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 #include "cx/linked_list.h"
30 #include "cx/utils.h"
31 #include <string.h>
32 #include <assert.h>
33
34 // LOW LEVEL LINKED LIST FUNCTIONS
35
36 #define CX_LL_PTR(cur, off) (*(void**)(((char*)(cur))+(off)))
37 #define ll_prev(node) CX_LL_PTR(node, loc_prev)
38 #define ll_next(node) CX_LL_PTR(node, loc_next)
39 #define ll_advance(node) CX_LL_PTR(node, loc_advance)
40 #define ll_data(node) (((char*)(node))+loc_data)
41
42 void *cx_linked_list_at(
43 void const *start,
44 size_t start_index,
45 ptrdiff_t loc_advance,
46 size_t index
47 ) {
48 assert(start != NULL);
49 assert(loc_advance >= 0);
50 size_t i = start_index;
51 void const *cur = start;
52 while (i != index && cur != NULL) {
53 cur = ll_advance(cur);
54 i < index ? i++ : i--;
55 }
56 return (void *) cur;
57 }
58
59 ssize_t cx_linked_list_find(
60 void const *start,
61 ptrdiff_t loc_advance,
62 ptrdiff_t loc_data,
63 cx_compare_func cmp_func,
64 void const *elem
65 ) {
66 assert(start != NULL);
67 assert(loc_advance >= 0);
68 assert(loc_data >= 0);
69 assert(cmp_func);
70
71 void const *node = start;
72 ssize_t index = 0;
73 do {
74 void *current = ll_data(node);
75 if (cmp_func(current, elem) == 0) {
76 return index;
77 }
78 node = ll_advance(node);
79 index++;
80 } while (node != NULL);
81 return -1;
82 }
83
84 void *cx_linked_list_first(
85 void const *node,
86 ptrdiff_t loc_prev
87 ) {
88 return cx_linked_list_last(node, loc_prev);
89 }
90
91 void *cx_linked_list_last(
92 void const *node,
93 ptrdiff_t loc_next
94 ) {
95 assert(node != NULL);
96 assert(loc_next >= 0);
97
98 void const *cur = node;
99 void const *last;
100 do {
101 last = cur;
102 } while ((cur = ll_next(cur)) != NULL);
103
104 return (void *) last;
105 }
106
107 void *cx_linked_list_prev(
108 void const *begin,
109 ptrdiff_t loc_next,
110 void const *node
111 ) {
112 assert(begin != NULL);
113 assert(node != NULL);
114 assert(loc_next >= 0);
115 if (begin == node) return NULL;
116 void const *cur = begin;
117 void const *next;
118 while (1) {
119 next = ll_next(cur);
120 if (next == node) return (void *) cur;
121 cur = next;
122 }
123 }
124
125 void cx_linked_list_link(
126 void *left,
127 void *right,
128 ptrdiff_t loc_prev,
129 ptrdiff_t loc_next
130 ) {
131 assert(loc_next >= 0);
132 ll_next(left) = right;
133 if (loc_prev >= 0) {
134 ll_prev(right) = left;
135 }
136 }
137
138 void cx_linked_list_unlink(
139 void *left,
140 void *right,
141 ptrdiff_t loc_prev,
142 ptrdiff_t loc_next
143 ) {
144 assert (loc_next >= 0);
145 assert(ll_next(left) == right);
146 ll_next(left) = NULL;
147 if (loc_prev >= 0) {
148 assert(ll_prev(right) == left);
149 ll_prev(right) = NULL;
150 }
151 }
152
153 void cx_linked_list_add(
154 void **begin,
155 void **end,
156 ptrdiff_t loc_prev,
157 ptrdiff_t loc_next,
158 void *new_node
159 ) {
160 void *last;
161 if (end == NULL) {
162 assert(begin != NULL);
163 last = *begin == NULL ? NULL : cx_linked_list_last(*begin, loc_next);
164 } else {
165 last = *end;
166 }
