mcs/class/System.Core/System/TimeZoneInfo.cs

   1 /*
   2  * System.TimeZoneInfo
   3  *
   4  * Author(s)
   5  *      Stephane Delcroix <stephane@delcroix.org>
   6  *
   7  * Copyright 2011 Xamarin Inc.
   8  *
   9  * Permission is hereby granted, free of charge, to any person obtaining
  10  * a copy of this software and associated documentation files (the
  11  * "Software"), to deal in the Software without restriction, including
  12  * without limitation the rights to use, copy, modify, merge, publish,
  13  * distribute, sublicense, and/or sell copies of the Software, and to
  14  * permit persons to whom the Software is furnished to do so, subject to
  15  * the following conditions:
  16  *
  17  * The above copyright notice and this permission notice shall be
  18  * included in all copies or substantial portions of the Software.
  19  *
  20  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  21  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  22  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  23  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  24  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  25  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  26  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  27  */
  28
  29 using System;
  30 using System.Runtime.CompilerServices;
  31
  32 #if !INSIDE_CORLIB && (NET_4_0 || MOONLIGHT || MOBILE)
  33
  34 [assembly:TypeForwardedTo (typeof(TimeZoneInfo))]
  35
  36 #elif (INSIDE_CORLIB && (NET_4_0 || MOONLIGHT || MOBILE)) || (!INSIDE_CORLIB && (NET_3_5 && !NET_4_0 && !MOBILE))
  37
  38 using System.Collections.Generic;
  39 using System.Collections.ObjectModel;
  40 using System.Runtime.Serialization;
  41 using System.Text;
  42
  43 #if LIBC || MONODROID
  44 using System.IO;
  45 using Mono;
  46 #endif
  47
  48 using Microsoft.Win32;
  49
  50 namespace System
  51 {
  52 #if NET_4_0
  53         [TypeForwardedFrom (Consts.AssemblySystemCore_3_5)]
  54 #elif MOONLIGHT || MOBILE
  55         [TypeForwardedFrom (Consts.AssemblySystem_Core)]
  56 #endif
  57         [SerializableAttribute]
  58         public sealed partial class TimeZoneInfo : IEquatable<TimeZoneInfo>, ISerializable, IDeserializationCallback
  59         {
  60                 TimeSpan baseUtcOffset;
  61                 public TimeSpan BaseUtcOffset {
  62                         get { return baseUtcOffset; }
  63                 }
  64
  65                 string daylightDisplayName;
  66                 public string DaylightName {
  67                         get {
  68                                 if (disableDaylightSavingTime)
  69                                         return String.Empty;
  70                                 return daylightDisplayName;
  71                         }
  72                 }
  73
  74                 string displayName;
  75                 public string DisplayName {
  76                         get { return displayName; }
  77                 }
  78
  79                 string id;
  80                 public string Id {
  81                         get { return id; }
  82                 }
  83
  84                 static TimeZoneInfo local;
  85                 public static TimeZoneInfo Local {
  86                         get {
  87                                 if (local == null) {
  88 #if MONODROID
  89                                         local = ZoneInfoDB.Default;
  90 #elif MONOTOUCH
  91                                         using (Stream stream = GetMonoTouchDefault ()) {
  92                                                 return BuildFromStream ("Local", stream);
  93                                         }
  94 #elif LIBC
  95                                         try {
  96                                                 local = FindSystemTimeZoneByFileName ("Local", "/etc/localtime");
  97                                         } catch {
  98                                                 try {
  99                                                         local = FindSystemTimeZoneByFileName ("Local", Path.Combine (TimeZoneDirectory, "localtime"));
 100                                                 } catch {
 101                                                         throw new TimeZoneNotFoundException ();
 102                                                 }
 103                                         }
 104 #else
 105                                         throw new TimeZoneNotFoundException ();
 106 #endif
 107                                 }
 108                                 return local;
 109                         }
 110                 }
 111
 112                 string standardDisplayName;
 113                 public string StandardName {
 114                         get { return standardDisplayName; }
 115                 }
 116
 117                 bool disableDaylightSavingTime;
 118                 public bool SupportsDaylightSavingTime {
 119                         get  { return !disableDaylightSavingTime; }
 120                 }
 121
 122                 static TimeZoneInfo utc;
 123                 public static TimeZoneInfo Utc {
 124                         get {
 125                                 if (utc == null)
 126                                         utc = CreateCustomTimeZone ("UTC", new TimeSpan (0), "UTC", "UTC");
 127                                 return utc;
 128                         }
 129                 }
 130 #if LIBC
 131                 static string timeZoneDirectory = null;
 132                 static string TimeZoneDirectory {
 133                         get {
 134                                 if (timeZoneDirectory == null)
 135                                         timeZoneDirectory = "/usr/share/zoneinfo";
 136                                 return timeZoneDirectory;
 137                         }
 138                         set {
 139                                 ClearCachedData ();
 140                                 timeZoneDirectory = value;
 141                         }
 142                 }
 143 #endif
 144                 private AdjustmentRule [] adjustmentRules;
 145
 146 #if !NET_2_1
 147                 static RegistryKey timeZoneKey = null;
 148                 static bool timeZoneKeySet = false;
