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gdatetime: Use proleptic gregorian
Use Proleptic Gregorian calendar instead of the Julian calendar as the internal representation. https://bugzilla.gnome.org/show_bug.cgi?id=50076 Signed-off-by: Emmanuele Bassi <ebassi@linux.intel.com>
This commit is contained in:
Thiago Santos
Emmanuele Bassi
parent
6bb89501cf
commit
875ad12345
225
glib/gdatetime.c
225
glib/gdatetime.c
@ -76,18 +76,25 @@
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* reference count drops to 0, the resources allocated by the #GDateTime
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* structure are released.
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*
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* Internally, #GDateTime uses the Julian Day Number since the
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* initial Julian Period (-4712 BC). However, the public API uses the
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* Internally, #GDateTime uses the Proleptic Gregorian Calendar, the first
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* representable date is 0001-01-01. However, the public API uses the
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* internationally accepted Gregorian Calendar.
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*
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* #GDateTime is available since GLib 2.26.
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*/
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#define UNIX_EPOCH_START 719163
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#define DAYS_IN_4YEARS 1461 /* days in 4 years */
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#define DAYS_IN_100YEARS 36524 /* days in 100 years */
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#define DAYS_IN_400YEARS 146097 /* days in 400 years */
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#define USEC_PER_SECOND (G_GINT64_CONSTANT (1000000))
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#define USEC_PER_MINUTE (G_GINT64_CONSTANT (60000000))
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#define USEC_PER_HOUR (G_GINT64_CONSTANT (3600000000))
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#define USEC_PER_MILLISECOND (G_GINT64_CONSTANT (1000))
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#define USEC_PER_DAY (G_GINT64_CONSTANT (86400000000))
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#define SEC_PER_DAY (G_GINT64_CONSTANT (86400))
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#define GREGORIAN_LEAP(y) ((((y) % 4) == 0) && (!((((y) % 100) == 0) && (((y) % 400) != 0))))
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#define JULIAN_YEAR(d) ((d)->julian / 365.25)
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@ -113,16 +120,10 @@ typedef struct _GTimeZone GTimeZone;
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struct _GDateTime
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{
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/* Julian Period, 0 is Initial Epoch */
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gint period : 3;
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/* Day within Julian Period */
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guint julian : 22;
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/* 1 is 0001-01-01 in Proleptic Gregorian */
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guint32 days;
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/* Microsecond timekeeping within Day */
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guint64 usec : 37;
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gint reserved : 2;
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guint64 usec;
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/* TimeZone information, NULL is UTC */
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GTimeZone *tz;
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@ -281,40 +282,29 @@ get_weekday_name_abbr (gint day)
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}
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static inline gint
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date_to_julian (gint year,
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date_to_proleptic_gregorian (gint year,
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gint month,
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gint day)
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{
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gint a = (14 - month) / 12;
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gint y = year + 4800 - a;
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gint m = month + (12 * a) - 3;
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gint64 days;
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return day
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+ (((153 * m) + 2) / 5)
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+ (y * 365)
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+ (y / 4)
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- (y / 100)
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+ (y / 400)
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- 32045;
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days = (year - 1) * 365 + ((year - 1) / 4) - ((year - 1) / 100)
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+ ((year - 1) / 400);
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days += days_in_year[0][month - 1];
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if (GREGORIAN_LEAP (year) && month > 2)
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day++;
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days += day;
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return days;
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}
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static inline void
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g_date_time_add_days_internal (GDateTime *datetime,
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gint64 days)
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{
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gint __day = datetime->julian + days;
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if (__day < 1)
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{
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datetime->period += -1 + (__day / DAYS_PER_PERIOD);
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datetime->period += DAYS_PER_PERIOD + (__day % DAYS_PER_PERIOD);
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}
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else if (__day > DAYS_PER_PERIOD)
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{
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datetime->period += (datetime->julian + days) / DAYS_PER_PERIOD;
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datetime->julian = (datetime->julian + days) % DAYS_PER_PERIOD;
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}
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else
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datetime->julian += days;
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datetime->days += days;
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}
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static inline void
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@ -392,10 +382,7 @@ g_date_time_add_ymd (GDateTime *datetime,
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if (max_days[m] < d)
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d = max_days[m];
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/* since the add_days_internal() uses the julian date we need to
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* update it using the new year/month/day and then add the days
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*/
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datetime->julian = date_to_julian (y, m, d);
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datetime->days = date_to_proleptic_gregorian (y, m, d);
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g_date_time_add_days_internal (datetime, days);
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}
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@ -1052,15 +1039,13 @@ g_date_time_compare (gconstpointer dt1,
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a = dt1;
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b = dt2;
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if ((a->period == b->period) &&
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(a->julian == b->julian) &&
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if ((a->days == b->days )&&
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(a->usec == b->usec))
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{
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return 0;
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}
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else if ((a->period > b->period) ||
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((a->period == b->period) && (a->julian > b->julian)) ||
