  
          std::priority_queue<std::pair<dist_t, tableint>> searchKnnInternal(void *query_data, int k) {
              tableint currObj = enterpoint_node_;
              dist_t curdist = fstdistfunc_(query_data, getDataByInternalId(enterpoint_node_), dist_func_param_);
  
              for (size_t level = maxlevel_; level > 0; level--) {
                  bool changed = true;
                  while (changed) {
                      changed = false;
                      int *data;
                      data = (int *) (linkLists_[currObj] + (level - 1) * size_links_per_element_);
                      int size = *data;
                      tableint *datal = (tableint *) (data + 1);
                      for (int i = 0; i < size; i++) {
                          tableint cand = datal[i];
                          if (cand < 0 || cand > max_elements_)
                              throw std::runtime_error("cand error");
                          dist_t d = fstdistfunc_(query_data, getDataByInternalId(cand), dist_func_param_);
  
                          if (d < curdist) {
                              curdist = d;
                              currObj = cand;
                              changed = true;
                          }
                      }
                  }
              }
  
              //std::priority_queue< std::pair< dist_t, tableint  >> top_candidates = searchBaseLayer(currObj, query_data, 0);
              std::priority_queue<std::pair<dist_t, tableint  >> top_candidates = searchBaseLayerST(currObj, query_data,
                                                                                                    ef_);
              while (top_candidates.size() > k) {
                  top_candidates.pop();
              }
              return top_candidates;
          };
  
          void saveIndex(const std::string &location) {
              std::ofstream output(location, std::ios::binary);
              std::streampos position;
  
              writeBinaryPOD(output, offsetLevel0_);
              writeBinaryPOD(output, max_elements_);
              writeBinaryPOD(output, cur_element_count);
              writeBinaryPOD(output, size_data_per_element_);
              writeBinaryPOD(output, label_offset_);
              writeBinaryPOD(output, offsetData_);
              writeBinaryPOD(output, maxlevel_);
              writeBinaryPOD(output, enterpoint_node_);
              writeBinaryPOD(output, maxM_);
  
              writeBinaryPOD(output, maxM0_);
              writeBinaryPOD(output, M_);
              writeBinaryPOD(output, mult_);
              writeBinaryPOD(output, ef_construction_);
  
              output.write(data_level0_memory_, cur_element_count * size_data_per_element_);
  
              for (size_t i = 0; i < cur_element_count; i++) {
                  unsigned int linkListSize = element_levels_[i] > 0 ? size_links_per_element_ * element_levels_[i] : 0;
                  writeBinaryPOD(output, linkListSize);
                  if (linkListSize)
                      output.write(linkLists_[i], linkListSize);
              }
              output.close();
          }
  
          void loadIndex(const std::string &location, SpaceInterface<dist_t> *s, size_t max_elements_i=0) {
  
  
              std::ifstream input(location, std::ios::binary);
  
              // get file size:
              input.seekg(0,input.end);
              std::streampos total_filesize=input.tellg();
              input.seekg(0,input.beg);
  
              readBinaryPOD(input, offsetLevel0_);
              readBinaryPOD(input, max_elements_);
              readBinaryPOD(input, cur_element_count);
  
              size_t max_elements=max_elements_i;
              if(max_elements < cur_element_count)
                  max_elements = max_elements_;
              max_elements_ = max_elements;
              readBinaryPOD(input, size_data_per_element_);
              readBinaryPOD(input, label_offset_);
              readBinaryPOD(input, offsetData_);
              readBinaryPOD(input, maxlevel_);
              readBinaryPOD(input, enterpoint_node_);
  
              readBinaryPOD(input, maxM_);
              readBinaryPOD(input, maxM0_);
              readBinaryPOD(input, M_);
              readBinaryPOD(input, mult_);
              readBinaryPOD(input, ef_construction_);
  
  
              data_size_ = s->get_data_size();
              fstdistfunc_ = s->get_dist_func();
              dist_func_param_ = s->get_dist_func_param();
  
              /// Legacy, check that everything is ok
  
              bool old_index=false;
  
              auto pos=input.tellg();
              input.seekg(cur_element_count * size_data_per_element_,input.cur);
              for (size_t i = 0; i < cur_element_count; i++) {
                  if(input.tellg() < 0 || input.tellg()>=total_filesize){
                      old_index = true;
                      break;
                  }
  
                  unsigned int linkListSize;
                  readBinaryPOD(input, linkListSize);
                  if (linkListSize != 0) {
                      input.seekg(linkListSize,input.cur);
                  }
              }
  
              // check if file is ok, if not this is either corrupted or old index
              if(input.tellg()!=total_filesize)
                  old_index = true;
  
              if (old_index) {
                  std::cerr << "Warning: loading of old indexes will be deprecated before 2019.\n"
                            << "Please resave the index in the new format.\n";
              }
              input.clear();
              input.seekg(pos,input.beg);
  
  
              data_level0_memory_ = (char *) malloc(max_elements * size_data_per_element_);
              input.read(data_level0_memory_, cur_element_count * size_data_per_element_);
  
              if(old_index)
                  input.seekg(((max_elements_-cur_element_count) * size_data_per_element_), input.cur);
  
  
              size_links_per_element_ = maxM_ * sizeof(tableint) + sizeof(linklistsizeint);
  
  
              size_links_level0_ = maxM0_ * sizeof(tableint) + sizeof(linklistsizeint);
              std::vector<std::mutex>(max_elements).swap(link_list_locks_);
  
  
              visited_list_pool_ = new VisitedListPool(1, max_elements);
  
