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Diffstat (limited to 'glib-1.2.10/gdate.c')
| -rw-r--r-- | glib-1.2.10/gdate.c | 1294 |
1 files changed, 1294 insertions, 0 deletions
diff --git a/glib-1.2.10/gdate.c b/glib-1.2.10/gdate.c new file mode 100644 index 0000000..b278a5a --- /dev/null +++ b/glib-1.2.10/gdate.c @@ -0,0 +1,1294 @@ +/* GLIB - Library of useful routines for C programming + * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald + * + * This library is free software; you can redistribute it and/or + * modify it under the terms of the GNU Library General Public + * License as published by the Free Software Foundation; either + * version 2 of the License, or (at your option) any later version. + * + * This library is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * Library General Public License for more details. + * + * You should have received a copy of the GNU Library General Public + * License along with this library; if not, write to the + * Free Software Foundation, Inc., 59 Temple Place - Suite 330, + * Boston, MA 02111-1307, USA. + */ + +/* + * Modified by the GLib Team and others 1997-1999. See the AUTHORS + * file for a list of people on the GLib Team. See the ChangeLog + * files for a list of changes. These files are distributed with + * GLib at ftp://ftp.gtk.org/pub/gtk/. + */ + +/* + * MT safe + */ + +#ifdef HAVE_CONFIG_H +#include <config.h> +#endif + +#include "glib.h" + +#include <time.h> +#include <string.h> +#include <ctype.h> +#include <stdlib.h> +#include <locale.h> + +GDate* +g_date_new () +{ + GDate *d = g_new0 (GDate, 1); /* happily, 0 is the invalid flag for everything. */ + + return d; +} + +GDate* +g_date_new_dmy (GDateDay day, GDateMonth m, GDateYear y) +{ + GDate *d; + g_return_val_if_fail (g_date_valid_dmy (day, m, y), NULL); + + d = g_new (GDate, 1); + + d->julian = FALSE; + d->dmy = TRUE; + + d->month = m; + d->day = day; + d->year = y; + + g_assert (g_date_valid (d)); + + return d; +} + +GDate* +g_date_new_julian (guint32 j) +{ + GDate *d; + g_return_val_if_fail (g_date_valid_julian (j), NULL); + + d = g_new (GDate, 1); + + d->julian = TRUE; + d->dmy = FALSE; + + d->julian_days = j; + + g_assert (g_date_valid (d)); + + return d; +} + +void +g_date_free (GDate *d) +{ + g_return_if_fail (d != NULL); + + g_free (d); +} + +gboolean +g_date_valid (GDate *d) +{ + g_return_val_if_fail (d != NULL, FALSE); + + return (d->julian || d->dmy); +} + +static const guint8 days_in_months[2][13] = +{ /* error, jan feb mar apr may jun jul aug sep oct nov dec */ + { 0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 }, + { 0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31 } /* leap year */ +}; + +static const guint16 days_in_year[2][14] = +{ /* 0, jan feb mar apr may jun jul aug sep oct nov dec */ + { 0, 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334, 365 }, + { 0, 0, 31, 60, 91, 121, 152, 182, 213, 244, 274, 305, 335, 366 } +}; + +gboolean +g_date_valid_month (GDateMonth m) +{ + return ( (m > G_DATE_BAD_MONTH) && (m < 13) ); +} + +gboolean +g_date_valid_year (GDateYear y) +{ + return ( y > G_DATE_BAD_YEAR ); +} + +gboolean +g_date_valid_day (GDateDay d) +{ + return ( (d > G_DATE_BAD_DAY) && (d < 32) ); +} + +gboolean +g_date_valid_weekday (GDateWeekday w) +{ + return ( (w > G_DATE_BAD_WEEKDAY) && (w < 8) ); +} + +gboolean +g_date_valid_julian (guint32 j) +{ + return (j > G_DATE_BAD_JULIAN); +} + +gboolean +g_date_valid_dmy (GDateDay d, + GDateMonth m, + GDateYear y) +{ + return ( (m > G_DATE_BAD_MONTH) && + (m < 13) && + (d > G_DATE_BAD_DAY) && + (y > G_DATE_BAD_YEAR) && /* must check before using g_date_is_leap_year */ + (d <= (g_date_is_leap_year (y) ? + days_in_months[1][m] : days_in_months[0][m])) ); +} + + +/* "Julian days" just means an absolute number of days, where Day 1 == + * Jan 1, Year 1 + */ +static void +g_date_update_julian (GDate *d) +{ + GDateYear year; + gint index; + + g_return_if_fail (d != NULL); + g_return_if_fail (d->dmy); + g_return_if_fail (!d->julian); + g_return_if_fail (g_date_valid_dmy (d->day, d->month, d->year)); + + /* What we actually do is: multiply years * 365 days in the year, + * add the number of years divided by 4, subtract the number of + * years divided by 100 and add the number of years divided by 400, + * which accounts for leap year stuff. Code from Steffen Beyer's + * DateCalc. + */ + + year = d->year - 1; /* we know d->year > 0 since it's valid */ + + d->julian_days = year * 365U; + d->julian_days += (year >>= 2); /* divide by 4 and add */ + d->julian_days -= (year /= 25); /* divides original # years by 100 */ + d->julian_days += year >> 2; /* divides by 4, which divides original by 400 */ + + index = g_date_is_leap_year (d->year) ? 1 : 0; + + d->julian_days += days_in_year[index][d->month] + d->day; + + g_return_if_fail (g_date_valid_julian (d->julian_days)); + + d->julian = TRUE; +} + +static void +g_date_update_dmy (GDate *d) +{ + GDateYear y; + GDateMonth m; + GDateDay day; + + guint32 A, B, C, D, E, M; + + g_return_if_fail (d != NULL); + g_return_if_fail (d->julian); + g_return_if_fail (!d->dmy); + g_return_if_fail (g_date_valid_julian (d->julian_days)); + + /* Formula taken from the Calendar FAQ; the formula was for the + * Julian Period which starts on 1 January 4713 BC, so we add + * 1,721,425 to the number of days before doing the formula. + * + * I'm sure this can be simplified for our 1 January 1 AD period + * start, but I can't figure out how to unpack the formula. + */ + + A = d->julian_days + 1721425 + 32045; + B = ( 4 *(A + 36524) )/ 146097 - 1; + C = A - (146097 * B)/4; + D = ( 4 * (C + 365) ) / 1461 - 1; + E = C - ((1461*D) / 4); + M = (5 * (E - 1) + 2)/153; + + m = M + 3 - (12*(M/10)); + day = E - (153*M + 2)/5; + y = 100 * B + D - 4800 + (M/10); + +#ifdef G_ENABLE_DEBUG + if (!g_date_valid_dmy (day, m, y)) + { + g_warning ("\nOOPS julian: %u computed dmy: %u %u %u\n", + d->julian_days, day, m, y); + } +#endif + + d->month = m; + d->day = day; + d->year = y; + + d->dmy = TRUE; +} + +GDateWeekday +g_date_weekday (GDate *d) +{ + g_return_val_if_fail (d != NULL, G_DATE_BAD_WEEKDAY); + g_return_val_if_fail (g_date_valid (d), G_DATE_BAD_WEEKDAY); + + if (!d->julian) + { + g_date_update_julian (d); + } + g_return_val_if_fail (d->julian, G_DATE_BAD_WEEKDAY); + + return ((d->julian_days - 1) % 7) + 1; +} + +GDateMonth +g_date_month (GDate *d) +{ + g_return_val_if_fail (d != NULL, G_DATE_BAD_MONTH); + g_return_val_if_fail (g_date_valid (d), G_DATE_BAD_MONTH); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_val_if_fail (d->dmy, G_DATE_BAD_MONTH); + + return d->month; +} + +GDateYear +g_date_year (GDate *d) +{ + g_return_val_if_fail (d != NULL, G_DATE_BAD_YEAR); + g_return_val_if_fail (g_date_valid (d), G_DATE_BAD_YEAR); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_val_if_fail (d->dmy, G_DATE_BAD_YEAR); + + return d->year; +} + +GDateDay +g_date_day (GDate *d) +{ + g_return_val_if_fail (d != NULL, G_DATE_BAD_DAY); + g_return_val_if_fail (g_date_valid (d), G_DATE_BAD_DAY); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_val_if_fail (d->dmy, G_DATE_BAD_DAY); + + return d->day; +} + +guint32 +g_date_julian (GDate *d) +{ + g_return_val_if_fail (d != NULL, G_DATE_BAD_JULIAN); + g_return_val_if_fail (g_date_valid (d), G_DATE_BAD_JULIAN); + + if (!d->julian) + { + g_date_update_julian (d); + } + g_return_val_if_fail (d->julian, G_DATE_BAD_JULIAN); + + return d->julian_days; +} + +guint +g_date_day_of_year (GDate *d) +{ + gint index; + + g_return_val_if_fail (d != NULL, 0); + g_return_val_if_fail (g_date_valid (d), 0); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_val_if_fail (d->dmy, 0); + + index = g_date_is_leap_year (d->year) ? 