ef5b384729
1, const qualifiers on return types make no sense and will trigger a compile warning: warning: type qualifiers ignored on function return type [-Wignored-qualifiers] 2, class HistogramImpl has virtual functions and thus should have a virtual destructor 3, with some toolchain, the macro __STDC_FORMAT_MACROS is predefined and thus should be checked before define Change-Id: I69747a03bfae88671bfbb2637c80d17600159c99 Signed-off-by: liuhuahang <liuhuahang@zerus.co>
82 lines
2.2 KiB
C++
82 lines
2.2 KiB
C++
// Copyright (c) 2013, Facebook, Inc. All rights reserved.
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// This source code is licensed under the BSD-style license found in the
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// LICENSE file in the root directory of this source tree. An additional grant
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// of patent rights can be found in the PATENTS file in the same directory.
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//
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// Copyright (c) 2011 The LevelDB Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file. See the AUTHORS file for names of contributors.
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#pragma once
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#include "rocksdb/statistics.h"
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#include <cassert>
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#include <string>
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#include <vector>
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#include <map>
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namespace rocksdb {
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class HistogramBucketMapper {
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public:
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HistogramBucketMapper();
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// converts a value to the bucket index.
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size_t IndexForValue(const uint64_t value) const;
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// number of buckets required.
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size_t BucketCount() const {
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return bucketValues_.size();
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}
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uint64_t LastValue() const {
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return maxBucketValue_;
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}
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uint64_t FirstValue() const {
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return minBucketValue_;
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}
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uint64_t BucketLimit(const uint64_t bucketNumber) const {
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assert(bucketNumber < BucketCount());
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return bucketValues_[bucketNumber];
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}
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private:
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const std::vector<uint64_t> bucketValues_;
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const uint64_t maxBucketValue_;
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const uint64_t minBucketValue_;
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std::map<uint64_t, uint64_t> valueIndexMap_;
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};
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class HistogramImpl {
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public:
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virtual void Clear();
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virtual bool Empty();
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virtual void Add(uint64_t value);
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void Merge(const HistogramImpl& other);
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virtual std::string ToString() const;
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virtual double Median() const;
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virtual double Percentile(double p) const;
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virtual double Average() const;
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virtual double StandardDeviation() const;
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virtual void Data(HistogramData * const data) const;
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virtual ~HistogramImpl() {}
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private:
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// To be able to use HistogramImpl as thread local variable, its constructor
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// has to be static. That's why we're using manually values from BucketMapper
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double min_ = 1000000000; // this is BucketMapper:LastValue()
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double max_ = 0;
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double num_ = 0;
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double sum_ = 0;
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double sum_squares_ = 0;
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uint64_t buckets_[138] = {0}; // this is BucketMapper::BucketCount()
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};
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} // namespace rocksdb
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