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Add circular, doubly-linked list library

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George Oikonomou 2017-12-10 23:12:07 +00:00
parent 09d6b123ab
commit e87e3850c4
2 changed files with 420 additions and 0 deletions
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os/lib/dbl-circ-list.c Normal file
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/*
* Copyright (c) 2017, George Oikonomou - http://www.spd.gr
* Copyright (c) 2017, James Pope
* 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 copyright holder 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
* COPYRIGHT HOLDER 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.
*/
/*---------------------------------------------------------------------------*/
/**
* \addtogroup doubly-linked-circular-list
* @{
*
* \file
* Implementation of circular, doubly-linked lists
*/
/*---------------------------------------------------------------------------*/
#include "contiki.h"
#include "lib/dbl-circ-list.h"
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
/*---------------------------------------------------------------------------*/
struct dblcl {
struct dblcl *next;
struct dblcl *previous;
};
/*---------------------------------------------------------------------------*/
void
dbl_circ_list_init(dbl_circ_list_t dblcl)
{
*dblcl = NULL;
}
/*---------------------------------------------------------------------------*/
void *
dbl_circ_list_head(dbl_circ_list_t dblcl)
{
return *dblcl;
}
/*---------------------------------------------------------------------------*/
void *
dbl_circ_list_tail(dbl_circ_list_t dblcl)
{
struct dblcl *this;
if(*dblcl == NULL) {
return NULL;
}
for(this = *dblcl; this->next != *dblcl; this = this->next);
return this;
}
/*---------------------------------------------------------------------------*/
void
dbl_circ_list_remove(dbl_circ_list_t dblcl, void *element)
{
struct dblcl *this;
if(*dblcl == NULL || element == NULL) {
return;
}
this = *dblcl;
do {
if(this == element) {
this->previous->next = this->next;
this->next->previous = this->previous;
/* We need to update the head of the list if we removed the head */
if(*dblcl == element) {
*dblcl = this->next == this ? NULL : this->next;
}
this->next = NULL;
this->previous = NULL;
return;
}
this = this->next;
} while(this != *dblcl);
}
/*---------------------------------------------------------------------------*/
void
dbl_circ_list_add_head(dbl_circ_list_t dblcl, void *element)
{
struct dblcl *head;
if(element == NULL) {
return;
}
/* Don't add twice */
dbl_circ_list_remove(dblcl, element);
head = dbl_circ_list_head(dblcl);
if(head == NULL) {
/* If the list was empty */
((struct dblcl *)element)->next = element;
((struct dblcl *)element)->previous = element;
} else {
/* If the list was not empty */
((struct dblcl *)element)->next = head;
((struct dblcl *)element)->previous = head->previous;
head->previous->next = element;
head->previous = element;
}
*dblcl = element;
}
/*---------------------------------------------------------------------------*/
void
dbl_circ_list_add_tail(dbl_circ_list_t dblcl, void *element)
{
struct dblcl *tail;
if(element == NULL) {
return;
}
/* Don't add twice */
dbl_circ_list_remove(dblcl, element);
tail = dbl_circ_list_tail(dblcl);
if(tail == NULL) {
/* If the list was empty */
((struct dblcl *)element)->next = element;
((struct dblcl *)element)->previous = element;
*dblcl = element;
} else {
/* If the list was not empty */
((struct dblcl *)element)->next = *dblcl;
((struct dblcl *)element)->previous = tail;
tail->next->previous = element;
tail->next = element;
}
}
/*---------------------------------------------------------------------------*/
void
dbl_circ_list_add_after(dbl_circ_list_t dblcl, void *existing, void *element)
{
if(element == NULL || existing == NULL) {
return;
}
/* Don't add twice */
dbl_circ_list_remove(dblcl, element);
((struct dblcl *)element)->next = ((struct dblcl *)existing)->next;
((struct dblcl *)element)->previous = existing;
((struct dblcl *)existing)->next->previous = element;
((struct dblcl *)existing)->next = element;
}
/*---------------------------------------------------------------------------*/
void
dbl_circ_list_add_before(dbl_circ_list_t dblcl, void *existing, void *element)
{
if(element == NULL || existing == NULL) {
return;
}
/* Don't add twice */
dbl_circ_list_remove(dblcl, element);
((struct dblcl *)element)->next = existing;
((struct dblcl *)element)->previous = ((struct dblcl *)existing)->previous;
((struct dblcl *)existing)->previous->next = element;
((struct dblcl *)existing)->previous = element;
/* If we added before the list's head, we must update the head */
if(*dblcl == existing) {
*dblcl = element;
}
}
/*---------------------------------------------------------------------------*/
unsigned long
dbl_circ_list_length(dbl_circ_list_t dblcl)
{
unsigned long len = 1;
struct dblcl *this;
if(*dblcl == NULL) {
return 0;
}
for(this = *dblcl; this->next != *dblcl; this = this->next) {
len++;
}
return len;
}
/*---------------------------------------------------------------------------*/
bool
dbl_circ_list_is_empty(dbl_circ_list_t dblcl)
{
return *dblcl == NULL ? true : false;
}
/*---------------------------------------------------------------------------*/
/** @} */

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/*
* Copyright (c) 2017, George Oikonomou - http://www.spd.gr
* Copyright (c) 2017, James Pope
* 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 copyright holder 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
* COPYRIGHT HOLDER 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.
