1 /* 2 * Copyright (C) 2024 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include <android/util/ProtoOutputStream.h> 18 19 #include <string> 20 #include <vector> 21 22 #include "stats_util.h" 23 24 #pragma once 25 26 namespace android { 27 namespace os { 28 namespace statsd { 29 30 size_t getCompactedBinCountsSize(const std::vector<int>& binCounts); 31 32 // Encapsulates histogram bin counts. This class is not thread-safe. 33 class HistogramValue { 34 public: 35 // Default constructor 36 constexpr HistogramValue() noexcept = default; 37 38 // Copy constructor for pre-aggregated bin counts. HistogramValue(const std::vector<int> & binCounts)39 constexpr HistogramValue(const std::vector<int>& binCounts) : mBinCounts(binCounts) { 40 } 41 42 // Move constructor for pre-aggregated bin counts. HistogramValue(std::vector<int> && binCounts)43 constexpr HistogramValue(std::vector<int>&& binCounts) : mBinCounts(std::move(binCounts)) { 44 } 45 46 std::string toString() const; 47 48 bool isEmpty() const; 49 50 size_t getSize() const; 51 52 // Should only be called on HistogramValue instances returned by getCompactedHistogramValue(). 53 // Also, this should be called to dump histogram data to proto. 54 void toProto(android::util::ProtoOutputStream& protoOutput) const; 55 56 void addValue(float value, const BinStarts& binStarts); 57 58 // Returns a new HistogramValue where mBinCounts is compressed as follows: 59 // For each entry in mBinCounts, n: 60 // * n >= 0 represents the actual count 61 // * n == -1 does not appear 62 // * n <= -2 represents -n consecutive bins with count of 0 63 // Called on bucket flushes from NumericValueMetricProducer 64 HistogramValue getCompactedHistogramValue() const; 65 66 bool isValid() const; 67 68 HistogramValue& operator+=(const HistogramValue& rhs); 69 70 // Returns a HistogramValue where each bin is the sum of the corresponding bins in lhs and rhs. 71 // If rhs has fewer bins, the remaining lhs bins are copied to the returned HistogramValue. 72 friend HistogramValue operator+(HistogramValue lhs, const HistogramValue& rhs); 73 74 HistogramValue& operator-=(const HistogramValue& rhs); 75 76 // Returns a HistogramValue where each bin in rhs is subtracted from the corresponding bin in 77 // lhs. If rhs has fewer bins, the remaining lhs bins are copied to the returned HistogramValue. 78 // For bins where the returned value would be less than 0, their values are set to 0 instead. 79 friend HistogramValue operator-(HistogramValue lhs, const HistogramValue& rhs); 80 81 friend bool operator==(const HistogramValue& lhs, const HistogramValue& rhs); 82 83 friend bool operator!=(const HistogramValue& lhs, const HistogramValue& rhs); 84 85 friend bool operator<(const HistogramValue& lhs, const HistogramValue& rhs); 86 87 friend bool operator>(const HistogramValue& lhs, const HistogramValue& rhs); 88 89 friend bool operator<=(const HistogramValue& lhs, const HistogramValue& rhs); 90 91 friend bool operator>=(const HistogramValue& lhs, const HistogramValue& rhs); 92 93 // Error states encountered during binary operations. 94 static const HistogramValue ERROR_BINS_MISMATCH; 95 static const HistogramValue ERROR_BIN_COUNT_TOO_HIGH; 96 97 private: 98 std::vector<int> mBinCounts; 99 bool mCompacted = false; 100 }; 101 102 } // namespace statsd 103 } // namespace os 104 } // namespace android 105