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

   1
   2 /*
   3  * System.TimeZoneInfo
   4  *
   5  * Author(s)
   6  *      Stephane Delcroix <stephane@delcroix.org>
   7  *
   8  * Copyright 2011 Xamarin Inc.
   9  *
  10  * Permission is hereby granted, free of charge, to any person obtaining
  11  * a copy of this software and associated documentation files (the
  12  * "Software"), to deal in the Software without restriction, including
  13  * without limitation the rights to use, copy, modify, merge, publish,
  14  * distribute, sublicense, and/or sell copies of the Software, and to
  15  * permit persons to whom the Software is furnished to do so, subject to
  16  * the following conditions:
  17  *
  18  * The above copyright notice and this permission notice shall be
  19  * included in all copies or substantial portions of the Software.
  20  *
  21  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  22  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  23  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  24  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  25  * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  26  * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  27  * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  28  */
  29
  30 using System;
  31 using System.Runtime.CompilerServices;
  32 using System.Threading;
  33
  34 #if !INSIDE_CORLIB && NET_4_0
  35
  36 [assembly:TypeForwardedTo (typeof(TimeZoneInfo))]
  37
  38 #elif (INSIDE_CORLIB && NET_4_0) || (!INSIDE_CORLIB && (NET_3_5 && !NET_4_0 && !MOBILE))
  39
  40 using System.Collections.Generic;
  41 using System.Collections.ObjectModel;
  42 using System.Runtime.Serialization;
  43 using System.Text;
  44
  45 #if LIBC || MONODROID
  46 using System.IO;
  47 using Mono;
  48 #endif
  49
  50 using Microsoft.Win32;
  51
  52 namespace System
  53 {
  54 #if MOBILE
  55         [TypeForwardedFrom (Consts.AssemblySystem_Core)]
  56 #elif NET_4_0
  57         [TypeForwardedFrom (Consts.AssemblySystemCore_3_5)]
  58 #endif
  59         [SerializableAttribute]
  60         public sealed partial class TimeZoneInfo : IEquatable<TimeZoneInfo>, ISerializable, IDeserializationCallback
  61         {
  62                 TimeSpan baseUtcOffset;
  63                 public TimeSpan BaseUtcOffset {
  64                         get { return baseUtcOffset; }
  65                 }
  66
  67                 string daylightDisplayName;
  68                 public string DaylightName {
  69                         get {
  70                                 return supportsDaylightSavingTime
  71                                         ? daylightDisplayName
  72                                         : string.Empty;
  73                         }
  74                 }
  75
  76                 string displayName;
  77                 public string DisplayName {
  78                         get { return displayName; }
  79                 }
  80
  81                 string id;
  82                 public string Id {
  83                         get { return id; }
  84                 }
  85
  86                 static TimeZoneInfo local;
  87                 public static TimeZoneInfo Local {
  88                         get {
  89                                 var l = local;
  90                                 if (l == null) {
  91                                         l = CreateLocal ();
  92                                         if (l == null)
  93                                                 throw new TimeZoneNotFoundException ();
  94
  95                                         if (Interlocked.CompareExchange (ref local, l, null) != null)
  96                                                 l = local;
  97                                 }
  98
  99                                 return l;
 100                         }
 101                 }
 102
 103                 static TimeZoneInfo CreateLocal ()
 104                 {
 105 #if MONODROID
 106                         return AndroidTimeZones.Default;
 107 #elif MONOTOUCH
 108                         using (Stream stream = GetMonoTouchData (null)) {
 109                                 return BuildFromStream ("Local", stream);
 110                         }
 111 #elif LIBC
 112                         try {
 113                                 return FindSystemTimeZoneByFileName ("Local", "/etc/localtime");
 114                         } catch {
 115                                 try {
 116                                         return FindSystemTimeZoneByFileName ("Local", Path.Combine (TimeZoneDirectory, "localtime"));
 117                                 } catch {
 118                                         return null;
 119                                 }
 120                         }
 121 #else
 122                         if (IsWindows && LocalZoneKey != null) {
 123                                 string name = (string)LocalZoneKey.GetValue ("TimeZoneKeyName");
 124                                 name = TrimSpecial (name);
 125                                 if (name != null)
 126                                         return TimeZoneInfo.FindSystemTimeZoneById (name);
 127                         }
 128
 129                         return null;
 130 #endif
 131                 }
 132
 133                 string standardDisplayName;
 134                 public string StandardName {
 135                         get { return standardDisplayName; }
 136                 }
 137
 138                 bool supportsDaylightSavingTime;
 139                 public bool SupportsDaylightSavingTime {
 140                         get  { return supportsDaylightSavingTime; }
 141                 }
 142
 143                 static TimeZoneInfo utc;
 144                 public static TimeZoneInfo Utc {
 145                         get {
 146                                 if (utc == null)
 147                                         utc = CreateCustomTimeZone ("UTC", new TimeSpan (0), "UTC", "UTC");
 148                                 return utc;
 149                         }
 150                 }
 151 #if LIBC
 152                 static string timeZoneDirectory;
 153                 static string TimeZoneDirectory {
 154                         get {
 155                                 if (timeZoneDirectory == null)
 156                                         timeZoneDirectory = "/usr/share/zoneinfo";
 157                                 return timeZoneDirectory;
 158                         }
 159                         set {
 160                                 ClearCachedData ();
 161                                 timeZoneDirectory = value;
 162                         }
 163                 }
 164 #endif
 165                 private AdjustmentRule [] adjustmentRules;
 166
 167 #if !NET_2_1
 168                 /// <summary>
 169                 /// Determine whether windows of not (taken Stephane Delcroix's code)
 170                 /// </summary>
 171                 private static bool IsWindows
 172                 {
 173                         get {
 174                                 int platform = (int) Environment.OSVersion.Platform;
 175                                 return ((platform != 4) && (platform != 6) && (platform != 128));
 176                         }
 177                 }
 178
 179                 /// <summary>
 180                 /// Needed to trim misc garbage in MS registry keys
 181                 /// </summary>
 182                 private static string TrimSpecial (string str)
 183                 {
 184                         var Istart = 0;
 185                         while (Istart < str.Length && !char.IsLetterOrDigit(str[Istart])) Istart++;
 186                         var Iend = str.Length - 1;
 187                         while (Iend > Istart && !char.IsLetterOrDigit(str[Iend])) Iend--;
 188
