X-Git-Url: http://www.aleph1.co.uk/gitweb/?p=yaffs2.git;a=blobdiff_plain;f=direct%2Fyaffs_qsort.c;fp=direct%2Fyaffs_qsort.c;h=187519fbdb55c824184d4be0a30fd53444562def;hp=0000000000000000000000000000000000000000;hb=f330fefa27f2c87f7dff414fe6227261327663b7;hpb=3d61aa9e6a51f89c067558dee27b02be4f564606

diff --git a/direct/yaffs_qsort.c b/direct/yaffs_qsort.c
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+++ b/direct/yaffs_qsort.c
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+/*
+ * 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 "yportenv.h"
+/* #include <linux/string.h> */
+
+/*
+ * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
+ */
+#define swapcode(TYPE, parmi, parmj, n) do { 		\
+	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);				\
+} while (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(char *a, char *b, int n, int swaptype)
+{
+	if (swaptype <= 1)
+		swapcode(long, a, b, n);
+	else
+		swapcode(char, a, b, n);
+}
+
+#define yswap(a, b) do {					\
+	if (swaptype == 0) {				\
+		long t = *(long *)(a);			\
+		*(long *)(a) = *(long *)(b);		\
+		*(long *)(b) = t;			\
+	} else						\
+		swapfunc(a, b, es, swaptype);		\
+} while (0)
+
+#define vecswap(a, b, n) 	if ((n) > 0) swapfunc(a, b, n, swaptype)
+
+static __inline 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));
+}
+
+#ifndef min
+#define min(a, b) (((a) < (b)) ? (a) : (b))
+#endif
+
+void
+yaffs_qsort(void *aa, size_t n, size_t es,
+	int (*cmp)(const void *, const void *))
+{
+	char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
+	int d, r, swaptype, swap_cnt;
+	register char *a = aa;
+
+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)
+				yswap(pl, pl - es);
+		return;
+	}
+	pm = (char *)a + (n / 2) * es;
+	if (n > 7) {
+		pl = (char *)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);
+	}
+	yswap(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_cnt = 1;
+				yswap(pa, pb);
+				pa += es;
+			}
+			pb += es;
+		}
+		while (pb <= pc && (r = cmp(pc, a)) >= 0) {
+			if (r == 0) {
+				swap_cnt = 1;
+				yswap(pc, pd);
+				pd -= es;
+			}
+			pc -= es;
+		}
+		if (pb > pc)
+			break;
+		yswap(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)
+				yswap(pl, pl - es);
+		return;
+	}
+
+	pn = (char *)a + n * es;
+	r = min(pa - (char *)a, pb - pa);
+	vecswap(a, pb - r, r);
+	r = min((long)(pd - pc), (long)(pn - pd - es));
+	vecswap(pb, pn - r, r);
+	r = pb - pa;
+	if (r > es)
+		yaffs_qsort(a, r / es, es, cmp);
+	r = pd - pc;
+	if (r > es) {
+		/* Iterate rather than recurse to save stack space */
+		a = pn - r;
+		n = r / es;
+		goto loop;
+	}
+/*		yaffs_qsort(pn - r, r / es, es, cmp);*/
+}