--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/linked_list.c Sat Jan 04 16:38:48 2025 +0100
@@ -0,0 +1,1117 @@
+/*
+ * 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
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "cx/linked_list.h"
+#include "cx/utils.h"
+#include "cx/compare.h"
+#include <string.h>
+#include <assert.h>
+
+// LOW LEVEL LINKED LIST FUNCTIONS
+
+#define CX_LL_PTR(cur, off) (*(void**)(((char*)(cur))+(off)))
+#define ll_prev(node) CX_LL_PTR(node, loc_prev)
+#define ll_next(node) CX_LL_PTR(node, loc_next)
+#define ll_advance(node) CX_LL_PTR(node, loc_advance)
+#define ll_data(node) (((char*)(node))+loc_data)
+
+void *cx_linked_list_at(
+ const void *start,
+ size_t start_index,
+ ptrdiff_t loc_advance,
+ size_t index
+) {
+ assert(start != NULL);
+ assert(loc_advance >= 0);
+ size_t i = start_index;
+ const void *cur = start;
+ while (i != index && cur != NULL) {
+ cur = ll_advance(cur);
+ i < index ? i++ : i--;
+ }
+ return (void *) cur;
+}
+
+ssize_t cx_linked_list_find(
+ const void *start,
+ ptrdiff_t loc_advance,
+ ptrdiff_t loc_data,
+ cx_compare_func cmp_func,
+ const void *elem
+) {
+ void *dummy;
+ return cx_linked_list_find_node(
+ &dummy, start,
+ loc_advance, loc_data,
+ cmp_func, elem
+ );
+}
+
+ssize_t cx_linked_list_find_node(
+ void **result,
+ const void *start,
+ ptrdiff_t loc_advance,
+ ptrdiff_t loc_data,
+ cx_compare_func cmp_func,
+ const void *elem
+) {
+ assert(result != NULL);
+ assert(start != NULL);
+ assert(loc_advance >= 0);
+ assert(loc_data >= 0);
+ assert(cmp_func);
+
+ const void *node = start;
+ ssize_t index = 0;
+ do {
+ void *current = ll_data(node);
+ if (cmp_func(current, elem) == 0) {
+ *result = (void*) node;
+ return index;
+ }
+ node = ll_advance(node);
+ index++;
+ } while (node != NULL);
+ *result = NULL;
+ return -1;
+}
+
+void *cx_linked_list_first(
+ const void *node,
+ ptrdiff_t loc_prev
+) {
+ return cx_linked_list_last(node, loc_prev);
+}
+
+void *cx_linked_list_last(
+ const void *node,
+ ptrdiff_t loc_next
+) {
+ assert(node != NULL);
+ assert(loc_next >= 0);
+
+ const void *cur = node;
+ const void *last;
+ do {
+ last = cur;
+ } while ((cur = ll_next(cur)) != NULL);
+
+ return (void *) last;
+}
+
+void *cx_linked_list_prev(
+ const void *begin,
+ ptrdiff_t loc_next,
+ const void *node
+) {
+ assert(begin != NULL);
+ assert(node != NULL);
+ assert(loc_next >= 0);
+ if (begin == node) return NULL;
+ const void *cur = begin;
+ const void *next;
+ while (1) {
+ next = ll_next(cur);
+ if (next == node) return (void *) cur;
+ cur = next;
+ }
+}
+
+void cx_linked_list_link(
+ void *left,
+ void *right,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ assert(loc_next >= 0);
+ ll_next(left) = right;
+ if (loc_prev >= 0) {
+ ll_prev(right) = left;
+ }
+}
+
+void cx_linked_list_unlink(
+ void *left,
+ void *right,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ assert (loc_next >= 0);
+ assert(ll_next(left) == right);
+ ll_next(left) = NULL;
+ if (loc_prev >= 0) {
+ assert(ll_prev(right) == left);
+ ll_prev(right) = NULL;
+ }
+}
+
+void cx_linked_list_add(
+ void **begin,
+ void **end,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next,
+ void *new_node
+) {
+ void *last;
+ if (end == NULL) {
+ assert(begin != NULL);
+ last = *begin == NULL ? NULL : cx_linked_list_last(*begin, loc_next);
+ } else {
+ last = *end;
+ }
+ cx_linked_list_insert_chain(begin, end, loc_prev, loc_next, last, new_node, new_node);
