src/cx/tree.h

/*
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
 *
 * Copyright 2024 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 tree.h
 * \brief Interface for tree implementations.
 * \author Mike Becker
 * \author Olaf Wintermann
 * \copyright 2-Clause BSD License
 */

#ifndef UCX_TREE_H
#define UCX_TREE_H

#include "common.h"

#ifdef __cplusplus
extern "C" {
#endif


/**
 * Links a node to a (new) parent.
 *
 * If the node has already a parent, it is unlinked, first.
 *
 * @param parent the parent node
 * @param node the node that shall be linked
 * @param loc_parent offset in the node struct for the parent pointer
 * @param loc_children offset in the node struct for the children linked list
 * @param loc_prev offset in the node struct for the prev pointer
 * @param loc_next offset in the node struct for the next pointer
 * @see cx_tree_unlink()
 */
__attribute__((__nonnull__))
void cx_tree_link(
        void * restrict parent,
        void * restrict node,
        ptrdiff_t loc_parent,
        ptrdiff_t loc_children,
        ptrdiff_t loc_prev,
        ptrdiff_t loc_next
);

/**
 * Unlinks a node from its parent.
 *
 * If the node has no parent, this function does nothing.
 *
 * @param node the node that shall be unlinked from its parent
 * @param loc_parent offset in the node struct for the parent pointer
 * @param loc_children offset in the node struct for the children linked list
 * @param loc_prev offset in the node struct for the prev pointer
 * @param loc_next offset in the node struct for the next pointer
 * @see cx_tree_link()
 */
__attribute__((__nonnull__))
void cx_tree_unlink(
        void *node,
        ptrdiff_t loc_parent,
        ptrdiff_t loc_children,
        ptrdiff_t loc_prev,
        ptrdiff_t loc_next
);

/**
 * Function pointer for a search function.
 *
 * A function of this kind shall check if the specified \p node
 * contains the given \p data or if one of the children might contain
 * the data.
 *
 * For example if a tree stores file path information, a node that is
 * describing a parent directory of a filename that is searched, shall
 * return 1 to indicate that a child node might contain the searched item.
 * On the other hand, if the node denotes a path that is not a prefix of
 * the searched filename, the function would return -1 to indicate that
 * the search does not need to be continued in that branch.
 *
 * @param node the node that is currently investigated
 * @param data the data that is searched for
 *
 * @return 0 if the node contains the data,
 * 1 if one of the children might contain the data,
 * -1 if neither the node, nor the children contains the data
 */
typedef int (*cx_tree_search_func)(void const *node, void const* data);

#ifdef __cplusplus
} // extern "C"
#endif

#endif //UCX_TREE_H