167 cx_linked_list_insert_chain(begin, end, loc_prev, loc_next, last, new_node, new_node);
168 }
169
170 void cx_linked_list_prepend(
171 void **begin,
172 void **end,
173 ptrdiff_t loc_prev,
174 ptrdiff_t loc_next,
175 void *new_node
176 ) {
177 cx_linked_list_insert_chain(begin, end, loc_prev, loc_next, NULL, new_node, new_node);
178 }
179
180 void cx_linked_list_insert(
181 void **begin,
182 void **end,
183 ptrdiff_t loc_prev,
184 ptrdiff_t loc_next,
185 void *node,
186 void *new_node
187 ) {
188 cx_linked_list_insert_chain(begin, end, loc_prev, loc_next, node, new_node, new_node);
189 }
190
191 void cx_linked_list_insert_chain(
192 void **begin,
193 void **end,
194 ptrdiff_t loc_prev,
195 ptrdiff_t loc_next,
196 void *node,
197 void *insert_begin,
198 void *insert_end
199 ) {
200 // find the end of the chain, if not specified
201 if (insert_end == NULL) {
202 insert_end = cx_linked_list_last(insert_begin, loc_next);
203 }
204
205 // determine the successor
206 void *successor;
207 if (node == NULL) {
208 assert(begin != NULL || (end != NULL && loc_prev >= 0));
209 if (begin != NULL) {
210 successor = *begin;
211 *begin = insert_begin;
212 } else {
213 successor = *end == NULL ? NULL : cx_linked_list_first(*end, loc_prev);
214 }
215 } else {
216 successor = ll_next(node);
217 cx_linked_list_link(node, insert_begin, loc_prev, loc_next);
218 }
219
220 if (successor == NULL) {
221 // the list ends with the new chain
222 if (end != NULL) {
223 *end = insert_end;
224 }
225 } else {
226 cx_linked_list_link(insert_end, successor, loc_prev, loc_next);
227 }
228 }
229
230 void cx_linked_list_remove(
231 void **begin,
232 void **end,
233 ptrdiff_t loc_prev,
234 ptrdiff_t loc_next,
235 void *node
236 ) {
237 assert(node != NULL);
238 assert(loc_next >= 0);
239 assert(loc_prev >= 0 || begin != NULL);
240
241 // find adjacent nodes
242 void *next = ll_next(node);
243 void *prev;
244 if (loc_prev >= 0) {
245 prev = ll_prev(node);
246 } else {
247 prev = cx_linked_list_prev(*begin, loc_next, node);
248 }
249
250 // update next pointer of prev node, or set begin
251 if (prev == NULL) {
252 if (begin != NULL) {
253 *begin = next;
254 }
255 } else {
256 ll_next(prev) = next;
257 }
258
259 // update prev pointer of next node, or set end
260 if (next == NULL) {
261 if (end != NULL) {
262 *end = prev;
263 }
264 } else if (loc_prev >= 0) {
265 ll_prev(next) = prev;
266 }
267 }
268
269 size_t cx_linked_list_size(
270 void const *node,
271 ptrdiff_t loc_next
272 ) {
273 assert(loc_next >= 0);
274 size_t size = 0;
275 while (node != NULL) {
276 node = ll_next(node);
277 size++;
278 }
279 return size;
280 }
281
282 #ifndef CX_LINKED_LIST_SORT_SBO_SIZE
283 #define CX_LINKED_LIST_SORT_SBO_SIZE 1024
284 #endif
285
286 static void cx_linked_list_sort_merge(
287 ptrdiff_t loc_prev,
288 ptrdiff_t loc_next,
289 ptrdiff_t loc_data,
290 size_t length,
291 void *ls,
292 void *le,
293 void *re,
294 cx_compare_func cmp_func,
295 void **begin,
296 void **end
297 ) {
298 void *sbo[CX_LINKED_LIST_SORT_SBO_SIZE];
299 void **sorted = length >= CX_LINKED_LIST_SORT_SBO_SIZE ?
