iokit/Families/IOHIDSystem/IOHIDDescriptorParser/HIDGetNextUsageValueInfo.c

   1 /*
   2  * Copyright (c) 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:           HIDGetNextUsageValueInfo.c
  24
  25         Contains:       HIDGetNextUsageValueInfo call for HID Library
  26
  27         Version:        1.0d1
  28
  29         Copyright:      © 2000 by Apple Computer, Inc., all rights reserved.
  30
  31         File Ownership:
  32
  33                 DRI:                            David Ferguson
  34
  35                 Other Contact:          Keithen Hayenga
  36
  37                 Technology:                     technologies, usb
  38
  39         Writers:
  40
  41                 (KH)    Keithen Hayenga
  42
  43         Change History (most recent first):
  44
  45           <USB1>         2/14/00        KH              first checked in
  46 */
  47
  48 #include "HIDLib.h"
  49
  50 /*
  51  *------------------------------------------------------------------------------
  52  *
  53  * HIDGetNextUsageValueInfo - Get report id and collection for a usage. In keeping
  54  *                                                              with USBGetNextInterface, we find the usage in the
  55  *                                                              next collection, so that you can find usages that
  56  *                                                              have the same usage and usage page.
  57  *
  58  *       Input:
  59  *                        reportType                    - HIDP_Input, HIDP_Output, HIDP_Feature
  60  *                        usagePage                             - Page Criteria or zero
  61  *                        usage                                 - The usage to get the information for
  62  *                        collection                    - Starting Collection Criteria or zero
  63  *                        preparsedDataRef              - Pre-Parsed Data
  64  *       Output:
  65  *                        collection                    - Final Collection Criteria or no change
  66  *                        reportID                              - Report ID or no change
  67  *       Returns:
  68  *                        kHIDBadParameterErr when there are no more collections to search.
  69  *
  70  *------------------------------------------------------------------------------
  71 */
  72 OSStatus HIDGetNextUsageValueInfo
  73                    (HIDReportType                       reportType,
  74                         HIDUsage                                usagePage,
  75                         HIDUsage                                usage,
  76                         UInt32 *                                collection,
  77                         UInt8 *                                 reportID,
  78                         HIDPreparsedDataRef             preparsedDataRef)
  79 {
  80         HIDPreparsedDataPtr ptPreparsedData = (HIDPreparsedDataPtr)preparsedDataRef;
  81         HIDReportItem *ptReportItem;
  82         UInt32 iCollection;
  83         UInt32 newCollection = 0xFFFFFFFF;
  84         int iR;
  85         UInt8 newReportID = 0;
  86         OSStatus iStatus = kHIDUsageNotFoundErr;
  87
  88         //Disallow Null Pointers
  89
  90         if ((ptPreparsedData == NULL) || (collection == NULL) || (reportID == NULL))
  91                 return kHIDNullPointerErr;
  92         if (ptPreparsedData->hidTypeIfValid != kHIDOSType)
  93                 return kHIDInvalidPreparsedDataErr;
  94
  95         // The Collection must be in range
  96
  97         iCollection = *collection;
  98         // Umm... an unsigned number can never be less than 0!
  99         if ((iCollection < 0) || (iCollection >= ptPreparsedData->collectionCount))
 100                 return kHIDBadParameterErr;
 101
 102         // HIDGetNextUsageValueInfo is different from HIDGetUsageValue in how it treats
 103         // the collection parameter. HIDGetUsageValue will only look at report items that
 104         // are within the collection and can therefore limit it's searches to starting at
 105         // ptPreparsedData->collections[iCollection]->firstReportItem and only check
 106         // ptPreparsedData->collections[iCollection]->reportItemCount. Since we want to
 107         // find the NEXT collection as well, we need to cycle through all of the reports.
 108
 109         for (iR = 0; iR < ptPreparsedData->reportItemCount; iR++)
 110         {
 111                 SInt32 minUsage;
 112                 SInt32 maxUsage;
 113                 HIDP_UsageItem thisUsage;
 114
 115                 ptReportItem = &ptPreparsedData->reportItems[iR];
 116
 117                 thisUsage = ptPreparsedData->usageItems[ptReportItem->firstUsageItem];
 118
 119                 if (thisUsage.isRange)
 120                 {
 121                         minUsage = thisUsage.usageMinimum;
 122                         maxUsage = thisUsage.usageMaximum;
 123                 }
 124                 else
 125                 {
 126                         minUsage = thisUsage.usage;
 127                         maxUsage = thisUsage.usage;
 128                 }
 129
 130                 if (ptReportItem->reportType == reportType &&
 131                         (usagePage == 0 || ptReportItem->globals.usagePage == usagePage) &&
 132                         (usage >= minUsage && usage <= maxUsage) &&
 133                         ptReportItem->parent > iCollection &&
 134                         HIDIsVariable(ptReportItem, preparsedDataRef))
 135                 {
 136                         if (ptReportItem->parent < newCollection)
 137                         {
 138                                 newCollection = ptReportItem->parent;
 139                                 newReportID = iR;
 140                                 iStatus = noErr;
 141                         }
 142                 }
 143         }
 144
 145         if (iStatus == noErr)
 146         {
 147                 *reportID = newReportID;
 148                 *collection = newCollection;
 149         }
 150
 151         return iStatus;
 152 }
 153