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      1 /*
      2  * Copyright (C) 2008-2014 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_BASE_H
     18 #define ANDROID_SENSOR_BASE_H
     19 
     20 #include <errno.h>
     21 #include <stdint.h>
     22 #include <sys/cdefs.h>
     23 #include <sys/types.h>
     24 
     25 
     26 /*****************************************************************************/
     27 
     28 struct sensors_event_t;
     29 
     30 #define NS_PER_SEC 1000000000LL
     31 #define NS_PER_US 1000
     32 
     33 class SensorBase {
     34 protected:
     35     const char* dev_name;
     36     const char* data_name;
     37     int         dev_fd;
     38     int         data_fd;
     39 
     40     static int64_t getTimestamp();
     41 
     42 
     43     static int64_t timevalToNano(timeval const& t) {
     44         return t.tv_sec*NS_PER_SEC + t.tv_usec*NS_PER_US;
     45     }
     46 
     47     int open_device();
     48     int close_device();
     49     int write_int(char const *path, int value);
     50     int write_sys_attribute(
     51     char const *path, char const *value, int bytes);
     52 
     53 public:
     54             SensorBase(
     55                     const char* dev_name,
     56                     const char* data_name);
     57 
     58     virtual ~SensorBase();
     59 
     60     virtual int readEvents(sensors_event_t* data, int count) = 0;
     61     virtual bool hasPendingEvents() const;
     62     virtual int getFd() const;
     63     virtual int getPollTime() { return -1; }
     64     virtual int setDelay(int32_t handle, int64_t ns);
     65     virtual int64_t getDelay(int32_t handle);
     66 
     67     // When this function is called, increments the reference counter.
     68     virtual int setEnable(int32_t handle, int enabled) = 0;
     69     // It returns the number of reference.
     70     virtual int getEnable(int32_t handle) = 0;
     71     virtual int batch(int handle, int flags, int64_t period_ns, int64_t timeout) = 0;
     72     virtual int flush(int handle) = 0;
     73 };
     74 
     75 /*****************************************************************************/
     76 
     77 #endif  // ANDROID_SENSOR_BASE_H
     78