re PR libgcj/17002 (java.util.TimeZone.getDefault() is broken)

libjava/
	PR libgcj/17002
	PR classpath/28550
	* java/util/VMTimeZone.java (getDefaultTimeZoneId): To read
	/etc/localtime, use ZoneInfo.readTZFile instead of
	VMTimeZone.readtzFile.  Get better timezone name for /etc/localtime,
	either if it is a symlink or through /etc/sysconfig/clock.
	(readSysconfigClockFile): New static method.
	(readtzFile): Removed.
	* java/lang/System.java: Add gnu.java.util.zoneinfo.dir to comments.
	* posix.cc (_Jv_platform_initProperties): Set
	gnu.java.util.zoneinfo.dir.
	* sources.am (gnu_java_util_source_files): Add
	classpath/gnu/java/util/ZoneInfo.java.
	* Makefile.in: Regenerated.
	* java/util/VMTimeZone.h: Regenerated.
	* java/util/TimeZone.h: Regenerated.
	* gnu/java/util/ZoneInfo.h: Generated.
libjava/classpath/
	* java/util/Date.java (parse): Properly parse 09:01:02 as
	hours/minutes/seconds, not as hours/minutes/year.
	* java/util/SimpleTimeZone.java (SimpleTimeZone): Simplify
	{start,end}TimeMode constructor by calling shorter constructor,
	set {start,end}TimeMode fields after it returns.
	(setStartRule): Don't adjust startTime into WALL_TIME.  Set
	startTimeMode to WALL_TIME.
	(endStartRule): Similarly.
	(getOffset): Handle properly millis + dstOffset overflowing into the
	next day.  Adjust startTime resp. endTime based on startTimeMode
	resp. endTimeMode.
	* java/util/TimeZone.java (zoneinfo_dir, availableIDs, aliases0): New
	static fields.
	(timezones): Remove synchronized keyword.  Set zoneinfo_dir.
	If non-null, set up aliases0 and don't put anything into
	timezones0.
	(defaultZone): Call getTimeZone instead of timezones().get.
	(getDefaultTimeZone): Fix parsing of EST5 or EST5EDT6.  Use
	getTimeZoneInternal instead of timezones().get.
	(parseTime): Parse correctly hour:minute.
	(getTimeZoneInternal): New private method.
	(getTimeZone): Do the custom ID checking first, canonicalize
	ID for custom IDs as required by documentation.  Call
	getTimeZoneInternal to handle the rest.
	(getAvailableIDs(int)): Add locking.  Handle zoneinfo_dir != null.
	(getAvailableIDs(File,String,ArrayList)): New private method.
	(getAvailableIDs()): Add locking.  Handle zoneinfo_dir != null.
	* gnu/java/util/ZoneInfo.java: New file.

From-SVN: r122229

3 files changed, 317 insertions, 126 deletions

diff --git a/libjava/classpath/java/util/Date.java b/libjava/classpath/java/util/Date.java
index 5c43bf3..f481753 100644
--- a/libjava/classpath/java/util/Date.java
+++ b/libjava/classpath/java/util/Date.java
@@ -754,6 +754,7 @@ public class Date
 	  }
 	else if (firstch >= '0' && firstch <= '9')
 	  {
+	    int lastPunct = -1;
 	    while (tok != null && tok.length() > 0)
 	      {
 		int punctOffset = tok.length();
@@ -791,6 +792,13 @@ public class Date
 		    else
 		      minute = num;
 		  }
+		else if (lastPunct == ':' && hour >= 0 && (minute < 0 || second < 0))
+		  {
+		    if (minute < 0)
+		      minute = num;
+		    else
+		      second = num;
+		  }
 	        else if ((num >= 70
 			  && (punct == ' ' || punct == ','
 			      || punct == '/' || punct < 0))
@@ -828,6 +836,7 @@ public class Date
 		  tok = null;
 		else
 		  tok = tok.substring(punctOffset + 1);
+		lastPunct = punct;
 	      }
 	  }
 	else if (firstch >= 'A' && firstch <= 'Z')
diff --git a/libjava/classpath/java/util/SimpleTimeZone.java b/libjava/classpath/java/util/SimpleTimeZone.java
index d94f89a..14821ba 100644
--- a/libjava/classpath/java/util/SimpleTimeZone.java
+++ b/libjava/classpath/java/util/SimpleTimeZone.java
@@ -1,5 +1,6 @@
 /* java.util.SimpleTimeZone
-   Copyright (C) 1998, 1999, 2000, 2003, 2004, 2005  Free Software Foundation, Inc.
+   Copyright (C) 1998, 1999, 2000, 2003, 2004, 2005, 2007
+   Free Software Foundation, Inc.
 
