rectangle.c

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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 "config.h"
 
#include <label/index.h>
#include <math.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <common/arith.h>
#include <label/rectangle.h>
#include <cgraph/cgraph.h>
#include <util/exit.h>
 
static bool Undefined(Rect_t r) { return r.boundary[0] > r.boundary[NUMDIMS]; }
 
/*-----------------------------------------------------------------------------
| Initialize a rectangle to have all 0 coordinates.
-----------------------------------------------------------------------------*/
void InitRect(Rect_t * r)
{
    for (size_t i = 0; i < NUMSIDES; i++)
        r->boundary[i] = 0;
}
 
/*-----------------------------------------------------------------------------
| Return a rect whose first low side is higher than its opposite side -
| interpreted as an undefined rect.
-----------------------------------------------------------------------------*/
Rect_t NullRect(void)
{
    Rect_t r = {{0}};
 
    r.boundary[0] = 1;
    r.boundary[NUMDIMS] = -1;
    return r;
}
 
#ifdef RTDEBUG
/*-----------------------------------------------------------------------------
| Print rectangle lower upper bounds by dimension
-----------------------------------------------------------------------------*/
void PrintRect(Rect_t r) {
    fprintf(stderr, "rect:");
    for (size_t i = 0; i < NUMDIMS; i++)
        fprintf(stderr, "\t%.0f\t%.0f\n", r.boundary[i], r.boundary[i + NUMDIMS]);
}
#endif
 
/*-----------------------------------------------------------------------------
| Calculate the n-dimensional area of a rectangle
-----------------------------------------------------------------------------*/
 
uint64_t RectArea(const Rect_t r) {
    if (Undefined(r))
        return 0;
 
    uint64_t area = 1;
    for (size_t i = 0; i < NUMDIMS; i++) {
      const uint64_t dim = (uint64_t)(r.boundary[i + NUMDIMS] - r.boundary[i]);
      if (dim == 0) return 0;
      if (UINT64_MAX / dim < area) {
        agerrorf("label: area too large for rtree\n");
        graphviz_exit(EXIT_FAILURE);
      }
      area *= dim;
    }
    return area;
}
 
/*-----------------------------------------------------------------------------
| Combine two rectangles, make one that includes both.
-----------------------------------------------------------------------------*/
Rect_t CombineRect(const Rect_t r, const Rect_t rr) {
    Rect_t new;
 
    if (Undefined(r))
        return rr;
    if (Undefined(rr))
        return r;
 
    for (size_t i = 0; i < NUMDIMS; i++) {
        new.boundary[i] = fmin(r.boundary[i], rr.boundary[i]);
        size_t j = i + NUMDIMS;
        new.boundary[j] = fmin(r.boundary[j], rr.boundary[j]);
    }
    return new;
}
 
/*-----------------------------------------------------------------------------
| Decide whether two rectangles overlap.
-----------------------------------------------------------------------------*/
bool Overlap(const Rect_t r, const Rect_t s) {
    for (size_t i = 0; i < NUMDIMS; i++) {
        size_t j = i + NUMDIMS; /* index for high sides */
        if (r.boundary[i] > s.boundary[j] || s.boundary[i] > r.boundary[j])
            return false;
    }
    return true;
}