lib/roken/qsort.c

   1 /*-
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if 0
  31 #if defined(LIBC_SCCS) && !defined(lint)
  32 static char sccsid[] = "@(#)qsort.c     8.1 (Berkeley) 6/4/93";
  33 #endif /* LIBC_SCCS and not lint */
  34 #include <sys/cdefs.h>
  35 __FBSDID("$FreeBSD$");
  36 #endif
  37
  38 #include <config.h>
  39
  40 #ifdef NEED_QSORT
  41
  42 #include "roken.h"
  43
  44 #include <stdlib.h>
  45
  46 #ifdef I_AM_QSORT_R
  47 typedef int              cmp_t(void *, const void *, const void *);
  48 #else
  49 typedef int              cmp_t(const void *, const void *);
  50 #endif
  51 static inline char      *med3(char *, char *, char *, cmp_t *, void *);
  52 static inline void       swapfunc(char *, char *, int, int);
  53
  54 /*
  55  * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
  56  */
  57 #define swapcode(TYPE, parmi, parmj, n) {               \
  58         long i = (n) / sizeof (TYPE);                   \
  59         TYPE *pi = (TYPE *) (parmi);            \
  60         TYPE *pj = (TYPE *) (parmj);            \
  61         do {                                            \
  62                 TYPE    t = *pi;                \
  63                 *pi++ = *pj;                            \
  64                 *pj++ = t;                              \
  65         } while (--i > 0);                              \
  66 }
  67
  68 #define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
  69         es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;
  70
  71 static inline void
  72 swapfunc(a, b, n, swaptype)
  73         char *a, *b;
  74         int n, swaptype;
  75 {
  76         if(swaptype <= 1)
  77                 swapcode(long, a, b, n)
  78         else
  79                 swapcode(char, a, b, n)
  80 }
  81
  82 #define swap(a, b)                                      \
  83         if (swaptype == 0) {                            \
  84                 long t = *(long *)(a);                  \
  85                 *(long *)(a) = *(long *)(b);            \
  86                 *(long *)(b) = t;                       \
  87         } else                                          \
  88                 swapfunc(a, b, es, swaptype)
  89
  90 #define vecswap(a, b, n)        if ((n) > 0) swapfunc(a, b, n, swaptype)
  91
  92 #ifdef I_AM_QSORT_R
  93 #define CMP(t, x, y) (cmp((t), (x), (y)))
  94 #else
  95 #define CMP(t, x, y) (cmp((x), (y)))
  96 #endif
  97
  98 static inline char *
  99 med3(char *a, char *b, char *c, cmp_t *cmp, void *thunk
 100 #ifndef I_AM_QSORT_R
 101 /* __unused */
 102 #endif
 103 )
 104 {
 105         return CMP(thunk, a, b) < 0 ?
 106                (CMP(thunk, b, c) < 0 ? b : (CMP(thunk, a, c) < 0 ? c : a ))
 107               :(CMP(thunk, b, c) > 0 ? b : (CMP(thunk, a, c) < 0 ? a : c ));
 108 }
 109
 110 #ifdef I_AM_QSORT_R
 111 void
 112 rk_qsort_r(void *a, size_t n, size_t es, void *thunk, cmp_t *cmp)
 113 #else
 114 #define thunk NULL
 115 void
 116 rk_qsort(void *a, size_t n, size_t es, cmp_t *cmp)
 117 #endif
 118 {
 119         char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
 120         size_t d, r;
 121         int cmp_result;
 122         int swaptype, swap_cnt;
 123
 124 loop:   SWAPINIT(a, es);
 125         swap_cnt = 0;
 126         if (n < 7) {
 127                 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
 128                         for (pl = pm;
 129                              pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
 130                              pl -= es)
 131                                 swap(pl, pl - es);
 132                 return;
 133         }
 134         pm = (char *)a + (n / 2) * es;
 135         if (n > 7) {
 136                 pl = a;
 137                 pn = (char *)a + (n - 1) * es;
 138                 if (n > 40) {
 139                         d = (n / 8) * es;
 140                         pl = med3(pl, pl + d, pl + 2 * d, cmp, thunk);
 141                         pm = med3(pm - d, pm, pm + d, cmp, thunk);
 142                         pn = med3(pn - 2 * d, pn - d, pn, cmp, thunk);
 143                 }
 144                 pm = med3(pl, pm, pn, cmp, thunk);
 145         }
 146         swap(a, pm);
 147         pa = pb = (char *)a + es;
 148
 149         pc = pd = (char *)a + (n - 1) * es;
 150         for (;;) {
 151                 while (pb <= pc && (cmp_result = CMP(thunk, pb, a)) <= 0) {
 152                         if (cmp_result == 0) {
 153                                 swap_cnt = 1;
 154                                 swap(pa, pb);
 155                                 pa += es;
 156                         }
 157                         pb += es;
 158                 }
 159                 while (pb <= pc && (cmp_result = CMP(thunk, pc, a)) >= 0) {
 160                         if (cmp_result == 0) {
 161                                 swap_cnt = 1;
 162                                 swap(pc, pd);
 163                                 pd -= es;
 164                         }
 165                         pc -= es;
 166                 }
 167                 if (pb > pc)
 168                         break;
 169                 swap(pb, pc);
 170                 swap_cnt = 1;
 171                 pb += es;
 172                 pc -= es;
 173         }
 174         if (swap_cnt == 0) {  /* Switch to insertion sort */
 175                 for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)
 176                         for (pl = pm;
 177                              pl > (char *)a && CMP(thunk, pl - es, pl) > 0;
 178                              pl -= es)
 179                                 swap(pl, pl - es);
 180                 return;
 181         }
 182
 183         pn = (char *)a + n * es;
 184         r = min(pa - (char *)a, pb - pa);
 185         vecswap(a, pb - r, r);
 186         r = min(pd - pc, pn - pd - es);
 187         vecswap(pb, pn - r, r);
 188         if ((r = pb - pa) > es)
 189 #ifdef I_AM_QSORT_R
 190                 rk_qsort_r(a, r / es, es, thunk, cmp);
 191 #else
 192                 rk_qsort(a, r / es, es, cmp);
 193 #endif
 194         if ((r = pd - pc) > es) {
 195                 /* Iterate rather than recurse to save stack space */
 196                 a = pn - r;
 197                 n = r / es;
 198                 goto loop;
 199         }
 200 /*              rk_qsort(pn - r, r / es, es, cmp);*/
 201 }
 202
 203 #endif /* NEED_QSORT */