1 /* GStreamer
   2  * Copyright (C) 2010 Thiago Santos <thiago.sousa.santos@collabora.co.uk>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Library General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Library General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Library General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
  17  * Boston, MA 02110-1301, USA.
  18  */
  19 
  20 #ifdef HAVE_CONFIG_H
  21 #include "config.h"
  22 #endif
  23 
  24 #include "gst_private.h"
  25 #include "glib-compat-private.h"
  26 #include "gstdatetime.h"
  27 #include "gstvalue.h"
  28 #include <glib.h>
  29 #include <math.h>
  30 #include <stdio.h>
  31 
  32 /**
  33  * SECTION:gstdatetime
  34  * @title: GstDateTime
  35  * @short_description: A date, time and timezone structure
  36  *
  37  * Struct to store date, time and timezone information altogether.
  38  * #GstDateTime is refcounted and immutable.
  39  *
  40  * Date information is handled using the proleptic Gregorian calendar.
  41  *
  42  * Provides basic creation functions and accessor functions to its fields.
  43  */
  44 
  45 typedef enum
  46 {
  47   GST_DATE_TIME_FIELDS_INVALID = 0,
  48   GST_DATE_TIME_FIELDS_Y,       /* have year                */
  49   GST_DATE_TIME_FIELDS_YM,      /* have year and month      */
  50   GST_DATE_TIME_FIELDS_YMD,     /* have year, month and day */
  51   GST_DATE_TIME_FIELDS_YMD_HM,
  52   GST_DATE_TIME_FIELDS_YMD_HMS
  53       /* Note: if we ever add more granularity here, e.g. for microsecs,
  54        * the compare function will need updating */
  55 } GstDateTimeFields;
  56 
  57 struct _GstDateTime
  58 {
  59   GstMiniObject mini_object;
  60 
  61   GDateTime *datetime;
  62 
  63   GstDateTimeFields fields;
  64 };
  65 
  66 GType _gst_date_time_type = 0;
  67 GST_DEFINE_MINI_OBJECT_TYPE (GstDateTime, gst_date_time);
  68 
  69 static void gst_date_time_free (GstDateTime * datetime);
  70 
  71 /**
  72  * gst_date_time_new_from_g_date_time:
  73  * @dt: (transfer full): the #GDateTime. The new #GstDateTime takes ownership.
  74  *
  75  * Creates a new #GstDateTime from a #GDateTime object.
  76  *
  77  * Free-function: gst_date_time_unref
  78  *
  79  * Returns: (transfer full) (nullable): a newly created #GstDateTime,
  80  * or %NULL on error
  81  */
  82 GstDateTime *
  83 gst_date_time_new_from_g_date_time (GDateTime * dt)
  84 {
  85   GstDateTime *gst_dt;
  86 
  87   if (!dt)
  88     return NULL;
  89 
  90   gst_dt = g_slice_new (GstDateTime);
  91 
  92   gst_mini_object_init (GST_MINI_OBJECT_CAST (gst_dt), 0, GST_TYPE_DATE_TIME,
  93       NULL, NULL, (GstMiniObjectFreeFunction) gst_date_time_free);
  94 
  95   gst_dt->datetime = dt;
  96   gst_dt->fields = GST_DATE_TIME_FIELDS_YMD_HMS;
  97   return gst_dt;
  98 }
  99 
 100 /**
 101  * gst_date_time_to_g_date_time:
 102  * @datetime: GstDateTime.
 103  *
 104  * Creates a new #GDateTime from a fully defined #GstDateTime object.