+}
+
+void cx_linked_list_prepend(
+ void **begin,
+ void **end,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next,
+ void *new_node
+) {
+ cx_linked_list_insert_chain(begin, end, loc_prev, loc_next, NULL, new_node, new_node);
+}
+
+void cx_linked_list_insert(
+ void **begin,
+ void **end,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next,
+ void *node,
+ void *new_node
+) {
+ cx_linked_list_insert_chain(begin, end, loc_prev, loc_next, node, new_node, new_node);
+}
+
+void cx_linked_list_insert_chain(
+ void **begin,
+ void **end,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next,
+ void *node,
+ void *insert_begin,
+ void *insert_end
+) {
+ // find the end of the chain, if not specified
+ if (insert_end == NULL) {
+ insert_end = cx_linked_list_last(insert_begin, loc_next);
+ }
+
+ // determine the successor
+ void *successor;
+ if (node == NULL) {
+ assert(begin != NULL || (end != NULL && loc_prev >= 0));
+ if (begin != NULL) {
+ successor = *begin;
+ *begin = insert_begin;
+ } else {
+ successor = *end == NULL ? NULL : cx_linked_list_first(*end, loc_prev);
+ }
+ } else {
+ successor = ll_next(node);
+ cx_linked_list_link(node, insert_begin, loc_prev, loc_next);
+ }
+
+ if (successor == NULL) {
+ // the list ends with the new chain
+ if (end != NULL) {
+ *end = insert_end;
+ }
+ } else {
+ cx_linked_list_link(insert_end, successor, loc_prev, loc_next);
+ }
+}
+
+void cx_linked_list_insert_sorted(
+ void **begin,
+ void **end,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next,
+ void *new_node,
+ cx_compare_func cmp_func
+) {
+ assert(ll_next(new_node) == NULL);
+ cx_linked_list_insert_sorted_chain(
+ begin, end, loc_prev, loc_next, new_node, cmp_func);
+}
+
+void cx_linked_list_insert_sorted_chain(
+ void **begin,
+ void **end,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next,
+ void *insert_begin,
+ cx_compare_func cmp_func
+) {
+ assert(begin != NULL);
+ assert(loc_next >= 0);
+ assert(insert_begin != NULL);
+
+ // track currently observed nodes
+ void *dest_prev = NULL;
+ void *dest = *begin;
+ void *src = insert_begin;
+
+ // special case: list is empty
+ if (dest == NULL) {
+ *begin = src;
+ if (end != NULL) {
+ *end = cx_linked_list_last(src, loc_next);
+ }
+ return;
+ }
+
+ // search the list for insertion points
+ while (dest != NULL && src != NULL) {
+ // compare current list node with source node
+ // if less or equal, skip
+ if (cmp_func(dest, src) <= 0) {
+ dest_prev = dest;
+ dest = ll_next(dest);
+ continue;
+ }
+
+ // determine chain of elements that can be inserted
+ void *end_of_chain = src;
+ void *next_in_chain = ll_next(src);
+ while (next_in_chain != NULL) {
+ // once we become larger than the list elem, break
+ if (cmp_func(dest, next_in_chain) <= 0) {
+ break;
+ }
+ // otherwise, we can insert one more
+ end_of_chain = next_in_chain;
+ next_in_chain = ll_next(next_in_chain);
+ }
+
+ // insert the elements
+ if (dest_prev == NULL) {
+ // new begin
+ *begin = src;
+ } else {
+ cx_linked_list_link(dest_prev, src, loc_prev, loc_next);
+ }
+ cx_linked_list_link(end_of_chain, dest, loc_prev, loc_next);
+
+ // continue with next
+ src = next_in_chain;
+ dest_prev = dest;
+ dest = ll_next(dest);
+ }
+
+ // insert remaining items
+ if (src != NULL) {
+ cx_linked_list_link(dest_prev, src, loc_prev, loc_next);
+ }
+
+ // determine new end of list, if requested
+ if (end != NULL) {
+ *end = cx_linked_list_last(
