lwip-contrib-mac/ports/unix/netif/list.c

/*
 * Copyright (c) 2001-2003 Swedish Institute of Computer Science.
 * 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. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission. 
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 *
 * This file is part of the lwIP TCP/IP stack.
 * 
 * Author: Adam Dunkels <adam@sics.se>
 *
 */



#include <stdlib.h>

struct list {
  struct elem *first, *last;
  int size, elems;
};

struct elem {
  struct elem *next;
  void *data;
};

/*-----------------------------------------------------------------------------------*/
struct list *
list_new(int size)
{
  struct list *list;
  list = malloc(sizeof(struct list));
  list->first = list->last = NULL;
  list->size = size;
  list->elems = 0;
  return list;
}
/*-----------------------------------------------------------------------------------*/
int
list_push(struct list *list, void *data)
{
  struct elem *elem;
  
  if(list->elems < list->size) {
    elem = malloc(sizeof(struct elem));
    elem->data = data;
    elem->next = NULL;
    if(list->last != NULL) {
      list->last->next = elem;
    }
    list->last = elem;
    if(list->first == NULL) {
      list->first = elem;
    }
    list->elems++;
    return 1;
  }
  return 0;
}
/*-----------------------------------------------------------------------------------*/
void *
list_pop(struct list *list)
{
  struct elem *elem;
  void *data;
  
  if(list->elems > 0) {    
    elem = list->first;
    if(elem == list->last) {
      list->last = elem->next;
    }
    list->first = elem->next;
    
    list->elems--;

    data = elem->data;
    free(elem);

    return data;
  }
  return NULL;
}
/*-----------------------------------------------------------------------------------*/
void *
list_first(struct list *list)
{
  return list->first;
}
/*-----------------------------------------------------------------------------------*/
int
list_elems(struct list *list)
{
  return list->elems;
}
/*-----------------------------------------------------------------------------------*/
void
list_delete(struct list *list)
{
  while(list_pop(list) != NULL);
  free(list);
}
/*-----------------------------------------------------------------------------------*/
int
list_remove(struct list *list, void *elem)
{
  struct elem *e, *p;
  
  p = NULL;
  for(e = list->first; e != NULL; e = e->next) {
    if(e->data == elem) {
      if(p != NULL) {
        p->next = e->next;
      } else {
        list->first = e->next;
      }
      if(list->last == e) {
        list->last = p;
        if(p != NULL) {
          p->next = NULL;
        }
      }
      free(e);
      list->elems--;
      return 1;
    } 
    p = e;    
  }
  return 0;
}
/*-----------------------------------------------------------------------------------*/
void
list_map(struct list *list, void (* func)(void *arg))
{
  struct elem *e;

  for(e = list->first; e != NULL; e = e->next) {
    func(e->data);
  }
}
/*-----------------------------------------------------------------------------------*/