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 /*

  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

  *

  * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.

  *

  * Redistribution and use in source and binary forms, with or without

  * modification, are permitted provided that the following conditions are met:

  *

  *   1. Redistributions of source code must retain the above copyright

  *      notice, this list of conditions and the following disclaimer.

  *

  *   2. Redistributions in binary form must reproduce the above copyright

  *      notice, this list of conditions and the following disclaimer in the

  *      documentation and/or other materials provided with the distribution.

  *

  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"

  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

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  */

 /**

  * \file linked_list.h

  * \brief Linked list implementation.

  * \details Also provides several low-level functions for custom linked list implementations.

  * \author Mike Becker

  * \author Olaf Wintermann

  * \version 3.0

  * \copyright 2-Clause BSD License

  */

 #ifndef UCX_LINKED_LIST_H

 #define UCX_LINKED_LIST_H

 #include <stddef.h>

 #include "list.h"

 #ifdef __cplusplus

 extern "C" {

 #endif

 /**

  * Allocates a linked list for storing elements with \p item_size bytes each.

  *

  * Elements added to the list are copied.

  *

  * @param allocator the allocator for allocating the list nodes

  * @param comparator the comparator for the elements

  * @param item_size the size of each element in bytes

  * @return the created list

  */

 CxList cxLinkedListCreate(CxAllocator allocator, CxListComparator comparator, size_t item_size);

 /**

  * Allocates a linked list for storing pointers.

  *

  * If you want to store the elements directly in this list, use cxLinkedListCreate().

  *

  * @param allocator the allocator for allocating the list nodes

  * @param comparator the comparator for the elements

  * @return the created list

  */

 CxList cxPointerLinkedListCreate(CxAllocator allocator, CxListComparator comparator);

 /**

  * Deallocates the memory of the entire list.

  *

  * \attention If this is a pointer list, the memory the pointers are referring to is \em not freed.

  *

  * @param list the list

  */

 void cxLinkedListDestroy(CxList list);

 /**

  * Finds the node at a certain index.

  *

  * This function can be used to start at an arbitrary position within the list.

  * If the search index is large than the start index, \p loc_advance must denote

  * the location of some sort of \c next pointer (i.e. a pointer to the next node).

  * But it is also possible that the search index is smaller than the start index

  * (e.g. in cases where traversing a list backwards is faster) in which case

  * \p loc_advance must denote the location of some sort of \c prev pointer

  * (i.e. a pointer to the previous node).

  *

  * @param start a pointer to the start node

  * @param start_index the start index

  * @param loc_advance the location of the pointer to advance

  * @param index the search index

  * @return the node found at the specified index

  */

 void *cx_linked_list_at(void *start, size_t start_index, ptrdiff_t loc_advance, size_t index);

 /**

  * Finds the first node in a linked list.

  *

  * The function starts with the pointer denoted by \p node and traverses the list

  * along a prev pointer whose location within the node struct is

  * denoted by \p loc_prev.

  *

  * @param node a pointer to a node in the list

  * @param loc_prev the location of the \c prev pointer

  * @return a pointer to the first node or \c NULL if \p node is \c NULL

  */

 void *cx_linked_list_first(void *node, ptrdiff_t loc_prev);

 /**

  * Finds the last node in a linked list.

  *

  * The function starts with the pointer denoted by \p node and traverses the list

  * along a next pointer whose location within the node struct is

  * denoted by \p loc_next.

  *

  * @param node a pointer to a node in the list

  * @param loc_next the location of the \c next pointer

  * @return a pointer to the last node or \c NULL if \p begin is \c NULL

  */

 void *cx_linked_list_last(void *node, ptrdiff_t loc_next);

 /**

  * Finds the predecessor of a node in case it is not linked.

  *

  * \remark If \p node is not contained in the list starting with \p begin, the behavior is undefined.

  *

  * @param begin the node where to start the search

  * @param loc_next the location of the \c next pointer

  * @param node the successor of the node to find

  * @return the node or \c NULL if \p node has no predecessor

  */

 void *cx_linked_list_prev(void *begin, ptrdiff_t loc_next, void *node);

 /**

  * Adds a new node to a linked list.

