/*************************************************************************** vbdate.c (c) 2000-2003 Nigel Gerrard This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. This program 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 General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. ***************************************************************************/ #define __VBDATE_C #include "vbdate.h" #include #include #define DATE_YEAR_MIN -4801 #define DATE_YEAR_MAX 9999 /* Helper functions */ const char 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 */ }; const short 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 } /* leap year */ }; /* Returns 1 for a leap year, 0 else */ int date_is_leap_year(short year) { if (year < 0) year += 8001; if ((((year % 4) == 0) && ((year % 100) != 0)) || (year % 400) == 0) return 1; else return 0; } int date_is_valid(GB_DATE_SERIAL *date) { return ((date->month >= 1) && (date->month <= 12) && (date->year >= DATE_YEAR_MIN) && (date->year <= DATE_YEAR_MAX) && (date->year != 0) && (date->day >= 1) && (date->day <= days_in_months[date_is_leap_year(date->year)][(short)date->month]) && (date->hour >= 0) && (date->hour <= 23) && (date->min >= 0) && (date->min <= 59) && (date->sec >= 0) && (date->sec <= 59)); } /** Modulo function that works correctly for negative divisors */ //#define modulo(x,y) ((x)%(y)<0?(x)%(y)+(y):(x)%(y)) static int modulo(int x, int y) { int mod = x % y; if (mod < 0) mod += y; return mod; } void DATE_adjust( GB_DATE *vdate, int period, int interval) /* Adjust the date by the interval period */ { GB_DATE_SERIAL *date; int year, month, day; date = GB.SplitDate(vdate); switch(period){ case 0: /* Calendar Month */ year = ((date->year * 12) + (date->month - 1) + interval)/12; month = modulo((date->month - 1)+interval, 12) + 1; day = date->day > days_in_months[date_is_leap_year(year)][month] ? days_in_months[date_is_leap_year(year)][month] : date->day; date->day = day; date->month = month; date->year = year; GB.MakeDate(date, vdate); break; case 1: /* days */ vdate->value.date += interval; break; case 2: /* Time */ vdate->value.time += interval; break; case 3: /* weekdays - in this case weekdays are Mon - Fri */ vdate->value.date += ( 7 * ( interval / 5)); date->weekday += ( interval % 5 ); if (date->weekday > 5){ date->weekday -= 5; vdate->value.date += 2; } if (date->weekday < 1){ date->weekday += 5; vdate->value.date -= 2; } vdate->value.date += ( interval % 5); break; case 4: /* Add year */ while ( interval != 0){ if ( interval < 0 ){ vdate->value.date -= days_in_year[date_is_leap_year(date->year)][13]; date->year--; interval++; } else { vdate->value.date += days_in_year[date_is_leap_year(date->year)][13]; date->year++; interval--; } } break; } /* Now if time takes it into another day */ while (vdate->value.time >= 86400000){ vdate->value.date++; vdate->value.time -= 86400000; } /* Or time is negative so we need to take off a day */ while (vdate->value.time < 0){ vdate->value.date--; vdate->value.time += 86400000; } CLEAR(&date); date = GB.SplitDate(vdate); if (!date_is_valid(date)){ /*printf("Invalid date : year [%i] month [%i] day [%i] hour [%i] min [%i] sec [%i] weekday [%i] msec [%i]\n", date->year, date->month, date->day, date->hour, date->min, date->sec, date->weekday, date->msec);*/ GB.Error("Invalid Date Returned"); } CLEAR(&date); } int DATE_diff( GB_DATE *vdate1, GB_DATE *vdate2, int period) { GB_DATE_SERIAL *date1, *date2; int diff = 0; int year1, year2, month1, month2, weekday1, weekday2; date1 = GB.SplitDate(vdate1); weekday1 = date1->weekday; year1 = date1->year; month1 = date1->month; date2 = GB.SplitDate(vdate2); weekday2 = date2->weekday; year2 = date2->year; month2 = date2->month; switch(period){ case 0: /* Calendar Month */ diff = ((year1 * 12) + month1) - ((year2 * 12) + month2); break; case 1: /* days */ diff = vdate1->value.date - vdate2->value.date; break; case 2: /* Time */ diff = ((vdate1->value.date - vdate2->value.date) * 86400000) + (vdate1->value.time - vdate2->value.time); break; case 3: /* weekdays */ /* If invalid weekday then find closest valid day: * eg. 7 -1, 6 -5*/ weekday1 == 7 ? weekday1 = 1 : weekday1 == 6 ? weekday1 = 5 : weekday1; weekday2 == 7 ? weekday2 = 1 : weekday2 == 6 ? weekday2 = 5 : weekday2; diff = (((vdate1->value.date - vdate2->value.date) / 7) * 5) + (weekday1 - weekday2); /* Needs validating */ break; case 4: /* year */ diff = year1 - year2; break; case 5: /* Weeks */ diff = (vdate1->value.date - vdate2->value.date)/7; break; } CLEAR(&date1); CLEAR(&date2); return diff; } /* End Helper functions */ /* GB_DESC CVbDateDesc[] = { GB_DECLARE("Vb", 0), GB_NOT_CREATABLE(), GB_STATIC_METHOD("DateAdd", "d", CVB_DateAdd, "(period)s(interval)i(Date)v"), GB_STATIC_METHOD("DateDiff", "i", CVB_DateDiff, "(period)s(Date1)v(Date2)v"), GB_END_DECLARE };*/