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发表于 2010-6-20 22:28:16
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1# VBProFan
FreeBSD 版本
- /*-
- * 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.
- *
- * $FreeBSD: src/sys/libkern/qsort.c,v 1.10 1999/08/28 00:46:35 peter Exp $
- */
- #include <sys/libkern.h>
- typedef int cmp_t __P((const void *, const void *));
- static __inline char *med3 __P((char *, char *, char *, cmp_t *));
- 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;
- cmp_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 ));
- }
- void
- qsort(a, n, es, cmp)
- void *a;
- size_t n, es;
- cmp_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 = 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);*/
- }
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