HID Support/HID_Queue_Utilities.c

/*
 *  HID_Queue_Utilities.c
 *  HID Explorer
 *
 *  Created by ggs on Tue May 08 2001.
 
    Copyright:  Copyright © 2001 Apple Computer, Inc., All Rights Reserved
 
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#include "HID_Utilities_Internal.h"
#include "HID_Utilities_External.h"
 
static IOReturn HIDCreateQueue (pRecDevice pDevice);
static unsigned char HIDIsDeviceQueueEmpty (pRecDevice pDevice);
static IOReturn HIDDisposeReleaseQueue (pRecDevice pDevice);
 
// ==================================
// private functions
 
// creates a queue for a device, creates and opens device interface if required
 
static IOReturn HIDCreateQueue (pRecDevice pDevice)
{
    IOReturn result = kIOReturnSuccess;
    if (NULL == pDevice->queue) // do we already have a queue
    {   
        if (NULL != pDevice->interface) 
        {
            pDevice->queue =(void *) (*(IOHIDDeviceInterface **) pDevice->interface)->allocQueue (pDevice->interface); // alloc queue
            if (pDevice->queue)
            {
                result = (*(IOHIDQueueInterface **) pDevice->queue)->create (pDevice->queue, 0, kDeviceQueueSize); // create actual queue
                if (kIOReturnSuccess != result)
                    HIDReportErrorNum ("Failed to create queue via create", result);
            }
            else
            {
                HIDReportError ("Failed to alloc IOHIDQueueInterface ** via allocQueue");
                result = kIOReturnError; // synthesis error
            }
        }
        else
            HIDReportErrorNum ("Device inteface does not exist for queue creation", result);
    }
    return result;
}
 
// ---------------------------------
 
// returns true if queue is empty false otherwise
// error if no device, empty if no queue
 
static unsigned char HIDIsDeviceQueueEmpty (pRecDevice pDevice)
{
    if (pDevice && pDevice->queue) // need device and queue
    {
        pRecElement pElement = HIDGetFirstDeviceElement (pDevice, kHIDElementTypeIO);
        while (pElement)
        {
            if ((*(IOHIDQueueInterface **) pDevice->queue)->hasElement (pDevice->queue, pElement->cookie))
                return false;
            pElement = HIDGetNextDeviceElement (pElement, kHIDElementTypeIO);
        } 
    }
    else if (NULL == pDevice) // if no device (if just no queue then queue must be empty)
        HIDReportError ("NULL device passed to DeviceQueueEmpty.");
    return true;   
}
 
// ---------------------------------
 
// disposes and releases queue, sets queue to NULL,.
// Note: will have no effect if device or queue do not exist
 
static IOReturn HIDDisposeReleaseQueue (pRecDevice pDevice)
{
    IOReturn result = kIOReturnSuccess;
 
    if ((NULL != pDevice) && (NULL != pDevice->queue))
    {
        // stop queue
        result = (*(IOHIDQueueInterface **) pDevice->queue)->stop (pDevice->queue);
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to stop queue.", result);
        // dispose of queue
        result = (*(IOHIDQueueInterface **) pDevice->queue)->dispose (pDevice->queue);
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to dipose queue.", result);
        // release the queue
        result = (*(IOHIDQueueInterface **) pDevice->queue)->Release (pDevice->queue);
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to release queue.", result);
            
        pDevice->queue = NULL;
    }
    return result;
}
 
// ==================================
// public functions
 
// Create and open an interface to device, required prior to extracting values or building queues
// Note: appliction now owns the device and must close and release it prior to exiting
 