 149                 static RegistryKey TimeZoneKey {
 150                         get {
 151                                 if (!timeZoneKeySet) {
 152                                         int p = (int) Environment.OSVersion.Platform;
 153                                         /* Only use the registry on non-Unix platforms. */
 154                                         if ((p != 4) && (p != 6) && (p != 128))
 155                                                 timeZoneKey = Registry.LocalMachine.OpenSubKey (
 156                                                         "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones",
 157                                                         false);
 158                                         timeZoneKeySet = true;
 159                                 }
 160                                 return timeZoneKey;
 161                         }
 162                 }
 163 #endif
 164
 165                 public static void ClearCachedData ()
 166                 {
 167                         local = null;
 168                         utc = null;
 169                         systemTimeZones = null;
 170                 }
 171
 172                 public static DateTime ConvertTime (DateTime dateTime, TimeZoneInfo destinationTimeZone)
 173                 {
 174                         return ConvertTime (dateTime, TimeZoneInfo.Local, destinationTimeZone);
 175                 }
 176
 177                 public static DateTime ConvertTime (DateTime dateTime, TimeZoneInfo sourceTimeZone, TimeZoneInfo destinationTimeZone)
 178                 {
 179                         if (dateTime.Kind == DateTimeKind.Local && sourceTimeZone != TimeZoneInfo.Local)
 180                                 throw new ArgumentException ("Kind propery of dateTime is Local but the sourceTimeZone does not equal TimeZoneInfo.Local");
 181
 182                         if (dateTime.Kind == DateTimeKind.Utc && sourceTimeZone != TimeZoneInfo.Utc)
 183                                 throw new ArgumentException ("Kind propery of dateTime is Utc but the sourceTimeZone does not equal TimeZoneInfo.Utc");
 184
 185                         if (sourceTimeZone.IsInvalidTime (dateTime))
 186                                 throw new ArgumentException ("dateTime parameter is an invalid time");
 187
 188                         if (sourceTimeZone == null)
 189                                 throw new ArgumentNullException ("sourceTimeZone");
 190
 191                         if (destinationTimeZone == null)
 192                                 throw new ArgumentNullException ("destinationTimeZone");
 193
 194                         if (dateTime.Kind == DateTimeKind.Local && sourceTimeZone == TimeZoneInfo.Local && destinationTimeZone == TimeZoneInfo.Local)
 195                                 return dateTime;
 196
 197                         DateTime utc = ConvertTimeToUtc (dateTime);
 198
 199                         if (destinationTimeZone == TimeZoneInfo.Utc)
 200                                 return utc;
 201
 202                         return ConvertTimeFromUtc (utc, destinationTimeZone);
 203
 204                 }
 205
 206                 public static DateTimeOffset ConvertTime (DateTimeOffset dateTimeOffset, TimeZoneInfo destinationTimeZone)
 207                 {
 208                         throw new NotImplementedException ();
 209                 }
 210
 211                 public static DateTime ConvertTimeBySystemTimeZoneId (DateTime dateTime, string destinationTimeZoneId)
 212                 {
 213                         return ConvertTime (dateTime, FindSystemTimeZoneById (destinationTimeZoneId));
 214                 }
 215
 216                 public static DateTime ConvertTimeBySystemTimeZoneId (DateTime dateTime, string sourceTimeZoneId, string destinationTimeZoneId)
 217                 {
 218                         return ConvertTime (dateTime, FindSystemTimeZoneById (sourceTimeZoneId), FindSystemTimeZoneById (destinationTimeZoneId));
 219                 }
 220
 221                 public static DateTimeOffset ConvertTimeBySystemTimeZoneId (DateTimeOffset dateTimeOffset, string destinationTimeZoneId)
 222                 {
 223                         return ConvertTime (dateTimeOffset, FindSystemTimeZoneById (destinationTimeZoneId));
 224                 }
 225
 226                 private DateTime ConvertTimeFromUtc (DateTime dateTime)
 227                 {
 228                         if (dateTime.Kind == DateTimeKind.Local)
 229                                 throw new ArgumentException ("Kind property of dateTime is Local");
 230
 231                         if (this == TimeZoneInfo.Utc)
 232                                 return DateTime.SpecifyKind (dateTime, DateTimeKind.Utc);
 233
 234                         //FIXME: do not rely on DateTime implementation !
 235                         if (this == TimeZoneInfo.Local)
 236                                 return DateTime.SpecifyKind (dateTime.ToLocalTime (), DateTimeKind.Unspecified);
 237
 238                         AdjustmentRule rule = GetApplicableRule (dateTime);
 239
 240                         if (rule != null && IsDaylightSavingTime (DateTime.SpecifyKind (dateTime, DateTimeKind.Utc)))
 241                                 return DateTime.SpecifyKind (dateTime + BaseUtcOffset + rule.DaylightDelta , DateTimeKind.Unspecified);
 242                         else
 243                                 return DateTime.SpecifyKind (dateTime + BaseUtcOffset, DateTimeKind.Unspecified);
 244                 }
 245
 246                 public static DateTime ConvertTimeFromUtc (DateTime dateTime, TimeZoneInfo destinationTimeZone)
 247                 {
 248                         if (destinationTimeZone == null)
 249                                 throw new ArgumentNullException ("destinationTimeZone");
 250
 251                         return destinationTimeZone.ConvertTimeFromUtc (dateTime);
 252                 }
 253
 254                 public static DateTime ConvertTimeToUtc (DateTime dateTime)
 255                 {
 256                         if (dateTime.Kind == DateTimeKind.Utc)
 257                                 return dateTime;
 258
 259                         //FIXME: do not rely on DateTime implementation !
