susumu.yata
null+****@clear*****
Tue Dec 2 10:06:55 JST 2014
susumu.yata 2014-12-02 10:06:55 +0900 (Tue, 02 Dec 2014) New Revision: 6a2cef3ff2ad1a34d2419bb6937a3d81e0832f0a https://github.com/groonga/grnxx/commit/6a2cef3ff2ad1a34d2419bb6937a3d81e0832f0a Message: Add RangeCursor for find_in_range(). (#124) Modified files: lib/grnxx/impl/index.cpp Modified: lib/grnxx/impl/index.cpp (+100 -0) =================================================================== --- lib/grnxx/impl/index.cpp 2014-12-02 10:05:55 +0900 (90f8035) +++ lib/grnxx/impl/index.cpp 2014-12-02 10:06:55 +0900 (89e82b4) @@ -86,6 +86,106 @@ std::unique_ptr<Cursor> create_reverse_exact_match_cursor(T begin, limit)); } +// -- ExactMatchCursor -- + +template <typename T> +class RangeCursor : public Cursor { + public: + using MapIterator = T; + using SetIterator = typename MapIterator::value_type::second_type::iterator; + + RangeCursor(MapIterator begin, + MapIterator end, + size_t offset, + size_t limit) + : Cursor(), + map_it_(begin), + map_end_(end), + set_it_(), + set_end_(), + offset_(offset), + limit_(limit) { + if (map_it_ != map_end_) { + set_it_ = map_it_->second.begin(); + set_end_ = map_it_->second.end(); + } + } + ~RangeCursor() = default; + + size_t read(ArrayRef<Record> records); + + private: + MapIterator map_it_; + MapIterator map_end_; + SetIterator set_it_; + SetIterator set_end_; + size_t offset_; + size_t limit_; +}; + +template <typename T> +size_t RangeCursor<T>::read(ArrayRef<Record> records) { + size_t max_count = records.size(); + if (max_count > limit_) { + max_count = limit_; + } + if (max_count <= 0) { + return 0; + } + size_t count = 0; + while ((count < max_count) && (map_it_ != map_end_)) { + if (set_it_ == set_end_) { + ++map_it_; + if (map_it_ == map_end_) { + break; + } + set_it_ = map_it_->second.begin(); + set_end_ = map_it_->second.end(); + if (set_it_ == set_end_) { + continue; + } + } + if (offset_ > 0) { + --offset_; + } else { + records[count] = Record(*set_it_, Float(0.0)); + ++count; + } + ++set_it_; + } + limit_ -= count; + return count; +} + +// Helper function to create a range cursor. +template <typename T> +std::unique_ptr<Cursor> create_range_cursor(T begin, + T end, + size_t offset, + size_t limit) { + return std::unique_ptr<Cursor>( + new RangeCursor<T>(begin, end, offset, limit)); +} + +// TODO: It's not clear that a reverse cursor should return row IDs in +// reverse order or not. +// +// Helper function to create a reverse range cursor. +template <typename T> +std::unique_ptr<Cursor> create_reverse_range_cursor(T begin, + T end, + size_t offset, + size_t limit) { + using ReverseIterator = std::reverse_iterator<T>; + return std::unique_ptr<Cursor>( + new RangeCursor<ReverseIterator>(ReverseIterator(end), + ReverseIterator(begin), + offset, + limit)); +} + +// -- TreeIndex -- + template <typename T> class TreeIndex; template <> -------------- next part -------------- HTML����������������������������...Download