  * The node must not be part of any list already.

  *

  * \remark One of the pointers \p begin and \p end may be \c NULL, but not both.

  *

  * @param begin a pointer to the begin node pointer (if your list has one)

  * @param end a pointer to the end node pointer (if your list has one)

  * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)

  * @param loc_next the location of a \c next pointer within your node struct (required)

  * @param new_node a pointer to the node that shall be appended

  */

 void cx_linked_list_add(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *new_node);

 /**

  * Prepends a new node to a linked list.

  * The node must not be part of any list already.

  *

  * \remark One of the pointers \p begin and \p end may be \c NULL, but not both.

  *

  * @param begin a pointer to the begin node pointer (if your list has one)

  * @param end a pointer to the end node pointer (if your list has one)

  * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)

  * @param loc_next the location of a \c next pointer within your node struct (required)

  * @param new_node a pointer to the node that shall be prepended

  */

 void cx_linked_list_prepend(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *new_node);

 /**

  * Removes a node from the linked list.

  *

  * If the node to remove is the begin (resp. end) node of the list and if \p begin (resp. \p end)

  * addresses are provided, the pointers are adjusted accordingly.

  *

  * The following combinations of arguments are valid (more arguments are optional):

  * \li \p loc_next and \p loc_prev

  * \li \p loc_next and \p begin

  *

  * This function returns an adjacent node according to the following rules:

  * \li if the node has only one adjacent node, that one is returned

  * \li otherwise, the former \c prev node is returned

  *

  * \remark The \c next and \c prev pointers of the removed node are cleared by this function.

  *

  * @param begin a pointer to the begin node pointer (optional)

  * @param end a pointer to the end node pointer (optional)

  * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)

  * @param loc_next the location of a \c next pointer within your node struct (required)

  * @param node the node to remove

  * @return an adjacent node or \c NULL, if this was the last node

  */

 void *cx_linked_list_remove(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *node);

 /**

  * Determines the size of a linked list starting with \p node.

  * @param node the first node

  * @param loc_next the location of the \c next pointer within the node struct

  * @return the size of the list or zero if \p node is \c NULL

  */

 size_t cx_linked_list_size(void *node, ptrdiff_t loc_next);

 /**

  * Sorts a linked list based on a comparison function.

  *

  * This function can work with linked lists of the following structures:

  * \code

  * typedef struct node node;

  * struct node {

  *   node* prev;

  *   node* next;

  *   my_payload data; // in this case set follow_ptr = 0

  * }

  *

  * typedef struct ptr_node ptr_node;

  * struct ptr_node {

  *   ptr_node* prev;

  *   ptr_node* next;

  *   my_payload* data; // in this case set follow_ptr = 1

  * }

  * \endcode

  *

  * @param begin a pointer to the begin node pointer (required)

  * @param end a pointer to the end node pointer (optional)

  * @param loc_prev the location of a \c prev pointer within your node struct (negative if not present)

  * @param loc_next the location of a \c next pointer within your node struct (required)

  * @param loc_data the location of the \c data pointer within your node struct

  * @param follow_ptr \c false if the pointer denoted by \p loc_data shall be passed to the \p cmp_func.

  * If \c true, the data at \p loc_data is dereferenced, assuming to be a pointer, and then passed to \p cmp_func.

  * @param cmp_func the compare function defining the sort order

  */

 void cx_linked_list_sort(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next,

                          ptrdiff_t loc_data, int follow_ptr, CxListComparator cmp_func);

 /**

  * Reverses the order of the nodes in a linked list.

  *

  * @param begin a pointer to the begin node pointer (required)

  * @param end a pointer to the end node pointer (optional)

  * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)

  * @param loc_next the location of a \c next pointer within your node struct (required)

  */

 void cx_linked_list_reverse(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next);

 #ifdef __cplusplus

 } /* extern "C" */

 #endif

 #endif /* UCX_LINKED_LIST_H */