 260                         return DateTime.SpecifyKind (dateTime.ToUniversalTime (), DateTimeKind.Utc);
 261                 }
 262
 263                 public static DateTime ConvertTimeToUtc (DateTime dateTime, TimeZoneInfo sourceTimeZone)
 264                 {
 265                         if (sourceTimeZone == null)
 266                                 throw new ArgumentNullException ("sourceTimeZone");
 267
 268                         if (dateTime.Kind == DateTimeKind.Utc && sourceTimeZone != TimeZoneInfo.Utc)
 269                                 throw new ArgumentException ("Kind propery of dateTime is Utc but the sourceTimeZone does not equal TimeZoneInfo.Utc");
 270
 271                         if (dateTime.Kind == DateTimeKind.Local && sourceTimeZone != TimeZoneInfo.Local)
 272                                 throw new ArgumentException ("Kind propery of dateTime is Local but the sourceTimeZone does not equal TimeZoneInfo.Local");
 273
 274                         if (sourceTimeZone.IsInvalidTime (dateTime))
 275                                 throw new ArgumentException ("dateTime parameter is an invalid time");
 276
 277                         if (dateTime.Kind == DateTimeKind.Utc && sourceTimeZone == TimeZoneInfo.Utc)
 278                                 return dateTime;
 279
 280                         if (dateTime.Kind == DateTimeKind.Utc)
 281                                 return dateTime;
 282
 283                         if (dateTime.Kind == DateTimeKind.Local)
 284                                 return ConvertTimeToUtc (dateTime);
 285
 286                         if (sourceTimeZone.IsAmbiguousTime (dateTime) || !sourceTimeZone.IsDaylightSavingTime (dateTime))
 287                                 return DateTime.SpecifyKind (dateTime - sourceTimeZone.BaseUtcOffset, DateTimeKind.Utc);
 288                         else {
 289                                 AdjustmentRule rule = sourceTimeZone.GetApplicableRule (dateTime);
 290                                 if (rule != null)
 291                                         return DateTime.SpecifyKind (dateTime - sourceTimeZone.BaseUtcOffset - rule.DaylightDelta, DateTimeKind.Utc);
 292                                 else
 293                                         return DateTime.SpecifyKind (dateTime - sourceTimeZone.BaseUtcOffset, DateTimeKind.Utc);
 294                         }
 295                 }
 296
 297                 public static TimeZoneInfo CreateCustomTimeZone (string id, TimeSpan baseUtcOffset, string displayName, string standardDisplayName)
 298                 {
 299                         return CreateCustomTimeZone (id, baseUtcOffset, displayName, standardDisplayName, null, null, true);
 300                 }
 301
 302                 public static TimeZoneInfo CreateCustomTimeZone (string id, TimeSpan baseUtcOffset, string displayName, string standardDisplayName, string daylightDisplayName, TimeZoneInfo.AdjustmentRule [] adjustmentRules)
 303                 {
 304                         return CreateCustomTimeZone (id, baseUtcOffset, displayName, standardDisplayName, daylightDisplayName, adjustmentRules, false);
 305                 }
 306
 307                 public static TimeZoneInfo CreateCustomTimeZone ( string id, TimeSpan baseUtcOffset, string displayName, string standardDisplayName, string daylightDisplayName, TimeZoneInfo.AdjustmentRule [] adjustmentRules, bool disableDaylightSavingTime)
 308                 {
 309                         return new TimeZoneInfo (id, baseUtcOffset, displayName, standardDisplayName, daylightDisplayName, adjustmentRules, disableDaylightSavingTime);
 310                 }
 311
 312                 public bool Equals (TimeZoneInfo other)
 313                 {
 314                         if (other == null)
 315                                 return false;
 316
 317                         return other.Id == this.Id && HasSameRules (other);
 318                 }
 319
 320                 public static TimeZoneInfo FindSystemTimeZoneById (string id)
 321                 {
 322                         //FIXME: this method should check for cached values in systemTimeZones
 323                         if (id == null)
 324                                 throw new ArgumentNullException ("id");
 325 #if !NET_2_1
 326                         if (TimeZoneKey != null)
 327                         {
 328                                 RegistryKey key = TimeZoneKey.OpenSubKey (id, false);
 329                                 if (key == null)
 330                                         throw new TimeZoneNotFoundException ();
 331                                 return FromRegistryKey(id, key);
 332                         }
 333 #endif
 334 #if MONODROID
 335                         return ZoneInfoDB.GetTimeZone (id);
 336 #else
 337                         // Local requires special logic that already exists in the Local property (bug #326)
 338                         if (id == "Local")
 339                                 return Local;
 340 #if MONOTOUCH
 341                         using (Stream stream = GetMonoTouchData (id)) {
 342                                 return BuildFromStream (id, stream);
 343                         }
 344 #elif LIBC
 345                         string filepath = Path.Combine (TimeZoneDirectory, id);
 346                         return FindSystemTimeZoneByFileName (id, filepath);
 347 #endif
 348                         throw new NotImplementedException ();
 349 #endif
 350                 }
 351
 352 #if LIBC
 353                 private static TimeZoneInfo FindSystemTimeZoneByFileName (string id, string filepath)
 354                 {
 355                         if (!File.Exists (filepath))
 356                                 throw new TimeZoneNotFoundException ();
 357
 358                         using (FileStream stream = File.OpenRead (filepath)) {
 359                                 return BuildFromStream (id, stream);
 360                         }
 361                 }
 362 #endif
 363 #if LIBC || MONOTOUCH
 364                 const int BUFFER_SIZE = 16384; //Big enough for any tz file (on Oct 2008, all tz files are under 10k)
 365
 366                 private static TimeZoneInfo BuildFromStream (string id, Stream stream)
 367                 {
 368                         byte [] buffer = new byte [BUFFER_SIZE];
 369                         int length = stream.Read (buffer, 0, BUFFER_SIZE);
 370
 371                         if (!ValidTZFile (buffer, length))
 372                                 throw new InvalidTimeZoneException ("TZ file too big for the buffer");
 373
 374                         try {
 375                                 return ParseTZBuffer (id, buffer, length);
 376                         } catch (Exception e) {
 377                                 throw new InvalidTimeZoneException (e.Message);
 378                         }
 379                 }
 380 #endif
 381
 382 #if !NET_2_1
 383                 private static TimeZoneInfo FromRegistryKey (string id, RegistryKey key)
 384                 {
 385                         byte [] reg_tzi = (byte []) key.GetValue ("TZI");
 386
 387                         if (reg_tzi == null)
 388                                 throw new InvalidTimeZoneException ();
 389
 390                         int bias = BitConverter.ToInt32 (reg_tzi, 0);
 391                         TimeSpan baseUtcOffset = new TimeSpan (0, -bias, 0);
 392
 393                         string display_name = (string) key.GetValue ("Display");
 394                         string standard_name = (string) key.GetValue ("Std");
 395                         string daylight_name = (string) key.GetValue ("Dlt");
 396
 397                         List<AdjustmentRule> adjustmentRules = new List<AdjustmentRule> ();
 398
 399                         RegistryKey dst_key = key.OpenSubKey ("Dynamic DST", false);
