diff -r e79a60b3a7cb -r 7c3ff86ee9d4 ucx/cx/linked_list.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ucx/cx/linked_list.h	Tue May 23 11:11:28 2023 +0200
@@ -0,0 +1,415 @@
+/*
+ * 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.
+ */
+/**
+ * \file linked_list.h
+ * \brief Linked list implementation.
+ * \details Also provides several low-level functions for custom linked list implementations.
+ * \author Mike Becker
+ * \author Olaf Wintermann
+ * \version 3.0
+ * \copyright 2-Clause BSD License
+ */
+
+#ifndef UCX_LINKED_LIST_H
+#define UCX_LINKED_LIST_H
+
+#include "common.h"
+#include "list.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * Set this flag to true, if you want to disable the use of SBO for
+ * linked list swap operations.
+ */
+extern bool CX_DISABLE_LINKED_LIST_SWAP_SBO;
+
+/**
+ * Allocates a linked list for storing elements with \p item_size bytes each.
+ *
+ * If \p item_size is CX_STORE_POINTERS, the created list will be created as if
+ * cxListStorePointers() was called immediately after creation.
+ *
+ * @param allocator the allocator for allocating the list nodes
+ * (if \c NULL the cxDefaultAllocator will be used)
+ * @param comparator the comparator for the elements
+ * (if \c NULL sort and find functions will not work)
+ * @param item_size the size of each element in bytes
+ * @return the created list
+ */
+CxList *cxLinkedListCreate(
+        CxAllocator const *allocator,
+        cx_compare_func comparator,
+        size_t item_size
+);
+
+/**
+ * Allocates a linked list for storing elements with \p item_size bytes each.
+ *
+ * The list will use cxDefaultAllocator and no comparator function. If you want
+ * to call functions that need a comparator, you must either set one immediately
+ * after list creation or use cxLinkedListCreate().
+ *
+ * If \p item_size is CX_STORE_POINTERS, the created list will be created as if
+ * cxListStorePointers() was called immediately after creation.
+ *
+ * @param item_size the size of each element in bytes
+ * @return the created list
+ */
+#define cxLinkedListCreateSimple(item_size) \
+    cxLinkedListCreate(NULL, NULL, item_size)
+
+/**
+ * Finds the node at a certain index.
+ *
+ * This function can be used to start at an arbitrary position within the list.
+ * If the search index is large than the start index, \p loc_advance must denote
+ * the location of some sort of \c next pointer (i.e. a pointer to the next node).
+ * But it is also possible that the search index is smaller than the start index
+ * (e.g. in cases where traversing a list backwards is faster) in which case
+ * \p loc_advance must denote the location of some sort of \c prev pointer
+ * (i.e. a pointer to the previous node).
+ *
+ * @param start a pointer to the start node
+ * @param start_index the start index
+ * @param loc_advance the location of the pointer to advance
+ * @param index the search index
+ * @return the node found at the specified index
+ */
+void *cx_linked_list_at(
+        void const *start,
+        size_t start_index,
+        ptrdiff_t loc_advance,
+        size_t index
+) __attribute__((__nonnull__));
+
+/**
+ * Finds the index of an element within a linked list.
+ *
+ * @param start a pointer to the start node
+ * @param loc_advance the location of the pointer to advance
+ * @param loc_data the location of the \c data pointer within your node struct
+ * @param cmp_func a compare function to compare \p elem against the node data
+ * @param elem a pointer to the element to find
+ * @return the index of the element or a negative value if it could not be found
+ */
+ssize_t cx_linked_list_find(
+        void const *start,
+        ptrdiff_t loc_advance,
+        ptrdiff_t loc_data,
+        cx_compare_func cmp_func,
+        void const *elem
+) __attribute__((__nonnull__));
+
+/**
+ * Finds the first node in a linked list.
+ *
+ * The function starts with the pointer denoted by \p node and traverses the list
+ * along a prev pointer whose location within the node struct is
+ * denoted by \p loc_prev.
+ *
+ * @param node a pointer to a node in the list
+ * @param loc_prev the location of the \c prev pointer
+ * @return a pointer to the first node
+ */
+void *cx_linked_list_first(
+        void const *node,
+        ptrdiff_t loc_prev
+) __attribute__((__nonnull__));
+
+/**
+ * Finds the last node in a linked list.
