windows-xp/Source/XPSP1/NT/enduser/netmeeting/ui/conf/memmove.cpp

#include "precomp.h"

// In debug mode, we link with CRT, so we don't need this!
#ifndef _DEBUG


	/***
	*memmove.c - contains memmove routine
	*
	*       Copyright (c) 1988-1997, Microsoft Corporation. All right reserved.
	*
	*Purpose:
	*       memmove() copies a source memory buffer to a destination buffer.
	*       Overlapping buffers are treated specially, to avoid propogation.
	*
	*******************************************************************************/

	#if defined (_M_ALPHA)
	#pragma function(memmove)
	#endif  /* defined (_M_ALPHA) */

	/***
	*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 * __cdecl 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  /* defined (_M_MRX000) || defined (_M_ALPHA) || defined (_M_PPC) */
			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  /* defined (_M_MRX000) || defined (_M_ALPHA) || defined (_M_PPC) */

			return(ret);
	}

#endif // !_DEBUG