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/***
*memmove.c - contains memmove routine
*
* Copyright (c) 1988-1991, Microsoft Corporation. All right reserved.
*
*Purpose:
* memmove() copies a source memory buffer to a destination buffer.
* Overlapping buffers are treated specially, to avoid propogation.
*
*Revision History:
* 05-31-89 JCR C version created.
* 02-27-90 GJF Fixed calling type, #include <cruntime.h>, fixed
* copyright.
* 10-01-90 GJF New-style function declarator. Also, rewrote expr. to
* avoid using cast as an lvalue.
* 12-28-90 SRW Added cast of void * to char * for Mips C Compiler
* 04-09-91 GJF Speed up a little for large buffers.
* 08-06-91 GJF Backed out 04-09-91 change. Pointers would have to be
* dword-aligned for this to work on MIPS.
* 07-16-93 SRW ALPHA Merge
*
*******************************************************************************/
#include <cruntime.h>
#include <string.h>
#if defined(_M_ALPHA)
#pragma function(memmove)
#endif
/***
*memmove - Copy source buffer to destination buffer
*
*Purpose:
* memmove() copies a source memory buffer to a destination memory buffer.
* This routine recognize overlapping buffers to avoid propogation.
* For cases where propogation is not a problem, memcpy() can be used.
*
*Entry:
* void *dst = pointer to destination buffer
* const void *src = pointer to source buffer
* size_t count = number of bytes to copy
*
*Exit:
* Returns a pointer to the destination buffer
*
*Exceptions:
*******************************************************************************/
void * _CALLTYPE1 memmove (
void * dst,
const void * src,
size_t count
)
{
void * ret = dst;
#if defined(_M_MRX000) || defined(_M_ALPHA) || defined(_M_PPC)
{
extern void RtlMoveMemory( void *, const void *, size_t count );
RtlMoveMemory( dst, src, count );
}
#else
if (dst <= src || (char *)dst >= ((char *)src + count)) {
/*
* Non-Overlapping Buffers
* copy from lower addresses to higher addresses
*/
while (count--) {
*(char *)dst = *(char *)src;
dst = (char *)dst + 1;
src = (char *)src + 1;
}
}
else {
/*
* Overlapping Buffers
* copy from higher addresses to lower addresses
*/
dst = (char *)dst + count - 1;
src = (char *)src + count - 1;
while (count--) {
*(char *)dst = *(char *)src;
dst = (char *)dst - 1;
src = (char *)src - 1;
}
}
#endif
return(ret);
}
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