Method gen_match_hfa

lib/pattern.cpp:4663–4685

}

void Pattern::gen_match_hfa(DFA::State *start)
{
  size_t max_level = HFA::MAX_DEPTH - 1; // max level from start state(s) is reduced when hashes exponentially increase
  HFA::State index = 1; // DFA states are enumarated for breadth-first matching with the state visit set in match_hfa()
  HFA::StateHashes hashes[HFA::MAX_DEPTH]; // up to MAX_DEPTH states deep into the DFA are hashed from the start state(s)
  gen_match_hfa_start(start, index, hashes[0]);
  for (size_t level = 1; level <= max_level; ++level)
    for (HFA::StateHashes::iterator from = hashes[level - 1].begin(); from != hashes[level - 1].end(); ++from)
      if (!gen_match_hfa_transitions(level, max_level, from->first, from->second, index, hashes[level]))
        break;
  // move the HFA to a new HFA with enumerated states for breadth-first matching with a bitset in match_hfa()
  for (size_t level = 0; level <= max_level; ++level)
  {
    HFA::StateHashes::iterator hashes_end = hashes[level].end();
    for (HFA::StateHashes::iterator next = hashes[level].begin(); next != hashes_end; ++next)
    {
      HFA::HashRanges& set_ranges = hfa_.hashes[level][next->first->index];
      HFA::HashRanges& get_ranges = next->second;
      for (size_t offset = std::max<size_t>(HFA::MAX_CHAIN - 1, level) + 1 - HFA::MAX_CHAIN; offset <= level; ++offset)
        set_ranges[offset].swap(get_ranges[offset]);
    }
  }
}

void Pattern::gen_match_hfa_start(DFA::State *start, HFA::State& index, HFA::StateHashes& hashes)
{