300 malloc(sizeof(void *) * length) : sbo;
301 if (sorted == NULL) abort();
302 void *rc, *lc;
303
304 lc = ls;
305 rc = le;
306 size_t n = 0;
307 while (lc && lc != le && rc != re) {
308 if (cmp_func(ll_data(lc), ll_data(rc)) <= 0) {
309 sorted[n] = lc;
310 lc = ll_next(lc);
311 } else {
312 sorted[n] = rc;
313 rc = ll_next(rc);
314 }
315 n++;
316 }
317 while (lc && lc != le) {
318 sorted[n] = lc;
319 lc = ll_next(lc);
320 n++;
321 }
322 while (rc && rc != re) {
323 sorted[n] = rc;
324 rc = ll_next(rc);
325 n++;
326 }
327
328 // Update pointer
329 if (loc_prev >= 0) ll_prev(sorted[0]) = NULL;
330 cx_for_n (i, length - 1) {
331 cx_linked_list_link(sorted[i], sorted[i + 1], loc_prev, loc_next);
332 }
333 ll_next(sorted[length - 1]) = NULL;
334
335 *begin = sorted[0];
336 *end = sorted[length-1];
337 if (sorted != sbo) {
338 free(sorted);
339 }
340 }
341
342 void cx_linked_list_sort( // NOLINT(misc-no-recursion) - purposely recursive function
343 void **begin,
344 void **end,
345 ptrdiff_t loc_prev,
346 ptrdiff_t loc_next,
347 ptrdiff_t loc_data,
348 cx_compare_func cmp_func
349 ) {
350 assert(begin != NULL);
351 assert(loc_next >= 0);
352 assert(loc_data >= 0);
353 assert(cmp_func);
354
355 void *lc, *ls, *le, *re;
356
357 // set start node
358 ls = *begin;
359
360 // early exit when this list is empty
361 if (ls == NULL) return;
362
363 // check how many elements are already sorted
364 lc = ls;
365 size_t ln = 1;
366 while (ll_next(lc) != NULL && cmp_func(ll_data(ll_next(lc)), ll_data(lc)) > 0) {
367 lc = ll_next(lc);
368 ln++;
369 }
370 le = ll_next(lc);
371
372 // if first unsorted node is NULL, the list is already completely sorted
373 if (le != NULL) {
374 void *rc;
375 size_t rn = 1;
376 rc = le;
377 // skip already sorted elements
378 while (ll_next(rc) != NULL && cmp_func(ll_data(ll_next(rc)), ll_data(rc)) > 0) {
379 rc = ll_next(rc);
380 rn++;
381 }
382 re = ll_next(rc);
383
384 // {ls,...,le->prev} and {rs,...,re->prev} are sorted - merge them
385 void *sorted_begin, *sorted_end;
386 cx_linked_list_sort_merge(loc_prev, loc_next, loc_data,
387 ln + rn, ls, le, re, cmp_func,
388 &sorted_begin, &sorted_end);
389
390 // Something left? Sort it!
391 size_t remainder_length = cx_linked_list_size(re, loc_next);
392 if (remainder_length > 0) {
393 void *remainder = re;
394 cx_linked_list_sort(&remainder, NULL, loc_prev, loc_next, loc_data, cmp_func);
395
396 // merge sorted list with (also sorted) remainder
397 cx_linked_list_sort_merge(loc_prev, loc_next, loc_data,
398 ln + rn + remainder_length,
399 sorted_begin, remainder, NULL, cmp_func,
400 &sorted_begin, &sorted_end);
401 }
402 *begin = sorted_begin;
403 if (end) *end = sorted_end;
404 }
405 }
406
407 int cx_linked_list_compare(
408 void const *begin_left,
409 void const *begin_right,
410 ptrdiff_t loc_advance,
411 ptrdiff_t loc_data,
412 cx_compare_func cmp_func
413 ) {
414 void const *left = begin_left, *right = begin_right;
415
416 while (left != NULL && right != NULL) {
417 void const *left_data = ll_data(left);
418 void const *right_data = ll_data(right);
