Source to iokit/Families/IOHIDSystem/IOHIDDescriptorParser/HIDProcessReportItem.c

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 * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
 *
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 * 
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/*
	File:		HIDProcessReportItem.c

	Contains:	xxx put contents here xxx

	Version:	xxx put version here xxx

	Copyright:	� 1999 by Apple Computer, Inc., all rights reserved.

	File Ownership:

		DRI:				xxx put dri here xxx

		Other Contact:		xxx put other contact here xxx

		Technology:			xxx put technology here xxx

	Writers:

		(BWS)	Brent Schorsch

	Change History (most recent first):

	  <USB7>	  4/7/99	BWS		Add support for reversed report items
	  <USB6>	 3/20/99	BWS		Oops, strict error checking does not work if there is no error.
									We should only return error if it is not noErr
	  <USB5>	 3/17/99	BWS		[2314839]  Added flags field to HIDPreparsedData which is set in
									new parameter to HIDOpenReportDescriptor. We check the
									StrictErrorCheck bit to determine whether we return errors or
									just try to work around problems we find
	  <USB4>	  3/7/99	BWS		[2311413]  Do not error check min/max ranges for constants
	  <USB3>	  3/7/99	BWS		[2311412]  We need to handle the cases where physical min/max is
									either (0/0) which is valid according to the spec, and means to
									use the logical min/max, and the invalid case, that some devices
									exibit, which has (0/-1) which we will treat the same,
	  <USB2>	  3/5/99	BWS		[2311359]  HIDProcessReportItem does not initialize startBit
									field of HIDReportItem!
	  <USB1>	  3/5/99	BWS		first checked in
*/

#include "HIDLib.h"

/*
 *------------------------------------------------------------------------------
 *
 * HIDProcessReportItem - Process a Report Item MainItem
 *
 *	 Input:
 *			  ptDescriptor			- The Descriptor Structure
 *			  ptPreparsedData		- The PreParsedData Structure
 *	 Output:
 *			  ptDescriptor			- The Descriptor Structure
 *			  ptPreparsedData		- The PreParsedData Structure
 *	 Returns:
 *			  kHIDSuccess		   - Success
 *			  kHIDNullPointerErr	  - Argument, Pointer was Null
 *
 *------------------------------------------------------------------------------
*/
OSStatus HIDProcessReportItem(HIDReportDescriptor *ptDescriptor, HIDPreparsedDataPtr ptPreparsedData)
{
	OSStatus error = noErr;
	HIDReportItem *ptReportItem;
	HIDReportSizes *ptReport;
	int iBits;
/*
 *	Disallow NULL Pointers
*/

	if ((ptDescriptor == NULL) || (ptPreparsedData == NULL))
		return kHIDNullPointerErr;
/*
 *	Begin to initialize the new Report Item structure
*/

	ptReportItem = &ptPreparsedData->reportItems[ptPreparsedData->reportItemCount++];
	ptReportItem->dataModes = ptDescriptor->item.unsignedValue;
	ptReportItem->globals = ptDescriptor->globals;
	ptReportItem->flags = 0;
	
/*
 *	Reality Check on the Report Main Item
*/
	// Don't check ranges for constants (MS Sidewinder, for one, does not reset)
	//if (!(ptReportItem->dataModes & kHIDDataConstantBit)) // don't think we need this anymore
	{
		if (ptReportItem->globals.logicalMinimum >= (1<<ptReportItem->globals.reportSize))
		{
			error = kHIDBadLogicalMinimumErr;
			ptReportItem->globals.logicalMinimum = 0;
		}
		if (ptReportItem->globals.logicalMaximum >= (1<<ptReportItem->globals.reportSize))
		{
			if (error == noErr)
				error = kHIDBadLogicalMaximumErr;
			ptReportItem->globals.logicalMaximum = (1<<ptReportItem->globals.reportSize);
		}
		if (ptReportItem->globals.logicalMinimum > ptReportItem->globals.logicalMaximum)
		{
			SInt32	temp;
			if (error == noErr)
				error = kHIDInvertedLogicalRangeErr;
			
