iokit/Families/IOHIDSystem/IOHIDDescriptorParser/HIDHasUsage.c

   1 /*
   2  * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23         File:           HIDHasUsage.c
  24
  25         Contains:       xxx put contents here xxx
  26
  27         Version:        xxx put version here xxx
  28
  29         Copyright:      © 1999-2000 by Apple Computer, Inc., all rights reserved.
  30
  31         File Ownership:
  32
  33                 DRI:                            xxx put dri here xxx
  34
  35                 Other Contact:          xxx put other contact here xxx
  36
  37                 Technology:                     xxx put technology here xxx
  38
  39         Writers:
  40
  41                 (KH)    Keithen Hayenga
  42                 (BWS)   Brent Schorsch
  43
  44         Change History (most recent first):
  45
  46           <USB2>        12/12/00        KH              range count off by 1.
  47           <USB1>          3/5/99        BWS             first checked in
  48 */
  49
  50 #include "HIDLib.h"
  51
  52 /*
  53  *------------------------------------------------------------------------------
  54  *
  55  * HidP_UsageFromIndex
  56  *
  57  *       Input:
  58  *                        ptPreparsedData               - The Preparsed Data
  59  *                        ptReportItem                  - The Report Item
  60  *                        usagePage                        - The usage Page to find
  61  *                        usage                            - The usage to find
  62  *                        piIndex(optional)             - The usage Index pointer (Can be used to tell
  63  *                                                                              which bits in an array correspond to that usage.)
  64  *                        piCount(optional)             - The usage Count pointer (Can be used to tell
  65  *                                                                              how many items will be in a report.)
  66  *       Output:
  67  *                        piIndex                               - The usage Index
  68  *       Returns:
  69  *                        The usage
  70  *
  71  *------------------------------------------------------------------------------
  72 */
  73 Boolean HIDHasUsage (HIDPreparsedDataRef preparsedDataRef,
  74                                            HIDReportItem *ptReportItem,
  75                                            HIDUsage usagePage, HIDUsage usage,
  76                                            UInt32 *piIndex, UInt32 *piCount)
  77 {
  78         HIDPreparsedDataPtr ptPreparsedData = (HIDPreparsedDataPtr) preparsedDataRef;
  79         int iUsageItem;
  80         UInt32 iUsageIndex;
  81         int iUsages;
  82         int i;
  83         UInt32 iCountsLeft;
  84         HIDP_UsageItem *ptUsageItem;
  85         Boolean bOnPage;
  86 /*
  87  *      Disallow Null Pointers
  88 */
  89         if ((ptPreparsedData == NULL)
  90          || (ptReportItem == NULL))
  91                 return 0;
  92         if (ptPreparsedData->hidTypeIfValid != kHIDOSType)
  93                 return 0;
  94 /*
  95  *      Look through the usage Items for this usage
  96 */
  97         iUsageItem = ptReportItem->firstUsageItem;
  98         iUsageIndex = 0;
  99         for (i=0; i<ptReportItem->usageItemCount; i++)
 100         {
 101 /*
 102  *         Each usage Item is either a usage or a usage range
 103 */
 104                 ptUsageItem = &ptPreparsedData->usageItems[iUsageItem++];
 105                 bOnPage = ((usagePage == 0) || (usagePage == ptUsageItem->usagePage));
 106                 if (ptUsageItem->isRange)
 107                 {
 108 /*
 109  *                      For usage Ranges
 110  *                        If the index is in the range
 111  *                              then return the usage
 112  *                        Otherwise adjust the index by the size of the range
 113 */
 114                         if ((usage >= ptUsageItem->usageMinimum)
 115                          && (usage <= ptUsageItem->usageMaximum))
 116                         {
 117                                 if (piIndex != NULL)
 118                                         *piIndex = iUsageIndex + (ptUsageItem->usageMinimum - usage);
 119 /*
 120  *                              If this usage is the last one for this ReportItem
 121  *                                then it gets all of the remaining reportCount
 122 */
 123                                 if (piCount != NULL)
 124                                 {
 125                                         // piCount is going to be used to find which element in a button array is
 126                                         // the one that returns the value for that usage.
 127                                         if (((i+1) == ptReportItem->usageItemCount)
 128                                          && (usage == ptUsageItem->usageMaximum))
 129                                         {
 130                                                 // Hmm, the same logic in the non-range case below was wrong. But things
 131                                                 // seem to be working for finding buttons, so i am not changing it here.
 132                                                 // However, we have made some changes to range calculations that may no
 133                                                 // longer require that -1 here either. Heads up!
 134                                                 iCountsLeft = ptReportItem->globals.reportCount - iUsageIndex - 1;
 135                                                 if (iCountsLeft > 1)
 136                                                         *piCount = iCountsLeft;
 137                                                 else
 138                                                         *piCount = 1;
 139                                         }
 140                                         else
 141                                                 *piCount = 1;
 142                                 }
 143                                 if (bOnPage)
 144                                         return true;
 145                         }
 146                         iUsages = ptUsageItem->usageMaximum - ptUsageItem->usageMinimum;
 147                         if (iUsages < 0)
 148                                 iUsages = -iUsages;
 149                         iUsages++;              // Add off by one adjustment AFTER sign correction.
 150                         iUsageIndex += iUsages;
 151                 }
 152                 else
 153                 {
 154 /*
 155  *                      For Usages
 156  *                      If the index is zero
 157  *                        then return this usage
 158  *                      Otherwise one less to index through
 159 */
 160                         if (usage == ptUsageItem->usage)
 161                         {
 162                                 if (piIndex != NULL)
 163                                         *piIndex = iUsageIndex;
 164                                 if (piCount != NULL)
 165                                 {
 166                                         if ((i+1) == ptReportItem->usageItemCount)
 167                                         {
 168                                                 // Keithen does not understand the logic of iCountsLeft.
 169                                                 // In Radar #2579612 we come through here for HIDGetUsageValueArray
 170                                                 // and HIDGetSpecificValueCaps. In both cases piCount that is returned
 171                                                 // should be the reportCount without the -1.
 172 //                                              iCountsLeft = ptReportItem->globals.reportCount - iUsageIndex - 1;
 173                                                 iCountsLeft = ptReportItem->globals.reportCount - iUsageIndex;
 174                                                 if (iCountsLeft > 1)
 175                                                         *piCount = iCountsLeft;
 176                                                 else
 177                                                    *piCount = 1;
 178                                         }
 179                                         else
 180                                                 *piCount = 1;
 181                                 }
 182                                 if (bOnPage)
 183                                         return true;
 184                         }
 185                         iUsageIndex++;
 186                 }
 187         }
 188         return false;
 189 }