419 int result = cmp_func(left_data, right_data);
420 if (result != 0) return result;
421 left = ll_advance(left);
422 right = ll_advance(right);
423 }
424
425 if (left != NULL) { return 1; }
426 else if (right != NULL) { return -1; }
427 else { return 0; }
428 }
429
430 void cx_linked_list_reverse(
431 void **begin,
432 void **end,
433 ptrdiff_t loc_prev,
434 ptrdiff_t loc_next
435 ) {
436 assert(begin != NULL);
437 assert(loc_next >= 0);
438
439 // swap all links
440 void *prev = NULL;
441 void *cur = *begin;
442 while (cur != NULL) {
443 void *next = ll_next(cur);
444
445 ll_next(cur) = prev;
446 if (loc_prev >= 0) {
447 ll_prev(cur) = next;
448 }
449
450 prev = cur;
451 cur = next;
452 }
453
454 // update begin and end
455 if (end != NULL) {
456 *end = *begin;
457 }
458 *begin = prev;
459 }
460
461 // HIGH LEVEL LINKED LIST IMPLEMENTATION
462
463 bool CX_DISABLE_LINKED_LIST_SWAP_SBO = false;
464
465 typedef struct cx_linked_list_node cx_linked_list_node;
466 struct cx_linked_list_node {
467 cx_linked_list_node *prev;
468 cx_linked_list_node *next;
469 char payload[];
470 };
471
472 #define CX_LL_LOC_PREV offsetof(cx_linked_list_node, prev)
473 #define CX_LL_LOC_NEXT offsetof(cx_linked_list_node, next)
474 #define CX_LL_LOC_DATA offsetof(cx_linked_list_node, payload)
475
476 typedef struct {
477 struct cx_list_s base;
478 cx_linked_list_node *begin;
479 cx_linked_list_node *end;
480 } cx_linked_list;
481
482 static cx_linked_list_node *cx_ll_node_at(
483 cx_linked_list const *list,
484 size_t index
485 ) {
486 if (index >= list->base.size) {
487 return NULL;
488 } else if (index > list->base.size / 2) {
489 return cx_linked_list_at(list->end, list->base.size - 1, CX_LL_LOC_PREV, index);
490 } else {
491 return cx_linked_list_at(list->begin, 0, CX_LL_LOC_NEXT, index);
492 }
493 }
494
495 static int cx_ll_insert_at(
496 struct cx_list_s *list,
497 cx_linked_list_node *node,
498 void const *elem
499 ) {
500
501 // create the new new_node
502 cx_linked_list_node *new_node = cxMalloc(list->allocator,
503 sizeof(cx_linked_list_node) + list->item_size);
504
505 // sortir if failed
506 if (new_node == NULL) return 1;
507
508 // initialize new new_node
509 new_node->prev = new_node->next = NULL;
510 memcpy(new_node->payload, elem, list->item_size);
511
512 // insert
513 cx_linked_list *ll = (cx_linked_list *) list;
514 cx_linked_list_insert_chain(
515 (void **) &ll->begin, (void **) &ll->end,
516 CX_LL_LOC_PREV, CX_LL_LOC_NEXT,
517 node, new_node, new_node
518 );
519
520 // increase the size and return
521 list->size++;
522 return 0;
523 }
524
525 static size_t cx_ll_insert_array(
526 struct cx_list_s *list,
527 size_t index,
528 void const *array,
529 size_t n
530 ) {
531 // out-of bounds and corner case check
532 if (index > list->size || n == 0) return 0;
533
534 // find position efficiently
535 cx_linked_list_node *node = index == 0 ? NULL : cx_ll_node_at((cx_linked_list *) list, index - 1);
536
537 // perform first insert
538 if (0 != cx_ll_insert_at(list, node, array)) {
539 return 1;
540 }
541
542 // is there more?
