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systemd/libsysfs/dlist.c
kay.sievers@vrfy.org 197178360f [PATCH] libsysfs: version 2.0
2005-04-26 23:55:01 -07:00

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/*
* dlist.c
*
* Copyright (C) 2003 Eric J Bohm
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 021110307 USA
*
*/
/* Double linked list implementation.
* You allocate the data and give dlist the pointer.
* If your data is complex set the dlist->del_func to a an appropriate
* delete function. Otherwise dlist will just use free.
*/
#include "stdlib.h"
#include "dlist.h"
/*
* Return pointer to node at marker.
* else null if no nodes.
*/
inline void *dlist_mark(Dlist *list)
{
if(list->marker!=NULL)
return(list->marker->data);
else
return(NULL);
}
/*
* Set marker to start.
*/
inline void dlist_start(Dlist *list)
{
list->marker=list->head;
}
/*
* Set marker to end.
*/
inline void dlist_end(Dlist *list)
{
list->marker=list->head;
}
/* internal use function
* quickie inline to consolidate the marker movement logic
* in one place
*
* when direction true it moves marker after
* when direction false it moves marker before.
* return pointer to data at new marker
* if nowhere to move the marker in desired direction return null
*/
inline void *_dlist_mark_move(Dlist *list,int direction)
{
if(direction)
{
if( list->marker && list->marker->next!=NULL)
list->marker=list->marker->next;
else
return(NULL);
}
else
{
if( list->marker && list->marker->prev!=NULL)
list->marker=list->marker->prev;
else
return(NULL);
}
if(list->marker!=list->head)
return(list->marker->data);
else
return(NULL);
}
/*
* Create new linked list to store nodes of datasize.
* return null if list cannot be created.
*/
Dlist *dlist_new(size_t datasize)
{
Dlist *list=NULL;
if((list=malloc(sizeof(Dlist))))
{
list->marker=NULL;
list->count=0L;
list->data_size=datasize;
list->del_func=free;
list->head=&(list->headnode);
list->head->prev=NULL;
list->head->next=NULL;
list->head->data=NULL;
}
return(list);
}
/*
* Create new linked list to store nodes of datasize set list
* data node delete function to the passed in del_func
* return null if list cannot be created.
*/
Dlist *dlist_new_with_delete(size_t datasize,void (*del_func)(void*))
{
Dlist *list=NULL;
list=dlist_new(datasize);
if(list!=NULL)
list->del_func=del_func;
return(list);
}
/*
* remove marker node from list
* call data_delete function on data if registered.
* otherwise call free.
* when direction true it moves marker after
* when direction false it moves marker before.
* free marker node
* return nothing.
*/
void dlist_delete(Dlist *list,int direction)
{
if((list->marker != list->head)&&(list->marker!=NULL))
{
DL_node *corpse;
corpse=list->marker;
_dlist_mark_move(list,direction);
if(list->head->next==corpse)
list->head->next=corpse->next;
if(list->head->prev==corpse)
list->head->prev=corpse->prev;
if(corpse->prev!=NULL) //should be impossible
corpse->prev->next=corpse->next;
if(corpse->next!=NULL) //should be impossible
corpse->next->prev=corpse->prev;
list->del_func(corpse->data);
list->count--;
free(corpse);
}
}
/*
* Insert node containing data at marker.
* If direction true it inserts after.
* If direction false it inserts before.
* move marker to inserted node
* return pointer to inserted node
*/
void *dlist_insert(Dlist *list,void *data,int direction)
{
DL_node *new_node=NULL;
if(list==NULL || data==NULL)
return(NULL);
if(list->marker==NULL) //in case the marker ends up unset
list->marker=list->head;
if((new_node=malloc(sizeof(DL_node))))
{
new_node->data=data;
new_node->prev=NULL;
new_node->next=NULL;
list->count++;
if(list->head->next==NULL) //no l
{
list->head->next=list->head->prev=new_node;
new_node->prev=list->head;
new_node->next=list->head;
}
else if(direction)
{
new_node->next=list->marker->next;
new_node->prev=list->marker;
list->marker->next->prev=new_node;
list->marker->next=new_node;
}
else
{
new_node->prev=list->marker->prev;
new_node->next=list->marker;
list->marker->prev->next=new_node;
list->marker->prev=new_node;
}
list->marker=new_node;
}
else
{
return(NULL);
}
return(list->marker->data);
}
/* internal use only
* Insert dl_node at marker.
