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psort.c/h added. This is a partial qsort implementation that Redis wi…
…ll use when SORT+LIMIT is requested
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/* 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. */ | ||
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/* $NetBSD: qsort.c,v 1.19 2009/01/30 23:38:44 lukem Exp $ */ | ||
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/*- | ||
* 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. | ||
*/ | ||
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#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 */ | ||
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#include <sys/types.h> | ||
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#include <assert.h> | ||
#include <errno.h> | ||
#include <stdlib.h> | ||
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static inline char *med3 __P((char *, char *, char *, | ||
int (*)(const void *, const void *))); | ||
static inline void swapfunc __P((char *, char *, size_t, int)); | ||
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#define min(a, b) (a) < (b) ? a : b | ||
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/* | ||
* 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); \ | ||
} | ||
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#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \ | ||
es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1; | ||
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static inline void | ||
swapfunc(char *a, char *b, size_t n, int swaptype) | ||
{ | ||
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if (swaptype <= 1) | ||
swapcode(long, a, b, n) | ||
else | ||
swapcode(char, a, b, n) | ||
} | ||
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#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) | ||
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#define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype) | ||
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static inline char * | ||
med3(char *a, char *b, char *c, | ||
int (*cmp) __P((const void *, const void *))) | ||
{ | ||
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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 )); | ||
} | ||
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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; | ||
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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; | ||
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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; | ||
} | ||
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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; | ||
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/* Iterate rather than recurse to save stack space */ | ||
a = pn - r; | ||
n = r / es; | ||
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_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);*/ | ||
} | ||
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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); | ||
} |
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Original file line number | Diff line number | Diff line change |
---|---|---|
@@ -0,0 +1,15 @@ | ||
/* 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. | ||
* | ||
* See the pqsort.c file for the original copyright notice. */ | ||
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#ifndef __PQSORT_H | ||
#define __PQSORT_H | ||
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void | ||
pqsort(void *a, size_t n, size_t es, | ||
int (*cmp) __P((const void *, const void *)), size_t lrange, size_t rrange) | ||
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#endif |