Re: qsort can get very slow

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why ever the attachment was missing from the last mail, here it is...

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diff -Nurp --exclude='.bzr*' tin-2.1.1/configure.in tin-2.1.1/configure.in
--- tin-2.1.1/configure.in	2012-01-01 02:58:15.040563751 +0100
+++ tin-2.1.1/configure.in	2012-02-18 16:33:26.979840653 +0100
@@ -1009,6 +1009,7 @@ AC_CHECK_FUNCS(\
 	getcwd \
 	gettimeofday \
 	getwd \
+	heapsort \
 	inet_aton \
 	is_xterm \
 	isascii \
@@ -1231,6 +1232,7 @@ CF_CHECK_DECL(\
 	getcwd \
 	getopt \
 	getwd \
+	heapsort \
 	ioctl \
 	isascii \
 	kill \
diff -Nurp --exclude='.bzr*' tin-2.1.1/include/autoconf.hin tin-2.1.1/include/autoconf.hin
--- tin-2.1.1/include/autoconf.hin	2011-12-24 16:17:44.000000000 +0100
+++ tin-2.1.1/include/autoconf.hin	2012-02-18 16:34:34.222055460 +0100
@@ -260,6 +260,7 @@
 #	undef HAVE_GETSERVBYNAME
 #	undef HAVE_GETTIMEOFDAY
 #	undef HAVE_GETWD
+#	undef HAVE_HEAPSORT
 #	undef HAVE_ICONV
 #	undef HAVE_INET_ADDR
 #	undef HAVE_INET_ATON
@@ -367,6 +368,7 @@
 #	undef DECL_GETHOSTNAME
 #	undef DECL_GETOPT
 #	undef DECL_GETWD
+#	undef DECL_HEAPSORT
 #	undef DECL_INET_ADDR
 #	undef DECL_INET_ATON
 #	undef DECL_INET_NTOA
diff -Nurp --exclude='.bzr*' tin-2.1.1/include/extern.h tin-2.1.1/include/extern.h
--- tin-2.1.1/include/extern.h	2011-12-24 16:17:25.000000000 +0100
+++ tin-2.1.1/include/extern.h	2012-02-18 16:36:22.114445742 +0100
@@ -156,6 +156,9 @@
 #ifdef DECL_GETWD
 	extern char *getwd(char *);
 #endif /* DECL_GETWD */
+#ifdef DECL_HEAPSORT
+	extern int heapsort(void *, size_t, size_t, int (*)(t_comptype*, t_comptype*));
+#endif /* DECL_HEAPSORT */
 #ifdef DECL_INET_ADDR
 	extern unsigned long inet_addr(const char *);
 #endif /* DECL_INET_ADDR */
diff -Nurp --exclude='.bzr*' tin-2.1.1/include/proto.h tin-2.1.1/include/proto.h
--- tin-2.1.1/include/proto.h	2011-12-24 16:17:25.000000000 +0100
+++ tin-2.1.1/include/proto.h	2012-02-18 16:37:03.272698318 +0100
@@ -242,6 +242,11 @@ extern const char *get_host_name(void);
 	extern char *build_sender(void);
 #endif /* !FORGERY */
 
+/* heapsort.c */
+#ifndef HAVE_HEAPSORT
+	extern int heapsort(void *, size_t, size_t, int (*)(const void *, const void *));
+#endif /* !HAVE_HEAPSORT */
+
 /* inews.c */
 extern t_bool submit_news_file(char *name, struct t_group *group, char *a_message_id);
 extern void get_from_name(char *from_name, struct t_group *thisgrp);
diff -Nurp --exclude='.bzr*' tin-2.1.1/include/tin.h tin-2.1.1/include/tin.h
--- tin-2.1.1/include/tin.h	2011-12-24 16:17:26.000000000 +0100
+++ tin-2.1.1/include/tin.h	2012-02-18 16:58:23.579313913 +0100
@@ -2002,6 +2002,9 @@ typedef int (*t_compfunc)(t_comptype, t_
 
