ucx: src/tree.c@c4dae6fe6d5b (annotated)

src/tree.c@c4dae6fe6d5b (annotated)

src/tree.c

Sun, 18 Feb 2024 12:24:04 +0100

author: Mike Becker <universe@uap-core.de>
date: Sun, 18 Feb 2024 12:24:04 +0100
changeset 830: c4dae6fe6d5b
parent 826: 21840975d541
child 833: 5c926801f052
permissions: -rw-r--r--

commit complicated stuff before simplifying it

relates to #371

 /*
  * 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.
  */
 #include "cx/tree.h"
 #include "cx/array_list.h"
 #include <assert.h>
 #define CX_TREE_PTR(cur, off) (*(void**)(((char*)(cur))+(off)))
 #define CX_TREE_PTR(cur, off) (*(void**)(((char*)(cur))+(off)))
 #define tree_parent(node) CX_TREE_PTR(node, loc_parent)
 #define tree_children(node) CX_TREE_PTR(node, loc_children)
 #define tree_prev(node) CX_TREE_PTR(node, loc_prev)
 #define tree_next(node) CX_TREE_PTR(node, loc_next)
 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
 ) {
     void *current_parent = tree_parent(node);
     if (current_parent == parent) return;
     if (current_parent != NULL) {
         cx_tree_unlink(node, loc_parent, loc_children,
                        loc_prev, loc_next);
     }
     if (tree_children(parent) == NULL) {
         tree_children(parent) = node;
     } else {
         void *children = tree_children(parent);
         tree_prev(children) = node;
         tree_next(node) = children;
         tree_children(parent) = node;
     }
     tree_parent(node) = parent;
 }
 void cx_tree_unlink(
         void *node,
         ptrdiff_t loc_parent,
         ptrdiff_t loc_children,
         ptrdiff_t loc_prev,
         ptrdiff_t loc_next
 ) {
     if (tree_parent(node) == NULL) return;
     void *left = tree_prev(node);
     void *right = tree_next(node);
     assert(left == NULL || tree_children(tree_parent(node)) != node);
     if (left == NULL) {
         tree_children(tree_parent(node)) = right;
     } else {
         tree_next(left) = right;
     }
     if (right != NULL) tree_prev(right) = left;
     tree_parent(node) = NULL;
     tree_prev(node) = NULL;
     tree_next(node) = NULL;
 }
 int cx_tree_search(
         void const *root,
         void const *data,
         cx_tree_search_func sfunc,
         void **result,
         ptrdiff_t loc_children,
         ptrdiff_t loc_next
 ) {
     int ret;
     *result = NULL;
     // shortcut: compare root before doing anything else
     ret = sfunc(root, data);
     if (ret < 0) {
         return ret;
     } else if (ret == 0 || tree_children(root) == NULL) {
         *result = (void*)root;
         return ret;
     }
     // create a working stack
     size_t work_cap = 32;
     size_t work_size = 0;
     void const **work = malloc(sizeof(void*) * work_cap);
     #define work_add(node) cx_array_add(&work, &work_size, &work_cap, \
         sizeof(void*), &(node), cx_array_default_reallocator)
     // add the children of root to the working stack
     {
         void *c = tree_children(root);
         while (c != NULL) {
             work_add(c);
             c = tree_next(c);
         }
     }
     // remember a candidate for adding the data
     // also remember the exact return code from sfunc
     void *candidate = NULL;
     int ret_candidate = -1;
     // process the working stack
     while (work_size > 0) {
         // pop element
         void const *node = work[--work_size];
         // apply the search function
         ret = sfunc(node, data);
         if (ret == 0) {
             // if found, exit the search
             *result = (void*) node;
             work_size = 0;
             break;
         } else if (ret > 0) {
             // if children might contain the data, add them to the stack
             void *c = tree_children(node);
             while (c != NULL) {
                 work_add(c);
                 c = tree_next(c);
             }
             // remember this node in case no child is suitable
             if (ret_candidate < 0 || ret < ret_candidate) {
                 candidate = (void *) node;
                 ret_candidate = ret;
             }
         }
     }
     // not found, but was there a candidate?
     if (ret != 0 && candidate != NULL) {
         ret = ret_candidate;
         *result = candidate;
     }
     // free the working queue and return
     #undef workq_add
     free(work);
     return ret;
 }
 static bool cx_tree_iter_valid(void const *it) {
     struct cx_tree_iterator_s const *iter = it;
     return iter->node != NULL;
 }
 static void *cx_tree_iter_current(void const *it) {
     struct cx_tree_iterator_s const *iter = it;
     return iter->node;
 }
 static void cx_tree_iter_stack_add(
         struct cx_tree_iterator_s *iter,
         void *node
 ) {
     cx_array_add(&iter->stack, &iter->depth, &iter->stack_capacity,
         sizeof(void*), &node, cx_array_default_reallocator);
 }
 static void cx_tree_iter_next(void *it) {
     struct cx_tree_iterator_s *iter = it;
     // TODO: support mutating iterator
     // TODO: implement
 }
 CxTreeIterator cx_tree_iterator(
         void *root,
         int passes,
         ptrdiff_t loc_children,
         ptrdiff_t loc_next
 ) {
     CxTreeIterator iter;
     iter.loc_children = loc_children;
     iter.loc_next = loc_next;
     iter.requested_passes = passes;
     // invalidate iterator immediately when passes is invalid
     if ((passes & (CX_TREE_ITERATOR_ENTER |
                    CX_TREE_ITERATOR_NEXT_CHILD |
                    CX_TREE_ITERATOR_EXIT)) == 0) {
         iter.stack = NULL;
         iter.node = NULL;
         return iter;
     }
     // allocate stack
     iter.stack_capacity = 16;
     iter.stack = malloc(sizeof(void *) * 16);
     iter.depth = 0;
     // determine start
     if ((passes & CX_TREE_ITERATOR_ENTER) == 0) {
         // we have to skip the first "entering" passes
         void *s = NULL;
         void *n = root;
         iter.counter = 0;
         do {
             iter.counter++;
             iter.source = s;
             iter.node = n;
             cx_tree_iter_stack_add(&iter, n);
             s = n;
             n = tree_children(n);
         } while (n != NULL);
         // found a leaf node s (might be root itself if it has no children)
         // check if there is a sibling
         n = tree_next(s);
         if (n == NULL) {
             // no sibling found, exit back to parent node
             // TODO: implement
         } else {
             // there is a sibling
             if ((passes & CX_TREE_ITERATOR_EXIT) == 0) {
                 // no exit requested, conclude that only next_child is requested
                 iter.source = s;
                 iter.node = n;
                 iter.counter++;
                 iter.current_pass = CX_TREE_ITERATOR_NEXT_CHILD;
             } else {
                 // exit requested, so we have found our first pass
                 // iter.node and iter.source are still correct
                 iter.current_pass = CX_TREE_ITERATOR_EXIT;
             }
         }
     } else {
         // enter passes are requested, we can start by entering the root node
         iter.source = NULL;
         iter.node = root;
         iter.current_pass = CX_TREE_ITERATOR_ENTER;
         iter.counter = 1;
         iter.depth = 1;
         iter.stack[0] = root;
     }
     // assign base iterator functions
     iter.base.mutating = false;
     iter.base.remove = false;
     iter.base.current_impl = NULL;
     iter.base.valid = cx_tree_iter_valid;
     iter.base.next = cx_tree_iter_next;
     iter.base.current = cx_tree_iter_current;
     return iter;
 }

Mercurial > hg > ucx / annotate

src/tree.c@c4dae6fe6d5b (annotated)

src/tree.c