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Diffstat (limited to 'korganizer/plugins/hebrew/converter.cpp')
| -rw-r--r-- | korganizer/plugins/hebrew/converter.cpp | 345 |
1 files changed, 345 insertions, 0 deletions
diff --git a/korganizer/plugins/hebrew/converter.cpp b/korganizer/plugins/hebrew/converter.cpp new file mode 100644 index 000000000..1381292e6 --- /dev/null +++ b/korganizer/plugins/hebrew/converter.cpp @@ -0,0 +1,345 @@ +/*************************************************************************** + * Copyright (C) 2003 by Jonathan Singer * + * [email protected] * + * Calendar routines from Hebrew Calendar by Frank Yellin * + * * + * 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 of the License, or * + * (at your option) any later version. * + ***************************************************************************/ +#include "converter.h" +#include <klocale.h> + +Converter::Converter() +{ + +} + +Converter::~Converter() +{ +} + +long Converter::absolute_from_gregorian(int year, int month, int day) +{ + int xyear, day_number; + + xyear = year - 1; + day_number = day + 31 * (month - 1); + if (month > 2) + { + day_number -= (23 + (4 * month)) / 10; + if (gregorian_leap_year_p(year)) + day_number++; + } + return day_number + /* the day number within the current year */ + 365L * xyear + /* days in prior years */ + (xyear / 4) + /* Julian leap years */ + (-(xyear / 100)) + /* deduct century years */ + (xyear / 400); /* add Gregorian leap years */ +} + +/* Given a Hebrew date, calculate the number of days since + * January 0, 0001, Gregorian + */ +long Converter::absolute_from_hebrew(int year, int month, int day) +{ + long sum = day + hebrew_elapsed_days(year) - 1373429L; + int i; + + if (month < 7) + { + int months = hebrew_months_in_year(year); + + for (i = 7; i <= months; ++i) + sum += hebrew_month_length(year, i); + for (i = 1; i < month; ++i) + sum += hebrew_month_length(year, i); + } + else + { + for (i = 7; i < month; ++i) + sum += hebrew_month_length(year, i); + } + return sum; +} + +/* Given an absolute date, calculate the gregorian date */ +void + Converter::gregorian_from_absolute(long date, int *yearp, + int *monthp, int *dayp) +{ + int year, month, day; + + for (year = date / 366; + date >= absolute_from_gregorian(year + 1, 1, 1); ++year) ; + for (month = 1; + (month <= 11) + && (date >= absolute_from_gregorian(year, 1 + month, 1)); + ++month ) ; + day = 1 + date - absolute_from_gregorian(year, month, 1); + *yearp = year; + *monthp = month; + *dayp = day; +} + +/* Given an absolute date, calculate the Hebrew date */ +void + Converter::hebrew_from_absolute(long date, int *yearp, int *monthp, + int *dayp) +{ + int year, month, day, gyear, gmonth, gday, months; + + gregorian_from_absolute(date, &gyear, &gmonth, &gday); + year = gyear + 3760; + while (date >= absolute_from_hebrew(1 + year, 7, 1)) + year++; + months = hebrew_months_in_year(year); + for (month = 7; + date > absolute_from_hebrew(year, month, + hebrew_month_length(year, month)); + month = 1 + (month % months)) ; + day = 1 + date - absolute_from_hebrew(year, month, 1); + *yearp = year; + *monthp = month; + *dayp = day; +} + +/* Number of months in a Hebrew year */ +int Converter::hebrew_months_in_year(int year) +{ + if (hebrew_leap_year_p(year)) + return 13; + else + return 12; +} + +enum +{ Nissan = + 1, Iyar, Sivan, Tamuz, Ab, Elul, Tishrei, Cheshvan, Kislev, Tevet, + Shvat, Adar, AdarII, AdarI = 12 +}; + +enum +{ January = + 1, February, March, April, May, June, July, August, September, + October, November, December +}; + +/* Number of days in a Hebrew month */ +int Converter::hebrew_month_length(int year, int month) +{ + switch (month) + { + case Tishrei: + case Shvat: + case Nissan: + case Sivan: + case Ab: + return 30; + + case Tevet: + case Iyar: + case Tamuz: + case Elul: + case AdarII: + return 