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/*
* The JTS Topology Suite is a collection of Java classes that
* implement the fundamental operations required to validate a given
* geo-spatial data set to a known topological specification.
*
* Copyright (C) 2001 Vivid Solutions
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* For more information, contact:
*
* Vivid Solutions
* Suite #1A
* 2328 Government Street
* Victoria BC V8T 5G5
* Canada
*
* (250)385-6040
* www.vividsolutions.com
*/
package com.vividsolutions.jts.geom;
import java.util.*;
import com.vividsolutions.jts.math.MathUtil;
/**
* Useful utility functions for handling Coordinate arrays
*
* @version 1.7
*/
public class CoordinateArrays {
private final static Coordinate[] coordArrayType = new Coordinate[0];
/**
* Tests whether an array of {@link Coordinate}s forms a ring,
* by checking length and closure.
* Self-intersection is not checked.
*
* @param pts an array of Coordinates
* @return true if the coordinate form a ring.
*/
public static boolean isRing(Coordinate[] pts)
{
if (pts.length < 4) return false;
if (! pts[0].equals2D(pts[pts.length -1])) return false;
return true;
}
/**
* Finds a point in a list of points which is not contained in another list of points
* @param testPts the {@link Coordinate}s to test
* @param pts an array of {@link Coordinate}s to test the input points against
* @return a {@link Coordinate} from testPts which is not in pts, '
* or null
*/
public static Coordinate ptNotInList(Coordinate[] testPts, Coordinate[] pts)
{
for (int i = 0; i < testPts.length; i++) {
Coordinate testPt = testPts[i];
if (CoordinateArrays.indexOf(testPt, pts) < 0)
return testPt;
}
return null;
}
/**
* Compares two {@link Coordinate} arrays
* in the forward direction of their coordinates,
* using lexicographic ordering.
*
* @param pts1
* @param pts2
* @return an integer indicating the order
*/
public static int compare(Coordinate[] pts1, Coordinate[] pts2) {
int i = 0;
while (i < pts1.length && i < pts2.length) {
int compare = pts1[i].compareTo(pts2[i]);
if (compare != 0)
return compare;
i++;
}
// handle situation when arrays are of different length
if (i < pts2.length) return -1;
if (i < pts1.length) return 1;
return 0;
}
/**
* A {@link Comparator} for {@link Coordinate} arrays
* in the forward direction of their coordinates,
* using lexicographic ordering.
*/
public static class ForwardComparator
implements Comparator
{
public int compare(Object o1, Object o2) {
Coordinate[] pts1 = (Coordinate[]) o1;
Coordinate[] pts2 = (Coordinate[]) o2;
return CoordinateArrays.compare(pts1, pts2);
}
}
/**
* Determines which orientation of the {@link Coordinate} array
* is (overall) increasing.
* In other words, determines which end of the array is "smaller"
* (using the standard ordering on {@link Coordinate}).
* Returns an integer indicating the increasing direction.
* If the sequence is a palindrome, it is defined to be
* oriented in a positive direction.
*
* @param pts the array of Coordinates to test
* @return 1 if the array is smaller at the start
* or is a palindrome,
* -1 if smaller at the end
*/
public static int increasingDirection(Coordinate[] pts) {
for (int i = 0; i < pts.length / 2; i++) {
int j = pts.length - 1 - i;
// skip equal points on both ends
int comp = pts[i].compareTo(pts[j]);
if (comp != 0)
return comp;
}
// array must be a palindrome - defined to be in positive direction
return 1;
}
/**
* Determines whether two {@link Coordinate} arrays of equal length
* are equal in opposite directions.
*
* @param pts1
* @param pts2
* @return true if the two arrays are equal in opposite directions.
*/
private static boolean isEqualReversed(Coordinate[] pts1, Coordinate[] pts2)
{
for (int i = 0; i < pts1.length; i++) {
Coordinate p1 = pts1[i];
Coordinate p2 = pts2[pts1.length - i - 1];
if (p1.compareTo(p2) != 0)
return false;
}
return true;
}
/**
* A {@link Comparator} for {@link Coordinate} arrays
* modulo their directionality.
* E.g. if two coordinate arrays are identical but reversed
* they will compare as equal under this ordering.
* If the arrays are not equal, the ordering returned
* is the ordering in the forward direction.
