/* Copyright 2011-2012 Space Applications Services
* Licensed to CS Communication & Systèmes (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.orekit.utils;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;
import java.text.ParseException;
import java.util.LinkedList;
import java.util.List;
import org.orekit.data.DataLoader;
import org.orekit.errors.OrekitException;
/** Used to read an interpolation table from a data file.
* @author Thomas Neidhart
*/
public class InterpolationTableLoader implements DataLoader {
/** Abscissa grid for the bi-variate interpolation function read from the file. */
private double[] xArr;
/** Ordinate grid for the bi-variate interpolation function read from the file. */
private double[] yArr;
/** Values samples for the bi-variate interpolation function read from the file. */
private double[][] fArr;
/** Returns a copy of the abscissa grid for the interpolation function.
* @return the abscissa grid for the interpolation function,
* or <code>null</code> if the file could not be read
*/
public double[] getAbscissaGrid() {
return xArr.clone();
}
/** Returns a copy of the ordinate grid for the interpolation function.
* @return the ordinate grid for the interpolation function,
* or <code>null</code> if the file could not be read
*/
public double[] getOrdinateGrid() {
return yArr.clone();
}
/** Returns a copy of the values samples for the interpolation function.
* @return the values samples for the interpolation function,
* or <code>null</code> if the file could not be read
*/
public double[][] getValuesSamples() {
return fArr.clone();
}
/** {@inheritDoc} */
public boolean stillAcceptsData() {
return xArr == null;
}
/** Loads an bi-variate interpolation table from the given {@link InputStream}.
* The format of the table is as follows (number of rows/columns can be extended):
* <pre>
* Table: tableName
*
* | 0.0 | 60.0 | 66.0
* -------------------------
* 0 | 0.0 | 0.003 | 0.006
* 500 | 0.0 | 0.003 | 0.006
* </pre>
* @param input the input stream to read data from
* @param name the name of the input file
* @exception IOException if data can't be read
* @exception ParseException if data can't be parsed
* @exception OrekitException if some data is missing or unexpected
* data is encountered
*/
public void loadData(final InputStream input, final String name)
throws IOException, ParseException, OrekitException {
final List<Double> xValues = new LinkedList<Double>();
final List<Double> yValues = new LinkedList<Double>();
final LinkedList<List<Double>> cellValues = new LinkedList<List<Double>>();
final StreamTokenizer tokenizer =
new StreamTokenizer(new BufferedReader(new InputStreamReader(input, "UTF-8")));
// ignore comments starting with a #
tokenizer.commentChar('#');
tokenizer.eolIsSignificant(true);
int tokenCount = 0;
boolean headerRow = false;
boolean done = false;
do {
switch (tokenizer.nextToken()) {
case StreamTokenizer.TT_EOF:
done = true;
break;
case StreamTokenizer.TT_EOL:
// end of header row
if (yValues.size() > 0) {
headerRow = false;
}
tokenCount = 0;
break;
case StreamTokenizer.TT_NUMBER:
if (headerRow) {
yValues.add(tokenizer.nval);
} else {
if (tokenCount == 0) {
xValues.add(tokenizer.nval);
cellValues.add(new LinkedList<Double>());
} else {
cellValues.getLast().add(tokenizer.nval);
}
}
tokenCount++;
break;
case StreamTokenizer.TT_WORD:
// we are in the header row now
if (tokenizer.sval.startsWith("Table")) {
headerRow = true;
}
break;
default:
break;
}
} while (!done);
xArr = toPrimitiveArray(xValues);
yArr = toPrimitiveArray(yValues);
fArr = new double[cellValues.size()][];
int idx = 0;
for (List<Double> row : cellValues) {
fArr[idx++] = toPrimitiveArray(row);
}
}
/** Converts a list of {@link Double} objects into an array of double primitives.
* @param list the list of {@link Double} objects
* @return the double array containing the list elements
*/
private double[] toPrimitiveArray(final List<Double> list) {
final double[] result = new double[list.size()];
int idx = 0;
for (Double element : list) {
result[idx++] = element;
}
return result;
}
}