https://github.com/facebook/rocksdb
Tip revision: 6cc72412068595b9f308e5246cae0d96a5cae4d2 authored by Dhruba Borthakur on 13 March 2013, 22:38:02 UTC
Release 1.5.8.fb.
Release 1.5.8.fb.
Tip revision: 6cc7241
iter_heap.h
// Copyright 2008-present Facebook. All Rights Reserved.
#ifndef STORAGE_LEVELDB_ITER_HEAP_H_
#define STORAGE_LEVELDB_ITER_HEAP_H_
#include <queue>
#include "leveldb/comparator.h"
#include "table/iterator_wrapper.h"
namespace leveldb {
// 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 leveldb
#endif // STORAGE_LEVELDB_ITER_HEAP_H_