[redis.git] / pqsort.c

/* The following is the NetBSD libc qsort implementation modified in order to
 * support partial sorting of ranges for Redis.
 *
 * Copyright(C) 2009 Salvatore Sanfilippo. All rights reserved.
 *
 * The original copyright notice follows. */


/*	$NetBSD: qsort.c,v 1.19 2009/01/30 23:38:44 lukem Exp $	*/

/*-
 * 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. 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/cdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)qsort.c	8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: qsort.c,v 1.19 2009/01/30 23:38:44 lukem Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include <sys/types.h>

#include <assert.h>
#include <errno.h>
#include <stdlib.h>

static inline char	*med3 __P((char *, char *, char *,
    int (*)(const void *, const void *)));
static inline void	 swapfunc __P((char *, char *, size_t, 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) { 		\
	size_t i = (n) / sizeof (TYPE); 		\
	TYPE *pi = (TYPE *)(void *)(parmi); 		\
	TYPE *pj = (TYPE *)(void *)(parmj); 		\
	do { 						\
		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(char *a, char *b, size_t n, 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 *)(void *)(a);			\
		*(long *)(void *)(a) = *(long *)(void *)(b);	\
		*(long *)(void *)(b) = t;			\
	} else							\
		swapfunc(a, b, es, swaptype)

#define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype)

static inline char *
med3(char *a, char *b, char *c,
    int (*cmp) __P((const void *, const void *)))
{

	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 ));
}

static void
_pqsort(void *a, size_t n, size_t es,
    int (*cmp) __P((const void *, const void *)), void *lrange, void *rrange)
{
	char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
	size_t d, r;
	int swaptype, swap_cnt, cmp_result;

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 = (char *) 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 && (cmp_result = cmp(pb, a)) <= 0) {
			if (cmp_result == 0) {
				swap_cnt = 1;
				swap(pa, pb);
				pa += es;
			}
			pb += es;
		}
		while (pb <= pc && (cmp_result = cmp(pc, a)) >= 0) {
			if (cmp_result == 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((size_t)(pd - pc), pn - pd - es);
	vecswap(pb, pn - r, r);
	if ((r = pb - pa) > es) {
                void *_l = a, *_r = ((unsigned char*)a)+r-1;
                if (!((lrange < _l && rrange < _l) ||
                    (lrange > _r && rrange > _r)))
		    _pqsort(a, r / es, es, cmp, lrange, rrange);
        }
	if ((r = pd - pc) > es) { 
                void *_l, *_r;
                
		/* Iterate rather than recurse to save stack space */
		a = pn - r;
		n = r / es;

                _l = a;
                _r = ((unsigned char*)a)+r-1;
                if (!((lrange < _l && rrange < _l) ||
                    (lrange > _r && rrange > _r)))
		    goto loop;
	}
/*		qsort(pn - r, r / es, es, cmp);*/
}

