Switching to std::sort

#include <climits>

#include <cstdlib>

#include <cstring>

#include <algorithm>

#include "style_atom.h"

#include "atom_vec.h"

#include "atom_vec_ellipsoid.h"

void Atom::add_callback(int flag)

{

  int ifix, i, j;

  int ifix;

  // find the fix

  // if find NULL ptr:

  for (ifix = 0; ifix < modify->nfix; ifix++)

    if (modify->fix[ifix] == NULL) break;

  // insert callback into sorted lists, reallocating if necessary

  // add callback to lists and sort, reallocating if necessary

  // sorting is required in cases where fixes were replaced as it ensures atom

  // data is read/written/transfered in the same order that fixes are called

      nextra_grow_max += DELTA;

      memory->grow(extra_grow,nextra_grow_max,"atom:extra_grow");

    }

    for(i = 0; i < nextra_grow; i++)

        if(ifix < extra_grow[i]) break;

    if(i == nextra_grow) {

    extra_grow[nextra_grow] = ifix;

    } else {

      for(j = nextra_grow; j > i; j--)

          extra_grow[j] = extra_grow[j-1];

      extra_grow[i] = ifix;

    }

    nextra_grow++;

    std::sort(extra_grow, extra_grow + nextra_grow);     

  } else if (flag == 1) {

    if (nextra_restart == nextra_restart_max) {

      nextra_restart_max += DELTA;

      memory->grow(extra_restart,nextra_restart_max,"atom:extra_restart");

    }

    for(i = 0; i < nextra_restart; i++)

        if(ifix < extra_restart[i]) break;

    if(i == nextra_restart) {

    extra_restart[nextra_restart] = ifix;

    } else {

      for(j = nextra_restart; j > i; j--)

          extra_restart[j] = extra_restart[j-1];

      extra_restart[i] = ifix;

    }     

    nextra_restart++;

    std::sort(extra_restart, extra_restart + nextra_restart);     

  } else if (flag == 2) {

    if (nextra_border == nextra_border_max) {

      nextra_border_max += DELTA;

      memory->grow(extra_border,nextra_border_max,"atom:extra_border");

    }

    for(i = 0; i < nextra_border; i++)

        if(ifix < extra_border[i]) break;

    if(i == nextra_border) {

    extra_border[nextra_border] = ifix;

    } else {

      for(j = nextra_border; j > i; j--)

          extra_border[j] = extra_border[j-1];

      extra_border[i] = ifix;

    }

    nextra_border++;

    std::sort(extra_border, extra_border + nextra_border);     

  }

}