 This file is part of GNU Classpath.
 
@@ -141,8 +142,8 @@ public class SimpleTimeZone extends TimeZone
 
   /**
    * This variable specifies the time of change to daylight savings.
-   * This time is given in milliseconds after midnight local
-   * standard time.
+   * This time is given in milliseconds after midnight in startTimeMode
+   * chosen time mode.
    * @serial
    */
   private int startTime;
@@ -187,8 +188,8 @@ public class SimpleTimeZone extends TimeZone
 
   /**
    * This variable specifies the time of change back to standard time.
-   * This time is given in milliseconds after midnight local
-   * standard time.
+   * This time is given in milliseconds after midnight in endTimeMode
+   * chosen time mode.
    * @serial
    */
   private int endTime;
@@ -380,24 +381,17 @@ public class SimpleTimeZone extends TimeZone
                         int endDayOfWeekInMonth, int endDayOfWeek,
                         int endTime, int endTimeMode, int dstSavings)
   {
-    this.rawOffset = rawOffset;
-    setID(id);
-    useDaylight = true;
+    this(rawOffset, id, startMonth, startDayOfWeekInMonth, startDayOfWeek,
+	 startTime, endMonth, endDayOfWeekInMonth, endDayOfWeek, endTime);
 
     if (startTimeMode < WALL_TIME || startTimeMode > UTC_TIME)
       throw new IllegalArgumentException("startTimeMode must be one of WALL_TIME, STANDARD_TIME, or UTC_TIME");
     if (endTimeMode < WALL_TIME || endTimeMode > UTC_TIME)
       throw new IllegalArgumentException("endTimeMode must be one of WALL_TIME, STANDARD_TIME, or UTC_TIME");
-    this.startTimeMode = startTimeMode;
-    this.endTimeMode = endTimeMode;
-
-    setStartRule(startMonth, startDayOfWeekInMonth, startDayOfWeek, startTime);
-    setEndRule(endMonth, endDayOfWeekInMonth, endDayOfWeek, endTime);
-    if (startMonth == endMonth)
-      throw new IllegalArgumentException("startMonth and endMonth must be different");
-    this.startYear = 0;
 
     this.dstSavings = dstSavings;
+    this.startTimeMode = startTimeMode;
+    this.endTimeMode = endTimeMode;
   }
 
   /**
@@ -477,12 +471,8 @@ public class SimpleTimeZone extends TimeZone
     this.startMonth = month;
     this.startDay = day;
     this.startDayOfWeek = Math.abs(dayOfWeek);
-    if (this.startTimeMode == WALL_TIME || this.startTimeMode == STANDARD_TIME)
-      this.startTime = time;
-    else
-      // Convert from UTC to STANDARD
-      this.startTime = time + this.rawOffset;
-    useDaylight = true;
+    this.startTime = time;
+    this.startTimeMode = WALL_TIME;
   }
 
   /**
@@ -513,24 +503,10 @@ public class SimpleTimeZone extends TimeZone
   public void setStartRule(int month, int day, int dayOfWeek, int time,
                            boolean after)
   {
-    // FIXME: XXX: Validate that checkRule and offset processing work with on
-    // or before mode.
-    this.startDay = after ? Math.abs(day) : -Math.abs(day);
-    this.startDayOfWeek = after ? Math.abs(dayOfWeek) : -Math.abs(dayOfWeek);
-    this.startMode = (dayOfWeek != 0)
-                     ? (after ? DOW_GE_DOM_MODE : DOW_LE_DOM_MODE)
-                     : checkRule(month, day, dayOfWeek);
-    this.startDay = Math.abs(this.startDay);
-    this.startDayOfWeek = Math.abs(this.startDayOfWeek);
-
-    this.startMonth = month;
-
-    if (this.startTimeMode == WALL_TIME || this.startTimeMode == STANDARD_TIME)
-      this.startTime = time;
+    if (after)
+      setStartRule(month, day, -dayOfWeek, time);
     else
-      // Convert from UTC to STANDARD
-      this.startTime = time + this.rawOffset;
-    useDaylight = true;
+      setStartRule(month, -day, -dayOfWeek, time);
   }
 
