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Enhance TZDB compiler to better match spec #786

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Sep 12, 2024
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Enhance TZDB compiler to better match spec #786

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6 changes: 6 additions & 0 deletions src/changes/changes.xml
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,12 @@
<body>

<!-- types are add, fix, remove, update -->
<release version="2.13.0" date="SNAPSHOT" description="v2.13.0">
<action dev="jodastephen" type="fix">
Enhance the parser to better match specification of zic.
Fixes #785.
</action>
</release>
<release version="2.12.7" date="2024-02-04" description="v2.12.7">
<action dev="jodastephen" type="update">
DateTimeZone data updated to version 2024agtz.
Expand Down
171 changes: 141 additions & 30 deletions src/main/java/org/joda/time/tz/ZoneInfoCompiler.java
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Original file line number Diff line number Diff line change
Expand Up @@ -26,16 +26,18 @@
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Locale;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import java.util.StringTokenizer;
import java.util.TreeMap;

import org.joda.time.Chronology;
import org.joda.time.DateTime;
import org.joda.time.DateTimeField;
import org.joda.time.DateTimeZone;
import org.joda.time.LocalDate;
import org.joda.time.MutableDateTime;
Expand All @@ -61,10 +63,64 @@
* @since 1.0
*/
public class ZoneInfoCompiler {
// SPEC: https://man7.org/linux/man-pages/man8/zic.8.html#FILES
// Note that we match a subset of the spec, as actually seen in TZDB files

static DateTimeOfYear cStartOfYear;

static Chronology cLenientISO;

// SPEC: A name can be abbreviated by omitting all but an initial prefix; any
// abbreviation must be unambiguous in context.
static final Set<String> RULE_LOOKUP = expand("rule", "r");
static final Set<String> ZONE_LOOKUP = expand("zone", "z");
static final Set<String> LINK_LOOKUP = expand("link", "l");
static final Set<String> MIN_YEAR_LOOKUP = expand("minimum", "mi");
static final Set<String> MAX_YEAR_LOOKUP = expand("maximum", "ma");
static final Set<String> ONLY_YEAR_LOOKUP = expand("only", "o");
static final Map<String, Integer> MONTH_LOOKUP = new HashMap<String, Integer>();
static {
put(expand("january", "ja"), 1, MONTH_LOOKUP);
put(expand("february", "f"), 2, MONTH_LOOKUP);
put(expand("march", "mar"), 3, MONTH_LOOKUP);
put(expand("april", "ap"), 4, MONTH_LOOKUP);
put(expand("may", "may"), 5, MONTH_LOOKUP);
put(expand("june", "jun"), 6, MONTH_LOOKUP);
put(expand("july", "jul"), 7, MONTH_LOOKUP);
put(expand("august", "au"), 8, MONTH_LOOKUP);
put(expand("september", "s"), 9, MONTH_LOOKUP);
put(expand("october", "o"), 10, MONTH_LOOKUP);
put(expand("november", "n"), 11, MONTH_LOOKUP);
put(expand("december", "d"), 12, MONTH_LOOKUP);
}
static final Map<String, Integer> DOW_LOOKUP = new HashMap<String, Integer>();
static {
put(expand("monday", "m"), 1, DOW_LOOKUP);
put(expand("tuesday", "tu"), 2, DOW_LOOKUP);
put(expand("wednesday", "w"), 3, DOW_LOOKUP);
put(expand("thursday", "th"), 4, DOW_LOOKUP);
put(expand("friday", "f"), 5, DOW_LOOKUP);
put(expand("saturday", "sa"), 6, DOW_LOOKUP);
put(expand("sunday", "su"), 7, DOW_LOOKUP);
}

private static void put(Set<String> strs, int value, Map<String, Integer> map) {
for (Iterator<String> it = strs.iterator(); it.hasNext();) {
map.put(it.next(), value);
}
}

private static Set<String> expand(String whole, String shortest) {
Set<String> set = new HashSet<String>();
String code = whole;
while (!code.equals(shortest)) {
set.add(code);
code = code.substring(0, code.length() - 1);
}
set.add(code);
return set;
}

