[redis.git] / src / pqsort.c

/* The following is the NetBSD libc qsort implementation modified in order to
 * support partial sorting of ranges for Redis.
 *
 * Copyright(C) 2009-2010 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/types.h>

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

static inline char	*med3 (char *, char *, char *,
    int (*)(const void *, const void *));
static inline void	 swapfunc (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) (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) (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) (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	*
12d090d2	4	* Copyright(C) 2009-2010 Salvatore Sanfilippo. All rights reserved.
75fd597d	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
75fd597d	40	#include <sys/types.h>
	41
	42	#include <assert.h>
	43	#include <errno.h>
	44	#include <stdlib.h>
	45
d90b352d	46	static inline char med3 (char , char , char ,
	47	int ()(const void , const void *));
	48	static inline void swapfunc (char , char , size_t, int);
75fd597d	49
	50	#define min(a, b) (a) < (b) ? a : b
	51
	52	/*
	53	* Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
	54	*/
	55	#define swapcode(TYPE, parmi, parmj, n) { \
	56	size_t i = (n) / sizeof (TYPE); \
	57	TYPE pi = (TYPE )(void *)(parmi); \
	58	TYPE pj = (TYPE )(void *)(parmj); \
	59	do { \
	60	TYPE t = *pi; \
	61	pi++ = pj; \
	62	*pj++ = t; \
	63	} while (--i > 0); \
	64	}
	65
	66	#define SWAPINIT(a, es) swaptype = ((char )a - (char )0) % sizeof(long) \|\| \
	67	es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
	68
	69	static inline void
	70	swapfunc(char a, char b, size_t n, int swaptype)
	71	{
	72
	73	if (swaptype <= 1)
	74	swapcode(long, a, b, n)
	75	else
	76	swapcode(char, a, b, n)
	77	}
	78
	79	#define swap(a, b) \
	80	if (swaptype == 0) { \
	81	long t = (long )(void *)(a); \
	82	(long )(void )(a) = (long )(void )(b); \
	83	(long )(void *)(b) = t; \
	84	} else \
	85	swapfunc(a, b, es, swaptype)
	86
	87	#define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype)
	88
	89	static inline char *
	90	med3(char a, char b, char *c,
d90b352d	91	int (cmp) (const void , const void *))
75fd597d	92	{
	93
	94	return cmp(a, b) < 0 ?
	95	(cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
	96	:(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
	97	}
	98
	99	static void
	100	_pqsort(void *a, size_t n, size_t es,
d90b352d	101	int (cmp) (const void , const void ), void lrange, void *rrange)
75fd597d	102	{
	103	char pa, pb, pc, pd, pl, pm, *pn;
	104	size_t d, r;
	105	int swaptype, swap_cnt, cmp_result;
	106
	107	loop: SWAPINIT(a, es);
	108	swap_cnt = 0;
	109	if (n < 7) {
	110	for (pm = (char ) a + es; pm < (char ) a + n * es; pm += es)
	111	for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
	112	pl -= es)
	113	swap(pl, pl - es);
	114	return;
	115	}
	116	pm = (char ) a + (n / 2) es;
	117	if (n > 7) {
	118	pl = (char *) a;
	119	pn = (char ) a + (n - 1) es;
	120	if (n > 40) {
	121	d = (n / 8) * es;
	122	pl = med3(pl, pl + d, pl + 2 * d, cmp);
	123	pm = med3(pm - d, pm, pm + d, cmp);
	124	pn = med3(pn - 2 * d, pn - d, pn, cmp);
	125	}
	126	pm = med3(pl, pm, pn, cmp);
	127	}
	128	swap(a, pm);
	129	pa = pb = (char *) a + es;
	130
	131	pc = pd = (char ) a + (n - 1) es;
	132	for (;;) {
	133	while (pb <= pc && (cmp_result = cmp(pb, a)) <= 0) {
	134	if (cmp_result == 0) {
	135	swap_cnt = 1;
	136	swap(pa, pb);
	137	pa += es;
	138	}
	139	pb += es;
	140	}
	141	while (pb <= pc && (cmp_result = cmp(pc, a)) >= 0) {
	142	if (cmp_result == 0) {
	143	swap_cnt = 1;
	144	swap(pc, pd);
	145	pd -= es;
	146	}
	147	pc -= es;
	148	}
	149	if (pb > pc)
	150	break;
	151	swap(pb, pc);
	152	swap_cnt = 1;
	153	pb += es;
	154	pc -= es;
	155	}
	156	if (swap_cnt == 0) { /* Switch to insertion sort */
	157	for (pm = (char ) a + es; pm < (char ) a + n * es; pm += es)
	158	for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
	159	pl -= es)
	160	swap(pl, pl - es);
	161	return;
	162	}
	163
	164	pn = (char ) a + n es;
	165	r = min(pa - (char *) a, pb - pa);
166	vecswap(a, pb - r, r);
167	r = min((size_t)(pd - pc), pn - pd - es);
168	vecswap(pb, pn - r, r);
169	if ((r = pb - pa) > es) {
170	void _l = a, _r = ((unsigned char*)a)+r-1;
171	if (!((lrange < _l && rrange < _l) \|\|
172	(lrange > _r && rrange > _r)))
173	_pqsort(a, r / es, es, cmp, lrange, rrange);
174	}
175	if ((r = pd - pc) > es) {
176	void _l, _r;
177
178	/* Iterate rather than recurse to save stack space */
179	a = pn - r;
180	n = r / es;
181
182	_l = a;
183	_r = ((unsigned char*)a)+r-1;
184	if (!((lrange < _l && rrange < _l) \|\|
185	(lrange > _r && rrange > _r)))
186	goto loop;
187	}
188	/* qsort(pn - r, r / es, es, cmp);*/
189	}
190
191	void
192	pqsort(void *a, size_t n, size_t es,
d90b352d	193	int (cmp) (const void , const void *), size_t lrange, size_t rrange)
75fd597d	194	{
	195	_pqsort(a,n,es,cmp,((unsigned char)a)+(lrangees),
	196	((unsigned char)a)+((rrange+1)es)-1);
	197	}