+ dest != NULL ? dest : dest_prev, loc_next);
+ }
+}
+
+void cx_linked_list_remove(
+ void **begin,
+ void **end,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next,
+ void *node
+) {
+ assert(node != NULL);
+ assert(loc_next >= 0);
+ assert(loc_prev >= 0 || begin != NULL);
+
+ // find adjacent nodes
+ void *next = ll_next(node);
+ void *prev;
+ if (loc_prev >= 0) {
+ prev = ll_prev(node);
+ } else {
+ prev = cx_linked_list_prev(*begin, loc_next, node);
+ }
+
+ // update next pointer of prev node, or set begin
+ if (prev == NULL) {
+ if (begin != NULL) {
+ *begin = next;
+ }
+ } else {
+ ll_next(prev) = next;
+ }
+
+ // update prev pointer of next node, or set end
+ if (next == NULL) {
+ if (end != NULL) {
+ *end = prev;
+ }
+ } else if (loc_prev >= 0) {
+ ll_prev(next) = prev;
+ }
+}
+
+size_t cx_linked_list_size(
+ const void *node,
+ ptrdiff_t loc_next
+) {
+ assert(loc_next >= 0);
+ size_t size = 0;
+ while (node != NULL) {
+ node = ll_next(node);
+ size++;
+ }
+ return size;
+}
+
+#ifndef CX_LINKED_LIST_SORT_SBO_SIZE
+#define CX_LINKED_LIST_SORT_SBO_SIZE 1024
+#endif
+
+static void cx_linked_list_sort_merge(
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next,
+ ptrdiff_t loc_data,
+ size_t length,
+ void *ls,
+ void *le,
+ void *re,
+ cx_compare_func cmp_func,
+ void **begin,
+ void **end
+) {
+ void *sbo[CX_LINKED_LIST_SORT_SBO_SIZE];
+ void **sorted = length >= CX_LINKED_LIST_SORT_SBO_SIZE ?
+ malloc(sizeof(void *) * length) : sbo;
+ if (sorted == NULL) abort();
+ void *rc, *lc;
+
+ lc = ls;
+ rc = le;
+ size_t n = 0;
+ while (lc && lc != le && rc != re) {
+ if (cmp_func(ll_data(lc), ll_data(rc)) <= 0) {
+ sorted[n] = lc;
+ lc = ll_next(lc);
+ } else {
+ sorted[n] = rc;
+ rc = ll_next(rc);
+ }
+ n++;
+ }
+ while (lc && lc != le) {
+ sorted[n] = lc;
+ lc = ll_next(lc);
+ n++;
+ }
+ while (rc && rc != re) {
+ sorted[n] = rc;
+ rc = ll_next(rc);
+ n++;
+ }
+
+ // Update pointer
+ if (loc_prev >= 0) ll_prev(sorted[0]) = NULL;
+ cx_for_n (i, length - 1) {
+ cx_linked_list_link(sorted[i], sorted[i + 1], loc_prev, loc_next);
+ }
+ ll_next(sorted[length - 1]) = NULL;
+
+ *begin = sorted[0];
+ *end = sorted[length-1];
+ if (sorted != sbo) {
+ free(sorted);
+ }
+}
+
+void cx_linked_list_sort( // NOLINT(misc-no-recursion) - purposely recursive function
+ void **begin,
+ void **end,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next,
+ ptrdiff_t loc_data,
+ cx_compare_func cmp_func
+) {
+ assert(begin != NULL);
+ assert(loc_next >= 0);
+ assert(loc_data >= 0);
+ assert(cmp_func);
+
+ void *lc, *ls, *le, *re;
+
+ // set start node
+ ls = *begin;
+
+ // early exit when this list is empty
+ if (ls == NULL) return;
+
+ // check how many elements are already sorted
+ lc = ls;
+ size_t ln = 1;
+ while (ll_next(lc) != NULL && cmp_func(ll_data(ll_next(lc)), ll_data(lc)) > 0) {
+ lc = ll_next(lc);
+ ln++;
+ }
+ le = ll_next(lc);
+
+ // if first unsorted node is NULL, the list is already completely sorted
+ if (le != NULL) {
+ void *rc;
+ size_t rn = 1;
+ rc = le;
+ // skip already sorted elements
+ while (ll_next(rc) != NULL && cmp_func(ll_data(ll_next(rc)), ll_data(rc)) > 0) {
+ rc = ll_next(rc);
+ rn++;
+ }
+ re = ll_next(rc);
+
+ // {ls,...,le->prev} and {rs,...,re->prev} are sorted - merge them
+ void *sorted_begin, *sorted_end;
+ cx_linked_list_sort_merge(loc_prev, loc_next, loc_data,
+ ln + rn, ls, le, re, cmp_func,
+ &sorted_begin, &sorted_end);
+
+ // Something left? Sort it!