			// mark as a 'reversed' item
			ptReportItem->flags |= kHIDReportItemFlag_Reversed;
			
			temp = ptReportItem->globals.logicalMaximum;
			ptReportItem->globals.logicalMaximum = ptReportItem->globals.logicalMinimum;
			ptReportItem->globals.logicalMinimum = temp;
		}
	}
	
	// check to see if we got half a range (we don't need to fix this, since 'isRange' will be false
	if ((error == noErr) && (ptDescriptor->haveUsageMin || ptDescriptor->haveUsageMax))
		error = kHIDUnmatchedUsageRangeErr;
	if ((error == noErr) && (ptDescriptor->haveStringMin || ptDescriptor->haveStringMax))
		error = kHIDUnmatchedStringRangeErr;
	if ((error == noErr) && (ptDescriptor->haveDesigMin || ptDescriptor->haveDesigMax))
		error = kHIDUnmatchedDesignatorRangeErr;
	
	// if the physical min/max are out of wack, use the logical values
	if (ptReportItem->globals.physicalMinimum >= ptReportItem->globals.physicalMaximum)
	{
		// equal to each other is not an error, just means to use the logical values
		if ((error == noErr) && 
			(ptReportItem->globals.physicalMinimum > ptReportItem->globals.physicalMaximum))
			error = kHIDInvertedPhysicalRangeErr;

		ptReportItem->globals.physicalMinimum = ptReportItem->globals.logicalMinimum;
		ptReportItem->globals.physicalMaximum = ptReportItem->globals.logicalMaximum;
	}
	
	// if strict error checking is true, return any errors
	if (error != noErr && ptPreparsedData->flags & kHIDFlag_StrictErrorChecking)
		return error;
	
/*
 *	Continue to initialize the new Report Item structure
*/

	ptReportItem->parent = ptDescriptor->parent;
	ptReportItem->firstUsageItem = ptDescriptor->firstUsageItem;
	ptDescriptor->firstUsageItem = ptPreparsedData->usageItemCount;
	ptReportItem->usageItemCount = ptPreparsedData->usageItemCount - ptReportItem->firstUsageItem;
	ptReportItem->firstStringItem = ptDescriptor->firstStringItem;
	ptDescriptor->firstStringItem = ptPreparsedData->stringItemCount;
	ptReportItem->stringItemCount = ptPreparsedData->stringItemCount - ptReportItem->firstStringItem;
	ptReportItem->firstDesigItem = ptDescriptor->firstDesigItem;
	ptDescriptor->firstDesigItem = ptPreparsedData->desigItemCount;
	ptReportItem->desigItemCount = ptPreparsedData->desigItemCount - ptReportItem->firstDesigItem;
/*
 *	Update the Report by the size of this item
*/

	ptReport = &ptPreparsedData->reports[ptReportItem->globals.reportIndex];
	iBits = ptReportItem->globals.reportSize * ptReportItem->globals.reportCount;
	switch (ptDescriptor->item.tag)
	{
		case kHIDTagFeature:
			ptReportItem->reportType = kHIDFeatureReport;
            ptReportItem->startBit = ptReport->featureBitCount;
			ptReport->featureBitCount += iBits;
			break;
		case kHIDTagOutput:
			ptReportItem->reportType = kHIDOutputReport;
            ptReportItem->startBit = ptReport->outputBitCount;
			ptReport->outputBitCount += iBits;
			break;
		case kHIDTagInput:
			ptReportItem->reportType = kHIDInputReport;
            ptReportItem->startBit = ptReport->inputBitCount;
			ptReport->inputBitCount += iBits;
			break;
		default:
			ptReportItem->reportType = kHIDUnknownReport;
            ptReportItem->startBit = 0;
			break;
	}
	return kHIDSuccess;
}