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bertos/struct/list.h

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+/**
+ * \file
+ * <!--
+ * This file is part of BeRTOS.
+ *
+ * Bertos 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ * As a special exception, you may use this file as part of a free software
+ * library without restriction.  Specifically, if other files instantiate
+ * templates or use macros or inline functions from this file, or you compile
+ * this file and link it with other files to produce an executable, this
+ * file does not by itself cause the resulting executable to be covered by
+ * the GNU General Public License.  This exception does not however
+ * invalidate any other reasons why the executable file might be covered by
+ * the GNU General Public License.
+ *
+ * Copyright 2003, 2004 Develer S.r.l. (http://www.develer.com/)
+ * Copyright 2001, 2008 Bernie Innocenti <bernie@codewiz.org>
+ * -->
+ *
+ * \defgroup list General purpose lists
+ * \ingroup struct
+ * \{
+ *
+ * \brief General pourpose double-linked lists
+ *
+ * Lists contain nodes. You can put any custom struct into any list as long
+ * as it has a Node struct inside it. If you make the Node struct the first
+ * member of your data type, you can simply cast it to (Node *) when passing
+ * it to list functions.
+ *
+ * Lists must be initialized before use with LIST_INIT(). You can then add
+ * objects using ADDHEAD() and ADDTAIL() macros, and remove them with
+ * list_remHead() and list_remTail().
+ *
+ * You can create lists with priorities by using PriNode instead of Node as
+ * the base member struct.
+ * Use LIST_ENQUEUE() and LIST_ENQUEUE_HEAD() to insert a priority node into
+ * a list.
+ *
+ * To iterate over a list, use the macros FOREACH_NODE() and REVERSE_FOREACH_NODE()
+ * in this way:
+ * \code
+ * struct Foo
+ * {
+ *     Node n;
+ *     int a;
+ * }
+ *
+ * int main()
+ * {
+ *        List foo_list;
+ *        static Foo foo1, foo2;
+ *        Foo *fp;
+ *
+ *        LIST_INIT(&foo_list);
+ *        ADDHEAD(&foo_list, (Node *)&foo1);
+ *        INSERT_BEFORE(&foo_list, (Node *)&foo2);
+ *        FOREACH_NODE(fp, &foo_list)
+ *            fp->a = 10;
+ * }
+ * \endcode
+ *
+ * \author Bernie Innocenti <bernie@codewiz.org>
+ */
+
+#ifndef STRUCT_LIST_H
+#define STRUCT_LIST_H
+
+#include <cfg/compiler.h> /* INLINE */
+#include <cfg/debug.h> /* ASSERT_VALID_PTR() */
+
+/**
+ * This structure represents a node for bidirectional lists.
+ *
+ * Data is usually appended to nodes by making them the first
+ * field of another struture, as a poor-man's form of inheritance.
+ */
+typedef struct _Node
+{
+	struct _Node *succ;
+	struct _Node *pred;
+} Node;
+
+/**
+ * Head of a doubly-linked list of \c Node structs.
+ *
+ * Lists must be initialized with LIST_INIT() prior to use.
+ *
+ * Nodes can be added and removed from either end of the list
+ * with O(1) performance.  Iterating over these lists can be
+ * tricky: use the FOREACH_NODE() macro instead.
+ */
+typedef struct _List
+{
+	Node head;
+	Node tail;
+} List;
+
+/**
+ * Extended node for priority queues.
+ */
+typedef struct _PriNode
+{
+	Node link;
+	int  pri;
+} PriNode;
+
+
+/**
+ * Template for a naked node in a list of \a T structures.
+ *
+ * To be used as data member in other structures:
+ *
+ * \code
+ *    struct Foo
+ *    {
+ *        DECLARE_NODE_ANON(struct Foo)
+ *        int a;
+ *        float b;
+ *    }
+ *
+ *    DECLARE_LIST_TYPE(Foo);
+ *
+ *    void foo(void)
+ *    {
+ *        static LIST_TYPE(Foo) foo_list;
+ *        static Foo foo1, foo2;
+ *        Foo *fp;
+ *
+ *        LIST_INIT(&foo_list);
+ *        ADDHEAD(&foo_list, &foo1);
+ *        INSERT_BEFORE(&foo_list, &foo2);
+ *        FOREACH_NODE(fp, &foo_list)
+ *            fp->a = 10;
+ *    }
+ *
+ * \endcode
+ */
+#define DECLARE_NODE_ANON(T) \
+	T *succ; T *pred;
+
+/** Declare a typesafe node for structures of type \a T. */
+#define DECLARE_NODE_TYPE(T) \
+	typedef struct T##Node { T *succ; T *pred; } T##Node
+
+/** Template for a list of \a T structures. */
+#define DECLARE_LIST_TYPE(T) \
+	DECLARE_NODE_TYPE(T); \
+	typedef struct T##List { \
+		 T##Node head; \
+		 T##Node tail; \
+	} T##List
+
+#define NODE_TYPE(T) T##Node
+#define LIST_TYPE(T) T##List
+
+/**
+ * Get a pointer to the first node in a list.
