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Postgres FD Implementation
Commit f374f4d6 authored by Thomas Munro's avatar Thomas Munro
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Use sort_template.h for qsort() and qsort_arg(). 

Reduce duplication by using the new template.
Reviewed-by: default avatarDaniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/CA%2BhUKGJ2-eaDqAum5bxhpMNhvuJmRDZxB_Tow0n-gse%2BHG0Yig%40mail.gmail.com
parent 0a1f1d3c
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src/port/qsort.c
View file @ f374f4d6
/*
* qsort.c: standard quicksort algorithm
*
* Modifications from vanilla NetBSD source:
* Add do ... while() macro fix
* Remove __inline, _DIAGASSERTs, __P
* Remove ill-considered "swap_cnt" switch to insertion sort,
* in favor of a simple check for presorted input.
* Take care to recurse on the smaller partition, to bound stack usage.
*
* CAUTION: if you change this file, see also qsort_arg.c, gen_qsort_tuple.pl
*
* src/port/qsort.c
*/
/* $NetBSD: qsort.c,v 1.13 2003/08/07 16:43:42 agc 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 "c.h"
static char *med3(char *a, char *b, char *c,
int (*cmp) (const void *, const void *));
static void swapfunc(char *, char *, size_t, int);
/*
* Qsort routine based on J. L. Bentley and M. D. McIlroy,
* "Engineering a sort function",
* Software--Practice and Experience 23 (1993) 1249-1265.
*
* We have modified their original by adding a check for already-sorted input,
* which seems to be a win per discussions on pgsql-hackers around 2006-03-21.
*
* Also, we recurse on the smaller partition and iterate on the larger one,
* which ensures we cannot recurse more than log(N) levels (since the
* partition recursed to is surely no more than half of the input). Bentley
* and McIlroy explicitly rejected doing this on the grounds that it's "not
* worth the effort", but we have seen crashes in the field due to stack
* overrun, so that judgment seems wrong.
*/
#define swapcode(TYPE, parmi, parmj, n) \
do { \
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); \
} while (0)
#define SWAPINIT(a, es) swaptype = ((char *)(a) - (char *)0) % sizeof(long) || \
(es) % sizeof(long) ? 2 : (es) == sizeof(long)? 0 : 1
static 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, n, swaptype)
static 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));
}
void
pg_qsort(void *a, size_t n, size_t es, int (*cmp) (const void *, const void *))
{
char *pa,
*pb,
*pc,
*pd,
*pl,
*pm,
*pn;
size_t d1,
d2;
int r,
swaptype,
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) > 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) > 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);
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 && (r = cmp(pb, a)) <= 0)
{
if (r == 0)
{
swap(pa, pb);
pa += es;
}
pb += es;
}
while (pb <= pc && (r = cmp(pc, a)) >= 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)
pg_qsort(a, d1 / es, es, cmp);
if (d2 > es)
{
/* Iterate rather than recurse to save stack space */
/* pg_qsort(pn - d2, d2 / es, es, cmp); */
a = pn - d2;
n = d2 / es;
goto loop;
}
}
else
{
/* Recurse on right partition, then iterate on left partition */
if (d2 > es)
pg_qsort(pn - d2, d2 / es, es, cmp);
if (d1 > es)
{
/* Iterate rather than recurse to save stack space */
/* pg_qsort(a, d1 / es, es, cmp); */
n = d1 / es;
goto loop;
}
}
}
#define ST_SORT pg_qsort
#define ST_ELEMENT_TYPE_VOID
#define ST_COMPARE_RUNTIME_POINTER
#define ST_SCOPE
#define ST_DECLARE
#define ST_DEFINE
#include "lib/sort_template.h"
/*
* qsort comparator wrapper for strcmp.
......
src/port/qsort_arg.c
View file @ f374f4d6
/*
* qsort_arg.c: qsort with a passthrough "void *" argument
*
* Modifications from vanilla NetBSD source:
* Add do ... while() macro fix
* Remove __inline, _DIAGASSERTs, __P
* Remove ill-considered "swap_cnt" switch to insertion sort,
* in favor of a simple check for presorted input.
* Take care to recurse on the smaller partition, to bound stack usage.
*
* CAUTION: if you change this file, see also qsort.c, gen_qsort_tuple.pl
*
* src/port/qsort_arg.c
*/
/* $NetBSD: qsort.c,v 1.13 2003/08/07 16:43:42 agc 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 "c.h"
static char *med3(char *a, char *b, char *c,
qsort_arg_comparator cmp, void *arg);
static void swapfunc(char *, char *, size_t, int);
/*
* Qsort routine based on J. L. Bentley and M. D. McIlroy,
* "Engineering a sort function",
* Software--Practice and Experience 23 (1993) 1249-1265.
*
* We have modified their original by adding a check for already-sorted input,
* which seems to be a win per discussions on pgsql-hackers around 2006-03-21.
*
* Also, we recurse on the smaller partition and iterate on the larger one,
* which ensures we cannot recurse more than log(N) levels (since the
* partition recursed to is surely no more than half of the input). Bentley
* and McIlroy explicitly rejected doing this on the grounds that it's "not
* worth the effort", but we have seen crashes in the field due to stack
* overrun, so that judgment seems wrong.
*/
#define swapcode(TYPE, parmi, parmj, n) \
do { \
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); \
} while (0)
#define SWAPINIT(a, es) swaptype = ((char *)(a) - (char *)0) % sizeof(long) || \
(es) % sizeof(long) ? 2 : (es) == sizeof(long)? 0 : 1
static 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, n, swaptype)
static char *
med3(char *a, char *b, char *c, qsort_arg_comparator cmp, void *arg)
{
return cmp(a, b, arg) < 0 ?
(cmp(b, c, arg) < 0 ? b : (cmp(a, c, arg) < 0 ? c : a))
: (cmp(b, c, arg) > 0 ? b : (cmp(a, c, arg) < 0 ? a : c));
}
void
qsort_arg(void *a, size_t n, size_t es, qsort_arg_comparator cmp, void *arg)
{
char *pa,
*pb,
*pc,
*pd,
*pl,
*pm,
*pn;
size_t d1,
d2;
int r,
swaptype,
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"
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