*
*/
public static class BidirectionalComparator
implements Comparator
{
public int compare(Object o1, Object o2) {
Coordinate[] pts1 = (Coordinate[]) o1;
Coordinate[] pts2 = (Coordinate[]) o2;
if (pts1.length < pts2.length) return -1;
if (pts1.length > pts2.length) return 1;
if (pts1.length == 0) return 0;
int forwardComp = CoordinateArrays.compare(pts1, pts2);
boolean isEqualRev = isEqualReversed(pts1, pts2);
if (isEqualRev)
return 0;
return forwardComp;
}
public int OLDcompare(Object o1, Object o2) {
Coordinate[] pts1 = (Coordinate[]) o1;
Coordinate[] pts2 = (Coordinate[]) o2;
if (pts1.length < pts2.length) return -1;
if (pts1.length > pts2.length) return 1;
if (pts1.length == 0) return 0;
int dir1 = increasingDirection(pts1);
int dir2 = increasingDirection(pts2);
int i1 = dir1 > 0 ? 0 : pts1.length - 1;
int i2 = dir2 > 0 ? 0 : pts1.length - 1;
for (int i = 0; i < pts1.length; i++) {
int comparePt = pts1[i1].compareTo(pts2[i2]);
if (comparePt != 0)
return comparePt;
i1 += dir1;
i2 += dir2;
}
return 0;
}
}
/**
* Creates a deep copy of the argument {@link Coordinate} array.
*
* @param coordinates an array of Coordinates
* @return a deep copy of the input
*/
public static Coordinate[] copyDeep(Coordinate[] coordinates) {
Coordinate[] copy = new Coordinate[coordinates.length];
for (int i = 0; i < coordinates.length; i++) {
copy[i] = new Coordinate(coordinates[i]);
}
return copy;
}
/**
* Creates a deep copy of a given section of a source {@link Coordinate} array
* into a destination Coordinate array.
* The destination array must be an appropriate size to receive
* the copied coordinates.
*
* @param src an array of Coordinates
* @param srcStart the index to start copying from
* @param dest the
* @param destStart the destination index to start copying to
* @param length the number of items to copy
*/
public static void copyDeep(Coordinate[] src, int srcStart, Coordinate[] dest, int destStart, int length) {
for (int i = 0; i < length; i++) {
dest[destStart + i] = new Coordinate(src[srcStart + i]);
}
}
/**
* Converts the given Collection of Coordinates into a Coordinate array.
*/
public static Coordinate[] toCoordinateArray(Collection coordList)
{
return (Coordinate[]) coordList.toArray(coordArrayType);
}
/**
* Returns whether #equals returns true for any two consecutive Coordinates
* in the given array.
*/
public static boolean hasRepeatedPoints(Coordinate[] coord)
{
for (int i = 1; i < coord.length; i++) {
if (coord[i - 1].equals(coord[i]) ) {
return true;
}
}
return false;
}
/**
* Returns either the given coordinate array if its length is greater than the
* given amount, or an empty coordinate array.
*/
public static Coordinate[] atLeastNCoordinatesOrNothing(int n, Coordinate[] c) {
return c.length >= n ? c : new Coordinate[] { };
}
/**
* If the coordinate array argument has repeated points,
* constructs a new array containing no repeated points.
* Otherwise, returns the argument.
* @see #hasRepeatedPoints(Coordinate[])
*/
public static Coordinate[] removeRepeatedPoints(Coordinate[] coord)
{
if (! hasRepeatedPoints(coord)) return coord;
CoordinateList coordList = new CoordinateList(coord, false);
return coordList.toCoordinateArray();
}
/**
* Collapses a coordinate array to remove all null elements.
*
* @param coord the coordinate array to collapse
* @return an array containing only non-null elements
*/
public static Coordinate[] removeNull(Coordinate[] coord)
{
int nonNull = 0;
for (int i = 0; i < coord.length; i++) {
if (coord[i] != null) nonNull++;
}
Coordinate[] newCoord = new Coordinate[nonNull];
// empty case
if (nonNull == 0) return newCoord;
int j = 0;
for (int i = 0; i < coord.length; i++) {
if (coord[i] != null) newCoord[j++] = coord[i];
}
return newCoord;
}
/**
* Reverses the coordinates in an array in-place.
