1 /*
   2  * Copyright (c) 2000, 2004, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 import java.util.ArrayList;
  27 import java.util.List;
  28 
  29 /**
  30  * Timezone represents all information of a single point of time to
  31  * generate its time zone database.
  32  *
  33  * @since 1.4
  34  */
  35 class Timezone {
  36     /**
  37      * zone name of this time zone
  38      */
  39     private String name;
  40 
  41     /**
  42      * transition time values in UTC (millisecond)
  43      */
  44     private List<Long> transitions;
  45 
  46     /**
  47      * All offset values in millisecond
  48      * @see sun.util.calendar.ZoneInfo
  49      */
  50     private List<Integer> offsets;
  51 
  52     /**
  53      * Indices of GMT offset values (both raw and raw+saving)
  54      * at transitions
  55      */
  56     private List<Integer> gmtOffsets;
  57 
  58     /**
  59      * Indices of regular or "direct" saving time values
  60      * at transitions
  61      */
  62     private List<Integer> dstOffsets;
  63 
  64     /**
  65      * Zone records of this time zone
  66      */
  67     private List<ZoneRec> usedZoneRecs;
  68 
  69     /**
  70      * Rule records referred to by this time zone
  71      */
  72     private List<RuleRec> usedRuleRecs;
  73 
  74     /**
  75      * Type of DST rules in this time zone
  76      */
  77     private int dstType;
  78     static final int UNDEF_DST = 0;     // DST type not set yet
  79     static final int NO_DST = 1;        // never observed DST
  80     static final int LAST_DST = 2;      // last rule ends in DST (all year round DST-only)
  81     static final int X_DST = 3;         // used to observe DST
  82     static final int DST = 4;           // observing DST regularly
  83 
  84     /**
  85      * Raw GMT offset of this time zone in the last rule
  86      */
  87     private int rawOffset;
  88 
  89     /**
  90      * The CRC32 value of the transitions data
  91      */
  92     private int crc32;
  93 
  94     /**
  95      * The last ZoneRec
  96      */
  97     private ZoneRec lastZoneRec;
  98 
  99     /**
 100      * The last DST rules. lastRules[0] is the DST start
 101      * rule. lastRules[1] is the DST end rules.
 102      */
 103     private List<RuleRec> lastRules;
 104 
 105     /**
 106      * The amount of DST saving value (millisecond) in the last DST
 107      * rule.
 108      */
 109     private int lastSaving;
 110 
 111     /**
 112      * true if the raw offset will change in the future time.
 113      */
 114     private boolean willRawOffsetChange = false;
 115 
 116 
 117     /**
 118      * Constracts a Timezone object with the given zone name.
 119      * @param name the zone name
 120      */
 121     Timezone(String name) {
 122         this.name = name;
 123     }
 124 
 125     /**
 126      * @return the number of transitions
 127      */
 128     int getNTransitions() {
 129         if (transitions == null) {
 130             return 0;
 131         }
 132         return transitions.size();
 133     }
 134 
 135     /**
 136      * @return the zone name
 137      */
 138     String getName() {
 139         return name;
 140     }
 141 
 142     /**
 143      * Returns the list of all rule records that have been referred to
 144      * by this time zone.
 145      * @return the rule records list
 146      */
 147     List<RuleRec> getRules() {
 148         return usedRuleRecs;
 149     }
 150 
 151     /**
 152      * Returns the list of all zone records that have been referred to
 153      * by this time zone.
 154      * @return the zone records list
 155      */
 156     List<ZoneRec> getZones() {
 157         return usedZoneRecs;
 158     }
 159 
 160     /**
 161      * @return the transition table (list)
 162      */
 163     List<Long> getTransitions() {
 164         return transitions;
 165     }
 166 
 167     /**
 168      * @return the offsets list
 169      */
 170     List<Integer> getOffsets() {
 171         return offsets;
 172     }
 173 
 174     /**
 175      * @return the DST saving offsets list
 176      */
 177     List<Integer> getDstOffsets() {
 178         return dstOffsets;
 179     }
 180 
 181     /**
 182      * @return the GMT offsets list
 183      */
 184     List<Integer> getGmtOffsets() {
 185         return gmtOffsets;
 186     }
 187 
 188     /**
 189      * @return the checksum (crc32) value of the trasition table
 190      */
 191     int getCRC32() {
 192         return crc32;
 193     }
 194 
 195     /**
 196      * @return true if the GMT offset of this time zone would change
 197      * after the time zone database has been generated, false, otherwise.
