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 * 4. 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#if 0
31#if defined(LIBC_SCCS) && !defined(lint)
32static char sccsid[] = "@(#)qsort.c	8.1 (Berkeley) 6/4/93";
33#endif /* LIBC_SCCS and not lint */
34#include <sys/cdefs.h>
35__FBSDID("$FreeBSD$");
36#endif
37
38#include <config.h>
39
40#ifdef NEED_QSORT
41
42#include "roken.h"
43
44#include <stdlib.h>
45
46#ifdef I_AM_QSORT_R
47typedef int		 cmp_t(void *, const void *, const void *);
48#else
49typedef int		 cmp_t(const void *, const void *);
50#endif
51static inline char	*med3(char *, char *, char *, cmp_t *, void *);
52static inline void	 swapfunc(char *, char *, int, int);
53
54/*
55 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
56 */
57#define swapcode(TYPE, parmi, parmj, n) { 		\
58	long i = (n) / sizeof (TYPE); 			\
59	TYPE *pi = (TYPE *) (parmi); 		\
60	TYPE *pj = (TYPE *) (parmj); 		\
61	do { 						\
62		TYPE	t = *pi;		\
63		*pi++ = *pj;				\
64		*pj++ = t;				\
65        } while (--i > 0);				\
66}
67
68#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
69	es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
70
71static inline void
72swapfunc(a, b, n, swaptype)
73	char *a, *b;
74	int n, swaptype;
75{
76	if(swaptype <= 1)
77		swapcode(long, a, b, n)
78	else
79		swapcode(char, a, b, n)
80}
81
82#define swap(a, b)					\
83	if (swaptype == 0) {				\
84		long t = *(long *)(a);			\
85		*(long *)(a) = *(long *)(b);		\
86		*(long *)(b) = t;			\
87	} else						\
88		swapfunc(a, b, es, swaptype)
89
90#define vecswap(a, b, n) 	if ((n) > 0) swapfunc(a, b, n, swaptype)
91
92#ifdef I_AM_QSORT_R
93#define	CMP(t, x, y) (cmp((t), (x), (y)))
94#else
95#define	CMP(t, x, y) (cmp((x), (y)))
96#endif
97
98static inline char *
99med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
100#ifndef I_AM_QSORT_R
101/* __unused */
102#endif
103)
104{
105	return CMP(thunk, a, b) < 0 ?
106	       (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
107              :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
108}
109
110#ifdef I_AM_QSORT_R
111void
112rk_qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
113#else
114#define thunk NULL
115void
116rk_qsort(void *a, size_t n, size_t es, cmp_t *cmp)
117#endif
118{
119	char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
120	size_t d, r;
121	int cmp_result;
122	int swaptype, swap_cnt;
123
124loop:	SWAPINIT(a, es);
125	swap_cnt = 0;
126	if (n < 7) {
127		for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
128			for (pl = pm;
129			     pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
130			     pl -= es)
131				swap(pl, pl - es);
132		return;
133	}
134	pm = (char *)a + (n / 2) * es;
135	if (n > 7) {
136		pl = a;
137		pn = (char *)a + (n - 1) * es;
138		if (n > 40) {
139			d = (n / 8) * es;
140			pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
141			pm = med3(pm - d, pm, pm + d, cmp, thunk);
142			pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
143		}
144		pm = med3(pl, pm, pn, cmp, thunk);
145	}
146	swap(a, pm);
147	pa = pb = (char *)a + es;
148
149	pc = pd = (char *)a + (n - 1) * es;
150	for (;;) {
151		while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
152			if (cmp_result == 0) {
153				swap_cnt = 1;
154				swap(pa, pb);
155				pa += es;
156			}
157			pb += es;
158		}
159		while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
160			if (cmp_result == 0) {
161				swap_cnt = 1;
162				swap(pc, pd);
163				pd -= es;
164			}
165			pc -= es;
166		}
167		if (pb > pc)
168			break;
169		swap(pb, pc);
170		swap_cnt = 1;
171		pb += es;
172		pc -= es;
173	}
174	if (swap_cnt == 0) {  /* Switch to insertion sort */
175		for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
176			for (pl = pm;
177			     pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
178			     pl -= es)
179				swap(pl, pl - es);
180		return;
181	}
182
183	pn = (char *)a + n * es;
184	r = min(pa - (char *)a, pb - pa);
185	vecswap(a, pb - r, r);
186	r = min(pd - pc, pn - pd - es);
187	vecswap(pb, pn - r, r);
188	if ((r = pb - pa) > es)
189#ifdef I_AM_QSORT_R
190		rk_qsort_r(a, r / es, es, thunk, cmp);
191#else
192		rk_qsort(a, r / es, es, cmp);
193#endif
194	if ((r = pd - pc) > es) {
195		/* Iterate rather than recurse to save stack space */
196		a = pn - r;
197		n = r / es;
198		goto loop;
199	}
200/*		rk_qsort(pn - r, r / es, es, cmp);*/
201}
202
203#endif /* NEED_QSORT */
204