1/*
2 * Copyright (c) 1992, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. Neither the name of the University nor the names of its contributors
14 *    may be used to endorse or promote products derived from this software
15 *    without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30#include "yportenv.h"
31//#include <linux/string.h>
32
33/*
34 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
35 */
36#define swapcode(TYPE, parmi, parmj, n) { 		\
37	long i = (n) / sizeof (TYPE); 			\
38	register TYPE *pi = (TYPE *) (parmi); 		\
39	register TYPE *pj = (TYPE *) (parmj); 		\
40	do { 						\
41		register TYPE	t = *pi;		\
42		*pi++ = *pj;				\
43		*pj++ = t;				\
44        } while (--i > 0);				\
45}
46
47#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
48	es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
49
50static __inline void
51swapfunc(char *a, char *b, int n, int swaptype)
52{
53	if (swaptype <= 1)
54		swapcode(long, a, b, n)
55	else
56		swapcode(char, a, b, n)
57}
58
59#define swap(a, b)					\
60	if (swaptype == 0) {				\
61		long t = *(long *)(a);			\
62		*(long *)(a) = *(long *)(b);		\
63		*(long *)(b) = t;			\
64	} else						\
65		swapfunc(a, b, es, swaptype)
66
67#define vecswap(a, b, n) 	if ((n) > 0) swapfunc(a, b, n, swaptype)
68
69static __inline char *
70med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
71{
72	return cmp(a, b) < 0 ?
73	       (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
74              :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
75}
76
77#define min(a,b) (((a) < (b)) ? (a) : (b))
78void
79qsort(void *aa, size_t n, size_t es, int (*cmp)(const void *, const void *))
80{
81	char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
82	int d, r, swaptype, swap_cnt;
83	register char *a = aa;
84
85loop:	SWAPINIT(a, es);
86	swap_cnt = 0;
87	if (n < 7) {
88		for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
89			for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
90			     pl -= es)
91				swap(pl, pl - es);
92		return;
93	}
94	pm = (char *)a + (n / 2) * es;
95	if (n > 7) {
96		pl = (char *)a;
97		pn = (char *)a + (n - 1) * es;
98		if (n > 40) {
99			d = (n / 8) * es;
100			pl = med3(pl, pl + d, pl + 2 * d, cmp);
101			pm = med3(pm - d, pm, pm + d, cmp);
102			pn = med3(pn - 2 * d, pn - d, pn, cmp);
103		}
104		pm = med3(pl, pm, pn, cmp);
105	}
106	swap(a, pm);
107	pa = pb = (char *)a + es;
108
109	pc = pd = (char *)a + (n - 1) * es;
110	for (;;) {
111		while (pb <= pc && (r = cmp(pb, a)) <= 0) {
112			if (r == 0) {
113				swap_cnt = 1;
114				swap(pa, pb);
115				pa += es;
116			}
117			pb += es;
118		}
119		while (pb <= pc && (r = cmp(pc, a)) >= 0) {
120			if (r == 0) {
121				swap_cnt = 1;
122				swap(pc, pd);
123				pd -= es;
124			}
125			pc -= es;
126		}
127		if (pb > pc)
128			break;
129		swap(pb, pc);
130		swap_cnt = 1;
131		pb += es;
132		pc -= es;
133	}
134	if (swap_cnt == 0) {  /* Switch to insertion sort */
135		for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
136			for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
137			     pl -= es)
138				swap(pl, pl - es);
139		return;
140	}
141
142	pn = (char *)a + n * es;
143	r = min(pa - (char *)a, pb - pa);
144	vecswap(a, pb - r, r);
145	r = min((long)(pd - pc), (long)(pn - pd - es));
146	vecswap(pb, pn - r, r);
147	if ((r = pb - pa) > es)
148		qsort(a, r / es, es, cmp);
149	if ((r = pd - pc) > es) {
150		/* Iterate rather than recurse to save stack space */
151		a = pn - r;
152		n = r / es;
153		goto loop;
154	}
155/*		qsort(pn - r, r / es, es, cmp);*/
156}
157