 189                         return str.Substring (Istart, Iend-Istart+1);
 190                 }
 191
 192                 static RegistryKey timeZoneKey;
 193                 static RegistryKey TimeZoneKey {
 194                         get {
 195                                 if (timeZoneKey != null)
 196                                         return timeZoneKey;
 197                                 if (!IsWindows)
 198                                         return null;
 199
 200                                 return timeZoneKey = Registry.LocalMachine.OpenSubKey (
 201                                         "SOFTWARE\\Microsoft\\Windows NT\\CurrentVersion\\Time Zones",
 202                                         false);
 203                         }
 204                 }
 205
 206                 static RegistryKey localZoneKey;
 207                 static RegistryKey LocalZoneKey {
 208                         get {
 209                                 if (localZoneKey != null)
 210                                         return localZoneKey;
 211
 212                                 if (!IsWindows)
 213                                         return null;
 214
 215                                 return localZoneKey = Registry.LocalMachine.OpenSubKey (
 216                                         "SYSTEM\\CurrentControlSet\\Control\\TimeZoneInformation", false);
 217                         }
 218                 }
 219 #endif
 220
 221                 public static void ClearCachedData ()
 222                 {
 223                         local = null;
 224                         utc = null;
 225                         systemTimeZones = null;
 226                 }
 227
 228                 public static DateTime ConvertTime (DateTime dateTime, TimeZoneInfo destinationTimeZone)
 229                 {
 230                         return ConvertTime (dateTime, TimeZoneInfo.Local, destinationTimeZone);
 231                 }
 232
 233                 public static DateTime ConvertTime (DateTime dateTime, TimeZoneInfo sourceTimeZone, TimeZoneInfo destinationTimeZone)
 234                 {
 235                         if (dateTime.Kind == DateTimeKind.Local && sourceTimeZone != TimeZoneInfo.Local)
 236                                 throw new ArgumentException ("Kind property of dateTime is Local but the sourceTimeZone does not equal TimeZoneInfo.Local");
 237
 238                         if (dateTime.Kind == DateTimeKind.Utc && sourceTimeZone != TimeZoneInfo.Utc)
 239                                 throw new ArgumentException ("Kind property of dateTime is Utc but the sourceTimeZone does not equal TimeZoneInfo.Utc");
 240
 241                         if (sourceTimeZone.IsInvalidTime (dateTime))
 242                                 throw new ArgumentException ("dateTime parameter is an invalid time");
 243
 244                         if (sourceTimeZone == null)
 245                                 throw new ArgumentNullException ("sourceTimeZone");
 246
 247                         if (destinationTimeZone == null)
 248                                 throw new ArgumentNullException ("destinationTimeZone");
 249
 250                         if (dateTime.Kind == DateTimeKind.Local && sourceTimeZone == TimeZoneInfo.Local && destinationTimeZone == TimeZoneInfo.Local)
 251                                 return dateTime;
 252
 253                         DateTime utc = ConvertTimeToUtc (dateTime);
 254
 255                         if (destinationTimeZone == TimeZoneInfo.Utc)
 256                                 return utc;
 257
 258                         return ConvertTimeFromUtc (utc, destinationTimeZone);
 259
 260                 }
 261
 262                 public static DateTimeOffset ConvertTime(DateTimeOffset dateTimeOffset, TimeZoneInfo destinationTimeZone)
 263                 {
 264                         if (destinationTimeZone == null)
 265                                 throw new ArgumentNullException("destinationTimeZone");
 266
 267                         var utcDateTime = dateTimeOffset.UtcDateTime;
 268                         AdjustmentRule rule = destinationTimeZone.GetApplicableRule (utcDateTime);
 269
 270                         if (rule != null && destinationTimeZone.IsDaylightSavingTime(utcDateTime)) {
 271                                 var offset = destinationTimeZone.BaseUtcOffset + rule.DaylightDelta;
 272                                 return new DateTimeOffset(DateTime.SpecifyKind(utcDateTime, DateTimeKind.Unspecified) + offset, offset);
 273                         }
 274                         else {
 275                                 return new DateTimeOffset(DateTime.SpecifyKind(utcDateTime, DateTimeKind.Unspecified) + destinationTimeZone.BaseUtcOffset, destinationTimeZone.BaseUtcOffset);
 276                         }
 277                 }
 278
 279                 public static DateTime ConvertTimeBySystemTimeZoneId (DateTime dateTime, string destinationTimeZoneId)
 280                 {
 281                         return ConvertTime (dateTime, FindSystemTimeZoneById (destinationTimeZoneId));
 282                 }
 283
 284                 public static DateTime ConvertTimeBySystemTimeZoneId (DateTime dateTime, string sourceTimeZoneId, string destinationTimeZoneId)
 285                 {
 286                         return ConvertTime (dateTime, FindSystemTimeZoneById (sourceTimeZoneId), FindSystemTimeZoneById (destinationTimeZoneId));
 287                 }
 288
 289                 public static DateTimeOffset ConvertTimeBySystemTimeZoneId (DateTimeOffset dateTimeOffset, string destinationTimeZoneId)
 290                 {
 291                         return ConvertTime (dateTimeOffset, FindSystemTimeZoneById (destinationTimeZoneId));
 292                 }
 293
 294                 private DateTime ConvertTimeFromUtc (DateTime dateTime)
 295                 {
 296                         if (dateTime.Kind == DateTimeKind.Local)
 297                                 throw new ArgumentException ("Kind property of dateTime is Local");
 298
 299                         if (this == TimeZoneInfo.Utc)
 300                                 return DateTime.SpecifyKind (dateTime, DateTimeKind.Utc);
 301
 302                         //FIXME: do not rely on DateTime implementation !
 303                         if (this == TimeZoneInfo.Local)
 304                         {
 305 #if NET_4_0
 306                                 return dateTime.ToLocalTime ();
 307 #else
 308                                 return DateTime.SpecifyKind (dateTime.ToLocalTime (), DateTimeKind.Unspecified);
 309 #endif
 310                         }
 311
 312
 313                         AdjustmentRule rule = GetApplicableRule (dateTime);
 314
 315                         if (rule != null && IsDaylightSavingTime (DateTime.SpecifyKind (dateTime, DateTimeKind.Utc)))
 316                                 return DateTime.SpecifyKind (dateTime + BaseUtcOffset + rule.DaylightDelta , DateTimeKind.Unspecified);
 317                         else
 318                                 return DateTime.SpecifyKind (dateTime + BaseUtcOffset, DateTimeKind.Unspecified);
 319                 }
 320
 321                 public static DateTime ConvertTimeFromUtc (DateTime dateTime, TimeZoneInfo destinationTimeZone)
 322                 {
 323                         if (destinationTimeZone == null)
 324                                 throw new ArgumentNullException ("destinationTimeZone");
 325
 326                         return destinationTimeZone.ConvertTimeFromUtc (dateTime);
 327                 }
 328
 329                 public static DateTime ConvertTimeToUtc (DateTime dateTime)
 330                 {
 331                         if (dateTime.Kind == DateTimeKind.Utc)
 332                                 return dateTime;
 333
 334                         //FIXME: do not rely on DateTime implementation !