1 : 0; + + return (days_in_year[index][d->month] + d->day); +} + +guint +g_date_monday_week_of_year (GDate *d) +{ + GDateWeekday wd; + guint day; + GDate first; + + g_return_val_if_fail (d != NULL, 0); + g_return_val_if_fail (g_date_valid (d), 0); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_val_if_fail (d->dmy, 0); + + g_date_clear (&first, 1); + + g_date_set_dmy (&first, 1, 1, d->year); + + wd = g_date_weekday (&first) - 1; /* make Monday day 0 */ + day = g_date_day_of_year (d) - 1; + + return ((day + wd)/7U + (wd == 0 ? 1 : 0)); +} + +guint +g_date_sunday_week_of_year (GDate *d) +{ + GDateWeekday wd; + guint day; + GDate first; + + g_return_val_if_fail (d != NULL, 0); + g_return_val_if_fail (g_date_valid (d), 0); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_val_if_fail (d->dmy, 0); + + g_date_clear (&first, 1); + + g_date_set_dmy (&first, 1, 1, d->year); + + wd = g_date_weekday (&first); + if (wd == 7) wd = 0; /* make Sunday day 0 */ + day = g_date_day_of_year (d) - 1; + + return ((day + wd)/7U + (wd == 0 ? 1 : 0)); +} + +void +g_date_clear (GDate *d, guint ndates) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (ndates != 0); + + memset (d, 0x0, ndates*sizeof (GDate)); +} + +G_LOCK_DEFINE_STATIC (g_date_global); + +/* These are for the parser, output to the user should use * + * g_date_strftime () - this creates more never-freed memory to annoy + * all those memory debugger users. :-) + */ + +static gchar *long_month_names[13] = +{ + "Error", NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL +}; + +static gchar *short_month_names[13] = +{ + "Error", NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL +}; + +/* This tells us if we need to update the parse info */ +static gchar *current_locale = NULL; + +/* order of these in the current locale */ +static GDateDMY dmy_order[3] = +{ + G_DATE_DAY, G_DATE_MONTH, G_DATE_YEAR +}; + +/* Where to chop two-digit years: i.e., for the 1930 default, numbers + * 29 and below are counted as in the year 2000, numbers 30 and above + * are counted as in the year 1900. + */ + +static GDateYear twodigit_start_year = 1930; + +/* It is impossible to enter a year between 1 AD and 99 AD with this + * in effect. + */ +static gboolean using_twodigit_years = FALSE; + +struct _GDateParseTokens { + gint num_ints; + gint n[3]; + guint month; +}; + +typedef struct _GDateParseTokens GDateParseTokens; + +#define NUM_LEN 10 + +/* HOLDS: g_date_global_lock */ +static void +g_date_fill_parse_tokens (const gchar *str, GDateParseTokens *pt) +{ + gchar num[4][NUM_LEN+1]; + gint i; + const guchar *s; + + /* We count 4, but store 3; so we can give an error + * if there are 4. + */ + num[0][0] = num[1][0] = num[2][0] = num[3][0] = '\0'; + + s = str; + pt->num_ints = 0; + while (*s && pt->num_ints < 4) + { + + i = 0; + while (*s && isdigit (*s) && i <= NUM_LEN) + { + num[pt->num_ints][i] = *s; + ++s; + ++i; + } + + if (i > 0) + { + num[pt->num_ints][i] = '\0'; + ++(pt->num_ints); + } + + if (*s == '\0') break; + + ++s; + } + + pt->n[0] = pt->num_ints > 0 ? atoi (num[0]) : 0; + pt->n[1] = pt->num_ints > 1 ? atoi (num[1]) : 0; + pt->n[2] = pt->num_ints > 2 ? atoi (num[2]) : 0; + + pt->month = G_DATE_BAD_MONTH; + + if (pt->num_ints < 3) + { + gchar lcstr[128]; + int i = 1; + + strncpy (lcstr, str, 127); + g_strdown (lcstr); + + while (i < 13) + { + if (long_month_names[i] != NULL) + { + const gchar *found = strstr (lcstr, long_month_names[i]); + + if (found != NULL) + { + pt->month = i; + return; + } + } + + if (short_month_names[i] != NULL) + { + const gchar *found = strstr (lcstr, short_month_names[i]); + + if (found != NULL) + { + pt->month = i; + return; + } + } + + ++i; + } + } +} + +/* HOLDS: g_date_global_lock */ +static void +g_date_prepare_to_parse (const gchar *str, GDateParseTokens *pt) +{ + const gchar *locale = setlocale (LC_TIME, NULL); + gboolean recompute_localeinfo = FALSE; + GDate d; + + g_return_if_fail (locale != NULL); /* should not happen */ + + g_date_clear (&d, 1); /* clear for scratch use */ + + if ( (current_locale == NULL) || (strcmp (locale, current_locale) != 0) ) + { + recompute_localeinfo = TRUE; /* Uh, there used to be a reason for the temporary */ + } + + if (recompute_localeinfo) + { + int i = 1; + GDateParseTokens testpt; + gchar buf[128]; + + g_free (current_locale); /* still works if current_locale == NULL */ + + current_locale = g_strdup (locale); + + while (i < 13) + { + g_date_set_dmy (&d, 1, i, 1); + + g_return_if_fail (g_date_valid (&d)); + + g_date_strftime (buf, 127, "%b", &d); + g_free (short_month_names[i]); + g_strdown (buf); + short_month_names[i] = g_strdup (buf); + + + + g_date_strftime (buf, 127, "%B", &d); + g_free (long_month_names[i]); + g_strdown (buf); + long_month_names[i] = g_strdup (buf); + + ++i; + } + + /* Determine DMY order */ + + /* had to pick a random day - don't change this, some strftimes + * are broken on some days, and this one is good so far. */ + g_date_set_dmy (&d, 4, 7, 1976); + + g_date_strftime (buf, 127, "%x", &d); + + g_date_fill_parse_tokens (buf, &testpt); + + i = 0; + while (i < testpt.num_ints) + { + switch (testpt.n[i]) + { + case 7: + dmy_order[i] = G_DATE_MONTH; + break; + case 4: + dmy_order[i] = G_DATE_DAY; + break; + case 76: + using_twodigit_years = TRUE; /* FALL THRU */ + case 1976: + dmy_order[i] = G_DATE_YEAR; + break; + default: + /* leave it unchanged */ + break; + } + ++i; + } + +#ifdef G_ENABLE_DEBUG + g_message ("**GDate prepared a new set of locale-specific parse rules."); + i = 1; + while (i < 13) + { + g_message (" %s %s", long_month_names[i], short_month_names[i]); + ++i; + } + if (using_twodigit_years) + { + g_message ("**Using twodigit years with cutoff year: %u", twodigit_start_year); + } + { + gchar *strings[3]; + i = 0; + while (i < 3) + { + switch (dmy_order[i]) + { + case G_DATE_MONTH: + strings[i] = "Month"; + break; + case G_DATE_YEAR: + strings[i] = "Year"; + break; + case G_DATE_DAY: + strings[i] = "Day"; + break; + default: + strings[i] = NULL; + break; + } + ++i; + } + g_message ("**Order: %s, %s, %s", strings[0], strings[1], strings[2]); + g_message ("**Sample date in this locale: `%s'", buf); + } +#endif + } + + g_date_fill_parse_tokens (str, pt); +} + +void +g_date_set_parse (GDate *d, + const gchar *str) +{ + GDateParseTokens pt; + guint m = G_DATE_BAD_MONTH, day = G_DATE_BAD_DAY, y = G_DATE_BAD_YEAR; + + g_return_if_fail (d != NULL); + + /* set invalid */ + g_date_clear (d, 1); + + G_LOCK (g_date_global); + + g_date_prepare_to_parse (str, &pt); + +#ifdef G_ENABLE_DEBUG + g_message ("Found %d ints, `%d' `%d' `%d' and written out month %d", + pt.num_ints, pt.n[0], pt.n[1], pt.n[2], pt.month); +#endif + + + if (pt.num_ints == 4) + { + G_UNLOCK (g_date_global); + return; /* presumably a typo; bail out. */ + } + + if (pt.num_ints > 1) + { + int i = 0; + int j = 0; + + g_assert (pt.num_ints < 4); /* i.e., it is 2 or 3 */ + + while (i < pt.num_ints && j < 3) + { + switch (dmy_order[j]) + { + case G_DATE_MONTH: + { + if (pt.num_ints == 2 && pt.month != G_DATE_BAD_MONTH) + { + m = pt.month; + ++j; /* skip months, but don't skip this number */ + continue; + } + else + m = pt.n[i]; + } + break; + case G_DATE_DAY: + { + if (pt.num_ints == 2 && pt.month == G_DATE_BAD_MONTH) + { + day = 1; + ++j; /* skip days, since we may have month/year */ + continue; + } + day = pt.n[i]; + } + break; + case G_DATE_YEAR: + { + y = pt.n[i]; + + if (using_twodigit_years && y < 100) + { + guint two = twodigit_start_year % 100; + guint century = (twodigit_start_year / 100) * 100; + + if (y < two) + century += 100; + + y += century; + } + } + break; + default: + break; + } + + ++i; + ++j; + } + + + if (pt.num_ints == 3 && !g_date_valid_dmy (day, m, y)) + { + /* Try YYYY MM DD */ + y = pt.n[0]; + m = pt.n[1]; + day = pt.n[2]; + + if (using_twodigit_years && y < 100) + y = G_DATE_BAD_YEAR; /* avoids ambiguity */ + } + } + else if (pt.num_ints == 1) + { + if (pt.month != G_DATE_BAD_MONTH) + { + /* Month name and year? */ + m = pt.month; + day = 1; + y = pt.n[0]; + } + else + { + /* Try yyyymmdd and yymmdd */ + + m = (pt.n[0]/100) % 100; + day = pt.n[0] % 100; + y = pt.n[0]/10000; + + /* FIXME move this into a separate function */ + if (using_twodigit_years && y < 100) + { + guint two = twodigit_start_year % 100; + guint century = (twodigit_start_year / 100) * 100; + + if (y < two) + century += 100; + + y += century; + } + } + } + + /* See if we got anything valid out of all this. */ + /* y < 8000 is to catch 19998 style typos; the library is OK up to 65535 or so */ + if (y < 8000 && g_date_valid_dmy (day, m, y)) + { + d->month = m; + d->day = day; + d->year = y; + d->dmy = TRUE; + } +#ifdef G_ENABLE_DEBUG + else + g_message ("Rejected DMY %u %u %u", day, m, y); +#endif + G_UNLOCK (g_date_global); +} + +void +g_date_set_time (GDate *d, + GTime time) +{ + time_t t = time; + struct tm tm; + + g_return_if_fail (d != NULL); + +#ifdef HAVE_LOCALTIME_R + localtime_r (&t, &tm); +#else + { + struct tm *ptm = localtime (&t); + g_assert (ptm); + memcpy ((void *) &tm, (void *) ptm, sizeof(struct tm)); + } +#endif + + d->julian = FALSE; + + d->month = tm.tm_mon + 1; + d->day = tm.tm_mday; + d->year = tm.tm_year + 1900; + + g_return_if_fail (g_date_valid_dmy (d->day, d->month, d->year)); + + d->dmy = TRUE; +} + +void +g_date_set_month (GDate *d, + GDateMonth m) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid_month (m)); + + if (d->julian && !d->dmy) g_date_update_dmy(d); + d->julian = FALSE; + + d->month = m; + + if (g_date_valid_dmy (d->day, d->month, d->year)) + d->dmy = TRUE; + else + d->dmy = FALSE; +} + +void +g_date_set_day (GDate *d, + GDateDay day) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid_day (day)); + + if (d->julian && !d->dmy) g_date_update_dmy(d); + d->julian = FALSE; + + d->day = day; + + if (g_date_valid_dmy (d->day, d->month, d->year)) + d->dmy = TRUE; + else + d->dmy = FALSE; +} + +void +g_date_set_year (GDate *d, + GDateYear y) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid_year (y)); + + if (d->julian && !d->dmy) g_date_update_dmy(d); + d->julian = FALSE; + + d->year = y; + + if (g_date_valid_dmy (d->day, d->month, d->year)) + d->dmy = TRUE; + else + d->dmy = FALSE; +} + +void +g_date_set_dmy (GDate *d, + GDateDay day, + GDateMonth m, + GDateYear y) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid_dmy (day, m, y)); + + d->julian = FALSE; + + d->month = m; + d->day = day; + d->year = y; + + d->dmy = TRUE; +} + +void +g_date_set_julian (GDate *d, guint32 j) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid_julian (j)); + + d->julian_days = j; + d->julian = TRUE; + d->dmy = FALSE; +} + + +gboolean +g_date_is_first_of_month (GDate *d) +{ + g_return_val_if_fail (d != NULL, FALSE); + g_return_val_if_fail (g_date_valid (d), FALSE); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_val_if_fail (d->dmy, FALSE); + + if (d->day == 1) return TRUE; + else return FALSE; +} + +gboolean +g_date_is_last_of_month (GDate *d) +{ + gint index; + + g_return_val_if_fail (d != NULL, FALSE); + g_return_val_if_fail (g_date_valid (d), FALSE); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_val_if_fail (d->dmy, FALSE); + + index = g_date_is_leap_year (d->year) ? 