/* Pagemap manipulation for pager library
   Copyright (C) 1994, 1997, 1999, 2000 Free Software Foundation

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License as
   published by the Free Software Foundation; either version 2, or (at
   your option) any later version.

   This program is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */

#include "priv.h"
#include <stdlib.h>
#include <string.h>

/* Grow the pagemap of pager P as necessary to deal with address OFF */
error_t
_pager_pagemap_resize (struct pager *p, vm_address_t off)
{
  off /= __vm_page_size;

  if (p->pagemapsize < off)
    {
      void *newaddr = reallocarray (p->pagemap, off,
                                    sizeof (*p->pagemap));
      if (!newaddr)
        return errno;

      memset ((short *) newaddr + p->pagemapsize, 0,
              (off - p->pagemapsize) * sizeof (*p->pagemap));
      p->pagemap = newaddr;
      p->pagemapsize = off;
    }

  return 0;
}