 105  *
 106  * Free-function: g_date_time_unref
 107  *
 108  * Returns: (transfer full) (nullable): a newly created #GDateTime, or
 109  * %NULL on error
 110  */
 111 GDateTime *
 112 gst_date_time_to_g_date_time (GstDateTime * datetime)
 113 {
 114   g_return_val_if_fail (datetime != NULL, NULL);
 115 
 116   if (datetime->fields != GST_DATE_TIME_FIELDS_YMD_HMS)
 117     return NULL;
 118 
 119   return g_date_time_add (datetime->datetime, 0);
 120 }
 121 
 122 /**
 123  * gst_date_time_has_year:
 124  * @datetime: a #GstDateTime
 125  *
 126  * Returns: %TRUE if @datetime<!-- -->'s year field is set (which should always
 127  *     be the case), otherwise %FALSE
 128  */
 129 gboolean
 130 gst_date_time_has_year (const GstDateTime * datetime)
 131 {
 132   g_return_val_if_fail (datetime != NULL, FALSE);
 133 
 134   return (datetime->fields >= GST_DATE_TIME_FIELDS_Y);
 135 }
 136 
 137 /**
 138  * gst_date_time_has_month:
 139  * @datetime: a #GstDateTime
 140  *
 141  * Returns: %TRUE if @datetime<!-- -->'s month field is set, otherwise %FALSE
 142  */
 143 gboolean
 144 gst_date_time_has_month (const GstDateTime * datetime)
 145 {
 146   g_return_val_if_fail (datetime != NULL, FALSE);
 147 
 148   return (datetime->fields >= GST_DATE_TIME_FIELDS_YM);
 149 }
 150 
 151 /**
 152  * gst_date_time_has_day:
 153  * @datetime: a #GstDateTime
 154  *
 155  * Returns: %TRUE if @datetime<!-- -->'s day field is set, otherwise %FALSE
 156  */
 157 gboolean
 158 gst_date_time_has_day (const GstDateTime * datetime)
 159 {
 160   g_return_val_if_fail (datetime != NULL, FALSE);
 161 
 162   return (datetime->fields >= GST_DATE_TIME_FIELDS_YMD);
 163 }
 164 
 165 /**
 166  * gst_date_time_has_time:
 167  * @datetime: a #GstDateTime
 168  *
 169  * Returns: %TRUE if @datetime<!-- -->'s hour and minute fields are set,
 170  *     otherwise %FALSE
 171  */
 172 gboolean
 173 gst_date_time_has_time (const GstDateTime * datetime)
 174 {
 175   g_return_val_if_fail (datetime != NULL, FALSE);
 176 
 177   return (datetime->fields >= GST_DATE_TIME_FIELDS_YMD_HM);
 178 }
 179 
 180 /**
 181  * gst_date_time_has_second:
 182  * @datetime: a #GstDateTime
 183  *
 184  * Returns: %TRUE if @datetime<!-- -->'s second field is set, otherwise %FALSE
 185  */
 186 gboolean
 187 gst_date_time_has_second (const GstDateTime * datetime)
 188 {
 189   g_return_val_if_fail (datetime != NULL, FALSE);
 190 
 191   return (datetime->fields >= GST_DATE_TIME_FIELDS_YMD_HMS);
 192 }
 193 
 194 /**
 195  * gst_date_time_get_year:
 196  * @datetime: a #GstDateTime
 197  *
 198  * Returns the year of this #GstDateTime
 199  * Call gst_date_time_has_year before, to avoid warnings.
 200  *
 201  * Return value: The year of this #GstDateTime
 202  */
 203 gint
 204 gst_date_time_get_year (const GstDateTime * datetime)
 205 {
 206   g_return_val_if_fail (datetime != NULL, 0);
 207 
 208   return g_date_time_get_year (datetime->datetime);
 209 }
 210 
 211 /**
 212  * gst_date_time_get_month:
 213  * @datetime: a #GstDateTime
 214  *
 215  * Returns the month of this #GstDateTime. January is 1, February is 2, etc..
 216  * Call gst_date_time_has_month before, to avoid warnings.
 217  *
 218  * Return value: The month of this #GstDateTime
 219  */
 220 gint
 221 gst_date_time_get_month (const GstDateTime * datetime)
 222 {
 223   g_return_val_if_fail (datetime != NULL, 0);
 224   g_return_val_if_fail (gst_date_time_has_month (datetime), 0);
 225 
 226   return g_date_time_get_month (datetime->datetime);
 227 }
 228 
 229 /**
 230  * gst_date_time_get_day:
 231  * @datetime: a #GstDateTime
 232  *
 233  * Returns the day of the month of this #GstDateTime.
 234  * Call gst_date_time_has_day before, to avoid warnings.
 235  *
 236  * Return value: The day of this #GstDateTime
 237  */
 238 gint
 239 gst_date_time_get_day (const GstDateTime * datetime)
 240 {
 241   g_return_val_if_fail (datetime != NULL, 0);
 242   g_return_val_if_fail (gst_date_time_has_day (datetime), 0);
 243 
 244   return g_date_time_get_day_of_month (datetime->datetime);
 245 }
 246 
 247 /**
 248  * gst_date_time_get_hour:
 249  * @datetime: a #GstDateTime
 250  *
 251  * Retrieves the hour of the day represented by @datetime in the gregorian
 252  * calendar. The return is in the range of 0 to 23.
 253  * Call gst_date_time_has_haur before, to avoid warnings.
