/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */

/*-

 * Copyright (c) 1992, 1993

 *  The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

/* We need this because Solaris' version of qsort is broken and

 * causes array bounds reads.

 */

#include <stdlib.h>

#include "nsAlgorithm.h"

#include "nsQuickSort.h"

extern "C" {

#if !defined(DEBUG) && (defined(__cplusplus) || defined(__gcc))

# ifndef INLINE

#  define INLINE inline

# endif

#else

# define INLINE

#endif

typedef int    cmp_t(const void *, const void *, void *);

static INLINE char  *med3(char *, char *, char *, cmp_t *, void *);

static INLINE void  swapfunc(char *, char *, int, int);

/*

 * Qsort routine from Bentley & McIlroy's "Engineering a Sort Function".

 */

#define swapcode(TYPE, parmi, parmj, n) {     \

  long i = (n) / sizeof (TYPE);       \

  TYPE *pi = (TYPE *) (parmi);      \

  TYPE *pj = (TYPE *) (parmj);      \

  do {             \

    TYPE  t = *pi;      \

    *pi++ = *pj;        \

    *pj++ = t;        \

        } while (--i > 0);        \

}

#define SWAPINIT(a, es) swaptype = ((char *)a - (char *)0) % sizeof(long) || \

  es % sizeof(long) ? 2 : es == sizeof(long)? 0 : 1;

static INLINE void

swapfunc(char *a, char *b, int n, int swaptype)

{

  if(swaptype <= 1)

    swapcode(long, a, b, n)

  else

    swapcode(char, a, b, n)

}

#define swap(a, b)          \

  if (swaptype == 0) {       \

    long t = *(long *)(a);      \

    *(long *)(a) = *(long *)(b);    \

    *(long *)(b) = t;     \

  } else           \

    swapfunc((char *)a, (char*)b, (int)es, swaptype)

#define vecswap(a, b, n)  if ((n) > 0) swapfunc((char *)a, (char *)b, (int)n, swaptype)

static INLINE char *

med3(char *a, char *b, char *c, cmp_t* cmp, void *data)

{

  return cmp(a, b, data) < 0 ?

         (cmp(b, c, data) < 0 ? b : (cmp(a, c, data) < 0 ? c : a ))

              :(cmp(b, c, data) > 0 ? b : (cmp(a, c, data) < 0 ? a : c ));

}

void NS_QuickSort (

  void *a,

  unsigned int n,

    unsigned int es,

  cmp_t *cmp,

  void *data

    )

{

  char *pa, *pb, *pc, *pd, *pl, *pm, *pn;

  int d, r, swaptype;

loop: SWAPINIT(a, es);

  /* Use insertion sort when input is small */

  if (n < 7) {

    for (pm = (char *)a + es; pm < (char *)a + n * es; pm += es)

      for (pl = pm; pl > (char *)a && cmp(pl - es, pl, data) > 0;

           pl -= es)

        swap(pl, pl - es);

    return;

  }

  /* Choose pivot */

  pm = (char *)a + (n / 2) * es;

  if (n > 7) {

    pl = (char *)a;

    pn = (char *)a + (n - 1) * es;

    if (n > 40) {

      d = (n / 8) * es;

      pl = med3(pl, pl + d, pl + 2 * d, cmp, data);

      pm = med3(pm - d, pm, pm + d, cmp, data);

      pn = med3(pn - 2 * d, pn - d, pn, cmp, data);

    }

    pm = med3(pl, pm, pn, cmp, data);

  }

  swap(a, pm);

  pa = pb = (char *)a + es;

  pc = pd = (char *)a + (n - 1) * es;

  /* loop invariants:

   * [a, pa) = pivot

   * [pa, pb) < pivot

   * [pb, pc + es) unprocessed

   * [pc + es, pd + es) > pivot

   * [pd + es, pn) = pivot

   */

  for (;;) {

    while (pb <= pc && (r = cmp(pb, a, data)) <= 0) {

      if (r == 0) {

        swap(pa, pb);

        pa += es;

      }

      pb += es;

    }

    while (pb <= pc && (r = cmp(pc, a, data)) >= 0) {

      if (r == 0) {

        swap(pc, pd);

        pd -= es;

      }

      pc -= es;

    }

    if (pb > pc)

      break;

    swap(pb, pc);

    pb += es;

    pc -= es;

  }

  /* Move pivot values */

  pn = (char *)a + n * es;

  r = XPCOM_MIN(pa - (char *)a, pb - pa);

  vecswap(a, pb - r, r);

  r = XPCOM_MIN<size_t>(pd - pc, pn - pd - es);

  vecswap(pb, pn - r, r);

  /* Recursively process partitioned items */

  if ((r = pb - pa) > (int)es)

        NS_QuickSort(a, r / es, es, cmp, data);

  if ((r = pd - pc) > (int)es) {

    /* Iterate rather than recurse to save stack space */

    a = pn - r;

    n = r / es;

    goto loop;

  }

/*    NS_QuickSort(pn - r, r / es, es, cmp, data);*/

}

}

#undef INLINE

#undef swapcode

#undef SWAPINIT

#undef swap

#undef vecswap