2022-01-01 23:50:23 +01:00

671 lines
24 KiB
C

#ifndef _XPLMDataAccess_h_
#define _XPLMDataAccess_h_
/*
* Copyright 2005-2012 Sandy Barbour and Ben Supnik
*
* All rights reserved. See license.txt for usage.
*
* X-Plane SDK Version: 2.1.1
*
*/
/*
* XPLM Data Access API - Theory of Operation
*
* The data access API gives you a generic, flexible, high performance way to
* read and write data to and from X-Plane and other plug-ins. For example,
* this API allows you to read and set the nav radios, get the plane location,
* determine the current effective graphics frame rate, etc.
*
* The data access APIs are the way that you read and write data from the sim
* as well as other plugins.
*
* The API works using opaque data references. A data reference is a source
* of data; you do not know where it comes from, but once you have it you can
* read the data quickly and possibly write it. To get a data reference, you
* look it up.
*
* Data references are identified by verbose string names
* (sim/cockpit/radios/nav1_freq_hz). The actual numeric value of the data
* reference is implementation defined and is likely to change each time the
* simulator is run (or the plugin that provides the datareference is
* reloaded).
*
* The task of looking up a data reference is relatively expensive; look up
* your data references once based on verbose strings, and save the opaque
* data reference value for the duration of your plugin's operation. Reading
* and writing data references is relatively fast (the cost is equivalent to
* two function calls through function pointers).
*
* This allows data access to be high performance, while leaving in
* abstraction; since data references are opaque and are searched for, the
* underlying data access system can be rebuilt.
*
* A note on typing: you must know the correct data type to read and write.
* APIs are provided for reading and writing data in a number of ways. You
* can also double check the data type for a data ref. Note that automatic
* conversion is not done for you.
*
* A note for plugins sharing data with other plugins: the load order of
* plugins is not guaranteed. To make sure that every plugin publishing data
* has published their data references before other plugins try to subscribe,
* publish your data references in your start routine but resolve them the
* first time your 'enable' routine is called, or the first time they are
* needed in code.
*
* X-Plane publishes well over 1000 datarefs; a complete list may be found in
* the reference section of the SDK online documentation (from the SDK home
* page, choose Documentation).
*
*/
#include "XPLMDefs.h"
#ifdef __cplusplus
extern "C" {
#endif
/***************************************************************************
* READING AND WRITING DATA
***************************************************************************/
/*
* These routines allow you to access a wide variety of data from within
* x-plane and modify some of it.
*
*/
/*
* XPLMDataRef
*
* A data ref is an opaque handle to data provided by the simulator or another
* plugin. It uniquely identifies one variable (or array of variables) over
* the lifetime of your plugin. You never hard code these values; you always
* get them from XPLMFindDataRef.
*
*/
typedef void *XPLMDataRef;
/*
* XPLMDataTypeID
*
* This is an enumeration that defines the type of the data behind a data
* reference. This allows you to sanity check that the data type matches what
* you expect. But for the most part, you will know the type of data you are
* expecting from the online documentation.
*
* Data types each take a bit field, so sets of data types may be formed.
*
*/
enum {
/* Data of a type the current XPLM doesn't do. */
xplmType_Unknown = 0
/* A single 4-byte integer, native endian. */
,
xplmType_Int = 1
/* A single 4-byte float, native endian. */
,
xplmType_Float = 2
/* A single 8-byte double, native endian. */
,
xplmType_Double = 4
/* An array of 4-byte floats, native endian. */
,
xplmType_FloatArray = 8
/* An array of 4-byte integers, native endian. */
,
xplmType_IntArray = 16
/* A variable block of data. */
,
xplmType_Data = 32
};
typedef int XPLMDataTypeID;
/*
* XPLMFindDataRef
*
* Given a c-style string that names the data ref, this routine looks up the
* actual opaque XPLMDataRef that you use to read and write the data. The
* string names for datarefs are published on the x-plane SDK web site.
*
* This function returns NULL if the data ref cannot be found.
*
* NOTE: this function is relatively expensive; save the XPLMDataRef this
* function returns for future use. Do not look up your data ref by string
* every time you need to read or write it.
