//
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// Copyright 2017 Capitar IT Group BV <info@capitar.com>
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// Copyright 2020 Staysail Systems, Inc. <info@staysail.tech>
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//
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// This software is supplied under the terms of the MIT License, a
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// copy of which should be located in the distribution where this
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// file was obtained (LICENSE.txt). A copy of the license may also be
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// found online at https://opensource.org/licenses/MIT.
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//
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#include <stdlib.h>
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#include <string.h>
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#include "core/nng_impl.h"
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// Linked list implementation. We implement a doubly linked list.
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// Using pointer arithmetic, we can operate as a list of "anything".
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#define NODE(list, item) \
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(nni_list_node *) (void *)(((char *) item) + list->ll_offset)
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#define ITEM(list, node) (void *) (((char *) node) - list->ll_offset)
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void
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nni_list_init_offset(nni_list *list, size_t offset)
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{
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list->ll_offset = offset;
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list->ll_head.ln_next = &list->ll_head;
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list->ll_head.ln_prev = &list->ll_head;
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}
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void *
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nni_list_first(const nni_list *list)
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{
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nni_list_node *node = list->ll_head.ln_next;
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if (node == &list->ll_head) {
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return (NULL);
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}
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return (ITEM(list, node));
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}
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void *
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nni_list_last(const nni_list *list)
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{
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nni_list_node *node = list->ll_head.ln_prev;
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if (node == &list->ll_head) {
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return (NULL);
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}
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return (ITEM(list, node));
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}
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void
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nni_list_append(nni_list *list, void *item)
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{
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nni_list_node *node = NODE(list, item);
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if ((node->ln_next != NULL) || (node->ln_prev != NULL)) {
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nni_panic("appending node already on a list or not inited");
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}
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node->ln_prev = list->ll_head.ln_prev;
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node->ln_next = &list->ll_head;
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node->ln_next->ln_prev = node;
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node->ln_prev->ln_next = node;
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}
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void
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nni_list_prepend(nni_list *list, void *item)
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{
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nni_list_node *node = NODE(list, item);
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if ((node->ln_next != NULL) || (node->ln_prev != NULL)) {
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nni_panic("prepending node already on a list or not inited");
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}
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node->ln_next = list->ll_head.ln_next;
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node->ln_prev = &list->ll_head;
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node->ln_next->ln_prev = node;
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node->ln_prev->ln_next = node;
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}
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void
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nni_list_insert_before(nni_list *list, void *item, void *before)
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{
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nni_list_node *node = NODE(list, item);
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nni_list_node *where = NODE(list, before);
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if ((node->ln_next != NULL) || (node->ln_prev != NULL)) {
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nni_panic("inserting node already on a list or not inited");
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}
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node->ln_next = where;
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node->ln_prev = where->ln_prev;
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node->ln_next->ln_prev = node;
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node->ln_prev->ln_next = node;
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}
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void
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nni_list_insert_after(nni_list *list, void *item, void *after)
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{
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nni_list_node *node = NODE(list, item);
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nni_list_node *where = NODE(list, after);
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if ((node->ln_next != NULL) || (node->ln_prev != NULL)) {
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nni_panic("inserting node already on a list or not inited");
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}
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node->ln_prev = where;
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node->ln_next = where->ln_next;
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node->ln_next->ln_prev = node;
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node->ln_prev->ln_next = node;
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}
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void *
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nni_list_next(const nni_list *list, void *item)
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{
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nni_list_node *node = NODE(list, item);
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if (((node = node->ln_next) == &list->ll_head) || (node == NULL)) {
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return (NULL);
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}
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return (ITEM(list, node));
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}
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void *
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nni_list_prev(const nni_list *list, void *item)
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{
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nni_list_node *node = NODE(list, item);
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if (((node = node->ln_prev) == &list->ll_head) || (node == NULL)) {
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return (NULL);
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}
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return (ITEM(list, node));
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}
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void
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nni_list_remove(nni_list *list, void *item)
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{
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nni_list_node *node = NODE(list, item);
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node->ln_prev->ln_next = node->ln_next;
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node->ln_next->ln_prev = node->ln_prev;
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node->ln_next = NULL;
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node->ln_prev = NULL;
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}
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int
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nni_list_active(nni_list *list, void *item)
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{
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nni_list_node *node = NODE(list, item);
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return (node->ln_next == NULL ? 0 : 1);
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}
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int
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nni_list_empty(nni_list *list)
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{
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// The first check ensures that we treat an uninitialized list
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// as empty. This use useful for statically initialized lists.
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return ((list->ll_head.ln_next == NULL) ||
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(list->ll_head.ln_next == &list->ll_head));
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}
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int
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nni_list_node_active(nni_list_node *node)
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{
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return (node->ln_next == NULL ? 0 : 1);
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}
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void
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nni_list_node_remove(nni_list_node *node)
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{
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if (node->ln_next != NULL) {
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node->ln_prev->ln_next = node->ln_next;
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node->ln_next->ln_prev = node->ln_prev;
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node->ln_next = NULL;
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node->ln_prev = NULL;
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}
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}
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