+ *
+ * If \a l is empty, result points to l->tail.
+ */
+#define LIST_HEAD(l) ((l)->head.succ)
+
+/**
+ * Get a pointer to the last node in a list.
+ *
+ * If \a l is empty, result points to l->head.
+ */
+#define LIST_TAIL(l) ((l)->tail.pred)
+
+// TODO: move in compiler.h
+#if COMPILER_TYPEOF
+	#define TYPEOF_OR_VOIDPTR(type) typeof(type)
+#else
+	#define TYPEOF_OR_VOIDPTR(type) void *
+#endif
+
+/**
+ * Iterate over all nodes in a list.
+ *
+ * This macro generates a "for" statement using the following parameters:
+ * \param n   Node pointer to be used in each iteration.
+ * \param l   Pointer to list.
+ */
+#define FOREACH_NODE(n, l) \
+	for( \
+		(n) = (TYPEOF_OR_VOIDPTR(n))LIST_HEAD(l); \
+		((Node *)(n))->succ; \
+		(n) = (TYPEOF_OR_VOIDPTR(n))(((Node *)(n))->succ) \
+	)
+
+/**
+ * Iterate backwards over all nodes in a list.
+ *
+ * This macro generates a "for" statement using the following parameters:
+ * \param n   Node pointer to be used in each iteration.
+ * \param l   Pointer to list.
+ */
+#define REVERSE_FOREACH_NODE(n, l) \
+	for( \
+		(n) = (TYPEOF_OR_VOIDPTR(n))LIST_TAIL(l); \
+		((Node *)(n))->pred; \
+		(n) = (TYPEOF_OR_VOIDPTR(n))(((Node *)(n))->pred) \
+	)
+
+/**
+ * Iterate on the list safely against node removal.
+ *
+ * This macro generates a "for" statement using the following parameters:
+ * \param n   Node pointer to be used in each iteration.
+ * \param p   Temporal storage for the iterator.
+ * \param l   Pointer to list.
+ */
+#define FOREACH_NODE_SAFE(n, p, l) \
+	for( \
+		(n) = (TYPEOF_OR_VOIDPTR(n))LIST_HEAD(l), (p) = ((Node *)(n))->succ; \
+		((Node *)(n))->succ; \
+		(n) = (p), (p) = (TYPEOF_OR_VOIDPTR(n))(((Node *)(n))->succ) \
+	)
+
+/** Initialize a list. */
+#define LIST_INIT(l) \
+	do { \
+		(l)->head.succ = (TYPEOF_OR_VOIDPTR((l)->head.succ)) &(l)->tail; \
+		(l)->head.pred = NULL; \
+		(l)->tail.succ = NULL; \
+		(l)->tail.pred = (TYPEOF_OR_VOIDPTR((l)->tail.pred)) &(l)->head; \
+	} while (0)
+
+#ifdef _DEBUG
+	/** Make sure that a list is valid (it was initialized and is not corrupted). */
+	#define LIST_ASSERT_VALID(l) \
+		do { \
+			Node *n, *pred; \
+			ASSERT((l)->head.succ != NULL); \
+			ASSERT((l)->head.pred == NULL); \
+			ASSERT((l)->tail.succ == NULL); \
+			ASSERT((l)->tail.pred != NULL); \
+			pred = &(l)->head; \
+			FOREACH_NODE(n, l) \
+			{ \
+				ASSERT(n->pred == pred); \
+				pred = n; \
+			} \
+			ASSERT(n == &(l)->tail); \
+		} while (0)
+
+	/// Checks that a node isn't part of a given list
+	#define LIST_ASSERT_NOT_CONTAINS(list,node) \
+		do { \
+			Node *ln; \
+			ASSERT_VALID_PTR(list); \
+			ASSERT_VALID_PTR(node); \
+			FOREACH_NODE(ln, list) \
+				ASSERT(ln != (Node *)(node)); \
+		} while (0)
+
+	#define INVALIDATE_NODE(n) ((n)->succ = (n)->pred = NULL)
+#else
+	#define LIST_ASSERT_VALID(l) do {} while (0)
+	#define LIST_ASSERT_NOT_CONTAINS(list,node) do {} while (0)
+	#define INVALIDATE_NODE(n) do {} while (0)
+#endif
+
+/** Tell whether a list is empty. */
+#define LIST_EMPTY(l)  ( (void *)((l)->head.succ) == (void *)(&(l)->tail) )
+
+/** Add node to list head. */
+#define ADDHEAD(l,n) \
+	do { \
+		LIST_ASSERT_NOT_CONTAINS((l),(n)); \
+		(n)->succ = (l)->head.succ; \
+		(n)->pred = (l)->head.succ->pred; \
+		(n)->succ->pred = (n); \
+		(n)->pred->succ = (n); \
+	} while (0)
+
+/** Add node to list tail. */
+#define ADDTAIL(l,n) \
+	do { \
+		LIST_ASSERT_NOT_CONTAINS((l),(n)); \
+		(n)->succ = &(l)->tail; \
+		(n)->pred = (l)->tail.pred; \
+		(n)->pred->succ = (n); \
+		(l)->tail.pred = (n); \
+	} while (0)
+
+/**
+ * Insert node \a n before node \a ln.
