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      1 /*
      2  * Copyright (C) 2011 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_SENSORS_PORT_H_
     18 #define ANDROID_SENSORS_PORT_H_
     19 
     20 /*
     21  * Encapsulates exchange protocol between the sensor emulator, and an application
     22  * running on an Android device that provides sensor values, and is connected to
     23  * the host via USB.
     24  */
     25 
     26 #include "android/android-device.h"
     27 
     28 /* Declares sensors port descriptor. */
     29 typedef struct AndroidSensorsPort AndroidSensorsPort;
     30 
     31 /* Creates sensors port, and connects it to the device.
     32  * Param:
     33  *  opaque - An opaque pointer that is passed back to the callback routines.
     34  * Return:
     35  *  Initialized device descriptor on success, or NULL on failure. If failure is
     36  *  returned from this routine, 'errno' indicates the reason for failure. If this
     37  *  routine successeds, a connection is established with the sensor reading
     38  *  application on the device.
     39  */
     40 extern AndroidSensorsPort* sensors_port_create(void* opaque);
     41 
     42 /* Disconnects from the sensors port, and destroys the descriptor. */
     43 extern void sensors_port_destroy(AndroidSensorsPort* asp);
     44 
     45 /* Initializes sensors on the connected device. */
     46 extern int sensors_port_init_sensors(AndroidSensorsPort* asp);
     47 
     48 /* Checks if port is connected to a sensor reading application on the device.
     49  * Note that connection can go out and then be restored at any time after
     50  * sensors_port_create API succeeded.
     51  */
     52 extern int sensors_port_is_connected(AndroidSensorsPort* asp);
     53 
     54 /* Enables events from a particular sensor.
     55  * Param:
     56  *  asp - Android sensors port instance returned from sensors_port_create.
     57  *  name - Name of the sensor to enable events on. If this parameter is "all",
     58  *      then events on all sensors will be enabled.
     59  * Return:
     60  *  Zero on success, failure otherwise.
     61  */
     62 extern int sensors_port_enable_sensor(AndroidSensorsPort* asp, const char* name);
     63 
     64 
     65 /* Disables events from a particular sensor.
     66  * Param:
     67  *  asp - Android sensors port instance returned from sensors_port_create.
     68  *  name - Name of the sensor to disable events on. If this parameter is "all",
     69  *      then events on all sensors will be disable.
     70  * Return:
     71  *  Zero on success, failure otherwise.
     72  */
     73 extern int sensors_port_disable_sensor(AndroidSensorsPort* asp, const char* name);
     74 
     75 /* Queries the connected application to start delivering sensor events.
     76  * Param:
     77  *  asp - Android sensors port instance returned from sensors_port_create.
     78  * Return:
     79  *  Zero on success, failure otherwise.
     80  */
     81 extern int sensors_port_start(AndroidSensorsPort* asp);
     82 
     83 /* Queries the connected application to stop delivering sensor events.
     84  * Param:
     85  *  asp - Android sensors port instance returned from sensors_port_create.
     86  * Return:
     87  *  Zero on success, failure otherwise.
     88  */
     89 extern int sensors_port_stop(AndroidSensorsPort* asp);
     90 
     91 #endif  /* ANDROID_SENSORS_PORT_H_ */
     92