*/
public static void reverse(Coordinate[] coord)
{
int last = coord.length - 1;
int mid = last / 2;
for (int i = 0; i <= mid; i++) {
Coordinate tmp = coord[i];
coord[i] = coord[last - i];
coord[last - i] = tmp;
}
}
/**
* Returns true if the two arrays are identical, both null, or pointwise
* equal (as compared using Coordinate#equals)
* @see Coordinate#equals(Object)
*/
public static boolean equals(
Coordinate[] coord1,
Coordinate[] coord2)
{
if (coord1 == coord2) return true;
if (coord1 == null || coord2 == null) return false;
if (coord1.length != coord2.length) return false;
for (int i = 0; i < coord1.length; i++) {
if (! coord1[i].equals(coord2[i])) return false;
}
return true;
}
/**
* Returns true if the two arrays are identical, both null, or pointwise
* equal, using a user-defined {@link Comparator} for {@link Coordinate} s
*
* @param coord1 an array of Coordinates
* @param coord2 an array of Coordinates
* @param coordinateComparator a Comparator for Coordinates
*/
public static boolean equals(
Coordinate[] coord1,
Coordinate[] coord2,
Comparator coordinateComparator)
{
if (coord1 == coord2) return true;
if (coord1 == null || coord2 == null) return false;
if (coord1.length != coord2.length) return false;
for (int i = 0; i < coord1.length; i++) {
if (coordinateComparator.compare(coord1[i], coord2[i]) != 0)
return false;
}
return true;
}
/**
* Returns the minimum coordinate, using the usual lexicographic comparison.
*
*@param coordinates the array to search
*@return the minimum coordinate in the array, found using compareTo
*@see Coordinate#compareTo(Object)
*/
public static Coordinate minCoordinate(Coordinate[] coordinates)
{
Coordinate minCoord = null;
for (int i = 0; i < coordinates.length; i++) {
if (minCoord == null || minCoord.compareTo(coordinates[i]) > 0) {
minCoord = coordinates[i];
}
}
return minCoord;
}
/**
* Shifts the positions of the coordinates until firstCoordinate
* is first.
*
*@param coordinates the array to rearrange
*@param firstCoordinate the coordinate to make first
*/
public static void scroll(Coordinate[] coordinates, Coordinate firstCoordinate) {
int i = indexOf(firstCoordinate, coordinates);
if (i < 0) return;
Coordinate[] newCoordinates = new Coordinate[coordinates.length];
System.arraycopy(coordinates, i, newCoordinates, 0, coordinates.length - i);
System.arraycopy(coordinates, 0, newCoordinates, coordinates.length - i, i);
System.arraycopy(newCoordinates, 0, coordinates, 0, coordinates.length);
}
/**
* Returns the index of coordinate in coordinates.
* The first position is 0; the second, 1; etc.
*
*@param coordinate the Coordinate to search for
*@param coordinates the array to search
*@return the position of coordinate, or -1 if it is
* not found
*/
public static int indexOf(Coordinate coordinate, Coordinate[] coordinates) {
for (int i = 0; i < coordinates.length; i++) {
if (coordinate.equals(coordinates[i])) {
return i;
}
}
return -1;
}
/**
* Extracts a subsequence of the input {@link Coordinate} array
* from indices start to
* end (inclusive).
* The input indices are clamped to the array size;
* If the end index is less than the start index,
* the extracted array will be empty.
*
* @param pts the input array
* @param start the index of the start of the subsequence to extract
* @param end the index of the end of the subsequence to extract
* @return a subsequence of the input array
*/
public static Coordinate[] extract(Coordinate[] pts, int start, int end)
{
start = MathUtil.clamp(start, 0, pts.length);
end = MathUtil.clamp(end, -1, pts.length);
int npts = end - start + 1;
if (end < 0) npts = 0;
if (start >= pts.length) npts = 0;
if (end < start) npts = 0;
Coordinate[] extractPts = new Coordinate[npts];
if (npts == 0) return extractPts;
int iPts = 0;
for (int i = start; i <= end; i++) {
extractPts[iPts++] = pts[i];
}
return extractPts;
}
/**
* Computes the envelope of the coordinates.
*
* @param coordinates the coordinates to scan
* @return the envelope of the coordinates
*/
public static Envelope envelope(Coordinate[] coordinates) {
Envelope env = new Envelope();
for (int i = 0; i < coordinates.length; i++) {
env.expandToInclude(coordinates[i]);
}
return env;
}
/**
* Extracts the coordinates which intersect an {@link Envelope}.
*
* @param coordinates the coordinates to scan
* @param env the envelope to intersect with
* @return an array of the coordinates which intersect the envelope
*/
public static Coordinate[] intersection(Coordinate[] coordinates, Envelope env) {
CoordinateList coordList = new CoordinateList();
for (int i = 0; i < coordinates.length; i++) {
if (env.intersects(coordinates[i]))
coordList.add(coordinates[i], true);
}
return coordList.toCoordinateArray();
}
}