 400                         if (dst_key != null) {
 401                                 int first_year = (int) dst_key.GetValue ("FirstEntry");
 402                                 int last_year = (int) dst_key.GetValue ("LastEntry");
 403                                 int year;
 404
 405                                 for (year=first_year; year<=last_year; year++) {
 406                                         byte [] dst_tzi = (byte []) dst_key.GetValue (year.ToString ());
 407                                         if (dst_tzi != null) {
 408                                                 int start_year = year == first_year ? 1 : year;
 409                                                 int end_year = year == last_year ? 9999 : year;
 410                                                 ParseRegTzi(adjustmentRules, start_year, end_year, dst_tzi);
 411                                         }
 412                                 }
 413                         }
 414                         else
 415                                 ParseRegTzi(adjustmentRules, 1, 9999, reg_tzi);
 416
 417                         return CreateCustomTimeZone (id, baseUtcOffset, display_name, standard_name, daylight_name, ValidateRules (adjustmentRules).ToArray ());
 418                 }
 419
 420                 private static void ParseRegTzi (List<AdjustmentRule> adjustmentRules, int start_year, int end_year, byte [] buffer)
 421                 {
 422                         //int standard_bias = BitConverter.ToInt32 (buffer, 4); /* not sure how to handle this */
 423                         int daylight_bias = BitConverter.ToInt32 (buffer, 8);
 424
 425                         int standard_year = BitConverter.ToInt16 (buffer, 12);
 426                         int standard_month = BitConverter.ToInt16 (buffer, 14);
 427                         int standard_dayofweek = BitConverter.ToInt16 (buffer, 16);
 428                         int standard_day = BitConverter.ToInt16 (buffer, 18);
 429                         int standard_hour = BitConverter.ToInt16 (buffer, 20);
 430                         int standard_minute = BitConverter.ToInt16 (buffer, 22);
 431                         int standard_second = BitConverter.ToInt16 (buffer, 24);
 432                         int standard_millisecond = BitConverter.ToInt16 (buffer, 26);
 433
 434                         int daylight_year = BitConverter.ToInt16 (buffer, 28);
 435                         int daylight_month = BitConverter.ToInt16 (buffer, 30);
 436                         int daylight_dayofweek = BitConverter.ToInt16 (buffer, 32);
 437                         int daylight_day = BitConverter.ToInt16 (buffer, 34);
 438                         int daylight_hour = BitConverter.ToInt16 (buffer, 36);
 439                         int daylight_minute = BitConverter.ToInt16 (buffer, 38);
 440                         int daylight_second = BitConverter.ToInt16 (buffer, 40);
 441                         int daylight_millisecond = BitConverter.ToInt16 (buffer, 42);
 442
 443                         if (standard_month == 0 || daylight_month == 0)
 444                                 return;
 445
 446                         DateTime start_date;
 447                         DateTime start_timeofday = new DateTime (1, 1, 1, daylight_hour, daylight_minute, daylight_second, daylight_millisecond);
 448                         TransitionTime start_transition_time;
 449
 450                         if (daylight_year == 0) {
 451                                 start_date = new DateTime (start_year, 1, 1);
 452                                 start_transition_time = TransitionTime.CreateFloatingDateRule (
 453                                         start_timeofday, daylight_month, daylight_day,
 454                                         (DayOfWeek) daylight_dayofweek);
 455                         }
 456                         else {
 457                                 start_date = new DateTime (daylight_year, daylight_month, daylight_day,
 458                                         daylight_hour, daylight_minute, daylight_second, daylight_millisecond);
 459                                 start_transition_time = TransitionTime.CreateFixedDateRule (
 460                                         start_timeofday, daylight_month, daylight_day);
 461                         }
 462
 463                         DateTime end_date;
 464                         DateTime end_timeofday = new DateTime (1, 1, 1, standard_hour, standard_minute, standard_second, standard_millisecond);
 465                         TransitionTime end_transition_time;
 466
 467                         if (standard_year == 0) {
 468                                 end_date = new DateTime (end_year, 12, 31);
 469                                 end_transition_time = TransitionTime.CreateFloatingDateRule (
 470                                         end_timeofday, standard_month, standard_day,
 471                                         (DayOfWeek) standard_dayofweek);
 472                         }
 473                         else {
 474                                 end_date = new DateTime (standard_year, standard_month, standard_day,
 475                                         standard_hour, standard_minute, standard_second, standard_millisecond);
 476                                 end_transition_time = TransitionTime.CreateFixedDateRule (
 477                                         end_timeofday, standard_month, standard_day);
 478                         }
 479
 480                         TimeSpan daylight_delta = new TimeSpan(0, -daylight_bias, 0);
 481
 482                         adjustmentRules.Add (AdjustmentRule.CreateAdjustmentRule (
 483                                 start_date, end_date, daylight_delta,
 484                                 start_transition_time, end_transition_time));
 485                 }
 486 #endif
 487
 488                 public static TimeZoneInfo FromSerializedString (string source)
 489                 {
 490                         throw new NotImplementedException ();
 491                 }
 492
 493                 public AdjustmentRule [] GetAdjustmentRules ()
 494                 {
 495                         if (disableDaylightSavingTime)
 496                                 return new AdjustmentRule [0];
 497                         else
 498                                 return (AdjustmentRule []) adjustmentRules.Clone ();
 499                 }
 500
 501                 public TimeSpan [] GetAmbiguousTimeOffsets (DateTime dateTime)
 502                 {
 503                         if (!IsAmbiguousTime (dateTime))
 504                                 throw new ArgumentException ("dateTime is not an ambiguous time");
 505
 506                         AdjustmentRule rule = GetApplicableRule (dateTime);
 507                         if (rule != null)
 508                                 return new TimeSpan[] {baseUtcOffset, baseUtcOffset + rule.DaylightDelta};
 509                         else
 510                                 return new TimeSpan[] {baseUtcOffset, baseUtcOffset};
 511                 }
 512
 513                 public TimeSpan [] GetAmbiguousTimeOffsets (DateTimeOffset dateTimeOffset)
 514                 {
 515                         if (!IsAmbiguousTime (dateTimeOffset))
 516                                 throw new ArgumentException ("dateTimeOffset is not an ambiguous time");
 517
 518                         throw new NotImplementedException ();
 519                 }
 520
 521                 public override int GetHashCode ()
 522                 {
 523                         int hash_code = Id.GetHashCode ();
 524                         foreach (AdjustmentRule rule in GetAdjustmentRules ())
 525                                 hash_code ^= rule.GetHashCode ();
 526                         return hash_code;
