Mon, 20 Dec 2021 11:58:36 +0100
add more nonnull attributes
This also changes the contract for last/first in the sense that these
functions now also require a valid pointer.
1 /*
2 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
3 *
4 * Copyright 2021 Mike Becker, Olaf Wintermann All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are met:
8 *
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 *
12 * 2. Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
17 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
20 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
26 * POSSIBILITY OF SUCH DAMAGE.
27 */
28 /**
29 * \file linked_list.h
30 * \brief Linked list implementation.
31 * \details Also provides several low-level functions for custom linked list implementations.
32 * \author Mike Becker
33 * \author Olaf Wintermann
34 * \version 3.0
35 * \copyright 2-Clause BSD License
36 */
38 #ifndef UCX_LINKED_LIST_H
39 #define UCX_LINKED_LIST_H
41 #include <stddef.h>
42 #include "list.h"
44 #ifdef __cplusplus
45 extern "C" {
46 #endif
48 /**
49 * Allocates a linked list for storing elements with \p item_size bytes each.
50 *
51 * Elements added to the list are copied.
52 *
53 * @param allocator the allocator for allocating the list nodes
54 * @param comparator the comparator for the elements
55 * @param item_size the size of each element in bytes
56 * @return the created list
57 */
58 CxList cxLinkedListCreate(CxAllocator allocator, CxListComparator comparator, size_t item_size);
60 /**
61 * Allocates a linked list for storing pointers.
62 *
63 * If you want to store the elements directly in this list, use cxLinkedListCreate().
64 *
65 * @param allocator the allocator for allocating the list nodes
66 * @param comparator the comparator for the elements
67 * @return the created list
68 */
69 CxList cxPointerLinkedListCreate(CxAllocator allocator, CxListComparator comparator);
71 /**
72 * Deallocates the memory of the entire list.
73 *
74 * \attention If this is a pointer list, the memory the pointers are referring to is \em not freed.
75 *
76 * @param list the list
77 */
78 void cxLinkedListDestroy(CxList list);
80 /**
81 * Finds the node at a certain index.
82 *
83 * This function can be used to start at an arbitrary position within the list.
84 * If the search index is large than the start index, \p loc_advance must denote
85 * the location of some sort of \c next pointer (i.e. a pointer to the next node).
86 * But it is also possible that the search index is smaller than the start index
87 * (e.g. in cases where traversing a list backwards is faster) in which case
88 * \p loc_advance must denote the location of some sort of \c prev pointer
89 * (i.e. a pointer to the previous node).
90 *
91 * @param start a pointer to the start node
92 * @param start_index the start index
93 * @param loc_advance the location of the pointer to advance
94 * @param index the search index
95 * @return the node found at the specified index
96 */
97 void *cx_linked_list_at(void *start, size_t start_index, ptrdiff_t loc_advance, size_t index)
98 __attribute__((__nonnull__));
100 /**
101 * Finds the first node in a linked list.
102 *
103 * The function starts with the pointer denoted by \p node and traverses the list
104 * along a prev pointer whose location within the node struct is
105 * denoted by \p loc_prev.
106 *
107 * @param node a pointer to a node in the list
108 * @param loc_prev the location of the \c prev pointer
109 */
110 void *cx_linked_list_first(void *node, ptrdiff_t loc_prev)
111 __attribute__((__nonnull__));
113 /**
114 * Finds the last node in a linked list.
115 *
116 * The function starts with the pointer denoted by \p node and traverses the list
117 * along a next pointer whose location within the node struct is
118 * denoted by \p loc_next.
119 *
120 * @param node a pointer to a node in the list
121 * @param loc_next the location of the \c next pointer
122 * @return a pointer to the last node
123 */
124 void *cx_linked_list_last(void *node, ptrdiff_t loc_next)
125 __attribute__((__nonnull__));
127 /**
128 * Finds the predecessor of a node in case it is not linked.
129 *
130 * \remark If \p node is not contained in the list starting with \p begin, the behavior is undefined.
131 *
132 * @param begin the node where to start the search
133 * @param loc_next the location of the \c next pointer
134 * @param node the successor of the node to find
135 * @return the node or \c NULL if \p node has no predecessor
136 */
137 void *cx_linked_list_prev(void *begin, ptrdiff_t loc_next, void *node)
138 __attribute__((__nonnull__));
140 /**
141 * Adds a new node to a linked list.