 335                         return DateTime.SpecifyKind (dateTime.ToUniversalTime (), DateTimeKind.Utc);
 336                 }
 337
 338                 public static DateTime ConvertTimeToUtc (DateTime dateTime, TimeZoneInfo sourceTimeZone)
 339                 {
 340                         if (sourceTimeZone == null)
 341                                 throw new ArgumentNullException ("sourceTimeZone");
 342
 343                         if (dateTime.Kind == DateTimeKind.Utc && sourceTimeZone != TimeZoneInfo.Utc)
 344                                 throw new ArgumentException ("Kind property of dateTime is Utc but the sourceTimeZone does not equal TimeZoneInfo.Utc");
 345
 346                         if (dateTime.Kind == DateTimeKind.Local && sourceTimeZone != TimeZoneInfo.Local)
 347                                 throw new ArgumentException ("Kind property of dateTime is Local but the sourceTimeZone does not equal TimeZoneInfo.Local");
 348
 349                         if (sourceTimeZone.IsInvalidTime (dateTime))
 350                                 throw new ArgumentException ("dateTime parameter is an invalid time");
 351
 352                         if (dateTime.Kind == DateTimeKind.Utc && sourceTimeZone == TimeZoneInfo.Utc)
 353                                 return dateTime;
 354
 355                         if (dateTime.Kind == DateTimeKind.Utc)
 356                                 return dateTime;
 357
 358                         if (dateTime.Kind == DateTimeKind.Local)
 359                                 return ConvertTimeToUtc (dateTime);
 360
 361                         if (sourceTimeZone.IsAmbiguousTime (dateTime) || !sourceTimeZone.IsDaylightSavingTime (dateTime))
 362                                 return DateTime.SpecifyKind (dateTime - sourceTimeZone.BaseUtcOffset, DateTimeKind.Utc);
 363                         else {
 364                                 AdjustmentRule rule = sourceTimeZone.GetApplicableRule (dateTime);
 365                                 if (rule != null)
 366                                         return DateTime.SpecifyKind (dateTime - sourceTimeZone.BaseUtcOffset - rule.DaylightDelta, DateTimeKind.Utc);
 367                                 else
 368                                         return DateTime.SpecifyKind (dateTime - sourceTimeZone.BaseUtcOffset, DateTimeKind.Utc);
 369                         }
 370                 }
 371
 372                 public static TimeZoneInfo CreateCustomTimeZone (string id, TimeSpan baseUtcOffset, string displayName, string standardDisplayName)
 373                 {
 374                         return CreateCustomTimeZone (id, baseUtcOffset, displayName, standardDisplayName, null, null, true);
 375                 }
 376
 377                 public static TimeZoneInfo CreateCustomTimeZone (string id, TimeSpan baseUtcOffset, string displayName, string standardDisplayName, string daylightDisplayName, TimeZoneInfo.AdjustmentRule [] adjustmentRules)
 378                 {
 379                         return CreateCustomTimeZone (id, baseUtcOffset, displayName, standardDisplayName, daylightDisplayName, adjustmentRules, false);
 380                 }
 381
 382                 public static TimeZoneInfo CreateCustomTimeZone ( string id, TimeSpan baseUtcOffset, string displayName, string standardDisplayName, string daylightDisplayName, TimeZoneInfo.AdjustmentRule [] adjustmentRules, bool disableDaylightSavingTime)
 383                 {
 384                         return new TimeZoneInfo (id, baseUtcOffset, displayName, standardDisplayName, daylightDisplayName, adjustmentRules, disableDaylightSavingTime);
 385                 }
 386
 387 #if NET_4_5
 388                 public override bool Equals (object obj)
 389                 {
 390                         return Equals (obj as TimeZoneInfo);
 391                 }
 392 #endif
 393
 394                 public bool Equals (TimeZoneInfo other)
 395                 {
 396                         if (other == null)
 397                                 return false;
 398
 399                         return other.Id == this.Id && HasSameRules (other);
 400                 }
 401
 402                 public static TimeZoneInfo FindSystemTimeZoneById (string id)
 403                 {
 404                         //FIXME: this method should check for cached values in systemTimeZones
 405                         if (id == null)
 406                                 throw new ArgumentNullException ("id");
 407 #if !NET_2_1
 408                         if (TimeZoneKey != null)
 409                         {
 410                                 RegistryKey key = TimeZoneKey.OpenSubKey (id, false);
 411                                 if (key == null)
 412                                         throw new TimeZoneNotFoundException ();
 413                                 return FromRegistryKey(id, key);
 414                         }
 415 #endif
 416 #if MONODROID
 417                         var timeZoneInfo = AndroidTimeZones.GetTimeZone (id);
 418                         if (timeZoneInfo == null)
 419                                 throw new TimeZoneNotFoundException ();
 420                         return timeZoneInfo;
 421 #else
 422                         // Local requires special logic that already exists in the Local property (bug #326)
 423                         if (id == "Local")
 424                                 return Local;
 425 #if MONOTOUCH
 426                         using (Stream stream = GetMonoTouchData (id)) {
 427                                 return BuildFromStream (id, stream);
 428                         }
 429 #elif LIBC
 430                         string filepath = Path.Combine (TimeZoneDirectory, id);
 431                         return FindSystemTimeZoneByFileName (id, filepath);
 432 #else
 433                         throw new NotImplementedException ();
 434 #endif
 435 #endif
 436                 }
 437
 438 #if LIBC
 439                 private static TimeZoneInfo FindSystemTimeZoneByFileName (string id, string filepath)
 440                 {
 441                         if (!File.Exists (filepath))
 442                                 throw new TimeZoneNotFoundException ();
 443
 444                         using (FileStream stream = File.OpenRead (filepath)) {
 445                                 return BuildFromStream (id, stream);
 446                         }
 447                 }
 448 #endif
 449 #if LIBC || MONOTOUCH
 450                 const int BUFFER_SIZE = 16384; //Big enough for any tz file (on Oct 2008, all tz files are under 10k)
 451
 452                 private static TimeZoneInfo BuildFromStream (string id, Stream stream)
 453                 {
 454                         byte [] buffer = new byte [BUFFER_SIZE];
 455                         int length = stream.Read (buffer, 0, BUFFER_SIZE);
 456
 457                         if (!ValidTZFile (buffer, length))
 458                                 throw new InvalidTimeZoneException ("TZ file too big for the buffer");
 459
 460                         try {
 461                                 return ParseTZBuffer (id, buffer, length);
 462                         } catch (Exception e) {
 463                                 throw new InvalidTimeZoneException (e.Message);
 464                         }
 465                 }
 466 #endif
 467
 468 #if !NET_2_1
 469                 private static TimeZoneInfo FromRegistryKey (string id, RegistryKey key)
 470                 {
 471                         byte [] reg_tzi = (byte []) key.GetValue ("TZI");
 472
 473                         if (reg_tzi == null)
 474                                 throw new InvalidTimeZoneException ();
 475
 476                         int bias = BitConverter.ToInt32 (reg_tzi, 0);
 477                         TimeSpan baseUtcOffset = new TimeSpan (0, -bias, 0);
 478
 479                         string display_name = (string) key.GetValue ("Display");
 480                         string standard_name = (string) key.GetValue ("Std");
 481                         string daylight_name = (string) key.GetValue ("Dlt");
 482
 483                         List<AdjustmentRule> adjustmentRules = new List<AdjustmentRule> ();
 484
 485                         RegistryKey dst_key = key.OpenSubKey ("Dynamic DST", false);
 486                         if (dst_key != null) {