 254  *
 255  * Return value: the hour of the day
 256  */
 257 gint
 258 gst_date_time_get_hour (const GstDateTime * datetime)
 259 {
 260   g_return_val_if_fail (datetime != NULL, 0);
 261   g_return_val_if_fail (gst_date_time_has_time (datetime), 0);
 262 
 263   return g_date_time_get_hour (datetime->datetime);
 264 }
 265 
 266 /**
 267  * gst_date_time_get_minute:
 268  * @datetime: a #GstDateTime
 269  *
 270  * Retrieves the minute of the hour represented by @datetime in the gregorian
 271  * calendar.
 272  * Call gst_date_time_has_minute before, to avoid warnings.
 273  *
 274  * Return value: the minute of the hour
 275  */
 276 gint
 277 gst_date_time_get_minute (const GstDateTime * datetime)
 278 {
 279   g_return_val_if_fail (datetime != NULL, 0);
 280   g_return_val_if_fail (gst_date_time_has_time (datetime), 0);
 281 
 282   return g_date_time_get_minute (datetime->datetime);
 283 }
 284 
 285 /**
 286  * gst_date_time_get_second:
 287  * @datetime: a #GstDateTime
 288  *
 289  * Retrieves the second of the minute represented by @datetime in the gregorian
 290  * calendar.
 291  * Call gst_date_time_has_second before, to avoid warnings.
 292  *
 293  * Return value: the second represented by @datetime
 294  */
 295 gint
 296 gst_date_time_get_second (const GstDateTime * datetime)
 297 {
 298   g_return_val_if_fail (datetime != NULL, 0);
 299   g_return_val_if_fail (gst_date_time_has_second (datetime), 0);
 300 
 301   return g_date_time_get_second (datetime->datetime);
 302 }
 303 
 304 /**
 305  * gst_date_time_get_microsecond:
 306  * @datetime: a #GstDateTime
 307  *
 308  * Retrieves the fractional part of the seconds in microseconds represented by
 309  * @datetime in the gregorian calendar.
 310  *
 311  * Return value: the microsecond of the second
 312  */
 313 gint
 314 gst_date_time_get_microsecond (const GstDateTime * datetime)
 315 {
 316   g_return_val_if_fail (datetime != NULL, 0);
 317   g_return_val_if_fail (gst_date_time_has_second (datetime), 0);
 318 
 319   return g_date_time_get_microsecond (datetime->datetime);
 320 }
 321 
 322 /**
 323  * gst_date_time_get_time_zone_offset:
 324  * @datetime: a #GstDateTime
 325  *
 326  * Retrieves the offset from UTC in hours that the timezone specified
 327  * by @datetime represents. Timezones ahead (to the east) of UTC have positive
 328  * values, timezones before (to the west) of UTC have negative values.
 329  * If @datetime represents UTC time, then the offset is zero.
 330  *
 331  * Return value: the offset from UTC in hours
 332  */
 333 gfloat
 334 gst_date_time_get_time_zone_offset (const GstDateTime * datetime)
 335 {
 336   g_return_val_if_fail (datetime != NULL, 0.0);
 337   g_return_val_if_fail (gst_date_time_has_time (datetime), 0.0);
 338 
 339   return (g_date_time_get_utc_offset (datetime->datetime) /
 340       G_USEC_PER_SEC) / 3600.0;
 341 }
 342 
 343 /**
 344  * gst_date_time_new_y:
 345  * @year: the gregorian year
 346  *
 347  * Creates a new #GstDateTime using the date and times in the gregorian calendar
 348  * in the local timezone.
 349  *
 350  * @year should be from 1 to 9999.
 351  *
 352  * Free-function: gst_date_time_unref
 353  *
 354  * Return value: (transfer full): the newly created #GstDateTime
 355  */
 356 GstDateTime *
 357 gst_date_time_new_y (gint year)
 358 {
 359   return gst_date_time_new (0.0, year, -1, -1, -1, -1, -1);
 360 }
 361 
 362 /**
 363  * gst_date_time_new_ym:
 364  * @year: the gregorian year
 365  * @month: the gregorian month
 366  *
 367  * Creates a new #GstDateTime using the date and times in the gregorian calendar
 368  * in the local timezone.
 369  *
 370  * @year should be from 1 to 9999, @month should be from 1 to 12.
 371  *
 372  * If value is -1 then all over value will be ignored. For example
 373  * if @month == -1, then #GstDateTime will created only for @year.