 #define _CDECL
 
+/* set to (void)heapsort or qsort */
+#define tin_sort (void)heapsort
+
 /* Seperator between dir part of path & the filename */
 #define DIRSEP	'/'
 
diff -Nurp --exclude='.bzr*' tin-2.1.1/src/Makefile.in tin-2.1.1/src/Makefile.in
--- tin-2.1.1/src/Makefile.in	2011-12-24 16:19:35.000000000 +0100
+++ tin-2.1.1/src/Makefile.in	2012-02-18 01:56:55.469171566 +0100
@@ -153,6 +153,7 @@ CFILES	= \
 	$(SRCDIR)/group.c \
 	$(SRCDIR)/hashstr.c \
 	$(SRCDIR)/header.c \
+	$(SRCDIR)/heapsort.c \
 	$(SRCDIR)/help.c \
 	$(SRCDIR)/inews.c \
 	$(SRCDIR)/init.c \
@@ -229,6 +230,7 @@ OFILES	= @ALLOCA@ $(EXTRAOBJS) \
 	$(OBJDIR)/group$o \
 	$(OBJDIR)/hashstr$o \
 	$(OBJDIR)/header$o \
+	$(OBJDIR)/heapsort$o \
 	$(OBJDIR)/help$o \
 	$(OBJDIR)/inews$o \
 	$(OBJDIR)/init$o \
@@ -526,6 +528,7 @@ $(OBJDIR)/group$o :		$(SRCDIR)/group.c $
 $(OBJDIR)/hashstr$o :		$(SRCDIR)/hashstr.c $(TIN_DEP)
 $(OBJDIR)/header$o :		$(SRCDIR)/header.c $(TIN_DEP) \
 				$(INCDIR)/tnntp.h
+$(OBJDIR)/heapsort$o :		$(SRCDIR)/heapsort.c $(TIN_DEP)
 $(OBJDIR)/help$o :		$(SRCDIR)/help.c $(TIN_DEP) \
 				$(INCDIR)/keymap.h
 $(OBJDIR)/inews$o :		$(SRCDIR)/inews.c $(TIN_DEP) \
diff -Nurp --exclude='.bzr*' tin-2.1.1/src/art.c tin-2.1.1/src/art.c
--- tin-2.1.1/src/art.c	2011-12-24 16:19:18.000000000 +0100
+++ tin-2.1.1/src/art.c	2012-02-18 16:31:46.600592238 +0100
@@ -52,7 +52,7 @@
 /*
  * TODO: fixup to remove CURR_GROUP dependency in all sort funcs
  */
-#define SortBy(func)	qsort(arts, (size_t) top_art, sizeof(struct t_article), func);
+#define SortBy(func)	tin_sort(arts, (size_t) top_art, sizeof(struct t_article), func);
 
 int top_art = 0;				/* # of articles in arts[] */
 
@@ -161,7 +161,7 @@ find_base(
 
 
 /*
- * Longword comparison routine for the qsort()
+ * Longword comparison routine for the tin_sort()
  */
 static int
 base_comp(
@@ -362,7 +362,7 @@ setup_hard_base(
 				}
 			}
 			CLOSEDIR(d);
-			qsort((char *) base, (size_t) grpmenu.max, sizeof(t_artnum), base_comp);
+			tin_sort((char *) base, (size_t) grpmenu.max, sizeof(t_artnum), base_comp);
 		}
 	}
 
@@ -1304,15 +1304,15 @@ sort_base(
 	switch (sort_threads_type) {
 		case SORT_THREADS_BY_SCORE_DESCEND:
 		case SORT_THREADS_BY_SCORE_ASCEND:
-			qsort(base, (size_t) grpmenu.max, sizeof(t_artnum), score_comp_base);
+			tin_sort(base, (size_t) grpmenu.max, sizeof(t_artnum), score_comp_base);
 			break;
 
 		case SORT_THREADS_BY_LAST_POSTING_DATE_DESCEND:
-			qsort(base, (size_t) grpmenu.max, sizeof(t_artnum), last_date_comp_base_desc);
+			tin_sort(base, (size_t) grpmenu.max, sizeof(t_artnum), last_date_comp_base_desc);
 			break;
 