*/
/*---------------------------------------------------------------------------*/
/** \addtogroup data
* @{
*
* \defgroup doubly-linked-circular-list Circular, doubly-linked list
*
* This library provides functions for the creation and manipulation of
* circular, doubly-linked lists.
*
* A circular, doubly-linked list is declared using the DBL_CIRC_LIST macro.
* Elements must be allocated by the calling code and must be of a C struct
* datatype. In this struct, the first field must be a pointer called \e next.
* The second field must be a pointer called \e previous.
* These fields will be used by the library to maintain the list. Application
* code must not modify these fields directly.
*
* Functions that modify the list (add / remove) will, in the general case,
* update the list's head and item order. If you call one of these functions
* as part of a list traversal, it is advised to stop / restart traversing
* after the respective function returns.
* @{
*/
/*---------------------------------------------------------------------------*/
#ifndef DBL_CIRC_LIST_H_
#define DBL_CIRC_LIST_H_
/*---------------------------------------------------------------------------*/
#include "contiki.h"
#include <stdint.h>
#include <stdbool.h>
#include <string.h>
/*---------------------------------------------------------------------------*/
/**
* \brief Define a circular, doubly-linked list.
*
* This macro defines a circular, doubly-linked list.
*
* The datatype for elements must be a C struct.
* The struct's first member must be a pointer called \e next.
* The second field must be a pointer called \e previous.
* These fields will be used by the library to maintain the list. Application
* code must not modify these fields directly.
*
* \param name The name of the circular, doubly-linked list.
*/
#define DBL_CIRC_LIST(name) \
static void *name##_dbl_circ_list = NULL; \
static dbl_list_t name = (dbl_circ_list_t)&name##_dbl_circ_list
/*---------------------------------------------------------------------------*/
/**
* \brief The doubly-linked list datatype
*/
typedef void **dbl_circ_list_t;
/*---------------------------------------------------------------------------*/
/**
* \brief Initialise a circular, doubly-linked list.
* \param dblcl The circular, doubly-linked list.
*/
void dbl_circ_list_init(dbl_circ_list_t dblcl);
/**
* \brief Return the tail of a circular, doubly-linked list.
* \param dblcl The circular, doubly-linked list.
* \return A pointer to the list's head, or NULL if the list is empty
*/
void *dbl_circ_list_head(dbl_circ_list_t dblcl);
/**
* \brief Return the tail of a circular, doubly-linked list.
* \param dblcl The circular, doubly-linked list.
* \return A pointer to the list's tail, or NULL if the list is empty
*/
void *dbl_circ_list_tail(dbl_circ_list_t dblcl);
/**
* \brief Add an element to the head of a circular, doubly-linked list.
* \param dblcl The circular, doubly-linked list.
* \param element A pointer to the element to be added.
*
* Calling this function will update the list's head and item order. If you
* call this function as part of a list traversal, it is advised to stop
* traversing after this function returns.
*/
void dbl_circ_list_add_head(dbl_circ_list_t dblcl, void *element);
/**
* \brief Add an element to the tail of a circular, doubly-linked list.
* \param dblcl The circular, doubly-linked list.
* \param element A pointer to the element to be added.
*
* Calling this function will update the list's head and item order. If you
* call this function as part of a list traversal, it is advised to stop
* traversing after this function returns.
*/
void dbl_circ_list_add_tail(dbl_circ_list_t dblcl, void *element);
/**
* \brief Add an element to a circular, doubly linked list after an existing element.
* \param dblcl The circular, doubly-linked list.
* \param existing A pointer to the existing element.
* \param element A pointer to the element to be added.
*
* This function will add \e element after \e existing
*
* The function will not verify that \e existing is already part of the list.
*
* Calling this function will update the list's head and item order. If you
* call this function as part of a list traversal, it is advised to stop
* traversing after this function returns.
*/
void dbl_circ_list_add_after(dbl_circ_list_t dblcl, void *existing,
void *element);
/**
* \brief Add an element to a circular, doubly linked list before an existing element.
* \param dblcl The circular, doubly-linked list.
* \param existing A pointer to the existing element.
* \param element A pointer to the element to be added.
*
* This function will add \e element before \e existing
*
* The function will not verify that \e existing is already part of the list.
*
* Calling this function will update the list's head and item order. If you
* call this function as part of a list traversal, it is advised to stop
* traversing after this function returns.
*/
void dbl_circ_list_add_before(dbl_circ_list_t dblcl, void *existing,
void *element);
/**
* \brief Remove an element from a circular, doubly-linked list.
* \param dblcl The circular, doubly-linked list.
* \param element A pointer to the element to be removed.
*
* Calling this function will update the list's head and item order. If you
* call this function as part of a list traversal, it is advised to stop
* traversing after this function returns.
*/
void dbl_circ_list_remove(dbl_circ_list_t dblcl, void *element);
/**
* \brief Get the length of a circular, doubly-linked list.
* \param dblcl The circular, doubly-linked list.
* \return The number of elements in the list
*/
unsigned long dbl_circ_list_length(dbl_circ_list_t dblcl);
/**
* \brief Determine whether a circular, doubly-linked list is empty.
* \param dblcl The circular, doubly-linked list.
* \retval true The list is empty
* \retval false The list is not empty
*/
bool dbl_circ_list_is_empty(dbl_circ_list_t dblcl);
/*---------------------------------------------------------------------------*/
#endif /* DBL_CIRC_LIST_H_ */
/*---------------------------------------------------------------------------*/
/**
* @}
* @}
*/