 487                                 int first_year = (int) dst_key.GetValue ("FirstEntry");
 488                                 int last_year = (int) dst_key.GetValue ("LastEntry");
 489                                 int year;
 490
 491                                 for (year=first_year; year<=last_year; year++) {
 492                                         byte [] dst_tzi = (byte []) dst_key.GetValue (year.ToString ());
 493                                         if (dst_tzi != null) {
 494                                                 int start_year = year == first_year ? 1 : year;
 495                                                 int end_year = year == last_year ? 9999 : year;
 496                                                 ParseRegTzi(adjustmentRules, start_year, end_year, dst_tzi);
 497                                         }
 498                                 }
 499                         }
 500                         else
 501                                 ParseRegTzi(adjustmentRules, 1, 9999, reg_tzi);
 502
 503                         return CreateCustomTimeZone (id, baseUtcOffset, display_name, standard_name, daylight_name, ValidateRules (adjustmentRules).ToArray ());
 504                 }
 505
 506                 private static void ParseRegTzi (List<AdjustmentRule> adjustmentRules, int start_year, int end_year, byte [] buffer)
 507                 {
 508                         //int standard_bias = BitConverter.ToInt32 (buffer, 4); /* not sure how to handle this */
 509                         int daylight_bias = BitConverter.ToInt32 (buffer, 8);
 510
 511                         int standard_year = BitConverter.ToInt16 (buffer, 12);
 512                         int standard_month = BitConverter.ToInt16 (buffer, 14);
 513                         int standard_dayofweek = BitConverter.ToInt16 (buffer, 16);
 514                         int standard_day = BitConverter.ToInt16 (buffer, 18);
 515                         int standard_hour = BitConverter.ToInt16 (buffer, 20);
 516                         int standard_minute = BitConverter.ToInt16 (buffer, 22);
 517                         int standard_second = BitConverter.ToInt16 (buffer, 24);
 518                         int standard_millisecond = BitConverter.ToInt16 (buffer, 26);
 519
 520                         int daylight_year = BitConverter.ToInt16 (buffer, 28);
 521                         int daylight_month = BitConverter.ToInt16 (buffer, 30);
 522                         int daylight_dayofweek = BitConverter.ToInt16 (buffer, 32);
 523                         int daylight_day = BitConverter.ToInt16 (buffer, 34);
 524                         int daylight_hour = BitConverter.ToInt16 (buffer, 36);
 525                         int daylight_minute = BitConverter.ToInt16 (buffer, 38);
 526                         int daylight_second = BitConverter.ToInt16 (buffer, 40);
 527                         int daylight_millisecond = BitConverter.ToInt16 (buffer, 42);
 528
 529                         if (standard_month == 0 || daylight_month == 0)
 530                                 return;
 531
 532                         DateTime start_date;
 533                         DateTime start_timeofday = new DateTime (1, 1, 1, daylight_hour, daylight_minute, daylight_second, daylight_millisecond);
 534                         TransitionTime start_transition_time;
 535
 536                         if (daylight_year == 0) {
 537                                 start_date = new DateTime (start_year, 1, 1);
 538                                 start_transition_time = TransitionTime.CreateFloatingDateRule (
 539                                         start_timeofday, daylight_month, daylight_day,
 540                                         (DayOfWeek) daylight_dayofweek);
 541                         }
 542                         else {
 543                                 start_date = new DateTime (daylight_year, daylight_month, daylight_day,
 544                                         daylight_hour, daylight_minute, daylight_second, daylight_millisecond);
 545                                 start_transition_time = TransitionTime.CreateFixedDateRule (
 546                                         start_timeofday, daylight_month, daylight_day);
 547                         }
 548
 549                         DateTime end_date;
 550                         DateTime end_timeofday = new DateTime (1, 1, 1, standard_hour, standard_minute, standard_second, standard_millisecond);
 551                         TransitionTime end_transition_time;
 552
 553                         if (standard_year == 0) {
 554                                 end_date = new DateTime (end_year, 12, 31);
 555                                 end_transition_time = TransitionTime.CreateFloatingDateRule (
 556                                         end_timeofday, standard_month, standard_day,
 557                                         (DayOfWeek) standard_dayofweek);
 558                         }
 559                         else {
 560                                 end_date = new DateTime (standard_year, standard_month, standard_day,
 561                                         standard_hour, standard_minute, standard_second, standard_millisecond);
 562                                 end_transition_time = TransitionTime.CreateFixedDateRule (
 563                                         end_timeofday, standard_month, standard_day);
 564                         }
 565
 566                         TimeSpan daylight_delta = new TimeSpan(0, -daylight_bias, 0);
 567
 568                         adjustmentRules.Add (AdjustmentRule.CreateAdjustmentRule (
 569                                 start_date, end_date, daylight_delta,
 570                                 start_transition_time, end_transition_time));
 571                 }
 572 #endif
 573
 574                 public static TimeZoneInfo FromSerializedString (string source)
 575                 {
 576                         throw new NotImplementedException ();
 577                 }
 578
 579                 public AdjustmentRule [] GetAdjustmentRules ()
 580                 {
 581                         if (!supportsDaylightSavingTime)
 582                                 return new AdjustmentRule [0];
 583                         else
 584                                 return (AdjustmentRule []) adjustmentRules.Clone ();
 585                 }
 586
 587                 public TimeSpan [] GetAmbiguousTimeOffsets (DateTime dateTime)
 588                 {
 589                         if (!IsAmbiguousTime (dateTime))
 590                                 throw new ArgumentException ("dateTime is not an ambiguous time");
 591
 592                         AdjustmentRule rule = GetApplicableRule (dateTime);
 593                         if (rule != null)
 594                                 return new TimeSpan[] {baseUtcOffset, baseUtcOffset + rule.DaylightDelta};
 595                         else
 596                                 return new TimeSpan[] {baseUtcOffset, baseUtcOffset};
 597                 }
 598
 599                 public TimeSpan [] GetAmbiguousTimeOffsets (DateTimeOffset dateTimeOffset)
 600                 {
 601                         if (!IsAmbiguousTime (dateTimeOffset))
 602                                 throw new ArgumentException ("dateTimeOffset is not an ambiguous time");
 603
 604                         throw new NotImplementedException ();
 605                 }
 606
 607                 public override int GetHashCode ()
 608                 {
 609                         int hash_code = Id.GetHashCode ();
 610                         foreach (AdjustmentRule rule in GetAdjustmentRules ())
 611                                 hash_code ^= rule.GetHashCode ();
 612                         return hash_code;
 613                 }
 614
 615 #if NET_4_0
 616                 void ISerializable.GetObjectData (SerializationInfo info, StreamingContext context)
 617 #else
 618                 public void GetObjectData (SerializationInfo info, StreamingContext context)
 619 #endif
 620                 {
 621                         if (info == null)
 622                                 throw new ArgumentNullException ("info");
 623                         info.AddValue ("Id", id);
 624                         info.AddValue ("DisplayName", displayName);
