mcs/class/corlib/System/TimeZoneInfo.Android.cs

   1 /*
   2  * System.TimeZoneInfo Android Support
   3  *
   4  * Author(s)
   5  *      Jonathan Pryor  <jpryor@novell.com>
   6  *      The Android Open Source Project
   7  *
   8  * Licensed under the Apache License, Version 2.0 (the "License");
   9  * you may not use this file except in compliance with the License.
  10  * You may obtain a copy of the License at
  11  *
  12  *      http://www.apache.org/licenses/LICENSE-2.0
  13  *
  14  * Unless required by applicable law or agreed to in writing, software
  15  * distributed under the License is distributed on an "AS IS" BASIS,
  16  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  17  * See the License for the specific language governing permissions and
  18  * limitations under the License.
  19  */
  20
  21 #if MONODROID
  22
  23 using System;
  24 using System.Collections.Generic;
  25 using System.IO;
  26 using System.Runtime.CompilerServices;
  27 using System.Runtime.InteropServices;
  28 using System.Text;
  29
  30 namespace System {
  31
  32         interface IAndroidTimeZoneDB {
  33                 IEnumerable<string>   GetAvailableIds ();
  34                 byte[]                GetTimeZoneData (string id);
  35         }
  36
  37         [StructLayout (LayoutKind.Sequential, Pack=1)]
  38         unsafe struct AndroidTzDataHeader {
  39                 public fixed byte signature [12];
  40                 public int        indexOffset;
  41                 public int        dataOffset;
  42                 public int        zoneTabOffset;
  43         }
  44
  45         [StructLayout (LayoutKind.Sequential, Pack=1)]
  46         unsafe struct AndroidTzDataEntry {
  47                 public fixed byte id [40];
  48                 public int        byteOffset;
  49                 public int        length;
  50                 public int        rawUtcOffset;
  51         }
  52
  53         /*
  54          * Android v4.3 Timezone support infrastructure.
  55          *
  56          * This is a C# port of libcore.util.ZoneInfoDB:
  57          *
  58          *    https://android.googlesource.com/platform/libcore/+/master/luni/src/main/java/libcore/util/ZoneInfoDB.java
  59          *
  60          * This is needed in order to read Android v4.3 tzdata files.
  61          */
  62         sealed class AndroidTzData : IAndroidTimeZoneDB {
  63
  64                 internal static readonly string[] Paths = new string[]{
  65                         Environment.GetEnvironmentVariable ("ANDROID_DATA") + "/misc/zoneinfo/tzdata",
  66                         Environment.GetEnvironmentVariable ("ANDROID_ROOT") + "/usr/share/zoneinfo/tzdata",
  67                 };
  68
  69                 string    tzdataPath;
  70                 Stream    data;
  71                 string    version;
  72                 string    zoneTab;
  73
  74                 string[]  ids;
  75                 int[]     byteOffsets;
  76                 int[]     lengths;
  77
  78                 public AndroidTzData (params string[] paths)
  79                 {
  80                         foreach (var path in paths)
  81                                 if (LoadData (path)) {
  82                                         tzdataPath = path;
  83                                         return;
  84                                 }
  85
  86                         Console.Error.WriteLine ("Couldn't find any tzdata!");
  87                         tzdataPath  = "/";
  88                         version     = "missing";
  89                         zoneTab     = "# Emergency fallback data.\n";
  90                         ids         = new[]{ "GMT" };
  91                 }
  92
  93                 public string Version {
  94                         get {return version;}
  95                 }
  96
  97                 public string ZoneTab {
  98                         get {return zoneTab;}
  99                 }
 100
 101                 bool LoadData (string path)
 102                 {
 103                         if (!File.Exists (path))
 104                                 return false;
 105                         try {
 106                                 data = File.OpenRead (path);
 107                         } catch (IOException) {
 108                                 return false;
 109                         } catch (UnauthorizedAccessException) {
 110                                 return false;
 111                         }
 112
 113                         try {
 114                                 ReadHeader ();
 115                                 return true;
 116                         } catch (Exception e) {
