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/*************************************************************************
* Copyright (c) 2011 AT&T Intellectual Property
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* https://www.eclipse.org/legal/epl-v10.html
*
* Contributors: Details at https://graphviz.org
*************************************************************************/
#include <stdlib.h>
#include <inttypes.h>
#include <label/index.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include <stdio.h>
#include <assert.h>
#include <label/node.h>
#include <util/alloc.h>
/* Make a new node and initialize to have all branch cells empty.
*/
Node_t *RTreeNewNode(void) {
Node_t *n = gv_alloc(sizeof(Node_t));
InitNode(n);
return n;
}
/* Initialize a Node structure.
*/
void InitNode(Node_t * n)
{
n->count = 0;
n->level = -1;
for (size_t i = 0; i < NODECARD; i++)
InitBranch(&(n->branch[i]));
}
/* Initialize one branch cell in a node.
*/
void InitBranch(Branch_t * b)
{
InitRect(&(b->rect));
b->child = NULL;
}
#ifdef RTDEBUG
/* Print out the data in a node.
*/
void PrintNode(Node_t * n)
{
assert(n);
fprintf(stderr, "node");
if (n->level == 0)
fprintf(stderr, " LEAF");
else if (n->level > 0)
fprintf(stderr, " NONLEAF");
else
fprintf(stderr, " TYPE=?");
fprintf(stderr, " level=%d count=%d child address=%p\n",
n->level, n->count, n);
for (size_t i = 0; i < NODECARD; i++) {
if (n->branch[i].child != NULL)
PrintBranch(i, &n->branch[i]);
}
}
void PrintBranch(int i, Branch_t * b)
{
fprintf(stderr, " child[%d] X%X\n", i, (unsigned int) b->child);
PrintRect(b->rect);
}
#endif
/* Find the smallest rectangle that includes all rectangles in
** branches of a node.
*/
Rect_t NodeCover(Node_t * n)
{
Rect_t r;
assert(n);
InitRect(&r);
bool flag = true;
for (size_t i = 0; i < NODECARD; i++)
if (n->branch[i].child) {
if (flag) {
r = n->branch[i].rect;
flag = false;
} else
r = CombineRect(r, n->branch[i].rect);
}
return r;
}
/* Pick a branch. Pick the one that will need the smallest increase
** in area to accommodate the new rectangle. This will result in the
** least total area for the covering rectangles in the current node.
** In case of a tie, pick the one which was smaller before, to get
** the best resolution when searching.
*/
int PickBranch(Rect_t r, Node_t *n) {
uint64_t bestIncr = 0;
uint64_t bestArea = 0;
int best=0;
bool bestSet = false;
assert(n);
for (int i = 0; i < NODECARD; i++) {
if (n->branch[i].child) {
const Rect_t rr = n->branch[i].rect;
uint64_t area = RectArea(rr);
Rect_t rect = CombineRect(r, rr);
uint64_t increase = RectArea(rect) - area;
if (!bestSet || increase < bestIncr) {
best = i;
bestArea = area;
bestIncr = increase;
bestSet = true;
} else if (increase == bestIncr && area < bestArea) {
best = i;
bestArea = area;
bestIncr = increase;
}
# ifdef RTDEBUG
fprintf(stderr,
"i=%d area before=%" PRIu64 " area after=%" PRIu64 " increase=%" PRIu64
"\n", i, area, area + increase, increase);
# endif
}
}
# ifdef RTDEBUG
fprintf(stderr, "\tpicked %d\n", best);
# endif
return best;
}
/* Add a branch to a node. Split the node if necessary.
** Returns 0 if node not split. Old node updated.
** Returns 1 if node split, sets *new to address of new node.
** Old node updated, becomes one of two.
*/
int AddBranch(RTree_t * rtp, Branch_t * b, Node_t * n, Node_t ** new)
{
assert(b);
assert(n);
if (n->count < NODECARD) { /* split won't be necessary */
size_t i;
for (i = 0; i < NODECARD; i++) { /* find empty branch */
if (n->branch[i].child == NULL) {
n->branch[i] = *b;
n->count++;
break;
}
}
assert(i < NODECARD);
return 0;
} else {
assert(new);
SplitNode(rtp, n, b, new);
return 1;
}
}
/* Disconnect a dependent node.
*/
void DisconBranch(Node_t * n, int i)
{
assert(n && i >= 0 && i < NODECARD);
assert(n->branch[i].child);
InitBranch(&(n->branch[i]));
n->count--;
}
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