 625                         info.AddValue ("StandardName", standardDisplayName);
 626                         info.AddValue ("DaylightName", daylightDisplayName);
 627                         info.AddValue ("BaseUtcOffset", baseUtcOffset);
 628                         info.AddValue ("AdjustmentRules", adjustmentRules);
 629                         info.AddValue ("SupportsDaylightSavingTime", SupportsDaylightSavingTime);
 630                 }
 631
 632                 //FIXME: change this to a generic Dictionary and allow caching for FindSystemTimeZoneById
 633                 private static List<TimeZoneInfo> systemTimeZones;
 634                 public static ReadOnlyCollection<TimeZoneInfo> GetSystemTimeZones ()
 635                 {
 636                         if (systemTimeZones == null) {
 637                                 systemTimeZones = new List<TimeZoneInfo> ();
 638 #if !NET_2_1
 639                                 if (TimeZoneKey != null) {
 640                                         foreach (string id in TimeZoneKey.GetSubKeyNames ()) {
 641                                                 try {
 642                                                         systemTimeZones.Add (FindSystemTimeZoneById (id));
 643                                                 } catch {}
 644                                         }
 645
 646                                         return new ReadOnlyCollection<TimeZoneInfo> (systemTimeZones);
 647                                 }
 648 #endif
 649 #if MONODROID
 650                         foreach (string id in AndroidTimeZones.GetAvailableIds ()) {
 651                                 var tz = AndroidTimeZones.GetTimeZone (id);
 652                                 if (tz != null)
 653                                         systemTimeZones.Add (tz);
 654                         }
 655 #elif MONOTOUCH
 656                                 if (systemTimeZones.Count == 0) {
 657                                         foreach (string name in GetMonoTouchNames ()) {
 658                                                 using (Stream stream = GetMonoTouchData (name)) {
 659                                                         systemTimeZones.Add (BuildFromStream (name, stream));
 660                                                 }
 661                                         }
 662                                 }
 663 #elif LIBC
 664                                 string[] continents = new string [] {"Africa", "America", "Antarctica", "Arctic", "Asia", "Atlantic", "Brazil", "Canada", "Chile", "Europe", "Indian", "Mexico", "Mideast", "Pacific", "US"};
 665                                 foreach (string continent in continents) {
 666                                         try {
 667                                                 foreach (string zonepath in Directory.GetFiles (Path.Combine (TimeZoneDirectory, continent))) {
 668                                                         try {
 669                                                                 string id = String.Format ("{0}/{1}", continent, Path.GetFileName (zonepath));
 670                                                                 systemTimeZones.Add (FindSystemTimeZoneById (id));
 671                                                         } catch (ArgumentNullException) {
 672                                                         } catch (TimeZoneNotFoundException) {
 673                                                         } catch (InvalidTimeZoneException) {
 674                                                         } catch (Exception) {
 675                                                                 throw;
 676                                                         }
 677                                                 }
 678                                         } catch {}
 679                                 }
 680 #else
 681                                 throw new NotImplementedException ("This method is not implemented for this platform");
 682 #endif
 683                         }
 684                         return new ReadOnlyCollection<TimeZoneInfo> (systemTimeZones);
 685                 }
 686
 687                 public TimeSpan GetUtcOffset (DateTime dateTime)
 688                 {
 689                         if (IsDaylightSavingTime (dateTime)) {
 690                                 AdjustmentRule rule = GetApplicableRule (dateTime);
 691                                 if (rule != null)
 692                                         return BaseUtcOffset + rule.DaylightDelta;
 693                         }
 694
 695                         return BaseUtcOffset;
 696                 }
 697
 698                 public TimeSpan GetUtcOffset (DateTimeOffset dateTimeOffset)
 699                 {
 700                         throw new NotImplementedException ();
 701                 }
 702
 703                 public bool HasSameRules (TimeZoneInfo other)
 704                 {
 705                         if (other == null)
 706                                 throw new ArgumentNullException ("other");
 707
 708                         if ((this.adjustmentRules == null) != (other.adjustmentRules == null))
 709                                 return false;
 710
 711                         if (this.adjustmentRules == null)
 712                                 return true;
 713
 714                         if (this.BaseUtcOffset != other.BaseUtcOffset)
 715                                 return false;
 716
 717                         if (this.adjustmentRules.Length != other.adjustmentRules.Length)
 718                                 return false;
 719
 720                         for (int i = 0; i < adjustmentRules.Length; i++) {
 721                                 if (! (this.adjustmentRules [i]).Equals (other.adjustmentRules [i]))
 722                                         return false;
 723                         }
 724
 725                         return true;
 726                 }
 727
 728                 public bool IsAmbiguousTime (DateTime dateTime)
 729                 {
 730                         if (dateTime.Kind == DateTimeKind.Local && IsInvalidTime (dateTime))
 731                                 throw new ArgumentException ("Kind is Local and time is Invalid");
 732
 733                         if (this == TimeZoneInfo.Utc)
 734                                 return false;
 735
 736                         if (dateTime.Kind == DateTimeKind.Utc)
 737                                 dateTime = ConvertTimeFromUtc (dateTime);
 738
 739                         if (dateTime.Kind == DateTimeKind.Local && this != TimeZoneInfo.Local)
 740                                 dateTime = ConvertTime (dateTime, TimeZoneInfo.Local, this);
 741
 742                         AdjustmentRule rule = GetApplicableRule (dateTime);
 743                         if (rule != null) {
 744                                 DateTime tpoint = TransitionPoint (rule.DaylightTransitionEnd, dateTime.Year);
 745                                 if (dateTime > tpoint - rule.DaylightDelta  && dateTime <= tpoint)
 746                                         return true;
 747                         }
 748
 749                         return false;
 750                 }
 751
 752                 public bool IsAmbiguousTime (DateTimeOffset dateTimeOffset)
 753                 {
 754                         throw new NotImplementedException ();
 755                 }
 756
 757                 public bool IsDaylightSavingTime (DateTime dateTime)
 758                 {
 759                         if (dateTime.Kind == DateTimeKind.Local && IsInvalidTime (dateTime))
 760                                 throw new ArgumentException ("dateTime is invalid and Kind is Local");
 761
 762                         if (this == TimeZoneInfo.Utc)
 763                                 return false;
 764
 765                         if (!SupportsDaylightSavingTime)
 766                                 return false;
 767                         //FIXME: do not rely on DateTime implementation !
 768                         if ((dateTime.Kind == DateTimeKind.Local || dateTime.Kind == DateTimeKind.Unspecified) && this == TimeZoneInfo.Local)
 769                                 return dateTime.IsDaylightSavingTime ();
 770
 771                         //FIXME: do not rely on DateTime implementation !