+ size_t remainder_length = cx_linked_list_size(re, loc_next);
+ if (remainder_length > 0) {
+ void *remainder = re;
+ cx_linked_list_sort(&remainder, NULL, loc_prev, loc_next, loc_data, cmp_func);
+
+ // merge sorted list with (also sorted) remainder
+ cx_linked_list_sort_merge(loc_prev, loc_next, loc_data,
+ ln + rn + remainder_length,
+ sorted_begin, remainder, NULL, cmp_func,
+ &sorted_begin, &sorted_end);
+ }
+ *begin = sorted_begin;
+ if (end) *end = sorted_end;
+ }
+}
+
+int cx_linked_list_compare(
+ const void *begin_left,
+ const void *begin_right,
+ ptrdiff_t loc_advance,
+ ptrdiff_t loc_data,
+ cx_compare_func cmp_func
+) {
+ const void *left = begin_left, *right = begin_right;
+
+ while (left != NULL && right != NULL) {
+ const void *left_data = ll_data(left);
+ const void *right_data = ll_data(right);
+ int result = cmp_func(left_data, right_data);
+ if (result != 0) return result;
+ left = ll_advance(left);
+ right = ll_advance(right);
+ }
+
+ if (left != NULL) { return 1; }
+ else if (right != NULL) { return -1; }
+ else { return 0; }
+}
+
+void cx_linked_list_reverse(
+ void **begin,
+ void **end,
+ ptrdiff_t loc_prev,
+ ptrdiff_t loc_next
+) {
+ assert(begin != NULL);
+ assert(loc_next >= 0);
+
+ // swap all links
+ void *prev = NULL;
+ void *cur = *begin;
+ while (cur != NULL) {
+ void *next = ll_next(cur);
+
+ ll_next(cur) = prev;
+ if (loc_prev >= 0) {
+ ll_prev(cur) = next;
+ }
+
+ prev = cur;
+ cur = next;
+ }
+
+ // update begin and end
+ if (end != NULL) {
+ *end = *begin;
+ }
+ *begin = prev;
+}
+
+// HIGH LEVEL LINKED LIST IMPLEMENTATION
+
+typedef struct cx_linked_list_node cx_linked_list_node;
+struct cx_linked_list_node {
+ cx_linked_list_node *prev;
+ cx_linked_list_node *next;
+ char payload[];
+};
+
+#define CX_LL_LOC_PREV offsetof(cx_linked_list_node, prev)
+#define CX_LL_LOC_NEXT offsetof(cx_linked_list_node, next)
+#define CX_LL_LOC_DATA offsetof(cx_linked_list_node, payload)
+
+typedef struct {
+ struct cx_list_s base;
+ cx_linked_list_node *begin;
+ cx_linked_list_node *end;
+} cx_linked_list;
+
+static cx_linked_list_node *cx_ll_node_at(
+ const cx_linked_list *list,
+ size_t index
+) {
+ if (index >= list->base.collection.size) {
+ return NULL;
+ } else if (index > list->base.collection.size / 2) {
+ return cx_linked_list_at(list->end, list->base.collection.size - 1, CX_LL_LOC_PREV, index);
+ } else {
+ return cx_linked_list_at(list->begin, 0, CX_LL_LOC_NEXT, index);
+ }
+}
+
+static cx_linked_list_node *cx_ll_malloc_node(const struct cx_list_s *list) {
+ return cxMalloc(list->collection.allocator,
+ sizeof(cx_linked_list_node) + list->collection.elem_size);
+}
+
+static int cx_ll_insert_at(
+ struct cx_list_s *list,
+ cx_linked_list_node *node,
+ const void *elem
+) {
+
+ // create the new new_node
