glib/gdate.h

   1 /* GLIB - Library of useful routines for C programming
   2  * Copyright (C) 1995-1997  Peter Mattis, Spencer Kimball and Josh MacDonald
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser 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  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the
  16  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17  * Boston, MA 02111-1307, USA.
  18  */
  19
  20 /*
  21  * Modified by the GLib Team and others 1997-2000.  See the AUTHORS
  22  * file for a list of people on the GLib Team.  See the ChangeLog
  23  * files for a list of changes.  These files are distributed with
  24  * GLib at ftp://ftp.gtk.org/pub/gtk/.
  25  */
  26
  27 #if !defined (__GLIB_H_INSIDE__) && !defined (GLIB_COMPILATION)
  28 #error "Only <glib.h> can be included directly."
  29 #endif
  30
  31 #ifndef __G_DATE_H__
  32 #define __G_DATE_H__
  33
  34 #include <time.h>
  35
  36 #include <glib/gtypes.h>
  37 #include <glib/gquark.h>
  38
  39 G_BEGIN_DECLS
  40
  41 /* GDate
  42  *
  43  * Date calculations (not time for now, to be resolved). These are a
  44  * mutant combination of Steffen Beyer's DateCalc routines
  45  * (http://www.perl.com/CPAN/authors/id/STBEY/) and Jon Trowbridge's
  46  * date routines (written for in-house software).  Written by Havoc
  47  * Pennington <hp@pobox.com>
  48  */
  49
  50 typedef gint32  GTime;
  51 typedef guint16 GDateYear;
  52 typedef guint8  GDateDay;   /* day of the month */
  53 typedef struct _GDate GDate;
  54
  55 /* enum used to specify order of appearance in parsed date strings */
  56 typedef enum
  57 {
  58   G_DATE_DAY   = 0,
  59   G_DATE_MONTH = 1,
  60   G_DATE_YEAR  = 2
  61 } GDateDMY;
  62
  63 /* actual week and month values */
  64 typedef enum
  65 {
  66   G_DATE_BAD_WEEKDAY  = 0,
  67   G_DATE_MONDAY       = 1,
  68   G_DATE_TUESDAY      = 2,
  69   G_DATE_WEDNESDAY    = 3,
  70   G_DATE_THURSDAY     = 4,
  71   G_DATE_FRIDAY       = 5,
  72   G_DATE_SATURDAY     = 6,
  73   G_DATE_SUNDAY       = 7
  74 } GDateWeekday;
  75 typedef enum
  76 {
  77   G_DATE_BAD_MONTH = 0,
  78   G_DATE_JANUARY   = 1,
  79   G_DATE_FEBRUARY  = 2,
  80   G_DATE_MARCH     = 3,
  81   G_DATE_APRIL     = 4,
  82   G_DATE_MAY       = 5,
  83   G_DATE_JUNE      = 6,
  84   G_DATE_JULY      = 7,
  85   G_DATE_AUGUST    = 8,
  86   G_DATE_SEPTEMBER = 9,
  87   G_DATE_OCTOBER   = 10,
  88   G_DATE_NOVEMBER  = 11,
  89   G_DATE_DECEMBER  = 12
  90 } GDateMonth;
  91
  92 #define G_DATE_BAD_JULIAN 0U
  93 #define G_DATE_BAD_DAY    0U
  94 #define G_DATE_BAD_YEAR   0U
  95
  96 /* Note: directly manipulating structs is generally a bad idea, but
  97  * in this case it's an *incredibly* bad idea, because all or part
  98  * of this struct can be invalid at any given time. Use the functions,
  99  * or you will get hosed, I promise.
 100  */
 101 struct _GDate
 102 {
 103   guint julian_days : 32; /* julian days representation - we use a
 104                            *  bitfield hoping that 64 bit platforms
 105                            *  will pack this whole struct in one big
 106                            *  int
 107                            */
 108
 109   guint julian : 1;    /* julian is valid */
 110   guint dmy    : 1;    /* dmy is valid */
 111
 112   /* DMY representation */
 113   guint day    : 6;
 114   guint month  : 4;
 115   guint year   : 16;
 116 };
 117
 118 /* g_date_new() returns an invalid date, you then have to _set() stuff
 119  * to get a usable object. You can also allocate a GDate statically,
 120  * then call g_date_clear() to initialize.
 121  */
 122 GDate*       g_date_new                   (void);
 123 GDate*       g_date_new_dmy               (GDateDay     day,
 124                                            GDateMonth   month,
 125                                            GDateYear    year);
 126 GDate*       g_date_new_julian            (guint32      julian_day);
 127 void         g_date_free                  (GDate       *date);
 128
 129 /* check g_date_valid() after doing an operation that might fail, like
 130  * _parse.  Almost all g_date operations are undefined on invalid
 131  * dates (the exceptions are the mutators, since you need those to
 132  * return to validity).
 133  */
 134 gboolean     g_date_valid                 (const GDate *date);
 135 gboolean     g_date_valid_day             (GDateDay     day) G_GNUC_CONST;
 136 gboolean     g_date_valid_month           (GDateMonth month) G_GNUC_CONST;
 137 gboolean     g_date_valid_year            (GDateYear  year) G_GNUC_CONST;
 138 gboolean     g_date_valid_weekday         (GDateWeekday weekday) G_GNUC_CONST;
 139 gboolean     g_date_valid_julian          (guint32 julian_date) G_GNUC_CONST;
 140 gboolean     g_date_valid_dmy             (GDateDay     day,
 141                                            GDateMonth   month,
 142                                            GDateYear    year) G_GNUC_CONST;
 143
 144 GDateWeekday g_date_get_weekday           (const GDate *date);
 145 GDateMonth   g_date_get_month             (const GDate *date);
 146 GDateYear    g_date_get_year              (const GDate *date);
 147 GDateDay     g_date_get_day               (const GDate *date);
 148 guint32      g_date_get_julian            (const GDate *date);
 149 guint        g_date_get_day_of_year       (const GDate *date);
 150 /* First monday/sunday is the start of week 1; if we haven't reached
 151  * that day, return 0. These are not ISO weeks of the year; that
 152  * routine needs to be added.
