Class BaseIterator

Bcore/src/main/cpp/base/hash_set.h:67–120

class HashSet {
  template <class Elem, class HashSetType>
  class BaseIterator : std::iterator<std::forward_iterator_tag, Elem> {
   public:
    BaseIterator(const BaseIterator&) = default;
    BaseIterator(BaseIterator&&) = default;
    BaseIterator(HashSetType* hash_set, size_t index) : index_(index), hash_set_(hash_set) {
    }
    BaseIterator& operator=(const BaseIterator&) = default;
    BaseIterator& operator=(BaseIterator&&) = default;

    bool operator==(const BaseIterator& other) const {
      return hash_set_ == other.hash_set_ && this->index_ == other.index_;
    }

    bool operator!=(const BaseIterator& other) const {
      return !(*this == other);
    }

    BaseIterator operator++() {  // Value after modification.
      this->index_ = this->NextNonEmptySlot(this->index_, hash_set_);
      return *this;
    }

    BaseIterator operator++(int) {
      BaseIterator temp = *this;
      this->index_ = this->NextNonEmptySlot(this->index_, hash_set_);
      return temp;
    }

    Elem& operator*() const {
      DCHECK(!hash_set_->IsFreeSlot(this->index_));
      return hash_set_->ElementForIndex(this->index_);
    }

    Elem* operator->() const {
      return &**this;
    }

    // TODO: Operator -- --(int)  (and use std::bidirectional_iterator_tag)

   private:
    size_t index_;
    HashSetType* hash_set_;

    size_t NextNonEmptySlot(size_t index, const HashSet* hash_set) const {
      const size_t num_buckets = hash_set->NumBuckets();
      DCHECK_LT(index, num_buckets);
      do {
        ++index;
      } while (index < num_buckets && hash_set->IsFreeSlot(index));
      return index;
    }

    friend class HashSet;
  };

 public:
  using value_type = T;