142 * The node must not be part of any list already.
143 *
144 * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
145 *
146 * @param begin a pointer to the begin node pointer (if your list has one)
147 * @param end a pointer to the end node pointer (if your list has one)
148 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
149 * @param loc_next the location of a \c next pointer within your node struct (required)
150 * @param new_node a pointer to the node that shall be appended
151 */
152 void cx_linked_list_add(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *new_node)
153 __attribute__((__nonnull__(5)));
155 /**
156 * Prepends a new node to a linked list.
157 * The node must not be part of any list already.
158 *
159 * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
160 *
161 * @param begin a pointer to the begin node pointer (if your list has one)
162 * @param end a pointer to the end node pointer (if your list has one)
163 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
164 * @param loc_next the location of a \c next pointer within your node struct (required)
165 * @param new_node a pointer to the node that shall be prepended
166 */
167 void cx_linked_list_prepend(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *new_node)
168 __attribute__((__nonnull__(5)));
170 /**
171 * Removes a node from the linked list.
172 *
173 * If the node to remove is the begin (resp. end) node of the list and if \p begin (resp. \p end)
174 * addresses are provided, the pointers are adjusted accordingly.
175 *
176 * The following combinations of arguments are valid (more arguments are optional):
177 * \li \p loc_next and \p loc_prev (ancestor node is determined by using the prev pointer, overall O(1) performance)
178 * \li \p loc_next and \p begin (ancestor node is determined by list traversal, overall O(n) performance)
179 *
180 * \remark The \c next and \c prev pointers of the removed node are not cleared by this function and may still be used
181 * to traverse to a former adjacent node in the list.
182 *
183 * @param begin a pointer to the begin node pointer (optional)
184 * @param end a pointer to the end node pointer (optional)
185 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
186 * @param loc_next the location of a \c next pointer within your node struct (required)
187 * @param node the node to remove
188 */
189 void cx_linked_list_remove(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *node)
190 __attribute__((__nonnull__(5)));
193 /**
194 * Determines the size of a linked list starting with \p node.
195 * @param node the first node
196 * @param loc_next the location of the \c next pointer within the node struct
197 * @return the size of the list or zero if \p node is \c NULL
198 */
199 size_t cx_linked_list_size(void *node, ptrdiff_t loc_next);
201 /**
202 * Sorts a linked list based on a comparison function.
203 *
204 * This function can work with linked lists of the following structures:
205 * \code
206 * typedef struct node node;
207 * struct node {
208 * node* prev;
209 * node* next;
210 * my_payload data; // in this case set follow_ptr = 0
211 * }
212 *
213 * typedef struct ptr_node ptr_node;
214 * struct ptr_node {
215 * ptr_node* prev;
216 * ptr_node* next;
217 * my_payload* data; // in this case set follow_ptr = 1
218 * }
219 * \endcode
220 *
221 * @note This is a recursive function with at most logarithmic recursion depth.
222 *
223 * @param begin a pointer to the begin node pointer (required)
224 * @param end a pointer to the end node pointer (optional)
225 * @param loc_prev the location of a \c prev pointer within your node struct (negative if not present)
226 * @param loc_next the location of a \c next pointer within your node struct (required)
227 * @param loc_data the location of the \c data pointer within your node struct
228 * @param follow_ptr \c false if the pointer denoted by \p loc_data shall be passed to the \p cmp_func.
229 * If \c true, the data at \p loc_data is dereferenced, assuming to be a pointer, and then passed to \p cmp_func.
230 * @param cmp_func the compare function defining the sort order
231 */
232 void cx_linked_list_sort(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next,
233 ptrdiff_t loc_data, int follow_ptr, CxListComparator cmp_func)
234 __attribute__((__nonnull__(1, 7)));
237 /**
238 * Reverses the order of the nodes in a linked list.
239 *
240 * @param begin a pointer to the begin node pointer (required)
241 * @param end a pointer to the end node pointer (optional)
242 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
243 * @param loc_next the location of a \c next pointer within your node struct (required)
244 */
245 void cx_linked_list_reverse(void **begin, void **end, ptrdiff_t loc_prev, ptrdiff_t loc_next)
246 __attribute__((__nonnull__(1)));
248 #ifdef __cplusplus
249 } /* extern "C" */
250 #endif
252 #endif /* UCX_LINKED_LIST_H */