libs/battery/MultiStateCounter.h - platform/frameworks/native - Gitiles

 /*
  * Copyright (C) 2021 The Android Open Source Project
  * Android BPF library - public API
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *      http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 #pragma once

 #include <inttypes.h>
 #include <log/log.h>
 #include <time.h>
 #include <sstream>
 #include <string>

 /**
  * An object that can track changes of some value over time, taking into account an additional
  * dimension: the object's state.  As the tracked value changes, the deltas are distributed
  * among the object states in accordance with the time spent in those states.
  */
 namespace android {
 namespace battery {

 typedef uint16_t state_t;

 template <class T>
 class MultiStateCounter {
     uint16_t stateCount;
     state_t currentState;
     time_t lastStateChangeTimestamp;
     T emptyValue;
     T lastValue;
     time_t lastUpdateTimestamp;
     T deltaValue;
     bool isEnabled;

     struct State {
         time_t timeInStateSinceUpdate;
         T counter;
     };

     State* states;

 public:
     MultiStateCounter(uint16_t stateCount, const T& emptyValue);

     virtual ~MultiStateCounter();

     void setEnabled(bool enabled, time_t timestamp);

     void setState(state_t state, time_t timestamp);

     void setValue(state_t state, const T& value);

     /**
      * Updates the value by distributing the delta from the previously set value
      * among states according to their respective time-in-state.
      * Returns the delta from the previously set value.
      */
     const T& updateValue(const T& value, time_t timestamp);

     /**
      * Updates the value by distributing the specified increment among states according
      * to their respective time-in-state.
      */
     void incrementValue(const T& increment, time_t timestamp);

     /**
      * Adds the specified increment to the value for the current state, without affecting
      * the last updated value or timestamp.  Ignores partial time-in-state: the entirety of
      * the increment is given to the current state.
      */
     void addValue(const T& increment);

     void reset();

     uint16_t getStateCount();

     const T& getCount(state_t state);

     std::string toString();

 private:
     /**
      * Subtracts previousValue from newValue and returns the result in outValue.
      * Returns true iff the combination of previousValue and newValue is valid
      * (newValue >= prevValue)
      */
     bool delta(const T& previousValue, const T& newValue, T* outValue) const;

     /**
      * Adds value2 to value1 and stores the result in value1.  Denominator is
      * guaranteed to be non-zero.
      */
     void add(T* value1, const T& value2, const uint64_t numerator,
              const uint64_t denominator) const;

     std::string valueToString(const T& value) const;
 };

 // ---------------------- MultiStateCounter Implementation -------------------------
 // Since MultiStateCounter is a template, the implementation must be inlined.

 template <class T>
 MultiStateCounter<T>::MultiStateCounter(uint16_t stateCount, const T& emptyValue)
       : stateCount(stateCount),
         currentState(0),
         lastStateChangeTimestamp(-1),
         emptyValue(emptyValue),
         lastValue(emptyValue),
         lastUpdateTimestamp(-1),
         deltaValue(emptyValue),
         isEnabled(true) {
     states = new State[stateCount];
     for (int i = 0; i < stateCount; i++) {
         states[i].timeInStateSinceUpdate = 0;
         states[i].counter = emptyValue;
     }
 }

 template <class T>
 MultiStateCounter<T>::~MultiStateCounter() {
     delete[] states;
 };

 template <class T>
 void MultiStateCounter<T>::setEnabled(bool enabled, time_t timestamp) {
     if (enabled == isEnabled) {
         return;
     }

     if (!enabled) {
         // Confirm the current state for the side-effect of updating the time-in-state
         // counter for the current state.
         setState(currentState, timestamp);
     }

     isEnabled = enabled;

     if (lastStateChangeTimestamp >= 0) {
         lastStateChangeTimestamp = timestamp;
     }
 }

 template <class T>
 void MultiStateCounter<T>::setState(state_t state, time_t timestamp) {
     if (isEnabled && lastStateChangeTimestamp >= 0) {
         if (timestamp >= lastStateChangeTimestamp) {
             states[currentState].timeInStateSinceUpdate += timestamp - lastStateChangeTimestamp;
         } else {
             ALOGE("setState is called with an earlier timestamp: %lu, previous timestamp: %lu\n",
                   (unsigned long)timestamp, (unsigned long)lastStateChangeTimestamp);
             // The accumulated durations have become unreliable. For example, if the timestamp
             // sequence was 1000, 2000, 1000, 3000, if we accumulated the positive deltas,
             // we would get 4000, which is greater than (last - first). This could lead to
             // counts exceeding 100%.
             for (int i = 0; i < stateCount; i++) {
                 states[i].timeInStateSinceUpdate = 0;
             }
         }
     }
     currentState = state;
     lastStateChangeTimestamp = timestamp;
 }

 template <class T>
 void MultiStateCounter<T>::setValue(state_t state, const T& value) {
     states[state].counter = value;
 }

 template <class T>
 const T& MultiStateCounter<T>::updateValue(const T& value, time_t timestamp) {
     T* returnValue = &emptyValue;