+ cx_linked_list_node *new_node = cx_ll_malloc_node(list);
+
+ // sortir if failed
+ if (new_node == NULL) return 1;
+
+ // initialize new new_node
+ new_node->prev = new_node->next = NULL;
+ memcpy(new_node->payload, elem, list->collection.elem_size);
+
+ // insert
+ cx_linked_list *ll = (cx_linked_list *) list;
+ cx_linked_list_insert_chain(
+ (void **) &ll->begin, (void **) &ll->end,
+ CX_LL_LOC_PREV, CX_LL_LOC_NEXT,
+ node, new_node, new_node
+ );
+
+ // increase the size and return
+ list->collection.size++;
+ return 0;
+}
+
+static size_t cx_ll_insert_array(
+ struct cx_list_s *list,
+ size_t index,
+ const void *array,
+ size_t n
+) {
+ // out-of bounds and corner case check
+ if (index > list->collection.size || n == 0) return 0;
+
+ // find position efficiently
+ cx_linked_list_node *node = index == 0 ? NULL : cx_ll_node_at((cx_linked_list *) list, index - 1);
+
+ // perform first insert
+ if (0 != cx_ll_insert_at(list, node, array)) {
+ return 1;
+ }
+
+ // is there more?
+ if (n == 1) return 1;
+
+ // we now know exactly where we are
+ node = node == NULL ? ((cx_linked_list *) list)->begin : node->next;
+
+ // we can add the remaining nodes and immediately advance to the inserted node
+ const char *source = array;
+ for (size_t i = 1; i < n; i++) {
+ source += list->collection.elem_size;
+ if (0 != cx_ll_insert_at(list, node, source)) {
+ return i;
+ }
+ node = node->next;
+ }
+ return n;
+}
+
+static int cx_ll_insert_element(
+ struct cx_list_s *list,
+ size_t index,
+ const void *element
+) {
+ return 1 != cx_ll_insert_array(list, index, element, 1);
+}
+
+static _Thread_local cx_compare_func cx_ll_insert_sorted_cmp_func;
+
+static int cx_ll_insert_sorted_cmp_helper(const void *l, const void *r) {
+ const cx_linked_list_node *left = l;
+ const cx_linked_list_node *right = r;
+ return cx_ll_insert_sorted_cmp_func(left->payload, right->payload);
+}
+
+static size_t cx_ll_insert_sorted(
+ struct cx_list_s *list,
+ const void *array,
+ size_t n
+) {
+ // special case
+ if (n == 0) return 0;
+
+ // create a new chain of nodes
+ cx_linked_list_node *chain = cx_ll_malloc_node(list);
+ if (chain == NULL) return 0;
+
+ memcpy(chain->payload, array, list->collection.elem_size);
+ chain->prev = NULL;
+ chain->next = NULL;
+
+ // add all elements from the array to that chain
+ cx_linked_list_node *prev = chain;
+ const char *src = array;
+ size_t inserted = 1;
+ for (; inserted < n; inserted++) {
+ cx_linked_list_node *next = cx_ll_malloc_node(list);
+ if (next == NULL) break;
+ src += list->collection.elem_size;
+ memcpy(next->payload, src, list->collection.elem_size);
+ prev->next = next;
+ next->prev = prev;
+ prev = next;
+ }
+ prev->next = NULL;
+
+ // invoke the low level function
+ cx_linked_list *ll = (cx_linked_list *) list;
+ cx_ll_insert_sorted_cmp_func = list->collection.cmpfunc;
