/* * @APPLE_LICENSE_HEADER_START@ * * Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved. * * This file contains Original Code and/or Modifications of Original Code * as defined in and that are subject to the Apple Public Source License * Version 2.0 (the 'License'). You may not use this file except in * compliance with the License. Please obtain a copy of the License at * http://www.opensource.apple.com/apsl/ and read it before using this * file. * * The 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, QUIET ENJOYMENT OR NON-INFRINGEMENT. * Please see the License for the specific language governing rights and * limitations under the License. * * @APPLE_LICENSE_HEADER_END@ */ /* File: HIDNextItem.c Contains: xxx put contents here xxx Version: xxx put version here xxx Copyright: © 1999 by Apple Computer, Inc., all rights reserved. File Ownership: DRI: xxx put dri here xxx Other Contact: xxx put other contact here xxx Technology: xxx put technology here xxx Writers: (DF) David Ferguson (JRH) Rhoads Hollowell (BWS) Brent Schorsch Change History (most recent first): <USB4> 11/3/99 DF And now I get to add the code to actually fix the checkin below. <USB3> 11/1/99 BWS Fix long item calc error, fix by Dave Ferguson <USB2> 6/1/99 JRH Get rid of an uninitialized variable warning. It turns out that with the code flow it was never being used before being initialized, but the compiler was complaining. <USB1> 3/5/99 BWS first checked in */ #include "HIDLib.h" /* *----------------------------------------------------------------------------- * * HIDNextItem - Get the Next Item * * Input: * ptDescriptor - Descriptor Structure * Output: * ptItem - Caller-provided Item Structure * Returns: * kHIDSuccess - Success * kHIDEndOfDescriptorErr - End of the HID Report Descriptor * *----------------------------------------------------------------------------- */ OSStatus HIDNextItem(HIDReportDescriptor *ptDescriptor) { HIDItem *ptItem; unsigned char iHeader; unsigned char *psD; int i; int iLength; UInt32 *piX; int iSize; int iByte = 0; /* * Disallow Null Pointers */ if (ptDescriptor==NULL) return kHIDNullPointerErr; /* * Use local pointers */ ptItem = &ptDescriptor->item; psD = ptDescriptor->descriptor; piX = &ptDescriptor->index; iLength = ptDescriptor->descriptorLength; /* * Don't go past the end of the buffer */ if (*piX >= iLength) return kHIDEndOfDescriptorErr; /* * Get the header byte */ iHeader = psD[(*piX)++]; /* * Don't go past the end of the buffer */ if (*piX > iLength) return kHIDEndOfDescriptorErr; ptItem->itemType = iHeader; ptItem->itemType &= kHIDItemTypeMask; ptItem->itemType >>= kHIDItemTypeShift; /* * Long Item Header * Skip Long Items! */ if (iHeader==kHIDLongItemHeader) { iSize = psD[(*piX)++]; ptItem->tag = *piX++; } /* * Short Item Header */ else { iSize = iHeader; iSize &= kHIDItemSizeMask; if (iSize==3) iSize = 4; ptItem->byteCount = iSize; ptItem->tag = iHeader; ptItem->tag &= kHIDItemTagMask; ptItem->tag >>= kHIDItemTagShift; } /* * Don't go past the end of the buffer */ if ((*piX + iSize) > iLength) return kHIDEndOfDescriptorErr; /* * Pick up the data */ ptItem->unsignedValue = 0; if (iSize==0) { ptItem->signedValue = 0; return kHIDSuccess; } /* * Get the data bytes */ for (i = 0; i < iSize; i++) { iByte = psD[(*piX)++]; ptItem->unsignedValue |= (iByte << (i*8)); } /* * Keep one value unsigned */ ptItem->signedValue = ptItem->unsignedValue; /* * Sign extend one value */ if ((iByte & 0x80) != 0) { while (i < sizeof(int)) ptItem->signedValue |= (0xFF << ((i++)*8)); } return kHIDSuccess; }