543 if (n == 1) return 1;
544
545 // we now know exactly where we are
546 node = node == NULL ? ((cx_linked_list *) list)->begin : node->next;
547
548 // we can add the remaining nodes and immedately advance to the inserted node
549 char const *source = array;
550 for (size_t i = 1; i < n; i++) {
551 source += list->item_size;
552 if (0 != cx_ll_insert_at(list, node, source)) {
553 return i;
554 }
555 node = node->next;
556 }
557 return n;
558 }
559
560 static int cx_ll_insert_element(
561 struct cx_list_s *list,
562 size_t index,
563 void const *element
564 ) {
565 return 1 != cx_ll_insert_array(list, index, element, 1);
566 }
567
568 static int cx_ll_remove(
569 struct cx_list_s *list,
570 size_t index
571 ) {
572 cx_linked_list *ll = (cx_linked_list *) list;
573 cx_linked_list_node *node = cx_ll_node_at(ll, index);
574
575 // out-of-bounds check
576 if (node == NULL) return 1;
577
578 // element destruction
579 cx_invoke_destructor(list, node->payload);
580
581 // remove
582 cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end,
583 CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node);
584
585 // adjust size
586 list->size--;
587
588 // free and return
589 cxFree(list->allocator, node);
590
591 return 0;
592 }
593
594 static void cx_ll_clear(struct cx_list_s *list) {
595 if (list->size == 0) return;
596
597 cx_linked_list *ll = (cx_linked_list *) list;
598 cx_linked_list_node *node = ll->begin;
599 while (node != NULL) {
600 cx_invoke_destructor(list, node->payload);
601 cx_linked_list_node *next = node->next;
602 cxFree(list->allocator, node);
603 node = next;
604 }
605 ll->begin = ll->end = NULL;
606 list->size = 0;
607 }
608
609 #ifndef CX_LINKED_LIST_SWAP_SBO_SIZE
610 #define CX_LINKED_LIST_SWAP_SBO_SIZE 128
611 #endif
612
613 static int cx_ll_swap(
614 struct cx_list_s *list,
615 size_t i,
616 size_t j
617 ) {
618 if (i >= list->size || j >= list->size) return 1;
619 if (i == j) return 0;
620
621 // perform an optimized search that finds both elements in one run
622 cx_linked_list *ll = (cx_linked_list *) list;
623 size_t mid = list->size / 2;
624 size_t left, right;
625 if (i < j) {
626 left = i;
627 right = j;
628 } else {
629 left = j;
630 right = i;
631 }
632 cx_linked_list_node *nleft, *nright;
633 if (left < mid && right < mid) {
634 // case 1: both items left from mid
635 nleft = cx_ll_node_at(ll, left);
636 nright = nleft;
637 for (size_t c = left; c < right; c++) {
638 nright = nright->next;
639 }
640 } else if (left >= mid && right >= mid) {
641 // case 2: both items right from mid
642 nright = cx_ll_node_at(ll, right);
643 nleft = nright;
644 for (size_t c = right; c > left; c--) {
645 nleft = nleft->prev;
646 }
647 } else {
648 // case 3: one item left, one item right
649
650 // chose the closest to begin / end
651 size_t closest;
652 size_t other;
653 size_t diff2boundary = list->size - right - 1;
654 if (left <= diff2boundary) {
655 closest = left;
656 other = right;
657 nleft = cx_ll_node_at(ll, left);
658 } else {
659 closest = right;
660 other = left;
661 diff2boundary = left;
662 nright = cx_ll_node_at(ll, right);
663 }
664
665 // is other element closer to us or closer to boundary?
