plugins/fn-christian-date/functions.c

   1 /*
   2  * fn-christian-date.c: Christian date functions.
   3  *
   4  * Author:
   5  *   Andreas J. Guelzow <aguelzow@pyrshep.ca>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License as published by
   9  * the Free Software Foundation; either version 2 of the License, or
  10  * (at your option) any later version.
  11  *
  12  * This program is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  * GNU General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU General Public License
  18  * along with this program; if not, see <https://www.gnu.org/licenses/>.
  19  */
  20 #include <gnumeric-config.h>
  21 #include <gnumeric.h>
  22 #include <gnm-i18n.h>
  23 #include <func.h>
  24 #include <value.h>
  25
  26 #include <parse-util.h>
  27 #include <cell.h>
  28 #include <value.h>
  29 #include <mathfunc.h>
  30 #include <workbook.h>
  31 #include <sheet.h>
  32
  33 #include <math.h>
  34 #include <gnm-datetime.h>
  35
  36 #include <glib.h>
  37 #include <goffice/goffice.h>
  38 #include <gnm-plugin.h>
  39
  40 GNM_PLUGIN_MODULE_HEADER;
  41
  42 #define DATE_CONV(ep)           sheet_date_conv ((ep)->sheet)
  43
  44 static void
  45 eastersunday_calc_for_year (int year, GDate *date)
  46 {
  47         int month;
  48         int day;
  49         int century, n, k, i, j, l;
  50
  51         century = year/100;
  52         n = year - 19 * (year / 19);
  53         k = (century - 17) / 25;
  54         i = century - century / 4 - (century - k) / 3 + 19 * n + 15;
  55         i %= 30;
  56         i = i - (i / 28) * (1 - (i / 28) * (29 / (i+1)) * ((21 - n) / 11 ));
  57         j = year + year / 4 + i + 2 - century + century / 4;
  58         j %= 7;
  59         l = i - j;
  60         month = 3 + (l + 40) / 44;
  61         day = l + 28 - 31 * (month / 4);
  62
  63         g_date_clear (date, 1);
  64         g_date_set_dmy (date, day, month, year);
  65 }
  66
  67 static void
  68 eastersunday_calc_no_year (GDate *date, GODateConventions const *conv, int diff)
  69 {
  70         int year, serial;
  71         int today = go_date_timet_to_serial (time (NULL), conv);
  72
  73         go_date_serial_to_g (date, today, conv);
  74         year = g_date_get_year (date);
  75         eastersunday_calc_for_year (year, date);
  76         serial = go_date_g_to_serial (date, conv) + diff;
  77         if (serial < today)
  78                 eastersunday_calc_for_year (year + 1, date);
  79 }
  80
  81 static int
  82 adjust_year (int year, GODateConventions const *conv)
  83 {
  84         if (year < 0)
  85                 return -1;
  86         else if (year <= 29)
  87                 return 2000 + year;
  88         else if (year <= 99)
  89                 return 1900 + year;
  90         else if (year < (gnm_datetime_allow_negative () ? 1582
  91                          : go_date_convention_base (conv)))
  92                 return -1;
  93         else if (year > 9956)
  94                 return -1;
  95         else
  96                 return year;
  97 }
  98
  99 static GnmValue *
 100 eastersunday_calc (GnmValue const *val, GnmFuncEvalInfo *ei, int diff)
 101 {
 102         GODateConventions const *conv = DATE_CONV (ei->pos);
 103         GDate date;
 104         int serial;
 105
 106         if (val) {
 107                 int year = adjust_year (value_get_as_int (val), conv);
 108
 109                 if (year < 0)
 110                         return value_new_error_NUM (ei->pos);
 111
 112                 eastersunday_calc_for_year (year, &date);
 113         } else
 114                 eastersunday_calc_no_year (&date, conv, diff);
 115
 116         serial = go_date_g_to_serial (&date, conv) + diff;
 117
 118         if (diff < 0 &&
 119             serial > 0 && serial <= 60 &&
 120             go_date_convention_base (conv) == 1900) {
 121                 /* We crossed the 29-Feb-1900 hole in the 1900 method.  */
 122                 serial--;
 123         }
 124
 125         return value_new_int (serial);
 126 }
 127
 128 /***************************************************************************/
 129
 130 static GnmFuncHelp const help_eastersunday[] = {
 131         { GNM_FUNC_HELP_NAME, F_("EASTERSUNDAY:Easter Sunday in the Gregorian calendar "
 132                                  "according to the Roman rite of the Christian Church") },
 133         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Easter Sunday")},
 134         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 135         { GNM_FUNC_HELP_EXAMPLES, "=EASTERSUNDAY(2001)" },
 136         { GNM_FUNC_HELP_EXAMPLES, "=EASTERSUNDAY()" },
 137         { GNM_FUNC_HELP_ODF, F_("The 1-argument version of EASTERSUNDAY is compatible with OpenOffice "
 138                                 "for years after 1904. "
 139                                 "This function is not specified in ODF/OpenFormula.")},
 140         { GNM_FUNC_HELP_SEEALSO, "ASHWEDNESDAY"},
 141         { GNM_FUNC_HELP_END }
 142 };
 143
 144 static GnmValue *
 145 gnumeric_eastersunday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 146 {
 147         return eastersunday_calc (argv[0], ei, 0);
 148 }
 149
 150
 151 /***************************************************************************/