 772                         if (dateTime.Kind == DateTimeKind.Local && this != TimeZoneInfo.Utc)
 773                                 return IsDaylightSavingTime (DateTime.SpecifyKind (dateTime.ToUniversalTime (), DateTimeKind.Utc));
 774
 775                         AdjustmentRule rule = GetApplicableRule (dateTime.Date);
 776                         if (rule == null)
 777                                 return false;
 778
 779                         DateTime DST_start = TransitionPoint (rule.DaylightTransitionStart, dateTime.Year);
 780                         DateTime DST_end = TransitionPoint (rule.DaylightTransitionEnd, dateTime.Year + ((rule.DaylightTransitionStart.Month < rule.DaylightTransitionEnd.Month) ? 0 : 1));
 781                         if (dateTime.Kind == DateTimeKind.Utc) {
 782                                 DST_start -= BaseUtcOffset;
 783                                 DST_end -= (BaseUtcOffset + rule.DaylightDelta);
 784                         }
 785
 786                         return (dateTime >= DST_start && dateTime < DST_end);
 787                 }
 788
 789                 public bool IsDaylightSavingTime (DateTimeOffset dateTimeOffset)
 790                 {
 791                         throw new NotImplementedException ();
 792                 }
 793
 794                 public bool IsInvalidTime (DateTime dateTime)
 795                 {
 796                         if (dateTime.Kind == DateTimeKind.Utc)
 797                                 return false;
 798                         if (dateTime.Kind == DateTimeKind.Local && this != Local)
 799                                 return false;
 800
 801                         AdjustmentRule rule = GetApplicableRule (dateTime);
 802                         if (rule != null) {
 803                                 DateTime tpoint = TransitionPoint (rule.DaylightTransitionStart, dateTime.Year);
 804                                 if (dateTime >= tpoint && dateTime < tpoint + rule.DaylightDelta)
 805                                         return true;
 806                         }
 807
 808                         return false;
 809                 }
 810
 811 #if NET_4_0
 812                 void IDeserializationCallback.OnDeserialization (object sender)
 813 #else
 814                 public void OnDeserialization (object sender)
 815 #endif
 816                 {
 817                         try {
 818                                         TimeZoneInfo.Validate (id, baseUtcOffset, adjustmentRules);
 819                                 } catch (ArgumentException ex) {
 820                                         throw new SerializationException ("invalid serialization data", ex);
 821                                 }
 822                 }
 823
 824                 private static void Validate (string id, TimeSpan baseUtcOffset, AdjustmentRule [] adjustmentRules)
 825                 {
 826                         if (id == null)
 827                                 throw new ArgumentNullException ("id");
 828
 829                         if (id == String.Empty)
 830                                 throw new ArgumentException ("id parameter is an empty string");
 831
 832                         if (baseUtcOffset.Ticks % TimeSpan.TicksPerMinute != 0)
 833                                 throw new ArgumentException ("baseUtcOffset parameter does not represent a whole number of minutes");
 834
 835                         if (baseUtcOffset > new TimeSpan (14, 0, 0) || baseUtcOffset < new TimeSpan (-14, 0, 0))
 836                                 throw new ArgumentOutOfRangeException ("baseUtcOffset parameter is greater than 14 hours or less than -14 hours");
 837
 838 #if STRICT
 839                         if (id.Length > 32)
 840                                 throw new ArgumentException ("id parameter shouldn't be longer than 32 characters");
 841 #endif
 842
 843                         if (adjustmentRules != null && adjustmentRules.Length != 0) {
 844                                 AdjustmentRule prev = null;
 845                                 foreach (AdjustmentRule current in adjustmentRules) {
 846                                         if (current == null)
 847                                                 throw new InvalidTimeZoneException ("one or more elements in adjustmentRules are null");
 848
 849                                         if ((baseUtcOffset + current.DaylightDelta < new TimeSpan (-14, 0, 0)) ||
 850                                                         (baseUtcOffset + current.DaylightDelta > new TimeSpan (14, 0, 0)))
 851                                                 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;");
 852
 853                                         if (prev != null && prev.DateStart > current.DateStart)
 854                                                 throw new InvalidTimeZoneException ("adjustment rules specified in adjustmentRules parameter are not in chronological order");
 855
 856                                         if (prev != null && prev.DateEnd > current.DateStart)
 857                                                 throw new InvalidTimeZoneException ("some adjustment rules in the adjustmentRules parameter overlap");
 858
 859                                         if (prev != null && prev.DateEnd == current.DateStart)
 860                                                 throw new InvalidTimeZoneException ("a date can have multiple adjustment rules applied to it");
 861
 862                                         prev = current;
 863                                 }
 864                         }
 865                 }
 866
 867                 public string ToSerializedString ()
 868                 {
 869                         throw new NotImplementedException ();
 870                 }
 871
 872                 public override string ToString ()
 873                 {
 874                         return DisplayName;
 875                 }
 876
 877                 private TimeZoneInfo (SerializationInfo info, StreamingContext context)
 878                 {
 879                         if (info == null)
 880                                 throw new ArgumentNullException ("info");
 881                         id = (string) info.GetValue ("Id", typeof (string));
 882                         displayName = (string) info.GetValue ("DisplayName", typeof (string));
 883                         standardDisplayName = (string) info.GetValue ("StandardName", typeof (string));
 884                         daylightDisplayName = (string) info.GetValue ("DaylightName", typeof (string));
 885                         baseUtcOffset = (TimeSpan) info.GetValue ("BaseUtcOffset", typeof (TimeSpan));
 886                         adjustmentRules = (TimeZoneInfo.AdjustmentRule []) info.GetValue ("AdjustmentRules", typeof (TimeZoneInfo.AdjustmentRule []));
 887                         supportsDaylightSavingTime = (bool) info.GetValue ("SupportsDaylightSavingTime", typeof (bool));
 888                 }
 889
 890                 private TimeZoneInfo (string id, TimeSpan baseUtcOffset, string displayName, string standardDisplayName, string daylightDisplayName, TimeZoneInfo.AdjustmentRule [] adjustmentRules, bool disableDaylightSavingTime)
 891                 {
 892                         if (id == null)
 893                                 throw new ArgumentNullException ("id");
 894
 895                         if (id == String.Empty)
 896                                 throw new ArgumentException ("id parameter is an empty string");
 897
 898                         if (baseUtcOffset.Ticks % TimeSpan.TicksPerMinute != 0)
 899                                 throw new ArgumentException ("baseUtcOffset parameter does not represent a whole number of minutes");
 900
 901                         if (baseUtcOffset > new TimeSpan (14, 0, 0) || baseUtcOffset < new TimeSpan (-14, 0, 0))
 902                                 throw new ArgumentOutOfRangeException ("baseUtcOffset parameter is greater than 14 hours or less than -14 hours");
 903
 904 #if STRICT
 905                         if (id.Length > 32)
 906                                 throw new ArgumentException ("id parameter shouldn't be longer than 32 characters");
 907 #endif
 908
 909                         bool supportsDaylightSavingTime = !disableDaylightSavingTime;
 910
 911                         if (adjustmentRules != null && adjustmentRules.Length != 0) {
 912                                 AdjustmentRule prev = null;