IOReturn HIDCreateOpenDeviceInterface (io_object_t hidDevice, pRecDevice pDevice)
{
    IOReturn result = kIOReturnSuccess;
    HRESULT plugInResult = S_OK;
    SInt32 score = 0;
    IOCFPlugInInterface ** ppPlugInInterface = NULL;
    
    if (NULL == pDevice->interface)
    {
        result = IOCreatePlugInInterfaceForService (hidDevice, kIOHIDDeviceUserClientTypeID,
                                                    kIOCFPlugInInterfaceID, &ppPlugInInterface, &score);
        if (kIOReturnSuccess == result)
        {
            // Call a method of the intermediate plug-in to create the device interface
            plugInResult = (*ppPlugInInterface)->QueryInterface (ppPlugInInterface, 
                                CFUUIDGetUUIDBytes (kIOHIDDeviceInterfaceID), (void *) &(pDevice->interface));
            if (S_OK != plugInResult)
                HIDReportErrorNum ("CouldnÕt query HID class device interface from plugInInterface", plugInResult);
            IODestroyPlugInInterface (ppPlugInInterface); // replace (*ppPlugInInterface)->Release (ppPlugInInterface)
        }
        else
            HIDReportErrorNum ("Failed to create **plugInInterface via IOCreatePlugInInterfaceForService.", result);
    }
    if (NULL != pDevice->interface)
    {
        result = (*(IOHIDDeviceInterface **)pDevice->interface)->open (pDevice->interface, 0);
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to open pDevice->interface via open.", result);
    }
    return result;
}
 
// ---------------------------------
 
// queues specific element, performing any device queue set up required
// queue is started and ready to return events on exit from this function
 
unsigned long  HIDQueueElement (pRecDevice pDevice, pRecElement pElement)
{
    IOReturn result = kIOReturnSuccess;
 
    // error checking
    if ((NULL == pDevice) || (NULL == pElement))
    {
        HIDReportError ("Device or element does not exist, cannot queue element.");
        return kIOReturnBadArgument;
    }
    if (NULL == pDevice->interface) // must have interface
    {
        HIDReportError ("Device does not have interface, cannot queue element.");
        return kIOReturnError;
    }
    if (NULL == pDevice->queue) // if no queue create queue
        result = HIDCreateQueue (pDevice);
    if ((kIOReturnSuccess != result) || (NULL == pDevice->queue))
    {
        HIDReportErrorNum ("Could not queue element due to problem creating queue.", result);
        if (kIOReturnSuccess != result)
            return result;
        else
            return kIOReturnError;
    }
 
    // stop queue
    result = (*(IOHIDQueueInterface **) pDevice->queue)->stop (pDevice->queue);
    if (kIOReturnSuccess != result)
        HIDReportError ("Failed to stop queue.");
 
    // queue element
    if (!(*(IOHIDQueueInterface **) pDevice->queue)->hasElement (pDevice->queue, pElement->cookie))
    {
        result = (*(IOHIDQueueInterface **) pDevice->queue)->addElement (pDevice->queue, pElement->cookie, 0);
        if (kIOReturnSuccess != result)
            HIDReportError ("Failed to add element to queue via addElement.");
    }
 
    // restart queue
    result = (*(IOHIDQueueInterface **) pDevice->queue)->start (pDevice->queue);
    if (kIOReturnSuccess != result)
        HIDReportError ("Failed to start queue.");
 
   return result;
}
 
// ---------------------------------
 
// adds all elements to queue, performing any device queue set up required
// queue is started and ready to return events on exit from this function
 
unsigned long  HIDQueueDevice (pRecDevice pDevice)
{
    IOReturn result = kIOReturnSuccess;
    pRecElement pElement;
    
    // error checking
    if (NULL == pDevice)
    {
        HIDReportError ("Device does not exist, cannot queue device.");
        return kIOReturnBadArgument;
    }
    if (NULL == pDevice->interface) // must have interface
    {
        HIDReportError ("Device does not have interface, cannot queue device.");
        return kIOReturnError;
    }
    if (NULL == pDevice->queue) // if no queue create queue
        result = HIDCreateQueue (pDevice);
    if ((kIOReturnSuccess != result) || (NULL == pDevice->queue))
    {
        HIDReportErrorNum ("Could not queue device due to problem creating queue.", result);
        if (kIOReturnSuccess != result)
            return result;
        else
            return kIOReturnError;
    }
 
    // stop queue
    result = (*(IOHIDQueueInterface **) pDevice->queue)->stop (pDevice->queue);
    if (kIOReturnSuccess != result)
        HIDReportErrorNum ("Failed to stop queue.", result);
 
