susumu.yata
null+****@clear*****
Tue Sep 16 10:14:52 JST 2014
susumu.yata 2014-09-16 10:14:52 +0900 (Tue, 16 Sep 2014) New Revision: e2c7f252694274a303ee7b4cf358404a95c6d630 https://github.com/groonga/grnxx/commit/e2c7f252694274a303ee7b4cf358404a95c6d630 Message: Support offset and limit for Cursor. Modified files: lib/grnxx/index.cpp Modified: lib/grnxx/index.cpp (+106 -94) =================================================================== --- lib/grnxx/index.cpp 2014-09-16 10:07:40 +0900 (6fbdd9a) +++ lib/grnxx/index.cpp 2014-09-16 10:14:52 +0900 (7b4cde7) @@ -148,14 +148,17 @@ template <typename T> Int IteratorCursor<T>::read(Error *error, Int max_count, Array<Record> *records) { + if (max_count > limit_left_) { + max_count = limit_left_; + } + if (max_count <= 0) { + return 0; + } + Int count = 0; while ((offset_left_ > 0) && (it_ != end_)) { ++it_; --offset_left_; } - Int count = 0; - if (max_count > limit_left_) { - max_count = limit_left_; - } while ((count < max_count) && (it_ != end_)) { if (!records->push_back(error, Record(*it_, 0.0))) { return -1; @@ -209,49 +212,63 @@ unique_ptr<Cursor> create_reverse_iterator_cursor(Error *error, return cursor; } -// -- TreeIndexRegularCursor -- - -template <typename T> class TreeIndexRegularCursor; +// -- DualIteratorCursor -- -template <> -class TreeIndexRegularCursor<Int> : public Cursor { +template <typename T> +class MapSetCursor : public Cursor { public: - using Value = Int; - using Set = std::set<Int>; - using Map = std::map<Value, Set>; - - TreeIndexRegularCursor(const Table *table, - Map::iterator begin, - Map::iterator end) + using MapIterator = T; + using SetIterator = typename MapIterator::value_type::second_type::iterator; + + MapSetCursor(const Table *table, + MapIterator begin, + MapIterator end, + Int offset, + Int limit) : Cursor(table), + map_begin_(begin), map_it_(begin), map_end_(end), set_it_(), - set_end_() { - if (begin != end) { + set_end_(), + offset_(offset), + limit_(limit), + offset_left_(offset), + limit_left_(limit) { + if (map_it_ != map_end_) { set_it_ = map_it_->second.begin(); set_end_ = map_it_->second.end(); } } - ~TreeIndexRegularCursor() {} + ~MapSetCursor() {} Int read(Error *error, Int max_count, Array<Record> *records); private: - Map::iterator map_it_; - Map::iterator map_end_; - Set::iterator set_it_; - Set::iterator set_end_; + MapIterator map_begin_; + MapIterator map_it_; + MapIterator map_end_; + SetIterator set_begin_; + SetIterator set_it_; + SetIterator set_end_; + Int offset_; + Int limit_; + Int offset_left_; + Int limit_left_; }; -Int TreeIndexRegularCursor<Int>::read(Error *error, - Int max_count, - Array<Record> *records) { - if (map_it_ == map_end_) { +template <typename T> +Int MapSetCursor<T>::read(Error *error, + Int max_count, + Array<Record> *records) { + if (max_count > limit_left_) { + max_count = limit_left_; + } + if (max_count <= 0) { return 0; } Int count = 0; - for ( ; count < max_count; ++count) { + while ((count < max_count) && (map_it_ != map_end_)) { if (set_it_ == set_end_) { ++map_it_; if (map_it_ == map_end_) { @@ -259,72 +276,65 @@ Int TreeIndexRegularCursor<Int>::read(Error *error, } set_it_ = map_it_->second.begin(); set_end_ = map_it_->second.end(); + if (set_it_ == set_end_) { + continue; + } } - if (!records->push_back(error, Record(*set_it_, 0.0))) { - return -1; + + if (offset_left_ > 0) { + --offset_left_; + } else { + if (!records->push_back(error, Record(*set_it_, 0.0))) { + return -1; + } + ++count; } ++set_it_; } + limit_left_ -= count; return count; } -// -- TreeIndexReverseCursor -- - -template <typename T> class TreeIndexReverseCursor; - -template <> -class TreeIndexReverseCursor<Int> : public Cursor { - public: - using Value = Int; - using Set = std::set<Int>; - using Map = std::map<Value, Set>; - - TreeIndexReverseCursor(const Table *table, - Map::iterator begin, - Map::iterator end) - : Cursor(table), - map_it_(Map::reverse_iterator(end)), - map_end_(Map::reverse_iterator(begin)), - set_it_(), - set_end_() { - if (begin != end) { - set_it_ = map_it_->second.begin(); - set_end_ = map_it_->second.end(); - } +// Helper function to create a map set cursor. +template <typename T> +unique_ptr<Cursor> create_map_set_cursor(Error *error, + const Table *table, + T begin, + T end, + Int offset, + Int limit) { + unique_ptr<Cursor> cursor( + new (nothrow) MapSetCursor<T>(table, begin, end, offset, limit)); + if (!cursor) { + GRNXX_ERROR_SET(error, NO_MEMORY, "Memory allocation failed"); + return nullptr; } - ~TreeIndexReverseCursor() {} - - Int read(Error *error, Int max_count, Array<Record> *records); - - private: - Map::reverse_iterator map_it_; - Map::reverse_iterator map_end_; - Set::iterator set_it_; - Set::iterator set_end_; -}; + return cursor; +} -Int TreeIndexReverseCursor<Int>::read(Error *error, - Int max_count, - Array<Record> *records) { - if (map_it_ == map_end_) { - return 0; - } - Int count = 0; - for ( ; count < max_count; ++count) { - 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 (!records->push_back(error, Record(*set_it_, 0.0))) { - return -1; - } - ++set_it_; +// TODO: It's not clear that a reverse cursor should return row IDs in +// reverse order or not. +// +// Helper function to create a reverse map set cursor. +template <typename T> +unique_ptr<Cursor> create_reverse_map_set_cursor(Error *error, + const Table *table, + T begin, + T end, + Int offset, + Int limit) { + using ReverseIterator = std::reverse_iterator<T>; + unique_ptr<Cursor> cursor( + new (nothrow) MapSetCursor<ReverseIterator>(table, + ReverseIterator(end), + ReverseIterator(begin), + offset, + limit)); + if (!cursor) { + GRNXX_ERROR_SET(error, NO_MEMORY, "Memory allocation failed"); + return nullptr; } - return count; + return cursor; } // -- TreeIndex<Int> -- @@ -446,19 +456,21 @@ unique_ptr<Cursor> TreeIndex<Int>::create_cursor( auto begin = map_.lower_bound(lower_bound_value); auto end = map_.upper_bound(upper_bound_value); - unique_ptr<Cursor> cursor; if (options.order_type == REGULAR_ORDER) { - cursor.reset(new (nothrow) TreeIndexRegularCursor<Int>( - column_->table(), begin, end)); + return create_map_set_cursor(error, + column_->table(), + begin, + end, + options.offset, + options.limit); } else { - cursor.reset(new (nothrow) TreeIndexReverseCursor<Int>( - column_->table(), begin, end)); + return create_reverse_map_set_cursor(error, + column_->table(), + begin, + end, + options.offset, + options.limit); } - if (!cursor) { - GRNXX_ERROR_SET(error, NO_MEMORY, "Memory allocation failed"); - return nullptr; - } - return cursor; } bool TreeIndex<Int>::insert(Error *, Int row_id, const Datum &value) { -------------- next part -------------- HTML����������������������������...Descargar