 913                                 foreach (AdjustmentRule current in adjustmentRules) {
 914                                         if (current == null)
 915                                                 throw new InvalidTimeZoneException ("one or more elements in adjustmentRules are null");
 916
 917                                         if ((baseUtcOffset + current.DaylightDelta < new TimeSpan (-14, 0, 0)) ||
 918                                                         (baseUtcOffset + current.DaylightDelta > new TimeSpan (14, 0, 0)))
 919                                                 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;");
 920
 921                                         if (prev != null && prev.DateStart > current.DateStart)
 922                                                 throw new InvalidTimeZoneException ("adjustment rules specified in adjustmentRules parameter are not in chronological order");
 923
 924                                         if (prev != null && prev.DateEnd > current.DateStart)
 925                                                 throw new InvalidTimeZoneException ("some adjustment rules in the adjustmentRules parameter overlap");
 926
 927                                         if (prev != null && prev.DateEnd == current.DateStart)
 928                                                 throw new InvalidTimeZoneException ("a date can have multiple adjustment rules applied to it");
 929
 930                                         prev = current;
 931                                 }
 932                         } else {
 933                                 supportsDaylightSavingTime = false;
 934                         }
 935
 936                         this.id = id;
 937                         this.baseUtcOffset = baseUtcOffset;
 938                         this.displayName = displayName ?? id;
 939                         this.standardDisplayName = standardDisplayName ?? id;
 940                         this.daylightDisplayName = daylightDisplayName;
 941                         this.supportsDaylightSavingTime = supportsDaylightSavingTime;
 942                         this.adjustmentRules = adjustmentRules;
 943                 }
 944
 945                 private AdjustmentRule GetApplicableRule (DateTime dateTime)
 946                 {
 947                         //Transitions are always in standard time
 948                         DateTime date = dateTime;
 949
 950                         if (dateTime.Kind == DateTimeKind.Local && this != TimeZoneInfo.Local)
 951                                 date = date.ToUniversalTime () + BaseUtcOffset;
 952
 953                         if (dateTime.Kind == DateTimeKind.Utc && this != TimeZoneInfo.Utc)
 954                                 date = date + BaseUtcOffset;
 955
 956                         if (adjustmentRules != null) {
 957                                 foreach (AdjustmentRule rule in adjustmentRules) {
 958                                         if (rule.DateStart > date.Date)
 959                                                 return null;
 960                                         if (rule.DateEnd < date.Date)
 961                                                 continue;
 962                                         return rule;
 963                                 }
 964                         }
 965                         return null;
 966                 }
 967
 968                 private static DateTime TransitionPoint (TransitionTime transition, int year)
 969                 {
 970                         if (transition.IsFixedDateRule)
 971                                 return new DateTime (year, transition.Month, transition.Day) + transition.TimeOfDay.TimeOfDay;
 972
 973                         DayOfWeek first = (new DateTime (year, transition.Month, 1)).DayOfWeek;
 974                         int day = 1 + (transition.Week - 1) * 7 + (transition.DayOfWeek - first) % 7;
 975                         if (day >  DateTime.DaysInMonth (year, transition.Month))
 976                                 day -= 7;
 977                         return new DateTime (year, transition.Month, day) + transition.TimeOfDay.TimeOfDay;
 978                 }
 979
 980                 static List<AdjustmentRule> ValidateRules (List<AdjustmentRule> adjustmentRules)
 981                 {
 982                         AdjustmentRule prev = null;
 983                         foreach (AdjustmentRule current in adjustmentRules.ToArray ()) {
 984                                 if (prev != null && prev.DateEnd > current.DateStart) {
 985                                         adjustmentRules.Remove (current);
 986                                 }
 987                                 prev = current;
 988                         }
 989                         return adjustmentRules;
 990                 }
 991
 992 #if LIBC || MONODROID
 993                 private static bool ValidTZFile (byte [] buffer, int length)
 994                 {
 995                         StringBuilder magic = new StringBuilder ();
 996
 997                         for (int i = 0; i < 4; i++)
 998                                 magic.Append ((char)buffer [i]);
 999
1000                         if (magic.ToString () != "TZif")
1001                                 return false;
1002
1003                         if (length >= BUFFER_SIZE)
1004                                 return false;
1005
1006                         return true;
1007                 }
1008
1009                 static int SwapInt32 (int i)
1010                 {
1011                         return (((i >> 24) & 0xff)
1012                                 | ((i >> 8) & 0xff00)
1013                                 | ((i << 8) & 0xff0000)
1014                                 | ((i << 24)));
1015                 }
1016
1017                 static int ReadBigEndianInt32 (byte [] buffer, int start)
1018                 {
1019                         int i = BitConverter.ToInt32 (buffer, start);
1020                         if (!BitConverter.IsLittleEndian)
1021                                 return i;
1022
1023                         return SwapInt32 (i);
1024                 }
1025
1026                 private static TimeZoneInfo ParseTZBuffer (string id, byte [] buffer, int length)
1027                 {
1028                         //Reading the header. 4 bytes for magic, 16 are reserved
1029                         int ttisgmtcnt = ReadBigEndianInt32 (buffer, 20);
1030                         int ttisstdcnt = ReadBigEndianInt32 (buffer, 24);
1031                         int leapcnt = ReadBigEndianInt32 (buffer, 28);
1032                         int timecnt = ReadBigEndianInt32 (buffer, 32);
1033                         int typecnt = ReadBigEndianInt32 (buffer, 36);
1034                         int charcnt = ReadBigEndianInt32 (buffer, 40);
1035
1036                         if (length < 44 + timecnt * 5 + typecnt * 6 + charcnt + leapcnt * 8 + ttisstdcnt + ttisgmtcnt)
1037                                 throw new InvalidTimeZoneException ();
1038
1039                         Dictionary<int, string> abbreviations = ParseAbbreviations (buffer, 44 + 4 * timecnt + timecnt + 6 * typecnt, charcnt);
1040                         Dictionary<int, TimeType> time_types = ParseTimesTypes (buffer, 44 + 4 * timecnt + timecnt, typecnt, abbreviations);
1041                         List<KeyValuePair<DateTime, TimeType>> transitions = ParseTransitions (buffer, 44, timecnt, time_types);
1042
1043                         if (time_types.Count == 0)
1044                                 throw new InvalidTimeZoneException ();
1045
1046                         if (time_types.Count == 1 && ((TimeType)time_types[0]).IsDst)
1047                                 throw new InvalidTimeZoneException ();
1048
1049                         TimeSpan baseUtcOffset = new TimeSpan (0);
1050                         TimeSpan dstDelta = new TimeSpan (0);
1051                         string standardDisplayName = null;
1052                         string daylightDisplayName = null;
1053                         bool dst_observed = false;
1054                         DateTime dst_start = DateTime.MinValue;
1055                         List<AdjustmentRule> adjustmentRules = new List<AdjustmentRule> ();
1056
1057                         for (int i = 0; i < transitions.Count; i++) {
1058                                 var pair = transitions [i];
1059                                 DateTime ttime = pair.Key;
