add structure/LinkedList4

structure/LinkedList4.h

@@ -0,0 +1,246 @@
+/**
+ * @file LinkedList4.h
+ * @author Ambroz Bizjak <ambrop7@gmail.com>
+ * 
+ * @section LICENSE
+ * 
+ * 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 author 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 COPYRIGHT HOLDERS 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 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.
+ * 
+ * @section DESCRIPTION
+ * 
+ * Doubly linked list without a central object to represent the list.
+ * Like {@link LinkedList3}, but without iterators.
+ */
+
+#ifndef BADVPN_STRUCTURE_LINKEDLIST4_H
+#define BADVPN_STRUCTURE_LINKEDLIST4_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include <misc/debug.h>
+
+/**
+ * Linked list node.
+ */
+typedef struct _LinkedList4Node {
+    struct _LinkedList4Node *p;
+    struct _LinkedList4Node *n;
+} LinkedList4Node;
+
+/**
+ * Initializes a list node to form a new list consisting of a
+ * single node.
+ * 
+ * @param node list node structure to initialize. The node must remain
+ *        available until it is freed with {@link LinkedList4Node_Free},
+ *        or the list is no longer required.
+ */
+static void LinkedList4Node_InitLonely (LinkedList4Node *node);
+
+/**
+ * Initializes a list node to go after an existing node.
+ * 
+ * @param node list node structure to initialize. The node must remain
+ *        available until it is freed with {@link LinkedList4Node_Free},
+ *        or the list is no longer required.
+ * @param ref existing list node
+ */
+static void LinkedList4Node_InitAfter (LinkedList4Node *node, LinkedList4Node *ref);
+
+/**
+ * Initializes a list node to go before an existing node.
+ * 
+ * @param node list node structure to initialize. The node must remain
+ *        available until it is freed with {@link LinkedList4Node_Free},
+ *        or the list is no longer required.
+ * @param ref existing list node
+ */
+static void LinkedList4Node_InitBefore (LinkedList4Node *node, LinkedList4Node *ref);
+
+/**
+ * Frees a list node, removing it a list (if there were other nodes
+ * in the list).
+ * 
+ * @param node list node to free
+ */
+static void LinkedList4Node_Free (LinkedList4Node *node);
+
+/**
+ * Determines if a list node is a single node in a list.
+ * 
+ * @param node list node
+ * @return 1 if the node ia a single node, 0 if not
+ */
+static int LinkedList4Node_IsLonely (LinkedList4Node *node);
+
+/**
+ * Returnes the node preceding this node (if there is one),
+ * the node following this node (if there is one), or NULL,
+ * respectively.
+ * 
+ * @param node list node
+ * @return neighbour node or NULL if none
+ */
+static LinkedList4Node * LinkedList4Node_PrevOrNext (LinkedList4Node *node);
+
+/**
+ * Returnes the node following this node (if there is one),
+ * the node preceding this node (if there is one), or NULL,
+ * respectively.
+ * 
+ * @param node list node
+ * @return neighbour node or NULL if none
+ */
+static LinkedList4Node * LinkedList4Node_NextOrPrev (LinkedList4Node *node);
+
+/**
+ * Returns the node preceding this node, or NULL if there is none.
+ * 
+ * @param node list node
+ * @return left neighbour, or NULL if none
+ */
+static LinkedList4Node * LinkedList4Node_Prev (LinkedList4Node *node);
+
+/**
+ * Returns the node following this node, or NULL if there is none.
+ * 
+ * @param node list node
+ * @return right neighbour, or NULL if none
+ */
+static LinkedList4Node * LinkedList4Node_Next (LinkedList4Node *node);
+
+/**
+ * Returns the first node in the list which this node is part of.
+ * It is found by iterating the list from this node to the beginning.
+ * 
+ * @param node list node
+ * @return first node in the list
+ */
+static LinkedList4Node * LinkedList4Node_First (LinkedList4Node *node);
+
+/**
+ * Returns the last node in the list which this node is part of.
+ * It is found by iterating the list from this node to the end.
+ * 
+ * @param node list node
+ * @return last node in the list
+ */
+static LinkedList4Node * LinkedList4Node_Last (LinkedList4Node *node);
+
+void LinkedList4Node_InitLonely (LinkedList4Node *node)
+{
+    node->p = NULL;
+    node->n = NULL;
+}
+
+void LinkedList4Node_InitAfter (LinkedList4Node *node, LinkedList4Node *ref)
+{
+    ASSERT(ref)
+    
+    node->p = ref;
+    node->n = ref->n;
+    ref->n = node;
+    if (node->n) {
+        node->n->p = node;
+    }
+}
+
+void LinkedList4Node_InitBefore (LinkedList4Node *node, LinkedList4Node *ref)
+{
+    ASSERT(ref)
+    
+    node->n = ref;
+    node->p = ref->p;
+    ref->p = node;
+    if (node->p) {
+        node->p->n = node;
+    }
+}
+
+void LinkedList4Node_Free (LinkedList4Node *node)
+{
+    if (node->p) {
+        node->p->n = node->n;
+    }
+    if (node->n) {
+        node->n->p = node->p;
+    }
+}
+
+int LinkedList4Node_IsLonely (LinkedList4Node *node)
+{
+    return (!node->p && !node->n);
+}
+
+LinkedList4Node * LinkedList4Node_PrevOrNext (LinkedList4Node *node)
+{
+    if (node->p) {
+        return node->p;
+    }
+    if (node->n) {
+        return node->n;
+    }
+    return NULL;
+}
+
+LinkedList4Node * LinkedList4Node_NextOrPrev (LinkedList4Node *node)
+{
+    if (node->n) {
+        return node->n;
+    }
+    if (node->p) {
+        return node->p;
+    }
+    return NULL;
+}
+
+LinkedList4Node * LinkedList4Node_Prev (LinkedList4Node *node)
+{
+    return node->p;
+}
+
+LinkedList4Node * LinkedList4Node_Next (LinkedList4Node *node)
+{
+    return node->n;
+}
+
+LinkedList4Node * LinkedList4Node_First (LinkedList4Node *node)
+{
+    while (node->p) {
+        node = node->p;
+    }
+    
+    return node;
+}
+
+LinkedList4Node * LinkedList4Node_Last (LinkedList4Node *node)
+{
+    while (node->n) {
+        node = node->n;
+    }
+    
+    return node;
+}
+
+#endif