Add freebsd's qsort

3 files changed, 168 insertions, 0 deletions

diff --git a/freebsd_qsort.c b/freebsd_qsort.c
new file mode 100644
index 0000000..cb3585d
--- /dev/null
+++ b/freebsd_qsort.c
@@ -0,0 +1,166 @@
+/*-
+ * 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 <stdlib.h>
+
+#include "sorters.h"
+
+static inline char	*med3(char *, char *, char *, cmpfun);
+static inline void	 swapfunc(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); 			\
+	TYPE *pi = (TYPE *) (parmi); 		\
+	TYPE *pj = (TYPE *) (parmj); 		\
+	do { 						\
+		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(char *a, char *b, char *c, cmpfun 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
+freebsd_qsort(void *a, size_t n, size_t es, cmpfun cmp)
+{
+	char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
+	size_t d, r;
+	int cmp_result;
+	int swaptype, swap_cnt;
+
+loop:	SWAPINIT(a, es);
+	swap_cnt = 0;
+	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;
+	}
+	pm = (char *)a + (n / 2) * es;
+	if (n > 7) {
+		pl = a;
+		pn = (char *)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 = (char *)a + es;
+
+	pc = pd = (char *)a + (n - 1) * es;
+	for (;;) {
+		while (pb <= pc && (cmp_result = cmp(pb, a)) <= 0) {
+			if (cmp_result == 0) {
+				swap_cnt = 1;
+				swap(pa, pb);
+				pa += es;
+			}
+			pb += es;
+		}
+		while (pb <= pc && (cmp_result = cmp(pc, a)) >= 0) {
+			if (cmp_result == 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 = (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;
+	}
+
+	pn = (char *)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);*/
+}
diff --git a/sorters.c b/sorters.c
index 5150272..33f85c2 100644
--- a/sorters.c
+++ b/sorters.c
@@ -1,6 +1,7 @@
 #include "sorters.h"
 
 const struct sorter sorters[] = {
+	{ .name = "freebsd",         .func = freebsd_qsort   },
 	{ .name = "glibc quicksort", .func = glibc_quicksort },
 	{ .name = "glibc mergesort", .func = glibc_mergesort },
 	{ .name = "musl",            .func = musl_qsort      },
diff --git a/sorters.h b/sorters.h
index c6850d2..2e1c4ec 100644
--- a/sorters.h
+++ b/sorters.h
@@ -6,6 +6,7 @@ typedef void (*sorter)(void *, size_t, size_t, cmpfun);
 void musl_qsort(void *, size_t, size_t, cmpfun);
 void glibc_quicksort(void *, size_t, size_t, cmpfun);
 void glibc_mergesort(void *, size_t, size_t, cmpfun);
+void freebsd_qsort(void *, size_t, size_t, cmpfun);
 
 extern const struct sorter {
 	const char *name;