     // If the counter is disabled, we ignore the update, except when the counter got disabled after
     // the previous update, in which case we still need to pick up the residual delta.
     if (isEnabled || lastUpdateTimestamp < lastStateChangeTimestamp) {
         // Confirm the current state for the side-effect of updating the time-in-state
         // counter for the current state.
         setState(currentState, timestamp);

         if (lastUpdateTimestamp >= 0) {
             if (timestamp > lastUpdateTimestamp) {
                 if (delta(lastValue, value, &deltaValue)) {
                     returnValue = &deltaValue;
                     time_t timeSinceUpdate = timestamp - lastUpdateTimestamp;
                     for (int i = 0; i < stateCount; i++) {
                         time_t timeInState = states[i].timeInStateSinceUpdate;
                         if (timeInState) {
                             add(&states[i].counter, deltaValue, timeInState, timeSinceUpdate);
                             states[i].timeInStateSinceUpdate = 0;
                         }
                     }
                 } else {
                     std::stringstream str;
                     str << "updateValue is called with a value " << valueToString(value)
                         << ", which is lower than the previous value " << valueToString(lastValue)
                         << "\n";
                     ALOGE("%s", str.str().c_str());

                     for (int i = 0; i < stateCount; i++) {
                         states[i].timeInStateSinceUpdate = 0;
                     }
                 }
             } else if (timestamp < lastUpdateTimestamp) {
                 ALOGE("updateValue is called with an earlier timestamp: %lu, previous: %lu\n",
                       (unsigned long)timestamp, (unsigned long)lastUpdateTimestamp);

                 for (int i = 0; i < stateCount; i++) {
                     states[i].timeInStateSinceUpdate = 0;
                 }
             }
         }
     }
     lastValue = value;
     lastUpdateTimestamp = timestamp;
     return *returnValue;
 }

 template <class T>
 void MultiStateCounter<T>::incrementValue(const T& increment, time_t timestamp) {
     T newValue = lastValue;
     add(&newValue, increment, 1 /* numerator */, 1 /* denominator */);
     updateValue(newValue, timestamp);
 }

 template <class T>
 void MultiStateCounter<T>::addValue(const T& value) {
     if (!isEnabled) {
         return;
     }
     add(&states[currentState].counter, value, 1 /* numerator */, 1 /* denominator */);
 }

 template <class T>
 void MultiStateCounter<T>::reset() {
     lastStateChangeTimestamp = -1;
     lastUpdateTimestamp = -1;
     for (int i = 0; i < stateCount; i++) {
         states[i].timeInStateSinceUpdate = 0;
         states[i].counter = emptyValue;
     }
 }

 template <class T>
 uint16_t MultiStateCounter<T>::getStateCount() {
     return stateCount;
 }

 template <class T>
 const T& MultiStateCounter<T>::getCount(state_t state) {
     return states[state].counter;
 }

 template <class T>
 std::string MultiStateCounter<T>::toString() {
     std::stringstream str;
     str << "[";
     for (int i = 0; i < stateCount; i++) {
         if (i != 0) {
             str << ", ";
         }
         str << i << ": " << valueToString(states[i].counter);
         if (states[i].timeInStateSinceUpdate > 0) {
             str << " timeInStateSinceUpdate: " << states[i].timeInStateSinceUpdate;
         }
     }
     str << "]";
     if (lastUpdateTimestamp >= 0) {
         str << " updated: " << lastUpdateTimestamp;
     }
     if (lastStateChangeTimestamp >= 0) {
         str << " currentState: " << currentState;
         if (lastStateChangeTimestamp > lastUpdateTimestamp) {
             str << " stateChanged: " << lastStateChangeTimestamp;
         }
     } else {
         str << " currentState: none";
     }
     if (!isEnabled) {
         str << " disabled";
     }
     return str.str();
 }