 527                 }
 528
 529 #if NET_4_0
 530                 void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
 531 #else
 532                 public void GetObjectData (SerializationInfo info, StreamingContext context)
 533 #endif
 534                 {
 535                         throw new NotImplementedException ();
 536                 }
 537
 538                 //FIXME: change this to a generic Dictionary and allow caching for FindSystemTimeZoneById
 539                 private static List<TimeZoneInfo> systemTimeZones = null;
 540                 public static ReadOnlyCollection<TimeZoneInfo> GetSystemTimeZones ()
 541                 {
 542                         if (systemTimeZones == null) {
 543                                 systemTimeZones = new List<TimeZoneInfo> ();
 544 #if !NET_2_1
 545                                 if (TimeZoneKey != null) {
 546                                         foreach (string id in TimeZoneKey.GetSubKeyNames ()) {
 547                                                 try {
 548                                                         systemTimeZones.Add (FindSystemTimeZoneById (id));
 549                                                 } catch {}
 550                                         }
 551
 552                                         return new ReadOnlyCollection<TimeZoneInfo> (systemTimeZones);
 553                                 }
 554 #endif
 555 #if MONODROID
 556                         foreach (string id in ZoneInfoDB.GetAvailableIds ()) {
 557                                 systemTimeZones.Add (ZoneInfoDB.GetTimeZone (id));
 558                         }
 559 #elif MONOTOUCH
 560                                 if (systemTimeZones.Count == 0) {
 561                                         foreach (string name in GetMonoTouchNames ()) {
 562                                                 using (Stream stream = GetMonoTouchData (name)) {
 563                                                         systemTimeZones.Add (BuildFromStream (name, stream));
 564                                                 }
 565                                         }
 566                                 }
 567 #elif LIBC
 568                                 string[] continents = new string [] {"Africa", "America", "Antarctica", "Arctic", "Asia", "Atlantic", "Brazil", "Canada", "Chile", "Europe", "Indian", "Mexico", "Mideast", "Pacific", "US"};
 569                                 foreach (string continent in continents) {
 570                                         try {
 571                                                 foreach (string zonepath in Directory.GetFiles (Path.Combine (TimeZoneDirectory, continent))) {
 572                                                         try {
 573                                                                 string id = String.Format ("{0}/{1}", continent, Path.GetFileName (zonepath));
 574                                                                 systemTimeZones.Add (FindSystemTimeZoneById (id));
 575                                                         } catch (ArgumentNullException) {
 576                                                         } catch (TimeZoneNotFoundException) {
 577                                                         } catch (InvalidTimeZoneException) {
 578                                                         } catch (Exception) {
 579                                                                 throw;
 580                                                         }
 581                                                 }
 582                                         } catch {}
 583                                 }
 584 #else
 585                                 throw new NotImplementedException ("This method is not implemented for this platform");
 586 #endif
 587                         }
 588                         return new ReadOnlyCollection<TimeZoneInfo> (systemTimeZones);
 589                 }
 590
 591                 public TimeSpan GetUtcOffset (DateTime dateTime)
 592                 {
 593                         if (IsDaylightSavingTime (dateTime)) {
 594                                 AdjustmentRule rule = GetApplicableRule (dateTime);
 595                                 if (rule != null)
 596                                         return BaseUtcOffset + rule.DaylightDelta;
 597                         }
 598
 599                         return BaseUtcOffset;
 600                 }
 601
 602                 public TimeSpan GetUtcOffset (DateTimeOffset dateTimeOffset)
 603                 {
 604                         throw new NotImplementedException ();
 605                 }
 606
 607                 public bool HasSameRules (TimeZoneInfo other)
 608                 {
 609                         if (other == null)
 610                                 throw new ArgumentNullException ("other");
 611
 612                         if ((this.adjustmentRules == null) != (other.adjustmentRules == null))
 613                                 return false;
 614
 615                         if (this.adjustmentRules == null)
 616                                 return true;
 617
 618                         if (this.BaseUtcOffset != other.BaseUtcOffset)
 619                                 return false;
 620
 621                         if (this.adjustmentRules.Length != other.adjustmentRules.Length)
 622                                 return false;
 623
 624                         for (int i = 0; i < adjustmentRules.Length; i++) {
 625                                 if (! (this.adjustmentRules [i]).Equals (other.adjustmentRules [i]))
 626                                         return false;
 627                         }
 628
 629                         return true;
 630                 }
 631
 632                 public bool IsAmbiguousTime (DateTime dateTime)
 633                 {
 634                         if (dateTime.Kind == DateTimeKind.Local && IsInvalidTime (dateTime))
 635                                 throw new ArgumentException ("Kind is Local and time is Invalid");
 636
 637                         if (this == TimeZoneInfo.Utc)
 638                                 return false;
 639
 640                         if (dateTime.Kind == DateTimeKind.Utc)
 641                                 dateTime = ConvertTimeFromUtc (dateTime);
 642
 643                         if (dateTime.Kind == DateTimeKind.Local && this != TimeZoneInfo.Local)
 644                                 dateTime = ConvertTime (dateTime, TimeZoneInfo.Local, this);
 645
 646                         AdjustmentRule rule = GetApplicableRule (dateTime);
 647                         if (rule != null) {
 648                                 DateTime tpoint = TransitionPoint (rule.DaylightTransitionEnd, dateTime.Year);
 649                                 if (dateTime > tpoint - rule.DaylightDelta  && dateTime <= tpoint)
 650                                         return true;
 651                         }
 652
 653                         return false;
 654                 }
 655
 656                 public bool IsAmbiguousTime (DateTimeOffset dateTimeOffset)
 657                 {
 658                         throw new NotImplementedException ();
 659                 }
 660
 661                 public bool IsDaylightSavingTime (DateTime dateTime)
 662                 {
 663                         if (dateTime.Kind == DateTimeKind.Local && IsInvalidTime (dateTime))
 664                                 throw new ArgumentException ("dateTime is invalid and Kind is Local");
 665
 666                         if (this == TimeZoneInfo.Utc)
 667                                 return false;
 668
 669                         if (!SupportsDaylightSavingTime)
 670                                 return false;
 671                         //FIXME: do not rely on DateTime implementation !
