src/tree.c

/*
 * 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/tree.h"
#include "cx/linked_list.h"

#define CX_TR_PTR(cur, off) ((void**)(((char*)cur)+off))

void* cx_tree_last(void *node, ptrdiff_t loc_next) {
    void *last;
    do {
        last = node;
    } while ((node = *CX_TR_PTR(node, loc_next)) != NULL);
    return last;
}

int cx_tree_add_node(void *node, ptrdiff_t loc_parent, ptrdiff_t loc_prev, ptrdiff_t loc_next, void *new_node) {
    void *last = cx_tree_last(node, loc_next);
    if(!last)
        return 1;
    
    // next pointer must be present
    *CX_TR_PTR(last, loc_next) = new_node;
    
    // optional fields
    if(loc_parent >= 0) {
        *CX_TR_PTR(new_node, loc_parent) = *CX_TR_PTR(node, loc_parent);
    }
    if(loc_prev >= 0) {
        *CX_TR_PTR(new_node, loc_prev) = last;
    }
    
    return 0;
}

int cx_tree_add_child_node(
        void *parent,
        ptrdiff_t loc_parent,
        ptrdiff_t loc_prev,
        ptrdiff_t loc_next,
        void **children_begin,
        void **children_end,
        void *new_node)
{
    if(cx_linked_list_add(children_begin, children_end, loc_prev, loc_next, new_node)) {
        return 1;
    }
    // optional field
    if(loc_parent >= 0) {
        *CX_TR_PTR(new_node, loc_parent) = parent;
    }
    return 0;
}