 } // namespace battery
 } // namespace android
	/*
	* Copyright (C) 2021 The Android Open Source Project
	* Android BPF library - public API
	*
	* Licensed under the Apache License, Version 2.0 (the "License");
	* you may not use this file except in compliance with the License.
	* You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	#pragma once

	#include <inttypes.h>
	#include <log/log.h>
	#include <time.h>
	#include <sstream>
	#include <string>

	/**
	* An object that can track changes of some value over time, taking into account an additional
	* dimension: the object's state. As the tracked value changes, the deltas are distributed
	* among the object states in accordance with the time spent in those states.
	*/
	namespace android {
	namespace battery {

	typedef uint16_t state_t;

	template <class T>
	class MultiStateCounter {
	uint16_t stateCount;
	state_t currentState;
	time_t lastStateChangeTimestamp;
	T emptyValue;
	T lastValue;
	time_t lastUpdateTimestamp;
	T deltaValue;
	bool isEnabled;

	struct State {
	time_t timeInStateSinceUpdate;
	T counter;
	};

	State* states;

	public:
	MultiStateCounter(uint16_t stateCount, const T& emptyValue);

	virtual ~MultiStateCounter();

	void setEnabled(bool enabled, time_t timestamp);

	void setState(state_t state, time_t timestamp);

	void setValue(state_t state, const T& value);

	/**
	* Updates the value by distributing the delta from the previously set value
	* among states according to their respective time-in-state.
	* Returns the delta from the previously set value.
	*/
	const T& updateValue(const T& value, time_t timestamp);

	/**
	* Updates the value by distributing the specified increment among states according
	* to their respective time-in-state.
	*/
	void incrementValue(const T& increment, time_t timestamp);

	/**
	* Adds the specified increment to the value for the current state, without affecting
	* the last updated value or timestamp. Ignores partial time-in-state: the entirety of
	* the increment is given to the current state.
	*/
	void addValue(const T& increment);

	void reset();

	uint16_t getStateCount();

	const T& getCount(state_t state);

	std::string toString();

	private:
	/**
	* Subtracts previousValue from newValue and returns the result in outValue.
	* Returns true iff the combination of previousValue and newValue is valid
	* (newValue >= prevValue)
	*/
	bool delta(const T& previousValue, const T& newValue, T* outValue) const;

	/**
	* Adds value2 to value1 and stores the result in value1. Denominator is
	* guaranteed to be non-zero.
	*/
	void add(T* value1, const T& value2, const uint64_t numerator,
	const uint64_t denominator) const;

	std::string valueToString(const T& value) const;
	};

	// ---------------------- MultiStateCounter Implementation -------------------------
	// Since MultiStateCounter is a template, the implementation must be inlined.

	template <class T>
	MultiStateCounter<T>::MultiStateCounter(uint16_t stateCount, const T& emptyValue)
	: stateCount(stateCount),
	currentState(0),
	lastStateChangeTimestamp(-1),
	emptyValue(emptyValue),
	lastValue(emptyValue),
	lastUpdateTimestamp(-1),
	deltaValue(emptyValue),
	isEnabled(true) {
	states = new State[stateCount];
	for (int i = 0; i < stateCount; i++) {
	states[i].timeInStateSinceUpdate = 0;
	states[i].counter = emptyValue;
	}
	}

	template <class T>
	MultiStateCounter<T>::~MultiStateCounter() {
	delete[] states;
	};

	template <class T>
	void MultiStateCounter<T>::setEnabled(bool enabled, time_t timestamp) {
	if (enabled == isEnabled) {
	return;
	}

	if (!enabled) {
	// Confirm the current state for the side-effect of updating the time-in-state
	// counter for the current state.
	setState(currentState, timestamp);
	}

	isEnabled = enabled;

	if (lastStateChangeTimestamp >= 0) {
	lastStateChangeTimestamp = timestamp;
	}
	}

	template <class T>
	void MultiStateCounter<T>::setState(state_t state, time_t timestamp) {
	if (isEnabled && lastStateChangeTimestamp >= 0) {
	if (timestamp >= lastStateChangeTimestamp) {
	states[currentState].timeInStateSinceUpdate += timestamp - lastStateChangeTimestamp;
	} else {
	ALOGE("setState is called with an earlier timestamp: %lu, previous timestamp: %lu\n",
	(unsigned long)timestamp, (unsigned long)lastStateChangeTimestamp);
	// The accumulated durations have become unreliable. For example, if the timestamp
	// sequence was 1000, 2000, 1000, 3000, if we accumulated the positive deltas,
	// we would get 4000, which is greater than (last - first). This could lead to
	// counts exceeding 100%.
	for (int i = 0; i < stateCount; i++) {
	states[i].timeInStateSinceUpdate = 0;
	}
	}
	}
	currentState = state;
	lastStateChangeTimestamp = timestamp;
	}

	template <class T>
	void MultiStateCounter<T>::setValue(state_t state, const T& value) {
	states[state].counter = value;
	}

	template <class T>
	const T& MultiStateCounter<T>::updateValue(const T& value, time_t timestamp) {
	T* returnValue = &emptyValue;

