bmv

Batch file moving utilities
git clone git://jacobedwards.org/bmv
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list.c (2873B)

      1 /*
      2  * Copyright (c) 2023 Jacob R. Edwards <jacob@jacobedwards.org>
      3  *
      4  * Permission to use, copy, modify, and distribute this software for any
      5  * purpose with or without fee is hereby granted, provided that the above
      6  * copyright notice and this permission notice appear in all copies.
      7  *
      8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
      9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     15  */
     16 
     17 #include <stdlib.h>
     18 
     19 #include "list.h"
     20 
     21 struct item *
     22 newitem(void *data)
     23 {
     24 	struct item *item;
     25 
     26 	item = calloc(1, sizeof(*item));
     27 	if (!item)
     28 		return NULL;
     29 
     30 	item->data = data;
     31 	return item;
     32 }
     33 
     34 void
     35 freeitem(struct item *item)
     36 {
     37 	free(item);
     38 }
     39 
     40 struct list *
     41 newlist(void (*freedata)(void *))
     42 {
     43 	struct list *list;
     44 
     45 	list = calloc(1, sizeof(*list));
     46 	if (!list)
     47 		return NULL;
     48 
     49 	list->freedata = freedata;
     50 	return list;
     51 }
     52 
     53 void
     54 freelist(struct list *list)
     55 {
     56 	struct item *item, *nextitem;
     57 
     58 	if (!list)
     59 		return;
     60 
     61 	for (item = list->items; item; item = nextitem) {
     62 		nextitem = item->next;
     63 		if (list->freedata)
     64 			list->freedata(item->data);
     65 		freeitem(item);
     66 	}
     67 	free(list);
     68 }
     69 
     70 /*
     71  * The linkitem and unlinkitem functions are provided so that you
     72  * may choose not to use the list struct. Unfortunatly I couldn't
     73  * think of sane names which tell of this difference from the add
     74  * and remove item functions.
     75  */
     76 void
     77 linkitem(struct item *item, struct item *to)
     78 {
     79 	/* This function could check
     80 	 * 	if (item->next || item->prev)
     81 	 * and
     82 	 * 	abort();
     83 	 * or return an error, but it does not. Maybe it should?
     84 	 */
     85 
     86 	item->next = to->next;
     87 	if (item->next)
     88 		item->next->prev = item;
     89 	item->prev = to;
     90 	if (to)
     91 		to->next = item;
     92 }
     93 
     94 void
     95 unlinkitem(struct item *item)
     96 {
     97 	if (item->next)
     98 		item->next->prev = item->prev;
     99 	if (item->prev)
    100 		item->prev->next = item->next;
    101 	item->next = item->prev = NULL;
    102 }
    103 
    104 void
    105 additem(struct item *item, struct list *list, struct item *pos)
    106 {
    107 	if (pos) {
    108 		linkitem(item, pos);
    109 		if (pos == list->last)
    110 			list->last = item;
    111 	} else {
    112 		if (!list->items)
    113 			list->last = item;
    114 		item->prev = NULL;
    115 		item->next = list->items;
    116 		if (item->next)
    117 			item->next->prev = item;
    118 		list->items = item;
    119 	}
    120 }
    121 
    122 void
    123 removeitem(struct item *item, struct list *list)
    124 {
    125 	if (item == list->items)
    126 		list->items = item->next;
    127 	if (item == list->last)
    128 		list->last = item->prev;
    129 	unlinkitem(item);
    130 }
    131 
    132 void
    133 deleteitem(struct item *item, struct list *list)
    134 {
    135 	removeitem(item, list);
    136 	if (list->freedata)
    137 		list->freedata(item->data);
    138 	freeitem(item);
    139 }