prepend.c 1.43 KB
/* GNU Mailutils -- a suite of utilities for electronic mail
   Copyright (C) 1999-2001, 2004-2005, 2007-2008, 2010-2012, 2014-2015
   Free Software Foundation, Inc.

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 3 of the License, or (at your option) any later version.

   This library 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General
   Public License along with this library.  If not, see 
   <http://www.gnu.org/licenses/>. */

#ifdef HAVE_CONFIG_H
# include <config.h>
#endif

#include <stdlib.h>
#include <mailutils/sys/list.h>
#include <mailutils/errno.h>

int
mu_list_prepend (mu_list_t list, void *item)
{
  struct list_data *ldata;
  struct list_data *first;

  if (list == NULL)
    return EINVAL;
  first = list->head.next;
  ldata = calloc (sizeof (*ldata), 1);
  if (ldata == NULL)
    return ENOMEM;
  ldata->item = item;
  mu_monitor_wrlock (list->monitor);
  ldata->prev = &list->head;
  ldata->next = list->head.next;
  first->prev = ldata;
  list->head.next = ldata;
  list->count++;
  mu_monitor_unlock (list->monitor);
  return 0;
}