 672                         if ((dateTime.Kind == DateTimeKind.Local || dateTime.Kind == DateTimeKind.Unspecified) && this == TimeZoneInfo.Local)
 673                                 return dateTime.IsDaylightSavingTime ();
 674
 675                         //FIXME: do not rely on DateTime implementation !
 676                         if (dateTime.Kind == DateTimeKind.Local && this != TimeZoneInfo.Utc)
 677                                 return IsDaylightSavingTime (DateTime.SpecifyKind (dateTime.ToUniversalTime (), DateTimeKind.Utc));
 678
 679                         AdjustmentRule rule = GetApplicableRule (dateTime.Date);
 680                         if (rule == null)
 681                                 return false;
 682
 683                         DateTime DST_start = TransitionPoint (rule.DaylightTransitionStart, dateTime.Year);
 684                         DateTime DST_end = TransitionPoint (rule.DaylightTransitionEnd, dateTime.Year + ((rule.DaylightTransitionStart.Month < rule.DaylightTransitionEnd.Month) ? 0 : 1));
 685                         if (dateTime.Kind == DateTimeKind.Utc) {
 686                                 DST_start -= BaseUtcOffset;
 687                                 DST_end -= (BaseUtcOffset + rule.DaylightDelta);
 688                         }
 689
 690                         return (dateTime >= DST_start && dateTime < DST_end);
 691                 }
 692
 693                 public bool IsDaylightSavingTime (DateTimeOffset dateTimeOffset)
 694                 {
 695                         throw new NotImplementedException ();
 696                 }
 697
 698                 public bool IsInvalidTime (DateTime dateTime)
 699                 {
 700                         if (dateTime.Kind == DateTimeKind.Utc)
 701                                 return false;
 702                         if (dateTime.Kind == DateTimeKind.Local && this != Local)
 703                                 return false;
 704
 705                         AdjustmentRule rule = GetApplicableRule (dateTime);
 706                         if (rule != null) {
 707                                 DateTime tpoint = TransitionPoint (rule.DaylightTransitionStart, dateTime.Year);
 708                                 if (dateTime >= tpoint && dateTime < tpoint + rule.DaylightDelta)
 709                                         return true;
 710                         }
 711
 712                         return false;
 713                 }
 714
 715 #if NET_4_0
 716                 void IDeserializationCallback.OnDeserialization (object sender)
 717 #else
 718                 public void OnDeserialization (object sender)
 719 #endif
 720                 {
 721                         throw new NotImplementedException ();
 722                 }
 723
 724                 public string ToSerializedString ()
 725                 {
 726                         throw new NotImplementedException ();
 727                 }
 728
 729                 public override string ToString ()
 730                 {
 731                         return DisplayName;
 732                 }
 733
 734                 private TimeZoneInfo (string id, TimeSpan baseUtcOffset, string displayName, string standardDisplayName, string daylightDisplayName, TimeZoneInfo.AdjustmentRule [] adjustmentRules, bool disableDaylightSavingTime)
 735                 {
 736                         if (id == null)
 737                                 throw new ArgumentNullException ("id");
 738
 739                         if (id == String.Empty)
 740                                 throw new ArgumentException ("id parameter is an empty string");
 741
 742                         if (baseUtcOffset.Ticks % TimeSpan.TicksPerMinute != 0)
 743                                 throw new ArgumentException ("baseUtcOffset parameter does not represent a whole number of minutes");
 744
 745                         if (baseUtcOffset > new TimeSpan (14, 0, 0) || baseUtcOffset < new TimeSpan (-14, 0, 0))
 746                                 throw new ArgumentOutOfRangeException ("baseUtcOffset parameter is greater than 14 hours or less than -14 hours");
 747
 748 #if STRICT
 749                         if (id.Length > 32)
 750                                 throw new ArgumentException ("id parameter shouldn't be longer than 32 characters");
 751 #endif
 752
 753                         if (adjustmentRules != null && adjustmentRules.Length != 0) {
 754                                 AdjustmentRule prev = null;
 755                                 foreach (AdjustmentRule current in adjustmentRules) {
 756                                         if (current == null)
 757                                                 throw new InvalidTimeZoneException ("one or more elements in adjustmentRules are null");
 758
 759                                         if ((baseUtcOffset + current.DaylightDelta < new TimeSpan (-14, 0, 0)) ||
 760                                                         (baseUtcOffset + current.DaylightDelta > new TimeSpan (14, 0, 0)))
 761                                                 throw new InvalidTimeZoneException ("Sum of baseUtcOffset and DaylightDelta of one or more object in adjustmentRules array is greater than 14 or less than -14 hours;");
 762
 763                                         if (prev != null && prev.DateStart > current.DateStart)
 764                                                 throw new InvalidTimeZoneException ("adjustment rules specified in adjustmentRules parameter are not in chronological order");
 765
 766                                         if (prev != null && prev.DateEnd > current.DateStart)
 767                                                 throw new InvalidTimeZoneException ("some adjustment rules in the adjustmentRules parameter overlap");
 768
 769                                         if (prev != null && prev.DateEnd == current.DateStart)
 770                                                 throw new InvalidTimeZoneException ("a date can have multiple adjustment rules applied to it");
 771
 772                                         prev = current;
 773                                 }
 774                         }
 775
 776                         this.id = id;
 777                         this.baseUtcOffset = baseUtcOffset;
 778                         this.displayName = displayName ?? id;
 779                         this.standardDisplayName = standardDisplayName ?? id;
 780                         this.daylightDisplayName = daylightDisplayName;
 781                         this.disableDaylightSavingTime = disableDaylightSavingTime;
 782                         this.adjustmentRules = adjustmentRules;
 783                 }
 784
 785                 private AdjustmentRule GetApplicableRule (DateTime dateTime)
 786                 {
 787                         //Transitions are always in standard time
 788                         DateTime date = dateTime;
 789
 790                         if (dateTime.Kind == DateTimeKind.Local && this != TimeZoneInfo.Local)
 791                                 date = date.ToUniversalTime () + BaseUtcOffset;
 792