1 : 0; + + if (d->day == days_in_months[index][d->month]) return TRUE; + else return FALSE; +} + +void +g_date_add_days (GDate *d, guint ndays) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid (d)); + + if (!d->julian) + { + g_date_update_julian (d); + } + g_return_if_fail (d->julian); + + d->julian_days += ndays; + d->dmy = FALSE; +} + +void +g_date_subtract_days (GDate *d, guint ndays) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid (d)); + + if (!d->julian) + { + g_date_update_julian (d); + } + g_return_if_fail (d->julian); + g_return_if_fail (d->julian_days > ndays); + + d->julian_days -= ndays; + d->dmy = FALSE; +} + +void +g_date_add_months (GDate *d, + guint nmonths) +{ + guint years, months; + gint index; + + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid (d)); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_if_fail (d->dmy); + + nmonths += d->month - 1; + + years = nmonths/12; + months = nmonths%12; + + d->month = months + 1; + d->year += years; + + index = g_date_is_leap_year (d->year) ? 1 : 0; + + if (d->day > days_in_months[index][d->month]) + d->day = days_in_months[index][d->month]; + + d->julian = FALSE; + + g_return_if_fail (g_date_valid (d)); +} + +void +g_date_subtract_months (GDate *d, + guint nmonths) +{ + guint years, months; + gint index; + + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid (d)); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_if_fail (d->dmy); + + years = nmonths/12; + months = nmonths%12; + + g_return_if_fail (d->year > years); + + d->year -= years; + + if (d->month > months) d->month -= months; + else + { + months -= d->month; + d->month = 12 - months; + d->year -= 1; + } + + index = g_date_is_leap_year (d->year) ? 1 : 0; + + if (d->day > days_in_months[index][d->month]) + d->day = days_in_months[index][d->month]; + + d->julian = FALSE; + + g_return_if_fail (g_date_valid (d)); +} + +void +g_date_add_years (GDate *d, + guint nyears) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid (d)); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_if_fail (d->dmy); + + d->year += nyears; + + if (d->month == 2 && d->day == 29) + { + if (!g_date_is_leap_year (d->year)) + { + d->day = 28; + } + } + + d->julian = FALSE; +} + +void +g_date_subtract_years (GDate *d, + guint nyears) +{ + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid (d)); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_if_fail (d->dmy); + g_return_if_fail (d->year > nyears); + + d->year -= nyears; + + if (d->month == 2 && d->day == 29) + { + if (!g_date_is_leap_year (d->year)) + { + d->day = 28; + } + } + + d->julian = FALSE; +} + + +gboolean +g_date_is_leap_year (GDateYear year) +{ + g_return_val_if_fail (g_date_valid_year (year), FALSE); + + return ( (((year % 4) == 0) && ((year % 100) != 0)) || + (year % 400) == 0 ); +} + +guint8 +g_date_days_in_month (GDateMonth month, + GDateYear year) +{ + gint index; + + g_return_val_if_fail (g_date_valid_year (year), 0); + g_return_val_if_fail (g_date_valid_month (month), 0); + + index = g_date_is_leap_year (year) ? 