LXR uboot/fs/yaffs2/yaffs

   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 * 3. 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#include "yportenv.h"
  31/* #include <linux/string.h> */
  32
  33/*
  34 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
  35 */
  36#define swapcode(TYPE, parmi, parmj, n) do {            \
  37        long i = (n) / sizeof(TYPE);                    \
  38        register TYPE *pi = (TYPE *) (parmi);           \
  39        register TYPE *pj = (TYPE *) (parmj);           \
  40        do {                                            \
  41                register TYPE   t = *pi;                \
  42                *pi++ = *pj;                            \
  43                *pj++ = t;                              \
  44        } while (--i > 0);                              \
  45} while (0)
  46
  47#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
  48        es % sizeof(long) ? 2 : es == sizeof(long) ? 0 : 1;
  49
  50static inline void
  51swapfunc(char *a, char *b, int n, int swaptype)
  52{
  53        if (swaptype <= 1)
  54                swapcode(long, a, b, n);
  55        else
  56                swapcode(char, a, b, n);
  57}
  58
  59#define yswap(a, b) do {                                        \
  60        if (swaptype == 0) {                            \
  61                long t = *(long *)(a);                  \
  62                *(long *)(a) = *(long *)(b);            \
  63                *(long *)(b) = t;                       \
  64        } else                                          \
  65                swapfunc(a, b, es, swaptype);           \
  66} while (0)
  67
  68#define vecswap(a, b, n)        if ((n) > 0) swapfunc(a, b, n, swaptype)
  69
  70static inline char *
  71med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
  72{
  73        return cmp(a, b) < 0 ?
  74                (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a))
  75                : (cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c));
  76}
  77
  78#ifndef min
  79#define min(a, b) (((a) < (b)) ? (a) : (b))
  80#endif
  81
  82void
  83yaffs_qsort(void *aa, size_t n, size_t es,
  84        int (*cmp)(const void *, const void *))
  85{
  86        char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
  87        int d, r, swaptype, swap_cnt;
  88        register char *a = aa;
  89
  90loop:   SWAPINIT(a, es);
  91        swap_cnt = 0;
  92        if (n < 7) {
  93                for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
  94                        for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
  95                             pl -= es)
  96                                yswap(pl, pl - es);
  97                return;
  98        }
  99        pm = (char *)a + (n / 2) * es;
 100        if (n > 7) {
 101                pl = (char *)a;
 102                pn = (char *)a + (n - 1) * es;
 103                if (n > 40) {
 104                        d = (n / 8) * es;
 105                        pl = med3(pl, pl + d, pl + 2 * d, cmp);
 106                        pm = med3(pm - d, pm, pm + d, cmp);
 107                        pn = med3(pn - 2 * d, pn - d, pn, cmp);
 108                }
 109                pm = med3(pl, pm, pn, cmp);
 110        }
 111        yswap(a, pm);
 112        pa = pb = (char *)a + es;
 113
 114        pc = pd = (char *)a + (n - 1) * es;
 115        for (;;) {
 116                while (pb <= pc && (r = cmp(pb, a)) <= 0) {
 117                        if (r == 0) {
 118                                swap_cnt = 1;
 119                                yswap(pa, pb);
 120                                pa += es;
 121                        }
 122                        pb += es;
 123                }
 124                while (pb <= pc && (r = cmp(pc, a)) >= 0) {
 125                        if (r == 0) {
 126                                swap_cnt = 1;
 127                                yswap(pc, pd);
 128                                pd -= es;
 129                        }
 130                        pc -= es;
 131                }
 132                if (pb > pc)
 133                        break;
 134                yswap(pb, pc);
 135                swap_cnt = 1;
 136                pb += es;
 137                pc -= es;
 138        }
 139        if (swap_cnt == 0) {  /* Switch to insertion sort */
 140                for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
 141                        for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
 142                             pl -= es)
 143                                yswap(pl, pl - es);
 144                return;
 145        }
 146
 147        pn = (char *)a + n * es;
 148        r = min(pa - (char *)a, pb - pa);
 149        vecswap(a, pb - r, r);
 150        r = min((long)(pd - pc), (long)(pn - pd - es));
 151        vecswap(pb, pn - r, r);
 152        r = pb - pa;
 153        if (r > es)
 154                yaffs_qsort(a, r / es, es, cmp);
 155        r = pd - pc;
 156        if (r > es) {
 157                /* Iterate rather than recurse to save stack space */
 158                a = pn - r;
 159                n = r / es;
 160                goto loop;
 161        }
 162/*              yaffs_qsort(pn - r, r / es, es, cmp);*/
 163}
 164