//-----------------------------------------------------------------------
/**
* Launches the ZoneInfoCompiler tool.
Expand Down Expand Up @@ -200,32 +256,43 @@ static void writeZoneInfoMap(DataOutputStream dout, Map<String, DateTimeZone> zi
}

static int parseYear(String str, int def) {
str = str.toLowerCase(Locale.ENGLISH);
if (str.equals("minimum") || str.equals("min")) {
String lower = str.toLowerCase(Locale.ENGLISH);
if (MIN_YEAR_LOOKUP.contains(lower)) {
return Integer.MIN_VALUE;
} else if (str.equals("maximum") || str.equals("max")) {
} else if (MAX_YEAR_LOOKUP.contains(lower)) {
return Integer.MAX_VALUE;
} else if (str.equals("only")) {
} else if (ONLY_YEAR_LOOKUP.contains(lower)) {
return def;
}
return Integer.parseInt(str);
}

static int parseMonth(String str) {
DateTimeField field = ISOChronology.getInstanceUTC().monthOfYear();
return field.get(field.set(0, str, Locale.ENGLISH));
Integer value = MONTH_LOOKUP.get(str.toLowerCase(Locale.ENGLISH));
if (value == null) {
throw new IllegalArgumentException("Unknown month: " + str);
}
return value;
}

static int parseDayOfWeek(String str) {
DateTimeField field = ISOChronology.getInstanceUTC().dayOfWeek();
return field.get(field.set(0, str, Locale.ENGLISH));
Integer value = DOW_LOOKUP.get(str.toLowerCase(Locale.ENGLISH));
if (value == null) {
throw new IllegalArgumentException("Unknown day-of-week: " + str);
}
return value;
}

static String parseOptional(String str) {
return (str.equals("-")) ? null : str;
}

static int parseTime(String str) {
// SPEC: (see 'AT' section)
// NOTE: negative offsets, and offsets beyond 24:00, are not supported
if (str.equals("-")) {
return 0;
}
DateTimeFormatter p = ISODateTimeFormat.hourMinuteSecondFraction();
MutableDateTime mdt = new MutableDateTime(0, getLenientISOChronology());
int pos = 0;
Expand All @@ -244,6 +311,10 @@ static int parseTime(String str) {
}

static char parseZoneChar(char c) {
// SPEC: Any of these forms may be followed by the letter w if the given time is local or “wall clock” time,
// s if the given time is standard time without any adjustment for daylight saving,
// or u (or g or z) if the given time is universal time;
// in the absence of an indicator, local (wall clock) time is assumed.
switch (c) {
case 's': case 'S':
// Standard time
Expand Down Expand Up @@ -502,19 +573,28 @@ public void parseDataFile(BufferedReader in, boolean backward) throws IOExceptio
Zone zone = null;
String line;
while ((line = in.readLine()) != null) {
// SPEC: Leading and trailing white space on input lines is ignored.
String trimmed = line.trim();

// SPEC: An unquoted sharp character (#) in the input
// introduces a comment which extends to the end of the line the
// sharp character appears on.
// Any line that is blank (after comment stripping) is ignored
// (Note that we do not support quoted fields)
if (trimmed.length() == 0 || trimmed.charAt(0) == '#') {
continue;
}

int index = line.indexOf('#');
if (index >= 0) {
line = line.substring(0, index);
}

//System.out.println(line);

StringTokenizer st = new StringTokenizer(line, " \t");
// SPEC: Fields are separated from one
// another by one or more white space characters. The white space
// characters are space, form feed, carriage return, newline, tab,
// and vertical tab.
StringTokenizer st = new StringTokenizer(line, " \f\r\t\u000b");

if (Character.isWhitespace(line.charAt(0)) && st.hasMoreTokens()) {
if (zone != null) {
Expand All @@ -529,9 +609,14 @@ public void parseDataFile(BufferedReader in, boolean backward) throws IOExceptio
zone = null;
}

// SPEC: Names must be in English and are case insensitive. They appear
// in several contexts, and include month and weekday names and
// keywords such as maximum, only, Rolling, and Zone. A name can be
// abbreviated by omitting all but an initial prefix; any
// abbreviation must be unambiguous in context.
if (st.hasMoreTokens()) {
String token = st.nextToken();
if (token.equalsIgnoreCase("Rule")) {
String token = st.nextToken().toLowerCase(Locale.ENGLISH);
if (RULE_LOOKUP.contains(token)) {
Rule r = new Rule(st);
RuleSet rs = iRuleSets.get(r.iName);
if (rs == null) {
Expand All @@ -540,12 +625,12 @@ public void parseDataFile(BufferedReader in, boolean backward) throws IOExceptio
} else {
rs.addRule(r);
}
} else if (token.equalsIgnoreCase("Zone")) {
} else if (ZONE_LOOKUP.contains(token)) {
if (st.countTokens() < 4) {
throw new IllegalArgumentException("Attempting to create a Zone from an incomplete tokenizer");
}
zone = new Zone(st);
} else if (token.equalsIgnoreCase("Link")) {
} else if (LINK_LOOKUP.contains(token)) {
String real = st.nextToken();
String alias = st.nextToken();
// links in "backward" are deprecated names
Expand All @@ -569,6 +654,7 @@ public void parseDataFile(BufferedReader in, boolean backward) throws IOExceptio
}
}