*
*/
XPLM_API XPLMDataRef XPLMFindDataRef(const char *inDataRefName);
/*
* XPLMCanWriteDataRef
*
* Given a data ref, this routine returns true if you can successfully set
* the data, false otherwise. Some datarefs are read-only.
*
*/
XPLM_API int XPLMCanWriteDataRef(XPLMDataRef inDataRef);
/*
* XPLMIsDataRefGood
*
* WARNING: This function is deprecated and should not be used. Datarefs are
* valid until plugins are reloaded or the sim quits. Plugins sharing
* datarefs should support these semantics by not unregistering datarefs
* during operation. (You should however unregister datarefs when your plugin
* is unloaded, as part of general resource cleanup.)
*
* This function returns whether a data ref is still valid. If it returns
* false, you should refind the data ref from its original string. Calling an
* accessor function on a bad data ref will return a default value, typically
* 0 or 0-length data.
*
*/
XPLM_API int XPLMIsDataRefGood(XPLMDataRef inDataRef);
/*
* XPLMGetDataRefTypes
*
* This routine returns the types of the data ref for accessor use. If a data
* ref is available in multiple data types, they will all be returned.
*
*/
XPLM_API XPLMDataTypeID XPLMGetDataRefTypes(XPLMDataRef inDataRef);
/***************************************************************************
* DATA ACCESSORS
***************************************************************************/
/*
* These routines read and write the data references. For each supported data
* type there is a reader and a writer.
*
* If the data ref is invalid or the plugin that provides it is disabled or
* there is a type mismatch, the functions that read data will return 0 as a
* default value or not modify the passed in memory. The plugins that write
* data will not write under these circumstances or if the data ref is
* read-only. NOTE: to keep the overhead of reading datarefs low, these
* routines do not do full validation of a dataref; passing a junk value for
* a dataref can result in crashing the sim.
*
* For array-style datarefs, you specify the number of items to read/write and
* the offset into the array; the actual number of items read or written is
* returned. This may be less to prevent an array-out-of-bounds error.
*
*/
/*
* XPLMGetDatai
*
* Read an integer data ref and return its value. The return value is the
* dataref value or 0 if the dataref is invalid/NULL or the plugin is
* disabled.
*
*/
XPLM_API int XPLMGetDatai(XPLMDataRef inDataRef);
/*
* XPLMSetDatai
*
* Write a new value to an integer data ref. This routine is a no-op if the
* plugin publishing the dataref is disabled, the dataref is invalid, or the
* dataref is not writable.
*
*/
XPLM_API void XPLMSetDatai(XPLMDataRef inDataRef, int inValue);
/*
* XPLMGetDataf
*
* Read a single precision floating point dataref and return its value. The
* return value is the dataref value or 0.0 if the dataref is invalid/NULL or
* the plugin is disabled.
*
*/
XPLM_API float XPLMGetDataf(XPLMDataRef inDataRef);
/*
* XPLMSetDataf
*
* Write a new value to a single precision floating point data ref. This
* routine is a no-op if the plugin publishing the dataref is disabled, the
* dataref is invalid, or the dataref is not writable.
*
*/
XPLM_API void XPLMSetDataf(XPLMDataRef inDataRef, float inValue);
/*
* XPLMGetDatad
*
* Read a double precision floating point dataref and return its value. The
* return value is the dataref value or 0.0 if the dataref is invalid/NULL or
* the plugin is disabled.
*
*/
XPLM_API double XPLMGetDatad(XPLMDataRef inDataRef);
/*
* XPLMSetDatad
*
* Write a new value to a double precision floating point data ref. This
* routine is a no-op if the plugin publishing the dataref is disabled, the
* dataref is invalid, or the dataref is not writable.
*
*/
XPLM_API void XPLMSetDatad(XPLMDataRef inDataRef, double inValue);
/*
* XPLMGetDatavi
*
* Read a part of an integer array dataref. If you pass NULL for outVaules,
* the routine will return the size of the array, ignoring inOffset and inMax.
