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 * \copyright 2-Clause BSD License
35 */
36
37 #ifndef UCX_LINKED_LIST_H
38 #define UCX_LINKED_LIST_H
39
40 #include "common.h"
41 #include "list.h"
42
43 #ifdef __cplusplus
44 extern "C" {
45 #endif
46
47 /**
48 * The maximum item size that uses SBO swap instead of relinking.
49 */
50 extern unsigned cx_linked_list_swap_sbo_size;
51
52 /**
53 * Allocates a linked list for storing elements with \p elem_size bytes each.
54 *
55 * If \p elem_size is CX_STORE_POINTERS, the created list will be created as if
56 * cxListStorePointers() was called immediately after creation and the compare
57 * function will be automatically set to cx_cmp_ptr(), if none is given.
58 *
59 * @param allocator the allocator for allocating the list nodes
60 * (if \c NULL the cxDefaultAllocator will be used)
61 * @param comparator the comparator for the elements
62 * (if \c NULL, and the list is not storing pointers, sort and find
63 * functions will not work)
64 * @param elem_size the size of each element in bytes
65 * @return the created list
66 */
67 CxList *cxLinkedListCreate(
68 CxAllocator const *allocator,
69 cx_compare_func comparator,
70 size_t elem_size
71 );
72
73 /**
74 * Allocates a linked list for storing elements with \p elem_size bytes each.
75 *
76 * The list will use cxDefaultAllocator and no comparator function. If you want
77 * to call functions that need a comparator, you must either set one immediately
78 * after list creation or use cxLinkedListCreate().
79 *
80 * If \p elem_size is CX_STORE_POINTERS, the created list will be created as if
81 * cxListStorePointers() was called immediately after creation and the compare
82 * function will be automatically set to cx_cmp_ptr().
83 *
84 * @param elem_size the size of each element in bytes
85 * @return the created list
86 */
87 #define cxLinkedListCreateSimple(elem_size) \
88 cxLinkedListCreate(NULL, NULL, elem_size)
89
90 /**
91 * Finds the node at a certain index.
92 *
93 * This function can be used to start at an arbitrary position within the list.
94 * If the search index is large than the start index, \p loc_advance must denote
95 * the location of some sort of \c next pointer (i.e. a pointer to the next node).
96 * But it is also possible that the search index is smaller than the start index
97 * (e.g. in cases where traversing a list backwards is faster) in which case
98 * \p loc_advance must denote the location of some sort of \c prev pointer
99 * (i.e. a pointer to the previous node).
100 *
101 * @param start a pointer to the start node
102 * @param start_index the start index
103 * @param loc_advance the location of the pointer to advance
104 * @param index the search index
105 * @return the node found at the specified index
106 */
107 void *cx_linked_list_at(
108 void const *start,
109 size_t start_index,
110 ptrdiff_t loc_advance,
111 size_t index
112 ) __attribute__((__nonnull__));
113
114 /**
115 * Finds the index of an element within a linked list.
116 *
117 * @param start a pointer to the start node
118 * @param loc_advance the location of the pointer to advance
119 * @param loc_data the location of the \c data pointer within your node struct
120 * @param cmp_func a compare function to compare \p elem against the node data
121 * @param elem a pointer to the element to find
122 * @return the index of the element or a negative value if it could not be found
123 */
124 ssize_t cx_linked_list_find(
125 void const *start,
126 ptrdiff_t loc_advance,
127 ptrdiff_t loc_data,
128 cx_compare_func cmp_func,
129 void const *elem
130 ) __attribute__((__nonnull__));
131
132 /**
133 * Finds the node containing an element within a linked list.
134 *
135 * @param result a pointer to the memory where the node pointer (or \c NULL if the element
136 * could not be found) shall be stored to
137 * @param start a pointer to the start node
138 * @param loc_advance the location of the pointer to advance
139 * @param loc_data the location of the \c data pointer within your node struct
140 * @param cmp_func a compare function to compare \p elem against the node data
141 * @param elem a pointer to the element to find
142 * @return the index of the element or a negative value if it could not be found
143 */
144 ssize_t cx_linked_list_find_node(
145 void **result,
146 void const *start,
147 ptrdiff_t loc_advance,
148 ptrdiff_t loc_data,
149 cx_compare_func cmp_func,
150 void const *elem
151 ) __attribute__((__nonnull__));
152
153 /**
154 * Finds the first node in a linked list.
155 *
156 * The function starts with the pointer denoted by \p node and traverses the list
157 * along a prev pointer whose location within the node struct is
158 * denoted by \p loc_prev.
159 *
160 * @param node a pointer to a node in the list
161 * @param loc_prev the location of the \c prev pointer
162 * @return a pointer to the first node
163 */
164 void *cx_linked_list_first(
165 void const *node,
166 ptrdiff_t loc_prev
167 ) __attribute__((__nonnull__));
168
169 /**
170 * Finds the last node in a linked list.
