iokit/Families/IOHIDSystem/IOHIDDescriptorParser/HIDUsageListDifference.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:           HIDUsageListDifference.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           <USB1>          3/5/99        BWS             first checked in
  46 */
  47
  48 #include "HIDLib.h"
  49
  50 /*
  51  *------------------------------------------------------------------------------
  52  *
  53  * In - Is a usage in a UsageList?
  54  *
  55  *       Input:
  56  *                        piUsageList                   - usage List
  57  *                        iUsageListLength              - Max entries in usage Lists
  58  *                        usage                            - The usage
  59  *       Output:
  60  *       Returns: true or false
  61  *
  62  *------------------------------------------------------------------------------
  63 */
  64 static Boolean IsUsageInUsageList(HIDUsage *piUsageList, UInt32 iUsageListLength, HIDUsage usage)
  65 {
  66         unsigned int i;
  67         for (i = 0; i < iUsageListLength; i++)
  68                 if (piUsageList[i] == usage)
  69                         return true;
  70         return false;
  71 }
  72
  73 /*
  74  *------------------------------------------------------------------------------
  75  *
  76  * HIDUsageListDifference - Return adds and drops given present and past
  77  *
  78  *       Input:
  79  *                        piPreviouUL                   - Previous usage List
  80  *                        piCurrentUL                   - Current usage List
  81  *                        piBreakUL                             - Break usage List
  82  *                        piMakeUL                              - Make usage List
  83  *                        iUsageListLength              - Max entries in usage Lists
  84  *       Output:
  85  *                        piBreakUL                             - Break usage List
  86  *                        piMakeUL                              - Make usage List
  87  *       Returns:
  88  *
  89  *------------------------------------------------------------------------------
  90 */
  91 OSStatus HIDUsageListDifference(HIDUsage *piPreviousUL, HIDUsage *piCurrentUL, HIDUsage *piBreakUL, HIDUsage *piMakeUL, UInt32 iUsageListLength)
  92 {
  93         int i;
  94         HIDUsage usage;
  95         int iBreakLength=0;
  96         int iMakeLength=0;
  97         for (i = 0; i < iUsageListLength; i++)
  98         {
  99 /*
 100  *              If in Current but not Previous then it's a Make
 101 */
 102                 usage = piCurrentUL[i];
 103                 if ((usage != 0) && (!IsUsageInUsageList(piPreviousUL,iUsageListLength,usage))
 104                                                   && (!IsUsageInUsageList(piMakeUL,iMakeLength,usage)))
 105                         piMakeUL[iMakeLength++] = usage;
 106 /*
 107  *              If in Previous but not Current then it's a Break
 108 */
 109                 usage = piPreviousUL[i];
 110                 if ((usage != 0) && (!IsUsageInUsageList(piCurrentUL,iUsageListLength,usage))
 111                                                   && (!IsUsageInUsageList(piBreakUL,iBreakLength,usage)))
 112                         piBreakUL[iBreakLength++] = usage;
 113         }
 114 /*
 115  *      Clear the rest of the usage Lists
 116 */
 117         while (iMakeLength < iUsageListLength)
 118                 piMakeUL[iMakeLength++] = 0;
 119         while (iBreakLength < iUsageListLength)
 120                 piBreakUL[iBreakLength++] = 0;
 121         return kHIDSuccess;
 122 }