mirror of https://github.com/c-ares/c-ares.git
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/* $Id$ */ |
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/* Copyright 1998 by the Massachusetts Institute of Technology.
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* |
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* Permission to use, copy, modify, and distribute this |
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* software and its documentation for any purpose and without |
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* fee is hereby granted, provided that the above copyright |
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* notice appear in all copies and that both that copyright |
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* notice and this permission notice appear in supporting |
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* documentation, and that the name of M.I.T. not be used in |
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* advertising or publicity pertaining to distribution of the |
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* software without specific, written prior permission. |
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* M.I.T. makes no representations about the suitability of |
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* this software for any purpose. It is provided "as is" |
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* without express or implied warranty. |
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*/ |
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#include "setup.h" |
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#include "ares.h" |
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#include "ares_private.h" |
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/* Routines for managing doubly-linked circular linked lists with a
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* dummy head. |
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*/ |
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/* Initialize a new head node */ |
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void ares__init_list_head(struct list_node* head) { |
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head->prev = head; |
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head->next = head; |
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head->data = NULL; |
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} |
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/* Initialize a list node */ |
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void ares__init_list_node(struct list_node* node, void* d) { |
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node->prev = NULL; |
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node->next = NULL; |
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node->data = d; |
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} |
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/* Returns true iff the given list is empty */ |
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int ares__is_list_empty(struct list_node* head) { |
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return ((head->next == head) && (head->prev == head)); |
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} |
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/* Inserts new_node before old_node */ |
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void ares__insert_in_list(struct list_node* new_node, |
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struct list_node* old_node) { |
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new_node->next = old_node; |
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new_node->prev = old_node->prev; |
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old_node->prev->next = new_node; |
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old_node->prev = new_node; |
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} |
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/* Removes the node from the list it's in, if any */ |
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void ares__remove_from_list(struct list_node* node) { |
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if (node->next != NULL) { |
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node->prev->next = node->next; |
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node->next->prev = node->prev; |
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node->prev = NULL; |
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node->next = NULL; |
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} |
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} |
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/* Swap the contents of two lists */ |
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void ares__swap_lists(struct list_node* head_a, |
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struct list_node* head_b) { |
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int is_a_empty = ares__is_list_empty(head_a); |
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int is_b_empty = ares__is_list_empty(head_b); |
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struct list_node old_a = *head_a; |
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struct list_node old_b = *head_b; |
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if (is_a_empty) { |
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ares__init_list_head(head_b); |
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} else { |
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*head_b = old_a; |
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old_a.next->prev = head_b; |
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old_a.prev->next = head_b; |
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} |
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if (is_b_empty) { |
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ares__init_list_head(head_a); |
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} else { |
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*head_a = old_b; |
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old_b.next->prev = head_a; |
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old_b.prev->next = head_a; |
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} |
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} |
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#ifndef __ARES_LLIST_H |
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#define __ARES_LLIST_H |
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/* $Id$ */ |
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/* Copyright 1998 by the Massachusetts Institute of Technology.
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* |
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* Permission to use, copy, modify, and distribute this |
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* software and its documentation for any purpose and without |
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* fee is hereby granted, provided that the above copyright |
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* notice appear in all copies and that both that copyright |
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* notice and this permission notice appear in supporting |
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* documentation, and that the name of M.I.T. not be used in |
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* advertising or publicity pertaining to distribution of the |
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* software without specific, written prior permission. |
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* M.I.T. makes no representations about the suitability of |
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* this software for any purpose. It is provided "as is" |
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* without express or implied warranty. |
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*/ |
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/* Node definition for circular, doubly-linked list */ |
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struct list_node { |
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struct list_node *prev; |
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struct list_node *next; |
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void* data; |
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}; |
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void ares__init_list_head(struct list_node* head); |
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void ares__init_list_node(struct list_node* node, void* d); |
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int ares__is_list_empty(struct list_node* head); |
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void ares__insert_in_list(struct list_node* new_node, |
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struct list_node* old_node); |
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void ares__remove_from_list(struct list_node* node); |
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void ares__swap_lists(struct list_node* head_a, |
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struct list_node* head_b); |
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#endif /* __ARES_LLIST_H */ |
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