 153  * these functions return the number of weeks, starting on the
 154  * corrsponding day
 155  */
 156 guint        g_date_get_monday_week_of_year (const GDate *date);
 157 guint        g_date_get_sunday_week_of_year (const GDate *date);
 158 guint        g_date_get_iso8601_week_of_year (const GDate *date);
 159
 160 /* If you create a static date struct you need to clear it to get it
 161  * in a sane state before use. You can clear a whole array at
 162  * once with the ndates argument.
 163  */
 164 void         g_date_clear                 (GDate       *date,
 165                                            guint        n_dates);
 166
 167 /* The parse routine is meant for dates typed in by a user, so it
 168  * permits many formats but tries to catch common typos. If your data
 169  * needs to be strictly validated, it is not an appropriate function.
 170  */
 171 void         g_date_set_parse             (GDate       *date,
 172                                            const gchar *str);
 173 void         g_date_set_time_t            (GDate       *date,
 174                                            time_t       timet);
 175 void         g_date_set_time_val          (GDate       *date,
 176                                            GTimeVal    *timeval);
 177 #ifndef G_DISABLE_DEPRECATED
 178 GLIB_DEPRECATED_FOR(g_date_set_time_t)
 179 void         g_date_set_time              (GDate       *date,
 180                                            GTime        time_);
 181 #endif
 182 void         g_date_set_month             (GDate       *date,
 183                                            GDateMonth   month);
 184 void         g_date_set_day               (GDate       *date,
 185                                            GDateDay     day);
 186 void         g_date_set_year              (GDate       *date,
 187                                            GDateYear    year);
 188 void         g_date_set_dmy               (GDate       *date,
 189                                            GDateDay     day,
 190                                            GDateMonth   month,
 191                                            GDateYear    y);
 192 void         g_date_set_julian            (GDate       *date,
 193                                            guint32      julian_date);
 194 gboolean     g_date_is_first_of_month     (const GDate *date);
 195 gboolean     g_date_is_last_of_month      (const GDate *date);
 196
 197 /* To go forward by some number of weeks just go forward weeks*7 days */
 198 void         g_date_add_days              (GDate       *date,
 199                                            guint        n_days);
 200 void         g_date_subtract_days         (GDate       *date,
 201                                            guint        n_days);
 202
 203 /* If you add/sub months while day > 28, the day might change */
 204 void         g_date_add_months            (GDate       *date,
 205                                            guint        n_months);
 206 void         g_date_subtract_months       (GDate       *date,
 207                                            guint        n_months);
 208
 209 /* If it's feb 29, changing years can move you to the 28th */
 210 void         g_date_add_years             (GDate       *date,
 211                                            guint        n_years);
 212 void         g_date_subtract_years        (GDate       *date,
 213                                            guint        n_years);
 214 gboolean     g_date_is_leap_year          (GDateYear    year) G_GNUC_CONST;
 215 guint8       g_date_get_days_in_month     (GDateMonth   month,
 216                                            GDateYear    year) G_GNUC_CONST;
 217 guint8       g_date_get_monday_weeks_in_year  (GDateYear    year) G_GNUC_CONST;
 218 guint8       g_date_get_sunday_weeks_in_year  (GDateYear    year) G_GNUC_CONST;
 219
 220 /* Returns the number of days between the two dates.  If date2 comes
 221    before date1, a negative value is return. */
 222 gint         g_date_days_between          (const GDate *date1,
 223                                            const GDate *date2);
 224
 225 /* qsort-friendly (with a cast...) */
 226 gint         g_date_compare               (const GDate *lhs,
 227                                            const GDate *rhs);
 228 void         g_date_to_struct_tm          (const GDate *date,
 229                                            struct tm   *tm);
 230
 231 void         g_date_clamp                 (GDate *date,
 232                                            const GDate *min_date,
 233                                            const GDate *max_date);
 234
 235 /* Swap date1 and date2's values if date1 > date2. */
 236 void         g_date_order                 (GDate *date1, GDate *date2);
 237
 238 /* Just like strftime() except you can only use date-related formats.
 239  *   Using a time format is undefined.
 240  */
 241 gsize        g_date_strftime              (gchar       *s,
 242                                            gsize        slen,
 243                                            const gchar *format,
 244                                            const GDate *date);
 245
 246 #ifndef G_DISABLE_DEPRECATED
 247
 248 #define g_date_weekday                  g_date_get_weekday
 249 #define g_date_month                    g_date_get_month
 250 #define g_date_year                     g_date_get_year
 251 #define g_date_day                      g_date_get_day
 252 #define g_date_julian                   g_date_get_julian
 253 #define g_date_day_of_year              g_date_get_day_of_year
 254 #define g_date_monday_week_of_year      g_date_get_monday_week_of_year
 255 #define g_date_sunday_week_of_year      g_date_get_sunday_week_of_year
 256 #define g_date_days_in_month            g_date_get_days_in_month
 257 #define g_date_monday_weeks_in_year     g_date_get_monday_weeks_in_year
 258 #define g_date_sunday_weeks_in_year     g_date_get_sunday_weeks_in_year
 259
 260 #endif /* G_DISABLE_DEPRECATED */
 261
 262 G_END_DECLS
 263
 264 #endif /* __G_DATE_H__ */