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((a->period == b->period) && (a->julian == b->julian) && a->usec > b->usec))
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else if ((a->days > b->days) ||
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((a->days == b->days) && a->usec > b->usec))
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{
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return 1;
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}
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@ -1087,8 +1072,7 @@ g_date_time_copy (const GDateTime *datetime)
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g_return_val_if_fail (datetime != NULL, NULL);
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copied = g_date_time_new ();
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copied->period = datetime->period;
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copied->julian = datetime->julian;
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copied->days = datetime->days;
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copied->usec = datetime->usec;
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copied->tz = g_time_zone_copy (datetime->tz);
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@ -1141,13 +1125,8 @@ g_date_time_difference (const GDateTime *begin,
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g_return_val_if_fail (begin != NULL, 0);
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g_return_val_if_fail (end != NULL, 0);
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if (begin->period != 0 || end->period != 0)
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{
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g_warning ("GDateTime only supports the current Julian period");
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return 0;
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}
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return ((end->julian - begin->julian) * USEC_PER_DAY) + (end->usec - begin->usec);
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return (GTimeSpan) (((gint64) end->days - (gint64) begin->days)
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* USEC_PER_DAY) + ((gint64) end->usec - (gint64) begin->usec);
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}
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/**
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@ -1298,23 +1277,81 @@ g_date_time_get_dmy (const GDateTime *datetime,
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gint *month,
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gint *year)
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{
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gint a, b, c, d, e, m;
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gint the_year;
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gint the_month;
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gint the_day;
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gint remaining_days;
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gint y100_cycles;
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gint y4_cycles;
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gint y1_cycles;
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gint preceding;
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gboolean leap;
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a = datetime->julian + 32044;
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b = ((4 * a) + 3) / 146097;
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c = a - ((b * 146097) / 4);
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d = ((4 * c) + 3) / 1461;
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e = c - (1461 * d) / 4;
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m = (5 * e + 2) / 153;
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g_return_if_fail (datetime != NULL);
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if (day != NULL)
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*day = e - (((153 * m) + 2) / 5) + 1;
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remaining_days = datetime->days;
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if (month != NULL)
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*month = m + 3 - (12 * (m / 10));
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/*
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* We need to convert an offset in days to its year/month/day representation.
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* Leap years makes this a little trickier than it should be, so we use
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* 400, 100 and 4 years cycles here to get to the correct year.
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*/
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if (year != NULL)
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*year = (b * 100) + d - 4800 + (m / 10);
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/* Our days offset starts sets 0001-01-01 as day 1, if it was day 0 our
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* math would be simpler, so let's do it */
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remaining_days--;
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the_year = (remaining_days / DAYS_IN_400YEARS) * 400 + 1;
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remaining_days = remaining_days % DAYS_IN_400YEARS;
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y100_cycles = remaining_days / DAYS_IN_100YEARS;
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remaining_days = remaining_days % DAYS_IN_100YEARS;
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the_year += y100_cycles * 100;
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y4_cycles = remaining_days / DAYS_IN_4YEARS;
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remaining_days = remaining_days % DAYS_IN_4YEARS;
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the_year += y4_cycles * 4;
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y1_cycles = remaining_days / 365;
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the_year += y1_cycles;
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remaining_days = remaining_days % 365;
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if (y1_cycles == 4 || y100_cycles == 4) {
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g_assert (remaining_days == 0);
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/* special case that indicates that the date is actually one year before,
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* in the 31th of December */
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the_year--;
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the_month = 12;
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the_day = 31;
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goto end;
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}
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/* now get the month and the day */
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leap = y1_cycles == 3 && (y4_cycles != 24 || y100_cycles == 3);
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g_assert (leap == GREGORIAN_LEAP(the_year));
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the_month = (remaining_days + 50) >> 5;
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preceding = (days_in_year[0][the_month - 1] + (the_month > 2 && leap));
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if (preceding > remaining_days) {
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/* estimate is too large */
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the_month -= 1;
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preceding -= leap ? days_in_months[1][the_month] :
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days_in_months[0][the_month];
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}
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remaining_days -= preceding;
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g_assert(0 <= remaining_days);
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the_day = remaining_days + 1;
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end:
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if (year)
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*year = the_year;
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if (month)
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*month = the_month;
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if (day)
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*day = the_day;
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}
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/**
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@ -1357,13 +1394,26 @@ g_date_time_get_julian (const GDateTime *datetime,
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gint *minute,
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gint *second)
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{
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gint y, m, d, a, b, c, e, f, j;
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g_return_if_fail (datetime != NULL);
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g_date_time_get_dmy (datetime, &d, &m, &y);