* If direction true it inserts after.
* If direction false it inserts before.
* move marker to inserted node
* return pointer to inserted node
*/
void *_dlist_insert_dlnode(struct dlist *list,struct dl_node *new_node,int direction)
{
if(list==NULL || new_node==NULL)
return(NULL);
if(list->marker==NULL) //in case the marker ends up unset
list->marker=list->head;
list->count++;
if(list->head->next==NULL)
{
list->head->next=list->head->prev=new_node;
new_node->prev=list->head;
new_node->next=list->head;
}
else if(direction)
{
new_node->next=list->marker->next;
new_node->prev=list->marker;
list->marker->next->prev=new_node;
list->marker->next=new_node;
}
else
{
new_node->prev=list->marker->prev;
new_node->next=list->marker;
list->marker->prev->next=new_node;
list->marker->prev=new_node;
}
list->marker=new_node;
return(list->marker);
}
/*
* Remove DL_node from list without deallocating data.
* if marker == killme .
* when direction true it moves marker after
* when direction false it moves marker before.
* to previous if there is no next.
*/
void *_dlist_remove(Dlist *list,DL_node *killme,int direction)
{
if(killme!=NULL)
{
void *killer_data=killme->data;
// take care of head and marker pointers.
if(list->marker==killme)
_dlist_mark_move(list,direction);
if(killme ==list->head->next)
list->head->next=killme->next;
if(killme==list->head->prev)
list->head->prev=killme->prev;
// remove from list
if(killme->prev !=NULL)
killme->prev->next=killme->next;
if(killme->next !=NULL)
killme->next->prev=killme->prev;
list->count--;
free(killme);
return(killer_data);
}
else
return (NULL);
}
/*
* move dl_node from source to dest
* if marker == target .
* when direction true it moves marker after
* when direction false it moves marker before.
* to previous if there is no next.
*/
void dlist_move(struct dlist *source, struct dlist *dest, struct dl_node *target,int direction)
{
if(target!=NULL)
{
if(target==source->head)
{
//not even going to try
}
else
{
// take care of head and marker pointers.
if(source->marker==target)
_dlist_mark_move(source,direction);
if(target ==source->head->next)
source->head->next=target->next;
if(target==source->head->prev)
source->head->prev=target->prev;
// remove from list
if(source->count==1)
{
target->prev=NULL;
target->next=NULL;
source->head->next=NULL;
source->head->prev=NULL;
}
else
{
if(target->prev !=NULL)
target->prev->next=target->next;
if(target->next !=NULL)
target->next->prev=target->prev;
target->prev=NULL;
target->next=NULL;
}
source->count--;
_dlist_insert_dlnode(dest,target,direction);
}
}
}
/*
* Insert node containing data after end.
*/
void dlist_push(Dlist *list,void *data)
{
list->marker=list->head->prev;
dlist_insert(list,data,1);
}
/*
* Insert node containing data at start.
*/
void dlist_unshift(Dlist *list,void *data)
{
list->marker=list->head->next;
dlist_insert(list,data,0);
}
void dlist_unshift_sorted(Dlist *list, void *data,
int (*sorter)(void *new_elem, void *old_elem))
{
if (list->count == 0)
dlist_unshift(list, data);
else {
list->marker=list->head->next;
dlist_insert_sorted(list, data, sorter);
}
}
/*
* Remove end node from list.
* Return pointer to data in removed node.
* Null if no nodes.
*/
void *dlist_pop(Dlist *list)
{
return(_dlist_remove(list,list->head->prev,0));
}
/*
* Remove start node from list.
* Return pointer to data in removed node.
* Null if no nodes.
*/
void *dlist_shift(Dlist *list)
{
return(_dlist_remove(list,list->head->next,1));
}
/*
* destroy the list freeing all memory
*/
void dlist_destroy(Dlist *list)
{
if(list !=NULL)
{
dlist_start(list);
dlist_next(list);
while (dlist_mark(list)) {
dlist_delete(list,1);
}
free(list);
}
}
/**
* Return void pointer to list_data element matching comp function criteria
* else null
* Does not move the marker.