*
*
* If outValues is not NULL, then up to inMax values are copied from the
* dataref into outValues, starting at inOffset in the dataref. If inMax +
* inOffset is larger than the size of the dataref, less than inMax values
* will be copied. The number of values copied is returned.
*
* Note: the semantics of array datarefs are entirely implemented by the
* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
* above description is how these datarefs are intended to work, but a rogue
* plugin may have different behavior.
*
*/
XPLM_API int XPLMGetDatavi(XPLMDataRef inDataRef,
int *outValues, /* Can be NULL */
int inOffset,
int inMax);
/*
* XPLMSetDatavi
*
* Write part or all of an integer array dataref. The values passed by
* inValues are written into the dataref starting at inOffset. Up to inCount
* values are written; however if the values would write "off the end" of the
* dataref array, then fewer values are written.
*
* Note: the semantics of array datarefs are entirely implemented by the
* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
* above description is how these datarefs are intended to work, but a rogue
* plugin may have different behavior.
*
*/
XPLM_API void XPLMSetDatavi(XPLMDataRef inDataRef,
int *inValues,
int inoffset,
int inCount);
/*
* XPLMGetDatavf
*
* Read a part of a single precision floating point array dataref. If you
* pass NULL for outVaules, the routine will return the size of the array,
* ignoring inOffset and inMax.
*
* If outValues is not NULL, then up to inMax values are copied from the
* dataref into outValues, starting at inOffset in the dataref. If inMax +
* inOffset is larger than the size of the dataref, less than inMax values
* will be copied. The number of values copied is returned.
*
* Note: the semantics of array datarefs are entirely implemented by the
* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
* above description is how these datarefs are intended to work, but a rogue
* plugin may have different behavior.
*
*/
XPLM_API int XPLMGetDatavf(XPLMDataRef inDataRef,
float *outValues, /* Can be NULL */
int inOffset,
int inMax);
/*
* XPLMSetDatavf
*
* Write part or all of a single precision floating point array dataref. The
* values passed by inValues are written into the dataref starting at
* inOffset. Up to inCount values are written; however if the values would
* write "off the end" of the dataref array, then fewer values are written.
*
* Note: the semantics of array datarefs are entirely implemented by the
* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
* above description is how these datarefs are intended to work, but a rogue
* plugin may have different behavior.
*
*/
XPLM_API void XPLMSetDatavf(XPLMDataRef inDataRef,
float *inValues,
int inoffset,
int inCount);
/*
* XPLMGetDatab
*
* Read a part of a byte array dataref. If you pass NULL for outVaules, the
* routine will return the size of the array, ignoring inOffset and inMax.
*
* If outValues is not NULL, then up to inMax values are copied from the
* dataref into outValues, starting at inOffset in the dataref. If inMax +
* inOffset is larger than the size of the dataref, less than inMax values
* will be copied. The number of values copied is returned.
*
* Note: the semantics of array datarefs are entirely implemented by the
* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
* above description is how these datarefs are intended to work, but a rogue
* plugin may have different behavior.
*
*/
XPLM_API int XPLMGetDatab(XPLMDataRef inDataRef,
void *outValue, /* Can be NULL */
int inOffset,
int inMaxBytes);
/*
* XPLMSetDatab
*
* Write part or all of a byte array dataref. The values passed by inValues
* are written into the dataref starting at inOffset. Up to inCount values
* are written; however if the values would write "off the end" of the dataref
* array, then fewer values are written.
*
* Note: the semantics of array datarefs are entirely implemented by the
* plugin (or X-Plane) that provides the dataref, not the SDK itself; the
* above description is how these datarefs are intended to work, but a rogue
* plugin may have different behavior.
*
*/
XPLM_API void XPLMSetDatab(XPLMDataRef inDataRef,
void *inValue,
int inOffset,
int inLength);
/***************************************************************************
* PUBLISHING YOUR PLUGINS DATA
***************************************************************************/
/*
* These functions allow you to create data references that other plug-ins can
* access via the above data access APIs. Data references published by other
* plugins operate the same as ones published by x-plane in all manners except
* that your data reference will not be available to other plugins if/when
* your plugin is disabled.