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/* FIXME: This is probably not optimal and doesn't handle the fact that the
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* julian calendar has its 0 hour on midday */
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a = y / 100;
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b = a / 4;
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c = 2 - a + b;
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e = 365.25 * (y + 4716);
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f = 30.6001 * (m + 1);
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j = c + d + e + f - 1524;
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if (period)
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*period = datetime->period;
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*period = 0;
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if (julian)
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*julian = datetime->julian;
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*julian = j;
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if (hour)
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*hour = (datetime->usec / USEC_PER_HOUR);
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@ -1630,7 +1680,8 @@ g_date_time_new_from_date (gint year,
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g_return_val_if_fail (day > 0 && day <= 31, NULL);
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dt = g_date_time_new ();
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dt->julian = date_to_julian (year, month, day);
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dt->days = date_to_proleptic_gregorian (year, month, day);
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dt->tz = g_date_time_create_time_zone (dt, NULL);
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return dt;
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@ -2104,33 +2155,18 @@ g_date_time_to_local (const GDateTime *datetime)
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gint64
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g_date_time_to_epoch (const GDateTime *datetime)
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{
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struct tm tm;
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gint year,
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month,
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day;
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gint64 result;
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g_return_val_if_fail (datetime != NULL, 0);
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g_return_val_if_fail (datetime->period == 0, 0);
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g_date_time_get_dmy (datetime, &day, &month, &year);
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if (datetime->days <= 0)
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return G_MININT64;
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/* FIXME we use gint64, we shold expand these limits */
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if (year < 1970)
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return 0;
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else if (year > 2037)
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return G_MAXINT64;
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result = (datetime->days - UNIX_EPOCH_START) * SEC_PER_DAY
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+ datetime->usec / USEC_PER_SECOND
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- g_date_time_get_utc_offset (datetime) / 1000000;
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memset (&tm, 0, sizeof (tm));
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tm.tm_year = year - 1900;
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tm.tm_mon = month - 1;
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tm.tm_mday = day;
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tm.tm_hour = g_date_time_get_hour (datetime);
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tm.tm_min = g_date_time_get_minute (datetime);
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tm.tm_sec = g_date_time_get_second (datetime);
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tm.tm_isdst = -1;
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return (gint64) mktime (&tm);
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return result;
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}
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/**
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@ -2151,11 +2187,8 @@ g_date_time_to_timeval (const GDateTime *datetime,
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tv->tv_sec = 0;
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tv->tv_usec = 0;
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if (G_LIKELY (datetime->period == 0))
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{
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tv->tv_sec = g_date_time_to_epoch (datetime);
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tv->tv_usec = datetime->usec % USEC_PER_SECOND;
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}
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tv->tv_sec = g_date_time_to_epoch (datetime);
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tv->tv_usec = datetime->usec % USEC_PER_SECOND;
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}
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/**
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@ -293,6 +293,9 @@ test_GDateTime_get_dmy (void)
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struct tm tm;
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time_t t;
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gint d, m, y;
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gint d2, m2, y2;
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gint days[2][13] = {{0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
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{0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}};
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t = time (NULL);
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memset (&tm, 0, sizeof (struct tm));
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@ -303,6 +306,28 @@ test_GDateTime_get_dmy (void)
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g_assert_cmpint(y, ==, tm.tm_year + 1900);
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g_assert_cmpint(m, ==, tm.tm_mon + 1);
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g_assert_cmpint(d, ==, tm.tm_mday);
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/* exaustive test */
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for (y = 1750; y < 2250; y++)
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{
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gint leap = ((y % 4) == 0) && (!(((y % 100) == 0) && ((y % 400) != 0)))
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? 1
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: 0;
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for (m = 1; m <= 12; m++)
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{
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for (d = 1; d <= days[leap][m]; d++)
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{
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GDateTime *dt1 = g_date_time_new_from_date (y, m, d);
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g_date_time_get_dmy (dt1, &d2, &m2, &y2);
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g_assert_cmpint (y, ==, y2);
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g_assert_cmpint (m, ==, m2);
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g_assert_cmpint (d, ==, d2);
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g_date_time_unref (dt1);
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}
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}
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}
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}
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static void
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@ -410,6 +435,13 @@ test_GDateTime_new_from_timeval (void)
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g_get_current_time (&tv);
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dt = g_date_time_new_from_timeval (&tv);
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if (g_test_verbose ())
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g_print ("\nDT%d/%d/%d\n",
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g_date_time_get_year (dt),
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g_date_time_get_month (dt),
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g_date_time_get_day_of_month (dt));
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g_date_time_to_timeval (dt, &tv2);
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g_assert_cmpint (tv.tv_sec, ==, tv2.tv_sec);
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g_assert_cmpint (tv.tv_usec, ==, tv2.tv_usec);
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