700 lines
14 KiB
C
700 lines
14 KiB
C
/**
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* @file linked_list.c
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*
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* @brief Generic Double Linked List
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*
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*/
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/*
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* Copyright (C) 2005 Jan Hutter, Martin Willi
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* Hochschule fuer Technik Rapperswil
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version. See <http://www.fsf.org/copyleft/gpl.txt>.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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* or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*/
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#include <stdlib.h>
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#include "linked_list.h"
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#include "allocator.h"
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typedef struct linked_list_element_s linked_list_element_t;
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/**
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* @brief Element of the linked_list.
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*
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* This element holds a pointer to the value of the list item itself.
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*/
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struct linked_list_element_s{
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/**
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* value of a list item
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*/
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void *value;
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/**
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* @brief Destroys a linked_list_element object
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*
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* @param linked_list_element_t calling object
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* @returns SUCCESS if succeeded, FAILED otherwise
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*/
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status_t (*destroy) (linked_list_element_t *this);
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/**
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* previous list element
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* NULL if first element in list
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*/
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linked_list_element_t *previous;
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/**
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* next list element
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* NULL if last element in list
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*/
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linked_list_element_t *next;
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};
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/**
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* @brief implements function destroy of linked_list_item_t
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*/
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static status_t linked_list_element_destroy(linked_list_element_t *this)
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{
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if (this == NULL)
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{
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return FAILED;
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}
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allocator_free(this);
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return SUCCESS;
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}
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/**
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* @brief Creates an empty linked list object
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*
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* @param[in] value value of item to be set
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*
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* @warning only the pointer to the value is stored
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*
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* @return linked_list_element object
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*/
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linked_list_element_t *linked_list_element_create(void *value)
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{
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linked_list_element_t *this = allocator_alloc_thing(linked_list_element_t);
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if (this == NULL)
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{
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return NULL;
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}
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this->destroy = linked_list_element_destroy;
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this->previous=NULL;
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this->next=NULL;
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this->value = value;
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return (this);
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}
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/**
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* Private variables and functions of linked list
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*
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*/
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typedef struct private_linked_list_s private_linked_list_t;
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struct private_linked_list_s{
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/**
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* Public part of linked list
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*/
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linked_list_t public;
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/**
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* number of items in the list
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*/
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int count;
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/**
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* First element in list
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* NULL if no elements in list
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*/
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linked_list_element_t *first;
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/**
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* Last element in list
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* NULL if no elements in list
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*/
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linked_list_element_t *last;
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};
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/**
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* Private variables and functions of linked list iterator
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*
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*/
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typedef struct private_linked_list_iterator_s private_linked_list_iterator_t;
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struct private_linked_list_iterator_s{
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/**
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* Public part of linked list iterator
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*/
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linked_list_iterator_t public;
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/**
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* associated linked list
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*/
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private_linked_list_t * list;
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/**
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* current element of the iterator
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*/
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linked_list_element_t *current;
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/**
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* direction of iterator
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*/
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bool forward;
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};
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/**
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* Implements function has_next of linked_list_iteratr
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*/
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bool iterator_has_next(private_linked_list_iterator_t *this)
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{
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if (this->list->count == 0)
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{
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return FALSE;
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}
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if (this->current == NULL)
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{
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this->current = (this->forward) ? this->list->first : this->list->last;
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return TRUE;
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}
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if (this->forward)
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{
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if (this->current->next == NULL)
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{
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return FALSE;
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}
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this->current = this->current->next;
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return TRUE;
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}
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/* backward */
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if (this->current->previous == NULL)
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{
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return FALSE;
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}
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this->current = this->current->previous;
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return TRUE;
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}
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/**
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* Implements function current of linked_list_iteratr
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*/
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static status_t iterator_current(private_linked_list_iterator_t *this, void **value)
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{
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if (this == NULL)
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{
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return FAILED;
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}
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if (this->current == NULL)
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{
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return FAILED;
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}
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*value = this->current->value;
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return SUCCESS;
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}
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/**
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* Implements function current of linked_list_iteratr
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*/
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static status_t iterator_reset(private_linked_list_iterator_t *this)
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{
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if (this == NULL)
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{
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return FAILED;
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}
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this->current = NULL;
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return SUCCESS;
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}
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/**
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* Implements function destroy of linked_list_iteratr
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*/
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static status_t iterator_destroy(private_linked_list_iterator_t *this)
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{
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if (this == NULL)
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{
