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Add common linked list functions 

Forms implemented to a greater or lesser degree at the moment:
ll_*   = singly-linked list
lld_*  = doubly-linked list
lldc_* = doubly-linked circular list

Change-Id: Ieed5af50fc59165c8b14c3513b3b5d0e6f7de9fa
This commit is contained in:
Michael Sevakis 2014-04-28 10:17:38 -04:00
parent 278e8664a7
commit eb63d8b4a2
3 changed files with 427 additions and 0 deletions
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1
firmware/SOURCES
View File

@ -172,6 +172,7 @@ common/dircache.c
#endif /* HAVE_DIRCACHE */
common/filefuncs.c
common/format.c
common/linked_list.c
#ifdef APPLICATION
common/rbpaths.c
#endif

312
firmware/common/linked_list.c Normal file
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@ -0,0 +1,312 @@
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2014 by Michael Sevakis
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include <stddef.h>
#include "linked_list.h"
/** (L)inked (L)ist **/
/**
* Helper to find the node previous to 'find'
*
* returns: NULL if 'find' is the first node
* last node if the 'find' isn't found in the list
*/
static struct ll_node * ll_search_prev(struct ll_head *list,
struct ll_node *find)
{
struct ll_node *prev = NULL;
struct ll_node *node = list->head;
while (node != NULL && node != find)
{
prev = node;
node = node->next;
}
return prev;
}
/**
* Initializes the singly-linked list
*/
void ll_init(struct ll_head *list)
{
list->head = NULL;
list->tail = NULL;
}
/**
* Adds a node to s singly-linked list using "insert next"
*/
void ll_insert_next(struct ll_head *list, struct ll_node *node,
struct ll_node *newnode)
{
if (node == NULL)
{
node = list->head;
newnode->next = node;
list->head = newnode;
if (node == NULL)
list->tail = node;
}
else
{
struct ll_node *next = node->next;
newnode->next = next;
node->next = newnode;
if (next == NULL)
list->tail = newnode;
}
}
/**
* Adds a node to a singly-linked list using "insert first"
*/
void ll_insert_first(struct ll_head *list, struct ll_node *node)
{
struct ll_node *head = list->head;
node->next = head;
list->head = node;
if (head == NULL)
list->tail = node;
}
/**
* Adds a node to a singly-linked list using "insert last"
*/
void ll_insert_last(struct ll_head *list, struct ll_node *node)
{
struct ll_node *tail = list->tail;
node->next = NULL;
list->tail = node;
if (tail == NULL)
list->head = node;
else
tail->next = node;
}
/**
* Removes the node after "node"; if there is none, nothing is changed
*/
void ll_remove_next(struct ll_head *list, struct ll_node *node)
{
if (node == NULL)
{
node = list->head->next;
list->head = node;
if (node == NULL)
list->tail = NULL;
}
else
{
struct ll_node *next = node->next;
if (next != NULL)
{
next = next->next;
node->next = next;
if (!next)
list->tail = node;
}
}
}
/**
* Removes the first node in the list
*/
void ll_remove_first(struct ll_head *list)
{
struct ll_node *node = list->head->next;
list->head = node;
if (node == NULL)
list->tail = NULL;
}
/**
* Removes the node from the list
*/
void ll_remove(struct ll_head *list, struct ll_node *node)
{
ll_remove_next(list, ll_search_prev(list, node));
}
/** (L)inked (L)ist (D)ouble **/
/**
* Initializes the doubly-linked list
*/
void lld_init(struct lld_head *list)
{
list->head = NULL;
list->tail = NULL;
/* tail could be stored in first item's prev pointer but this simplifies
the routines and maintains the non-circularity */
}
/**
* Adds a node to a doubly-linked list using "insert first"
*/
void lld_insert_first(struct lld_head *list, struct lld_node *node)
{
struct lld_node *head = list->head;
list->head = node;
if (head == NULL)
list->tail = node;
else
head->prev = node;
node->next = head;
node->prev = NULL;
}
/**
* Adds a node to a doubly-linked list using "insert last"
*/
void lld_insert_last(struct lld_head *list, struct lld_node *node)
{
struct lld_node *tail = list->tail;
list->tail = node;
if (tail == NULL)
list->head = node;
else
tail->next = node;
node->next = NULL;
node->prev = tail;
}
/**
* Removes a node from a doubly-linked list
*/
void lld_remove(struct lld_head *list, struct lld_node *node)
{
struct lld_node *next = node->next;
struct lld_node *prev = node->prev;
if (node == list->head)
list->head = next;
if (node == list->tail)
list->tail = prev;
if (prev != NULL)
prev->next = next;
if (next != NULL)
next->prev = prev;
}
/** (L)inked (L)ist (D)ouble (C)ircular **/
/**
* Helper that inserts a node into a doubly-link circular list; does not
* affect list->head, just returns its state
*/
static inline struct lldc_node * lldc_insert(struct lldc_head *list,
struct lldc_node *node)
{
struct lldc_node *head = list->head;
if (head == NULL)
{
node->prev = node;
node->next = node;
}
else
{
node->prev = head->prev;
node->next = head;
head->prev->next = node;
head->prev = node;
}
return head;
}
/**
* Initializes the doubly-linked circular list
*/
void lldc_init(struct lldc_head *list)
{
list->head = NULL;
}
/**
* Adds a node to a doubly-linked circular list using "insert first"
*/
void lldc_insert_first(struct lldc_head *list, struct lldc_node *node)
{
lldc_insert(list, node);
list->head = node;
}
/**
* Adds a node to a doubly-linked circular list using "insert last"
*/
void lldc_insert_last(struct lldc_head *list, struct lldc_node *node)
{
if (lldc_insert(list, node) == NULL)
list->head = node;
}
/**
* Removes a node from a doubly-linked circular list
*/
void lldc_remove(struct lldc_head *list, struct lldc_node *node)
{
struct lldc_node *next = node->next;
if (node == list->head)
{
if (node == next)
{
list->head = NULL;
return;
}
list->head = next;
}
struct lldc_node *prev = node->prev;
next->prev = prev;
prev->next = next;
}