+ *
+ * The function starts with the pointer denoted by \p node and traverses the list
+ * along a next pointer whose location within the node struct is
+ * denoted by \p loc_next.
+ *
+ * @param node a pointer to a node in the list
+ * @param loc_next the location of the \c next pointer
+ * @return a pointer to the last node
+ */
+void *cx_linked_list_last(
+        void const *node,
+        ptrdiff_t loc_next
+) __attribute__((__nonnull__));
+
+/**
+ * Finds the predecessor of a node in case it is not linked.
+ *
+ * \remark If \p node is not contained in the list starting with \p begin, the behavior is undefined.
+ *
+ * @param begin the node where to start the search
+ * @param loc_next the location of the \c next pointer
+ * @param node the successor of the node to find
+ * @return the node or \c NULL if \p node has no predecessor
+ */
+void *cx_linked_list_prev(
+        void const *begin,
+        ptrdiff_t loc_next,
+        void const *node
+) __attribute__((__nonnull__));
+
+/**
+ * Adds a new node to a linked list.
+ * The node must not be part of any list already.
+ *
+ * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
+ *
+ * @param begin a pointer to the begin node pointer (if your list has one)
+ * @param end a pointer to the end node pointer (if your list has one)
+ * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
+ * @param loc_next the location of a \c next pointer within your node struct (required)
+ * @param new_node a pointer to the node that shall be appended
+ */
+void cx_linked_list_add(
+        void **begin,
+        void **end,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next,
+        void *new_node
+) __attribute__((__nonnull__(5)));
+
+/**
+ * Prepends a new node to a linked list.
+ * The node must not be part of any list already.
+ *
+ * \remark One of the pointers \p begin or \p end may be \c NULL, but not both.
+ *
+ * @param begin a pointer to the begin node pointer (if your list has one)
+ * @param end a pointer to the end node pointer (if your list has one)
+ * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
+ * @param loc_next the location of a \c next pointer within your node struct (required)
+ * @param new_node a pointer to the node that shall be prepended
+ */
+void cx_linked_list_prepend(
+        void **begin,
+        void **end,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next,
+        void *new_node
+) __attribute__((__nonnull__(5)));
+
+/**
+ * Links two nodes.
+ *
+ * @param left the new predecessor of \p right
+ * @param right the new successor of \p left
+ * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
+ * @param loc_next the location of a \c next pointer within your node struct (required)
+ */
+void cx_linked_list_link(
+        void *left,
+        void *right,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next
+) __attribute__((__nonnull__));
+
+/**
+ * Unlinks two nodes.
+ *
+ * If right is not the successor of left, the behavior is undefined.
+ *
+ * @param left the predecessor of \p right
+ * @param right the successor of \p left
+ * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
+ * @param loc_next the location of a \c next pointer within your node struct (required)
+ */
+void cx_linked_list_unlink(
+        void *left,
+        void *right,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next
+) __attribute__((__nonnull__));
+
+/**
+ * Inserts a new node after a given node of a linked list.
+ * The new node must not be part of any list already.
+ *
+ * \note If you specify \c NULL as the \p node to insert after, this function needs either the \p begin or
+ * the \p end pointer to determine the start of the list. Then the new node will be prepended to the list.
+ *
+ * @param begin a pointer to the begin node pointer (if your list has one)
+ * @param end a pointer to the end node pointer (if your list has one)
+ * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
+ * @param loc_next the location of a \c next pointer within your node struct (required)
+ * @param node the node after which to insert (\c NULL if you want to prepend the node to the list)
+ * @param new_node a pointer to the node that shall be prepended
+ */
+void cx_linked_list_insert(
+        void **begin,
+        void **end,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next,
+        void *node,
+        void *new_node
+) __attribute__((__nonnull__(6)));
+
+/**
+ * Inserts a chain of nodes after a given node of a linked list.
+ * The chain must not be part of any list already.
+ *
+ * If you do not explicitly specify the end of the chain, it will be determined by traversing
+ * the \c next pointer.
+ *
+ * \note If you specify \c NULL as the \p node to insert after, this function needs either the \p begin or
+ * the \p end pointer to determine the start of the list. If only the \p end pointer is specified, you also need
+ * to provide a valid \p loc_prev location.
+ * Then the chain will be prepended to the list.
