plugins/fn-christian-date/functions.c

   1 /* vim: set sw=8: -*- Mode: C; tab-width: 8; indent-tabs-mode: t; c-basic-offset: 8 -*- */
   2 /*
   3  * fn-christian-date.c: Christian date functions.
   4  *
   5  * Author:
   6  *   Andreas J. Guelzow <aguelzow@pyrshep.ca>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  *
  13  * This program is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16  * GNU General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU General Public License
  19  * along with this program; if not, see <https://www.gnu.org/licenses/>.
  20  */
  21 #include <gnumeric-config.h>
  22 #include <gnumeric.h>
  23 #include <gnm-i18n.h>
  24 #include <func.h>
  25 #include <value.h>
  26
  27 #include <parse-util.h>
  28 #include <cell.h>
  29 #include <value.h>
  30 #include <mathfunc.h>
  31 #include <workbook.h>
  32 #include <sheet.h>
  33
  34 #include <math.h>
  35 #include <gnm-datetime.h>
  36
  37 #include <glib.h>
  38 #include <goffice/goffice.h>
  39 #include <gnm-plugin.h>
  40
  41 GNM_PLUGIN_MODULE_HEADER;
  42
  43 #define DATE_CONV(ep)           workbook_date_conv ((ep)->sheet->workbook)
  44
  45 static void
  46 eastersunday_calc_for_year (int year, GDate *date)
  47 {
  48         int month;
  49         int day;
  50         int century, n, k, i, j, l;
  51
  52         century = year/100;
  53         n = year - 19 * (year / 19);
  54         k = (century - 17) / 25;
  55         i = century - century / 4 - (century - k) / 3 + 19 * n + 15;
  56         i %= 30;
  57         i = i - (i / 28) * (1 - (i / 28) * (29 / (i+1)) * ((21 - n) / 11 ));
  58         j = year + year / 4 + i + 2 - century + century / 4;
  59         j %= 7;
  60         l = i - j;
  61         month = 3 + (l + 40) / 44;
  62         day = l + 28 - 31 * (month / 4);
  63
  64         g_date_clear (date, 1);
  65         g_date_set_dmy (date, day, month, year);
  66 }
  67
  68 static void
  69 eastersunday_calc_no_year (GDate *date, GODateConventions const *conv, int diff)
  70 {
  71         int year, serial;
  72         int today = go_date_timet_to_serial (time (NULL), conv);
  73
  74         go_date_serial_to_g (date, today, conv);
  75         year = g_date_get_year (date);
  76         eastersunday_calc_for_year (year, date);
  77         serial = go_date_g_to_serial (date, conv) + diff;
  78         if (serial < today)
  79                 eastersunday_calc_for_year (year + 1, date);
  80 }
  81
  82 static int
  83 adjust_year (int year, GODateConventions const *conv)
  84 {
  85         if (year < 0)
  86                 return -1;
  87         else if (year <= 29)
  88                 return 2000 + year;
  89         else if (year <= 99)
  90                 return 1900 + year;
  91         else if (year < (gnm_datetime_allow_negative () ? 1582
  92                          : go_date_convention_base (conv)))
  93                 return -1;
  94         else if (year > 9956)
  95                 return -1;
  96         else
  97                 return year;
  98 }
  99
 100 static GnmValue *
 101 eastersunday_calc (GnmValue const *val, GnmFuncEvalInfo *ei, int diff)
 102 {
 103         GODateConventions const *conv = DATE_CONV (ei->pos);
 104         GDate date;
 105         int serial;
 106
 107         if (val) {
 108                 int year = adjust_year (value_get_as_int (val), conv);
 109
 110                 if (year < 0)
 111                         return value_new_error_NUM (ei->pos);
 112
 113                 eastersunday_calc_for_year (year, &date);
 114         } else
 115                 eastersunday_calc_no_year (&date, conv, diff);
 116
 117         serial = go_date_g_to_serial (&date, conv) + diff;
 118
 119         if (diff < 0 &&
 120             serial > 0 && serial <= 60 &&
 121             go_date_convention_base (conv) == 1900) {
 122                 /* We crossed the 29-Feb-1900 hole in the 1900 method.  */
 123                 serial--;
 124         }
 125
 126         return value_new_int (serial);
 127 }
 128
 129 /***************************************************************************/
 130
 131 static GnmFuncHelp const help_eastersunday[] = {
 132         { GNM_FUNC_HELP_NAME, F_("EASTERSUNDAY:Easter Sunday in the Gregorian calendar "
 133                                  "according to the Roman rite of the Christian Church") },
 134         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Easter Sunday")},
 135         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 136         { GNM_FUNC_HELP_EXAMPLES, "=EASTERSUNDAY(2001)" },
 137         { GNM_FUNC_HELP_EXAMPLES, "=EASTERSUNDAY()" },
 138         { GNM_FUNC_HELP_ODF, F_("The 1-argument version of EASTERSUNDAY is compatible with OpenOffice "
 139                                 "for years after 1904. "
 140                                 "This function is not specified in ODF/OpenFormula.")},
 141         { GNM_FUNC_HELP_SEEALSO, "ASHWEDNESDAY"},
 142         { GNM_FUNC_HELP_END }
 143 };
 144
 145 static GnmValue *
 146 gnumeric_eastersunday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 147 {
 148         return eastersunday_calc (argv[0], ei, 0);
 149 }
 150
 151
 152 /***************************************************************************/
 153
