Use sort_template.h for qsort() and qsort_arg().
Reduce duplication by using the new template. Reviewed-by: Daniel Gustafsson <daniel@yesql.se> Discussion: https://postgr.es/m/CA%2BhUKGJ2-eaDqAum5bxhpMNhvuJmRDZxB_Tow0n-gse%2BHG0Yig%40mail.gmail.com
This commit is contained in:
Thomas Munro
parent
0a1f1d3cac
commit
f374f4d664
227
src/port/qsort.c
227
src/port/qsort.c
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@ -1,229 +1,16 @@
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/*
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* qsort.c: standard quicksort algorithm
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*
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* Modifications from vanilla NetBSD source:
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* Add do ... while() macro fix
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* Remove __inline, _DIAGASSERTs, __P
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* Remove ill-considered "swap_cnt" switch to insertion sort,
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* in favor of a simple check for presorted input.
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* Take care to recurse on the smaller partition, to bound stack usage.
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*
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* CAUTION: if you change this file, see also qsort_arg.c, gen_qsort_tuple.pl
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*
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* src/port/qsort.c
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*/
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/* $NetBSD: qsort.c,v 1.13 2003/08/07 16:43:42 agc Exp $ */
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/*-
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 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.
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||||
* 3. Neither the name of the University nor the names of its contributors
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||||
* may be used to endorse or promote products derived from this software
|
||||
* without specific prior written permission.
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||||
*
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||||
* 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
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||||
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
||||
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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||||
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "c.h"
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static char *med3(char *a, char *b, char *c,
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int (*cmp) (const void *, const void *));
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static void swapfunc(char *, char *, size_t, int);
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/*
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* Qsort routine based on J. L. Bentley and M. D. McIlroy,
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* "Engineering a sort function",
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* Software--Practice and Experience 23 (1993) 1249-1265.
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*
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* We have modified their original by adding a check for already-sorted input,
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* which seems to be a win per discussions on pgsql-hackers around 2006-03-21.
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*
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* Also, we recurse on the smaller partition and iterate on the larger one,
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* which ensures we cannot recurse more than log(N) levels (since the
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* partition recursed to is surely no more than half of the input). Bentley
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* and McIlroy explicitly rejected doing this on the grounds that it's "not
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* worth the effort", but we have seen crashes in the field due to stack
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* overrun, so that judgment seems wrong.
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*/
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#define swapcode(TYPE, parmi, parmj, n) \
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do { \
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size_t i = (n) / sizeof (TYPE); \
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TYPE *pi = (TYPE *)(void *)(parmi); \
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TYPE *pj = (TYPE *)(void *)(parmj); \
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do { \
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TYPE t = *pi; \
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*pi++ = *pj; \
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*pj++ = t; \
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} while (--i > 0); \
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} while (0)
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#define SWAPINIT(a, es) swaptype = ((char *)(a) - (char *)0) % sizeof(long) || \
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(es) % sizeof(long) ? 2 : (es) == sizeof(long)? 0 : 1
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static void
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swapfunc(char *a, char *b, size_t n, int swaptype)
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{
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if (swaptype <= 1)
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swapcode(long, a, b, n);
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else
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swapcode(char, a, b, n);
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}
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#define swap(a, b) \
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if (swaptype == 0) { \
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long t = *(long *)(void *)(a); \
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*(long *)(void *)(a) = *(long *)(void *)(b); \
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*(long *)(void *)(b) = t; \
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} else \
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swapfunc(a, b, es, swaptype)
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#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
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static char *
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med3(char *a, char *b, char *c, int (*cmp) (const void *, const void *))
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{
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return cmp(a, b) < 0 ?