 374  *
 375  * Free-function: gst_date_time_unref
 376  *
 377  * Return value: (transfer full): the newly created #GstDateTime
 378  */
 379 GstDateTime *
 380 gst_date_time_new_ym (gint year, gint month)
 381 {
 382   return gst_date_time_new (0.0, year, month, -1, -1, -1, -1);
 383 }
 384 
 385 /**
 386  * gst_date_time_new_ymd:
 387  * @year: the gregorian year
 388  * @month: the gregorian month
 389  * @day: the day of the gregorian month
 390  *
 391  * Creates a new #GstDateTime using the date and times in the gregorian calendar
 392  * in the local timezone.
 393  *
 394  * @year should be from 1 to 9999, @month should be from 1 to 12, @day from
 395  * 1 to 31.
 396  *
 397  * If value is -1 then all over value will be ignored. For example
 398  * if @month == -1, then #GstDateTime will created only for @year. If
 399  * @day == -1, then #GstDateTime will created for @year and @month and
 400  * so on.
 401  *
 402  * Free-function: gst_date_time_unref
 403  *
 404  * Return value: (transfer full): the newly created #GstDateTime
 405  */
 406 GstDateTime *
 407 gst_date_time_new_ymd (gint year, gint month, gint day)
 408 {
 409   return gst_date_time_new (0.0, year, month, day, -1, -1, -1);
 410 }
 411 
 412 /**
 413  * gst_date_time_new_from_unix_epoch_local_time:
 414  * @secs: seconds from the Unix epoch
 415  *
 416  * Creates a new #GstDateTime using the time since Jan 1, 1970 specified by
 417  * @secs. The #GstDateTime is in the local timezone.
 418  *
 419  * Free-function: gst_date_time_unref
 420  *
 421  * Return value: (transfer full): the newly created #GstDateTime
 422  */
 423 GstDateTime *
 424 gst_date_time_new_from_unix_epoch_local_time (gint64 secs)
 425 {
 426   GDateTime *datetime;
 427 
 428   datetime = g_date_time_new_from_unix_local (secs);
 429   return gst_date_time_new_from_g_date_time (datetime);
 430 }
 431 
 432 /**
 433  * gst_date_time_new_from_unix_epoch_utc:
 434  * @secs: seconds from the Unix epoch
 435  *
 436  * Creates a new #GstDateTime using the time since Jan 1, 1970 specified by
 437  * @secs. The #GstDateTime is in the UTC timezone.
 438  *
 439  * Free-function: gst_date_time_unref
 440  *
 441  * Return value: (transfer full): the newly created #GstDateTime
 442  */
 443 GstDateTime *
 444 gst_date_time_new_from_unix_epoch_utc (gint64 secs)
 445 {
 446   GstDateTime *datetime;
 447   datetime =
 448       gst_date_time_new_from_g_date_time (g_date_time_new_from_unix_utc (secs));
 449   return datetime;
 450 }
 451 
 452 static GstDateTimeFields
 453 gst_date_time_check_fields (gint * year, gint * month, gint * day,
 454     gint * hour, gint * minute, gdouble * seconds)
 455 {
 456   if (*month == -1) {
 457     *month = *day = 1;
 458     *hour = *minute = *seconds = 0;
 459     return GST_DATE_TIME_FIELDS_Y;
 460   } else if (*day == -1) {
 461     *day = 1;
 462     *hour = *minute = *seconds = 0;
 463     return GST_DATE_TIME_FIELDS_YM;
 464   } else if (*hour == -1) {
 465     *hour = *minute = *seconds = 0;
 466     return GST_DATE_TIME_FIELDS_YMD;
 467   } else if (*seconds == -1) {
 468     *seconds = 0;
 469     return GST_DATE_TIME_FIELDS_YMD_HM;
 470   } else
 471     return GST_DATE_TIME_FIELDS_YMD_HMS;
 472 }
 473 
 474 /**
 475  * gst_date_time_new_local_time:
 476  * @year: the gregorian year
 477  * @month: the gregorian month, or -1
 478  * @day: the day of the gregorian month, or -1
 479  * @hour: the hour of the day, or -1
 480  * @minute: the minute of the hour, or -1
 481  * @seconds: the second of the minute, or -1
 482  *
 483  * Creates a new #GstDateTime using the date and times in the gregorian calendar
 484  * in the local timezone.
 485  *
 486  * @year should be from 1 to 9999, @month should be from 1 to 12, @day from
 487  * 1 to 31, @hour from 0 to 23, @minutes and @seconds from 0 to 59.
