strcpy

#include "stdafx.h"
#include <stdio.h>
/* fast strcpy -- Copyright (C) 2003 Thomas M. Ogrisegg <[email protected]> */
//#include <string.h>
//#include "dietfeatures.h"
//#include "dietstring.h"
// ----following are dietstring.h content.
//#include <endian.h>
//# define MKW(x) (x|x<<8|x<<16|x<<24)
int MKW(int x)
{
	x = x | x<<8 | x << 16 | x << 24;
	return x;
}

//# define STRALIGN(x) (((unsigned long)x&3)?4-((unsigned long)x&3):0)
unsigned long STRALIGN(unsigned long xPtr)
{
	unsigned long xRet = (unsigned long)xPtr & 3;
	if (xRet)
		xRet = 4 - ((unsigned long) xPtr & 3);
	else
		xRet = 0;
	return xRet;
}

/* GFC(x)    - returns first character */
/* INCSTR(x) - moves to next character */
# define GFC(x) ((x)&0xff)
# define INCSTR(x) do { x >>= 8; } while (0)

//#define UNALIGNED(x,y) (((unsigned long)x & (sizeof (unsigned long)-1)) ^ ((unsigned long)y & (sizeof (unsigned long)-1)))
unsigned long MyUnaligned(unsigned long xPtr, unsigned long yPtr)
{
	unsigned long valN1 = sizeof (unsigned long)-1;
	unsigned long xVal = (unsigned long) xPtr & valN1;
	unsigned long yVal = (unsigned long) yPtr & valN1;
	unsigned long retVal = xVal ^ yVal;
	return retVal;
}
// ----above are dietstring.h content.

char *
strcpy2 (char *s1, const char *s2)
{
    char           *res = s1;
    int             tmp;
    unsigned long   l;

    if (MyUnaligned((unsigned long)s1, (unsigned long)s2)){
		while ((*s1++ = *s2++));
		return (res);
    }

    if ((tmp = STRALIGN((unsigned long)s1))){
		while (tmp-- && (*s1++ = *s2++));
		if (tmp != -1) return (res);
    }

    while (1) {
		unsigned long key1 = MKW(0x1ul);
		unsigned long key2 = MKW(0x80ul);

		l = *(const unsigned long *) s2;

		if (((l - key1) & ~l) & key2) {
			while ((*s1++ = GFC(l))) INCSTR(l);
			return (res);
		}
		
		*(unsigned long *) s1 = l;
		s2 += sizeof(unsigned long);
		s1 += sizeof(unsigned long);
	}
}

int _tmain(int argc, _TCHAR* argv[])
{
	char* p = (char*)malloc(50* sizeof p);
	char* str = "aaaabbbbbcccccc";
	strcpy2(p, str);
	free(p);
	return 0;
}