114
firmware/include/linked_list.h Normal file
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@ -0,0 +1,114 @@
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2014 by Michael Sevakis
*
* 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 software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef LINKED_LIST_H
#define LINKED_LIST_H
/***
** NOTES:
** Node field order chosen so that one type can alias the other for forward
** list traveral by the same code.
**
** Structures are separate, even if logically equivalent, to perform compile-
** time type checking.
**
*/
/* (L)inked (L)ist
*
* Format:
*
* XX->YY->ZZ->0
* head--^ ^
* tail----------+
*/
struct ll_head
{
struct ll_node *head; /* First list item */
struct ll_node *tail; /* Last list item (to make insert_last O(1)) */
};
struct ll_node
{
struct ll_node *next; /* Next list item */
};
void ll_init(struct ll_head *list);
void ll_insert_next(struct ll_head *list, struct ll_node *node,
struct ll_node *newnode);
void ll_insert_last(struct ll_head *list, struct ll_node *node);
void ll_remove_next(struct ll_head *list, struct ll_node *node);
void ll_remove(struct ll_head *list, struct ll_node *node);
void ll_insert_first(struct ll_head *list, struct ll_node *node);
void ll_remove_first(struct ll_head *list);
/* (L)inked (L)ist (D)double
*
* Format:
*
* 0<-XX<->YY<->ZZ->0
* head----^ ^
* tail--------------+
*/
struct lld_head
{
struct lld_node *head; /* First list item */
struct lld_node *tail; /* Last list item (to make insert_last O(1)) */
};
struct lld_node
{
struct lld_node *next; /* Next list item */
struct lld_node *prev; /* Previous list item */
};
void lld_init(struct lld_head *list);
void lld_insert_first(struct lld_head *list, struct lld_node *node);
void lld_insert_last(struct lld_head *list, struct lld_node *node);
void lld_remove(struct lld_head *list, struct lld_node *node);
/* (L)inked (L)ist (D)ouble (C)ircular
*
* Format:
* +----------------+
* | |
* +->XX<->YY<->ZZ<-+
* head------^
*/
struct lldc_head
{
struct lldc_node *head; /* First list item */
};
struct lldc_node
{
struct lldc_node *next; /* Next list item */
struct lldc_node *prev; /* Previous list item */
};
void lldc_init(struct lldc_head *list);
void lldc_insert_first(struct lldc_head *list, struct lldc_node *node);
void lldc_insert_last(struct lldc_head *list, struct lldc_node *node);
void lldc_remove(struct lldc_head *list, struct lldc_node *node);
#endif /* LINKED_LIST_H */