[apple/libc.git] / stdlib / qsort.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
 * 
 * This file contains Original Code and/or Modifications of Original Code
 * as defined in and that are subject to the Apple Public Source License
 * Version 2.0 (the 'License'). You may not use this file except in
 * compliance with the License. Please obtain a copy of the License at
 * http://www.opensource.apple.com/apsl/ and read it before using this
 * file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
 * Please see the License for the specific language governing rights and
 * limitations under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*
 * 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 <sys/types.h>
#include <stdlib.h>

static inline char	*med3 __P((char *, char *, char *, int (*)()));
static inline void	 swapfunc __P((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
swapfunc(a, b, n, swaptype)
	char *a, *b;
	int n, 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 *
med3(a, b, c, cmp)
	char *a, *b, *c;
	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
qsort(a, n, es, cmp)
	void *a;
	size_t n, es;
	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 = 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 = a + (n / 2) * es;
	if (n > 7) {
		pl = a;
		pn = 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 = a + es;

	pc = pd = 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 = 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 = 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);*/
}
Commit	Line	Data
e9ce8d39 A	1	/*
	2	* Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
	3	*
	4	* @APPLE_LICENSE_HEADER_START@
	5	*
734aad71	6	* Copyright (c) 1999-2003 Apple Computer, Inc. All Rights Reserved.
e9ce8d39	7	*
734aad71 A	8	* This file contains Original Code and/or Modifications of Original Code
	9	* as defined in and that are subject to the Apple Public Source License
	10	* Version 2.0 (the 'License'). You may not use this file except in
	11	* compliance with the License. Please obtain a copy of the License at
	12	* http://www.opensource.apple.com/apsl/ and read it before using this
	13	* file.
	14	*
	15	* The Original Code and all software distributed under the License are
	16	* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
e9ce8d39 A	17	* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
e9ce8d39 A	18	* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
734aad71 A	19	* FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
	20	* Please see the License for the specific language governing rights and
	21	* limitations under the License.
e9ce8d39 A	22	*
	23	* @APPLE_LICENSE_HEADER_END@
	24	*/
	25	/*
	26	* Copyright (c) 1992, 1993
	27	* The Regents of the University of California. All rights reserved.
	28	*
	29	* Redistribution and use in source and binary forms, with or without
	30	* modification, are permitted provided that the following conditions
	31	* are met:
	32	* 1. Redistributions of source code must retain the above copyright
	33	* notice, this list of conditions and the following disclaimer.
	34	* 2. Redistributions in binary form must reproduce the above copyright
	35	* notice, this list of conditions and the following disclaimer in the
	36	* documentation and/or other materials provided with the distribution.
	37	* 3. All advertising materials mentioning features or use of this software
	38	* must display the following acknowledgement:
	39	* This product includes software developed by the University of
	40	* California, Berkeley and its contributors.
	41	* 4. Neither the name of the University nor the names of its contributors
	42	* may be used to endorse or promote products derived from this software
	43	* without specific prior written permission.
	44	*
	45	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	46	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	47	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	48	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	49	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	50	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	51	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	52	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	53	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	54	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	55	* SUCH DAMAGE.
	56	*/
	57
	58
	59	#include <sys/types.h>
	60	#include <stdlib.h>
	61
	62	static inline char med3 __P((char , char , char , int (*)()));
	63	static inline void swapfunc __P((char , char , int, int));
	64
	65	#define min(a, b) (a) < (b) ? a : b
	66
	67	/*
	68	* Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
	69	*/
	70	#define swapcode(TYPE, parmi, parmj, n) { \
	71	long i = (n) / sizeof (TYPE); \
	72	register TYPE pi = (TYPE ) (parmi); \
	73	register TYPE pj = (TYPE ) (parmj); \
	74	do { \
	75	register TYPE t = *pi; \
	76	pi++ = pj; \
	77	*pj++ = t; \
	78	} while (--i > 0); \
	79	}
	80
	81	#define SWAPINIT(a, es) swaptype = ((char )a - (char )0) % sizeof(long) \|\| \
	82	es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
	83
	84	static inline void
	85	swapfunc(a, b, n, swaptype)
86	char a, b;
87	int n, swaptype;
88	{
89	if(swaptype <= 1)
90	swapcode(long, a, b, n)
91	else
92	swapcode(char, a, b, n)
93	}
94
95	#define swap(a, b) \
96	if (swaptype == 0) { \
97	long t = (long )(a); \
98	(long )(a) = (long )(b); \
99	(long )(b) = t; \
100	} else \
101	swapfunc(a, b, es, swaptype)
102
103	#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
104
105	static inline char *
106	med3(a, b, c, cmp)
107	char a, b, *c;
108	int (*cmp)();
109	{
110	return cmp(a, b) < 0 ?
111	(cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
112	:(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
113	}
114
115	void
116	qsort(a, n, es, cmp)
117	void *a;
118	size_t n, es;
119	int (*cmp)();
120	{
121	char pa, pb, pc, pd, pl, pm, *pn;
122	int d, r, swaptype, swap_cnt;
123
124	loop: SWAPINIT(a, es);
125	swap_cnt = 0;
126	if (n < 7) {
127	for (pm = a + es; pm < (char ) a + n es; pm += es)
128	for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
129	pl -= es)
130	swap(pl, pl - es);
131	return;
132	}
133	pm = a + (n / 2) * es;
134	if (n > 7) {
135	pl = a;
136	pn = a + (n - 1) * es;
137	if (n > 40) {
138	d = (n / 8) * es;
139	pl = med3(pl, pl + d, pl + 2 * d, cmp);
140	pm = med3(pm - d, pm, pm + d, cmp);
141	pn = med3(pn - 2 * d, pn - d, pn, cmp);
142	}
143	pm = med3(pl, pm, pn, cmp);
144	}
145	swap(a, pm);
146	pa = pb = a + es;
147
148	pc = pd = a + (n - 1) * es;
149	for (;;) {
150	while (pb <= pc && (r = cmp(pb, a)) <= 0) {
151	if (r == 0) {
152	swap_cnt = 1;
153	swap(pa, pb);
154	pa += es;
155	}
156	pb += es;
157	}
158	while (pb <= pc && (r = cmp(pc, a)) >= 0) {
159	if (r == 0) {
160	swap_cnt = 1;
161	swap(pc, pd);
162	pd -= es;
163	}
164	pc -= es;
165	}
166	if (pb > pc)
167	break;
168	swap(pb, pc);
169	swap_cnt = 1;
170	pb += es;
171	pc -= es;
172	}
173	if (swap_cnt == 0) { /* Switch to insertion sort */
174	for (pm = a + es; pm < (char ) a + n es; pm += es)
175	for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
176	pl -= es)
177	swap(pl, pl - es);
178	return;
179	}
180
181	pn = a + n * es;
182	r = min(pa - (char *)a, pb - pa);
183	vecswap(a, pb - r, r);
184	r = min(pd - pc, pn - pd - es);
185	vecswap(pb, pn - r, r);
186	if ((r = pb - pa) > es)
187	qsort(a, r / es, es, cmp);
188	if ((r = pd - pc) > es) {
189	/* Iterate rather than recurse to save stack space */
190	a = pn - r;
191	n = r / es;
192	goto loop;
193	}
194	/* qsort(pn - r, r / es, es, cmp);*/
195	}