src/ucx/linked_list.c

changeset 415
d938228c382e
child 438
22eca559aded
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/ucx/linked_list.c	Sun Nov 06 15:53:32 2022 +0100
@@ -0,0 +1,807 @@
+/*
+ * 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 <stdint.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_f(node, follow_ptr) ((follow_ptr)?CX_LL_PTR(node, loc_data):(((char*)(node))+loc_data))
+#define ll_data(node) ll_data_f(node,follow_ptr)
+
+void *cx_linked_list_at(
+        void const *start,
+        size_t start_index,
+        ptrdiff_t loc_advance,
+        size_t index
+) {
+    assert(start != NULL);
+    assert(loc_advance >= 0);
+    size_t i = start_index;
+    void const *cur = start;
+    while (i != index && cur != NULL) {
+        cur = ll_advance(cur);
+        i < index ? i++ : i--;
+    }
+    return (void *) cur;
+}
+
+size_t cx_linked_list_find(
+        void const *start,
+        ptrdiff_t loc_advance,
+        ptrdiff_t loc_data,
+        bool follow_ptr,
+        CxListComparator cmp_func,
+        void const *elem
+) {
+    assert(start != NULL);
+    assert(loc_advance >= 0);
+    assert(loc_data >= 0);
+    assert(cmp_func);
+
+    void const *node = start;
+    size_t index = 0;
+    do {
+        void *current = ll_data(node);
+        if (cmp_func(current, elem) == 0) {
+            return index;
+        }
+        node = ll_advance(node);
+        index++;
+    } while (node != NULL);
+    return index;
+}
+
+void *cx_linked_list_first(
+        void const *node,
+        ptrdiff_t loc_prev
+) {
+    return cx_linked_list_last(node, loc_prev);
+}
+
+void *cx_linked_list_last(
+        void const *node,
+        ptrdiff_t loc_next
+) {
+    assert(node != NULL);
+    assert(loc_next >= 0);
+
+    void const *cur = node;
+    void const *last;
+    do {
+        last = cur;
+    } while ((cur = ll_next(cur)) != NULL);
+
+    return (void *) last;
+}
+
+void *cx_linked_list_prev(
+        void const *begin,
+        ptrdiff_t loc_next,
+        void const *node
+) {
+    assert(begin != NULL);
+    assert(node != NULL);
+    assert(loc_next >= 0);
+    if (begin == node) return NULL;
+    void const *cur = begin;
+    void const *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_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(
+        void const *node,
+        ptrdiff_t loc_next
+) {
+    assert(loc_next >= 0);
+    size_t size = 0;
+    while (node != NULL) {
+        node = ll_next(node);
+        size++;
+    }
+    return size;
+}
+
+static void *cx_linked_list_sort_merge(
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next,
+        ptrdiff_t loc_data,
+        bool follow_ptr,
+        size_t length,
+        void *ls,
+        void *le,
+        void *re,
+        CxListComparator cmp_func
+) {
+    const size_t sbo_len = 1024;
+    void *sbo[sbo_len];
+    void **sorted = (length >= sbo_len) ? 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;
+
+    void *ret = sorted[0];
+    if (sorted != sbo) {
+        free(sorted);
+    }
+    return ret;
+}
+
+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,
+        bool follow_ptr,
+        CxListComparator 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;
+
+    // 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 = cx_linked_list_sort_merge(loc_prev, loc_next, loc_data, follow_ptr,
+                                                 ln + rn, ls, le, re, cmp_func);
+
+        // 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, follow_ptr, cmp_func);
+
+            // merge sorted list with (also sorted) remainder
+            *begin = cx_linked_list_sort_merge(loc_prev, loc_next, loc_data, follow_ptr,
+                                               ln + rn + remainder_length,
+                                               sorted, remainder, NULL, cmp_func);
+        } else {
+            // no remainder - we've got our sorted list
+            *begin = sorted;
+        }
+        if (end) *end = cx_linked_list_last(sorted, loc_next);
+    }
+}
+
+int cx_linked_list_compare(
+        void const *begin_left,
+        void const *begin_right,