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return FAILED;
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}
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allocator_free(this);
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return SUCCESS;
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}
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/**
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* @brief implements function get_count of linked_list_t
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*/
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static int get_count(private_linked_list_t *this)
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{
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return this->count;
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}
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static status_t create_iterator (private_linked_list_t *linked_list, linked_list_iterator_t **iterator,bool forward)
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{
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private_linked_list_iterator_t *this = allocator_alloc_thing(private_linked_list_iterator_t);
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if (this == NULL)
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{
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return FAILED;
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}
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this->public.has_next = (bool (*) (linked_list_iterator_t *this)) iterator_has_next;
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this->public.current = (status_t (*) (linked_list_iterator_t *this, void **value)) iterator_current;
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this->public.reset = (status_t (*) (linked_list_iterator_t *this)) iterator_reset;
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this->public.destroy = (status_t (*) (linked_list_iterator_t *this)) iterator_destroy;
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this->forward = forward;
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this->current = NULL;
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this->list = linked_list;
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*iterator = &(this->public);
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return (SUCCESS);
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}
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/**
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* @brief implements function insert_first of linked_list_t
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*/
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static status_t insert_first(private_linked_list_t *this, void *item)
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{
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linked_list_element_t *element;
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if (this == NULL)
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{
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return FAILED;
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}
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element =(linked_list_element_t *) linked_list_element_create(item);
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if (element == NULL)
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{
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return FAILED;
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}
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if (this->count == 0)
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{
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/* first entry in list */
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this->first = element;
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this->last = element;
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element->previous = NULL;
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element->next = NULL;
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}
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else
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{
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if ((this->first == NULL) || (this->last == NULL))
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{
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/* should never happen */
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element->destroy(element);
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return FAILED;
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}
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linked_list_element_t *old_first_element = this->first;
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element->next = old_first_element;
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element->previous = NULL;
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old_first_element->previous = element;
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this->first = element;
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}
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this->count++;
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return SUCCESS;
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}
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/**
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* @brief implements function remove_first of linked_list_t
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*/
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static status_t remove_first(private_linked_list_t *this, void **item)
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{
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if (this == NULL)
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{
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return FAILED;
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}
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if (this->count == 0)
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{
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return FAILED;
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}
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if (this->first == NULL)
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{
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return FAILED;
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}
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linked_list_element_t *element = this->first;
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if (element->next != NULL)
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{
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element->next->previous = NULL;
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}
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this->first = element->next;
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*item = element->value;
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this->count--;
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return (element->destroy(element));
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}
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/**
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* @brief implements function get_first of linked_list_t
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*/
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static status_t get_first(private_linked_list_t *this, void **item)
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{
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if (this == NULL)
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{
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return FAILED;
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}
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if (this->count == 0)
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{
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return FAILED;
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}
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if (this->first == NULL)
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{
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return FAILED;
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}
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*item = this->first->value;
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return SUCCESS;
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}
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/**
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* @brief implements function insert_last of linked_list_t
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*/
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static status_t insert_last(private_linked_list_t *this, void *item)
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{
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if (this == NULL)
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{
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return FAILED;
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}
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linked_list_element_t *element = (linked_list_element_t *) linked_list_element_create(item);
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if (element == NULL)
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{
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return FAILED;
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}
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if (this->count == 0)
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{
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/* first entry in list */
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this->first = element;
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this->last = element;
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element->previous = NULL;
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element->next = NULL;
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}else
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{
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if ((this->first == NULL) || (this->last == NULL))
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{
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/* should never happen */
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element->destroy(element);
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return FAILED;
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}
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linked_list_element_t *old_last_element = this->last;
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element->previous = old_last_element;
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element->next = NULL;
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old_last_element->next = element;
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this->last = element;
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}
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this->count++;
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return SUCCESS;
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}
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/**
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* @brief implements function remove_last of linked_list_t
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*/
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static status_t remove_last(private_linked_list_t *this, void **item)
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{
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if (this == NULL)
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{
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return FAILED;
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}
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if (this->count == 0)
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{
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return FAILED;
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}
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if (this->last == NULL)
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{
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return FAILED;
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}
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linked_list_element_t *element = this->last;
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if (element->previous != NULL)
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{
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element->previous->next = NULL;
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}
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this->last = element->previous;
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*item = element->value;
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this->count--;
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return (element->destroy(element));
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}
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/**
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* @brief implements function get_last of linked_list_t
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*/
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static status_t get_last(private_linked_list_t *this, void **item)
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{
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if (this == NULL)
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{