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(cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a))
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: (cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c));
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}
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void
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pg_qsort(void *a, size_t n, size_t es, int (*cmp) (const void *, const void *))
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{
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char *pa,
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*pb,
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*pc,
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*pd,
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*pl,
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*pm,
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*pn;
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size_t d1,
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d2;
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int r,
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swaptype,
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presorted;
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loop:SWAPINIT(a, es);
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if (n < 7)
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{
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for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
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for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
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pl -= es)
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swap(pl, pl - es);
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return;
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}
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presorted = 1;
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for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
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{
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if (cmp(pm - es, pm) > 0)
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{
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presorted = 0;
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break;
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}
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}
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if (presorted)
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return;
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pm = (char *) a + (n / 2) * es;
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if (n > 7)
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{
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pl = (char *) a;
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pn = (char *) a + (n - 1) * es;
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if (n > 40)
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{
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size_t d = (n / 8) * es;
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pl = med3(pl, pl + d, pl + 2 * d, cmp);
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pm = med3(pm - d, pm, pm + d, cmp);
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pn = med3(pn - 2 * d, pn - d, pn, cmp);
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}
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pm = med3(pl, pm, pn, cmp);
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}
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swap(a, pm);
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pa = pb = (char *) a + es;
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pc = pd = (char *) a + (n - 1) * es;
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for (;;)
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{
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while (pb <= pc && (r = cmp(pb, a)) <= 0)
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{
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if (r == 0)
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{
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swap(pa, pb);
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pa += es;
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}
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pb += es;
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}
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while (pb <= pc && (r = cmp(pc, a)) >= 0)
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{
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if (r == 0)
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{
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swap(pc, pd);
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pd -= es;
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}
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pc -= es;
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}
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if (pb > pc)
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break;
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swap(pb, pc);
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pb += es;
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pc -= es;
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}
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pn = (char *) a + n * es;
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d1 = Min(pa - (char *) a, pb - pa);
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vecswap(a, pb - d1, d1);
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d1 = Min(pd - pc, pn - pd - es);
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vecswap(pb, pn - d1, d1);
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d1 = pb - pa;
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d2 = pd - pc;
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if (d1 <= d2)
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{
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/* Recurse on left partition, then iterate on right partition */
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if (d1 > es)
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pg_qsort(a, d1 / es, es, cmp);
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if (d2 > es)
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{
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/* Iterate rather than recurse to save stack space */
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/* pg_qsort(pn - d2, d2 / es, es, cmp); */
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a = pn - d2;
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n = d2 / es;
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goto loop;
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}
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}
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else
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{
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/* Recurse on right partition, then iterate on left partition */
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if (d2 > es)
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pg_qsort(pn - d2, d2 / es, es, cmp);
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if (d1 > es)
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{
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/* Iterate rather than recurse to save stack space */
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/* pg_qsort(a, d1 / es, es, cmp); */
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n = d1 / es;
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goto loop;
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}
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}
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}
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#define ST_SORT pg_qsort
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#define ST_ELEMENT_TYPE_VOID
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#define ST_COMPARE_RUNTIME_POINTER
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#define ST_SCOPE
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#define ST_DECLARE
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#define ST_DEFINE
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#include "lib/sort_template.h"
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/*
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* qsort comparator wrapper for strcmp.
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@ -1,226 +1,14 @@
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/*
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* qsort_arg.c: qsort with a passthrough "void *" argument
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*
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* Modifications from vanilla NetBSD source:
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* Add do ... while() macro fix
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* Remove __inline, _DIAGASSERTs, __P
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* Remove ill-considered "swap_cnt" switch to insertion sort,
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* in favor of a simple check for presorted input.
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* Take care to recurse on the smaller partition, to bound stack usage.
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*
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* CAUTION: if you change this file, see also qsort.c, gen_qsort_tuple.pl
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*
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* src/port/qsort_arg.c
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*/
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/* $NetBSD: qsort.c,v 1.13 2003/08/07 16:43:42 agc Exp $ */
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/*-
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* Copyright (c) 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* 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
|
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* SUCH DAMAGE.
|
||||
*/
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#include "c.h"
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static char *med3(char *a, char *b, char *c,
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qsort_arg_comparator cmp, void *arg);
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static void swapfunc(char *, char *, size_t, int);
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/*
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* Qsort routine based on J. L. Bentley and M. D. McIlroy,
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* "Engineering a sort function",
|
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* Software--Practice and Experience 23 (1993) 1249-1265.
|
||||
*
|
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* We have modified their original by adding a check for already-sorted input,
|
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* which seems to be a win per discussions on pgsql-hackers around 2006-03-21.
|
||||
*
|
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* Also, we recurse on the smaller partition and iterate on the larger one,
|
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* which ensures we cannot recurse more than log(N) levels (since the
|
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* partition recursed to is surely no more than half of the input). Bentley
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* and McIlroy explicitly rejected doing this on the grounds that it's "not
|
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* worth the effort", but we have seen crashes in the field due to stack
|
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* overrun, so that judgment seems wrong.
|
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*/
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#define swapcode(TYPE, parmi, parmj, n) \
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do { \
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size_t i = (n) / sizeof (TYPE); \
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TYPE *pi = (TYPE *)(void *)(parmi); \
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TYPE *pj = (TYPE *)(void *)(parmj); \
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do { \
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TYPE t = *pi; \
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*pi++ = *pj; \
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*pj++ = t; \
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} while (--i > 0); \
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} while (0)
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#define SWAPINIT(a, es) swaptype = ((char *)(a) - (char *)0) % sizeof(long) || \
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(es) % sizeof(long) ? 2 : (es) == sizeof(long)? 0 : 1
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static void
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swapfunc(char *a, char *b, size_t n, int swaptype)
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{
|
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if (swaptype <= 1)
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swapcode(long, a, b, n);
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else
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swapcode(char, a, b, n);
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}
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#define swap(a, b) \
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if (swaptype == 0) { \
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long t = *(long *)(void *)(a); \
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*(long *)(void *)(a) = *(long *)(void *)(b); \
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*(long *)(void *)(b) = t; \
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} else \
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swapfunc(a, b, es, swaptype)
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#define vecswap(a, b, n) if ((n) > 0) swapfunc(a, b, n, swaptype)
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static char *
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med3(char *a, char *b, char *c, qsort_arg_comparator cmp, void *arg)
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{
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return cmp(a, b, arg) < 0 ?
