106 lines
3.2 KiB
C
106 lines
3.2 KiB
C
/***
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*memmove.c - contains memmove routine
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*
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* Copyright (c) 1988-2001, Microsoft Corporation. All rights reserved.
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*
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*Purpose:
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* memmove() copies a source memory buffer to a destination buffer.
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* Overlapping buffers are treated specially, to avoid propogation.
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*
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*Revision History:
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* 05-31-89 JCR C version created.
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* 02-27-90 GJF Fixed calling type, #include <cruntime.h>, fixed
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* copyright.
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* 10-01-90 GJF New-style function declarator. Also, rewrote expr. to
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* avoid using cast as an lvalue.
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* 12-28-90 SRW Added cast of void * to char * for Mips C Compiler
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* 04-09-91 GJF Speed up a little for large buffers.
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* 08-06-91 GJF Backed out 04-09-91 change. Pointers would have to be
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* dword-aligned for this to work on MIPS.
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* 07-16-93 SRW ALPHA Merge
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* 09-01-93 GJF Merged NT SDK and Cuda versions.
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* 11-12-93 GJF Replace _MIPS_ and _ALPHA_ with _M_MRX000 and
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* _M_ALPHA (resp.).
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* 10-02-94 BWT Add function pragma for Alpha and PPC support
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* 10-07-97 RDL Added IA64.
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* 04-30-01 BWT Add AMD64.
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*
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*******************************************************************************/
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#include <cruntime.h>
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#include <string.h>
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/***
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*memmove - Copy source buffer to destination buffer
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*
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*Purpose:
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* memmove() copies a source memory buffer to a destination memory buffer.
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* This routine recognize overlapping buffers to avoid propogation.
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* For cases where propogation is not a problem, memcpy() can be used.
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*
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*Entry:
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* void *dst = pointer to destination buffer
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* const void *src = pointer to source buffer
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* size_t count = number of bytes to copy
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*
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*Exit:
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* Returns a pointer to the destination buffer
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*
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*Exceptions:
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*******************************************************************************/
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void * __cdecl memmove (
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void * dst,
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const void * src,
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size_t count
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)
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{
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void * ret = dst;
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#if defined(_M_IA64) || defined(_M_AMD64)
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{
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#if !defined(LIBCNTPR)
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__declspec(dllimport)
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#endif
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void RtlMoveMemory( void *, const void *, size_t count );
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RtlMoveMemory( dst, src, count );
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}
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#else
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if (dst <= src || (char *)dst >= ((char *)src + count)) {
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/*
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* Non-Overlapping Buffers
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* copy from lower addresses to higher addresses
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*/
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while (count--) {
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*(char *)dst = *(char *)src;
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dst = (char *)dst + 1;
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src = (char *)src + 1;
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}
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}
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else {
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/*
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* Overlapping Buffers
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* copy from higher addresses to lower addresses
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*/
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dst = (char *)dst + count - 1;
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src = (char *)src + count - 1;
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while (count--) {
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*(char *)dst = *(char *)src;
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dst = (char *)dst - 1;
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src = (char *)src - 1;
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}
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}
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#endif
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return(ret);
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}
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