+ *
+ * \note You can't pass in a list header as \a ln, but
+ *       it is safe to pass list-\>head of an empty list.
+ */
+#define INSERT_BEFORE(n,ln) \
+	do { \
+		ASSERT_VALID_PTR(n); \
+		ASSERT_VALID_PTR(ln); \
+		(n)->succ = (ln); \
+		(n)->pred = (ln)->pred; \
+		(ln)->pred->succ = (n); \
+		(ln)->pred = (n); \
+	} while (0)
+
+/**
+ * Remove \a n from whatever list it is in.
+ *
+ * \note Removing a node that has not previously been
+ *       inserted into a list invokes undefined behavior.
+ */
+#define REMOVE(n) \
+	do { \
+		ASSERT_VALID_PTR(n); \
+		(n)->pred->succ = (n)->succ; \
+		(n)->succ->pred = (n)->pred; \
+		INVALIDATE_NODE(n); \
+	} while (0)
+
+/**
+ * Insert a priority node in a priority queue.
+ *
+ * The new node is inserted immediately before the first node with the same
+ * priority or appended to the tail if no such node exists.
+ */
+#define LIST_ENQUEUE_HEAD(list, node) \
+	do { \
+		PriNode *ln; \
+		LIST_ASSERT_NOT_CONTAINS((list),(node)); \
+		FOREACH_NODE(ln, (list)) \
+			if (ln->pri <= (node)->pri) \
+				break; \
+		INSERT_BEFORE(&(node)->link, &ln->link); \
+	} while (0)
+
+/**
+ * Insert a priority node in a priority queue.
+ *
+ * The new node is inserted immediately before the first node with lower
+ * priority or appended to the tail if no such node exists.
+ */
+#define LIST_ENQUEUE(list, node) \
+	do { \
+		PriNode *ln; \
+		LIST_ASSERT_NOT_CONTAINS((list),(node)); \
+		FOREACH_NODE(ln, (list)) \
+			if (ln->pri < (node)->pri) \
+				break; \
+		INSERT_BEFORE(&(node)->link, &ln->link); \
+	} while (0)
+
+
+/**
+ * Unlink a node from the head of the list \a l.
+ *
+ * \return Pointer to node, or NULL if the list was empty.
+ */
+INLINE Node *list_remHead(List *l)
+{
+	Node *n;
+
+	ASSERT_VALID_PTR(l);
+
+	if (LIST_EMPTY(l))
+		return (Node *)0;
+
+	n = l->head.succ; /* Get first node. */
+	l->head.succ = n->succ; /* Link list head to second node. */
+	n->succ->pred = &l->head; /* Link second node to list head. */
+
+	INVALIDATE_NODE(n);
+	return n;
+}
+
+/**
+ * Unlink a node from the tail of the list \a l.
+ *
+ * \return Pointer to node, or NULL if the list was empty.
+ */
+INLINE Node *list_remTail(List *l)
+{
+	Node *n;
+
+	ASSERT_VALID_PTR(l);
+
+	if (LIST_EMPTY(l))
+		return NULL;
+
+	n = l->tail.pred; /* Get last node. */
+	l->tail.pred = n->pred; /* Link list tail to second last node. */
+	n->pred->succ = &l->tail; /* Link second last node to list tail. */
+
+	INVALIDATE_NODE(n);
+	return n;
+}
+
+/** \} */ //defgroup list
+
+#endif /* STRUCT_LIST_H */