 117                                 Console.Error.WriteLine ("tzdata file \"{0}\" was present but invalid: {1}", path, e);
 118                         }
 119                         return false;
 120                 }
 121
 122                 unsafe void ReadHeader ()
 123                 {
 124                         int size   = System.Math.Max (Marshal.SizeOf (typeof (AndroidTzDataHeader)), Marshal.SizeOf (typeof (AndroidTzDataEntry)));
 125                         var buffer = new byte [size];
 126                         var header = ReadAt<AndroidTzDataHeader>(0, buffer);
 127
 128                         header.indexOffset    = NetworkToHostOrder (header.indexOffset);
 129                         header.dataOffset     = NetworkToHostOrder (header.dataOffset);
 130                         header.zoneTabOffset  = NetworkToHostOrder (header.zoneTabOffset);
 131
 132                         sbyte* s = (sbyte*) header.signature;
 133                         string magic = new string (s, 0, 6, Encoding.ASCII);
 134                         if (magic != "tzdata" || header.signature [11] != 0) {
 135                                 var b = new StringBuilder ();
 136                                 b.Append ("bad tzdata magic:");
 137                                 for (int i = 0; i < 12; ++i) {
 138                                         b.Append (" ").Append (((byte) s [i]).ToString ("x2"));
 139                                 }
 140                                 throw new InvalidOperationException ("bad tzdata magic: " + b.ToString ());
 141                         }
 142
 143                         version = new string (s, 6, 5, Encoding.ASCII);
 144
 145                         ReadIndex (header.indexOffset, header.dataOffset, buffer);
 146                         ReadZoneTab (header.zoneTabOffset, checked ((int) data.Length) - header.zoneTabOffset);
 147                 }
 148
 149                 unsafe T ReadAt<T> (long position, byte[] buffer)
 150                         where T : struct
 151                 {
 152                         int size = Marshal.SizeOf (typeof (T));
 153                         if (buffer.Length < size)
 154                                 throw new InvalidOperationException ("Internal error: buffer too small");
 155
 156                         data.Position = position;
 157                         int r;
 158                         if ((r = data.Read (buffer, 0, size)) < size)
 159                                 throw new InvalidOperationException (
 160                                                 string.Format ("Error reading '{0}': read {1} bytes, expected {2}", tzdataPath, r, size));
 161
 162                         fixed (byte* b = buffer)
 163                                 return (T) Marshal.PtrToStructure ((IntPtr) b, typeof (T));
 164                 }
 165
 166                 static int NetworkToHostOrder (int value)
 167                 {
 168                         if (!BitConverter.IsLittleEndian)
 169                                 return value;
 170
 171                         return
 172                                 (((value >> 24) & 0xFF) |
 173                                  ((value >> 08) & 0xFF00) |
 174                                  ((value << 08) & 0xFF0000) |
 175                                  ((value << 24)));
 176                 }
 177
 178                 unsafe void ReadIndex (int indexOffset, int dataOffset, byte[] buffer)
 179                 {
 180                         int indexSize   = dataOffset - indexOffset;
 181                         int entryCount  = indexSize / Marshal.SizeOf (typeof (AndroidTzDataEntry));
 182                         int entrySize   = Marshal.SizeOf (typeof (AndroidTzDataEntry));
 183
 184                         byteOffsets   = new int [entryCount];
 185                         ids           = new string [entryCount];
 186                         lengths       = new int [entryCount];
 187
 188                         for (int i = 0; i < entryCount; ++i) {
 189                                 var entry = ReadAt<AndroidTzDataEntry>(indexOffset + (entrySize*i), buffer);
 190                                 var p     = (sbyte*) entry.id;
 191
 192                                 byteOffsets [i]   = NetworkToHostOrder (entry.byteOffset) + dataOffset;
 193                                 ids [i]           = new string (p, 0, GetStringLength (p, 40), Encoding.ASCII);
 194                                 lengths [i]       = NetworkToHostOrder (entry.length);
 195
 196                                 if (lengths [i] < Marshal.SizeOf (typeof (AndroidTzDataHeader)))
