26     indices_.reserve(keys_.size());  in VectorIterator()
28       indices_.push_back(i);  in VectorIterator()
30     std::sort(indices_.begin(), indices_.end(), indexed_cmp_);  in VectorIterator()
34     return !indices_.empty() && current_ < indices_.size();  in Valid()
38   virtual void SeekToLast() override { current_ = indices_.size() - 1; }  in SeekToLast()
41     current_ = std::lower_bound(indices_.begin(), indices_.end(), target,  in Seek()
43                indices_.begin();  in Seek()
47     current_ = std::lower_bound(indices_.begin(), indices_.end(), target,  in SeekForPrev()
49                indices_.begin();  in SeekForPrev()
61     return Slice(keys_[indices_[current_]]);  in key()
64     return Slice(values_[indices_[current_]]);  in value()
97   std::vector<size_t> indices_;  variable