| 1 | /* $Id: memcmp.cpp 2981 2007-06-01 16:01:28Z vboxsync $ */
|
|---|
| 2 | /** @file
|
|---|
| 3 | * innotek Portable Runtime - CRT Strings, memcmp().
|
|---|
| 4 | */
|
|---|
| 5 |
|
|---|
| 6 | /*
|
|---|
| 7 | * Copyright (C) 2006-2007 innotek GmbH
|
|---|
| 8 | *
|
|---|
| 9 | * This file is part of VirtualBox Open Source Edition (OSE), as
|
|---|
| 10 | * available from http://www.virtualbox.org. This file is free software;
|
|---|
| 11 | * you can redistribute it and/or modify it under the terms of the GNU
|
|---|
| 12 | * General Public License as published by the Free Software Foundation,
|
|---|
| 13 | * in version 2 as it comes in the "COPYING" file of the VirtualBox OSE
|
|---|
| 14 | * distribution. VirtualBox OSE is distributed in the hope that it will
|
|---|
| 15 | * be useful, but WITHOUT ANY WARRANTY of any kind.
|
|---|
| 16 | *
|
|---|
| 17 | * If you received this file as part of a commercial VirtualBox
|
|---|
| 18 | * distribution, then only the terms of your commercial VirtualBox
|
|---|
| 19 | * license agreement apply instead of the previous paragraph.
|
|---|
| 20 | */
|
|---|
| 21 |
|
|---|
| 22 |
|
|---|
| 23 | /*******************************************************************************
|
|---|
| 24 | * Header Files *
|
|---|
| 25 | *******************************************************************************/
|
|---|
| 26 | #include <iprt/string.h>
|
|---|
| 27 | #include <iprt/types.h>
|
|---|
| 28 |
|
|---|
| 29 |
|
|---|
| 30 | /**
|
|---|
| 31 | * Copies a memory.
|
|---|
| 32 | *
|
|---|
| 33 | * @returns 0 if pvDst and pvSrc are equal
|
|---|
| 34 | * @returns <0 if pvDst is 'smaller' than pvSrc.
|
|---|
| 35 | * @returns >0 if pvDst is 'larger' than pvSrc.
|
|---|
| 36 | *
|
|---|
| 37 | * @param pvDst Pointer to the target block.
|
|---|
| 38 | * @param pvSrc Pointer to the source block.
|
|---|
| 39 | * @param cb The size of the block.
|
|---|
| 40 | */
|
|---|
| 41 | #ifdef _MSC_VER
|
|---|
| 42 | # if _MSC_VER >= 1400
|
|---|
| 43 | __checkReturn int __cdecl memcmp(__in_bcount_opt(_Size) const void * pvDst, __in_bcount_opt(_Size) const void * pvSrc, __in size_t cb)
|
|---|
| 44 | # else
|
|---|
| 45 | int memcmp(const void *pvDst, const void *pvSrc, size_t cb)
|
|---|
| 46 | # endif
|
|---|
| 47 | #else
|
|---|
| 48 | int memcmp(const void *pvDst, const void *pvSrc, size_t cb)
|
|---|
| 49 | #endif
|
|---|
| 50 | {
|
|---|
| 51 | register union
|
|---|
| 52 | {
|
|---|
| 53 | uint8_t const *pu8;
|
|---|
| 54 | uint32_t const *pu32;
|
|---|
| 55 | void const *pv;
|
|---|
| 56 | } uDst, uSrc;
|
|---|
| 57 | uDst.pv = pvDst;
|
|---|
| 58 | uSrc.pv = pvSrc;
|
|---|
| 59 |
|
|---|
| 60 | /* 32-bit word compare. */
|
|---|
| 61 | register size_t c = cb >> 2;
|
|---|
| 62 | while (c-- > 0)
|
|---|
| 63 | {
|
|---|
| 64 | /* ASSUMES int is at least 32-bit! */
|
|---|
| 65 | register int32_t iDiff = *uDst.pu32++ - *uSrc.pu32++;
|
|---|
| 66 | if (iDiff)
|
|---|
| 67 | return iDiff;
|
|---|
| 68 | }
|
|---|
| 69 |
|
|---|
| 70 | /* Remaining byte moves. */
|
|---|
| 71 | c = cb & 3;
|
|---|
| 72 | while (c-- > 0)
|
|---|
| 73 | {
|
|---|
| 74 | register int8_t iDiff = *uDst.pu8++ - *uSrc.pu8++;
|
|---|
| 75 | if (iDiff)
|
|---|
| 76 | return iDiff;
|
|---|
| 77 | }
|
|---|
| 78 |
|
|---|
| 79 | return 0;
|
|---|
| 80 | }
|
|---|
| 81 |
|
|---|