    // queue element
    pElement = HIDGetFirstDeviceElement (pDevice, kHIDElementTypeIO);
    while (pElement)
    {
        if (!(*(IOHIDQueueInterface **) pDevice->queue)->hasElement (pDevice->queue, pElement->cookie))
        {
            result = (*(IOHIDQueueInterface **) pDevice->queue)->addElement (pDevice->queue, pElement->cookie, 0);
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("Failed to add element to queue via addElement", result);
        }
        pElement = HIDGetNextDeviceElement (pElement, kHIDElementTypeIO);
    }    
 
    // start queue
    result = (*(IOHIDQueueInterface **) pDevice->queue)->start (pDevice->queue);
    if (kIOReturnSuccess != result)
        HIDReportErrorNum ("Failed to start queue.", result);
 
    return result;
}
 
// ---------------------------------
 
// removes element for queue, if last element in queue will release queue and closes device interface
 
unsigned long  HIDDequeueElement (pRecDevice pDevice, pRecElement pElement)
{
    IOReturn result = kIOReturnSuccess;
    if (!pDevice || !pElement)
        result = kIOReturnBadArgument;
    else
    {
        if ((pDevice->interface) && (pDevice->queue))
        {
            // stop queue
            result = (*(IOHIDQueueInterface **) pDevice->queue)->stop (pDevice->queue);
            if (kIOReturnSuccess != result)
                HIDReportErrorNum ("Failed to stop queue.", result);
        
            if ((*(IOHIDQueueInterface **) pDevice->queue)->hasElement (pDevice->queue, pElement->cookie)) // if has element then remove
            {
                result = (*(IOHIDQueueInterface **) pDevice->queue)->removeElement (pDevice->queue, pElement->cookie);
                if (kIOReturnSuccess != result)
                    HIDReportErrorNum ("Failed to add element to queue via addElement", result);
            }
            
            if (HIDIsDeviceQueueEmpty (pDevice)) // release device queue and close interface if queue empty
            {
                result = HIDDisposeReleaseQueue (pDevice);
                if (kIOReturnSuccess != result)
                    HIDReportErrorNum ("Failed to dispose and release queue.", result);
            }
            else // not empty so restart queue
            {
                result = (*(IOHIDQueueInterface **) pDevice->queue)->start (pDevice->queue);
                if (kIOReturnSuccess != result)
                    HIDReportErrorNum ("Failed to start queue.", result);
            }
        }
        else
        {
            HIDReportError ("No device inteface or queue.");
            return kIOReturnError;
        }
    }
    return result;
}
 
// ---------------------------------
 
// completely removes all elements from queue and releases queue and closes device interface
// does not release device interfaces, application must call ReleaseHIDDeviceList on exit
 
unsigned long  HIDDequeueDevice (pRecDevice pDevice)
{
    IOReturn result = kIOReturnSuccess;
    if (!pDevice)
        result = kIOReturnBadArgument;
    else
    {
        if ((pDevice->interface) && (pDevice->queue))
        {
            // iterate through elements and if queued, remove
            pRecElement pElement = HIDGetFirstDeviceElement (pDevice, kHIDElementTypeIO);
            while (pElement)
            {
                if ((*(IOHIDQueueInterface **) pDevice->queue)->hasElement (pDevice->queue, pElement->cookie))
                {
                    result = (*(IOHIDQueueInterface **) pDevice->queue)->removeElement (pDevice->queue, pElement->cookie);
                    if (kIOReturnSuccess != result)
                        HIDReportErrorNum ("Failed to add element to queue via addElement", result);
                }
                pElement = HIDGetNextDeviceElement (pElement, kHIDElementTypeIO);
            }    
        }
        // ensure queue is disposed and released
        // interface will be closed and released on call to ReleaseHIDDeviceList
        result = HIDDisposeReleaseQueue (pDevice);
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to dispose and release queue.", result);
    }
    return result;
}
 
// ---------------------------------
 
// releases all device queues for quit or rebuild (must be called)
// does not release device interfaces, application must call ReleaseHIDDeviceList on exit
 
IOReturn HIDReleaseAllDeviceQueues (void)
{
    IOReturn result = kIOReturnSuccess;
    pRecDevice pDevice = HIDGetFirstDevice ();
    while (pDevice)
    {
        result = HIDDequeueDevice (pDevice);
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Could not dequeue device.", result);
        pDevice = HIDGetNextDevice (pDevice);
    }
    return result;
}
 
