Thu, 15 Feb 2024 21:54:43 +0100
add cx_tree_search() - relates to #165
universe@816 | 1 | /* |
universe@816 | 2 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER. |
universe@816 | 3 | * |
universe@816 | 4 | * Copyright 2024 Mike Becker, Olaf Wintermann All rights reserved. |
universe@816 | 5 | * |
universe@816 | 6 | * Redistribution and use in source and binary forms, with or without |
universe@816 | 7 | * modification, are permitted provided that the following conditions are met: |
universe@816 | 8 | * |
universe@816 | 9 | * 1. Redistributions of source code must retain the above copyright |
universe@816 | 10 | * notice, this list of conditions and the following disclaimer. |
universe@816 | 11 | * |
universe@816 | 12 | * 2. Redistributions in binary form must reproduce the above copyright |
universe@816 | 13 | * notice, this list of conditions and the following disclaimer in the |
universe@816 | 14 | * documentation and/or other materials provided with the distribution. |
universe@816 | 15 | * |
universe@816 | 16 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
universe@816 | 17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
universe@816 | 18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
universe@816 | 19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE |
universe@816 | 20 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
universe@816 | 21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
universe@816 | 22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
universe@816 | 23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
universe@816 | 24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
universe@816 | 25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
universe@816 | 26 | * POSSIBILITY OF SUCH DAMAGE. |
universe@816 | 27 | */ |
universe@816 | 28 | |
universe@816 | 29 | #include "cx/tree.h" |
universe@816 | 30 | |
universe@826 | 31 | #include "cx/array_list.h" |
universe@826 | 32 | |
universe@816 | 33 | #include <assert.h> |
universe@816 | 34 | |
universe@816 | 35 | #define CX_TREE_PTR(cur, off) (*(void**)(((char*)(cur))+(off))) |
universe@816 | 36 | #define CX_TREE_PTR(cur, off) (*(void**)(((char*)(cur))+(off))) |
universe@816 | 37 | #define tree_parent(node) CX_TREE_PTR(node, loc_parent) |
universe@816 | 38 | #define tree_children(node) CX_TREE_PTR(node, loc_children) |
universe@816 | 39 | #define tree_prev(node) CX_TREE_PTR(node, loc_prev) |
universe@816 | 40 | #define tree_next(node) CX_TREE_PTR(node, loc_next) |
universe@816 | 41 | |
universe@816 | 42 | void cx_tree_link( |
universe@816 | 43 | void *restrict parent, |
universe@816 | 44 | void *restrict node, |
universe@816 | 45 | ptrdiff_t loc_parent, |
universe@816 | 46 | ptrdiff_t loc_children, |
universe@816 | 47 | ptrdiff_t loc_prev, |
universe@816 | 48 | ptrdiff_t loc_next |
universe@816 | 49 | ) { |
universe@816 | 50 | void *current_parent = tree_parent(node); |
universe@816 | 51 | if (current_parent == parent) return; |
universe@816 | 52 | if (current_parent != NULL) { |
universe@816 | 53 | cx_tree_unlink(node, loc_parent, loc_children, |
universe@816 | 54 | loc_prev, loc_next); |
universe@816 | 55 | } |
universe@816 | 56 | |
universe@816 | 57 | if (tree_children(parent) == NULL) { |
universe@816 | 58 | tree_children(parent) = node; |
universe@816 | 59 | } else { |
universe@816 | 60 | void *children = tree_children(parent); |
universe@816 | 61 | tree_prev(children) = node; |
universe@816 | 62 | tree_next(node) = children; |
universe@816 | 63 | tree_children(parent) = node; |
universe@816 | 64 | } |
universe@816 | 65 | tree_parent(node) = parent; |
universe@816 | 66 | } |
universe@816 | 67 | |
universe@816 | 68 | void cx_tree_unlink( |
universe@816 | 69 | void *node, |
universe@816 | 70 | ptrdiff_t loc_parent, |
universe@816 | 71 | ptrdiff_t loc_children, |
universe@816 | 72 | ptrdiff_t loc_prev, |
universe@816 | 73 | ptrdiff_t loc_next |
universe@816 | 74 | ) { |
universe@816 | 75 | if (tree_parent(node) == NULL) return; |
universe@816 | 76 | |
universe@816 | 77 | void *left = tree_prev(node); |