 		case SORT_THREADS_BY_LAST_POSTING_DATE_ASCEND:
-			qsort(base, (size_t) grpmenu.max, sizeof(t_artnum), last_date_comp_base_asc);
+			tin_sort(base, (size_t) grpmenu.max, sizeof(t_artnum), last_date_comp_base_asc);
 			break;
 	}
 }
diff -Nurp --exclude='.bzr*' tin-2.1.1/src/heapsort.c tin-2.1.1/src/heapsort.c
--- tin-2.1.1/src/heapsort.c	1970-01-01 01:00:00.000000000 +0100
+++ tin-2.1.1/src/heapsort.c	2012-02-19 12:57:51.507353218 +0100
@@ -0,0 +1,196 @@
+/*-
+ * Copyright (c) 1991, 1993
+ *	The Regents of the University of California.  All rights reserved.
+ *
+ * This code is derived from software contributed to Berkeley by
+ * Ronnie Kon at Mindcraft Inc., Kevin Lew and Elmer Yglesias.
+ *
+ * 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.
+ * 4. 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.
+ */
+
+#if 0
+#	include <sys/cdefs.h>
+#	include <errno.h>
+#	include <stddef.h>
+#	include <stdlib.h>
+#else
+#	ifndef TIN_H
+#       include "tin.h"
+#	else
+#	endif /* !TIN_H */
+#endif /* 0 */
+
+#ifndef HAVE_HEAPSORT
+/*
+ * Swap two areas of size number of bytes.  Although qsort(3) permits random
+ * blocks of memory to be sorted, sorting pointers is almost certainly the
+ * common case (and, were it not, could easily be made so).  Regardless, it
+ * isn't worth optimizing; the SWAP's get sped up by the cache, and pointer
+ * arithmetic gets lost in the time required for comparison function calls.
+ */
+#define	SWAP(a, b, count, size, tmp) { \
+	count = size; \
+	do { \
+		tmp = *a; \
+		*a++ = *b; \
+		*b++ = tmp; \
+	} while (--count); \
+}
+
+/* Copy one block of size size to another. */
+#define COPY(a, b, count, size, tmp1, tmp2) { \
+	count = size; \
+	tmp1 = a; \
+	tmp2 = b; \
+	do { \
+		*tmp1++ = *tmp2++; \
+	} while (--count); \
+}
+
+/*
+ * Build the list into a heap, where a heap is defined such that for
+ * the records K1 ... KN, Kj/2 >= Kj for 1 <= j/2 <= j <= N.
+ *
+ * There two cases.  If j == nmemb, select largest of Ki and Kj.  If
+ * j < nmemb, select largest of Ki, Kj and Kj+1.
+ */
+#define CREATE(initval, nmemb, par_i, child_i, par, child, size, count, tmp) { \
+	for (par_i = initval; (child_i = par_i * 2) <= nmemb; \
+	    par_i = child_i) { \
+		child = abase + child_i * size; \
+		if (child_i < nmemb && compar(child, child + size) < 0) { \
+			child += size; \
+			++child_i; \
+		} \
+		par = abase + par_i * size; \
+		if (compar(child, par) <= 0) \
+			break; \
+		SWAP(par, child, count, size, tmp); \
+	} \
+}
+
+/*
+ * Select the top of the heap and 'heapify'.  Since by far the most expensive
+ * action is the call to the compar function, a considerable optimization
+ * in the average case can be achieved due to the fact that k, the displaced
+ * elememt, is ususally quite small, so it would be preferable to first
+ * heapify, always maintaining the invariant that the larger child is copied
+ * over its parent's record.
+ *
+ * Then, starting from the *bottom* of the heap, finding k's correct place,
+ * again maintianing the invariant.  As a result of the invariant no element
+ * is 'lost' when k is assigned its correct place in the heap.
+ *
+ * The time savings from this optimization are on the order of 15-20% for the