171 *
172 * The function starts with the pointer denoted by \p node and traverses the list
173 * along a next pointer whose location within the node struct is
174 * denoted by \p loc_next.
175 *
176 * @param node a pointer to a node in the list
177 * @param loc_next the location of the \c next pointer
178 * @return a pointer to the last node
179 */
180 void *cx_linked_list_last(
181 void const *node,
182 ptrdiff_t loc_next
183 ) __attribute__((__nonnull__));
184
185 /**
186 * Finds the predecessor of a node in case it is not linked.
187 *
188 * \remark If \p node is not contained in the list starting with \p begin, the behavior is undefined.
189 *
190 * @param begin the node where to start the search
191 * @param loc_next the location of the \c next pointer
192 * @param node the successor of the node to find
193 * @return the node or \c NULL if \p node has no predecessor
194 */
195 void *cx_linked_list_prev(
196 void const *begin,
197 ptrdiff_t loc_next,
198 void const *node
199 ) __attribute__((__nonnull__));
200
201 /**
202 * Adds a new node to a linked list.
203 * The node must not be part of any list already.
204 *
205 * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
206 *
207 * @param begin a pointer to the begin node pointer (if your list has one)
208 * @param end a pointer to the end node pointer (if your list has one)
209 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
210 * @param loc_next the location of a \c next pointer within your node struct (required)
211 * @param new_node a pointer to the node that shall be appended
212 */
213 void cx_linked_list_add(
214 void **begin,
215 void **end,
216 ptrdiff_t loc_prev,
217 ptrdiff_t loc_next,
218 void *new_node
219 ) __attribute__((__nonnull__(5)));
220
221 /**
222 * Prepends a new node to a linked list.
223 * The node must not be part of any list already.
224 *
225 * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
226 *
227 * @param begin a pointer to the begin node pointer (if your list has one)
228 * @param end a pointer to the end node pointer (if your list has one)
229 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
230 * @param loc_next the location of a \c next pointer within your node struct (required)
231 * @param new_node a pointer to the node that shall be prepended
232 */
233 void cx_linked_list_prepend(
234 void **begin,
235 void **end,
236 ptrdiff_t loc_prev,
237 ptrdiff_t loc_next,
238 void *new_node
239 ) __attribute__((__nonnull__(5)));
240
241 /**
242 * Links two nodes.
243 *
244 * @param left the new predecessor of \p right
245 * @param right the new successor of \p left
246 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
247 * @param loc_next the location of a \c next pointer within your node struct (required)
248 */
249 void cx_linked_list_link(
250 void *left,
251 void *right,
252 ptrdiff_t loc_prev,
253 ptrdiff_t loc_next
254 ) __attribute__((__nonnull__));
255
256 /**
257 * Unlinks two nodes.
258 *
259 * If right is not the successor of left, the behavior is undefined.
260 *
261 * @param left the predecessor of \p right
262 * @param right the successor of \p left
263 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
264 * @param loc_next the location of a \c next pointer within your node struct (required)
265 */
266 void cx_linked_list_unlink(
267 void *left,
268 void *right,
269 ptrdiff_t loc_prev,
270 ptrdiff_t loc_next
271 ) __attribute__((__nonnull__));
272
273 /**
274 * Inserts a new node after a given node of a linked list.
275 * The new node must not be part of any list already.
276 *
277 * \note If you specify \c NULL as the \p node to insert after, this function needs either the \p begin or
278 * the \p end pointer to determine the start of the list. Then the new node will be prepended to the list.
279 *
280 * @param begin a pointer to the begin node pointer (if your list has one)
281 * @param end a pointer to the end node pointer (if your list has one)
282 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
283 * @param loc_next the location of a \c next pointer within your node struct (required)
284 * @param node the node after which to insert (\c NULL if you want to prepend the node to the list)
285 * @param new_node a pointer to the node that shall be prepended
286 */
287 void cx_linked_list_insert(
288 void **begin,
289 void **end,
290 ptrdiff_t loc_prev,
291 ptrdiff_t loc_next,
292 void *node,
293 void *new_node
294 ) __attribute__((__nonnull__(6)));
295
296 /**
297 * Inserts a chain of nodes after a given node of a linked list.
298 * The chain must not be part of any list already.
299 *
300 * If you do not explicitly specify the end of the chain, it will be determined by traversing
301 * the \c next pointer.
302 *
303 * \note If you specify \c NULL as the \p node to insert after, this function needs either the \p begin or
304 * the \p end pointer to determine the start of the list. If only the \p end pointer is specified, you also need
305 * to provide a valid \p loc_prev location.
306 * Then the chain will be prepended to the list.