666 if (right - left <= diff2boundary) {
667 // search other element starting from already found element
668 if (closest == left) {
669 nright = nleft;
670 for (size_t c = left; c < right; c++) {
671 nright = nright->next;
672 }
673 } else {
674 nleft = nright;
675 for (size_t c = right; c > left; c--) {
676 nleft = nleft->prev;
677 }
678 }
679 } else {
680 // search other element starting at the boundary
681 if (closest == left) {
682 nright = cx_ll_node_at(ll, other);
683 } else {
684 nleft = cx_ll_node_at(ll, other);
685 }
686 }
687 }
688
689 if (list->item_size > CX_LINKED_LIST_SWAP_SBO_SIZE || CX_DISABLE_LINKED_LIST_SWAP_SBO) {
690 cx_linked_list_node *prev = nleft->prev;
691 cx_linked_list_node *next = nright->next;
692 cx_linked_list_node *midstart = nleft->next;
693 cx_linked_list_node *midend = nright->prev;
694
695 if (prev == NULL) {
696 ll->begin = nright;
697 } else {
698 prev->next = nright;
699 }
700 nright->prev = prev;
701 if (midstart == nright) {
702 // special case: both nodes are adjacent
703 nright->next = nleft;
704 nleft->prev = nright;
705 } else {
706 // likely case: a chain is between the two nodes
707 nright->next = midstart;
708 midstart->prev = nright;
709 midend->next = nleft;
710 nleft->prev = midend;
711 }
712 nleft->next = next;
713 if (next == NULL) {
714 ll->end = nleft;
715 } else {
716 next->prev = nleft;
717 }
718 } else {
719 // swap payloads to avoid relinking
720 char buf[CX_LINKED_LIST_SWAP_SBO_SIZE];
721 memcpy(buf, nleft->payload, list->item_size);
722 memcpy(nleft->payload, nright->payload, list->item_size);
723 memcpy(nright->payload, buf, list->item_size);
724 }
725
726 return 0;
727 }
728
729 static void *cx_ll_at(
730 struct cx_list_s const *list,
731 size_t index
732 ) {
733 cx_linked_list *ll = (cx_linked_list *) list;
734 cx_linked_list_node *node = cx_ll_node_at(ll, index);
735 return node == NULL ? NULL : node->payload;
736 }
737
738 static ssize_t cx_ll_find(
739 struct cx_list_s const *list,
740 void const *elem
741 ) {
742 return cx_linked_list_find(((cx_linked_list *) list)->begin,
743 CX_LL_LOC_NEXT, CX_LL_LOC_DATA,
744 list->cmpfunc, elem);
745 }
746
747 static void cx_ll_sort(struct cx_list_s *list) {
748 cx_linked_list *ll = (cx_linked_list *) list;
749 cx_linked_list_sort((void **) &ll->begin, (void **) &ll->end,
750 CX_LL_LOC_PREV, CX_LL_LOC_NEXT, CX_LL_LOC_DATA,
751 list->cmpfunc);
752 }
753
754 static void cx_ll_reverse(struct cx_list_s *list) {
755 cx_linked_list *ll = (cx_linked_list *) list;
756 cx_linked_list_reverse((void **) &ll->begin, (void **) &ll->end, CX_LL_LOC_PREV, CX_LL_LOC_NEXT);
757 }
758
759 static int cx_ll_compare(
760 struct cx_list_s const *list,
761 struct cx_list_s const *other
762 ) {
763 cx_linked_list *left = (cx_linked_list *) list;
764 cx_linked_list *right = (cx_linked_list *) other;
765 return cx_linked_list_compare(left->begin, right->begin,
766 CX_LL_LOC_NEXT, CX_LL_LOC_DATA,
767 list->cmpfunc);
768 }
769
770 static bool cx_ll_iter_valid(void const *it) {
771 struct cx_iterator_s const *iter = it;
772 return iter->elem_handle != NULL;
773 }
774
775 static void cx_ll_iter_next(void *it) {
776 struct cx_iterator_base_s *itbase = it;
777 if (itbase->remove) {
778 itbase->remove = false;
779 struct cx_mut_iterator_s *iter = it;
780 struct cx_list_s *list = iter->src_handle;
781 cx_linked_list *ll = iter->src_handle;
782 cx_linked_list_node *node = iter->elem_handle;
783 iter->elem_handle = node->next;
784 cx_invoke_destructor(list, node->payload);
785 cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end,
786 CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node);
787 list->size--;
788 cxFree(list->allocator, node);
789 } else {
790 struct cx_iterator_s *iter = it;