 488  *
 489  * If @month is -1, then the #GstDateTime created will only contain @year,
 490  * and all other fields will be considered not set.
 491  *
 492  * If @day is -1, then the #GstDateTime created will only contain @year and
 493  * @month and all other fields will be considered not set.
 494  *
 495  * If @hour is -1, then the #GstDateTime created will only contain @year and
 496  * @month and @day, and the time fields will be considered not set. In this
 497  * case @minute and @seconds should also be -1.
 498  *
 499  * Free-function: gst_date_time_unref
 500  *
 501  * Return value: (transfer full): the newly created #GstDateTime
 502  */
 503 GstDateTime *
 504 gst_date_time_new_local_time (gint year, gint month, gint day, gint hour,
 505     gint minute, gdouble seconds)
 506 {
 507   GstDateTimeFields fields;
 508   GstDateTime *datetime;
 509 
 510   g_return_val_if_fail (year > 0 && year <= 9999, NULL);
 511   g_return_val_if_fail ((month > 0 && month <= 12) || month == -1, NULL);
 512   g_return_val_if_fail ((day > 0 && day <= 31) || day == -1, NULL);
 513   g_return_val_if_fail ((hour >= 0 && hour < 24) || hour == -1, NULL);
 514   g_return_val_if_fail ((minute >= 0 && minute < 60) || minute == -1, NULL);
 515   g_return_val_if_fail ((seconds >= 0 && seconds < 60) || seconds == -1, NULL);
 516 
 517   fields = gst_date_time_check_fields (&year, &month, &day,
 518       &hour, &minute, &seconds);
 519 
 520   datetime = gst_date_time_new_from_g_date_time (g_date_time_new_local (year,
 521           month, day, hour, minute, seconds));
 522 #ifdef GSTREAMER_LITE
 523   if (datetime == NULL)
 524     return NULL;
 525 #endif // GSTREAMER_LITE
 526 
 527   datetime->fields = fields;
 528   return datetime;
 529 }
 530 
 531 /**
 532  * gst_date_time_new_now_local_time:
 533  *
 534  * Creates a new #GstDateTime representing the current date and time.
 535  *
 536  * Free-function: gst_date_time_unref
 537  *
 538  * Return value: (transfer full): the newly created #GstDateTime which should
 539  *     be freed with gst_date_time_unref().
 540  */
 541 GstDateTime *
 542 gst_date_time_new_now_local_time (void)
 543 {
 544   return gst_date_time_new_from_g_date_time (g_date_time_new_now_local ());
 545 }
 546 
 547 /**
 548  * gst_date_time_new_now_utc:
 549  *
 550  * Creates a new #GstDateTime that represents the current instant at Universal
 551  * coordinated time.
 552  *
 553  * Free-function: gst_date_time_unref
 554  *
 555  * Return value: (transfer full): the newly created #GstDateTime which should
 556  *   be freed with gst_date_time_unref().
 557  */
 558 GstDateTime *
 559 gst_date_time_new_now_utc (void)
 560 {
 561   return gst_date_time_new_from_g_date_time (g_date_time_new_now_utc ());
 562 }
 563 
 564 gint
 565 __gst_date_time_compare (const GstDateTime * dt1, const GstDateTime * dt2)
 566 {
 567   gint64 diff;
 568 
 569   /* we assume here that GST_DATE_TIME_FIELDS_YMD_HMS is the highest
 570    * resolution, and ignore microsecond differences on purpose for now */
 571   if (dt1->fields != dt2->fields)
 572     return GST_VALUE_UNORDERED;
 573 
 574   /* This will round down to nearest second, which is what we want. We're
 575    * not comparing microseconds on purpose here, since we're not
 576    * serialising them when doing new_utc_now() + to_string() */
 577   diff =
 578       g_date_time_to_unix (dt1->datetime) - g_date_time_to_unix (dt2->datetime);
 579   if (diff < 0)
 580     return GST_VALUE_LESS_THAN;
 581   else if (diff > 0)
 582     return GST_VALUE_GREATER_THAN;
 583   else
 584     return GST_VALUE_EQUAL;
 585 }
 586 
 587 /**
 588  * gst_date_time_new:
 589  * @tzoffset: Offset from UTC in hours.
 590  * @year: the gregorian year
 591  * @month: the gregorian month
 592  * @day: the day of the gregorian month
 593  * @hour: the hour of the day
 594  * @minute: the minute of the hour
 595  * @seconds: the second of the minute
 596  *
 597  * Creates a new #GstDateTime using the date and times in the gregorian calendar
 598  * in the supplied timezone.