 197                                         throw new InvalidOperationException ("Length in index file < sizeof(tzhead)");
 198                         }
 199                 }
 200
 201                 static unsafe int GetStringLength (sbyte* s, int maxLength)
 202                 {
 203                         int len;
 204                         for (len = 0; len < maxLength; len++, s++) {
 205                                 if (*s == 0)
 206                                         break;
 207                         }
 208                         return len;
 209                 }
 210
 211                 unsafe void ReadZoneTab (int zoneTabOffset, int zoneTabSize)
 212                 {
 213                         byte[] zoneTab = new byte [zoneTabSize];
 214
 215                         data.Position = zoneTabOffset;
 216
 217                         int r;
 218                         if ((r = data.Read (zoneTab, 0, zoneTab.Length)) < zoneTab.Length)
 219                                 throw new InvalidOperationException (
 220                                                 string.Format ("Error reading zonetab: read {0} bytes, expected {1}", r, zoneTabSize));
 221
 222                         this.zoneTab = Encoding.ASCII.GetString (zoneTab, 0, zoneTab.Length);
 223                 }
 224
 225                 public IEnumerable<string> GetAvailableIds ()
 226                 {
 227                         return ids;
 228                 }
 229
 230                 public byte[] GetTimeZoneData (string id)
 231                 {
 232                         int i = Array.BinarySearch (ids, id, StringComparer.Ordinal);
 233                         if (i < 0)
 234                                 return null;
 235
 236                         int offset = byteOffsets [i];
 237                         int length = lengths [i];
 238                         var buffer = new byte [length];
 239
 240                         lock (data) {
 241                                 data.Position = offset;
 242                                 int r;
 243                                 if ((r = data.Read (buffer, 0, buffer.Length)) < buffer.Length)
 244                                         throw new InvalidOperationException (
 245                                                         string.Format ("Unable to fully read from file '{0}' at offset {1} length {2}; read {3} bytes expected {4}.",
 246                                                                 tzdataPath, offset, length, r, buffer.Length));
 247                         }
 248
 249                         TimeZoneInfo.DumpTimeZoneDataToFile (id, buffer);
 250                         return buffer;
 251                 }
 252         }
 253
 254         partial class TimeZoneInfo {
 255
 256                 static TimeZoneInfo CreateLocal ()
 257                 {
 258                         return AndroidTimeZones.Local;
 259                 }
 260
 261                 static TimeZoneInfo FindSystemTimeZoneByIdCore (string id)
 262                 {
 263                         var timeZoneInfo = AndroidTimeZones.GetTimeZone (id, id);
 264                         if (timeZoneInfo == null)
 265                                 throw new TimeZoneNotFoundException ();
 266                         return timeZoneInfo;
 267                 }
 268
 269                 static void GetSystemTimeZonesCore (List<TimeZoneInfo> systemTimeZones)
 270                 {
 271                         foreach (string id in AndroidTimeZones.GetAvailableIds ()) {
 272                                 var tz = AndroidTimeZones.GetTimeZone (id, id);
 273                                 if (tz != null)
 274                                         systemTimeZones.Add (tz);
 275                         }
 276                 }
 277
 278                 /*
 279                  * Android < v4.3 Timezone support infrastructure.
 280                  *
 281                  * This is a C# port of org.apache.harmony.luni.internal.util.ZoneInfoDB:
 282                  *
 283                  *    http://android.git.kernel.org/?p=platform/libcore.git;a=blob;f=luni/src/main/java/org/apache/harmony/luni/internal/util/ZoneInfoDB.java;h=3e7bdc3a952b24da535806d434a3a27690feae26;hb=HEAD
 284                  *
 285                  * From the ZoneInfoDB source:
 286                  *
 287                  *    However, to conserve disk space the data for all time zones are
 288                  *    concatenated into a single file, and a second file is used to indicate
 289                  *    the starting position of each time zone record.  A third file indicates
 290                  *    the version of the zoneinfo databse used to generate the data.