+        ptrdiff_t loc_advance,
+        ptrdiff_t loc_data,
+        bool follow_ptr_left,
+        bool follow_ptr_right,
+        CxListComparator cmp_func
+) {
+    void const *left = begin_left, *right = begin_right;
+
+    while (left != NULL && right != NULL) {
+        void const *left_data = ll_data_f(left, follow_ptr_left);
+        void const *right_data = ll_data_f(right, follow_ptr_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;
+    bool follow_ptr;
+} cx_linked_list;
+
+static cx_linked_list_node *cx_ll_node_at(
+        cx_linked_list const *list,
+        size_t index
+) {
+    if (index >= list->base.size) {
+        return NULL;
+    } else if (index > list->base.size / 2) {
+        return cx_linked_list_at(list->end, list->base.size - 1, CX_LL_LOC_PREV, index);
+    } else {
+        return cx_linked_list_at(list->begin, 0, CX_LL_LOC_NEXT, index);
+    }
+}
+
+static int cx_ll_insert_at(
+        struct cx_list_s *list,
+        cx_linked_list_node *node,
+        void const *elem
+) {
+
+    // create the new new_node
+    cx_linked_list_node *new_node = cxMalloc(list->allocator,
+                                             sizeof(cx_linked_list_node) + list->itemsize);
+
+    // 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->itemsize);
+
+    // 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->size++;
+    return 0;
+}
+
+static int cx_ll_insert(
+        struct cx_list_s *list,
+        size_t index,
+        void const *elem
+) {
+    // out-of bounds check
+    if (index > list->size) return 1;
+
+    // find position efficiently
+    cx_linked_list_node *node = index == 0 ? NULL : cx_ll_node_at((cx_linked_list *) list, index - 1);
+
+    // perform insert
+    return cx_ll_insert_at(list, node, elem);
+}
+
+static int cx_ll_add(
+        struct cx_list_s *list,
+        void const *elem
+) {
+    return cx_ll_insert(list, list->size, elem);
+}
+
+static int cx_pll_insert(
+        struct cx_list_s *list,
+        size_t index,
+        void const *elem
+) {
+    return cx_ll_insert(list, index, &elem);
+}
+
+static int cx_pll_add(
+        struct cx_list_s *list,
+        void const *elem
+) {
+    return cx_ll_insert(list, list->size, &elem);
+}
+
+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;
+
+    // remove
+    cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end,
+                          CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node);
+
+    // adjust size
+    list->size--;
+
+    // free and return
+    cxFree(list->allocator, node);
+
+    return 0;
+}
+
+static void *cx_ll_at(
+        struct cx_list_s const *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 void *cx_pll_at(
+        struct cx_list_s const *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 : *(void **) node->payload;
+}
+
+static size_t cx_ll_find(
+        struct cx_list_s const *list,
+        void const *elem
+) {
+    cx_linked_list *ll = (cx_linked_list *) list;
+    return cx_linked_list_find(((cx_linked_list *) list)->begin,
+                               CX_LL_LOC_NEXT, CX_LL_LOC_DATA,
+                               ll->follow_ptr, list->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,
+                        ll->follow_ptr, list->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(
+        struct cx_list_s const *list,
+        struct cx_list_s const *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,
+                                  left->follow_ptr, right->follow_ptr, list->cmpfunc);
+}
+
+static bool cx_ll_iter_valid(CxIterator const *iter) {
+    return iter->elem_handle != NULL;
+}
+
+static void cx_ll_iter_next(CxIterator *iter) {
+    if (iter->remove) {
+        iter->remove = false;
+        cx_linked_list *ll = iter->src_handle;
+        cx_linked_list_node *node = iter->elem_handle;
+        iter->elem_handle = node->next;
+        cx_linked_list_remove((void **) &ll->begin, (void **) &ll->end,
+                              CX_LL_LOC_PREV, CX_LL_LOC_NEXT, node);
+        ll->base.size--;
+        cxFree(ll->base.allocator, node);
+    } else {
+        iter->index++;
+        cx_linked_list_node *node = iter->elem_handle;
