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/*-
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 * Copyright (c) 1992, 1993
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 *        The Regents of the University of California.  All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 * 3. Neither the name of the University nor the names of its contributors
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 *    may be used to endorse or promote products derived from this software
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 *    without specific prior written permission.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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 * SUCH DAMAGE.
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 */
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#include <sys/cdefs.h>
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#include <sys/types.h>
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#include <assert.h>
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#include <errno.h>
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#include <stdlib.h>
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static __inline char        *med3(char *, char *, char *,
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    int (*)(const void *, const void *));
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static __inline void         swapfunc(char *, char *, size_t, int);
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#define min(a, b)        (a) < (b) ? a : b
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/*
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 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
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 */
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#define swapcode(TYPE, parmi, parmj, n) {                 \
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        size_t i = (n) / sizeof (TYPE);                 \
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        TYPE *pi = (TYPE *)(void *)(parmi);                 \
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        TYPE *pj = (TYPE *)(void *)(parmj);                 \
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        do {                                                 \
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                TYPE        t = *pi;                        \
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                *pi++ = *pj;                                \
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                *pj++ = t;                                \
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        } while (--i > 0);                                \
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}
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#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
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        es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
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static __inline void
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swapfunc(a, b, n, swaptype)
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        char *a, *b;
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        size_t n;
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        int swaptype;
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{
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        if (swaptype <= 1)
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                swapcode(long, a, b, n)
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        else
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                swapcode(char, a, b, n)
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}
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#define swap(a, b)                                                \
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        if (swaptype == 0) {                                        \
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                long t = *(long *)(void *)(a);                        \
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                *(long *)(void *)(a) = *(long *)(void *)(b);        \
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                *(long *)(void *)(b) = t;                        \
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        } else                                                        \
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                swapfunc(a, b, es, swaptype)
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#define vecswap(a, b, n) if ((n) > 0) swapfunc((a), (b), (size_t)(n), swaptype)
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static __inline char *
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med3(a, b, c, cmp)
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        char *a, *b, *c;
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        int (*cmp)(const void *, const void *);
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{
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        return cmp(a, b) < 0 ?
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               (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
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              :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
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}
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void
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qsort(a, n, es, cmp)
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        void *a;
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        size_t n, es;
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        int (*cmp)(const void *, const void *);
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{
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        char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
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        int d, r, swaptype, swap_cnt;
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loop:        SWAPINIT(a, es);
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        swap_cnt = 0;
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        if (n < 7) {
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                for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
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                        for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
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                             pl -= es)
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                                swap(pl, pl - es);
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                return;
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        }
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        pm = (char *) a + (n / 2) * es;
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        if (n > 7) {
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                pl = (char *) a;
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                pn = (char *) a + (n - 1) * es;
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                if (n > 40) {
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                        d = (n / 8) * es;
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                        pl = med3(pl, pl + d, pl + 2 * d, cmp);
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                        pm = med3(pm - d, pm, pm + d, cmp);
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                        pn = med3(pn - 2 * d, pn - d, pn, cmp);
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                }
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                pm = med3(pl, pm, pn, cmp);
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        }
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        swap(a, pm);
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        pa = pb = (char *) a + es;
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        pc = pd = (char *) a + (n - 1) * es;
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        for (;;) {
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                while (pb <= pc && (r = cmp(pb, a)) <= 0) {
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                        if (r == 0) {
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                                swap_cnt = 1;
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                                swap(pa, pb);
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                                pa += es;
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                        }
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                        pb += es;
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                }
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                while (pb <= pc && (r = cmp(pc, a)) >= 0) {
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                        if (r == 0) {
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                                swap_cnt = 1;
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                                swap(pc, pd);
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                                pd -= es;
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                        }
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                        pc -= es;
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                }
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                if (pb > pc)
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                        break;
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                swap(pb, pc);
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                swap_cnt = 1;
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                pb += es;
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                pc -= es;
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        }
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        if (swap_cnt == 0) {  /* Switch to insertion sort */
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                for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
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                        for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
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                             pl -= es)
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                                swap(pl, pl - es);
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                return;
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        }
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        pn = (char *) a + n * es;
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        r = min(pa - (char *) a, pb - pa);
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        vecswap(a, pb - r, r);
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        r = min(pd - pc, pn - pd - es);
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        vecswap(pb, pn - r, r);
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        if ((r = pb - pa) > es)
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                qsort(a, r / es, es, cmp);
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        if ((r = pd - pc) > es) {
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                /* Iterate rather than recurse to save stack space */
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                a = pn - r;
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                n = r / es;
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                goto loop;
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        }
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/*                qsort(pn - r, r / es, es, cmp);*/
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}