 291                  *
 292                  * which succinctly describes why we can't just use the LIBC implementation in
 293                  * TimeZoneInfo.cs -- the "standard Unixy" directory structure is NOT used.
 294                  */
 295                 sealed class ZoneInfoDB : IAndroidTimeZoneDB {
 296                         const int TimeZoneNameLength  = 40;
 297                         const int TimeZoneIntSize     = 4;
 298
 299                         internal static readonly string ZoneDirectoryName  = Environment.GetEnvironmentVariable ("ANDROID_ROOT") + "/usr/share/zoneinfo/";
 300
 301                         const    string ZoneFileName       = "zoneinfo.dat";
 302                         const    string IndexFileName      = "zoneinfo.idx";
 303                         const    string DefaultVersion     = "2007h";
 304                         const    string VersionFileName    = "zoneinfo.version";
 305
 306                         readonly string    zoneRoot;
 307                         readonly string    version;
 308                         readonly string[]  names;
 309                         readonly int[]     starts;
 310                         readonly int[]     lengths;
 311                         readonly int[]     offsets;
 312
 313                         public ZoneInfoDB (string zoneInfoDB = null)
 314                         {
 315                                 zoneRoot = zoneInfoDB ?? ZoneDirectoryName;
 316                                 try {
 317                                         version = ReadVersion (Path.Combine (zoneRoot, VersionFileName));
 318                                 } catch {
 319                                         version = DefaultVersion;
 320                                 }
 321
 322                                 try {
 323                                         ReadDatabase (Path.Combine (zoneRoot, IndexFileName), out names, out starts, out lengths, out offsets);
 324                                 } catch {
 325                                         names   = new string [0];
 326                                         starts  = new int [0];
 327                                         lengths = new int [0];
 328                                         offsets = new int [0];
 329                                 }
 330                         }
 331
 332                         static string ReadVersion (string path)
 333                         {
 334                                 using (var file = new StreamReader (path, Encoding.GetEncoding ("iso-8859-1"))) {
 335                                         return file.ReadToEnd ().Trim ();
 336                                 }
 337                         }
 338
 339                         void ReadDatabase (string path, out string[] names, out int[] starts, out int[] lengths, out int[] offsets)
 340                         {
 341                                 using (var file = File.OpenRead (path)) {
 342                                         var nbuf = new byte [TimeZoneNameLength];
 343
 344                                         int numEntries = (int) (file.Length / (TimeZoneNameLength + 3*TimeZoneIntSize));
 345
 346                                         char[]  namebuf = new char [TimeZoneNameLength];
 347
 348                                         names   = new string [numEntries];
 349                                         starts  = new int [numEntries];
 350                                         lengths = new int [numEntries];
 351                                         offsets = new int [numEntries];
 352
 353                                         for (int i = 0; i < numEntries; ++i) {
 354                                                 Fill (file, nbuf, nbuf.Length);
 355                                                 int namelen;
 356                                                 for (namelen = 0; namelen < nbuf.Length; ++namelen) {
 357                                                         if (nbuf [namelen] == '\0')
 358                                                                 break;
 359                                                         namebuf [namelen] = (char) (nbuf [namelen] & 0xFF);
 360                                                 }
 361
 362                                                 names   [i] = new string (namebuf, 0, namelen);
 363                                                 starts  [i] = ReadInt32 (file, nbuf);
 364                                                 lengths [i] = ReadInt32 (file, nbuf);
 365                                                 offsets [i] = ReadInt32 (file, nbuf);
 366                                         }
 367                                 }
 368                         }
 369
 370                         static void Fill (Stream stream, byte[] nbuf, int required)
 371                         {
 372                                 int read = 0, offset = 0;
 373                                 while (offset < required && (read = stream.Read (nbuf, offset, required - offset)) > 0)
 374                                         offset += read;
 375                                 if (read != required)
 376                                         throw new EndOfStreamException ("Needed to read " + required + " bytes; read " + read + " bytes");
 377                         }
 378
 379                         // From java.io.RandomAccessFioe.readInt(), as we need to use the same
 380                         // byte ordering as Java uses.