 198      */
 199     boolean willGMTOffsetChange() {
 200         return willRawOffsetChange;
 201     }
 202 
 203     /**
 204      * @return the last known GMT offset value in milliseconds
 205      */
 206     int getRawOffset() {
 207         return rawOffset;
 208     }
 209 
 210     /**
 211      * Sets time zone's GMT offset to <code>offset</code>.
 212      * @param offset the GMT offset value in milliseconds
 213      */
 214     void setRawOffset(int offset) {
 215         rawOffset = offset;
 216     }
 217 
 218     /**
 219      * Sets time zone's GMT offset value to <code>offset</code>. If
 220      * <code>startTime</code> is future time, then the {@link
 221      * #willRawOffsetChange} value is set to true.
 222      * @param offset the GMT offset value in milliseconds
 223      * @param startTime the UTC time at which the GMT offset is in effective
 224      */
 225     void setRawOffset(int offset, long startTime) {
 226         // if this rawOffset is for the future time, let the run-time
 227         // look for the current GMT offset.
 228         if (startTime > Time.getCurrentTime()) {
 229             willRawOffsetChange = true;
 230         }
 231         setRawOffset(offset);
 232     }
 233 
 234     /**
 235      * Adds the specified transition information to the end of the transition table.
 236      * @param time the UTC time at which this transition happens
 237      * @param offset the total amount of the offset from GMT in milliseconds
 238      * @param dstOffset the amount of time in milliseconds saved at this transition
 239      */
 240     void addTransition(long time, int offset, int dstOffset) {
 241         if (transitions == null) {
 242             transitions = new ArrayList<Long>();
 243             offsets = new ArrayList<Integer>();
 244             dstOffsets = new ArrayList<Integer>();
 245         }
 246         transitions.add(time);
 247         offsets.add(offset);
 248         dstOffsets.add(dstOffset);
 249     }
 250 
 251     /**
 252      * Sets the type of historical daylight saving time
 253      * observation. For example, China used to observed daylight
 254      * saving time, but it no longer does. Then, X_DST is set to the
 255      * China time zone.
 256      * @param type the type of daylight saving time
 257      */
 258     void setDSTType(int type) {
 259         dstType = type;
 260     }
 261 
 262     /**
 263      * @return the type of historical daylight saving time
 264      * observation.
 265      */
 266     int getDSTType() {
 267         return dstType;
 268     }
 269 
 270     /**
 271      * Adds the specified zone record to the zone records list.
 272      * @param rec the zone record
 273      */
 274     void addUsedRec(ZoneRec rec) {
 275         if (usedZoneRecs == null) {
 276             usedZoneRecs = new ArrayList<ZoneRec>();
 277         }
 278         usedZoneRecs.add(rec);
 279     }
 280 
 281     /**
 282      * Adds the specified rule record to the rule records list.
 283      * @param rec the rule record
 284      */
 285     void addUsedRec(RuleRec rec) {
 286         if (usedRuleRecs == null) {
 287             usedRuleRecs = new ArrayList<RuleRec>();
 288         }
 289         // if the last used rec is the same as the given rec, avoid
 290         // putting the same rule.
 291         int n = usedRuleRecs.size();
 292         for (int i = 0; i < n; i++) {
 293             if (usedRuleRecs.get(i).equals(rec)) {
 294                 return;
 295             }
 296         }
 297         usedRuleRecs.add(rec);
 298     }
 299 
 300     /**
 301      * Sets the last zone record for this time zone.
 302      * @param the last zone record
 303      */
 304     void setLastZoneRec(ZoneRec zrec) {
 305         lastZoneRec = zrec;
 306     }
 307 
 308     /**
 309      * @return the last zone record for this time zone.
 310      */
 311     ZoneRec getLastZoneRec() {
 312         return lastZoneRec;
 313     }
 314 
 315     /**
 316      * Sets the last rule records for this time zone. Those are used
 317      * for generating SimpleTimeZone parameters.
