/***
*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.
*
*******************************************************************************/

/***
*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:
*******************************************************************************/
#include <_size_t.h>

void *memmove(void *dst, const void *src, size_t count)
{
	void *ret = dst;


	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;
		}
	}

	return ret;
}