   /**
@@ -570,14 +546,8 @@ public class SimpleTimeZone extends TimeZone
     this.endMonth = month;
     this.endDay = day;
     this.endDayOfWeek = Math.abs(dayOfWeek);
-    if (this.endTimeMode == WALL_TIME)
-      this.endTime = time;
-    else if (this.endTimeMode == STANDARD_TIME)
-      // Convert from STANDARD to DST
-      this.endTime = time + this.dstSavings;
-    else
-      // Convert from UTC to DST
-      this.endTime = time + this.rawOffset + this.dstSavings;
+    this.endTime = time;
+    this.endTimeMode = WALL_TIME;
     useDaylight = true;
   }
 
@@ -607,27 +577,10 @@ public class SimpleTimeZone extends TimeZone
   public void setEndRule(int month, int day, int dayOfWeek, int time,
                          boolean after)
   {
-    // FIXME: XXX: Validate that checkRule and offset processing work with on
-    // or before mode.
-    this.endDay = after ? Math.abs(day) : -Math.abs(day);
-    this.endDayOfWeek = after ? Math.abs(dayOfWeek) : -Math.abs(dayOfWeek);
-    this.endMode = (dayOfWeek != 0)
-                   ? (after ? DOW_GE_DOM_MODE : DOW_LE_DOM_MODE)
-                   : checkRule(month, day, dayOfWeek);
-    this.endDay = Math.abs(this.endDay);
-    this.endDayOfWeek = Math.abs(endDayOfWeek);
-
-    this.endMonth = month;
-
-    if (this.endTimeMode == WALL_TIME)
-      this.endTime = time;
-    else if (this.endTimeMode == STANDARD_TIME)
-      // Convert from STANDARD to DST
-      this.endTime = time + this.dstSavings;
+    if (after)
+      setEndRule(month, day, -dayOfWeek, time);
     else
-      // Convert from UTC to DST
-      this.endTime = time + this.rawOffset + this.dstSavings;
-    useDaylight = true;
+      setEndRule(month, -day, -dayOfWeek, time);
   }
 
   /**
@@ -688,16 +641,37 @@ public class SimpleTimeZone extends TimeZone
     int daylightSavings = 0;
     if (useDaylight && era == GregorianCalendar.AD && year >= startYear)
       {
+	int orig_year = year;
+	int time = startTime + (startTimeMode == UTC_TIME ? rawOffset : 0);
 	// This does only work for Gregorian calendars :-(
 	// This is mainly because setStartYear doesn't take an era.
 	boolean afterStart = ! isBefore(year, month, day, dayOfWeek, millis,
 	                                startMode, startMonth, startDay,
-	                                startDayOfWeek, startTime);
-	boolean beforeEnd = isBefore(year, month, day, dayOfWeek,
-				     millis + dstSavings,
-	                             endMode, endMonth, endDay, endDayOfWeek,
-	                             endTime);
-
+					startDayOfWeek, time);
+	millis += dstSavings;
+	if (millis >= 24 * 60 * 60 * 1000)
+	  {
+	    millis -= 24 * 60 * 60 * 1000;
+	    dayOfWeek = (dayOfWeek % 7) + 1;
+	    if (++day > daysInMonth)
+	      {
+		day = 1;
+		if (month++ == Calendar.DECEMBER)
+		  {
+		    month = Calendar.JANUARY;
+		    year++;
+		  }
+	      }
+	  }
+	time = endTime + (endTimeMode == UTC_TIME ? rawOffset : 0);
+	if (endTimeMode != WALL_TIME)
+	  time += dstSavings;
+	boolean beforeEnd = isBefore(year, month, day, dayOfWeek, millis,
+				     endMode, endMonth, endDay, endDayOfWeek,
+				     time);
+
+	if (year != orig_year)
+	  afterStart = false;
 	if (startMonth < endMonth)
 	  // use daylight savings, if the date is after the start of
 	  // savings, and before the end of savings.
diff --git a/libjava/classpath/java/util/TimeZone.java b/libjava/classpath/java/util/TimeZone.java
index a253561..cede9fc 100644
--- a/libjava/classpath/java/util/TimeZone.java
+++ b/libjava/classpath/java/util/TimeZone.java
@@ -39,6 +39,9 @@ exception statement from your version. */
 