+ cx_linked_list_insert_sorted_chain(
+ (void **) &ll->begin,
+ (void **) &ll->end,
+ CX_LL_LOC_PREV,
+ CX_LL_LOC_NEXT,
+ chain,
+ cx_ll_insert_sorted_cmp_helper
+ );
+
+ // adjust the list metadata
+ list->collection.size += inserted;
+
+ return inserted;
+}
+
+static int cx_ll_remove(
+ struct cx_list_s *list,
+ size_t index
+) {
+ cx_linked_list *ll = (cx_linked_list *) list;
+ cx_linked_list_node *node = cx_ll_node_at(ll, index);
+
+ // out-of-bounds check
+ if (node == NULL) return 1;
+
+ // element destruction
+ cx_invoke_destructor(list, node->payload);
+
+ // remove
+ cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end,
+ CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node);
+
+ // adjust size
+ list->collection.size--;
+
+ // free and return
+ cxFree(list->collection.allocator, node);
+
+ return 0;
+}
+
+static void cx_ll_clear(struct cx_list_s *list) {
+ if (list->collection.size == 0) return;
+
+ cx_linked_list *ll = (cx_linked_list *) list;
+ cx_linked_list_node *node = ll->begin;
+ while (node != NULL) {
+ cx_invoke_destructor(list, node->payload);
+ cx_linked_list_node *next = node->next;
+ cxFree(list->collection.allocator, node);
+ node = next;
+ }
+ ll->begin = ll->end = NULL;
+ list->collection.size = 0;
+}
+
+#ifndef CX_LINKED_LIST_SWAP_SBO_SIZE
+#define CX_LINKED_LIST_SWAP_SBO_SIZE 128
+#endif
+unsigned cx_linked_list_swap_sbo_size = CX_LINKED_LIST_SWAP_SBO_SIZE;
+
+static int cx_ll_swap(
+ struct cx_list_s *list,
+ size_t i,
+ size_t j
+) {
+ if (i >= list->collection.size || j >= list->collection.size) return 1;
+ if (i == j) return 0;
+
+ // perform an optimized search that finds both elements in one run
+ cx_linked_list *ll = (cx_linked_list *) list;
+ size_t mid = list->collection.size / 2;
+ size_t left, right;
+ if (i < j) {
+ left = i;
+ right = j;
+ } else {
+ left = j;
+ right = i;
+ }
+ cx_linked_list_node *nleft, *nright;
+ if (left < mid && right < mid) {
+ // case 1: both items left from mid
+ nleft = cx_ll_node_at(ll, left);
+ assert(nleft != NULL);
+ nright = nleft;
+ for (size_t c = left; c < right; c++) {
+ nright = nright->next;
+ }
+ } else if (left >= mid && right >= mid) {
+ // case 2: both items right from mid
+ nright = cx_ll_node_at(ll, right);
+ assert(nright != NULL);
+ nleft = nright;
+ for (size_t c = right; c > left; c--) {
+ nleft = nleft->prev;
+ }
+ } else {
+ // case 3: one item left, one item right
+
+ // chose the closest to begin / end
+ size_t closest;
+ size_t other;
+ size_t diff2boundary = list->collection.size - right - 1;
+ if (left <= diff2boundary) {
+ closest = left;
+ other = right;
+ nleft = cx_ll_node_at(ll, left);
+ } else {
+ closest = right;
+ other = left;
+ diff2boundary = left;
+ nright = cx_ll_node_at(ll, right);
+ }
+
+ // is other element closer to us or closer to boundary?
