Skip to content

HTTPS clone URL

Subversion checkout URL

You can clone with HTTPS or Subversion.

Download ZIP
Fetching contributors…

Cannot retrieve contributors at this time

198 lines (175 sloc) 5.875 kb
/* 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);
}
Jump to Line
Something went wrong with that request. Please try again.