121 lines
2.8 KiB
C
121 lines
2.8 KiB
C
/*
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* safe_list - linked list protected against recursive iteration with deletes
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*
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* Copyright (C) 2013 Felix Fietkau <nbd@openwrt.org>
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include "safe_list.h"
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struct safe_list_iterator {
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struct safe_list_iterator **head;
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struct safe_list_iterator *next_i;
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struct safe_list *next;
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};
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static void
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__safe_list_set_iterator(struct safe_list *list,
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struct safe_list_iterator *i)
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{
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struct safe_list_iterator *next_i;
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struct safe_list *next;
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next = list_entry(list->list.next, struct safe_list, list);
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next_i = next->i;
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next->i = i;
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i->next = next;
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i->head = &next->i;
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i->next_i = next_i;
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if (next_i)
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next_i->head = &i->next_i;
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}
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static void
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__safe_list_del_iterator(struct safe_list_iterator *i)
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{
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*i->head = i->next_i;
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if (i->next_i)
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i->next_i->head = i->head;
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}
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static void
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__safe_list_move_iterator(struct safe_list *list,
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struct safe_list_iterator *i)
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{
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__safe_list_del_iterator(i);
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__safe_list_set_iterator(list, i);
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}
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int safe_list_for_each(struct safe_list *head,
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int (*cb)(void *ctx, struct safe_list *list),
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void *ctx)
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{
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struct safe_list_iterator i;
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struct safe_list *cur;
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int ret = 0;
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for (cur = list_entry(head->list.next, struct safe_list, list),
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__safe_list_set_iterator(cur, &i);
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cur != head;
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cur = i.next, __safe_list_move_iterator(cur, &i)) {
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ret = cb(ctx, cur);
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if (ret)
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break;
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}
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__safe_list_del_iterator(&i);
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return ret;
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}
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void safe_list_add(struct safe_list *list, struct safe_list *head)
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{
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list->i = NULL;
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list_add_tail(&list->list, &head->list);
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}
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void safe_list_add_first(struct safe_list *list, struct safe_list *head)
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{
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list->i = NULL;
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list_add(&list->list, &head->list);
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}
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void safe_list_del(struct safe_list *list)
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{
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struct safe_list_iterator *i, *next_i, **tail;
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struct safe_list *next;
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next = list_entry(list->list.next, struct safe_list, list);
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list_del(&list->list);
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if (!list->i)
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return;
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next_i = next->i;
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tail = &next->i;
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for (i = list->i; i; i = i->next_i) {
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tail = &i->next_i;
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i->next = next;
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}
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next->i = list->i;
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list->i->head = &next->i;
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*tail = next_i;
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if (next_i)
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next_i->head = tail;
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list->i = NULL;
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}
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