 599  *
 600  * @year should be from 1 to 9999, @month should be from 1 to 12, @day from
 601  * 1 to 31, @hour from 0 to 23, @minutes and @seconds from 0 to 59.
 602  *
 603  * Note that @tzoffset is a float and was chosen so for being able to handle
 604  * some fractional timezones, while it still keeps the readability of
 605  * representing it in hours for most timezones.
 606  *
 607  * If value is -1 then all over value will be ignored. For example
 608  * if @month == -1, then #GstDateTime will created only for @year. If
 609  * @day == -1, then #GstDateTime will created for @year and @month and
 610  * so on.
 611  *
 612  * Free-function: gst_date_time_unref
 613  *
 614  * Return value: (transfer full): the newly created #GstDateTime
 615  */
 616 GstDateTime *
 617 gst_date_time_new (gfloat tzoffset, gint year, gint month, gint day, gint hour,
 618     gint minute, gdouble seconds)
 619 {
 620   GstDateTimeFields fields;
 621   gchar buf[6];
 622   GTimeZone *tz;
 623   GDateTime *dt;
 624   GstDateTime *datetime;
 625   gint tzhour, tzminute;
 626 
 627   g_return_val_if_fail (year > 0 && year <= 9999, NULL);
 628   g_return_val_if_fail ((month > 0 && month <= 12) || month == -1, NULL);
 629   g_return_val_if_fail ((day > 0 && day <= 31) || day == -1, NULL);
 630   g_return_val_if_fail ((hour >= 0 && hour < 24) || hour == -1, NULL);
 631   g_return_val_if_fail ((minute >= 0 && minute < 60) || minute == -1, NULL);
 632   g_return_val_if_fail ((seconds >= 0 && seconds < 60) || seconds == -1, NULL);
 633   g_return_val_if_fail (tzoffset >= -12.0 && tzoffset <= 12.0, NULL);
 634   g_return_val_if_fail ((hour >= 0 && minute >= 0) ||
 635       (hour == -1 && minute == -1 && seconds == -1 && tzoffset == 0.0), NULL);
 636 
 637   tzhour = (gint) ABS (tzoffset);
 638   tzminute = (gint) ((ABS (tzoffset) - tzhour) * 60);
 639 
 640   g_snprintf (buf, 6, "%c%02d%02d", tzoffset >= 0 ? '+' : '-', tzhour,
 641       tzminute);
 642 
 643   tz = g_time_zone_new (buf);
 644 
 645   fields = gst_date_time_check_fields (&year, &month, &day,
 646       &hour, &minute, &seconds);
 647 
 648   dt = g_date_time_new (tz, year, month, day, hour, minute, seconds);
 649   g_time_zone_unref (tz);
 650 
 651   datetime = gst_date_time_new_from_g_date_time (dt);
 652 #ifdef GSTREAMER_LITE
 653   if (datetime == NULL)
 654     return NULL;
 655 #endif // GSTREAMER_LITE
 656   datetime->fields = fields;
 657 
 658   return datetime;
 659 }
 660 
 661 gchar *
 662 __gst_date_time_serialize (GstDateTime * datetime, gboolean serialize_usecs)
 663 {
 664   GString *s;
 665   gfloat gmt_offset;
 666   guint msecs;
 667 
 668   /* we always have at least the year */
 669   s = g_string_new (NULL);
 670   g_string_append_printf (s, "%04u", gst_date_time_get_year (datetime));
 671 
 672   if (datetime->fields == GST_DATE_TIME_FIELDS_Y)
 673     goto done;
 674 
 675   /* add month */
 676   g_string_append_printf (s, "-%02u", gst_date_time_get_month (datetime));
 677 
 678   if (datetime->fields == GST_DATE_TIME_FIELDS_YM)
 679     goto done;
 680 
 681   /* add day of month */
 682   g_string_append_printf (s, "-%02u", gst_date_time_get_day (datetime));
 683 
 684   if (datetime->fields == GST_DATE_TIME_FIELDS_YMD)
 685     goto done;
 686 
 687   /* add time */
 688   g_string_append_printf (s, "T%02u:%02u", gst_date_time_get_hour (datetime),
 689       gst_date_time_get_minute (datetime));
 690 
 691   if (datetime->fields == GST_DATE_TIME_FIELDS_YMD_HM)
 692     goto add_timezone;
 693 
 694   /* add seconds */
 695   g_string_append_printf (s, ":%02u", gst_date_time_get_second (datetime));
 696 
 697   /* add microseconds */
 698   if (serialize_usecs) {
 699     msecs = gst_date_time_get_microsecond (datetime);
 700     if (msecs != 0) {
 701       g_string_append_printf (s, ".%06u", msecs);
 702       /* trim trailing 0s */
 703       while (s->str[s->len - 1] == '0')
 704         g_string_truncate (s, s->len - 1);
 705     }
 706   }
 707 
 708   /* add timezone */
 709 
 710 add_timezone:
 711 
 712   gmt_offset = gst_date_time_get_time_zone_offset (datetime);
 713   if (gmt_offset == 0) {
 714     g_string_append_c (s, 'Z');
 715   } else {
 716     guint tzhour, tzminute;
 717 
 718     tzhour = (guint) ABS (gmt_offset);
 719     tzminute = (guint) ((ABS (gmt_offset) - tzhour) * 60);
 720 
 721     g_string_append_c (s, (gmt_offset >= 0) ? '+' : '-');
 722     g_string_append_printf (s, "%02u%02u", tzhour, tzminute);
 723   }
 724 
 725 done:
 726 
 727   return g_string_free (s, FALSE);
 728 }
 729 
 730 /**
 731  * gst_date_time_to_iso8601_string:
 732  * @datetime: GstDateTime.
