HIDGetButtonsOnPage.c   [plain text]

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 *
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 *
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 *
 * @APPLE_LICENSE_HEADER_END@
 */

/*
	File:		HIDGetButtonsOnPage.c
*/

#include "HIDLib.h"

/*
 *------------------------------------------------------------------------------
 *
 * HIDGetButtonsOnPage - Get the state of the buttons for a Page
 *
 *	 Input:
 *			  reportType		   - HIDP_Input, HIDP_Output, HIDP_Feature
 *			  usagePage			   - Page Criteria or zero
 *			  iCollection			- Collection Criteria or zero
 *			  piUsageList			- Usages for pressed buttons
 *			  piUsageListLength		- Max entries in UsageList
 *			  ptPreparsedData		- Pre-Parsed Data
 *			  psReport				- An HID Report
 *			  iReportLength			- The length of the Report
 *	 Output:
 *			  piValue				- Pointer to usage Value
 *	 Returns:
 *
 *------------------------------------------------------------------------------
*/
OSStatus HIDGetButtonsOnPage(HIDReportType reportType,
						   HIDUsage usagePage,
						   UInt32 iCollection,
						   HIDUsage *piUsageList,
						   UInt32 *piUsageListLength,
						   HIDPreparsedDataRef preparsedDataRef,
						   void *psReport,
						   UInt32 iReportLength)
{
	HIDPreparsedDataPtr ptPreparsedData = (HIDPreparsedDataPtr) preparsedDataRef;
	HIDUsageAndPage tUsageAndPage;
	HIDCollection *ptCollection;
	HIDReportItem *ptReportItem;
	OSStatus iStatus;
	int iR, iE;
	long iValue;
	int iStart;
	int iMaxUsages;
	int iReportItem;
	Boolean bIncompatibleReport = false;
	Boolean butNotReally = false;
/*
 *	Disallow Null Pointers
*/
	if ((ptPreparsedData == NULL)
	 || (piUsageList == NULL)
	 || (piUsageListLength == NULL)
	 || (psReport == NULL))
		return kHIDNullPointerErr;
	if (ptPreparsedData->hidTypeIfValid != kHIDOSType)
		return kHIDInvalidPreparsedDataErr;
/*
 *	The Collection must be in range
*/
	if ((iCollection < 0) || (iCollection >= ptPreparsedData->collectionCount))
		return kHIDBadParameterErr;
/*
 *	Save the size of the list
*/
	iMaxUsages = *piUsageListLength;
	*piUsageListLength = 0;
/*
 *	Search only the scope of the Collection specified
 *	Go through the ReportItems
 *	Filter on ReportType and usagePage
*/
	ptCollection = &ptPreparsedData->collections[iCollection];
	for (iR=0; iR<ptCollection->reportItemCount; iR++)
	{
		iReportItem = ptCollection->firstReportItem + iR;
		ptReportItem = &ptPreparsedData->reportItems[iReportItem];
		if (HIDIsButton(ptReportItem, preparsedDataRef))
		{
/*
 *			This may be the proper data to get
 *			Let's check for the proper Report ID, Type, and Length
*/
			iStatus = HIDCheckReport(reportType,preparsedDataRef,ptReportItem,
									   psReport,iReportLength);
/*
 *			The Report ID or Type may not match.
 *			This may not be an error (yet)
*/
			if (iStatus == kHIDIncompatibleReportErr)
				bIncompatibleReport = true;
			else if (iStatus != kHIDSuccess)
				return iStatus;
			else
			{
				butNotReally = true;
/*
 *				Save Array Buttons
*/
				iStart = ptReportItem->startBit;
				for (iE=0; iE<ptReportItem->globals.reportCount; iE++)
				{
					if ((ptReportItem->dataModes & kHIDDataArrayBit) == kHIDDataArray)
					{
						iStatus = HIDGetData(psReport, iReportLength, iStart,
									 ptReportItem->globals.reportSize,
									 &iValue, false);
						if (!iStatus)
							iStatus = HIDPostProcessRIValue (ptReportItem, &iValue);
						HIDUsageAndPageFromIndex(preparsedDataRef,
									 ptReportItem,
									 iValue-ptReportItem->globals.logicalMinimum,
									 &tUsageAndPage);
						iStart += ptReportItem->globals.reportSize;
						if (usagePage == tUsageAndPage.usagePage)
						{
							if (*piUsageListLength >= iMaxUsages)
								return kHIDBufferTooSmallErr;
							piUsageList[(*piUsageListLength)++] = iValue;
						}
					}
/*
 *					Save Bitmapped Buttons
*/
					else
					{
						iStatus = HIDGetData(psReport, iReportLength, iStart, 1, &iValue, false);
						if (!iStatus)
							iStatus = HIDPostProcessRIValue (ptReportItem, &iValue);
						iStart++;
						if (!iStatus && iValue != 0)
						{
							HIDUsageAndPageFromIndex(preparsedDataRef,ptReportItem,iE,&tUsageAndPage);
							if (usagePage == tUsageAndPage.usagePage)
							{
								if (*piUsageListLength >= iMaxUsages)
									return kHIDBufferTooSmallErr;
								piUsageList[(*piUsageListLength)++] = tUsageAndPage.usage;
							}
						}
					}
				}
			}
		}
	}
/*
 *	If nothing was returned then change the status
*/
	if (*piUsageListLength == 0)
	{
		// If any of the report items were not the right type, we have set the bIncompatibleReport flag.
		// However, if any of the report items really were the correct type, we have done our job of checking
		// and really didn't find a usage. Don't let the bIncompatibleReport flag wipe out our valid test.
		if (bIncompatibleReport && !butNotReally)
			return kHIDIncompatibleReportErr;
		return kHIDUsageNotFoundErr;
	}
	return kHIDSuccess;
}