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/*FUNCTION<<qsort>>---sort an arrayINDEXqsortANSI_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 "global.h"#include "include/_ansi.h"#include "include/stdlib.h"#ifndef __GNUC__#define inline#endifstatic inline char *med3 _PARAMS((char *, char *, char *, int (*cmp)(const _PTR,const _PTR)));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 _ANDchar *b _ANDint n _ANDint swaptype){if(swaptype <= 1)swapcode(long, a, b, n)elseswapcode(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 _ANDchar *b _ANDchar *c _ANDint (*cmp)(const _PTR,const _PTR)){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 _ANDsize_t n _ANDsize_t es _ANDint (*cmp)(const _PTR,const _PTR)){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((unsigned int)(pd - pc), pn - pd - es);vecswap(pb, pn - r, r);if ((unsigned int)(r = pb - pa) > es)qsort(a, r / es, es, cmp);if ((unsigned int)(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);*/}