1060                                 TimeType ttype = pair.Value;
1061                                 if (!ttype.IsDst) {
1062                                         if (standardDisplayName != ttype.Name || baseUtcOffset.TotalSeconds != ttype.Offset) {
1063                                                 standardDisplayName = ttype.Name;
1064                                                 daylightDisplayName = null;
1065                                                 baseUtcOffset = new TimeSpan (0, 0, ttype.Offset);
1066                                                 adjustmentRules = new List<AdjustmentRule> ();
1067                                                 dst_observed = false;
1068                                         }
1069                                         if (dst_observed) {
1070                                                 //FIXME: check additional fields for this:
1071                                                 //most of the transitions are expressed in GMT
1072                                                 dst_start += baseUtcOffset;
1073                                                 DateTime dst_end = ttime + baseUtcOffset + dstDelta;
1074
1075                                                 //some weird timezone (America/Phoenix) have end dates on Jan 1st
1076                                                 if (dst_end.Date == new DateTime (dst_end.Year, 1, 1) && dst_end.Year > dst_start.Year)
1077                                                         dst_end -= new TimeSpan (24, 0, 0);
1078
1079                                                 DateTime dateStart, dateEnd;
1080                                                 if (dst_start.Month < 7)
1081                                                         dateStart = new DateTime (dst_start.Year, 1, 1);
1082                                                 else
1083                                                         dateStart = new DateTime (dst_start.Year, 7, 1);
1084
1085                                                 if (dst_end.Month >= 7)
1086                                                         dateEnd = new DateTime (dst_end.Year, 12, 31);
1087                                                 else
1088                                                         dateEnd = new DateTime (dst_end.Year, 6, 30);
1089
1090
1091                                                 TransitionTime transition_start = TransitionTime.CreateFixedDateRule (new DateTime (1, 1, 1) + dst_start.TimeOfDay, dst_start.Month, dst_start.Day);
1092                                                 TransitionTime transition_end = TransitionTime.CreateFixedDateRule (new DateTime (1, 1, 1) + dst_end.TimeOfDay, dst_end.Month, dst_end.Day);
1093                                                 if  (transition_start != transition_end) //y, that happened in Argentina in 1943-1946
1094                                                         adjustmentRules.Add (AdjustmentRule.CreateAdjustmentRule (dateStart, dateEnd, dstDelta, transition_start, transition_end));
1095                                         }
1096                                         dst_observed = false;
1097                                 } else {
1098                                         if (daylightDisplayName != ttype.Name || dstDelta.TotalSeconds != ttype.Offset - baseUtcOffset.TotalSeconds) {
1099                                                 daylightDisplayName = ttype.Name;
1100                                                 dstDelta = new TimeSpan(0, 0, ttype.Offset) - baseUtcOffset;
1101                                         }
1102                                         dst_start = ttime;
1103                                         dst_observed = true;
1104                                 }
1105                         }
1106
1107                         if (adjustmentRules.Count == 0) {
1108                                 TimeType t = (TimeType)time_types [0];
1109                                 if (standardDisplayName == null) {
1110                                         standardDisplayName = t.Name;
1111                                         baseUtcOffset = new TimeSpan (0, 0, t.Offset);
1112                                 }
1113                                 return CreateCustomTimeZone (id, baseUtcOffset, id, standardDisplayName);
1114                         } else {
1115                                 return CreateCustomTimeZone (id, baseUtcOffset, id, standardDisplayName, daylightDisplayName, ValidateRules (adjustmentRules).ToArray ());
1116                         }
1117                 }
1118
1119                 static Dictionary<int, string> ParseAbbreviations (byte [] buffer, int index, int count)
1120                 {
1121                         var abbrevs = new Dictionary<int, string> ();
1122                         int abbrev_index = 0;
1123                         var sb = new StringBuilder ();
1124                         for (int i = 0; i < count; i++) {
1125                                 char c = (char) buffer [index + i];
1126                                 if (c != '\0')
1127                                         sb.Append (c);
1128                                 else {
1129                                         abbrevs.Add (abbrev_index, sb.ToString ());
1130                                         //Adding all the substrings too, as it seems to be used, at least for Africa/Windhoek
1131                                         for (int j = 1; j < sb.Length; j++)
1132                                                 abbrevs.Add (abbrev_index + j, sb.ToString (j, sb.Length - j));
1133                                         abbrev_index = i + 1;
1134                                         sb = new StringBuilder ();
1135                                 }
1136                         }
1137                         return abbrevs;
1138                 }
1139
1140                 static Dictionary<int, TimeType> ParseTimesTypes (byte [] buffer, int index, int count, Dictionary<int, string> abbreviations)
1141                 {
1142                         var types = new Dictionary<int, TimeType> (count);
1143                         for (int i = 0; i < count; i++) {
1144                                 int offset = ReadBigEndianInt32 (buffer, index + 6 * i);
1145                                 byte is_dst = buffer [index + 6 * i + 4];
1146                                 byte abbrev = buffer [index + 6 * i + 5];
1147                                 types.Add (i, new TimeType (offset, (is_dst != 0), abbreviations [(int)abbrev]));
1148                         }
1149                         return types;
1150                 }
1151
1152                 static List<KeyValuePair<DateTime, TimeType>> ParseTransitions (byte [] buffer, int index, int count, Dictionary<int, TimeType> time_types)
1153                 {
1154                         var list = new List<KeyValuePair<DateTime, TimeType>> (count);
1155                         for (int i = 0; i < count; i++) {
1156                                 int unixtime = ReadBigEndianInt32 (buffer, index + 4 * i);
1157                                 DateTime ttime = DateTimeFromUnixTime (unixtime);
1158                                 byte ttype = buffer [index + 4 * count + i];
1159                                 list.Add (new KeyValuePair<DateTime, TimeType> (ttime, time_types [(int)ttype]));
1160                         }
1161                         return list;
1162                 }
1163
1164                 static DateTime DateTimeFromUnixTime (long unix_time)
1165                 {
1166                         DateTime date_time = new DateTime (1970, 1, 1);
1167                         return date_time.AddSeconds (unix_time);
1168                 }
1169         }
1170
1171         struct TimeType {
1172                 public readonly int Offset;
1173                 public readonly bool IsDst;
1174                 public string Name;
1175
1176                 public TimeType (int offset, bool is_dst, string abbrev)
1177                 {
1178                         this.Offset = offset;
1179                         this.IsDst = is_dst;
1180                         this.Name = abbrev;
1181                 }
1182
1183                 public override string ToString ()
1184                 {
1185                         return "offset: " + Offset + "s, is_dst: " + IsDst + ", zone name: " + Name;
1186                 }
1187 #else
1188         }
1189 #endif
1190         }
1191 }
1192
1193 #endif