	// If the counter is disabled, we ignore the update, except when the counter got disabled after
	// the previous update, in which case we still need to pick up the residual delta.
	if (isEnabled \|\| lastUpdateTimestamp < lastStateChangeTimestamp) {
	// Confirm the current state for the side-effect of updating the time-in-state
	// counter for the current state.
	setState(currentState, timestamp);

	if (lastUpdateTimestamp >= 0) {
	if (timestamp > lastUpdateTimestamp) {
	if (delta(lastValue, value, &deltaValue)) {
	returnValue = &deltaValue;
	time_t timeSinceUpdate = timestamp - lastUpdateTimestamp;
	for (int i = 0; i < stateCount; i++) {
	time_t timeInState = states[i].timeInStateSinceUpdate;
	if (timeInState) {
	add(&states[i].counter, deltaValue, timeInState, timeSinceUpdate);
	states[i].timeInStateSinceUpdate = 0;
	}
	}
	} else {
	std::stringstream str;
	str << "updateValue is called with a value " << valueToString(value)
	<< ", which is lower than the previous value " << valueToString(lastValue)
	<< "\n";
	ALOGE("%s", str.str().c_str());

	for (int i = 0; i < stateCount; i++) {
	states[i].timeInStateSinceUpdate = 0;
	}
	}
	} else if (timestamp < lastUpdateTimestamp) {
	ALOGE("updateValue is called with an earlier timestamp: %lu, previous: %lu\n",
	(unsigned long)timestamp, (unsigned long)lastUpdateTimestamp);

	for (int i = 0; i < stateCount; i++) {
	states[i].timeInStateSinceUpdate = 0;
	}
	}
	}
	}
	lastValue = value;
	lastUpdateTimestamp = timestamp;
	return *returnValue;
	}

	template <class T>
	void MultiStateCounter<T>::incrementValue(const T& increment, time_t timestamp) {
	T newValue = lastValue;
	add(&newValue, increment, 1 /* numerator /, 1 / denominator */);
	updateValue(newValue, timestamp);
	}

	template <class T>
	void MultiStateCounter<T>::addValue(const T& value) {
	if (!isEnabled) {
	return;
	}
	add(&states[currentState].counter, value, 1 /* numerator /, 1 / denominator */);
	}

	template <class T>
	void MultiStateCounter<T>::reset() {
	lastStateChangeTimestamp = -1;
	lastUpdateTimestamp = -1;
	for (int i = 0; i < stateCount; i++) {
	states[i].timeInStateSinceUpdate = 0;
	states[i].counter = emptyValue;
	}
	}

	template <class T>
	uint16_t MultiStateCounter<T>::getStateCount() {
	return stateCount;
	}

	template <class T>
	const T& MultiStateCounter<T>::getCount(state_t state) {
	return states[state].counter;
	}

	template <class T>
	std::string MultiStateCounter<T>::toString() {
	std::stringstream str;
	str << "[";
	for (int i = 0; i < stateCount; i++) {
	if (i != 0) {
	str << ", ";
	}
	str << i << ": " << valueToString(states[i].counter);
	if (states[i].timeInStateSinceUpdate > 0) {
	str << " timeInStateSinceUpdate: " << states[i].timeInStateSinceUpdate;
	}
	}
	str << "]";
	if (lastUpdateTimestamp >= 0) {
	str << " updated: " << lastUpdateTimestamp;
	}
	if (lastStateChangeTimestamp >= 0) {
	str << " currentState: " << currentState;
	if (lastStateChangeTimestamp > lastUpdateTimestamp) {
	str << " stateChanged: " << lastStateChangeTimestamp;
	}
	} else {
	str << " currentState: none";
	}
	if (!isEnabled) {
	str << " disabled";
	}
	return str.str();
	}

	} // namespace battery
	} // namespace android