First pass on the new SDL sensor API

src/sensor/SDL_syssensor.h

@@ -0,0 +1,97 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2018 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "SDL_config.h"
+
+/* This is the system specific header for the SDL sensor API */
+
+#include "SDL_sensor.h"
+#include "SDL_sensor_c.h"
+
+/* The SDL sensor structure */
+struct _SDL_Sensor
+{
+    SDL_SensorID instance_id;       /* Device instance, monotonically increasing from 0 */
+    char *name;                     /* Sensor name - system dependent */
+    SDL_SensorType type;            /* Type of the sensor */
+    int non_portable_type;          /* Platform dependent type of the sensor */
+
+    float data[16];                 /* The current state of the sensor */
+
+    struct _SDL_SensorDriver *driver;
+
+    struct sensor_hwdata *hwdata;   /* Driver dependent information */
+
+    int ref_count;                  /* Reference count for multiple opens */
+
+    struct _SDL_Sensor *next;       /* pointer to next sensor we have allocated */
+};
+
+typedef struct _SDL_SensorDriver
+{
+    /* Function to scan the system for sensors.
+     * sensor 0 should be the system default sensor.
+     * This function should return 0, or -1 on an unrecoverable fatal error.
+     */
+    int (*Init)(void);
+
+    /* Function to return the number of sensors available right now */
+    int (*GetCount)(void);
+
+    /* Function to check to see if the available sensors have changed */
+    void (*Detect)(void);
+
+    /* Function to get the device-dependent name of a sensor */
+    const char *(*GetDeviceName)(int device_index);
+
+    /* Function to get the type of a sensor */
+    SDL_SensorType (*GetDeviceType)(int device_index);
+
+    /* Function to get the platform dependent type of a sensor */
+    int (*GetDeviceNonPortableType)(int device_index);
+
+    /* Function to get the current instance id of the sensor located at device_index */
+    SDL_SensorID (*GetDeviceInstanceID)(int device_index);
+
+    /* Function to open a sensor for use.
+       The sensor to open is specified by the device index.
+       It returns 0, or -1 if there is an error.
+     */
+    int (*Open)(SDL_Sensor * sensor, int device_index);
+
+    /* Function to update the state of a sensor - called as a device poll.
+     * This function shouldn't update the sensor structure directly,
+     * but instead should call SDL_PrivateSensorUpdate() to deliver events
+     * and update sensor device state.
+     */
+    void (*Update)(SDL_Sensor * sensor);
+
+    /* Function to close a sensor after use */
+    void (*Close)(SDL_Sensor * sensor);
+
+    /* Function to perform any system-specific sensor related cleanup */
+    void (*Quit)(void);
+
+} SDL_SensorDriver;
+
+/* The available sensor drivers */
+extern SDL_SensorDriver SDL_ANDROID_SensorDriver;
+
+/* vi: set ts=4 sw=4 expandtab: */