1 /* Copyright 2002-2025 CS GROUP
2 * Licensed to CS GROUP (CS) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * CS licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.orekit.time;
18
19 import java.io.BufferedReader;
20 import java.io.IOException;
21 import java.io.InputStream;
22 import java.io.InputStreamReader;
23 import java.nio.charset.StandardCharsets;
24 import java.util.ArrayList;
25 import java.util.List;
26 import java.util.regex.Matcher;
27 import java.util.regex.Pattern;
28
29 import org.hipparchus.util.FastMath;
30 import org.orekit.annotation.DefaultDataContext;
31 import org.orekit.data.AbstractSelfFeedingLoader;
32 import org.orekit.data.DataContext;
33 import org.orekit.data.DataProvidersManager;
34 import org.orekit.errors.OrekitException;
35 import org.orekit.errors.OrekitMessages;
36
37 /** Loader for UTC-TAI extracted from LeapSecond file from AGI.
38 * <p>
39 * This class is immutable and hence thread-safe
40 * </p>
41 * @see <a href="ftp://ftp.agi.com/pub/STKData/Astro/LeapSecond.dat">LeapSecond.dat</a>
42 * @author Luc Maisonobe
43 * @since 10.3
44 */
45 public class AGILeapSecondFilesLoader extends AbstractSelfFeedingLoader
46 implements UTCTAIOffsetsLoader {
47
48 /** Default supported files name pattern. */
49 public static final String DEFAULT_SUPPORTED_NAMES = "^LeapSecond\\.dat$";
50
51 /** Number of seconds in one day. */
52 private static final long SEC_PER_DAY = 86400L;
53
54 /** Number of attoseconds in one second. */
55 private static final long ATTOS_PER_NANO = 1000000000L;
56
57 /** Slope conversion factor from seconds per day to nanoseconds per second. */
58 private static final long SLOPE_FACTOR = SEC_PER_DAY * ATTOS_PER_NANO;
59
60 /**
61 * Build a loader for LeapSecond.dat file from AGI. This constructor uses the {@link
62 * DataContext#getDefault() default data context}.
63 *
64 * @param supportedNames regular expression for supported files names
65 * @see #AGILeapSecondFilesLoader(String, DataProvidersManager)
66 */
67 @DefaultDataContext
68 public AGILeapSecondFilesLoader(final String supportedNames) {
69 this(supportedNames, DataContext.getDefault().getDataProvidersManager());
70 }
71
72 /**
73 * Build a loader for LeapSecond.dat file from AGI.
74 *
75 * @param supportedNames regular expression for supported files names
76 * @param manager provides access to the {@code tai-utc.dat} file.
77 */
78 public AGILeapSecondFilesLoader(final String supportedNames,
79 final DataProvidersManager manager) {
80 super(supportedNames, manager);
81 }
82
83 /** {@inheritDoc} */
84 @Override
85 public List<OffsetModel> loadOffsets() {
86 final UtcTaiOffsetLoader parser = new UtcTaiOffsetLoader(new Parser());
87 this.feed(parser);
88 return parser.getOffsets();
89 }
90
91 /** Internal class performing the parsing. */
92 public static class Parser implements UTCTAIOffsetsLoader.Parser {
93
94 /** Regular expression for optional blanks. */
95 private static final String BLANKS = "\\p{Blank}*";
96
97 /** Regular expression for storage start. */
98 private static final String STORAGE_START = "(";
99
100 /** Regular expression for storage end. */
101 private static final String STORAGE_END = ")";
102
103 /** Regular expression for alternative. */
104 private static final String ALTERNATIVE = "|";
105
106 /** Regular expression matching blanks at start of line. */
107 private static final String LINE_START_REGEXP = "^" + BLANKS;
108
109 /** Regular expression matching blanks at end of line. */
110 private static final String LINE_END_REGEXP = BLANKS + "$";
111
112 /** Regular expression matching integers. */
113 private static final String INTEGER_REGEXP = "[-+]?\\p{Digit}+";
114
115 /** Regular expression matching real numbers. */
116 private static final String REAL_REGEXP = "[-+]?(?:\\p{Digit}+(?:\\.\\p{Digit}*)?|\\.\\p{Digit}+)(?:[eE][-+]?\\p{Digit}+)?";
117
118 /** Regular expression matching an integer field to store. */
119 private static final String STORED_INTEGER_FIELD = BLANKS + STORAGE_START + INTEGER_REGEXP + STORAGE_END;
120
121 /** Regular expression matching a real field to store. */
122 private static final String STORED_REAL_FIELD = BLANKS + STORAGE_START + REAL_REGEXP + STORAGE_END;
123
124 /** Data lines pattern. */
125 private final Pattern dataPattern;
126
127 /** Simple constructor.