+ * average case. See Knuth, Vol. 3, page 158, problem 18.
+ *
+ * XXX Don't break the #define SELECT line, below.  Reiser cpp gets upset.
+ */
+#define SELECT(par_i, child_i, nmemb, par, child, size, k, count, tmp1, tmp2) { \
+	for (par_i = 1; (child_i = par_i * 2) <= nmemb; par_i = child_i) { \
+		child = abase + child_i * size; \
+		if (child_i < nmemb && compar(child, child + size) < 0) { \
+			child += size; \
+			++child_i; \
+		} \
+		par = abase + par_i * size; \
+		COPY(par, child, count, size, tmp1, tmp2); \
+	} \
+	for (;;) { \
+		child_i = par_i; \
+		par_i = child_i / 2; \
+		child = abase + child_i * size; \
+		par = abase + par_i * size; \
+		if (child_i == 1 || compar(k, par) < 0) { \
+			COPY(child, k, count, size, tmp1, tmp2); \
+			break; \
+		} \
+		COPY(child, par, count, size, tmp1, tmp2); \
+	} \
+}
+
+/*
+ * Heapsort -- Knuth, Vol. 3, page 145.  Runs in O (N lg N), both average
+ * and worst.  While heapsort is faster than the worst case of quicksort,
+ * the BSD quicksort does median selection so that the chance of finding
+ * a data set that will trigger the worst case is nonexistent.  Heapsort's
+ * only advantage over quicksort is that it requires little additional memory.
+ */
+int
+heapsort(
+	void *vbase,
+	size_t nmemb,
+	size_t size,
+	int (*compar)(const void *, const void *))
+{
+	size_t cnt, i, j, l;
+	char tmp, *tmp1, *tmp2;
+	char *abase, *k, *p, *t;
+
+	if (nmemb <= 1)
+		return (0);
+
+	if (!size) {
+		errno = EINVAL;
+		return (-1);
+	}
+
+#if 0
+	if ((k = malloc(size)) == NULL)
+		return (-1);
+#else
+	k = my_malloc(size);
+#endif /* 0 */
+
+	/*
+	 * Items are numbered from 1 to nmemb, so offset from size bytes
+	 * below the starting address.
+	 */
+	abase = (char *)vbase - size;
+
+	for (l = nmemb / 2 + 1; --l;)
+		CREATE(l, nmemb, i, j, t, p, size, cnt, tmp);
+
+	/*
+	 * For each element of the heap, save the largest element into its
+	 * final slot, save the displaced element (k), then recreate the
+	 * heap.
+	 */
+	while (nmemb > 1) {
+		COPY(k, abase + nmemb * size, cnt, size, tmp1, tmp2);
+		COPY(abase + nmemb * size, abase + size, cnt, size, tmp1, tmp2);
+		--nmemb;
+		SELECT(i, j, nmemb, t, p, size, k, cnt, tmp1, tmp2);
+	}
+	free(k);
+	return (0);
+}
+#else
+static void has_heapsort(void);
+static void has_heapsort(		/* ANSI C requires non-empty source file */
+	void)
+{
+}
+#endif /* !HAVE_HEAPSORT */
diff -Nurp --exclude='.bzr*' tin-2.1.1/src/select.c tin-2.1.1/src/select.c
--- tin-2.1.1/src/select.c	2011-12-24 16:19:20.000000000 +0100
+++ tin-2.1.1/src/select.c	2012-02-18 16:37:55.892692182 +0100
@@ -813,7 +813,7 @@ yank_active_file(
 
 
 /*
- * Sort active[] and associated qsort() helper function
+ * Sort active[] and associated tin_sort() helper function
  */
 static int
 active_comp(
@@ -876,7 +876,7 @@ sort_active_file(
 {
 	save_restore_curr_group(TRUE);
 
-	qsort(active, (size_t) num_active, sizeof(struct t_group), active_comp);
+	tin_sort(active, (size_t) num_active, sizeof(struct t_group), active_comp);
 	group_rehash(yanked_out);
 
 	selmenu.curr = save_restore_curr_group(FALSE);

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