Take linked list implementation from SimpleOS

core/list.h

@@ -0,0 +1,194 @@
+/* Copyright (C) 2001  David Decotigny
+ 
+   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
+   of the License, 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
+   USA.
+*/
+#ifndef _SOS_LIST_H_
+#define _SOS_LIST_H_
+
+/**
+ * @file list.h
+ *
+ * Circular doubly-linked lists implementation entirely based on C
+ * macros
+ */
+
+
+/* *_named are used when next and prev links are not exactly next
+   and prev. For instance when we have next_in_team, prev_in_team,
+   prev_global and next_global */
+
+#define list_init_named(list,prev,next) \
+  ((list) = NULL)
+
+#define list_singleton_named(list,item,prev,next) ({ \
+  (item)->next = (item)->prev = (item); \
+  (list) = (item); \
+})
+
+#define list_is_empty_named(list,prev,next) \
+  ((list) == NULL)
+
+#define list_is_singleton_named(list,prev,next) \
+  ( ((list) != NULL) && ((list)->prev == (list)->next) && ((list) == (list)->next) )
+
+#define list_get_head_named(list,prev,next) \
+  (list)
+
+#define list_get_tail_named(list,prev,next) \
+  ((list)?((list)->prev):NULL)
+
+/* Internal macro : insert before the head == insert at tail */
+#define __list_insert_atleft_named(before_this,item,prev,next) ({ \
+   (before_this)->prev->next = (item); \
+   (item)->prev = (before_this)->prev; \
+   (before_this)->prev = (item); \
+   (item)->next = (before_this); \
+})
+
+/* @note Before_this and item are expected to be valid ! */
+#define list_insert_before_named(list,before_this,item,prev,next) ({ \
+   __list_insert_atleft_named(before_this,item,prev,next); \
+   if ((list) == (before_this)) (list) = (item); \
+})    
+
+/** @note After_this and item are expected to be valid ! */
+#define list_insert_after_named(list,after_this,item,prev,next) ({ \
+   (after_this)->next->prev = (item); \
+   (item)->next = (after_this)->next; \
+   (after_this)->next = (item); \
+   (item)->prev = (after_this); \
+})
+
+#define list_add_head_named(list,item,prev,next) ({ \
+  if (list) \
+    list_insert_before_named(list,list,item,prev,next); \
+  else \
+    list_singleton_named(list,item,prev,next); \
+  (list) = (item); \
+})
+
+#define list_add_tail_named(list,item,prev,next) ({ \
+  if (list) \
+    __list_insert_atleft_named(list,item,prev,next); \
+  else \
+    list_singleton_named(list,item,prev,next); \
+})
+
+/** @note NO check whether item really is in list ! */
+#define list_delete_named(list,item,prev,next) ({ \
+  if ( ((item)->next == (item)) && ((item)->prev == (item)) ) \
+    (item)->next = (item)->prev = (list) = NULL; \
+  else { \
+    (item)->prev->next = (item)->next; \
+    (item)->next->prev = (item)->prev; \
+    if ((item) == (list)) (list) = (item)->next; \
+    (item)->prev = (item)->next = NULL; \
+  } \
+})
+
+#define list_pop_head_named(list,prev,next) ({ \
+  typeof(list) __ret_elt = (list); \
+  list_delete_named(list,__ret_elt,prev,next); \
+  __ret_elt; })
+
+/** Loop statement that iterates through all of its elements, from
+    head to tail */
+#define list_foreach_forward_named(list,iterator,nb_elements,prev,next) \
+        for (nb_elements=0, (iterator) = (list) ; \
+             (iterator) && (!nb_elements || ((iterator) != (list))) ; \
+             nb_elements++, (iterator) = (iterator)->next )
+
+/** Loop statement that iterates through all of its elements, from
+    tail back to head */
+#define list_foreach_backward_named(list,iterator,nb_elements,prev,next) \
+        for (nb_elements=0, (iterator) = list_get_tail_named(list,prev,next) ; \
+             (iterator) && (!nb_elements || \
+               ((iterator) != list_get_tail_named(list,prev,next))) ; \
+             nb_elements++, (iterator) = (iterator)->prev )
+
+#define list_foreach_named list_foreach_forward_named
+
+/** True when we exitted early from the foreach loop (ie break) */
+#define list_foreach_early_break(list,iterator,nb_elements) \
+  ((list) && ( \
+    ((list) != (iterator)) || \
+    ( ((list) == (iterator)) && (nb_elements == 0)) ))
+
+/** Loop statement that also removes the item at each iteration. The
+    body of the loop is allowed to delete the iterator element from
+    memory. */
+#define list_collapse_named(list,iterator,prev,next) \
+        for ( ; ({ ((iterator) = (list)) ; \
+                   if (list) list_delete_named(list,iterator,prev,next) ; \
+                   (iterator); }) ; )
+
+
+/*
+ * the same macros : assume that the prev and next fields are really
+ * named "prev" and "next"
+ */
+
+#define list_init(list) \
+  list_init_named(list,prev,next)
+
+#define list_singleton(list,item) \
+  list_singleton_named(list,item,prev,next)
+
+#define list_is_empty(list) \
+  list_is_empty_named(list,prev,next)
+
+#define list_is_singleton(list) \
+  list_is_singleton_named(list,prev,next)
+
+#define list_get_head(list) \
+  list_get_head_named(list,prev,next) \
+
+#define list_get_tail(list) \
+  list_get_tail_named(list,prev,next) \
+
+/* @note Before_this and item are expected to be valid ! */
+#define list_insert_after(list,after_this,item) \
+  list_insert_after_named(list,after_this,item,prev,next)
+
+/* @note After_this and item are expected to be valid ! */
+#define list_insert_before(list,before_this,item) \
+  list_insert_before_named(list,before_this,item,prev,next)
+
+#define list_add_head(list,item) \
+  list_add_head_named(list,item,prev,next)
+
+#define list_add_tail(list,item) \
+  list_add_tail_named(list,item,prev,next)
+
+/* @note NO check whether item really is in list ! */
+#define list_delete(list,item) \
+  list_delete_named(list,item,prev,next)
+
+#define list_pop_head(list) \
+  list_pop_head_named(list,prev,next)
+
+#define list_foreach_forward(list,iterator,nb_elements) \
+  list_foreach_forward_named(list,iterator,nb_elements,prev,next)
+
+#define list_foreach_backward(list,iterator,nb_elements) \
+  list_foreach_backward_named(list,iterator,nb_elements,prev,next)
+
+#define list_foreach list_foreach_forward
+
+#define list_collapse(list,iterator) \
+  list_collapse_named(list,iterator,prev,next)
+
+#endif /* _SOS_LIST_H_ */