*/
void *dlist_find_custom(struct dlist *list, void *target, int (*comp)(void *, void *))
{
/* test the comp function on each node */
struct dl_node *nodepointer;
dlist_for_each_nomark(list,nodepointer)
if(comp(target,nodepointer->data))
return(nodepointer->data);
return(NULL);
}
/**
* Apply the node_operation function to each data node in the list
*/
void dlist_transform(struct dlist *list, void (*node_operation)(void *))
{
struct dl_node *nodepointer;
dlist_for_each_nomark(list,nodepointer)
node_operation(nodepointer->data);
}
/**
* insert new into list in sorted order
* sorter function in form int sorter(new,ith)
* must return 1 for when new should go before ith
* else 0
* return pointer to inserted node
* NOTE: assumes list is already sorted
*/
void *dlist_insert_sorted(struct dlist *list, void *new, int (*sorter)(void *, void *))
{
for(dlist_start(list),dlist_next(list); \
list->marker!=list->head && !sorter(new,list->marker->data);dlist_next(list));
return(dlist_insert_before(list,new));
}
/*
* NOTE: internal use only
*/
int _dlist_merge(struct dlist *listsource, struct dlist *listdest, unsigned int passcount, int (*compare)(void *, void *))
{
struct dl_node *l1head;
struct dl_node *l2head;
struct dl_node *target;
unsigned int l1count=0;
unsigned int l2count=0;
unsigned int mergecount=0;
while(listsource->count>0)
{
l1head=listsource->head->next;
l2head=l1head;
while((l1count<passcount)&&(l2head!=listsource->head))
{
l2head=l2head->next;
l1count++;
}
// so now we have two lists to merge
if(l2head==listsource->head)
{// l2count
l2count=0;
}
else
{
l2count=passcount;
}
while(l1count>0 || l2count>0)
{
mergecount++;
if((l2count>0)&&(l1count>0))
{
// we have things to merge
int result=compare(l1head->data,l2head->data);
if(result>0)
{
// move from l2
target=l2head;
l2head=l2head->next;
dlist_move(listsource,listdest,target,1);
l2count--;
if(l2head==listsource->head)
l2count=0;
}
else
{
// move from l1
target=l1head;
l1head=l1head->next;
dlist_move(listsource,listdest,target,1);
l1count--;
}
}
else if(l1count>0)
{
// only have l1 to work with
while(l1count>0)
{
target=l1head;
l1head=l1head->next;
dlist_move(listsource,listdest,target,1);
l1count--;
}
}
else if(l2count>0)
{
// only have l2 to work with
while(l2count>0)
{
if(l2head==listsource->head)
{
l2count=0;
}
else
{
target=l2head;
l2head=l2head->next;
dlist_move(listsource,listdest,target,1);
l2count--;
}
}
}
else
{ //nothing left and this should be unreachable
}
}
}
return(mergecount);
}
/**
* mergesort the list based on compare
* compare function in form int sorter(void * a,void * b)
* must return >0 for a after b
* must return <0 for a before b
* else 0
* NOTE: mergesort changes the mark pointer
*/
void dlist_sort_custom(struct dlist *list, int (*compare)(void *, void *))
{
struct dlist *listsource, *listdest, *swap;
struct dlist *templist;
unsigned int passcount = 1;
unsigned int mergecount = 1;
dlist_start(list);
templist = dlist_new(list->data_size);
// do nothing if there isn't anything to sort
listsource = list;
listdest = templist;
if(listsource->count<2)
{ //nothing to do
return;
}
else
{
while(mergecount>0)
{
mergecount=_dlist_merge(listsource, listdest, passcount, compare);
if(mergecount>1)
{
passcount=passcount*2;
//start new pass
swap=listsource;
listsource=listdest;
listdest=swap;
}
}
}
// now put the input list pointers right
// list pointers = newlist pointers
// including the forward and next nodes prev and back pointers
if(list->count==0)
{//copy
list->marker = listdest->marker;
list->count = listdest->count;
list->data_size = listdest->data_size;
list->del_func = listdest->del_func;
list->head->prev = listdest->head->prev;
list->head->next = listdest->head->next;
list->head->data = listdest->head->data;
list->head->next->prev=list->head;
list->head->prev->next=list->head;
templist->head->next=NULL;
templist->head->prev=NULL;
templist->count=0;
}
else
{// no need to copy
}
dlist_destroy(templist);
}
/* internal use function
swaps elements a and b
No sense in juggling node pointers when we can just swap the data pointers
*/
void _dlist_swap(struct dlist *list, struct dl_node *a, struct dl_node *b)
{
void *swap=a->data;
a->data=b->data;
b->data=swap;
}
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