--- /dev/null
+/* $Id: qsort.c,v 1.1 2000/03/18 15:12:19 ea Exp $
+ *
+ * FILE: ntoskrnl/rtl/qsort.c
+ * NOTE: Adapted from CygWin newlib 2000-03-12.
+ */
+/*
+FUNCTION
+<<qsort>>---sort an array
+
+INDEX
+ qsort
+
+ANSI_SYNOPSIS
+ #include <stdlib.h>
+ void qsort(void *<[base]>, size_t <[nmemb]>, size_t <[size]>,
+ int (*<[compar]>)(const void *, const void *) );
+
+TRAD_SYNOPSIS
+ #include <stdlib.h>
+ qsort(<[base]>, <[nmemb]>, <[size]>, <[compar]> )
+ char *<[base]>;
+ size_t <[nmemb]>;
+ size_t <[size]>;
+ int (*<[compar]>)();
+
+DESCRIPTION
+<<qsort>> sorts an array (beginning at <[base]>) of <[nmemb]> objects.
+<[size]> describes the size of each element of the array.
+
+You must supply a pointer to a comparison function, using the argument
+shown as <[compar]>. (This permits sorting objects of unknown
+properties.) Define the comparison function to accept two arguments,
+each a pointer to an element of the array starting at <[base]>. The
+result of <<(*<[compar]>)>> must be negative if the first argument is
+less than the second, zero if the two arguments match, and positive if
+the first argument is greater than the second (where ``less than'' and
+``greater than'' refer to whatever arbitrary ordering is appropriate).
+
+The array is sorted in place; that is, when <<qsort>> returns, the
+array elements beginning at <[base]> have been reordered.
+
+RETURNS
+<<qsort>> does not return a result.
+
+PORTABILITY
+<<qsort>> is required by ANSI (without specifying the sorting algorithm).
+*/
+
+/*-
+ * 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.
+ */
+
+#ifndef __GNUC__
+#define inline
+#endif
+
+/* FIXME: these types should be from the default includes */
+
+typedef int (* _pfunccmp_t) (char *, char *);
+typedef int size_t;
+
+#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 (
+ char * a,
+ char * b,
+ int 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 *)(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,
+ _pfunccmp_t 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 ));
+}
+
+
+/* EXPORTED */
+void
+qsort (
+ void * a,
+ size_t n,
+ size_t es,
+ _pfunccmp_t 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 = (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 = (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);
+ }
+ 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_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 = (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);*/
+}
+
+
+/* EOF */
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