// ---------------------------------
 
// Closes and releases interface to device, should be done prior to exting application
// Note: will have no affect if device or interface do not exist
// application will "own" the device if interface is not closed
// (device may have to be plug and re-plugged in different location to get it working again without a restart)
 
IOReturn HIDCloseReleaseInterface (pRecDevice pDevice)
{
    IOReturn result = kIOReturnSuccess;
    
    if ((NULL != pDevice) && (NULL != pDevice->interface))
    {
        // close the interface
        result = (*(IOHIDDeviceInterface **) pDevice->interface)->close (pDevice->interface);
        if (kIOReturnNotOpen == result)
        {
            //  do nothing as device was not opened, thus can't be closed
        }
        else if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to close IOHIDDeviceInterface.", result);
        //release the interface
        result = (*(IOHIDDeviceInterface **) pDevice->interface)->Release (pDevice->interface);
        if (kIOReturnSuccess != result)
            HIDReportErrorNum ("Failed to release IOHIDDeviceInterface.", result);
        pDevice->interface = NULL;
    }   
    return result;
}      
 
// ---------------------------------
 
// Get the next event in the queue for a device
// elements or entire device should be queued prior to calling this with HIDQueueElement or HIDQueueDevice
// returns true if an event is avialable for the element and fills out *pHIDEvent structure, returns false otherwise
// Note: kIOReturnUnderrun returned from getNextEvent indicates an empty queue not an error condition
// Note: application should pass in a pointer to a IOHIDEventStruct cast to a void (for CFM compatibility)
 
unsigned char HIDGetEvent (pRecDevice pDevice, void * pHIDEvent)
{
    IOReturn result = kIOReturnSuccess;
    AbsoluteTime zeroTime = {0,0};
    if (pDevice)
    {
        if (pDevice->queue)
        {
            result = (*(IOHIDQueueInterface **) pDevice->queue)->getNextEvent (pDevice->queue, (IOHIDEventStruct *)pHIDEvent, zeroTime, 0);
            if (kIOReturnUnderrun == result)
                return false;  // no events in queue not an error per say
            else if (kIOReturnSuccess != result) // actual error versus just an empty queue
                HIDReportErrorNum ("Could not get HID event via getNextEvent.", result);
            else
                return true;
        }
        else
            HIDReportError ("Could not get HID event, queue does not exist.");
    }
    else
        HIDReportError ("Could not get HID event, device does not exist.");
    return false; // did not get event
}
 
// ---------------------------------
 
// returns current value for element, polling element
// will return 0 on error conditions which should be accounted for by application
 
long HIDGetElementValue (pRecDevice pDevice, pRecElement pElement)
{
    IOReturn result = kIOReturnSuccess;
    IOHIDEventStruct hidEvent;
    hidEvent.value = 0;
    
    if (NULL != pDevice)
    {
        if (NULL != pElement)
        {
            if (NULL != pDevice->interface)
            {
                result = (*(IOHIDDeviceInterface **) pDevice->interface)->getElementValue (pDevice->interface, pElement->cookie, &hidEvent);
                if (kIOReturnSuccess != result)
                        HIDReportErrorNum ("Could not get HID element value via getElementValue.", result);
                // on 10.0.x this returns the incorrect result for negative ranges, so fix it!!!
                // this is not required on Mac OS X 10.1+
                if ((pElement->min < 0) && (hidEvent.value > pElement->max)) // assume range problem
                    hidEvent.value = hidEvent.value + pElement->min - pElement->max - 1;
            }
            else
                HIDReportError ("Did not have interface for device prior to getting element value.");
        }
        else
            HIDReportError ("Bad element passed to GetElementValue.");
    }
    else
        HIDReportError ("Bad device passed to GetElementValue.");
    // record min and max for auto scale and auto ...
    if (hidEvent.value < pElement->minReport)
        pElement->minReport = hidEvent.value; 
    if (hidEvent.value > pElement->maxReport)
        pElement->maxReport = hidEvent.value; 
 
    return hidEvent.value;
}


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