+ if (right - left <= diff2boundary) {
+ // search other element starting from already found element
+ if (closest == left) {
+ nright = nleft;
+ for (size_t c = left; c < right; c++) {
+ nright = nright->next;
+ }
+ } else {
+ nleft = nright;
+ for (size_t c = right; c > left; c--) {
+ nleft = nleft->prev;
+ }
+ }
+ } else {
+ // search other element starting at the boundary
+ if (closest == left) {
+ nright = cx_ll_node_at(ll, other);
+ } else {
+ nleft = cx_ll_node_at(ll, other);
+ }
+ }
+ }
+
+ if (list->collection.elem_size > CX_LINKED_LIST_SWAP_SBO_SIZE) {
+ cx_linked_list_node *prev = nleft->prev;
+ cx_linked_list_node *next = nright->next;
+ cx_linked_list_node *midstart = nleft->next;
+ cx_linked_list_node *midend = nright->prev;
+
+ if (prev == NULL) {
+ ll->begin = nright;
+ } else {
+ prev->next = nright;
+ }
+ nright->prev = prev;
+ if (midstart == nright) {
+ // special case: both nodes are adjacent
+ nright->next = nleft;
+ nleft->prev = nright;
+ } else {
+ // likely case: a chain is between the two nodes
+ nright->next = midstart;
+ midstart->prev = nright;
+ midend->next = nleft;
+ nleft->prev = midend;
+ }
+ nleft->next = next;
+ if (next == NULL) {
+ ll->end = nleft;
+ } else {
+ next->prev = nleft;
+ }
+ } else {
+ // swap payloads to avoid relinking
+ char buf[CX_LINKED_LIST_SWAP_SBO_SIZE];
+ memcpy(buf, nleft->payload, list->collection.elem_size);
+ memcpy(nleft->payload, nright->payload, list->collection.elem_size);
+ memcpy(nright->payload, buf, list->collection.elem_size);
+ }
+
+ return 0;
+}
+
+static void *cx_ll_at(
+ const struct cx_list_s *list,
+ size_t index
+) {
+ cx_linked_list *ll = (cx_linked_list *) list;
+ cx_linked_list_node *node = cx_ll_node_at(ll, index);
+ return node == NULL ? NULL : node->payload;
+}
+
+static ssize_t cx_ll_find_remove(
+ struct cx_list_s *list,
+ const void *elem,
+ bool remove
+) {
+ if (remove) {
+ cx_linked_list *ll = ((cx_linked_list *) list);
+ cx_linked_list_node *node;
+ ssize_t index = cx_linked_list_find_node(
+ (void **) &node,
+ ll->begin,
+ CX_LL_LOC_NEXT, CX_LL_LOC_DATA,
+ list->collection.cmpfunc, elem
+ );
+ if (node != NULL) {
+ cx_invoke_destructor(list, node->payload);
+ cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end,
+ CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node);
+ list->collection.size--;
+ cxFree(list->collection.allocator, node);
+ }
+ return index;
+ } else {
+ return cx_linked_list_find(
+ ((cx_linked_list *) list)->begin,
+ CX_LL_LOC_NEXT, CX_LL_LOC_DATA,
+ list->collection.cmpfunc, elem
+ );
+ }
+}
+
+static void cx_ll_sort(struct cx_list_s *list) {
+ cx_linked_list *ll = (cx_linked_list *) list;
+ cx_linked_list_sort((void **) &ll->begin, (void **) &ll->end,
+ CX_LL_LOC_PREV, CX_LL_LOC_NEXT, CX_LL_LOC_DATA,
+ list->collection.cmpfunc);
+}
+
+static void cx_ll_reverse(struct cx_list_s *list) {
+ cx_linked_list *ll = (cx_linked_list *) list;
+ cx_linked_list_reverse((void **) &ll->begin, (void **) &ll->end, CX_LL_LOC_PREV, CX_LL_LOC_NEXT);
+}
+
+static int cx_ll_compare(
+ const struct cx_list_s *list,
+ const struct cx_list_s *other
+) {
+ cx_linked_list *left = (cx_linked_list *) list;
+ cx_linked_list *right = (cx_linked_list *) other;
+ return cx_linked_list_compare(left->begin, right->begin,
+ CX_LL_LOC_NEXT, CX_LL_LOC_DATA,
+ list->collection.cmpfunc);
+}
+
+static bool cx_ll_iter_valid(const void *it) {
+ const struct cx_iterator_s *iter = it;
+ return iter->elem_handle != NULL;
+}
+
+static void cx_ll_iter_next(void *it) {
+ struct cx_iterator_s *iter = it;
+ if (iter->base.remove) {
+ iter->base.remove = false;
+ struct cx_list_s *list = iter->src_handle.m;
+ cx_linked_list *ll = iter->src_handle.m;
+ cx_linked_list_node *node = iter->elem_handle;
+ iter->elem_handle = node->next;