 381                         static int ReadInt32 (Stream stream, byte[] nbuf)
 382                         {
 383                                 Fill (stream, nbuf, 4);
 384                                 return ((nbuf [0] & 0xff) << 24) + ((nbuf [1] & 0xff) << 16) +
 385                                         ((nbuf [2] & 0xff) << 8) + (nbuf [3] & 0xff);
 386                         }
 387
 388                         internal string Version {
 389                                 get {return version;}
 390                         }
 391
 392                         public IEnumerable<string> GetAvailableIds ()
 393                         {
 394                                 return GetAvailableIds (0, false);
 395                         }
 396
 397                         IEnumerable<string> GetAvailableIds (int rawOffset)
 398                         {
 399                                 return GetAvailableIds (rawOffset, true);
 400                         }
 401
 402                         IEnumerable<string> GetAvailableIds (int rawOffset, bool checkOffset)
 403                         {
 404                                 for (int i = 0; i < offsets.Length; ++i) {
 405                                         if (!checkOffset || offsets [i] == rawOffset)
 406                                                 yield return names [i];
 407                                 }
 408                         }
 409
 410                         public byte[] GetTimeZoneData (string id)
 411                         {
 412                                 int start, length;
 413                                 using (var stream = GetTimeZoneData (id, out start, out length)) {
 414                                         if (stream == null)
 415                                                 return null;
 416                                         byte[] buf = new byte [length];
 417                                         Fill (stream, buf, buf.Length);
 418                                         return buf;
 419                                 }
 420                         }
 421
 422                         FileStream GetTimeZoneData (string name, out int start, out int length)
 423                         {
 424                                 if (name == null) { // Just in case, to avoid NREX as in xambug #4902
 425                                         start = 0;
 426                                         length = 0;
 427                                         return null;
 428                                 }
 429
 430                                 var f = new FileInfo (Path.Combine (zoneRoot, name));
 431                                 if (f.Exists) {
 432                                         start   = 0;
 433                                         length  = (int) f.Length;
 434                                         return f.OpenRead ();
 435                                 }
 436
 437                                 start = length = 0;
 438
 439                                 int i = Array.BinarySearch (names, name, StringComparer.Ordinal);
 440                                 if (i < 0)
 441                                         return null;
 442
 443                                 start   = starts [i];
 444                                 length  = lengths [i];
 445
 446                                 var stream = File.OpenRead (Path.Combine (zoneRoot, ZoneFileName));
 447                                 stream.Seek (start, SeekOrigin.Begin);
 448
 449                                 return stream;
 450                         }
 451                 }
 452
 453                 static class AndroidTimeZones {
 454
 455                         static IAndroidTimeZoneDB db;
 456
 457                         static AndroidTimeZones ()
 458                         {
 459                                 db = GetDefaultTimeZoneDB ();
 460                         }
 461
 462                         static IAndroidTimeZoneDB GetDefaultTimeZoneDB ()
 463                         {
 464                                 foreach (var p in AndroidTzData.Paths)
 465                                         if (File.Exists (p))
 466                                                 return new AndroidTzData (AndroidTzData.Paths);
 467                                 if (Directory.Exists (ZoneInfoDB.ZoneDirectoryName))
 468                                         return new ZoneInfoDB ();
 469                                 return null;
 470                         }
 471
 472                         internal static IEnumerable<string> GetAvailableIds ()
 473                         {
 474                                 return db == null
 475                                         ? new string [0]
 476                                         : db.GetAvailableIds ();
 477                         }
 478
 479                         static TimeZoneInfo _GetTimeZone (string id, string name)
 480                         {
 481                                 if (db == null)
 482                                         return null;
 483                                 byte[] buffer = db.GetTimeZoneData (name);
 484                                 if (buffer == null)
 485                                         return null;
