rocksdb/table/iter_heap.h
Dhruba Borthakur 9cd221094c Add appropriate LICENSE and Copyright message.
Summary:
Add appropriate LICENSE and Copyright message.

Test Plan:
make check

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Blame Rev:
2013-10-16 17:48:41 -07:00

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1.9 KiB
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// Copyright (c) 2013, Facebook, Inc. All rights reserved.
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree. An additional grant
// of patent rights can be found in the PATENTS file in the same directory.
//
#pragma once
#include <queue>
#include "rocksdb/comparator.h"
#include "table/iterator_wrapper.h"
namespace rocksdb {
// Return the max of two keys.
class MaxIteratorComparator {
public:
MaxIteratorComparator(const Comparator* comparator) :
comparator_(comparator) {}
bool operator()(IteratorWrapper* a, IteratorWrapper* b) {
return comparator_->Compare(a->key(), b->key()) <= 0;
}
private:
const Comparator* comparator_;
};
// Return the max of two keys.
class MinIteratorComparator {
public:
// if maxHeap is set comparator returns the max value.
// else returns the min Value.
// Can use to create a minHeap or a maxHeap.
MinIteratorComparator(const Comparator* comparator) :
comparator_(comparator) {}
bool operator()(IteratorWrapper* a, IteratorWrapper* b) {
return comparator_->Compare(a->key(), b->key()) > 0;
}
private:
const Comparator* comparator_;
};
typedef std::priority_queue<
IteratorWrapper*,
std::vector<IteratorWrapper*>,
MaxIteratorComparator> MaxIterHeap;
typedef std::priority_queue<
IteratorWrapper*,
std::vector<IteratorWrapper*>,
MinIteratorComparator> MinIterHeap;
// Return's a new MaxHeap of IteratorWrapper's using the provided Comparator.
MaxIterHeap NewMaxIterHeap(const Comparator* comparator) {
return MaxIterHeap(MaxIteratorComparator(comparator));
}
// Return's a new MinHeap of IteratorWrapper's using the provided Comparator.
MinIterHeap NewMinIterHeap(const Comparator* comparator) {
return MinIterHeap(MinIteratorComparator(comparator));
}
} // namespace rocksdb