+        iter->elem_handle = node->next;
+    }
+}
+
+static void *cx_ll_iter_current(CxIterator const *iter) {
+    cx_linked_list_node *node = iter->elem_handle;
+    return node->payload;
+}
+
+static void *cx_pll_iter_current(CxIterator const *iter) {
+    cx_linked_list_node *node = iter->elem_handle;
+    return *(void **) node->payload;
+}
+
+static CxIterator cx_ll_iterator(
+        struct cx_list_s *list,
+        size_t index
+) {
+    CxIterator iter;
+    iter.index = index;
+    iter.src_handle = list;
+    iter.elem_handle = cx_ll_node_at((cx_linked_list const *) list, index);
+    iter.valid = cx_ll_iter_valid;
+    iter.current = cx_ll_iter_current;
+    iter.next = cx_ll_iter_next;
+    iter.remove = false;
+    return iter;
+}
+
+static CxIterator cx_pll_iterator(
+        struct cx_list_s *list,
+        size_t index
+) {
+    CxIterator iter = cx_ll_iterator(list, index);
+    iter.current = cx_pll_iter_current;
+    return iter;
+}
+
+static int cx_ll_insert_iter(
+        CxIterator *iter,
+        void const *elem,
+        int prepend
+) {
+    struct cx_list_s *list = iter->src_handle;
+    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);
+        iter->index += prepend * (0 == result);
+        return result;
+    } else {
+        int result = cx_ll_insert(list, list->size, elem);
+        iter->index = list->size;
+        return result;
+    }
+}
+
+static int cx_pll_insert_iter(
+        CxIterator *iter,
+        void const *elem,
+        int prepend
+) {
+    return cx_ll_insert_iter(iter, &elem, prepend);
+}
+
+static void cx_ll_destructor(CxList *list) {
+    cx_linked_list *ll = (cx_linked_list *) list;
+
+    cx_linked_list_node *node = ll->begin;
+    while (node) {
+        void *next = node->next;
+        cxFree(list->allocator, node);
+        node = next;
+    }
+    // do not free the list pointer, this is just a destructor!
+}
+
+static cx_list_class cx_linked_list_class = {
+        cx_ll_destructor,
+        cx_ll_add,
+        cx_ll_insert,
+        cx_ll_insert_iter,
+        cx_ll_remove,
+        cx_ll_at,
+        cx_ll_find,
+        cx_ll_sort,
+        cx_ll_compare,
+        cx_ll_reverse,
+        cx_ll_iterator
+};
+
+static cx_list_class cx_pointer_linked_list_class = {
+        cx_ll_destructor,
+        cx_pll_add,
+        cx_pll_insert,
+        cx_pll_insert_iter,
+        cx_ll_remove,
+        cx_pll_at,
+        cx_ll_find,
+        cx_ll_sort,
+        cx_ll_compare,
+        cx_ll_reverse,
+        cx_pll_iterator,
+};
+
+CxList *cxLinkedListCreate(
+        CxAllocator const *allocator,
+        CxListComparator comparator,
+        size_t item_size
+) {
+    cx_linked_list *list = cxCalloc(allocator, 1, sizeof(cx_linked_list));
+    if (list == NULL) return NULL;
+
+    list->follow_ptr = false;
+    list->base.cl = &cx_linked_list_class;
+    list->base.allocator = allocator;
+    list->base.cmpfunc = comparator;
+    list->base.itemsize = item_size;
+    list->base.capacity = SIZE_MAX;
+
+    return (CxList *) list;
+}
+
+CxList *cxPointerLinkedListCreate(
+        CxAllocator const *allocator,
+        CxListComparator comparator
+) {
+    cx_linked_list *list = cxCalloc(allocator, 1, sizeof(cx_linked_list));
+    if (list == NULL) return NULL;
+
+    list->follow_ptr = true;
+    list->base.cl = &cx_pointer_linked_list_class;
+    list->base.allocator = allocator;
+    list->base.cmpfunc = comparator;
+    list->base.itemsize = sizeof(void *);
+    list->base.capacity = SIZE_MAX;
+
+    return (CxList *) list;
+}
+
+CxList *cxLinkedListFromArray(
+        CxAllocator const *allocator,
+        CxListComparator comparator,
+        size_t item_size,
+        size_t num_items,
+        void const *array
+) {
+    CxList *list = cxLinkedListCreate(allocator, comparator, item_size);
+    if (list == NULL) return NULL;
+    cx_for_n (i, num_items) {
+        if (0 != cxListAdd(list, ((const unsigned char *) array) + i * item_size)) {
+            cx_ll_destructor(list);
+            cxFree(allocator, list);
+            return NULL;
+        }
+    }
+    return list;
+}

mercurial