 package java.util;
 
+import gnu.classpath.SystemProperties;
+import gnu.java.util.ZoneInfo;
+import java.io.File;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
 import java.text.DateFormatSymbols;
@@ -115,7 +118,7 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
 		
 		// Fall back on GMT.
 		if (zone == null)
-		  zone = (TimeZone) timezones().get("GMT");
+		  zone = getTimeZone ("GMT");
 		
 		return zone;
 	      }
@@ -128,6 +131,22 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
   private static final long serialVersionUID = 3581463369166924961L;
 
   /**
+   * Flag whether zoneinfo data should be used,
+   * otherwise builtin timezone data will be provided.
+   */
+  private static String zoneinfo_dir;
+
+  /**
+   * Cached copy of getAvailableIDs().
+   */
+  private static String[] availableIDs = null;
+
+  /**
+   * JDK 1.1.x compatibility aliases.
+   */
+  private static HashMap aliases0;
+
+  /**
    * HashMap for timezones by ID.  
    */
   private static HashMap timezones0;
@@ -135,13 +154,55 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
    * it is not needed: 
    */
   // Package-private to avoid a trampoline.
-  static synchronized HashMap timezones()
+  static HashMap timezones()
   {
     if (timezones0 == null) 
       {
 	HashMap timezones = new HashMap();
 	timezones0 = timezones;
 
+	zoneinfo_dir = SystemProperties.getProperty("gnu.java.util.zoneinfo.dir");
+	if (zoneinfo_dir != null && !new File(zoneinfo_dir).isDirectory())
+	  zoneinfo_dir = null;
+
+	if (zoneinfo_dir != null)
+	  {
+	    aliases0 = new HashMap();
+
+	    // These deprecated aliases for JDK 1.1.x compatibility
+	    // should take precedence over data files read from
+	    // /usr/share/zoneinfo.
+	    aliases0.put("ACT", "Australia/Darwin");
+	    aliases0.put("AET", "Australia/Sydney");
+	    aliases0.put("AGT", "America/Argentina/Buenos_Aires");
+	    aliases0.put("ART", "Africa/Cairo");
+	    aliases0.put("AST", "America/Juneau");
+	    aliases0.put("BST", "Asia/Colombo");
+	    aliases0.put("CAT", "Africa/Gaborone");
+	    aliases0.put("CNT", "America/St_Johns");
+	    aliases0.put("CST", "CST6CDT");
+	    aliases0.put("CTT", "Asia/Brunei");
+	    aliases0.put("EAT", "Indian/Comoro");
+	    aliases0.put("ECT", "CET");
+	    aliases0.put("EST", "EST5EDT");
+	    aliases0.put("EST5", "EST5EDT");
+	    aliases0.put("IET", "EST5EDT");
+	    aliases0.put("IST", "Asia/Calcutta");
+	    aliases0.put("JST", "Asia/Seoul");
+	    aliases0.put("MIT", "Pacific/Niue");
+	    aliases0.put("MST", "MST7MDT");
+	    aliases0.put("MST7", "MST7MDT");
+	    aliases0.put("NET", "Indian/Mauritius");
+	    aliases0.put("NST", "Pacific/Auckland");
+	    aliases0.put("PLT", "Indian/Kerguelen");
+	    aliases0.put("PNT", "MST7MDT");
+	    aliases0.put("PRT", "America/Anguilla");
+	    aliases0.put("PST", "PST8PDT");
+	    aliases0.put("SST", "Pacific/Ponape");
+	    aliases0.put("VST", "Asia/Bangkok");
+	    return timezones;
+	  }
+
 	TimeZone tz;
 	// Automatically generated by scripts/timezones.pl
 	// XXX - Should we read this data from a file?
@@ -887,7 +948,6 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
   static TimeZone getDefaultTimeZone(String sysTimeZoneId)
   {
     String stdName = null;
-    String dstName;
     int stdOffs;
     int dstOffs;
     try
@@ -900,14 +960,14 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
 