*
* You share data by registering data provider callback functions. When a
* plug-in requests your data, these callbacks are then called. You provide
* one callback to return the value when a plugin 'reads' it and another to
* change the value when a plugin 'writes' it.
*
* Important: you must pick a prefix for your datarefs other than "sim/" -
* this prefix is reserved for X-Plane. The X-Plane SDK website contains a
* registry where authors can select a unique first word for dataref names, to
* prevent dataref collisions between plugins.
*
*/
/*
* XPLMGetDatai_f
*
* Data provider function pointers.
*
* These define the function pointers you provide to get or set data. Note
* that you are passed a generic pointer for each one. This is the same
* pointer you pass in your register routine; you can use it to find global
* variables, etc.
*
* The semantics of your callbacks are the same as the dataref accessor above
* - basically routines like XPLMGetDatai are just pass-throughs from a caller
* to your plugin. Be particularly mindful in implementing array dataref
* read-write accessors; you are responsible for avoiding overruns, supporting
* offset read/writes, and handling a read with a NULL buffer.
*
*/
typedef int (*XPLMGetDatai_f)(void *inRefcon);
/*
* XPLMSetDatai_f
*
*
*/
typedef void (*XPLMSetDatai_f)(void *inRefcon, int inValue);
/*
* XPLMGetDataf_f
*
*
*/
typedef float (*XPLMGetDataf_f)(void *inRefcon);
/*
* XPLMSetDataf_f
*
*
*/
typedef void (*XPLMSetDataf_f)(void *inRefcon, float inValue);
/*
* XPLMGetDatad_f
*
*
*/
typedef double (*XPLMGetDatad_f)(void *inRefcon);
/*
* XPLMSetDatad_f
*
*
*/
typedef void (*XPLMSetDatad_f)(void *inRefcon, double inValue);
/*
* XPLMGetDatavi_f
*
*
*/
typedef int (*XPLMGetDatavi_f)(void *inRefcon,
int *outValues, /* Can be NULL */
int inOffset,
int inMax);
/*
* XPLMSetDatavi_f
*
*
*/
typedef void (*XPLMSetDatavi_f)(void *inRefcon,
int *inValues,
int inOffset,
int inCount);
/*
* XPLMGetDatavf_f
*
*
*/
typedef int (*XPLMGetDatavf_f)(void *inRefcon,
float *outValues, /* Can be NULL */
int inOffset,
int inMax);
/*
* XPLMSetDatavf_f
*
*
*/
typedef void (*XPLMSetDatavf_f)(void *inRefcon,
float *inValues,
int inOffset,
int inCount);
/*
* XPLMGetDatab_f
*
*
*/
typedef int (*XPLMGetDatab_f)(void *inRefcon,
void *outValue, /* Can be NULL */
int inOffset,
int inMaxLength);
/*
* XPLMSetDatab_f
*
*
*/
typedef void (*XPLMSetDatab_f)(void *inRefcon,
void *inValue,
int inOffset,
int inLength);
/*
* XPLMRegisterDataAccessor
*
* This routine creates a new item of data that can be read and written. Pass
* in the data's full name for searching, the type(s) of the data for
* accessing, and whether the data can be written to. For each data type you
* support, pass in a read accessor function and a write accessor function if
* necessary. Pass NULL for data types you do not support or write accessors
* if you are read-only.
*
* You are returned a data ref for the new item of data created. You can use
* this data ref to unregister your data later or read or write from it.
*
*/
XPLM_API XPLMDataRef XPLMRegisterDataAccessor(const char *inDataName,
XPLMDataTypeID inDataType,
int inIsWritable,
XPLMGetDatai_f inReadInt,
XPLMSetDatai_f inWriteInt,
XPLMGetDataf_f inReadFloat,
XPLMSetDataf_f inWriteFloat,
XPLMGetDatad_f inReadDouble,
XPLMSetDatad_f inWriteDouble,
XPLMGetDatavi_f inReadIntArray,
XPLMSetDatavi_f inWriteIntArray,
XPLMGetDatavf_f inReadFloatArray,
XPLMSetDatavf_f inWriteFloatArray,
XPLMGetDatab_f inReadData,
XPLMSetDatab_f inWriteData,
void *inReadRefcon,
void *inWriteRefcon);
/*
* XPLMUnregisterDataAccessor
*
* Use this routine to unregister any data accessors you may have registered.
