diff options
Diffstat (limited to 'src/leveldb/table/merger.cc')
-rw-r--r-- | src/leveldb/table/merger.cc | 52 |
1 files changed, 23 insertions, 29 deletions
diff --git a/src/leveldb/table/merger.cc b/src/leveldb/table/merger.cc index 2dde4dc21f..76441b1cc2 100644 --- a/src/leveldb/table/merger.cc +++ b/src/leveldb/table/merger.cc @@ -17,22 +17,18 @@ class MergingIterator : public Iterator { : comparator_(comparator), children_(new IteratorWrapper[n]), n_(n), - current_(NULL), + current_(nullptr), direction_(kForward) { for (int i = 0; i < n; i++) { children_[i].Set(children[i]); } } - virtual ~MergingIterator() { - delete[] children_; - } + ~MergingIterator() override { delete[] children_; } - virtual bool Valid() const { - return (current_ != NULL); - } + bool Valid() const override { return (current_ != nullptr); } - virtual void SeekToFirst() { + void SeekToFirst() override { for (int i = 0; i < n_; i++) { children_[i].SeekToFirst(); } @@ -40,7 +36,7 @@ class MergingIterator : public Iterator { direction_ = kForward; } - virtual void SeekToLast() { + void SeekToLast() override { for (int i = 0; i < n_; i++) { children_[i].SeekToLast(); } @@ -48,7 +44,7 @@ class MergingIterator : public Iterator { direction_ = kReverse; } - virtual void Seek(const Slice& target) { + void Seek(const Slice& target) override { for (int i = 0; i < n_; i++) { children_[i].Seek(target); } @@ -56,7 +52,7 @@ class MergingIterator : public Iterator { direction_ = kForward; } - virtual void Next() { + void Next() override { assert(Valid()); // Ensure that all children are positioned after key(). @@ -82,7 +78,7 @@ class MergingIterator : public Iterator { FindSmallest(); } - virtual void Prev() { + void Prev() override { assert(Valid()); // Ensure that all children are positioned before key(). @@ -111,17 +107,17 @@ class MergingIterator : public Iterator { FindLargest(); } - virtual Slice key() const { + Slice key() const override { assert(Valid()); return current_->key(); } - virtual Slice value() const { + Slice value() const override { assert(Valid()); return current_->value(); } - virtual Status status() const { + Status status() const override { Status status; for (int i = 0; i < n_; i++) { status = children_[i].status(); @@ -133,6 +129,9 @@ class MergingIterator : public Iterator { } private: + // Which direction is the iterator moving? + enum Direction { kForward, kReverse }; + void FindSmallest(); void FindLargest(); @@ -143,21 +142,15 @@ class MergingIterator : public Iterator { IteratorWrapper* children_; int n_; IteratorWrapper* current_; - - // Which direction is the iterator moving? - enum Direction { - kForward, - kReverse - }; Direction direction_; }; void MergingIterator::FindSmallest() { - IteratorWrapper* smallest = NULL; + IteratorWrapper* smallest = nullptr; for (int i = 0; i < n_; i++) { IteratorWrapper* child = &children_[i]; if (child->Valid()) { - if (smallest == NULL) { + if (smallest == nullptr) { smallest = child; } else if (comparator_->Compare(child->key(), smallest->key()) < 0) { smallest = child; @@ -168,11 +161,11 @@ void MergingIterator::FindSmallest() { } void MergingIterator::FindLargest() { - IteratorWrapper* largest = NULL; - for (int i = n_-1; i >= 0; i--) { + IteratorWrapper* largest = nullptr; + for (int i = n_ - 1; i >= 0; i--) { IteratorWrapper* child = &children_[i]; if (child->Valid()) { - if (largest == NULL) { + if (largest == nullptr) { largest = child; } else if (comparator_->Compare(child->key(), largest->key()) > 0) { largest = child; @@ -183,14 +176,15 @@ void MergingIterator::FindLargest() { } } // namespace -Iterator* NewMergingIterator(const Comparator* cmp, Iterator** list, int n) { +Iterator* NewMergingIterator(const Comparator* comparator, Iterator** children, + int n) { assert(n >= 0); if (n == 0) { return NewEmptyIterator(); } else if (n == 1) { - return list[0]; + return children[0]; } else { - return new MergingIterator(cmp, list, n); + return new MergingIterator(comparator, children, n); } } |