Add qsort() to libkern, taken from libc.

2 files changed, 175 insertions, 1 deletions

diff --git a/sys/libkern/Makefile b/sys/libkern/Makefile
index 220a179..2297c08 100644
--- a/sys/libkern/Makefile
+++ b/sys/libkern/Makefile
@@ -1,5 +1,5 @@
 #	@(#)Makefile	7.9 (Berkeley) 6/1/93
-# $Id: Makefile,v 1.9 1995/03/23 07:02:14 rgrimes Exp $
+# $Id: Makefile,v 1.10 1995/10/05 14:46:07 phk Exp $
 
 .undef NOPROFILE
 
@@ -8,6 +8,7 @@ CFLAGS+= -I${.CURDIR} -I${.CURDIR}/.. -DKERNEL
 
 # Stuff we call from the kernel
 SRCS+=	mcount.c
+SRCS+=  qsort.c
 SRCS+=	strcpy.c strcmp.c strncpy.c strncmp.c strcat.c
 SRCS+=	skpc.c scanc.c random.c inet_ntoa.c
 
diff --git a/sys/libkern/qsort.c b/sys/libkern/qsort.c
new file mode 100644
index 0000000..72ef243
--- /dev/null
+++ b/sys/libkern/qsort.c
@@ -0,0 +1,173 @@
+/*-
+ * 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. All advertising materials mentioning features or use of this software
+ *    must display the following acknowledgement:
+ *	This product includes software developed by the University of
+ *	California, Berkeley and its contributors.
+ * 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 defined(LIBC_SCCS) && !defined(lint)
+static char sccsid[] = "@(#)qsort.c	8.1 (Berkeley) 6/4/93";
+#endif /* LIBC_SCCS and not lint */
+
+#include <sys/types.h>
+
+static inline char	*med3 __P((char *, char *, char *, int (*)()));
+static inline void	 swapfunc __P((char *, char *, int, int));
+
+#define min(a, b)	(a) < (b) ? a : b
+
+/*
+ * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
+ */
+#define swapcode(TYPE, parmi, parmj, n) { 		\
+	long i = (n) / sizeof (TYPE); 			\
+	register TYPE *pi = (TYPE *) (parmi); 		\
+	register TYPE *pj = (TYPE *) (parmj); 		\
+	do { 						\
+		register TYPE	t = *pi;		\
+		*pi++ = *pj;				\
+		*pj++ = t;				\
+        } while (--i > 0);				\
+}
+
+#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
+	es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
+
+static inline void
+swapfunc(a, b, n, swaptype)
+	char *a, *b;
+	int n, 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 *)(a);			\
+		*(long *)(a) = *(long *)(b);		\
+		*(long *)(b) = t;			\
+	} else						\
+		swapfunc(a, b, es, swaptype)
+
+#define vecswap(a, b, n) 	if ((n) > 0) swapfunc(a, b, n, swaptype)
+
+static inline char *
+med3(a, b, c, cmp)
+	char *a, *b, *c;
+	int (*cmp)();
+{
+	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
+qsort(a, n, es, cmp)
+	void *a;
+	size_t n, es;
+	int (*cmp)();
+{
+	char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
+	int d, r, swaptype, swap_cnt;
+
+loop:	SWAPINIT(a, es);
+	swap_cnt = 0;
+	if (n < 7) {
+		for (pm = 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 = a + (n / 2) * es;
+	if (n > 7) {
+		pl = a;
+		pn = 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 = a + es;
+
+	pc = pd = a + (n - 1) * es;
+	for (;;) {
+		while (pb <= pc && (r = cmp(pb, a)) <= 0) {
+			if (r == 0) {
+				swap_cnt = 1;
+				swap(pa, pb);
+				pa += es;
+			}
+			pb += es;
+		}
+		while (pb <= pc && (r = cmp(pc, a)) >= 0) {
+			if (r == 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 = 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;
+	}
+
+	pn = a + n * es;
+	r = min(pa - (char *)a, pb - pa);
+	vecswap(a, pb - r, r);
+	r = min(pd - pc, pn - pd - es);
+	vecswap(pb, pn - r, r);
+	if ((r = pb - pa) > es)
+		qsort(a, r / es, es, cmp);
+	if ((r = pd - pc) > es) {
+		/* Iterate rather than recurse to save stack space */
+		a = pn - r;
+		n = r / es;
+		goto loop;
+	}
+/*		qsort(pn - r, r / es, es, cmp);*/
+}