 	// get std
 	do
-	  c = sysTimeZoneId.charAt(index++);
+	  c = sysTimeZoneId.charAt(index);
 	while (c != '+' && c != '-' && c != ',' && c != ':'
-	       && ! Character.isDigit(c) && c != '\0' && index < idLength);
+	       && ! Character.isDigit(c) && c != '\0' && ++index < idLength);
 
 	if (index >= idLength)
-	  return (TimeZone)timezones().get(sysTimeZoneId);
+	  return getTimeZoneInternal(sysTimeZoneId);
 
-	stdName = sysTimeZoneId.substring(0, --index);
+	stdName = sysTimeZoneId.substring(0, index);
 	prevIndex = index;
 
 	// get the std offset
@@ -938,7 +998,7 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
 	if (index >= idLength)
 	  {
 	    // Do we have an existing timezone with that name and offset?
-	    TimeZone tz = (TimeZone) timezones().get(stdName);
+	    TimeZone tz = getTimeZoneInternal(stdName);
 	    if (tz != null)
 	      if (tz.getRawOffset() == stdOffs)
 		return tz;
@@ -949,16 +1009,16 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
 
 	// get dst
 	do
-	  c = sysTimeZoneId.charAt(index++);
+	  c = sysTimeZoneId.charAt(index);
 	while (c != '+' && c != '-' && c != ',' && c != ':'
-	       && ! Character.isDigit(c) && c != '\0' && index < idLength);
+	       && ! Character.isDigit(c) && c != '\0' && ++index < idLength);
 
 	// Done yet? (Format: std offset dst)
 	if (index >= idLength)
 	  {
 	    // Do we have an existing timezone with that name and offset 
 	    // which has DST?
-	    TimeZone tz = (TimeZone) timezones().get(stdName);
+	    TimeZone tz = getTimeZoneInternal(stdName);
 	    if (tz != null)
 	      if (tz.getRawOffset() == stdOffs && tz.useDaylightTime())
 		return tz;
@@ -968,7 +1028,6 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
 	  }
 
 	// get the dst offset
-	dstName = sysTimeZoneId.substring(prevIndex, --index);
 	prevIndex = index;
 	do
 	  c = sysTimeZoneId.charAt(index++);
@@ -1005,7 +1064,7 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
 	if (index >= idLength)
 	  {
 	    // Time Zone existing with same name, dst and offsets?
-	    TimeZone tz = (TimeZone) timezones().get(stdName);
+	    TimeZone tz = getTimeZoneInternal(stdName);
 	    if (tz != null)
 	      if (tz.getRawOffset() == stdOffs && tz.useDaylightTime()
 	          && tz.getDSTSavings() == (dstOffs - stdOffs))
@@ -1171,10 +1230,10 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
 	break;
       else
 	i++;
+    millis += 60 * 1000 * Integer.parseInt(time.substring(iprev, i));
     if (i >= time.length())
       return millis;
 