307 *
308 * @param begin a pointer to the begin node pointer (if your list has one)
309 * @param end a pointer to the end node pointer (if your list has one)
310 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
311 * @param loc_next the location of a \c next pointer within your node struct (required)
312 * @param node the node after which to insert (\c NULL to prepend the chain to the list)
313 * @param insert_begin a pointer to the first node of the chain that shall be inserted
314 * @param insert_end a pointer to the last node of the chain (or NULL if the last node shall be determined)
315 */
316 void cx_linked_list_insert_chain(
317 void **begin,
318 void **end,
319 ptrdiff_t loc_prev,
320 ptrdiff_t loc_next,
321 void *node,
322 void *insert_begin,
323 void *insert_end
324 ) __attribute__((__nonnull__(6)));
325
326 /**
327 * Removes a node from the linked list.
328 *
329 * If the node to remove is the begin (resp. end) node of the list and if \p begin (resp. \p end)
330 * addresses are provided, the pointers are adjusted accordingly.
331 *
332 * The following combinations of arguments are valid (more arguments are optional):
333 * \li \p loc_next and \p loc_prev (ancestor node is determined by using the prev pointer, overall O(1) performance)
334 * \li \p loc_next and \p begin (ancestor node is determined by list traversal, overall O(n) performance)
335 *
336 * \remark The \c next and \c prev pointers of the removed node are not cleared by this function and may still be used
337 * to traverse to a former adjacent node in the list.
338 *
339 * @param begin a pointer to the begin node pointer (optional)
340 * @param end a pointer to the end node pointer (optional)
341 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
342 * @param loc_next the location of a \c next pointer within your node struct (required)
343 * @param node the node to remove
344 */
345 void cx_linked_list_remove(
346 void **begin,
347 void **end,
348 ptrdiff_t loc_prev,
349 ptrdiff_t loc_next,
350 void *node
351 ) __attribute__((__nonnull__(5)));
352
353
354 /**
355 * Determines the size of a linked list starting with \p node.
356 * @param node the first node
357 * @param loc_next the location of the \c next pointer within the node struct
358 * @return the size of the list or zero if \p node is \c NULL
359 */
360 size_t cx_linked_list_size(
361 void const *node,
362 ptrdiff_t loc_next
363 );
364
365 /**
366 * Sorts a linked list based on a comparison function.
367 *
368 * This function can work with linked lists of the following structure:
369 * \code
370 * typedef struct node node;
371 * struct node {
372 * node* prev;
373 * node* next;
374 * my_payload data;
375 * }
376 * \endcode
377 *
378 * @note This is a recursive function with at most logarithmic recursion depth.
379 *
380 * @param begin a pointer to the begin node pointer (required)
381 * @param end a pointer to the end node pointer (optional)
382 * @param loc_prev the location of a \c prev pointer within your node struct (negative if not present)
383 * @param loc_next the location of a \c next pointer within your node struct (required)
384 * @param loc_data the location of the \c data pointer within your node struct
385 * @param cmp_func the compare function defining the sort order
386 */
387 void cx_linked_list_sort(
388 void **begin,
389 void **end,
390 ptrdiff_t loc_prev,
391 ptrdiff_t loc_next,
392 ptrdiff_t loc_data,
393 cx_compare_func cmp_func
394 ) __attribute__((__nonnull__(1, 6)));
395
396
397 /**
398 * Compares two lists element wise.
399 *
400 * \note Both list must have the same structure.
401 *
402 * @param begin_left the begin of the left list (\c NULL denotes an empty list)
403 * @param begin_right the begin of the right list (\c NULL denotes an empty list)
404 * @param loc_advance the location of the pointer to advance
405 * @param loc_data the location of the \c data pointer within your node struct
406 * @param cmp_func the function to compare the elements
407 * @return the first non-zero result of invoking \p cmp_func or: negative if the left list is smaller than the
408 * right list, positive if the left list is larger than the right list, zero if both lists are equal.
409 */
410 int cx_linked_list_compare(
411 void const *begin_left,
412 void const *begin_right,
413 ptrdiff_t loc_advance,
414 ptrdiff_t loc_data,
415 cx_compare_func cmp_func
416 ) __attribute__((__nonnull__(5)));
417
418 /**
419 * Reverses the order of the nodes in a linked list.
420 *
421 * @param begin a pointer to the begin node pointer (required)
422 * @param end a pointer to the end node pointer (optional)
423 * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
424 * @param loc_next the location of a \c next pointer within your node struct (required)
425 */
426 void cx_linked_list_reverse(
427 void **begin,
428 void **end,
429 ptrdiff_t loc_prev,
430 ptrdiff_t loc_next
431 ) __attribute__((__nonnull__(1)));
432
433 #ifdef __cplusplus
434 } // extern "C"
435 #endif
436
437 #endif // UCX_LINKED_LIST_H
438