Adding upstream version 13.4.upstream/13.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 235 insertions, 0 deletions

diff --git a/src/port/qsort.c b/src/port/qsort.c
new file mode 100644
index 0000000..fa992e2
--- /dev/null
+++ b/src/port/qsort.c
@@ -0,0 +1,235 @@
+/*
+ *	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;
+		}
+	}
+}
+
+/*
+ * qsort comparator wrapper for strcmp.
+ */
+int
+pg_qsort_strcmp(const void *a, const void *b)
+{
+	return strcmp(*(const char *const *) a, *(const char *const *) b);
+}