 318      * @param rules the last rule records
 319      */
 320     void setLastRules(List<RuleRec> rules) {
 321         int n = rules.size();
 322         if (n > 0) {
 323             lastRules = rules;
 324             RuleRec rec = rules.get(0);
 325             int offset = rec.getSave();
 326             if (offset > 0) {
 327                 setLastDSTSaving(offset);
 328             } else {
 329                 System.err.println("\t    No DST starting rule in the last rules.");
 330             }
 331         }
 332     }
 333 
 334     /**
 335      * @return the last rule records for this time zone.
 336      */
 337     List<RuleRec> getLastRules() {
 338         return lastRules;
 339     }
 340 
 341     /**
 342      * Sets the last daylight saving amount.
 343      * @param the daylight saving amount
 344      */
 345     void setLastDSTSaving(int offset) {
 346         lastSaving = offset;
 347     }
 348 
 349     /**
 350      * @return the last daylight saving amount.
 351      */
 352     int getLastDSTSaving() {
 353         return lastSaving;
 354     }
 355 
 356     /**
 357      * Calculates the CRC32 value from the transition table and sets
 358      * the value to <code>crc32</code>.
 359      */
 360     void checksum() {
 361         if (transitions == null) {
 362             crc32 = 0;
 363             return;
 364         }
 365         Checksum sum = new Checksum();
 366         for (int i = 0; i < transitions.size(); i++) {
 367             int offset = offsets.get(i);
 368             // adjust back to make the transition in local time
 369             sum.update(transitions.get(i) + offset);
 370             sum.update(offset);
 371             sum.update(dstOffsets.get(i));
 372         }
 373         crc32 = (int)sum.getValue();
 374     }
 375 
 376     /**
 377      * Removes unnecessary transitions for Java time zone support.
 378      */
 379     void optimize() {
 380         // if there is only one offset, delete all transitions. This
 381         // could happen if only time zone abbreviations changed.
 382         if (gmtOffsets.size() == 1) {
 383             transitions = null;
 384             usedRuleRecs =  null;
 385             setDSTType(NO_DST);
 386             return;
 387         }
 388         for (int i = 0; i < (transitions.size() - 2); i++) { // don't remove the last one
 389             if (transitions.get(i) == transitions.get(i+1)) {
 390                 transitions.remove(i);
 391                 offsets.remove(i);
 392                 dstOffsets.remove(i);
 393                 i--;
 394             }
 395         }
 396 
 397         for (int i = 0; i < (transitions.size() - 2); i++) { // don't remove the last one
 398             if (offsets.get(i) == offsets.get(i+1)
 399                 && dstOffsets.get(i) == dstOffsets.get(i+1)) {
 400                 transitions.remove(i+1);
 401                 offsets.remove(i+1);
 402                 dstOffsets.remove(i+1);
 403                 i--;
 404             }
 405         }
 406     }
 407 
 408     /**
 409      * Stores the specified offset value from GMT in the GMT offsets
 410      * table and returns its index. The offset value includes the base
 411      * GMT offset and any additional daylight saving if applicable. If
 412      * the same value as the specified offset is already in the table,
 413      * its index is returned.
 414      * @param offset the offset value in milliseconds
 415      * @return the index to the offset value in the GMT offsets table.
 416      */
 417     int getOffsetIndex(int offset) {
 418         return getOffsetIndex(offset, 0);
 419     }
 420 
 421     /**
 422      * Stores the specified daylight saving value in the GMT offsets
 423      * table and returns its index. If the same value as the specified
 424      * offset is already in the table, its index is returned. If 0 is
 425      * specified, it's not stored in the table and -1 is returned.
 426      * @param offset the offset value in milliseconds
 427      * @return the index to the specified offset value in the GMT
 428      * offsets table, or -1 if 0 is specified.
 429      */
 430     int getDstOffsetIndex(int offset) {
 431         if (offset == 0) {
 432             return -1;
 433         }
 434         return getOffsetIndex(offset, 1);
 435     }
 436 
 437     private int getOffsetIndex(int offset, int index) {
 438         if (gmtOffsets == null) {
 439             gmtOffsets = new ArrayList<Integer>();
 440         }
 441         for (int i = index; i < gmtOffsets.size(); i++) {
 442             if (offset == gmtOffsets.get(i)) {
 443                 return i;
 444             }
 445         }
 446         if (gmtOffsets.size() < index) {
 447             gmtOffsets.add(0);
 448         }
 449         gmtOffsets.add(offset);
 450         return gmtOffsets.size() - 1;
 451     }
 452 }