sensor: capi: add sensor_util_get_altitude API

- this API computes the altitude in meters from the atmospheric
  pressure, the pressure at sea level and the temperature.

Change-Id: Ic77516aeb067bb53b74720aedc5d49b91eab18ed
Signed-off-by: kibak.yoon <kibak.yoon@samsung.com>

diff --git a/include/sensor.h b/include/sensor.h
index 0005065..4449fa4 100644 (file)
--- a/include/sensor.h
+++ b/include/sensor.h
@@ -1900,6 +1900,24 @@ int sensor_util_get_angle_change(float R[], float prevR[], float angleChange[]);
  * @retval  #SENSOR_ERROR_INVALID_PARAMETER    Invalid parameter
  */
 int sensor_util_get_declination(float latitude, float longitude, float altitude, float* declination);
+
+/**
+ * @brief Gets the altitude from the atmospheric pressure, the pressure at sea level and temperature, in meters.
+ * @since_tizen 4.0
+ *
+ * @param[in]  pressure           The atmospheric pressure (hPa)
+ * @param[in]  sea_level_pressure The sea level pressure (hPa) @n
+ *                                If the sea level pressure is not known, you can use 1013.25 hPa, mean sea level pressure
+ * @param[in]  temperature        The temperature (degrees Celsius) @n
+ *                                If the temperature is not known, you can use 15 degrees Celsius
+ * @param[out] altitude           The altitude (meters)
+ *
+ * @return  #SENSOR_ERROR_NONE on success; Otherwise a negative error value
+ * @retval  #SENSOR_ERROR_NONE                 Successful
+ * @retval  #SENSOR_ERROR_INVALID_PARAMETER    Invalid parameter
+ */
+int sensor_util_get_altitude(float pressure, float sea_level_pressure, float temperature, float* altitude);
+
 /**
  * @}
  */

diff --git a/src/sensor.cpp b/src/sensor.cpp
index 4480902..f22b3de 100644 (file)
--- a/src/sensor.cpp
+++ b/src/sensor.cpp
@@ -973,3 +973,16 @@ int sensor_util_get_rotation_matrix(float Gx, float Gy, float Gz, float Mx, floa
        return SENSOR_ERROR_NONE;
 }
 
+int sensor_util_get_altitude(float pressure, float sea_level_pressure, float temperature, float* altitude)
+{
+       if (pressure <= 0)
+               return SENSOR_ERROR_INVALID_PARAMETER;
+       if (sea_level_pressure <= 0)
+               return SENSOR_ERROR_INVALID_PARAMETER;
+       if (!altitude)
+               return SENSOR_ERROR_INVALID_PARAMETER;
+
+       *altitude = (temperature + 273.15f) / 0.0065f * (1.0f - pow(pressure/sea_level_pressure, 1.0f/5.255f));
+
+       return SENSOR_ERROR_NONE;
+}