* You unregister a data ref by the XPLMDataRef you get back from
* registration. Once you unregister a data ref, your function pointer will
* not be called anymore.
*
* For maximum compatibility, do not unregister your data accessors until
* final shutdown (when your XPluginStop routine is called). This allows
* other plugins to find your data reference once and use it for their entire
* time of operation.
*
*/
XPLM_API void XPLMUnregisterDataAccessor(XPLMDataRef inDataRef);
/***************************************************************************
* SHARING DATA BETWEEN MULTIPLE PLUGINS
***************************************************************************/
/*
* The data reference registration APIs from the previous section allow a
* plugin to publish data in a one-owner manner; the plugin that publishes the
* data reference owns the real memory that the data ref uses. This is
* satisfactory for most cases, but there are also cases where plugnis need to
* share actual data.
*
* With a shared data reference, no one plugin owns the actual memory for the
* data reference; the plugin SDK allocates that for you. When the first
* plugin asks to 'share' the data, the memory is allocated. When the data is
* changed, every plugin that is sharing the data is notified.
*
* Shared data references differ from the 'owned' data references from the
* previous section in a few ways:
*
* - With shared data references, any plugin can create the data reference;
* with owned plugins one plugin must create the data reference and others
* subscribe. (This can be a problem if you don't know which set of plugins
* will be present).
*
* - With shared data references, every plugin that is sharing the data is
* notified when the data is changed. With owned data references, only the
* one owner is notified when the data is changed.
*
* - With shared data references, you cannot access the physical memory of the
* data reference; you must use the XPLMGet... and XPLMSet... APIs. With an
* owned data reference, the one owning data reference can manipulate the
* data reference's memory in any way it sees fit.
*
* Shared data references solve two problems: if you need to have a data
* reference used by several plugins but do not know which plugins will be
* installed, or if all plugins sharing data need to be notified when that
* data is changed, use shared data references.
*
*/
/*
* XPLMDataChanged_f
*
* An XPLMDataChanged_f is a callback that the XPLM calls whenever any other
* plug-in modifies shared data. A refcon you provide is passed back to help
* identify which data is being changed. In response, you may want to call one
* of the XPLMGetDataxxx routines to find the new value of the data.
*
*/
typedef void (*XPLMDataChanged_f)(void *inRefcon);
/*
* XPLMShareData
*
* This routine connects a plug-in to shared data, creating the shared data if
* necessary. inDataName is a standard path for the data ref, and inDataType
* specifies the type. This function will create the data if it does not
* exist. If the data already exists but the type does not match, an error is
* returned, so it is important that plug-in authors collaborate to establish
* public standards for shared data.
*
* If a notificationFunc is passed in and is not NULL, that notification
* function will be called whenever the data is modified. The notification
* refcon will be passed to it. This allows your plug-in to know which shared
* data was changed if multiple shared data are handled by one callback, or if
* the plug-in does not use global variables.
*
* A one is returned for successfully creating or finding the shared data; a
* zero if the data already exists but is of the wrong type.
*
*/
XPLM_API int XPLMShareData(const char *inDataName,
XPLMDataTypeID inDataType,
XPLMDataChanged_f inNotificationFunc,
void *inNotificationRefcon);
/*
* XPLMUnshareData
*
* This routine removes your notification function for shared data. Call it
* when done with the data to stop receiving change notifications. Arguments
* must match XPLMShareData. The actual memory will not necessarily be freed,
* since other plug-ins could be using it.
*
*/
XPLM_API int XPLMUnshareData(const char *inDataName,
XPLMDataTypeID inDataType,
XPLMDataChanged_f inNotificationFunc,
void *inNotificationRefcon);
#ifdef __cplusplus
}
#endif
#endif