/*FUNCTION<<qsort>>---sort an arrayINDEX	qsortANSI_SYNOPSIS	#include <stdlib.h>	void qsort(void *<[base]>, size_t <[nmemb]>, size_t <[size]>,		   int (*<[compar]>)(const void *, const void *) );TRAD_SYNOPSIS	#include <stdlib.h>	qsort(<[base]>, <[nmemb]>, <[size]>, <[compar]> )	char *<[base]>;	size_t <[nmemb]>;	size_t <[size]>;	int (*<[compar]>)();DESCRIPTION<<qsort>> 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 argumentshown as <[compar]>.  (This permits sorting objects of unknownproperties.)  Define the comparison function to accept two arguments,each a pointer to an element of the array starting at <[base]>.  Theresult of <<(*<[compar]>)>> must be negative if the first argument isless than the second, zero if the two arguments match, and positive ifthe 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 <<qsort>> returns, thearray elements beginning at <[base]> have been reordered.RETURNS<<qsort>> does not return a result.PORTABILITY<<qsort>> 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 <stdlib.h>#ifndef __GNUC__#define inline#endifstatic 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);*/}