text: /*
   * Copyright (c) 2004, 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. Neither the name of the Institute 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 INSTITUTE 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 INSTITUTE 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.
   *
   * This file is part of the Contiki operating system.
   *
   * Author: Adam Dunkels <adam@sics.se>
   *
   */
  
  /**
   * \file
   * Linked list manipulation routines.
   * \author Adam Dunkels <adam@sics.se>
   *
   */
  
  /** \addtogroup lib
      @{ */
  /**
   * \defgroup list Linked list library
   *
   * The linked list library provides a set of functions for
   * manipulating linked lists.
   *
   * A linked list is made up of elements where the first element \b
   * must be a pointer. This pointer is used by the linked list library
   * to form lists of the elements.
   *
   * Lists are declared with the LIST() macro. The declaration specifies
   * the name of the list that later is used with all list functions.
   *
   * Lists can be manipulated by inserting or removing elements from
   * either sides of the list (list_push(), list_add(), list_pop(),
   * list_chop()). A specified element can also be removed from inside a
   * list with list_remove(). The head and tail of a list can be
   * extracted using list_head() and list_tail(), respectively.
   *
   * @{
   */
  
  #ifndef LIST_H_
  #define LIST_H_
  
  #define LIST_CONCAT2(s1, s2) s1##s2
  #define LIST_CONCAT(s1, s2) LIST_CONCAT2(s1, s2)
  
  /**
   * Declare a linked list.
   *
   * This macro declares a linked list with the specified \c type. The
   * type \b must be a structure (\c struct) with its first element
   * being a pointer. This pointer is used by the linked list library to
   * form the linked lists.
   *
   * The list variable is declared as static to make it easy to use in a
   * single C module without unnecessarily exporting the name to other
   * modules. 
   *
   * \param name The name of the list.
   */
  #define LIST(name) \
           static void *LIST_CONCAT(name,_list) = NULL; \
           static list_t name = (list_t)&LIST_CONCAT(name,_list)
  
  /**
   * Declare a linked list inside a structure declaraction.
   *
   * This macro declares a linked list with the specified \c type. The
   * type \b must be a structure (\c struct) with its first element
   * being a pointer. This pointer is used by the linked list library to
   * form the linked lists.
   *
   * Internally, the list is defined as two items: the list itself and a
   * pointer to the list. The pointer has the name of the parameter to
   * the macro and the name of the list is a concatenation of the name
   * and the suffix "_list". The pointer must point to the list for the
   * list to work. Thus the list must be initialized before using.
   *
   * The list is initialized with the LIST_STRUCT_INIT() macro.
   *
   * \param name The name of the list.
   */
  #define LIST_STRUCT(name) \
           void *LIST_CONCAT(name,_list); \
           list_t name
  
  /**
   * Initialize a linked list that is part of a structure.
   *
   * This macro sets up the internal pointers in a list that has been
   * defined as part of a struct. This macro must be called before using
   * the list.
   *
   * \param struct_ptr A pointer to the struct
   * \param name The name of the list.
   */
  #define LIST_STRUCT_INIT(struct_ptr, name)                              \
      do {                                                                \
         (struct_ptr)->name = &((struct_ptr)->LIST_CONCAT(name,_list));   \
         (struct_ptr)->LIST_CONCAT(name,_list) = NULL;                    \
         list_init((struct_ptr)->name);                                   \
      } while(0)
  
  /**
   * The linked list type.
   *
   */
  typedef void ** list_t;
  
  void   list_init(list_t list);
  void * list_head(list_t list);
  void * list_tail(list_t list);
  void * list_pop (list_t list);
  void   list_push(list_t list, void *item);
  
  void * list_chop(list_t list);
  
  void   list_add(list_t list, void *item);
  void   list_remove(list_t list, void *item);
  
  int    list_length(list_t list);
  
  void   list_copy(list_t dest, list_t src);
  
  void   list_insert(list_t list, void *previtem, void *newitem);
  
  void * list_item_next(void *item);
  
  #endif /* LIST_H_ */
  
  /** @} */
  /** @} */
  