-    millis += 60 * 1000 * Integer.parseInt(time.substring(iprev, i));
     millis += 1000 * Integer.parseInt(time.substring(++i));
     return millis;
   }
@@ -1406,30 +1465,67 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
    * @return The time zone for the identifier or GMT, if no such time
    * zone exists.
    */
-  // FIXME: XXX: JCL indicates this and other methods are synchronized.
-  public static TimeZone getTimeZone(String ID)
+  private static TimeZone getTimeZoneInternal(String ID)
   {
     // First check timezones hash
-    TimeZone tz = (TimeZone) timezones().get(ID);
-    if (tz != null)
+    TimeZone tz = null;
+    TimeZone tznew = null;
+    for (int pass = 0; pass < 2; pass++)
       {
-	if (tz.getID().equals(ID))
-	  return tz;
-
-	// We always return a timezone with the requested ID.
-	// This is the same behaviour as with JDK1.2.
-	tz = (TimeZone) tz.clone();
-	tz.setID(ID);
-	// We also save the alias, so that we return the same
-	// object again if getTimeZone is called with the same
-	// alias.
-	timezones().put(ID, tz);
-	return tz;
+	synchronized (TimeZone.class)
+	  {
+	    tz = (TimeZone) timezones().get(ID);
+	    if (tz != null)
+	      {
+		if (!tz.getID().equals(ID))
+		  {
+		    // We always return a timezone with the requested ID.
+		    // This is the same behaviour as with JDK1.2.
+		    tz = (TimeZone) tz.clone();
+		    tz.setID(ID);
+		    // We also save the alias, so that we return the same
+		    // object again if getTimeZone is called with the same
+		    // alias.
+		    timezones().put(ID, tz);
+		  }
+		return tz;
+	      }
+	    else if (tznew != null)
+	      {
+		timezones().put(ID, tznew);
+		return tznew;
+	      }
+	  }
+
+	if (pass == 1 || zoneinfo_dir == null)
+	  return null;
+
+	// aliases0 is never changing after first timezones(), so should
+	// be safe without synchronization.
+	String zonename = (String) aliases0.get(ID);
+	if (zonename == null)
+	  zonename = ID;
+
+	// Read the file outside of the critical section, it is expensive.
+	tznew = ZoneInfo.readTZFile (ID, zoneinfo_dir
+				     + File.separatorChar + zonename);
+	if (tznew == null)
+	  return null;
       }
 
-    // See if the ID is really a GMT offset form.
-    // Note that GMT is in the table so we know it is different.
-    if (ID.startsWith("GMT"))
+    return null;
+  }
+
+  /**
+   * Gets the TimeZone for the given ID.
+   * @param ID the time zone identifier.
+   * @return The time zone for the identifier or GMT, if no such time
+   * zone exists.
+   */
+  public static TimeZone getTimeZone(String ID)
+  {
+    // Check for custom IDs first
+    if (ID.startsWith("GMT") && ID.length() > 3)
       {
 	int pos = 3;
 	int offset_direction = 1;
@@ -1474,8 +1570,20 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
 		  }
 	      }
 
-	    return new SimpleTimeZone((hour * (60 * 60 * 1000) +
-				       minute * (60 * 1000))
+	    // Custom IDs have to be normalized
+	    StringBuffer sb = new StringBuffer(9);
+	    sb.append("GMT");
+
+	    sb.append(offset_direction >= 0 ? '+' : '-');
+	    sb.append((char) ('0' + hour / 10));
+	    sb.append((char) ('0' + hour % 10));
+	    sb.append(':');
+	    sb.append((char) ('0' + minute / 10));
+	    sb.append((char) ('0' + minute % 10));
+	    ID = sb.toString();
+
+	    return new SimpleTimeZone((hour * (60 * 60 * 1000)
+				       + minute * (60 * 1000))
 				      * offset_direction, ID);
 	  }
 	catch (NumberFormatException e)
@@ -1483,8 +1591,11 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
 	  }
       }
 
-    // Finally, return GMT per spec
-    return getTimeZone("GMT");
+    TimeZone tz = getTimeZoneInternal(ID);
+    if (tz != null)
+      return tz;
+
+    return new SimpleTimeZone(0, "GMT");
   }
 