+ cx_invoke_destructor(list, node->payload);
+ cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end,
+ CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node);
+ list->collection.size--;
+ cxFree(list->collection.allocator, node);
+ } else {
+ iter->index++;
+ cx_linked_list_node *node = iter->elem_handle;
+ iter->elem_handle = node->next;
+ }
+}
+
+static void cx_ll_iter_prev(void *it) {
+ struct cx_iterator_s *iter = it;
+ if (iter->base.remove) {
+ iter->base.remove = false;
+ struct cx_list_s *list = iter->src_handle.m;
+ cx_linked_list *ll = iter->src_handle.m;
+ cx_linked_list_node *node = iter->elem_handle;
+ iter->elem_handle = node->prev;
+ iter->index--;
+ cx_invoke_destructor(list, node->payload);
+ cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end,
+ CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node);
+ list->collection.size--;
+ cxFree(list->collection.allocator, node);
+ } else {
+ iter->index--;
+ cx_linked_list_node *node = iter->elem_handle;
+ iter->elem_handle = node->prev;
+ }
+}
+
+static void *cx_ll_iter_current(const void *it) {
+ const struct cx_iterator_s *iter = it;
+ cx_linked_list_node *node = iter->elem_handle;
+ return node->payload;
+}
+
+static CxIterator cx_ll_iterator(
+ const struct cx_list_s *list,
+ size_t index,
+ bool backwards
+) {
+ CxIterator iter;
+ iter.index = index;
+ iter.src_handle.c = list;
+ iter.elem_handle = cx_ll_node_at((const cx_linked_list *) list, index);
+ iter.elem_size = list->collection.elem_size;
+ iter.elem_count = list->collection.size;
+ iter.base.valid = cx_ll_iter_valid;
+ iter.base.current = cx_ll_iter_current;
+ iter.base.next = backwards ? cx_ll_iter_prev : cx_ll_iter_next;
+ iter.base.mutating = false;
+ iter.base.remove = false;
+ return iter;
+}
+
+static int cx_ll_insert_iter(
+ CxIterator *iter,
+ const void *elem,
+ int prepend
+) {
+ struct cx_list_s *list = iter->src_handle.m;
+ cx_linked_list_node *node = iter->elem_handle;
+ if (node != NULL) {
+ assert(prepend >= 0 && prepend <= 1);
+ cx_linked_list_node *choice[2] = {node, node->prev};
+ int result = cx_ll_insert_at(list, choice[prepend], elem);
+ if (result == 0) {
+ iter->elem_count++;
+ if (prepend) {
+ iter->index++;
+ }
+ }
+ return result;
+ } else {
+ int result = cx_ll_insert_element(list, list->collection.size, elem);
+ if (result == 0) {
+ iter->elem_count++;
+ iter->index = list->collection.size;
+ }
+ return result;
+ }
+}
+
+static void cx_ll_destructor(CxList *list) {
+ cx_linked_list *ll = (cx_linked_list *) list;
+
+ cx_linked_list_node *node = ll->begin;
+ while (node) {
+ cx_invoke_destructor(list, node->payload);
+ void *next = node->next;
+ cxFree(list->collection.allocator, node);
+ node = next;
+ }
+
+ cxFree(list->collection.allocator, list);
+}
+
+static cx_list_class cx_linked_list_class = {
+ cx_ll_destructor,
+ cx_ll_insert_element,
+ cx_ll_insert_array,
+ cx_ll_insert_sorted,
+ cx_ll_insert_iter,
+ cx_ll_remove,
+ cx_ll_clear,
+ cx_ll_swap,
+ cx_ll_at,
+ cx_ll_find_remove,
+ cx_ll_sort,
+ cx_ll_compare,
+ cx_ll_reverse,
+ cx_ll_iterator,
+};
+
+CxList *cxLinkedListCreate(
+ const CxAllocator *allocator,
+ cx_compare_func comparator,
+ size_t elem_size
+) {
+ if (allocator == NULL) {
+ allocator = cxDefaultAllocator;
+ }
+
+ cx_linked_list *list = cxCalloc(allocator, 1, sizeof(cx_linked_list));
+ if (list == NULL) return NULL;
+
+ list->base.cl = &cx_linked_list_class;
+ list->base.collection.allocator = allocator;
+
+ if (elem_size > 0) {
+ list->base.collection.elem_size = elem_size;
+ list->base.collection.cmpfunc = comparator;
+ } else {
+ list->base.collection.cmpfunc = comparator == NULL ? cx_cmp_ptr : comparator;
+ cxListStorePointers((CxList *) list);
+ }
+
+ return (CxList *) list;
+}