|
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(cmp(b, c, arg) < 0 ? b : (cmp(a, c, arg) < 0 ? c : a))
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: (cmp(b, c, arg) > 0 ? b : (cmp(a, c, arg) < 0 ? a : c));
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}
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void
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qsort_arg(void *a, size_t n, size_t es, qsort_arg_comparator cmp, void *arg)
|
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{
|
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char *pa,
|
||||
*pb,
|
||||
*pc,
|
||||
*pd,
|
||||
*pl,
|
||||
*pm,
|
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*pn;
|
||||
size_t d1,
|
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d2;
|
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int r,
|
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swaptype,
|
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presorted;
|
||||
|
||||
loop:SWAPINIT(a, es);
|
||||
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, arg) > 0;
|
||||
pl -= es)
|
||||
swap(pl, pl - es);
|
||||
return;
|
||||
}
|
||||
presorted = 1;
|
||||
for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
|
||||
{
|
||||
if (cmp(pm - es, pm, arg) > 0)
|
||||
{
|
||||
presorted = 0;
|
||||
break;
|
||||
}
|
||||
}
|
||||
if (presorted)
|
||||
return;
|
||||
pm = (char *) a + (n / 2) * es;
|
||||
if (n > 7)
|
||||
{
|
||||
pl = (char *) a;
|
||||
pn = (char *) a + (n - 1) * es;
|
||||
if (n > 40)
|
||||
{
|
||||
size_t d = (n / 8) * es;
|
||||
|
||||
pl = med3(pl, pl + d, pl + 2 * d, cmp, arg);
|
||||
pm = med3(pm - d, pm, pm + d, cmp, arg);
|
||||
pn = med3(pn - 2 * d, pn - d, pn, cmp, arg);
|
||||
}
|
||||
pm = med3(pl, pm, pn, cmp, arg);
|
||||
}
|
||||
swap(a, pm);
|
||||
pa = pb = (char *) a + es;
|
||||
pc = pd = (char *) a + (n - 1) * es;
|
||||
for (;;)
|
||||
{
|
||||
while (pb <= pc && (r = cmp(pb, a, arg)) <= 0)
|
||||
{
|
||||
if (r == 0)
|
||||
{
|
||||
swap(pa, pb);
|
||||
pa += es;
|
||||
}
|
||||
pb += es;
|
||||
}
|
||||
while (pb <= pc && (r = cmp(pc, a, arg)) >= 0)
|
||||
{
|
||||
if (r == 0)
|
||||
{
|
||||
swap(pc, pd);
|
||||
pd -= es;
|
||||
}
|
||||
pc -= es;
|
||||
}
|
||||
if (pb > pc)
|
||||
break;
|
||||
swap(pb, pc);
|
||||
pb += es;
|
||||
pc -= es;
|
||||
}
|
||||
pn = (char *) a + n * es;
|
||||
d1 = Min(pa - (char *) a, pb - pa);
|
||||
vecswap(a, pb - d1, d1);
|
||||
d1 = Min(pd - pc, pn - pd - es);
|
||||
vecswap(pb, pn - d1, d1);
|
||||
d1 = pb - pa;
|
||||
d2 = pd - pc;
|
||||
if (d1 <= d2)
|
||||
{
|
||||
/* Recurse on left partition, then iterate on right partition */
|
||||
if (d1 > es)
|
||||
qsort_arg(a, d1 / es, es, cmp, arg);
|
||||
if (d2 > es)
|
||||
{
|
||||
/* Iterate rather than recurse to save stack space */
|
||||
/* qsort_arg(pn - d2, d2 / es, es, cmp, arg); */
|
||||
a = pn - d2;
|
||||
n = d2 / es;
|
||||
goto loop;
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
/* Recurse on right partition, then iterate on left partition */
|
||||
if (d2 > es)
|
||||
qsort_arg(pn - d2, d2 / es, es, cmp, arg);
|
||||
if (d1 > es)
|
||||
{
|
||||
/* Iterate rather than recurse to save stack space */
|
||||
/* qsort_arg(a, d1 / es, es, cmp, arg); */
|
||||
n = d1 / es;
|
||||
goto loop;
|
||||
}
|
||||
}
|
||||
}
|
||||
#define ST_SORT qsort_arg
|
||||
#define ST_ELEMENT_TYPE_VOID
|
||||
#define ST_COMPARATOR_TYPE_NAME qsort_arg_comparator
|
||||
#define ST_COMPARE_RUNTIME_POINTER
|
||||
#define ST_COMPARE_ARG_TYPE void
|
||||
#define ST_SCOPE
|
||||
#define ST_DEFINE
|
||||
#include "lib/sort_template.h"
|
||||
|
|
|
|||
Loading…
Reference in New Issue