diff options
Diffstat (limited to 'libsysfs/dlist.c')
| -rw-r--r-- | libsysfs/dlist.c | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/libsysfs/dlist.c b/libsysfs/dlist.c new file mode 100644 index 0000000000..6dfcf726ba --- /dev/null +++ b/libsysfs/dlist.c @@ -0,0 +1,343 @@ +/* + * 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 "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->next!=NULL) + list->marker=list->marker->next; + else + return(NULL); + } + else + { + if( 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); +} + +/* + * 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); +} + + +/* + * 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); +} + + +/* + * 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)); +} |