// ScopedForTesting
static class DateTimeOfYear {
public final int iMonthOfYear;
public final int iDayOfMonth;
Expand Down Expand Up @@ -599,7 +685,7 @@ static class DateTimeOfYear {

if (st.hasMoreTokens()) {
String str = st.nextToken();
if (str.startsWith("last")) {
if (str.toLowerCase(Locale.ENGLISH).startsWith("last")) {
day = -1;
dayOfWeek = parseDayOfWeek(str.substring(4));
advance = false;
Expand Down Expand Up @@ -627,6 +713,8 @@ static class DateTimeOfYear {
}
}

// the SPEC treats time as a duration from 00:00, whereas we parse it as a time
// as such, we cannot handle negative or times beyond 24:00
if (st.hasMoreTokens()) {
str = st.nextToken();
zoneChar = parseZoneChar(str.charAt(str.length() - 1));
Expand Down Expand Up @@ -711,7 +799,8 @@ public String toString() {
}
}

private static class Rule {
// ScopedForTesting
static class Rule {
public final String iName;
public final int iFromYear;
public final int iToYear;
Expand Down Expand Up @@ -760,7 +849,9 @@ public void addRecurring(DateTimeZoneBuilder builder, int negativeSave, String n
iDateTimeOfYear.addRecurring(builder, nameKey, saveMillis, iFromYear, iToYear);
}

private static String formatName(String nameFormat, int saveMillis, String letterS) {
// ScopedForTesting
static String formatName(String nameFormat, int saveMillis, String letterS) {
// SPEC: Alternatively, a slash (/) separates standard and daylight abbreviations.
int index = nameFormat.indexOf('/');
if (index > 0) {
if (saveMillis == 0) {
Expand All @@ -770,19 +861,39 @@ private static String formatName(String nameFormat, int saveMillis, String lette
return nameFormat.substring(index + 1).intern();
}
}
// SPEC: The pair of characters %s is used to show where the “variable part” of the time zone abbreviation goes.
// LETTER column: Gives the “variable part” (for example, the “S” or “D” in “EST” or “EDT”) of time zone
// abbreviations to be used when this rule is in effect. If this field is “-”, the variable part is null.
// (the "-" was removed in parsing)
index = nameFormat.indexOf("%s");
if (index < 0) {
return nameFormat;
}
String left = nameFormat.substring(0, index);
String right = nameFormat.substring(index + 2);
String name;
if (letterS == null) {
name = left.concat(right);
} else {
name = left + letterS + right;
if (index >= 0) {
String left = nameFormat.substring(0, index);
String right = nameFormat.substring(index + 2);
String name = left + (letterS == null ? "" : letterS) + right;
return name.intern();
}
return name.intern();
// SPEC: Alternatively, a format can use the pair of characters %z to stand for the UT
// offset in the form ±hh, ±hhmm, or ±hhmmss, using the shortest form that does not lose information,
// where hh, mm, and ss are the hours, minutes, and seconds east (+) or west (-) of UT.
if (nameFormat.equals("%z")) {
String sign = saveMillis < 0 ? "-" : "+";
int saveSecs = Math.abs(saveMillis) / 1000;
int hours = saveSecs / 3600;
int mins = ((saveSecs / 60) % 60);
int secs = (saveSecs % 60);
if (secs == 0) {
if (mins == 0) {
return sign + twoDigitString(hours);
}
return sign + twoDigitString(hours) + twoDigitString(mins);
}
return sign + twoDigitString(hours) + twoDigitString(mins) + twoDigitString(secs);
}
return nameFormat;
}

private static String twoDigitString(int value) {
return Integer.toString(value + 100).substring(1);
}

@Override
Expand Down
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