BadVPN – Rev 1
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/**
* @file LinkedList3.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 that support multiple iterations and removing
* aritrary elements during iteration, without a central object to
* represent the list.
*/
#ifndef BADVPN_STRUCTURE_LINKEDLIST3_H
#define BADVPN_STRUCTURE_LINKEDLIST3_H
#include <stddef.h>
#include <stdint.h>
#include <misc/debug.h>
struct _LinkedList3Iterator;
/**
* Linked list node.
*/
typedef struct _LinkedList3Node {
struct _LinkedList3Node *p;
struct _LinkedList3Node *n;
struct _LinkedList3Iterator *it;
} LinkedList3Node;
/**
* Linked list iterator.
*/
typedef struct _LinkedList3Iterator {
int8_t dir;
struct _LinkedList3Node *e;
struct _LinkedList3Iterator *pi;
struct _LinkedList3Iterator *ni;
} LinkedList3Iterator;
/**
* 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 LinkedList3Node_Free},
* or the list is no longer required.
*/
static void LinkedList3Node_InitLonely (LinkedList3Node *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 LinkedList3Node_Free},
* or the list is no longer required.
* @param ref existing list node
*/
static void LinkedList3Node_InitAfter (LinkedList3Node *node, LinkedList3Node *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 LinkedList3Node_Free},
* or the list is no longer required.
* @param ref existing list node
*/
static void LinkedList3Node_InitBefore (LinkedList3Node *node, LinkedList3Node *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 LinkedList3Node_Free (LinkedList3Node *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 LinkedList3Node_IsLonely (LinkedList3Node *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 LinkedList3Node * LinkedList3Node_PrevOrNext (LinkedList3Node *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 LinkedList3Node * LinkedList3Node_NextOrPrev (LinkedList3Node *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 LinkedList3Node * LinkedList3Node_Prev (LinkedList3Node *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 LinkedList3Node * LinkedList3Node_Next (LinkedList3Node *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 LinkedList3Node * LinkedList3Node_First (LinkedList3Node *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 LinkedList3Node * LinkedList3Node_Last (LinkedList3Node *node);
/**
* Initializes a linked list iterator.
* The iterator structure must remain available until either of these occurs:
* - the list is no longer needed, or
* - the iterator is freed with {@link LinkedList3Iterator_Free}, or
* - the iterator reaches the end of iteration.
*
* @param it uninitialized iterator to initialize
* @param e initial position of the iterator. NULL for end of iteration.
* @param dir direction of iteration. Must be 1 (forward) or -1 (backward).
*/
static void LinkedList3Iterator_Init (LinkedList3Iterator *it, LinkedList3Node *e, int dir);
/**
* Frees a linked list iterator.
*
* @param it iterator to free
*/
static void LinkedList3Iterator_Free (LinkedList3Iterator *it);
/**
* Moves the iterator one node forward or backward (depending on its direction), or,
* if it's at the last or first node (depending on the direction), it reaches
* the end of iteration, or, if it's at the end of iteration, it remains there.
* Returns the the previous position.
*
* @param it the iterator
* @return node on the position of iterator before it was (possibly) moved, or NULL
* if it was at the end of iteration
*/
static LinkedList3Node * LinkedList3Iterator_Next (LinkedList3Iterator *it);
void LinkedList3Node_InitLonely (LinkedList3Node *node)
{
node->p = NULL;
node->n = NULL;
node->it = NULL;
}
void LinkedList3Node_InitAfter (LinkedList3Node *node, LinkedList3Node *ref)
{
ASSERT(ref)
node->p = ref;
node->n = ref->n;
ref->n = node;
if (node->n) {
node->n->p = node;
}
node->it = NULL;
}
void LinkedList3Node_InitBefore (LinkedList3Node *node, LinkedList3Node *ref)
{
ASSERT(ref)
node->n = ref;
node->p = ref->p;
ref->p = node;
if (node->p) {
node->p->n = node;
}
node->it = NULL;
}
void LinkedList3Node_Free (LinkedList3Node *node)
{
// jump iterators
while (node->it) {
LinkedList3Iterator_Next(node->it);
}
if (node->p) {
node->p->n = node->n;
}
if (node->n) {
node->n->p = node->p;
}
}
int LinkedList3Node_IsLonely (LinkedList3Node *node)
{
return (!node->p && !node->n);
}
LinkedList3Node * LinkedList3Node_PrevOrNext (LinkedList3Node *node)
{
if (node->p) {
return node->p;
}
if (node->n) {
return node->n;
}
return NULL;
}
LinkedList3Node * LinkedList3Node_NextOrPrev (LinkedList3Node *node)
{
if (node->n) {
return node->n;
}
if (node->p) {
return node->p;
}
return NULL;
}
LinkedList3Node * LinkedList3Node_Prev (LinkedList3Node *node)
{
return node->p;
}
LinkedList3Node * LinkedList3Node_Next (LinkedList3Node *node)
{
return node->n;
}
LinkedList3Node * LinkedList3Node_First (LinkedList3Node *node)
{
while (node->p) {
node = node->p;
}
return node;
}
LinkedList3Node * LinkedList3Node_Last (LinkedList3Node *node)
{
while (node->n) {
node = node->n;
}
return node;
}
void LinkedList3Iterator_Init (LinkedList3Iterator *it, LinkedList3Node *e, int dir)
{
ASSERT(dir == -1 || dir == 1)
it->dir = dir;
it->e = e;
if (e) {
// link into node's iterator list
it->pi = NULL;
it->ni = e->it;
if (e->it) {
e->it->pi = it;
}
e->it = it;
}
}
void LinkedList3Iterator_Free (LinkedList3Iterator *it)
{
if (it->e) {
// remove from node's iterator list
if (it->ni) {
it->ni->pi = it->pi;
}
if (it->pi) {
it->pi->ni = it->ni;
} else {
it->e->it = it->ni;
}
}
}
LinkedList3Node * LinkedList3Iterator_Next (LinkedList3Iterator *it)
{
// remember original entry
LinkedList3Node *orig = it->e;
// jump to next entry
if (it->e) {
// get next entry
LinkedList3Node *next = NULL; // to remove warning
switch (it->dir) {
case 1:
next = it->e->n;
break;
case -1:
next = it->e->p;
break;
default:
ASSERT(0);
}
// destroy interator
LinkedList3Iterator_Free(it);
// re-initialize at next entry
LinkedList3Iterator_Init(it, next, it->dir);
}
// return original entry
return orig;
}
#endif