 486                                 return TimeZoneInfo.ParseTZBuffer (id, buffer, buffer.Length);
 487                         }
 488
 489                         internal static TimeZoneInfo GetTimeZone (string id, string name)
 490                         {
 491                                 if (name != null) {
 492                                         if (name == "GMT" || name == "UTC")
 493                                                 return new TimeZoneInfo (id, TimeSpan.FromSeconds (0), id, name, name, null, disableDaylightSavingTime:true);
 494                                         if (name.StartsWith ("GMT"))
 495                                                 return new TimeZoneInfo (id,
 496                                                                 TimeSpan.FromSeconds (ParseNumericZone (name)),
 497                                                                 id, name, name, null, disableDaylightSavingTime:true);
 498                                 }
 499
 500                                 try {
 501                                         return _GetTimeZone (id, name);
 502                                 } catch (Exception) {
 503                                         return null;
 504                                 }
 505                         }
 506
 507                         static int ParseNumericZone (string name)
 508                         {
 509                                 if (name == null || !name.StartsWith ("GMT") || name.Length <= 3)
 510                                         return 0;
 511
 512                                 int sign;
 513                                 if (name [3] == '+')
 514                                         sign = 1;
 515                                 else if (name [3] == '-')
 516                                         sign = -1;
 517                                 else
 518                                         return 0;
 519
 520                                 int where;
 521                                 int hour = 0;
 522                                 bool colon = false;
 523                                 for (where = 4; where < name.Length; where++) {
 524                                         char c = name [where];
 525
 526                                         if (c == ':') {
 527                                                 where++;
 528                                                 colon = true;
 529                                                 break;
 530                                         }
 531
 532                                         if (c >= '0' && c <= '9')
 533                                                 hour = hour * 10 + c - '0';
 534                                         else
 535                                                 return 0;
 536                                 }
 537
 538                                 int min = 0;
 539                                 for (; where < name.Length; where++) {
 540                                         char c = name [where];
 541
 542                                         if (c >= '0' && c <= '9')
 543                                                 min = min * 10 + c - '0';
 544                                         else
 545                                                 return 0;
 546                                 }
 547
 548                                 if (colon)
 549                                         return sign * (hour * 60 + min) * 60;
 550                                 else if (hour >= 100)
 551                                         return sign * ((hour / 100) * 60 + (hour % 100)) * 60;
 552                                 else
 553                                         return sign * (hour * 60) * 60;
 554                         }
 555
 556                         static TimeZoneInfo defaultZone;
 557                         internal static TimeZoneInfo Local {
 558                                 get {
 559                                         var id  = GetDefaultTimeZoneName ();
 560                                         return defaultZone = GetTimeZone (id, id);
 561                                 }
 562                         }
 563
 564                         [DllImport ("__Internal")]
 565                         static extern int monodroid_get_system_property (string name, ref IntPtr value);
 566
 567                         [DllImport ("__Internal")]
 568                         static extern void monodroid_free (IntPtr ptr);
 569
 570                         static string GetDefaultTimeZoneName ()
 571                         {
 572                                 IntPtr value = IntPtr.Zero;
 573                                 int n = 0;
 574                                 string defaultTimeZone  = Environment.GetEnvironmentVariable ("__XA_OVERRIDE_TIMEZONE_ID__");
 575
 576                                 if (!string.IsNullOrEmpty (defaultTimeZone))
 577                                         return defaultTimeZone;
 578
 579                                 // Used by the tests
 580                                 if (Environment.GetEnvironmentVariable ("__XA_USE_JAVA_DEFAULT_TIMEZONE_ID__") == null)