791 iter->index++;
792 cx_linked_list_node *node = iter->elem_handle;
793 iter->elem_handle = node->next;
794 }
795 }
796
797 static void cx_ll_iter_prev(void *it) {
798 struct cx_iterator_base_s *itbase = it;
799 if (itbase->remove) {
800 itbase->remove = false;
801 struct cx_mut_iterator_s *iter = it;
802 struct cx_list_s *list = iter->src_handle;
803 cx_linked_list *ll = iter->src_handle;
804 cx_linked_list_node *node = iter->elem_handle;
805 iter->elem_handle = node->prev;
806 iter->index--;
807 cx_invoke_destructor(list, node->payload);
808 cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end,
809 CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node);
810 list->size--;
811 cxFree(list->allocator, node);
812 } else {
813 struct cx_iterator_s *iter = it;
814 iter->index--;
815 cx_linked_list_node *node = iter->elem_handle;
816 iter->elem_handle = node->prev;
817 }
818 }
819
820 static void *cx_ll_iter_current(void const *it) {
821 struct cx_iterator_s const *iter = it;
822 cx_linked_list_node *node = iter->elem_handle;
823 return node->payload;
824 }
825
826 static bool cx_ll_iter_flag_rm(void *it) {
827 struct cx_iterator_base_s *iter = it;
828 if (iter->mutating) {
829 iter->remove = true;
830 return true;
831 } else {
832 return false;
833 }
834 }
835
836 static CxIterator cx_ll_iterator(
837 struct cx_list_s const *list,
838 size_t index,
839 bool backwards
840 ) {
841 CxIterator iter;
842 iter.index = index;
843 iter.src_handle = list;
844 iter.elem_handle = cx_ll_node_at((cx_linked_list const *) list, index);
845 iter.base.valid = cx_ll_iter_valid;
846 iter.base.current = cx_ll_iter_current;
847 iter.base.next = backwards ? cx_ll_iter_prev : cx_ll_iter_next;
848 iter.base.flag_removal = cx_ll_iter_flag_rm;
849 iter.base.mutating = false;
850 iter.base.remove = false;
851 return iter;
852 }
853
854 static int cx_ll_insert_iter(
855 CxMutIterator *iter,
856 void const *elem,
857 int prepend
858 ) {
859 struct cx_list_s *list = iter->src_handle;
860 cx_linked_list_node *node = iter->elem_handle;
861 if (node != NULL) {
862 assert(prepend >= 0 && prepend <= 1);
863 cx_linked_list_node *choice[2] = {node, node->prev};
864 int result = cx_ll_insert_at(list, choice[prepend], elem);
865 iter->index += prepend * (0 == result);
866 return result;
867 } else {
868 int result = cx_ll_insert_element(list, list->size, elem);
869 iter->index = list->size;
870 return result;
871 }
872 }
873
874 static void cx_ll_destructor(CxList *list) {
875 cx_linked_list *ll = (cx_linked_list *) list;
876
877 cx_linked_list_node *node = ll->begin;
878 while (node) {
879 cx_invoke_destructor(list, node->payload);
880 void *next = node->next;
881 cxFree(list->allocator, node);
882 node = next;
883 }
884
885 cxFree(list->allocator, list);
886 }
887
888 static cx_list_class cx_linked_list_class = {
889 cx_ll_destructor,
890 cx_ll_insert_element,
891 cx_ll_insert_array,
892 cx_ll_insert_iter,
893 cx_ll_remove,
894 cx_ll_clear,
895 cx_ll_swap,
896 cx_ll_at,
897 cx_ll_find,
898 cx_ll_sort,
899 cx_ll_compare,
900 cx_ll_reverse,
901 cx_ll_iterator,
902 };
903
904 CxList *cxLinkedListCreate(
905 CxAllocator const *allocator,
906 cx_compare_func comparator,
907 size_t item_size
908 ) {
909 if (allocator == NULL) {
910 allocator = cxDefaultAllocator;
911 }
912
913 cx_linked_list *list = cxCalloc(allocator, 1, sizeof(cx_linked_list));
914 if (list == NULL) return NULL;
915
916 list->base.cl = &cx_linked_list_class;
917 list->base.allocator = allocator;
918 list->base.cmpfunc = comparator;
919
920 if (item_size > 0) {
921 list->base.item_size = item_size;
922 } else {
923 cxListStorePointers((CxList *) list);
924 }
925
926 return (CxList *) list;
927 }
928