 733  *
 734  * Create a minimal string compatible with ISO-8601. Possible output formats
 735  * are (for example): 2012, 2012-06, 2012-06-23, 2012-06-23T23:30Z,
 736  * 2012-06-23T23:30+0100, 2012-06-23T23:30:59Z, 2012-06-23T23:30:59+0100
 737  *
 738  * Returns: (nullable): a newly allocated string formatted according
 739  *     to ISO 8601 and only including the datetime fields that are
 740  *     valid, or %NULL in case there was an error. The string should
 741  *     be freed with g_free().
 742  */
 743 gchar *
 744 gst_date_time_to_iso8601_string (GstDateTime * datetime)
 745 {
 746   g_return_val_if_fail (datetime != NULL, NULL);
 747 
 748   if (datetime->fields == GST_DATE_TIME_FIELDS_INVALID)
 749     return NULL;
 750 
 751   return __gst_date_time_serialize (datetime, FALSE);
 752 }
 753 
 754 /**
 755  * gst_date_time_new_from_iso8601_string:
 756  * @string: ISO 8601-formatted datetime string.
 757  *
 758  * Tries to parse common variants of ISO-8601 datetime strings into a
 759  * #GstDateTime.
 760  *
 761  * Free-function: gst_date_time_unref
 762  *
 763  * Returns: (transfer full) (nullable): a newly created #GstDateTime,
 764  * or %NULL on error
 765  */
 766 GstDateTime *
 767 gst_date_time_new_from_iso8601_string (const gchar * string)
 768 {
 769   gint year = -1, month = -1, day = -1, hour = -1, minute = -1;
 770   gdouble second = -1.0;
 771   gfloat tzoffset = 0.0;
 772   guint64 usecs;
 773   gint len, ret;
 774 
 775   g_return_val_if_fail (string != NULL, NULL);
 776 
 777   GST_DEBUG ("Parsing '%s' into a datetime", string);
 778 
 779   len = strlen (string);
 780 
 781   if (len < 4 || !g_ascii_isdigit (string[0]) || !g_ascii_isdigit (string[1])
 782       || !g_ascii_isdigit (string[2]) || !g_ascii_isdigit (string[3]))
 783     return NULL;
 784 
 785   ret = sscanf (string, "%04d-%02d-%02d", &year, &month, &day);
 786 
 787   if (ret == 0)
 788     return NULL;
 789 
 790   if (ret == 3 && day <= 0) {
 791     ret = 2;
 792     day = -1;
 793   }
 794 
 795   if (ret >= 2 && month <= 0) {
 796     ret = 1;
 797     month = day = -1;
 798   }
 799 
 800   if (ret >= 1 && year <= 0)
 801     return NULL;
 802 
 803   else if (ret >= 1 && len < 16)
 804     /* YMD is 10 chars. XMD + HM will be 16 chars. if it is less,
 805      * it make no sense to continue. We will stay with YMD. */
 806     goto ymd;
 807 
 808   string += 10;
 809   /* Exit if there is no expeceted value on this stage */
 810   if (!(*string == 'T' || *string == '-' || *string == ' '))
 811     goto ymd;
 812 
 813   /* if hour or minute fails, then we will use onlly ymd. */
 814   hour = g_ascii_strtoull (string + 1, (gchar **) & string, 10);
 815   if (hour > 24 || *string != ':')
 816     goto ymd;
 817 
 818   /* minute */
 819   minute = g_ascii_strtoull (string + 1, (gchar **) & string, 10);
 820   if (minute > 59)
 821     goto ymd;
 822 
 823   /* second */
 824   if (*string == ':') {
 825     second = g_ascii_strtoull (string + 1, (gchar **) & string, 10);
 826     /* if we fail here, we still can reuse hour and minute. We
 827      * will still attempt to parse any timezone information */
 828     if (second > 59) {
