1 /* 2 * Copyright (C) 2017 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 #ifndef ANDROID_SENSOR_DEVICE_UTIL 18 #define ANDROID_SENSOR_DEVICE_UTIL 19 20 #include <android/hidl/manager/1.0/IServiceNotification.h> 21 #include <hardware/sensors.h> 22 #include <utils/Log.h> 23 24 #include <cmath> 25 #include <condition_variable> 26 #include <thread> 27 28 using ::android::hardware::hidl_string; 29 using ::android::hardware::Return; 30 using ::android::hidl::manager::V1_0::IServiceNotification; 31 32 namespace android { 33 namespace SensorDeviceUtils { 34 35 // Quantizes a single value to (a fractional factor of) a sensor's resolution. Typically we 36 // increase the value of the sensor's nominal resolution to ensure that sensor accuracy 37 // improvements, like runtime calibration, are not masked during requantization. 38 inline void quantizeValue(float *value, double resolution, double factor = 0.125) { 39 if (resolution == 0) { 40 return; 41 } 42 43 double incRes = factor * resolution; 44 *value = round(static_cast<double>(*value) / incRes) * incRes; 45 } 46 47 // Ensures a sensor event doesn't provide values finer grained than its sensor resolution allows. 48 void quantizeSensorEventValues(sensors_event_t *event, float resolution); 49 50 // Returns the expected resolution value for the given sensor 51 float resolutionForSensor(const sensor_t &sensor); 52 53 class HidlServiceRegistrationWaiter : public IServiceNotification { 54 public: 55 56 HidlServiceRegistrationWaiter(); 57 58 Return<void> onRegistration(const hidl_string &fqName, 59 const hidl_string &name, 60 bool preexisting) override; 61 62 void reset(); 63 64 /** 65 * Wait for service restart 66 * 67 * @return true if service is restart since last reset(); false otherwise. 68 */ 69 bool wait(); 70 protected: 71 void onFirstRef() override; 72 private: 73 bool mRegistered; 74 75 std::mutex mLock; 76 std::condition_variable mCondition; 77 bool mRestartObserved; 78 }; 79 80 } // namespace SensorDeviceUtils 81 } // namespace android; 82 83 #endif // ANDROID_SENSOR_SERVICE_UTIL 84