Import of the contiki-2.x development code from the SICS internal CVS server

core/lib/list.c

@@ -0,0 +1,306 @@
+/**
+ * \addtogroup list
+ * @{
+ */
+
+/**
+ * \file
+ * Linked list library implementation.
+ *
+ * \author Adam Dunkels <adam@sics.se>
+ *
+ */
+
+/*
+ * 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>
+ *
+ * $Id: list.c,v 1.1 2006/06/17 22:41:18 adamdunkels Exp $
+ */
+#include "lib/list.h"
+
+#define NULL 0
+
+struct list {
+  struct list *next;
+};
+
+/*---------------------------------------------------------------------------*/
+/**
+ * Initialize a list.
+ *
+ * This function initalizes a list. The list will be empty after this
+ * function has been called.
+ *
+ * \param list The list to be initialized.
+ */
+void
+list_init(list_t list)
+{
+  *list = NULL;
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * Get a pointer to the first element of a list.
+ *
+ * This function returns a pointer to the first element of the
+ * list. The element will \b not be removed from the list.
+ *
+ * \param list The list.
+ * \return A pointer to the first element on the list.
+ *
+ * \sa list_tail()
+ */
+void *
+list_head(list_t list)
+{
+  return *list;
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * Duplicate a list.
+ *
+ * This function duplicates a list by copying the list reference, but
+ * not the elements.
+ *
+ * \note This function does \b not copy the elements of the list, but
+ * merely duplicates the pointer to the first element of the list.
+ *
+ * \param dest The destination list.
+ * \param src The source list.
+ */
+void
+list_copy(list_t dest, list_t src)
+{
+  *dest = *src;
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * Get the tail of a list.
+ *
+ * This function returns a pointer to the elements following the first
+ * element of a list. No elements are removed by this function.
+ *
+ * \param list The list
+ * \return A pointer to the element after the first element on the list.
+ *
+ * \sa list_head()
+ */
+void *
+list_tail(list_t list)
+{
+  struct list *l;
+  
+  if(*list == NULL) {
+    return NULL;
+  }
+  
+  for(l = *list; l->next != NULL; l = l->next);
+  
+  return l;
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * Add an item at the end of a list.
+ *
+ * This function adds an item to the end of the list.
+ *
+ * \param list The list.
+ * \param item A pointer to the item to be added.
+ *
+ * \sa list_push()
+ *
+ */
+void
+list_add(list_t list, void *item)
+{
+  struct list *l;
+
+  ((struct list *)item)->next = NULL;
+  
+  l = list_tail(list);
+
+  if(l == NULL) {
+    *list = item;
+  } else {
+    l->next = item;
+  }
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * Add an item to the start of the list.
+ */
+void
+list_push(list_t list, void *item)
+{
+  /*  struct list *l;*/
+
+  ((struct list *)item)->next = *list;
+  *list = item;
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * Remove the last object on the list.
+ *
+ * This function removes the last object on the list and returns it.
+ *
+ * \param list The list
+ * \return The removed object
+ *
+ */
+void *
+list_chop(list_t list)
+{
+  struct list *l, *r;
+  
+  if(*list == NULL) {
+    return NULL;
+  }
+  if(((struct list *)*list)->next == NULL) {
+    l = *list;
+    *list = NULL;
+    return l;
+  }
+  
+  for(l = *list; l->next->next != NULL; l = l->next);
+
+  r = l->next;
+  l->next = NULL;
+  
+  return r;
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * Remove the first object on a list.
+ *
+ * This function removes the first object on the list and returns a
+ * pointer to the list.
+ *
+ * \param list The list.
+ * \return The new head of the list.
+ */
+/*---------------------------------------------------------------------------*/
+void *
+list_pop(list_t list)
+{
+  if(*list != NULL) {
+    *list = ((struct list *)*list)->next;
+  }
+
+  return *list;
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * Remove a specific element from a list.
+ *
+ * This function removes a specified element from the list.
+ *
+ * \param list The list.
+ * \param item The item that is to be removed from the list.
+ *
+ */
+/*---------------------------------------------------------------------------*/
+void
+list_remove(list_t list, void *item)
+{
+  struct list *l, *r;
+  
+  if(*list == NULL) {
+    return;
+  }
+  
+  r = NULL;
+  for(l = *list; l != NULL; l = l->next) {
+    if(l == item) {
+      if(r == NULL) {
+	/* First on list */
+	*list = l->next;
+      } else {
+	/* Not first on list */
+	r->next = l->next;
+      }
+      l->next = NULL;
+      return;
+    }
+    r = l;
+  }
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * Get the length of a list.
+ *
+ * This function counts the number of elements on a specified list.
+ *
+ * \param list The list.
+ * \return The length of the list.
+ */
+/*---------------------------------------------------------------------------*/
+int
+list_length(list_t list)
+{
+  struct list *l;
+  int n = 0;
+
+  for(l = *list; l != NULL; l = l->next) {
+    ++n;
+  }
+
+  return n;
+}
+/*---------------------------------------------------------------------------*/
+/**
+ * \brief      Insert an item after a specified item on the list
+ * \param list The list
+ * \param previtem The item after which the new item should be inserted
+ * \param newitem  The new item that is to be inserted
+ * \author     Adam Dunkels
+ *
+ *             This function inserts an item right after a specified
+ *             item on the list. This function is useful when using
+ *             the list module to ordered lists.
+ *
+ *             If previtem is NULL, the new item is placed at the
+ *             start of the list.
+ *
+ */
+void
+list_insert(list_t list, void *previtem, void *newitem)
+{
+  if(previtem == NULL) {
+    list_push(list, newitem);
+  } else {
+  
+    ((struct list *)newitem)->next = ((struct list *)previtem)->next;
+    ((struct list *)previtem)->next = newitem;
+  }
+}
+/*---------------------------------------------------------------------------*/
+/** @} */