iokit/Families/IOHIDSystem/IOHIDDescriptorParser/HIDIsButtonOrValue.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:           HIDIsButtonOrValue.c
  24
  25         Contains:       xxx put contents here xxx
  26
  27         Version:        xxx put version here xxx
  28
  29         Copyright:      © 1999 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                 (BWS)   Brent Schorsch
  42
  43         Change History (most recent first):
  44
  45           <USB3>         11/1/99        BWS             [2405720]  We need a better check for 'bit padding' items,
  46                                                                         rather than just is constant. We will check to make sure the
  47                                                                         item is constant, and has no usage, or zero usage.
  48           <USB2>          3/5/99        BWS             [2311366]  HIDIsButton should screen out constants (at least
  49                                                                         until other functions, like HIDGetButtons, are fixed to be able
  50                                                                         to properly skip constants)
  51           <USB1>          3/5/99        BWS             first checked in
  52 */
  53
  54 #include "HIDLib.h"
  55
  56 /*
  57  *-----------------------------------------------------------------------------
  58  *
  59  * HIDIsButton - Is the data button(s)?
  60  *
  61  *       Input:
  62  *                        ptReportItem                  - Input/Output/Feature
  63  *       Output:
  64  *       Returns:
  65  *                        Boolean
  66  *
  67  *-----------------------------------------------------------------------------
  68 */
  69 Boolean HIDIsButton(HIDReportItem *ptReportItem, HIDPreparsedDataRef preparsedDataRef)
  70 {
  71         HIDPreparsedDataPtr ptPreparsedData = (HIDPreparsedDataPtr) preparsedDataRef;
  72
  73 /*
  74  *      Disallow Null Pointers
  75 */
  76         if (ptReportItem==NULL)
  77                 return false;
  78 /*
  79  *      Remove items that are constant and have no usage
  80  */
  81         if ((ptReportItem->dataModes & kHIDDataConstantBit) == kHIDDataConstant)
  82         {
  83                 // if has no usages, then bit filler
  84                 if (ptReportItem->usageItemCount == 0)
  85                         return false;
  86
  87                 // also check to see if there is a usage, but it is zero
  88
  89                 // if the first usage item is range, then check that one
  90                 // (we will not worry about report items with multiple zero usages,
  91                 //  as I dont think that is a case that makes sense)
  92                 if (ptReportItem->firstUsageItem < ptPreparsedData->usageItemCount)
  93                 {
  94                         HIDP_UsageItem * ptUsageItem = &ptPreparsedData->usageItems[ptReportItem->firstUsageItem];
  95
  96                         // if it is a range usage, with both zero usages
  97                         if ((ptUsageItem->isRange && ptUsageItem->usageMinimum == 0 && ptUsageItem->usageMaximum == 0) &&
  98                                 // or not a range, and zero usage
  99                                 (!ptUsageItem->isRange && ptUsageItem->usage == 0))
 100                                 // then this is bit filler
 101                                 return false;
 102                 }
 103         }
 104
 105 /*
 106  *      Arrays and 1-bit Variables
 107 */
 108         return (((ptReportItem->dataModes & kHIDDataArrayBit) == kHIDDataArray)
 109            || (ptReportItem->globals.reportSize == 1));
 110 }
 111
 112 /*
 113  *-----------------------------------------------------------------------------
 114  *
 115  * HIDIsVariable - Is the data variable(s)?
 116  *
 117  *       Input:
 118  *                        ptReportItem                  - Input/Output/Feature
 119  *       Output:
 120  *       Returns:
 121  *                        Boolean
 122  *
 123  *-----------------------------------------------------------------------------
 124 */
 125 Boolean HIDIsVariable(HIDReportItem *ptReportItem, HIDPreparsedDataRef preparsedDataRef)
 126 {
 127         HIDPreparsedDataPtr ptPreparsedData = (HIDPreparsedDataPtr) preparsedDataRef;
 128
 129 /*
 130  *      Disallow Null Pointers
 131 */
 132         if (ptReportItem==NULL)
 133                 return false;
 134
 135 /*
 136  *      Remove items that are constant and have no usage
 137  */
 138         if ((ptReportItem->dataModes & kHIDDataConstantBit) == kHIDDataConstant)
 139         {
 140                 // if has no usages, then bit filler
 141                 if (ptReportItem->usageItemCount == 0)
 142                         return false;
 143
 144                 // also check to see if there is a usage, but it is zero
 145
 146                 // if the first usage item is range, then check that one
 147                 // (we will not worry about report items with multiple zero usages,
 148                 //  as I dont think that is a case that makes sense)
 149                 if (ptReportItem->firstUsageItem < ptPreparsedData->usageItemCount)
 150                 {
 151                         HIDP_UsageItem * ptUsageItem = &ptPreparsedData->usageItems[ptReportItem->firstUsageItem];
 152
 153                         // if it is a range usage, with both zero usages
 154                         if ((ptUsageItem->isRange && ptUsageItem->usageMinimum == 0 && ptUsageItem->usageMaximum == 0) &&
 155                                 // or not a range, and zero usage
 156                                 (!ptUsageItem->isRange && ptUsageItem->usage == 0))
 157                                 // then this is bit filler
 158                                 return false;
 159                 }
 160         }
 161
 162 /*
 163  *      Multi-bit Variables
 164 */
 165         return (((ptReportItem->dataModes & kHIDDataArrayBit) != kHIDDataArray)
 166            && (ptReportItem->globals.reportSize != 1));
 167 }