 581                                         n = monodroid_get_system_property ("persist.sys.timezone", ref value);
 582
 583                                 if (n > 0 && value != IntPtr.Zero) {
 584                                         defaultTimeZone = (Marshal.PtrToStringAnsi (value) ?? String.Empty).Trim ();
 585                                         monodroid_free (value);
 586                                         if (!String.IsNullOrEmpty (defaultTimeZone))
 587                                                 return defaultTimeZone;
 588                                 }
 589
 590                                 defaultTimeZone = (AndroidPlatform.GetDefaultTimeZone () ?? String.Empty).Trim ();
 591                                 if (!String.IsNullOrEmpty (defaultTimeZone))
 592                                         return defaultTimeZone;
 593
 594                                 return null;
 595                         }
 596
 597 #if SELF_TEST
 598                         /*
 599                          * Compile:
 600                          *    mcs /debug+ /out:tzi.exe /unsafe "/d:INSIDE_CORLIB;MONODROID;NET_4_0;LIBC;SELF_TEST" ../corlib/System/AndroidPlatform.cs System/TimeZone*.cs ../../build/common/Consts.cs ../Mono.Options/Mono.Options/Options.cs
 601                          * Prep:
 602                          *    mkdir -p android/tzdb/usr/share/zoneinfo
 603                          *    mkdir -p android/tzdb/misc/zoneinfo/zoneinfo
 604                          *    android_root=`adb shell echo '$ANDROID_ROOT' | tr -d "\r"`
 605                          *    android_data=`adb shell echo '$ANDROID_DATA' | tr -d "\r"`
 606                          *    adb pull $android_root/usr/share/zoneinfo   android/tzdb/usr/share/zoneinfo
 607                          *    adb pull $android_data/misc/zoneinfo/tzdata android/tzdb/misc/zoneinfo
 608                          * Run:
 609                          *    # Dump all timezone names
 610                          *    __XA_OVERRIDE_TIMEZONE_ID__=America/New_York ANDROID_ROOT=`pwd` ANDROID_DATA=`pwd` mono --debug tzi.exe --offset=1969-01-01
 611                          *
 612                          *    # Dump TimeZone data to files under path `tzdata`
 613                          *    __XA_OVERRIDE_TIMEZONE_ID__=America/New_York ANDROID_ROOT=`pwd` ANDROID_DATA=`pwd` mono --debug tzi.exe -o android/tzdata
 614                          *
 615                          *    # Dump TimeZone rules for specific timezone data (as dumped above)
 616                          *    mono tzi.exe --offset=2012-10-24 -i=tzdata/Asia/Amman
 617                          */
 618                         static void Main (string[] args)
 619                         {
 620                                 DateTime? offset           = null;
 621                                 Func<IAndroidTimeZoneDB> c = () => GetDefaultTimeZoneDB ();
 622                                 bool dump_rules            = false;
 623                                 Mono.Options.OptionSet p = null;
 624                                 p = new Mono.Options.OptionSet () {
 625                                         { "i=",
 626                                           "TimeZone data {FILE} to parse and dump",
 627                                           v => DumpTimeZoneFile (v, offset)
 628                                         },
 629                                         { "o=",
 630                                           "Write TimeZone data files to {PATH}",
 631                                           v => TimeZoneInfo.TimeZoneDataExportPath = v
 632                                         },
 633                                         { "T=", "Create AndroidTzData from {PATH}.", v => {
 634                                                         c = () => new AndroidTzData (v);
 635                                         } },
 636                                         { "Z=", "Create ZoneInfoDB from {DIR}.", v => {
 637                                                         c = () => new ZoneInfoDB (v);
 638                                         } },
 639                                         { "offset=", "Show timezone info offset for DateTime {OFFSET}.", v => {
 640                                                 offset = DateTime.Parse (v);
 641                                                 Console.WriteLine ("Using DateTime Offset: {0}", offset);
 642                                         } },
 643                                         { "R|dump-rules",
 644                                           "Show timezone info offset for DateTime {OFFSET}.",
 645                                           v => dump_rules = v != null },
 646                                         { "help", "Show this message and exit", v => {
 647                                                         p.WriteOptionDescriptions (Console.Out);
 648                                                         Environment.Exit (0);
 649                                         } },
 650                                 };
 651                                 p.Parse (args);
 652                                 AndroidTimeZones.db = c ();
 653                                 Console.WriteLine ("DB type: {0}", AndroidTimeZones.db.GetType ().FullName);