universe@816 | 78 | void *right = tree_next(node); |
universe@816 | 79 | assert(left == NULL || tree_children(tree_parent(node)) != node); |
universe@816 | 80 | if (left == NULL) { |
universe@816 | 81 | tree_children(tree_parent(node)) = right; |
universe@816 | 82 | } else { |
universe@816 | 83 | tree_next(left) = right; |
universe@816 | 84 | } |
universe@816 | 85 | if (right != NULL) tree_prev(right) = left; |
universe@816 | 86 | tree_parent(node) = NULL; |
universe@816 | 87 | tree_prev(node) = NULL; |
universe@816 | 88 | tree_next(node) = NULL; |
universe@816 | 89 | } |
universe@826 | 90 | |
universe@826 | 91 | int cx_tree_search( |
universe@826 | 92 | void const *root, |
universe@826 | 93 | void const *data, |
universe@826 | 94 | cx_tree_search_func sfunc, |
universe@826 | 95 | void **result, |
universe@826 | 96 | ptrdiff_t loc_children, |
universe@826 | 97 | ptrdiff_t loc_next |
universe@826 | 98 | ) { |
universe@826 | 99 | int ret; |
universe@826 | 100 | *result = NULL; |
universe@826 | 101 | |
universe@826 | 102 | // shortcut: compare root before doing anything else |
universe@826 | 103 | ret = sfunc(root, data); |
universe@826 | 104 | if (ret < 0) { |
universe@826 | 105 | return ret; |
universe@826 | 106 | } else if (ret == 0 || tree_children(root) == NULL) { |
universe@826 | 107 | *result = (void*)root; |
universe@826 | 108 | return ret; |
universe@826 | 109 | } |
universe@826 | 110 | |
universe@826 | 111 | // create a working stack |
universe@826 | 112 | size_t work_cap = 32; |
universe@826 | 113 | size_t work_size = 0; |
universe@826 | 114 | void const **work = malloc(sizeof(void*) * work_cap); |
universe@826 | 115 | #define work_add(node) cx_array_add(&work, &work_size, &work_cap, \ |
universe@826 | 116 | sizeof(void*), &(node), cx_array_default_reallocator) |
universe@826 | 117 | |
universe@826 | 118 | // add the children of root to the working stack |
universe@826 | 119 | { |
universe@826 | 120 | void *c = tree_children(root); |
universe@826 | 121 | while (c != NULL) { |
universe@826 | 122 | work_add(c); |
universe@826 | 123 | c = tree_next(c); |
universe@826 | 124 | } |
universe@826 | 125 | } |
universe@826 | 126 | |
universe@826 | 127 | // remember a candidate for adding the data |
universe@826 | 128 | // also remember the exact return code from sfunc |
universe@826 | 129 | void *candidate = NULL; |
universe@826 | 130 | int ret_candidate = -1; |
universe@826 | 131 | |
universe@826 | 132 | // process the working stack |
universe@826 | 133 | while (work_size > 0) { |
universe@826 | 134 | // pop element |
universe@826 | 135 | void const *node = work[--work_size]; |
universe@826 | 136 | |
universe@826 | 137 | // apply the search function |
universe@826 | 138 | ret = sfunc(node, data); |
universe@826 | 139 | |
universe@826 | 140 | if (ret == 0) { |
universe@826 | 141 | // if found, exit the search |
universe@826 | 142 | *result = (void*) node; |
universe@826 | 143 | work_size = 0; |
universe@826 | 144 | break; |
universe@826 | 145 | } else if (ret > 0) { |
universe@826 | 146 | // if children might contain the data, add them to the stack |
universe@826 | 147 | void *c = tree_children(node); |
universe@826 | 148 | while (c != NULL) { |
universe@826 | 149 | work_add(c); |
universe@826 | 150 | c = tree_next(c); |
universe@826 | 151 | } |
universe@826 | 152 | |
universe@826 | 153 | // remember this node in case no child is suitable |
universe@826 | 154 | if (ret_candidate < 0 || ret < ret_candidate) { |
universe@826 | 155 | candidate = (void *) node; |
universe@826 | 156 | ret_candidate = ret; |
universe@826 | 157 | } |
universe@826 | 158 | } |
universe@826 | 159 | } |
universe@826 | 160 | |
universe@826 | 161 | // not found, but was there a candidate? |
universe@826 | 162 | if (ret != 0 && candidate != NULL) { |
universe@826 | 163 | ret = ret_candidate; |
universe@826 | 164 | *result = candidate; |
universe@826 | 165 | } |
universe@826 | 166 | |
universe@826 | 167 | // free the working queue and return |
universe@826 | 168 | #undef workq_add |
universe@826 | 169 | free(work); |
universe@826 | 170 | return ret; |
universe@826 | 171 | } |