 152
 153 static GnmFuncHelp const help_ashwednesday[] = {
 154         { GNM_FUNC_HELP_NAME, F_("ASHWEDNESDAY:Ash Wednesday in the Gregorian calendar "
 155                                  "according to the Roman rite of the Christian Church") },
 156         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Ash Wednesday")},
 157         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 158         { GNM_FUNC_HELP_EXAMPLES, "=ASHWEDNESDAY(2001)" },
 159         { GNM_FUNC_HELP_EXAMPLES, "=ASHWEDNESDAY()" },
 160         { GNM_FUNC_HELP_SEEALSO, "EASTERSUNDAY"},
 161         { GNM_FUNC_HELP_END }
 162 };
 163
 164 static GnmValue *
 165 gnumeric_ashwednesday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 166 {
 167         return eastersunday_calc (argv[0], ei, -46);
 168 }
 169
 170
 171 /***************************************************************************/
 172
 173 static GnmFuncHelp const help_pentecostsunday[] = {
 174         { GNM_FUNC_HELP_NAME, F_("PENTECOSTSUNDAY:Pentecost Sunday in the Gregorian calendar "
 175                                  "according to the Roman rite of the Christian Church") },
 176         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Pentecost Sunday")},
 177         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 178         { GNM_FUNC_HELP_EXAMPLES, "=PENTECOSTSUNDAY(2001)" },
 179         { GNM_FUNC_HELP_EXAMPLES, "=PENTECOSTSUNDAY()" },
 180         { GNM_FUNC_HELP_SEEALSO, "EASTERSUNDAY"},
 181         { GNM_FUNC_HELP_END }
 182 };
 183
 184 static GnmValue *
 185 gnumeric_pentecostsunday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 186 {
 187         return eastersunday_calc (argv[0], ei, +49);
 188 }
 189
 190 /***************************************************************************/
 191
 192 static GnmFuncHelp const help_goodfriday[] = {
 193         { GNM_FUNC_HELP_NAME, F_("GOODFRIDAY:Good Friday in the Gregorian calendar "
 194                                  "according to the Roman rite of the Christian Church") },
 195         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Good Friday")},
 196         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 197         { GNM_FUNC_HELP_EXAMPLES, "=GOODFRIDAY(2001)" },
 198         { GNM_FUNC_HELP_EXAMPLES, "=GOODFRIDAY()" },
 199         { GNM_FUNC_HELP_SEEALSO, "EASTERSUNDAY"},
 200         { GNM_FUNC_HELP_END }
 201 };
 202
 203 static GnmValue *
 204 gnumeric_goodfriday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 205 {
 206         return eastersunday_calc (argv[0], ei, -2);
 207 }
 208
 209 /***************************************************************************/
 210
 211 static GnmFuncHelp const help_ascensionthursday[] = {
 212         { GNM_FUNC_HELP_NAME, F_("ASCENSIONTHURSDAY:Ascension Thursday in the Gregorian calendar "
 213                                  "according to the Roman rite of the Christian Church") },
 214         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Ascension Thursday")},
 215         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 216         { GNM_FUNC_HELP_EXAMPLES, "=ASCENSIONTHURSDAY(2001)" },
 217         { GNM_FUNC_HELP_EXAMPLES, "=ASCENSIONTHURSDAY()" },
 218         { GNM_FUNC_HELP_SEEALSO, "EASTERSUNDAY"},
 219         { GNM_FUNC_HELP_END }
 220 };
 221
 222 static GnmValue *
 223 gnumeric_ascensionthursday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 224 {
 225         return eastersunday_calc (argv[0], ei, +39);
 226 }
 227
 228 /***************************************************************************/
 229
 230 GnmFuncDescriptor const christian_datetime_functions[] = {
 231         {"ascensionthursday", "|f", help_ascensionthursday,
 232          gnumeric_ascensionthursday, NULL, NULL, NULL,
 233          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 234          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 235          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 236         {"ashwednesday", "|f", help_ashwednesday,
 237          gnumeric_ashwednesday, NULL, NULL, NULL,
 238          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 239          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 240          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 241         {"eastersunday", "|f", help_eastersunday,
 242          gnumeric_eastersunday, NULL, NULL, NULL,
 243          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 244          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 245          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 246         {"goodfriday", "|f", help_goodfriday,
 247          gnumeric_goodfriday, NULL, NULL, NULL,
 248          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 249          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 250          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 251         {"pentecostsunday", "|f", help_pentecostsunday,
 252          gnumeric_pentecostsunday, NULL, NULL, NULL,
 253          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 254          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 255          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 256         {NULL}
 257 };