  
              linkLists_ = (char **) malloc(sizeof(void *) * max_elements);
              element_levels_ = std::vector<int>(max_elements);
              revSize_ = 1.0 / mult_;
              ef_ = 10;
              for (size_t i = 0; i < cur_element_count; i++) {
                  unsigned int linkListSize;
                  readBinaryPOD(input, linkListSize);
                  if (linkListSize == 0) {
                      element_levels_[i] = 0;
  
                      linkLists_[i] = nullptr;
                  } else {
                      element_levels_[i] = linkListSize / size_links_per_element_;
                      linkLists_[i] = (char *) malloc(linkListSize);
                      input.read(linkLists_[i], linkListSize);
                  }
              }
              input.close();
  
              return;
          }
  
          void addPoint(void *data_point, labeltype label)
          {
              addPoint(data_point, label,-1);
          };
  
          tableint addPoint(void *data_point, labeltype label, int level) {
  
              tableint cur_c = 0;
              {
                  std::unique_lock <std::mutex> lock(cur_element_count_guard_);
                  if (cur_element_count >= max_elements_) {
                      throw std::runtime_error("The number of elements exceeds the specified limit");
                  };
                  cur_c = cur_element_count;
                  cur_element_count++;
              }
              std::unique_lock <std::mutex> lock_el(link_list_locks_[cur_c]);
              int curlevel = getRandomLevel(mult_);
              if (level > 0)
                  curlevel = level;
  
              element_levels_[cur_c] = curlevel;
  
  
              std::unique_lock <std::mutex> templock(global);
              int maxlevelcopy = maxlevel_;
              if (curlevel <= maxlevelcopy)
                  templock.unlock();
              tableint currObj = enterpoint_node_;
  
  
              memset(data_level0_memory_ + cur_c * size_data_per_element_ + offsetLevel0_, 0, size_data_per_element_);
  
              // Initialisation of the data and label
              memcpy(getExternalLabeLp(cur_c), &label, sizeof(labeltype));
              memcpy(getDataByInternalId(cur_c), data_point, data_size_);
  
  
              if (curlevel) {
                  linkLists_[cur_c] = (char *) malloc(size_links_per_element_ * curlevel + 1);
                  memset(linkLists_[cur_c], 0, size_links_per_element_ * curlevel + 1);
              }
              if ((signed)currObj != -1) {
  
  
                  if (curlevel < maxlevelcopy) {
  
                      dist_t curdist = fstdistfunc_(data_point, getDataByInternalId(currObj), dist_func_param_);
                      for (int level = maxlevelcopy; level > curlevel; level--) {
  
  
                          bool changed = true;
                          while (changed) {
                              changed = false;
                              int *data;
                              std::unique_lock <std::mutex> lock(link_list_locks_[currObj]);
                              data = (int *) (linkLists_[currObj] + (level - 1) * size_links_per_element_);
                              int size = *data;
                              tableint *datal = (tableint *) (data + 1);
                              for (int i = 0; i < size; i++) {
                                  tableint cand = datal[i];
                                  if (cand < 0 || cand > max_elements_)
                                      throw std::runtime_error("cand error");
                                  dist_t d = fstdistfunc_(data_point, getDataByInternalId(cand), dist_func_param_);
                                  if (d < curdist) {
                                      curdist = d;
                                      currObj = cand;
                                      changed = true;
                                  }
                              }
                          }
                      }
                  }
  
                  for (int level = std::min(curlevel, maxlevelcopy); level >= 0; level--) {
                      if (level > maxlevelcopy || level < 0)
                          throw std::runtime_error("Level error");
  
                      std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst> top_candidates = searchBaseLayer(
                              currObj, data_point, level);
                      mutuallyConnectNewElement(data_point, cur_c, top_candidates, level);
                  }
  
  
              } else {
                  // Do nothing for the first element
                  enterpoint_node_ = 0;
                  maxlevel_ = curlevel;
  
              }
  
              //Releasing lock for the maximum level
              if (curlevel > maxlevelcopy) {
                  enterpoint_node_ = cur_c;
                  maxlevel_ = curlevel;
              }
              return cur_c;
          };
  
          std::priority_queue<std::pair<dist_t, labeltype >> searchKnn(const void *query_data, size_t k) const {
              tableint currObj = enterpoint_node_;
              dist_t curdist = fstdistfunc_(query_data, getDataByInternalId(enterpoint_node_), dist_func_param_);
  
              for (int level = maxlevel_; level > 0; level--) {
                  bool changed = true;
                  while (changed) {
                      changed = false;
                      int *data;
                      data = (int *) (linkLists_[currObj] + (level - 1) * size_links_per_element_);
                      int size = *data;
                      tableint *datal = (tableint *) (data + 1);
                      for (int i = 0; i < size; i++) {
                          tableint cand = datal[i];
                          if (cand < 0 || cand > max_elements_)
                              throw std::runtime_error("cand error");
                          dist_t d = fstdistfunc_(query_data, getDataByInternalId(cand), dist_func_param_);
  
                          if (d < curdist) {
                              curdist = d;
                              currObj = cand;
                              changed = true;
                          }
                      }
                  }
              }
  
  
              std::priority_queue<std::pair<dist_t, tableint>, std::vector<std::pair<dist_t, tableint>>, CompareByFirst> top_candidates = searchBaseLayerST(
                      currObj, query_data, std::max(ef_,k));
              std::priority_queue<std::pair<dist_t, labeltype >> results;
              while (top_candidates.size() > k) {
                  top_candidates.pop();
              }
              while (top_candidates.size() > 0) {
                  std::pair<dist_t, tableint> rez = top_candidates.top();
                  results.push(std::pair<dist_t, labeltype>(rez.first, getExternalLabel(rez.second)));
                  top_candidates.pop();
              }
              return results;
          };
  
  
      };
  
  }
  