   /**
@@ -1497,37 +1608,134 @@ public abstract class TimeZone implements java.io.Serializable, Cloneable
    */
   public static String[] getAvailableIDs(int rawOffset)
   {
+    synchronized (TimeZone.class)
+      {
+	HashMap h = timezones();
+	int count = 0;
+	if (zoneinfo_dir == null)
+	  {
+	    Iterator iter = h.entrySet().iterator();
+	    while (iter.hasNext())
+	      {
+		// Don't iterate the values, since we want to count
+		// doubled values (aliases)
+		Map.Entry entry = (Map.Entry) iter.next();
+		if (((TimeZone) entry.getValue()).getRawOffset() == rawOffset)
+		  count++;
+	      }
+
+	    String[] ids = new String[count];
+	    count = 0;
+	    iter = h.entrySet().iterator();
+	    while (iter.hasNext())
+	      {
+		Map.Entry entry = (Map.Entry) iter.next();
+		if (((TimeZone) entry.getValue()).getRawOffset() == rawOffset)
+		  ids[count++] = (String) entry.getKey();
+	      }
+	    return ids;
+	  }
+      }
+
+    String[] s = getAvailableIDs();
     int count = 0;
-    Iterator iter = timezones().entrySet().iterator();
-    while (iter.hasNext())
+    for (int i = 0; i < s.length; i++)
       {
-	// Don't iterate the values, since we want to count 
-	// doubled values (aliases)
-	Map.Entry entry = (Map.Entry) iter.next();
-	if (((TimeZone) entry.getValue()).getRawOffset() == rawOffset)
+	TimeZone t = getTimeZoneInternal(s[i]);
+	if (t == null || t.getRawOffset() != rawOffset)
+	  s[i] = null;
+	else
 	  count++;
       }
-
     String[] ids = new String[count];
     count = 0;
-    iter = timezones().entrySet().iterator();
-    while (iter.hasNext())
-      {
-	Map.Entry entry = (Map.Entry) iter.next();
-	if (((TimeZone) entry.getValue()).getRawOffset() == rawOffset)
-	  ids[count++] = (String) entry.getKey();
-      }
+    for (int i = 0; i < s.length; i++)
+    if (s[i] != null)
+      ids[count++] = s[i];
+
     return ids;
   }
 
+  private static int getAvailableIDs(File d, String prefix, ArrayList list)
+    {
+      String[] files = d.list();
+      int count = files.length;
+      boolean top = prefix.length() == 0;
+      list.add (files);
+      for (int i = 0; i < files.length; i++)
+	{
+	  if (top
+	      && (files[i].equals("posix")
+		  || files[i].equals("right")
+		  || files[i].endsWith(".tab")
+		  || aliases0.get(files[i]) != null))
+	    {
+	      files[i] = null;
+	      count--;
+	      continue;
+	    }
+
+	  File f = new File(d, files[i]);
+	  if (f.isDirectory())
+	    {
+	      count += getAvailableIDs(f, prefix + files[i]
+				       + File.separatorChar, list) - 1;
+	      files[i] = null;
+	    }
+	  else
+	    files[i] = prefix + files[i];
+	}
+      return count;
+    }
+
   /**
    * Gets all available IDs.
    * @return An array of all supported IDs.
    */
   public static String[] getAvailableIDs()
   {
-    return (String[])
-      timezones().keySet().toArray(new String[timezones().size()]);
+    synchronized (TimeZone.class)
+      {
+	HashMap h = timezones();
+	if (zoneinfo_dir == null)
+	  return (String[]) h.keySet().toArray(new String[h.size()]);
+
+	if (availableIDs != null)
+	  {
+	    String[] ids = new String[availableIDs.length];
+	    for (int i = 0; i < availableIDs.length; i++)
+	      ids[i] = availableIDs[i];
+	    return ids;
+	  }
+
+	File d = new File(zoneinfo_dir);
+	ArrayList list = new ArrayList(30);
+	int count = getAvailableIDs(d, "", list) + aliases0.size();
+	availableIDs = new String[count];
+	String[] ids = new String[count];
+
+	count = 0;
+	for (int i = 0; i < list.size(); i++)
+	  {
+	    String[] s = (String[]) list.get(i);
+	    for (int j = 0; j < s.length; j++)
+	      if (s[j] != null)
+		{
+		  availableIDs[count] = s[j];
+		  ids[count++] = s[j];
+		}
+	  }
+
+	Iterator iter = aliases0.entrySet().iterator();
+	while (iter.hasNext())
+	  {
+	    Map.Entry entry = (Map.Entry) iter.next();
+	    availableIDs[count] = (String) entry.getKey();
+	    ids[count++] = (String) entry.getKey();
+	  }
+
+	return ids;
+      }
   }
 
   /**