+ *
+ * @param begin a pointer to the begin node pointer (if your list has one)
+ * @param end a pointer to the end node pointer (if your list has one)
+ * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
+ * @param loc_next the location of a \c next pointer within your node struct (required)
+ * @param node the node after which to insert (\c NULL to prepend the chain to the list)
+ * @param insert_begin a pointer to the first node of the chain that shall be inserted
+ * @param insert_end a pointer to the last node of the chain (or NULL if the last node shall be determined)
+ */
+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
+) __attribute__((__nonnull__(6)));
+
+/**
+ * Removes a node from the linked list.
+ *
+ * If the node to remove is the begin (resp. end) node of the list and if \p begin (resp. \p end)
+ * addresses are provided, the pointers are adjusted accordingly.
+ *
+ * The following combinations of arguments are valid (more arguments are optional):
+ * \li \p loc_next and \p loc_prev (ancestor node is determined by using the prev pointer, overall O(1) performance)
+ * \li \p loc_next and \p begin (ancestor node is determined by list traversal, overall O(n) performance)
+ *
+ * \remark The \c next and \c prev pointers of the removed node are not cleared by this function and may still be used
+ * to traverse to a former adjacent node in the list.
+ *
+ * @param begin a pointer to the begin node pointer (optional)
+ * @param end a pointer to the end node pointer (optional)
+ * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
+ * @param loc_next the location of a \c next pointer within your node struct (required)
+ * @param node the node to remove
+ */
+void cx_linked_list_remove(
+        void **begin,
+        void **end,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next,
+        void *node
+) __attribute__((__nonnull__(5)));
+
+
+/**
+ * Determines the size of a linked list starting with \p node.
+ * @param node the first node
+ * @param loc_next the location of the \c next pointer within the node struct
+ * @return the size of the list or zero if \p node is \c NULL
+ */
+size_t cx_linked_list_size(
+        void const *node,
+        ptrdiff_t loc_next
+);
+
+/**
+ * Sorts a linked list based on a comparison function.
+ *
+ * This function can work with linked lists of the following structure:
+ * \code
+ * typedef struct node node;
+ * struct node {
+ *   node* prev;
+ *   node* next;
+ *   my_payload data;
+ * }
+ * \endcode
+ *
+ * @note This is a recursive function with at most logarithmic recursion depth.
+ *
+ * @param begin a pointer to the begin node pointer (required)
+ * @param end a pointer to the end node pointer (optional)
+ * @param loc_prev the location of a \c prev pointer within your node struct (negative if not present)
+ * @param loc_next the location of a \c next pointer within your node struct (required)
+ * @param loc_data the location of the \c data pointer within your node struct
+ * @param cmp_func the compare function defining the sort order
+ */
+void cx_linked_list_sort(
+        void **begin,
+        void **end,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next,
+        ptrdiff_t loc_data,
+        cx_compare_func cmp_func
+) __attribute__((__nonnull__(1, 6)));
+
+
+/**
+ * Compares two lists element wise.
+ *
+ * \note Both list must have the same structure.
+ *
+ * @param begin_left the begin of the left list (\c NULL denotes an empty list)
+ * @param begin_right the begin of the right list  (\c NULL denotes an empty list)
+ * @param loc_advance the location of the pointer to advance
+ * @param loc_data the location of the \c data pointer within your node struct
+ * @param cmp_func the function to compare the elements
+ * @return the first non-zero result of invoking \p cmp_func or: negative if the left list is smaller than the
+ * right list, positive if the left list is larger than the right list, zero if both lists are equal.
+ */
+int cx_linked_list_compare(
+        void const *begin_left,
+        void const *begin_right,
+        ptrdiff_t loc_advance,
+        ptrdiff_t loc_data,
+        cx_compare_func cmp_func
+) __attribute__((__nonnull__(5)));
+
+/**
+ * Reverses the order of the nodes in a linked list.
+ *
+ * @param begin a pointer to the begin node pointer (required)
+ * @param end a pointer to the end node pointer (optional)
+ * @param loc_prev the location of a \c prev pointer within your node struct (negative if your struct does not have one)
+ * @param loc_next the location of a \c next pointer within your node struct (required)
+ */
+void cx_linked_list_reverse(
+        void **begin,
+        void **end,
+        ptrdiff_t loc_prev,
+        ptrdiff_t loc_next
+) __attribute__((__nonnull__(1)));
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+
+#endif // UCX_LINKED_LIST_H