1 : 0; + + return days_in_months[index][month]; +} + +guint8 +g_date_monday_weeks_in_year (GDateYear year) +{ + GDate d; + + g_return_val_if_fail (g_date_valid_year (year), 0); + + g_date_clear (&d, 1); + g_date_set_dmy (&d, 1, 1, year); + if (g_date_weekday (&d) == G_DATE_MONDAY) return 53; + g_date_set_dmy (&d, 31, 12, year); + if (g_date_weekday (&d) == G_DATE_MONDAY) return 53; + if (g_date_is_leap_year (year)) + { + g_date_set_dmy (&d, 2, 1, year); + if (g_date_weekday (&d) == G_DATE_MONDAY) return 53; + g_date_set_dmy (&d, 30, 12, year); + if (g_date_weekday (&d) == G_DATE_MONDAY) return 53; + } + return 52; +} + +guint8 +g_date_sunday_weeks_in_year (GDateYear year) +{ + GDate d; + + g_return_val_if_fail (g_date_valid_year (year), 0); + + g_date_clear (&d, 1); + g_date_set_dmy (&d, 1, 1, year); + if (g_date_weekday (&d) == G_DATE_SUNDAY) return 53; + g_date_set_dmy (&d, 31, 12, year); + if (g_date_weekday (&d) == G_DATE_SUNDAY) return 53; + if (g_date_is_leap_year (year)) + { + g_date_set_dmy (&d, 2, 1, year); + if (g_date_weekday (&d) == G_DATE_SUNDAY) return 53; + g_date_set_dmy (&d, 30, 12, year); + if (g_date_weekday (&d) == G_DATE_SUNDAY) return 53; + } + return 52; +} + +gint +g_date_compare (GDate *lhs, + GDate *rhs) +{ + g_return_val_if_fail (lhs != NULL, 0); + g_return_val_if_fail (rhs != NULL, 0); + g_return_val_if_fail (g_date_valid (lhs), 0); + g_return_val_if_fail (g_date_valid (rhs), 0); + + /* Remember the self-comparison case! I think it works right now. */ + + while (TRUE) + { + + if (lhs->julian && rhs->julian) + { + if (lhs->julian_days < rhs->julian_days) return -1; + else if (lhs->julian_days > rhs->julian_days) return 1; + else return 0; + } + else if (lhs->dmy && rhs->dmy) + { + if (lhs->year < rhs->year) return -1; + else if (lhs->year > rhs->year) return 1; + else + { + if (lhs->month < rhs->month) return -1; + else if (lhs->month > rhs->month) return 1; + else + { + if (lhs->day < rhs->day) return -1; + else if (lhs->day > rhs->day) return 1; + else return 0; + } + + } + + } + else + { + if (!lhs->julian) g_date_update_julian (lhs); + if (!rhs->julian) g_date_update_julian (rhs); + g_return_val_if_fail (lhs->julian, 0); + g_return_val_if_fail (rhs->julian, 0); + } + + } + return 0; /* warnings */ +} + + +void +g_date_to_struct_tm (GDate *d, + struct tm *tm) +{ + GDateWeekday day; + + g_return_if_fail (d != NULL); + g_return_if_fail (g_date_valid (d)); + g_return_if_fail (tm != NULL); + + if (!d->dmy) + { + g_date_update_dmy (d); + } + g_return_if_fail (d->dmy); + + /* zero all the irrelevant fields to be sure they're valid */ + + /* On Linux and maybe other systems, there are weird non-POSIX + * fields on the end of struct tm that choke strftime if they + * contain garbage. So we need to 0 the entire struct, not just the + * fields we know to exist. + */ + + memset (tm, 0x0, sizeof (struct tm)); + + tm->tm_mday = d->day; + tm->tm_mon = d->month - 1; /* 0-11 goes in tm */ + tm->tm_year = ((int)d->year) - 1900; /* X/Open says tm_year can be negative */ + + day = g_date_weekday (d); + if (day == 7) day = 0; /* struct tm wants days since Sunday, so Sunday is 0 */ + + tm->tm_wday = (int)day; + + tm->tm_yday = g_date_day_of_year (d) - 1; /* 0 to 365 */ + tm->tm_isdst = -1; /* -1 means "information not available" */ +} + +gsize +g_date_strftime (gchar *s, + gsize slen, + const gchar *format, + GDate *d) +{ + struct tm tm; + gsize retval; + + g_return_val_if_fail (d != NULL, 0); + g_return_val_if_fail (g_date_valid (d), 0); + g_return_val_if_fail (slen > 0, 0); + g_return_val_if_fail (format != 0, 0); + g_return_val_if_fail (s != 0, 0); + + g_date_to_struct_tm (d, &tm); + + retval = strftime (s, slen, format, &tm); + if (retval == 0) + { + /* If retval == 0, the contents of s are undefined. We define + * them. + */ + s[0] = '\0'; + } + return retval; +} |