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/*

FUNCTION

<>---sort an array

INDEX

	qsort

ANSI_SYNOPSIS

	#include 

	void qsort(void *<[base]>, size_t <[nmemb]>, size_t <[size]>,

		   int (*<[compar]>)(const void *, const void *) );

TRAD_SYNOPSIS

	#include 

	qsort(<[base]>, <[nmemb]>, <[size]>, <[compar]> )

	char *<[base]>;

	size_t <[nmemb]>;

	size_t <[size]>;

	int (*<[compar]>)();

DESCRIPTION

<> sorts an array (beginning at <[base]>) of <[nmemb]> objects.

<[size]> describes the size of each element of the array.

You must supply a pointer to a comparison function, using the argument

shown as <[compar]>.  (This permits sorting objects of unknown

properties.)  Define the comparison function to accept two arguments,

each a pointer to an element of the array starting at <[base]>.  The

result of <<(*<[compar]>)>> must be negative if the first argument is

less than the second, zero if the two arguments match, and positive if

the first argument is greater than the second (where ``less than'' and

``greater than'' refer to whatever arbitrary ordering is appropriate).

The array is sorted in place; that is, when <> returns, the

array elements beginning at <[base]> have been reordered.

RETURNS

<> does not return a result.

PORTABILITY

<> is required by ANSI (without specifying the sorting algorithm).

*/

/*-

 * Copyright (c) 1992, 1993

 *	The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *	This product includes software developed by the University of

 *	California, Berkeley and its contributors.

 * 4. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <_ansi.h>

#include 

#ifndef __GNUC__

#define inline

#endif

static inline char	*med3 _PARAMS((char *, char *, char *, int (*)()));

static inline void	 swapfunc _PARAMS((char *, char *, int, int));

#define min(a, b)	(a) < (b) ? a : b

/*

 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".

 */

#define swapcode(TYPE, parmi, parmj, n) { 		\

	long i = (n) / sizeof (TYPE); 			\

	register TYPE *pi = (TYPE *) (parmi); 		\

	register TYPE *pj = (TYPE *) (parmj); 		\

	do { 						\

		register TYPE	t = *pi;		\

		*pi++ = *pj;				\

		*pj++ = t;				\

        } while (--i > 0);				\

}

#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \

	es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;

static inline void

_DEFUN(swapfunc, (a, b, n, swaptype),

	char *a _AND

	char *b _AND

	int n _AND

	int swaptype)

{

	if(swaptype <= 1)

		swapcode(long, a, b, n)

	else

		swapcode(char, a, b, n)

}

#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)

static inline char *

_DEFUN(med3, (a, b, c, cmp),

	char *a _AND

	char *b _AND

	char *c _AND

	int (*cmp)())

{

	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 ));

}

void

_DEFUN(qsort, (a, n, es, cmp),

	void *a _AND

	size_t n _AND

	size_t es _AND

	int (*cmp)())

{

	char *pa, *pb, *pc, *pd, *pl, *pm, *pn;

	int d, r, swaptype, swap_cnt;

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 = 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) {  /* Switch to insertion sort */

		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 - es);

	vecswap(pb, pn - r, r);

	if ((r = pb - pa) > es)

		qsort(a, r / es, es, cmp);

	if ((r = pd - pc) > es) {

		/* Iterate rather than recurse to save stack space */

		a = pn - r;

		n = r / es;

		goto loop;

	}

/*		qsort(pn - r, r / es, es, cmp);*/

}