128 */
129 public Parser() {
130
131 // data lines read:
132 // 28
133 // 1972 JAN 1 2441317.5 10.0 41317. 0.0
134 // 1972 JUL 1 2441499.5 11.0 41317. 0.0
135 // 1973 JAN 1 2441683.5 12.0 41317. 0.0
136 // 1974 JAN 1 2442048.5 13.0 41317. 0.0
137 // 1975 JAN 1 2442413.5 14.0 41317. 0.0
138 // 1976 JAN 1 2442778.5 15.0 41317. 0.0
139 // 1977 JAN 1 2443144.5 16.0 41317. 0.0
140 // 1978 JAN 1 2443509.5 17.0 41317. 0.0
141
142 // month as a three letters upper case abbreviation
143 final StringBuilder builder = new StringBuilder(BLANKS + STORAGE_START);
144 for (final Month month : Month.values()) {
145 builder.append(month.getUpperCaseAbbreviation());
146 builder.append(ALTERNATIVE);
147 }
148 builder.delete(builder.length() - 1, builder.length());
149 builder.append(STORAGE_END);
150 final String monthField = builder.toString();
151
152 dataPattern = Pattern.compile(LINE_START_REGEXP +
153 STORED_INTEGER_FIELD + monthField + STORED_INTEGER_FIELD +
154 BLANKS + STORED_REAL_FIELD +
155 BLANKS + STORED_REAL_FIELD +
156 BLANKS + STORED_REAL_FIELD +
157 BLANKS + STORED_REAL_FIELD +
158 LINE_END_REGEXP);
159
160
161 }
162
163 /** Load UTC-TAI offsets entries read from some file.
164 * <p>The time steps are extracted from some {@code LeapSecond.dat} file.
165 * Since entries are stored in a {@link java.util.SortedMap SortedMap},
166 * they are chronologically sorted and only one entry remains for a given date.</p>
167 * @param input data input stream
168 * @param name name of the file (or zip entry)
169 * @exception IOException if data can't be read
170 */
171 @Override
172 public List<OffsetModel> parse(final InputStream input, final String name)
173 throws IOException {
174
175 final List<OffsetModel> offsets = new ArrayList<>();
176
177 int lineNumber = 0;
178 DateComponents lastDate = null;
179 String line = null;
180 // set up a reader for line-oriented file
181 try (BufferedReader reader = new BufferedReader(new InputStreamReader(input, StandardCharsets.UTF_8))) {
182
183 // read all file, ignoring not recognized lines
184 for (line = reader.readLine(); line != null; line = reader.readLine()) {
185 ++lineNumber;
186
187 // check matching for data lines
188 final Matcher matcher = dataPattern.matcher(line);
189 if (matcher.matches()) {
190
191 // build an entry from the extracted fields
192 final DateComponents dc1 = new DateComponents(Integer.parseInt(matcher.group(1)),
193 Month.parseMonth(matcher.group(2)),
194 Integer.parseInt(matcher.group(3)));
195 final DateComponents dc2 = new DateComponents(DateComponents.JULIAN_EPOCH,
196 (int) FastMath.ceil(Double.parseDouble(matcher.group(4))));
197 if (!dc1.equals(dc2)) {
198 throw new OrekitException(OrekitMessages.INCONSISTENT_DATES_IN_IERS_FILE,
199 name, dc1.getYear(), dc1.getMonth(), dc1.getDay(), dc2.getMJD());
200 }
201
202 if (lastDate != null && dc1.compareTo(lastDate) <= 0) {
203 throw new OrekitException(OrekitMessages.NON_CHRONOLOGICAL_DATES_IN_FILE,
204 name, lineNumber);
205 }
206 lastDate = dc1;
207
208 final double mjdRef = Double.parseDouble(matcher.group(6));
209 offsets.add(new OffsetModel(dc1, (int) FastMath.rint(mjdRef),
210 TimeOffset.parse(matcher.group(5)),
211 (int) (TimeOffset.parse(matcher.group(7)).getAttoSeconds() / SLOPE_FACTOR)));
212
213 }
214 }
215
216 } catch (NumberFormatException nfe) {
217 throw new OrekitException(OrekitMessages.UNABLE_TO_PARSE_LINE_IN_FILE,
218 lineNumber, name, line);
219 }
220
221 if (offsets.isEmpty()) {
222 throw new OrekitException(OrekitMessages.NO_ENTRIES_IN_IERS_UTC_TAI_HISTORY_FILE, name);
223 }
224
225 return offsets;
226
227 }
228
229 }
230
231 }