 154 static GnmFuncHelp const help_ashwednesday[] = {
 155         { GNM_FUNC_HELP_NAME, F_("ASHWEDNESDAY:Ash Wednesday in the Gregorian calendar "
 156                                  "according to the Roman rite of the Christian Church") },
 157         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Ash Wednesday")},
 158         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 159         { GNM_FUNC_HELP_EXAMPLES, "=ASHWEDNESDAY(2001)" },
 160         { GNM_FUNC_HELP_EXAMPLES, "=ASHWEDNESDAY()" },
 161         { GNM_FUNC_HELP_SEEALSO, "EASTERSUNDAY"},
 162         { GNM_FUNC_HELP_END }
 163 };
 164
 165 static GnmValue *
 166 gnumeric_ashwednesday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 167 {
 168         return eastersunday_calc (argv[0], ei, -46);
 169 }
 170
 171
 172 /***************************************************************************/
 173
 174 static GnmFuncHelp const help_pentecostsunday[] = {
 175         { GNM_FUNC_HELP_NAME, F_("PENTECOSTSUNDAY:Pentecost Sunday in the Gregorian calendar "
 176                                  "according to the Roman rite of the Christian Church") },
 177         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Pentecost Sunday")},
 178         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 179         { GNM_FUNC_HELP_EXAMPLES, "=PENTECOSTSUNDAY(2001)" },
 180         { GNM_FUNC_HELP_EXAMPLES, "=PENTECOSTSUNDAY()" },
 181         { GNM_FUNC_HELP_SEEALSO, "EASTERSUNDAY"},
 182         { GNM_FUNC_HELP_END }
 183 };
 184
 185 static GnmValue *
 186 gnumeric_pentecostsunday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 187 {
 188         return eastersunday_calc (argv[0], ei, +49);
 189 }
 190
 191 /***************************************************************************/
 192
 193 static GnmFuncHelp const help_goodfriday[] = {
 194         { GNM_FUNC_HELP_NAME, F_("GOODFRIDAY:Good Friday in the Gregorian calendar "
 195                                  "according to the Roman rite of the Christian Church") },
 196         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Good Friday")},
 197         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 198         { GNM_FUNC_HELP_EXAMPLES, "=GOODFRIDAY(2001)" },
 199         { GNM_FUNC_HELP_EXAMPLES, "=GOODFRIDAY()" },
 200         { GNM_FUNC_HELP_SEEALSO, "EASTERSUNDAY"},
 201         { GNM_FUNC_HELP_END }
 202 };
 203
 204 static GnmValue *
 205 gnumeric_goodfriday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 206 {
 207         return eastersunday_calc (argv[0], ei, -2);
 208 }
 209
 210 /***************************************************************************/
 211
 212 static GnmFuncHelp const help_ascensionthursday[] = {
 213         { GNM_FUNC_HELP_NAME, F_("ASCENSIONTHURSDAY:Ascension Thursday in the Gregorian calendar "
 214                                  "according to the Roman rite of the Christian Church") },
 215         { GNM_FUNC_HELP_ARG, F_("year:year between 1582 and 9956, defaults to the year of the next Ascension Thursday")},
 216         { GNM_FUNC_HELP_NOTE, F_("Two digit years are adjusted as elsewhere in Gnumeric. Dates before 1904 may also be prohibited.")},
 217         { GNM_FUNC_HELP_EXAMPLES, "=ASCENSIONTHURSDAY(2001)" },
 218         { GNM_FUNC_HELP_EXAMPLES, "=ASCENSIONTHURSDAY()" },
 219         { GNM_FUNC_HELP_SEEALSO, "EASTERSUNDAY"},
 220         { GNM_FUNC_HELP_END }
 221 };
 222
 223 static GnmValue *
 224 gnumeric_ascensionthursday (GnmFuncEvalInfo * ei, GnmValue const * const *argv)
 225 {
 226         return eastersunday_calc (argv[0], ei, +39);
 227 }
 228
 229 /***************************************************************************/
 230
 231 GnmFuncDescriptor const christian_datetime_functions[] = {
 232         {"ascensionthursday", "|f", help_ascensionthursday,
 233          gnumeric_ascensionthursday, NULL, NULL, NULL,
 234          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 235          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 236          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 237         {"ashwednesday", "|f", help_ashwednesday,
 238          gnumeric_ashwednesday, NULL, NULL, NULL,
 239          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 240          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 241          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 242         {"eastersunday", "|f", help_eastersunday,
 243          gnumeric_eastersunday, NULL, NULL, NULL,
 244          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 245          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 246          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 247         {"goodfriday", "|f", help_goodfriday,
 248          gnumeric_goodfriday, NULL, NULL, NULL,
 249          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 250          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 251          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 252         {"pentecostsunday", "|f", help_pentecostsunday,
 253          gnumeric_pentecostsunday, NULL, NULL, NULL,
 254          GNM_FUNC_VOLATILE + GNM_FUNC_AUTO_DATE,
 255          GNM_FUNC_IMPL_STATUS_UNIQUE_TO_GNUMERIC,
 256          GNM_FUNC_TEST_STATUS_NO_TESTSUITE},
 257         {NULL}
 258 };