bsd/kern/qsort.c

   1 /*
   2  * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28 /*
  29  * Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved
  30  *
  31  * Copyright (c) 1992, 1993
  32  *      The Regents of the University of California.  All rights reserved.
  33  *
  34  * Redistribution and use in source and binary forms, with or without
  35  * modification, are permitted provided that the following conditions
  36  * are met:
  37  * 1. Redistributions of source code must retain the above copyright
  38  *    notice, this list of conditions and the following disclaimer.
  39  * 2. Redistributions in binary form must reproduce the above copyright
  40  *    notice, this list of conditions and the following disclaimer in the
  41  *    documentation and/or other materials provided with the distribution.
  42  * 3. All advertising materials mentioning features or use of this software
  43  *    must display the following acknowledgement:
  44  *      This product includes software developed by the University of
  45  *      California, Berkeley and its contributors.
  46  * 4. Neither the name of the University nor the names of its contributors
  47  *    may be used to endorse or promote products derived from this software
  48  *    without specific prior written permission.
  49  *
  50  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  51  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  52  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  53  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  54  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  55  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  56  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  57  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  58  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  59  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  60  * SUCH DAMAGE.
  61  *
  62  *      @(#)qsort.c     8.1 (Berkeley) 6/4/93
  63  */
  64
  65
  66 #include <sys/types.h>
  67 //#include <stdlib.h>
  68 #include <sys/kpi_private.h>
  69
  70 __private_extern__
  71 void
  72 qsort(void *a, size_t n, size_t es, int (*cmp)(const void *, const void *));
  73
  74 static inline char      *med3(char *, char *, char *, int (*)(const void *, const void *));
  75 static inline void       swapfunc(char *, char *, int, int);
  76
  77 #define min(a, b)       (a) < (b) ? a : b
  78
  79 /*
  80  * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
  81  */
  82 #define swapcode(TYPE, parmi, parmj, n) {               \
  83         long i = (n) / sizeof (TYPE);                   \
  84         TYPE *pi = (TYPE *) (parmi);                    \
  85         TYPE *pj = (TYPE *) (parmj);                    \
  86         do {                                            \
  87                 TYPE    t = *pi;                        \
  88                 *pi++ = *pj;                            \
  89                 *pj++ = t;                              \
  90         } while (--i > 0);                              \
  91 }
  92
  93 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
  94         es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
  95
  96 static inline void
  97 swapfunc(char *a, char *b, int n, int swaptype)
  98 {
  99         if(swaptype <= 1)
 100                 swapcode(long, a, b, n)
 101         else
 102                 swapcode(char, a, b, n)
 103 }
 104
 105 #define swap(a, b)                                      \
 106         if (swaptype == 0) {                            \
 107                 long t = *(long *)(a);                  \
 108                 *(long *)(a) = *(long *)(b);            \
 109                 *(long *)(b) = t;                       \
 110         } else                                          \
 111                 swapfunc(a, b, es, swaptype)
 112
 113 #define vecswap(a, b, n)        if ((n) > 0) swapfunc(a, b, n, swaptype)
 114
 115 static inline char *
 116 med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
 117 {
 118         return cmp(a, b) < 0 ?
 119                (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a ))
 120               :(cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c ));
 121 }
 122
 123 __private_extern__
 124 void
 125 qsort(void *a, size_t n, size_t es, int (*cmp)(const void *, const void *))
 126 {
 127         char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
 128         int d, swaptype, swap_cnt;
 129         int r;
 130
 131 loop:   SWAPINIT(a, es);
 132         swap_cnt = 0;
 133         if (n < 7) {
 134                 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
 135                         for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
 136                              pl -= es)
 137                                 swap(pl, pl - es);
 138                 return;
 139         }
 140         pm = (char *)a + (n / 2) * es;
 141         if (n > 7) {
 142                 pl = a;
 143                 pn = (char *)a + (n - 1) * es;
 144                 if (n > 40) {
 145                         d = (n / 8) * es;
 146                         pl = med3(pl, pl + d, pl + 2 * d, cmp);
 147                         pm = med3(pm - d, pm, pm + d, cmp);
 148                         pn = med3(pn - 2 * d, pn - d, pn, cmp);
 149                 }
 150                 pm = med3(pl, pm, pn, cmp);
 151         }
 152         swap(a, pm);
 153         pa = pb = (char *)a + es;
 154
 155         pc = pd = (char *)a + (n - 1) * es;
 156         for (;;) {
 157                 while (pb <= pc && (r = cmp(pb, a)) <= 0) {
 158                         if (r == 0) {
 159                                 swap_cnt = 1;
 160                                 swap(pa, pb);
 161                                 pa += es;
 162                         }
 163                         pb += es;
 164                 }
 165                 while (pb <= pc && (r = cmp(pc, a)) >= 0) {
 166                         if (r == 0) {
 167                                 swap_cnt = 1;
 168                                 swap(pc, pd);
 169                                 pd -= es;
 170                         }
 171                         pc -= es;
 172                 }
 173                 if (pb > pc)
 174                         break;
 175                 swap(pb, pc);
 176                 swap_cnt = 1;
 177                 pb += es;
 178                 pc -= es;
 179         }
 180         if (swap_cnt == 0) {  /* Switch to insertion sort */
 181                 for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
 182                         for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
 183                              pl -= es)
 184                                 swap(pl, pl - es);
 185                 return;
 186         }
 187
 188         pn = (char *)a + n * es;
 189         r = min(pa - (char *)a, pb - pa);
 190         vecswap(a, pb - r, r);
 191         r = min((size_t)(pd - pc), pn - pd - es);
 192         vecswap(pb, pn - r, r);
 193         if ((size_t)(r = pb - pa) > es)
 194                 qsort(a, r / es, es, cmp);
 195         if ((size_t)(r = pd - pc) > es) {
 196                 /* Iterate rather than recurse to save stack space */
 197                 a = pn - r;
 198                 n = r / es;
 199                 goto loop;
 200         }
 201 /*              qsort(pn - r, r / es, es, cmp);*/
 202 }
 203
 204 /* private KPI */
 205 void
 206 kx_qsort (void *array, size_t nm, size_t member_size, int (*cmpf)(const void *, const void *)) {
 207         qsort (array, nm, member_size, cmpf);
 208 }