bool EdgeIter::first_src()

in cpp/src/graphar/high-level/graph_reader.cc [710:823]

• 108 lines of code
• 28 McCabe index (conditional complexity)

bool EdgeIter::first_src(const EdgeIter& from, IdType id) {
  if (from.is_end())
    return false;

  // ordered_by_dest or unordered_by_dest
  if (adj_list_type_ == AdjListType::ordered_by_dest ||
      adj_list_type_ == AdjListType::unordered_by_dest) {
    if (from.global_chunk_index_ >= chunk_end_) {
      return false;
    }
    if (from.global_chunk_index_ == global_chunk_index_) {
      cur_offset_ = from.cur_offset_;
    } else if (from.global_chunk_index_ < chunk_begin_) {
      this->to_begin();
    } else {
      global_chunk_index_ = from.global_chunk_index_;
      cur_offset_ = from.cur_offset_;
      vertex_chunk_index_ = from.vertex_chunk_index_;
      this->refresh();
    }
    while (!this->is_end()) {
      if (this->source() == id)
        return true;
      this->operator++();
    }
    return false;
  }

  // unordered_by_source
  if (adj_list_type_ == AdjListType::unordered_by_source) {
    IdType expect_chunk_index =
        index_converter_->IndexPairToGlobalChunkIndex(id / src_chunk_size_, 0);
    if (expect_chunk_index > chunk_end_)
      return false;
    if (from.global_chunk_index_ >= chunk_end_) {
      return false;
    }
    bool need_refresh = false;
    if (from.global_chunk_index_ == global_chunk_index_) {
      cur_offset_ = from.cur_offset_;
    } else if (from.global_chunk_index_ < chunk_begin_) {
      this->to_begin();
    } else {
      global_chunk_index_ = from.global_chunk_index_;
      cur_offset_ = from.cur_offset_;
      vertex_chunk_index_ = from.vertex_chunk_index_;
      need_refresh = true;
    }
    if (global_chunk_index_ < expect_chunk_index) {
      global_chunk_index_ = expect_chunk_index;
      cur_offset_ = 0;
      vertex_chunk_index_ = id / src_chunk_size_;
      need_refresh = true;
    }
    if (need_refresh)
      this->refresh();
    while (!this->is_end()) {
      if (this->source() == id)
        return true;
      if (vertex_chunk_index_ > id / src_chunk_size_)
        return false;
      this->operator++();
    }
    return false;
  }

  // ordered_by_source
  auto st = offset_reader_->seek(id);
  if (!st.ok()) {
    return false;
  }
  auto maybe_offset_chunk = offset_reader_->GetChunk();
  if (!maybe_offset_chunk.status().ok()) {
    return false;
  }
  auto offset_array =
      std::dynamic_pointer_cast<arrow::Int64Array>(maybe_offset_chunk.value());
  auto begin_offset = static_cast<IdType>(offset_array->Value(0));
  auto end_offset = static_cast<IdType>(offset_array->Value(1));
  if (begin_offset >= end_offset) {
    return false;
  }
  auto vertex_chunk_index_of_id = offset_reader_->GetChunkIndex();
  auto begin_global_index = index_converter_->IndexPairToGlobalChunkIndex(
      vertex_chunk_index_of_id, begin_offset / chunk_size_);
  auto end_global_index = index_converter_->IndexPairToGlobalChunkIndex(
      vertex_chunk_index_of_id, end_offset / chunk_size_);
  if (begin_global_index <= from.global_chunk_index_ &&
      from.global_chunk_index_ <= end_global_index) {
    if (begin_offset < from.cur_offset_ && from.cur_offset_ < end_offset) {
      global_chunk_index_ = from.global_chunk_index_;
      cur_offset_ = from.cur_offset_;
      vertex_chunk_index_ = from.vertex_chunk_index_;
      refresh();
      return true;
    } else if (from.cur_offset_ <= begin_offset) {
      global_chunk_index_ = begin_global_index;
      cur_offset_ = begin_offset;
      vertex_chunk_index_ = vertex_chunk_index_of_id;
      refresh();
      return true;
    } else {
      return false;
    }
  } else if (from.global_chunk_index_ < begin_global_index) {
    global_chunk_index_ = begin_global_index;
    cur_offset_ = begin_offset;
    vertex_chunk_index_ = vertex_chunk_index_of_id;
    refresh();
    return true;
  } else {
    return false;
  }
}