 829       second = -1.0;
 830     } else {
 831       /* microseconds */
 832       if (*string == '.' || *string == ',') {
 833         const gchar *usec_start = string + 1;
 834         guint digits;
 835 
 836         usecs = g_ascii_strtoull (string + 1, (gchar **) & string, 10);
 837         if (usecs != G_MAXUINT64 && string > usec_start) {
 838           digits = (guint) (string - usec_start);
 839           second += (gdouble) usecs / pow (10.0, digits);
 840         }
 841       }
 842     }
 843   }
 844 
 845   if (*string == 'Z')
 846     goto ymd_hms;
 847   else {
 848     /* reuse some code from gst-plugins-base/gst-libs/gst/tag/gstxmptag.c */
 849     gint gmt_offset_hour = -1, gmt_offset_min = -1, gmt_offset = -1;
 850     gchar *plus_pos = NULL;
 851     gchar *neg_pos = NULL;
 852     gchar *pos = NULL;
 853 
 854     GST_LOG ("Checking for timezone information");
 855 
 856     /* check if there is timezone info */
 857     plus_pos = strrchr (string, '+');
 858     neg_pos = strrchr (string, '-');
 859     if (plus_pos)
 860       pos = plus_pos + 1;
 861     else if (neg_pos)
 862       pos = neg_pos + 1;
 863 
 864     if (pos) {
 865       gint ret_tz;
 866       if (pos[2] == ':')
 867         ret_tz = sscanf (pos, "%d:%d", &gmt_offset_hour, &gmt_offset_min);
 868       else
 869         ret_tz = sscanf (pos, "%02d%02d", &gmt_offset_hour, &gmt_offset_min);
 870 
 871       GST_DEBUG ("Parsing timezone: %s", pos);
 872 
 873       if (ret_tz == 2) {
 874         gmt_offset = gmt_offset_hour * 60 + gmt_offset_min;
 875         if (neg_pos != NULL && neg_pos + 1 == pos)
 876           gmt_offset *= -1;
 877 
 878         tzoffset = gmt_offset / 60.0;
 879 
 880         GST_LOG ("Timezone offset: %f (%d minutes)", tzoffset, gmt_offset);
 881       } else
 882         GST_WARNING ("Failed to parse timezone information");
 883     }
 884   }
 885 
 886 ymd_hms:
 887   return gst_date_time_new (tzoffset, year, month, day, hour, minute, second);
 888 ymd:
 889   return gst_date_time_new_ymd (year, month, day);
 890 }
 891 
 892 static void
 893 gst_date_time_free (GstDateTime * datetime)
 894 {
 895   g_date_time_unref (datetime->datetime);
 896   g_slice_free (GstDateTime, datetime);
 897 }
 898 
 899 /**
 900  * gst_date_time_ref:
 901  * @datetime: a #GstDateTime
 902  *
 903  * Atomically increments the reference count of @datetime by one.
 904  *
 905  * Return value: (transfer full): the reference @datetime
 906  */
 907 GstDateTime *
 908 gst_date_time_ref (GstDateTime * datetime)
 909 {
 910   return (GstDateTime *) gst_mini_object_ref (GST_MINI_OBJECT_CAST (datetime));
 911 }
 912 
 913 /**
 914  * gst_date_time_unref:
 915  * @datetime: (transfer full): a #GstDateTime
 916  *
 917  * Atomically decrements the reference count of @datetime by one.  When the
 918  * reference count reaches zero, the structure is freed.
 919  */
 920 void
 921 gst_date_time_unref (GstDateTime * datetime)
 922 {
 923   gst_mini_object_unref (GST_MINI_OBJECT_CAST (datetime));
 924 }
 925 
 926 void
 927 _priv_gst_date_time_initialize (void)
 928 {
 929   _gst_date_time_type = gst_date_time_get_type ();
 930 }