 654                                 foreach (var id in GetAvailableIds ()) {
 655                                         Console.Write ("name={0,-40}", id);
 656                                         try {
 657                                                 TimeZoneInfo zone = _GetTimeZone (id, id);
 658                                                 if (zone != null) {
 659                                                         Console.Write (" {0,-40}", zone);
 660                                                         if (offset.HasValue) {
 661                                                                 Console.Write ("From Offset: {0}", zone.GetUtcOffset (offset.Value));
 662                                                         }
 663                                                         if (dump_rules) {
 664                                                                 WriteZoneRules (zone);
 665                                                         }
 666                                                 }
 667                                                 else {
 668                                                         Console.Write (" ERROR:null");
 669                                                 }
 670                                         } catch (Exception e) {
 671                                                 Console.WriteLine ();
 672                                                 Console.Write ("ERROR: {0}", e);
 673                                         }
 674                                         Console.WriteLine ();
 675                                 }
 676                         }
 677
 678                         static void WriteZoneRules (TimeZoneInfo zone)
 679                         {
 680                                 var rules = zone.GetAdjustmentRules ();
 681                                 for (int i = 0; i < rules.Length; ++i) {
 682                                         var rule = rules [i];
 683                                         Console.WriteLine ();
 684                                         Console.Write ("\tAdjustmentRules[{0,3}]: DaylightDelta={1}; DateStart={2:yyyy-MM}; DateEnd={3:yyyy-MM}; DaylightTransitionStart={4:D2}-{5:D2}T{6}; DaylightTransitionEnd={7:D2}-{8:D2}T{9}",
 685                                                 i,
 686                                                 rule.DaylightDelta,
 687                                                 rule.DateStart, rule.DateEnd,
 688                                                 rule.DaylightTransitionStart.Month, rule.DaylightTransitionStart.Day, rule.DaylightTransitionStart.TimeOfDay.TimeOfDay,
 689                                                 rule.DaylightTransitionEnd.Month, rule.DaylightTransitionEnd.Day, rule.DaylightTransitionEnd.TimeOfDay.TimeOfDay);
 690                                 }
 691                         }
 692
 693                         static void DumpTimeZoneFile (string path, DateTime? time)
 694                         {
 695                                 var buffer = File.ReadAllBytes (path);
 696                                 var zone = ParseTZBuffer (path, buffer, buffer.Length);
 697                                 Console.Write ("Rules for: {0}", path);
 698                                 WriteZoneRules (zone);
 699                                 Console.WriteLine ();
 700                                 if (time.HasValue) {
 701                                         var offset = zone.GetUtcOffset (time.Value);
 702                                         var isDst  = zone.IsDaylightSavingTime (time.Value);
 703                                         Console.WriteLine ("\tDate({0}): Offset({1}) IsDST({2})", time.Value, offset, isDst);
 704                                 }
 705
 706                                 if (zone.transitions != null) {
 707                                         Console.WriteLine ("Transitions for: {0}", path);
 708                                         foreach (var transition in zone.transitions) {
 709                                                 Console.WriteLine ("\t Date({0}): {1}", transition.Key, transition.Value);
 710                                         }
 711                                 }
 712                         }
 713 #endif
 714                 }
 715
 716 #if SELF_TEST
 717                 static string TimeZoneDataExportPath;
 718 #endif
 719
 720                 internal static void DumpTimeZoneDataToFile (string id, byte[] buffer)
 721                 {
 722 #if SELF_TEST
 723                         int p = id.LastIndexOf ('/');
 724                         var o = Path.Combine (TimeZoneDataExportPath,
 725                                         p >= 0 ? id.Substring (0, p) : id);
 726                         if (p >= 0)
 727                                 o = Path.Combine (o, id.Substring (p+1));
 728                         Directory.CreateDirectory (Path.GetDirectoryName (o));
 729                         using (var f = File.OpenWrite (o))
 730                                 f.Write (buffer, 0, buffer.Length);
 731 #endif
 732                 }
 733         }
 734 }
 735
 736 #endif // MONODROID
 737