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return FAILED;
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}
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if (this->count == 0)
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{
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return FAILED;
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}
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if (this->last == NULL)
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{
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return FAILED;
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}
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*item = this->last->value;
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return SUCCESS;
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}
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/**
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* @brief implements function insert_before of linked_list_t
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*/
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static status_t insert_before(private_linked_list_t *this, private_linked_list_iterator_t * iterator, void *item)
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{
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if ((this == NULL) || (iterator == NULL))
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{
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return FAILED;
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}
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if (this->count == 0)
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{
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return FAILED;
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}
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if (iterator->current == NULL)
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{
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return (this->public.insert_first(&this->public,item));
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}
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linked_list_element_t *element =(linked_list_element_t *) linked_list_element_create(item);
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if (element == NULL)
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{
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return FAILED;
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}
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if (iterator->current->previous == NULL)
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{
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if (this->first != iterator->current)
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{
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element->destroy(element);
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return FAILED;
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}
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iterator->current->previous = element;
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element->next = iterator->current;
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this->first = element;
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}
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else
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{
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iterator->current->previous->next = element;
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element->previous = iterator->current->previous;
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iterator->current->previous = element;
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element->next = iterator->current;
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}
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this->count++;
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return SUCCESS;
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}
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/**
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* @brief implements function insert_after of linked_list_t
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*/
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static status_t insert_after(private_linked_list_t *this, private_linked_list_iterator_t * iterator, void *item)
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{
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if ((this == NULL) || (iterator == NULL))
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{
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return FAILED;
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}
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if (this->count == 0)
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{
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return FAILED;
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}
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if (iterator->current == NULL)
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{
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return (this->public.insert_first(&this->public,item));
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}
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linked_list_element_t *element =(linked_list_element_t *) linked_list_element_create(item);
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if (element == NULL)
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{
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return FAILED;
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}
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if (iterator->current->next == NULL)
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{
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if (this->last != iterator->current)
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{
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element->destroy(element);
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return FAILED;
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}
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iterator->current->next = element;
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element->previous = iterator->current;
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this->last = element;
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}
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else
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{
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iterator->current->next->previous = element;
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element->next = iterator->current->next;
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iterator->current->next = element;
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element->previous = iterator->current;
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}
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this->count++;
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return SUCCESS;
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}
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/**
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* @brief implements function remove of linked_list_t
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*/
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static status_t linked_list_remove(private_linked_list_t *this, private_linked_list_iterator_t * iterator)
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{
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linked_list_element_t *new_current;
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if ((this == NULL) || (iterator == NULL) || (iterator->current == NULL))
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{
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return FAILED;
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}
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if (this->count == 0)
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{
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return FAILED;
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}
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/* find out the new iterator position */
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if (iterator->current->previous != NULL)
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{
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new_current = iterator->current->previous;
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}
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else if (iterator->current->next != NULL)
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{
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new_current = iterator->current->next;
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}
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else
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{
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new_current = NULL;
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}
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/* now delete the entry :-) */
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if (iterator->current->previous == NULL)
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{
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if (iterator->current->next == NULL)
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{
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this->first = NULL;
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this->last = NULL;
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}
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else
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{
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iterator->current->next->previous = NULL;
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this->first = iterator->current->next;
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}
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}
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else if (iterator->current->next == NULL)
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{
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iterator->current->previous->next = NULL;
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this->last = iterator->current->previous;
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}
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else
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{
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iterator->current->previous->next = iterator->current->next;
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iterator->current->next->previous = iterator->current->previous;
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}
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this->count--;
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iterator->current->destroy(iterator->current);
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/* set the new iterator position */
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iterator->current = new_current;
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return SUCCESS;
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}
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/**
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* @brief implements function destroy of linked_list_t
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*/
|
|
static status_t linked_list_destroy(private_linked_list_t *this)
|
|
{
|
|
if (this == NULL)
|
|
{
|
|
return FAILED;
|
|
}
|
|
|
|
/* Remove all list items before destroying list */
|
|
while (this->count > 0)
|
|
{
|
|
void * value;
|
|
/* values are not destroyed so memory leaks are possible
|
|
* if list is not empty when deleting */
|
|
if (this->public.remove_first(&(this->public),&value) != SUCCESS)
|
|
{
|
|
allocator_free(this);
|
|
return FAILED;
|
|
}
|
|
}
|
|
allocator_free(this);
|
|
return SUCCESS;
|
|
}
|
|
|
|
/*
|
|
* Described in header
|
|
*/
|
|
linked_list_t *linked_list_create()
|
|
{
|
|
private_linked_list_t *this = allocator_alloc_thing(private_linked_list_t);
|
|
|
|
this->public.get_count = (int (*) (linked_list_t *linked_list)) get_count;
|
|
this->public.create_iterator = (status_t (*) (linked_list_t *linked_list, linked_list_iterator_t **iterator,bool forward)) create_iterator;
|
|
this->public.get_first = (status_t (*) (linked_list_t *linked_list, void **item)) get_first;
|
|
this->public.get_last = (status_t (*) (linked_list_t *linked_list, void **item)) get_last;
|
|
this->public.insert_first = (status_t (*) (linked_list_t *linked_list, void *item)) insert_first;
|
|
this->public.insert_last = (status_t (*) (linked_list_t *linked_list, void *item)) insert_last;
|
|
this->public.insert_before = (status_t (*) (linked_list_t *linked_list, linked_list_iterator_t * element, void *item)) insert_before;
|
|
this->public.insert_after = (status_t (*) (linked_list_t *linked_list, linked_list_iterator_t * element, void *item)) insert_after;
|
|
this->public.remove = (status_t (*) (linked_list_t *linked_list, linked_list_iterator_t * element)) linked_list_remove;
|
|
this->public.remove_first = (status_t (*) (linked_list_t *linked_list, void **item)) remove_first;
|
|
this->public.remove_last = (status_t (*) (linked_list_t *linked_list, void **item)) remove_last;
|
|
this->public.destroy = (status_t (*) (linked_list_t *linked_list)) linked_list_destroy;
|
|
|
|
this->count = 0;
|
|
this->first = NULL;
|
|
this->last = NULL;
|
|
|
|
return (&(this->public));
|
|
}
|