#include <stdlib.h>
#include <string.h>

#define swapcode(TYPE, parmi, parmj, n) {	\
	long i = (n) / sizeof (TYPE);			\
	TYPE *pi = (TYPE *) (parmi);			\
	TYPE *pj = (TYPE *) (parmj);			\
	do {									\
		TYPE	t = *pi;					\
		*pi++ = *pj;						\
		*pj++ = t;							\
        } while (--i > 0);					\
}

#define swap(a, b)							\
	if (swaptype == 0) {					\
		long t = *(long *)(a);				\
		*(long *)(a) = *(long *)(b);		\
		*(long *)(b) = t;					\
	} else									\
		swapfunc(a, b, es, swaptype)

#define vecswap(a, b, n)					\
	if ((n) > 0)							\
		swapfunc(a, b, n, swaptype)

#define SWAPINIT(a, es)						\
	swaptype = ((char *)a - (char *)0) % sizeof(long) || es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;

static __inline char * med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
{
	return cmp(a, b) < 0 ?
			(cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a)) :
			(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c));
}

static __inline void swapfunc(char *a, char *b, int n, int swaptype)
{
	if (swaptype <= 1)
		swapcode(long, a, b, n)
	else
		swapcode(char, a, b, n)
}

void qsort(void * aa, size_t n, size_t es, int (*cmp)(const void *, const void *))
{
	char * pa, * pb, * pc, * pd, * pl, * pm, * pn;
	int d, r, swaptype, swap_cnt;
	char * a = aa;

loop:
	SWAPINIT(a, es);
	swap_cnt = 0;
	if(n < 7)
	{
		for(pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
			for(pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; pl -= es)
				swap(pl, pl - es);
		return;
	}
	pm = (char *)a + (n / 2) * es;
	if(n > 7)
	{
		pl = (char *)a;
		pn = (char *)a + (n - 1) * es;
		if(n > 40)
		{
			d = (n / 8) * es;
			pl = med3(pl, pl + d, pl + 2 * d, cmp);
			pm = med3(pm - d, pm, pm + d, cmp);
			pn = med3(pn - 2 * d, pn - d, pn, cmp);
		}
		pm = med3(pl, pm, pn, cmp);
	}
	swap(a, pm);
	pa = pb = (char *)a + es;

	pc = pd = (char *)a + (n - 1) * es;
	for(;;)
	{
		while(pb <= pc && (r = cmp(pb, a)) <= 0)
		{
			if(r == 0)
			{
				swap_cnt = 1;
				swap(pa, pb);
				pa += es;
			}
			pb += es;
		}
		while(pb <= pc && (r = cmp(pc, a)) >= 0)
		{
			if(r == 0)
			{
				swap_cnt = 1;
				swap(pc, pd);
				pd -= es;
			}
			pc -= es;
		}
		if(pb > pc)
			break;
		swap(pb, pc);
		swap_cnt = 1;
		pb += es;
		pc -= es;
	}
	if(swap_cnt == 0)
	{
		for(pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
			for(pl = pm; pl > (char *)a && cmp(pl - es, pl) > 0; pl -= es)
				swap(pl, pl - es);
		return;
	}

	pn = (char *)a + n * es;
	r = min(pa - (char * )a, pb - pa);
	vecswap(a, pb - r, r);
	r = min(pd - pc, pn - pd - (int )es);
	vecswap(pb, pn - r, r);
	if((r = pb - pa) > (int)es)
		qsort(a, r / es, es, cmp);
	if((r = pd - pc) > (int)es)
	{
		a = pn - r;
		n = r / es;
		goto loop;
	}
}