LXR uboot/fs/yaffs2/yaffs

   1/*
   2 * Copyright (c) 1992, 1993
   3 *      The Regents of the University of California.  All rights reserved.
   4 *
   5 * SPDX-License-Identifier:     BSD-3-Clause
   6 */
   7
   8#include "yportenv.h"
   9/* #include <linux/string.h> */
  10
  11/*
  12 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".
  13 */
  14#define swapcode(TYPE, parmi, parmj, n) do {            \
  15        long i = (n) / sizeof(TYPE);                    \
  16        register TYPE *pi = (TYPE *) (parmi);           \
  17        register TYPE *pj = (TYPE *) (parmj);           \
  18        do {                                            \
  19                register TYPE   t = *pi;                \
  20                *pi++ = *pj;                            \
  21                *pj++ = t;                              \
  22        } while (--i > 0);                              \
  23} while (0)
  24
  25#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \
  26        es % sizeof(long) ? 2 : es == sizeof(long) ? 0 : 1;
  27
  28static inline void
  29swapfunc(char *a, char *b, int n, int swaptype)
  30{
  31        if (swaptype <= 1)
  32                swapcode(long, a, b, n);
  33        else
  34                swapcode(char, a, b, n);
  35}
  36
  37#define yswap(a, b) do {                                        \
  38        if (swaptype == 0) {                            \
  39                long t = *(long *)(a);                  \
  40                *(long *)(a) = *(long *)(b);            \
  41                *(long *)(b) = t;                       \
  42        } else                                          \
  43                swapfunc(a, b, es, swaptype);           \
  44} while (0)
  45
  46#define vecswap(a, b, n)        if ((n) > 0) swapfunc(a, b, n, swaptype)
  47
  48static inline char *
  49med3(char *a, char *b, char *c, int (*cmp)(const void *, const void *))
  50{
  51        return cmp(a, b) < 0 ?
  52                (cmp(b, c) < 0 ? b : (cmp(a, c) < 0 ? c : a))
  53                : (cmp(b, c) > 0 ? b : (cmp(a, c) < 0 ? a : c));
  54}
  55
  56#ifndef min
  57#define min(a, b) (((a) < (b)) ? (a) : (b))
  58#endif
  59
  60void
  61yaffs_qsort(void *aa, size_t n, size_t es,
  62        int (*cmp)(const void *, const void *))
  63{
  64        char *pa, *pb, *pc, *pd, *pl, *pm, *pn;
  65        int d, r, swaptype, swap_cnt;
  66        register char *a = aa;
  67
  68loop:   SWAPINIT(a, es);
  69        swap_cnt = 0;
  70        if (n < 7) {
  71                for (pm = (char *)a + es; pm < (char *) a + n * es; pm += es)
  72                        for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
  73                             pl -= es)
  74                                yswap(pl, pl - es);
  75                return;
  76        }
  77        pm = (char *)a + (n / 2) * es;
  78        if (n > 7) {
  79                pl = (char *)a;
  80                pn = (char *)a + (n - 1) * es;
  81                if (n > 40) {
  82                        d = (n / 8) * es;
  83                        pl = med3(pl, pl + d, pl + 2 * d, cmp);
  84                        pm = med3(pm - d, pm, pm + d, cmp);
  85                        pn = med3(pn - 2 * d, pn - d, pn, cmp);
  86                }
  87                pm = med3(pl, pm, pn, cmp);
  88        }
  89        yswap(a, pm);
  90        pa = pb = (char *)a + es;
  91
  92        pc = pd = (char *)a + (n - 1) * es;
  93        for (;;) {
  94                while (pb <= pc && (r = cmp(pb, a)) <= 0) {
  95                        if (r == 0) {
  96                                swap_cnt = 1;
  97                                yswap(pa, pb);
  98                                pa += es;
  99                        }
 100                        pb += es;
 101                }
 102                while (pb <= pc && (r = cmp(pc, a)) >= 0) {
 103                        if (r == 0) {
 104                                swap_cnt = 1;
 105                                yswap(pc, pd);
 106                                pd -= es;
 107                        }
 108                        pc -= es;
 109                }
 110                if (pb > pc)
 111                        break;
 112                yswap(pb, pc);
 113                swap_cnt = 1;
 114                pb += es;
 115                pc -= es;
 116        }
 117        if (swap_cnt == 0) {  /* Switch to insertion sort */
 118                for (pm = (char *) a + es; pm < (char *) a + n * es; pm += es)
 119                        for (pl = pm; pl > (char *) a && cmp(pl - es, pl) > 0;
 120                             pl -= es)
 121                                yswap(pl, pl - es);
 122                return;
 123        }
 124
 125        pn = (char *)a + n * es;
 126        r = min(pa - (char *)a, pb - pa);
 127        vecswap(a, pb - r, r);
 128        r = min((long)(pd - pc), (long)(pn - pd - es));
 129        vecswap(pb, pn - r, r);
 130        r = pb - pa;
 131        if (r > es)
 132                yaffs_qsort(a, r / es, es, cmp);
 133        r = pd - pc;
 134        if (r > es) {
 135                /* Iterate rather than recurse to save stack space */
 136                a = pn - r;
 137                n = r / es;
 138                goto loop;
 139        }
 140/*              yaffs_qsort(pn - r, r / es, es, cmp);*/
 141}
 142