void
pqsort(void *a, size_t n, size_t es,
    int (*cmp) __P((const void *, const void *)), size_t lrange, size_t rrange)
{
    _pqsort(a,n,es,cmp,((unsigned char*)a)+(lrange*es),
                       ((unsigned char*)a)+((rrange+1)*es)-1);
}
Commit	Line	Data
75fd597d	1	/* The following is the NetBSD libc qsort implementation modified in order to
	2	* support partial sorting of ranges for Redis.
	3	*
	4	* Copyright(C) 2009 Salvatore Sanfilippo. All rights reserved.
	5	*
	6	* The original copyright notice follows. */
	7
	8
	9	/* $NetBSD: qsort.c,v 1.19 2009/01/30 23:38:44 lukem Exp $ */
	10
	11	/*-
	12	* Copyright (c) 1992, 1993
	13	* The Regents of the University of California. All rights reserved.
	14	*
	15	* Redistribution and use in source and binary forms, with or without
	16	* modification, are permitted provided that the following conditions
	17	* are met:
	18	* 1. Redistributions of source code must retain the above copyright
	19	* notice, this list of conditions and the following disclaimer.
	20	* 2. Redistributions in binary form must reproduce the above copyright
	21	* notice, this list of conditions and the following disclaimer in the
	22	* documentation and/or other materials provided with the distribution.
	23	* 3. Neither the name of the University nor the names of its contributors
	24	* may be used to endorse or promote products derived from this software
	25	* without specific prior written permission.
	26	*
	27	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	28	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	29	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	30	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	31	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	32	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	33	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	34	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	35	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	36	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	37	* SUCH DAMAGE.
	38	*/
	39
	40	#include <sys/cdefs.h>
	41	#if defined(LIBC_SCCS) && !defined(lint)
	42	#if 0
	43	static char sccsid[] = "@(#)qsort.c 8.1 (Berkeley) 6/4/93";
	44	#else
	45	__RCSID("$NetBSD: qsort.c,v 1.19 2009/01/30 23:38:44 lukem Exp $");
	46	#endif
	47	#endif /* LIBC_SCCS and not lint */
	48
	49	#include <sys/types.h>
	50
	51	#include <assert.h>
	52	#include <errno.h>
	53	#include <stdlib.h>
	54
	55	static inline char med3 __P((char , char , char ,
	56	int ()(const void , const void *)));
	57	static inline void swapfunc __P((char , char , size_t, int));
	58
	59	#define min(a, b) (a) < (b) ? a : b
	60
	61	/*
	62	* Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
	63	*/
	64	#define swapcode(TYPE, parmi, parmj, n) { \
65	size_t i = (n) / sizeof (TYPE); \
66	TYPE pi = (TYPE )(void *)(parmi); \
67	TYPE pj = (TYPE )(void *)(parmj); \
68	do { \
69	TYPE t = *pi; \
70	pi++ = pj; \
71	*pj++ = t; \
72	} while (--i > 0); \
73	}
74
75	#define SWAPINIT(a, es) swaptype = ((char )a - (char )0) % sizeof(long) \|\| \
76	es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
77
78	static inline void
79	swapfunc(char a, char b, size_t n, int swaptype)
80	{
81
82	if (swaptype <= 1)
83	swapcode(long, a, b, n)
84	else
85	swapcode(char, a, b, n)
86	}
87
88	#define swap(a, b) \
89	if (swaptype == 0) { \
90	long t = (long )(void *)(a); \
91	(long )(void )(a) = (long )(void )(b); \
92	(long )(void *)(b) = t; \
93	} else \
94	swapfunc(a, b, es, swaptype)
95
96	#define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype)
97
98	static inline char *
99	med3(char a, char b, char *c,
100	int (cmp) __P((const void , const void *)))
101	{
102
103	return cmp(a, b) < 0 ?
104	(cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
105	:(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
106	}
107
108	static void
109	_pqsort(void *a, size_t n, size_t es,
110	int (cmp) __P((const void , const void )), void lrange, void *rrange)
111	{
112	char pa, pb, pc, pd, pl, pm, *pn;
113	size_t d, r;
114	int swaptype, swap_cnt, cmp_result;
115
116	loop: SWAPINIT(a, es);
117	swap_cnt = 0;
118	if (n < 7) {
119	for (pm = (char ) a + es; pm < (char ) a + n * es; pm += es)
120	for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
121	pl -= es)
122	swap(pl, pl - es);
123	return;
124	}
125	pm = (char ) a + (n / 2) es;
126	if (n > 7) {
127	pl = (char *) a;
128	pn = (char ) a + (n - 1) es;
129	if (n > 40) {
130	d = (n / 8) * es;
131	pl = med3(pl, pl + d, pl + 2 * d, cmp);
132	pm = med3(pm - d, pm, pm + d, cmp);
133	pn = med3(pn - 2 * d, pn - d, pn, cmp);
134	}
135	pm = med3(pl, pm, pn, cmp);
136	}
137	swap(a, pm);
138	pa = pb = (char *) a + es;
139
140	pc = pd = (char ) a + (n - 1) es;
141	for (;;) {
142	while (pb <= pc && (cmp_result = cmp(pb, a)) <= 0) {
143	if (cmp_result == 0) {
144	swap_cnt = 1;
145	swap(pa, pb);
146	pa += es;
147	}
148	pb += es;
149	}
150	while (pb <= pc && (cmp_result = cmp(pc, a)) >= 0) {
151	if (cmp_result == 0) {
152	swap_cnt = 1;
153	swap(pc, pd);
154	pd -= es;
155	}
156	pc -= es;
157	}
158	if (pb > pc)
159	break;
160	swap(pb, pc);
161	swap_cnt = 1;
162	pb += es;
163	pc -= es;
164	}
165	if (swap_cnt == 0) { /* Switch to insertion sort */
166	for (pm = (char ) a + es; pm < (char ) a + n * es; pm += es)
167	for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
168	pl -= es)
169	swap(pl, pl - es);
170	return;
171	}
172
173	pn = (char ) a + n es;
174	r = min(pa - (char *) a, pb - pa);
175	vecswap(a, pb - r, r);
176	r = min((size_t)(pd - pc), pn - pd - es);
177	vecswap(pb, pn - r, r);
178	if ((r = pb - pa) > es) {
179	void _l = a, _r = ((unsigned char*)a)+r-1;
180	if (!((lrange < _l && rrange < _l) \|\|
181	(lrange > _r && rrange > _r)))
182	_pqsort(a, r / es, es, cmp, lrange, rrange);
183	}
184	if ((r = pd - pc) > es) {
185	void _l, _r;
186
187	/* Iterate rather than recurse to save stack space */
188	a = pn - r;
189	n = r / es;
190
191	_l = a;
192	_r = ((unsigned char*)a)+r-1;
193	if (!((lrange < _l && rrange < _l) \|\|
194	(lrange > _r && rrange > _r)))
195	goto loop;
196	}
197	/* qsort(pn - r, r / es, es, cmp);*/
198	}
199
200	void
201	pqsort(void *a, size_t n, size_t es,
202	int (cmp) __P((const void , const void *)), size_t lrange, size_t rrange)
203	{
204	_pqsort(a,n,es,cmp,((unsigned char)a)+(lrangees),
205	((unsigned char)a)+((rrange+1)es)-1);
206	}