 793                         if (dateTime.Kind == DateTimeKind.Utc && this != TimeZoneInfo.Utc)
 794                                 date = date + BaseUtcOffset;
 795
 796                         if (adjustmentRules != null) {
 797                                 foreach (AdjustmentRule rule in adjustmentRules) {
 798                                         if (rule.DateStart > date.Date)
 799                                                 return null;
 800                                         if (rule.DateEnd < date.Date)
 801                                                 continue;
 802                                         return rule;
 803                                 }
 804                         }
 805                         return null;
 806                 }
 807
 808                 private static DateTime TransitionPoint (TransitionTime transition, int year)
 809                 {
 810                         if (transition.IsFixedDateRule)
 811                                 return new DateTime (year, transition.Month, transition.Day) + transition.TimeOfDay.TimeOfDay;
 812
 813                         DayOfWeek first = (new DateTime (year, transition.Month, 1)).DayOfWeek;
 814                         int day = 1 + (transition.Week - 1) * 7 + (transition.DayOfWeek - first) % 7;
 815                         if (day >  DateTime.DaysInMonth (year, transition.Month))
 816                                 day -= 7;
 817                         return new DateTime (year, transition.Month, day) + transition.TimeOfDay.TimeOfDay;
 818                 }
 819
 820                 static List<AdjustmentRule> ValidateRules (List<AdjustmentRule> adjustmentRules)
 821                 {
 822                         AdjustmentRule prev = null;
 823                         foreach (AdjustmentRule current in adjustmentRules.ToArray ()) {
 824                                 if (prev != null && prev.DateEnd > current.DateStart) {
 825                                         adjustmentRules.Remove (current);
 826                                 }
 827                                 prev = current;
 828                         }
 829                         return adjustmentRules;
 830                 }
 831
 832 #if LIBC || MONODROID
 833                 private static bool ValidTZFile (byte [] buffer, int length)
 834                 {
 835                         StringBuilder magic = new StringBuilder ();
 836
 837                         for (int i = 0; i < 4; i++)
 838                                 magic.Append ((char)buffer [i]);
 839
 840                         if (magic.ToString () != "TZif")
 841                                 return false;
 842
 843                         if (length >= BUFFER_SIZE)
 844                                 return false;
 845
 846                         return true;
 847                 }
 848
 849                 static int SwapInt32 (int i)
 850                 {
 851                         return (((i >> 24) & 0xff)
 852                                 | ((i >> 8) & 0xff00)
 853                                 | ((i << 8) & 0xff0000)
 854                                 | ((i << 24)));
 855                 }
 856
 857                 static int ReadBigEndianInt32 (byte [] buffer, int start)
 858                 {
 859                         int i = BitConverter.ToInt32 (buffer, start);
 860                         if (!BitConverter.IsLittleEndian)
 861                                 return i;
 862
 863                         return SwapInt32 (i);
 864                 }
 865
 866                 private static TimeZoneInfo ParseTZBuffer (string id, byte [] buffer, int length)
 867                 {
 868                         //Reading the header. 4 bytes for magic, 16 are reserved
 869                         int ttisgmtcnt = ReadBigEndianInt32 (buffer, 20);
 870                         int ttisstdcnt = ReadBigEndianInt32 (buffer, 24);
 871                         int leapcnt = ReadBigEndianInt32 (buffer, 28);
 872                         int timecnt = ReadBigEndianInt32 (buffer, 32);
 873                         int typecnt = ReadBigEndianInt32 (buffer, 36);
 874                         int charcnt = ReadBigEndianInt32 (buffer, 40);
 875
 876                         if (length < 44 + timecnt * 5 + typecnt * 6 + charcnt + leapcnt * 8 + ttisstdcnt + ttisgmtcnt)
 877                                 throw new InvalidTimeZoneException ();
 878
 879                         Dictionary<int, string> abbreviations = ParseAbbreviations (buffer, 44 + 4 * timecnt + timecnt + 6 * typecnt, charcnt);
 880                         Dictionary<int, TimeType> time_types = ParseTimesTypes (buffer, 44 + 4 * timecnt + timecnt, typecnt, abbreviations);
 881                         List<KeyValuePair<DateTime, TimeType>> transitions = ParseTransitions (buffer, 44, timecnt, time_types);
 882
 883                         if (time_types.Count == 0)
 884                                 throw new InvalidTimeZoneException ();
 885
 886                         if (time_types.Count == 1 && ((TimeType)time_types[0]).IsDst)
 887                                 throw new InvalidTimeZoneException ();
 888
 889                         TimeSpan baseUtcOffset = new TimeSpan (0);
 890                         TimeSpan dstDelta = new TimeSpan (0);
 891                         string standardDisplayName = null;
 892                         string daylightDisplayName = null;
 893                         bool dst_observed = false;
 894                         DateTime dst_start = DateTime.MinValue;
 895                         List<AdjustmentRule> adjustmentRules = new List<AdjustmentRule> ();
 896
 897                         for (int i = 0; i < transitions.Count; i++) {
 898                                 var pair = transitions [i];
 899                                 DateTime ttime = pair.Key;
 900                                 TimeType ttype = pair.Value;
 901                                 if (!ttype.IsDst) {
 902                                         if (standardDisplayName != ttype.Name || baseUtcOffset.TotalSeconds != ttype.Offset) {
 903                                                 standardDisplayName = ttype.Name;
 904                                                 daylightDisplayName = null;
 905                                                 baseUtcOffset = new TimeSpan (0, 0, ttype.Offset);
 906                                                 adjustmentRules = new List<AdjustmentRule> ();
 907                                                 dst_observed = false;
 908                                         }
 909                                         if (dst_observed) {
 910                                                 //FIXME: check additional fields for this:
 911                                                 //most of the transitions are expressed in GMT
 912                                                 dst_start += baseUtcOffset;
 913                                                 DateTime dst_end = ttime + baseUtcOffset + dstDelta;
 914
 915                                                 //some weird timezone (America/Phoenix) have end dates on Jan 1st
