TAIUTCDatFilesLoader.java
/* Copyright 2002-2019 CS Systèmes d'Information
* Licensed to CS Systèmes d'Information (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.time;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import org.hipparchus.util.FastMath;
import org.orekit.data.DataLoader;
import org.orekit.data.DataProvidersManager;
import org.orekit.errors.OrekitException;
import org.orekit.errors.OrekitMessages;
/** Loader for UTC-TAI extracted from tai-utc.dat file from USNO.
* <p>
* This class is immutable and hence thread-safe
* </p>
* @author Luc Maisonobe
* @since 7.1
*/
public class TAIUTCDatFilesLoader implements UTCTAIOffsetsLoader {
/** Default supported files name pattern. */
public static final String DEFAULT_SUPPORTED_NAMES = "^tai-utc\\.dat$";
/** Regular expression for supported files names. */
private final String supportedNames;
/** Build a loader for tai-utc.dat file from USNO.
* @param supportedNames regular expression for supported files names
*/
public TAIUTCDatFilesLoader(final String supportedNames) {
this.supportedNames = supportedNames;
}
/** {@inheritDoc} */
@Override
public List<OffsetModel> loadOffsets() {
final Parser parser = new Parser();
DataProvidersManager.getInstance().feed(supportedNames, parser);
return parser.getOffsets();
}
/** Internal class performing the parsing. */
private static class Parser implements DataLoader {
/** Regular expression for optional blanks. */
private static final String BLANKS = "\\p{Blank}*";
/** Regular expression for storage start. */
private static final String STORAGE_START = "(";
/** Regular expression for storage end. */
private static final String STORAGE_END = ")";
/** Regular expression for alternative. */
private static final String ALTERNATIVE = "|";
/** Regular expression matching blanks at start of line. */
private static final String LINE_START_REGEXP = "^" + BLANKS;
/** Regular expression matching blanks at end of line. */
private static final String LINE_END_REGEXP = BLANKS + "$";
/** Regular expression matching integers. */
private static final String INTEGER_REGEXP = "[-+]?\\p{Digit}+";
/** Regular expression matching real numbers. */
private static final String REAL_REGEXP = "[-+]?(?:(?:\\p{Digit}+(?:\\.\\p{Digit}*)?)|(?:\\.\\p{Digit}+))(?:[eE][-+]?\\p{Digit}+)?";
/** Regular expression matching an integer field to store. */
private static final String STORED_INTEGER_FIELD = BLANKS + STORAGE_START + INTEGER_REGEXP + STORAGE_END;
/** Regular expression matching a real field to store. */
private static final String STORED_REAL_FIELD = BLANKS + STORAGE_START + REAL_REGEXP + STORAGE_END;
/** Data lines pattern. */
private Pattern dataPattern;
/** UTC-TAI offsets. */
private List<OffsetModel> offsets;
/** Simple constructor.
*/
Parser() {
// data lines read:
// 1965 SEP 1 =JD 2439004.5 TAI-UTC= 3.8401300 S + (MJD - 38761.) X 0.001296 S
// 1966 JAN 1 =JD 2439126.5 TAI-UTC= 4.3131700 S + (MJD - 39126.) X 0.002592 S
// 1968 FEB 1 =JD 2439887.5 TAI-UTC= 4.2131700 S + (MJD - 39126.) X 0.002592 S
// 1972 JAN 1 =JD 2441317.5 TAI-UTC= 10.0 S + (MJD - 41317.) X 0.0 S
// 1972 JUL 1 =JD 2441499.5 TAI-UTC= 11.0 S + (MJD - 41317.) X 0.0 S
// 1973 JAN 1 =JD 2441683.5 TAI-UTC= 12.0 S + (MJD - 41317.) X 0.0 S
// 1974 JAN 1 =JD 2442048.5 TAI-UTC= 13.0 S + (MJD - 41317.) X 0.0 S
// month as a three letters upper case abbreviation
final StringBuilder builder = new StringBuilder(BLANKS + STORAGE_START);
for (final Month month : Month.values()) {
builder.append(month.getUpperCaseAbbreviation());
builder.append(ALTERNATIVE);
}
builder.delete(builder.length() - 1, builder.length());
builder.append(STORAGE_END);
final String monthField = builder.toString();
dataPattern = Pattern.compile(LINE_START_REGEXP +
STORED_INTEGER_FIELD + monthField + STORED_INTEGER_FIELD +
"\\p{Blank}+=JD" + STORED_REAL_FIELD +
"\\p{Blank}+TAI-UTC=" + STORED_REAL_FIELD +
"\\p{Blank}+S\\p{Blank}+\\+\\p{Blank}+\\(MJD\\p{Blank}+-" + STORED_REAL_FIELD +
"\\p{Blank}*\\)\\p{Blank}+X" + STORED_REAL_FIELD +
"\\p{Blank}*S" + LINE_END_REGEXP);
offsets = new ArrayList<OffsetModel>();
}
/** Get the parsed offsets.
* @return parsed offsets
*/
public List<OffsetModel> getOffsets() {
return offsets;
}
/** {@inheritDoc} */
public boolean stillAcceptsData() {
return offsets.isEmpty();
}
/** Load UTC-TAI offsets entries read from some file.
* <p>The time steps are extracted from some {@code tai-utc.dat} file.
* Since entries are stored in a {@link java.util.SortedMap SortedMap},
* they are chronologically sorted and only one entry remains for a given date.</p>
* @param input data input stream
* @param name name of the file (or zip entry)
* @exception IOException if data can't be read
* @exception ParseException if data can't be parsed
*/
public void loadData(final InputStream input, final String name)
throws IOException, ParseException {
offsets.clear();
// set up a reader for line-oriented file
final BufferedReader reader = new BufferedReader(new InputStreamReader(input, "UTF-8"));
// read all file, ignoring not recognized lines
int lineNumber = 0;
DateComponents lastDate = null;
for (String line = reader.readLine(); line != null; line = reader.readLine()) {
++lineNumber;
// check matching for data lines
final Matcher matcher = dataPattern.matcher(line);
if (matcher.matches()) {
try {
// build an entry from the extracted fields
final DateComponents dc1 = new DateComponents(Integer.parseInt(matcher.group(1)),
Month.parseMonth(matcher.group(2)),
Integer.parseInt(matcher.group(3)));
final DateComponents dc2 = new DateComponents(DateComponents.JULIAN_EPOCH,
(int) FastMath.ceil(Double.parseDouble(matcher.group(4))));
if (!dc1.equals(dc2)) {
throw new OrekitException(OrekitMessages.INCONSISTENT_DATES_IN_IERS_FILE,
name, dc1.getYear(), dc1.getMonth(), dc1.getDay(), dc2.getMJD());
}
if ((lastDate != null) && dc1.compareTo(lastDate) <= 0) {
throw new OrekitException(OrekitMessages.NON_CHRONOLOGICAL_DATES_IN_FILE,
name, lineNumber);
}
lastDate = dc1;
final double offset = Double.parseDouble(matcher.group(5));
final double mjdRef = Double.parseDouble(matcher.group(6));
final double slope = Double.parseDouble(matcher.group(7));
offsets.add(new OffsetModel(dc1, (int) FastMath.rint(mjdRef), offset, slope));
} catch (NumberFormatException nfe) {
throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
lineNumber, name, line);
}
}
}
if (offsets.isEmpty()) {
throw new OrekitException(OrekitMessages.NO_ENTRIES_IN_IERS_UTC_TAI_HISTORY_FILE, name);
}
}
}
}