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Overview
Comment: | Improve handling of out-of-range Julian Day values. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | newJulianDay |
Files: | files | file ages | folders |
SHA1: |
c559792dba4cff18e8af99127eb0a12e |
User & Date: | mistachkin 2014-10-31 22:40:47.088 |
Context
2014-10-31
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23:36 | Completely remove use of DateTime.FromOADate and DateTime.ToOADate methods. Improve comments. Now passes existing tests. More tests are still necessary. check-in: 36b4f89052 user: mistachkin tags: newJulianDay | |
22:40 | Improve handling of out-of-range Julian Day values. check-in: c559792dba user: mistachkin tags: newJulianDay | |
21:36 | Add experimental port of the Julian Day handling functions from the SQLite core library. Still needs tests. Pursuant to [3e783eecbe]. check-in: fe17cded54 user: mistachkin tags: newJulianDay | |
Changes
Changes to System.Data.SQLite/SQLiteConvert.cs.
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47 48 49 50 51 52 53 54 55 56 57 58 59 60 | private static readonly double OleAutomationEpochAsJulianDay = 2415018.5; /// <summary> /// The format string for DateTime values when using the InvariantCulture or CurrentCulture formats. /// </summary> private const string FullFormat = "yyyy-MM-ddTHH:mm:ss.fffffffK"; /// <summary> /// An array of ISO-8601 DateTime formats that we support parsing. /// </summary> private static string[] _datetimeFormats = new string[] { "THHmmssK", "THHmmK", "HH:mm:ss.FFFFFFFK", | > > > > > > > > > > > > | 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 | private static readonly double OleAutomationEpochAsJulianDay = 2415018.5; /// <summary> /// The format string for DateTime values when using the InvariantCulture or CurrentCulture formats. /// </summary> private const string FullFormat = "yyyy-MM-ddTHH:mm:ss.fffffffK"; /// <summary> /// This is the minimum Julian Day value supported by this library /// (148731163200000). /// </summary> private static readonly long MinimumJD = computeJD(DateTime.MinValue); /// <summary> /// This is the maximum Julian Day value supported by this library /// (464269060799000). /// </summary> private static readonly long MaximumJD = computeJD(DateTime.MaxValue); /// <summary> /// An array of ISO-8601 DateTime formats that we support parsing. /// </summary> private static string[] _datetimeFormats = new string[] { "THHmmssK", "THHmmK", "HH:mm:ss.FFFFFFFK", |
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204 205 206 207 208 209 210 | #endregion #region DateTime Conversion Functions #region New Julian Day Conversion Methods /// <summary> | > > > > > > > > > > > > > > > > > > | | > > > > | | | > > > > > > | > > > > > | | > > > > | > > > > | 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 | #endregion #region DateTime Conversion Functions #region New Julian Day Conversion Methods /// <summary> /// Checks if the specified <see cref="Int64" /> is within the /// supported range for a Julian Day value. /// </summary> /// <param name="jd"> /// The Julian Day value to check. /// </param> /// <returns> /// Non-zero if the specified Julian Day value is in the supported /// range; otherwise, zero. /// </returns> private static bool isValidJD( long jd ) { return ((jd >= MinimumJD) && (jd <= MaximumJD)); } /// <summary> /// Converts a Julian Day value to a <see cref="DateTime" />. /// This function was copied from the "date.c" file belonging /// to the SQLite core library. /// </summary> /// <param name="jd"> /// The Julian Day value to convert. /// </param> /// <param name="badValue"> /// The <see cref="DateTime" /> value to return in the event that the /// Julian Day is out of the supported range. /// </param> /// <returns> /// A <see cref="DateTime" /> value that contains the year, month, and /// day values that are closest to the specified Julian Day value. /// </returns> private static DateTime computeYMD( long jd, DateTime badValue ) { if (!isValidJD(jd)) return badValue; int Z, A, B, C, D, E, X1; Z = (int)((jd + 43200000) / 86400000); A = (int)((Z - 1867216.25) / 36524.25); A = Z + 1 + A - (A / 4); B = A + 1524; C = (int)((B - 122.1) / 365.25); D = (36525 * C) / 100; E = (int)((B - D) / 30.6001); X1 = (int)(30.6001 * E); int day, month, year; day = B - D - X1; month = E < 14 ? E - 1 : E - 13; year = month > 2 ? C - 4716 : C - 4715; try { return new DateTime(year, month, day); } catch { return badValue; } } /////////////////////////////////////////////////////////////////////////// /// <summary> /// Converts a Julian Day value to a <see cref="DateTime" />. /// This function was copied from the "date.c" file belonging /// to the SQLite core library. /// </summary> /// <param name="jd"> /// The Julian Day value to convert. /// </param> /// <param name="badValue"> /// The <see cref="DateTime" /> value to return in the event that the /// Julian Day value is out of the supported range. /// </param> /// <returns> /// A <see cref="DateTime" /> value that contains the hour, minute, and /// second values that are closest to the specified Julian Day value. /// </returns> private static DateTime computeHMS( long jd, DateTime badValue ) { if (!isValidJD(jd)) return badValue; int s; s = (int)((jd + 43200000) % 86400000); double seconds; seconds = s / 1000.0; |
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280 281 282 283 284 285 286 | minute = s / 60; seconds += s - minute * 60; int second = (int)Math.Truncate(seconds); int millisecond = (int)((seconds - second) * 1000.0); | > > | | | | > > > > > | | > > > > | > > > > | | 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 | minute = s / 60; seconds += s - minute * 60; int second = (int)Math.Truncate(seconds); int millisecond = (int)((seconds - second) * 1000.0); try { DateTime minValue = DateTime.MinValue; return new DateTime( minValue.Year, minValue.Month, minValue.Day, hour, minute, second, millisecond); } catch { return badValue; } } /////////////////////////////////////////////////////////////////////////// /// <summary> /// Converts a <see cref="DateTime" /> to a Julian Day value. /// This function was copied from the "date.c" file belonging /// to the SQLite core library. Since the range of Julian Day /// values supported by this method includes all possible valid /// values of a <see cref="DateTime" /> value, it should be /// impossible for this method to raise an exception or return /// an undefined result. /// </summary> /// <param name="dateTime"> /// The <see cref="DateTime" /> value to convert. This value /// will be within the range of <see cref="DateTime.MinValue" /> /// (00:00:00.0000000, January 1, 0001) to /// <see cref="DateTime.MaxValue" /> (23:59:59.9999999, December /// 31, 9999). /// </param> /// <returns> /// The nearest Julian Day value corresponding to the specified /// <see cref="DateTime" /> value. /// </returns> private static long computeJD( DateTime dateTime ) { int Y, M, D; |
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