 916                                                 if (dst_end.Date == new DateTime (dst_end.Year, 1, 1) && dst_end.Year > dst_start.Year)
 917                                                         dst_end -= new TimeSpan (24, 0, 0);
 918
 919                                                 DateTime dateStart, dateEnd;
 920                                                 if (dst_start.Month < 7)
 921                                                         dateStart = new DateTime (dst_start.Year, 1, 1);
 922                                                 else
 923                                                         dateStart = new DateTime (dst_start.Year, 7, 1);
 924
 925                                                 if (dst_end.Month >= 7)
 926                                                         dateEnd = new DateTime (dst_end.Year, 12, 31);
 927                                                 else
 928                                                         dateEnd = new DateTime (dst_end.Year, 6, 30);
 929
 930
 931                                                 TransitionTime transition_start = TransitionTime.CreateFixedDateRule (new DateTime (1, 1, 1) + dst_start.TimeOfDay, dst_start.Month, dst_start.Day);
 932                                                 TransitionTime transition_end = TransitionTime.CreateFixedDateRule (new DateTime (1, 1, 1) + dst_end.TimeOfDay, dst_end.Month, dst_end.Day);
 933                                                 if  (transition_start != transition_end) //y, that happened in Argentina in 1943-1946
 934                                                         adjustmentRules.Add (AdjustmentRule.CreateAdjustmentRule (dateStart, dateEnd, dstDelta, transition_start, transition_end));
 935                                         }
 936                                         dst_observed = false;
 937                                 } else {
 938                                         if (daylightDisplayName != ttype.Name || dstDelta.TotalSeconds != ttype.Offset - baseUtcOffset.TotalSeconds) {
 939                                                 daylightDisplayName = ttype.Name;
 940                                                 dstDelta = new TimeSpan(0, 0, ttype.Offset) - baseUtcOffset;
 941                                         }
 942                                         dst_start = ttime;
 943                                         dst_observed = true;
 944                                 }
 945                         }
 946
 947                         if (adjustmentRules.Count == 0) {
 948                                 TimeType t = (TimeType)time_types [0];
 949                                 if (standardDisplayName == null) {
 950                                         standardDisplayName = t.Name;
 951                                         baseUtcOffset = new TimeSpan (0, 0, t.Offset);
 952                                 }
 953                                 return CreateCustomTimeZone (id, baseUtcOffset, id, standardDisplayName);
 954                         } else {
 955                                 return CreateCustomTimeZone (id, baseUtcOffset, id, standardDisplayName, daylightDisplayName, ValidateRules (adjustmentRules).ToArray ());
 956                         }
 957                 }
 958
 959                 static Dictionary<int, string> ParseAbbreviations (byte [] buffer, int index, int count)
 960                 {
 961                         var abbrevs = new Dictionary<int, string> ();
 962                         int abbrev_index = 0;
 963                         var sb = new StringBuilder ();
 964                         for (int i = 0; i < count; i++) {
 965                                 char c = (char) buffer [index + i];
 966                                 if (c != '\0')
 967                                         sb.Append (c);
 968                                 else {
 969                                         abbrevs.Add (abbrev_index, sb.ToString ());
 970                                         //Adding all the substrings too, as it seems to be used, at least for Africa/Windhoek
 971                                         for (int j = 1; j < sb.Length; j++)
 972                                                 abbrevs.Add (abbrev_index + j, sb.ToString (j, sb.Length - j));
 973                                         abbrev_index = i + 1;
 974                                         sb = new StringBuilder ();
 975                                 }
 976                         }
 977                         return abbrevs;
 978                 }
 979
 980                 static Dictionary<int, TimeType> ParseTimesTypes (byte [] buffer, int index, int count, Dictionary<int, string> abbreviations)
 981                 {
 982                         var types = new Dictionary<int, TimeType> (count);
 983                         for (int i = 0; i < count; i++) {
 984                                 int offset = ReadBigEndianInt32 (buffer, index + 6 * i);
 985                                 byte is_dst = buffer [index + 6 * i + 4];
 986                                 byte abbrev = buffer [index + 6 * i + 5];
 987                                 types.Add (i, new TimeType (offset, (is_dst != 0), abbreviations [(int)abbrev]));
 988                         }
 989                         return types;
 990                 }
 991
 992                 static List<KeyValuePair<DateTime, TimeType>> ParseTransitions (byte [] buffer, int index, int count, Dictionary<int, TimeType> time_types)
 993                 {
 994                         var list = new List<KeyValuePair<DateTime, TimeType>> (count);
 995                         for (int i = 0; i < count; i++) {
 996                                 int unixtime = ReadBigEndianInt32 (buffer, index + 4 * i);
 997                                 DateTime ttime = DateTimeFromUnixTime (unixtime);
 998                                 byte ttype = buffer [index + 4 * count + i];
 999                                 list.Add (new KeyValuePair<DateTime, TimeType> (ttime, time_types [(int)ttype]));
1000                         }
1001                         return list;
1002                 }
1003
1004                 static DateTime DateTimeFromUnixTime (long unix_time)
1005                 {
1006                         DateTime date_time = new DateTime (1970, 1, 1);
1007                         return date_time.AddSeconds (unix_time);
1008                 }
1009         }
1010
1011         struct TimeType {
1012                 public readonly int Offset;
1013                 public readonly bool IsDst;
1014                 public string Name;
1015
1016                 public TimeType (int offset, bool is_dst, string abbrev)
1017                 {
1018                         this.Offset = offset;
1019                         this.IsDst = is_dst;
1020                         this.Name = abbrev;
1021                 }
1022
1023                 public override string ToString ()
1024                 {
1025                         return "offset: " + Offset + "s, is_dst: " + IsDst + ", zone name: " + Name;
1026                 }
1027 #else
1028         }
1029 #endif
1030         }
1031 }
1032
1033 #endif