29; + + case Cheshvan: + // 29 days, unless it's a long year. + if ((hebrew_year_length(year) % 10) == 5) + return 30; + else + return 29; + + case Kislev: + // 30 days, unless it's a short year. + if ((hebrew_year_length(year) % 10) == 3) + return 29; + else + return 30; + + case Adar: + // Adar (non-leap year) has 29 days. Adar I has 30 days. + if (hebrew_leap_year_p(year)) + return 30; + else + return 29; + + default: + return 0; + } +} + +/* Number of days in a Julian or gregorian month */ +int + Converter::secular_month_length(int year, + int month /*, bool julianp */ ) +{ + switch (month) + { + case January: + case March: + case May: + case July: + case August: + case October: + case December: + return 31; + case April: + case June: + case September: + case November: + return 30; + case February: + if (gregorian_leap_year_p(year)) + return 29; + else + return 28; + default: + return 0; + } +} + +/* Is it a Leap year in the gregorian calendar */ +bool Converter::gregorian_leap_year_p(int year) +{ + if ((year % 4) != 0) + return 0; + if ((year % 400) == 0) + return 1; + if ((year % 100) == 0) + return 0; + return 1; +} + +/* Is it a leap year in the Jewish Calendar */ +bool Converter::hebrew_leap_year_p(int year) +{ + switch (year % 19) + { + case 0: + case 3: + case 6: + case 8: + case 11: + case 14: + case 17: + return 1; + default: + return 0; + } +} + +/* Return the number of days from 1 Tishrei 0001 to the beginning of the given year. + * Since this routine gets called frequently with the same year arguments, we cache + * the most recent values. + */ +#define MEMORY 5 +long Converter::hebrew_elapsed_days(int year) +{ + static int saved_year[MEMORY] = { -1, -1, -1, -1, -1 }; + static long saved_value[MEMORY]; + int i; + + for (i = 0; i < MEMORY; ++i) + if (year == saved_year[i]) + return saved_value[i]; + for (i = 0; i < MEMORY-1; ++i) { + saved_year[i] = saved_year[1 + i]; + saved_value[i] = saved_value[1 + i]; + } + saved_year[MEMORY - 1] = year; + saved_value[MEMORY - 1] = hebrew_elapsed_days2(year); + return saved_value[MEMORY - 1]; +} + +long Converter::hebrew_elapsed_days2(int year) +{ + long prev_year = year - 1; + long months_elapsed = 235L * (prev_year / 19) /* months in complete cycles so far */ + + 12L * (prev_year % 19) /* regular months in this cycle */ + + (((prev_year % 19) * 7 + 1) / 19); /* leap months this cycle */ + long parts_elapsed = 5604 + 13753 * months_elapsed; + long day = 1 + 29 * months_elapsed + parts_elapsed / 25920; + long parts = parts_elapsed % 25920; + int weekday = (day % 7); + long alt_day = ((parts >= 19440) + || (weekday == 2 && (parts >= 9924) + && !hebrew_leap_year_p(year)) || (weekday == 1 + && (parts >= + 16789) + && + hebrew_leap_year_p + (prev_year))) + ? day + 1 : day; + switch (alt_day % 7) + { + case 0: + case 3: + case 5: + return 1 + alt_day; + default: + return alt_day; + } +} + +/* Number of days in the given Hebrew year */ +int Converter::hebrew_year_length(int year) +{ + return hebrew_elapsed_days(1 + year) - hebrew_elapsed_days(year); +} + +/* Fill in the DateResult structure based on the given secular date */ +void + Converter::SecularToHebrewConversion(int syear, int smonth, + int sday, + struct DateResult *result) +{ + int hyear, hmonth, hday; + long absolute; + + absolute = absolute_from_gregorian(syear, smonth, sday); + + hebrew_from_absolute(absolute, &hyear, &hmonth, &hday); + + result->year = hyear; + result->month = hmonth; + result->day = hday; + finish_up(absolute, hyear, hmonth, syear, smonth, result); +} + +/* Fill in the DateResult structure based on the given Hebrew date */ +void + Converter::HebrewToSecularConversion(int hyear, int hmonth, + int hday, + struct DateResult *result) +{ + int syear, smonth, sday; + long absolute; + + absolute = absolute_from_hebrew(hyear, hmonth, hday); + gregorian_from_absolute(absolute, &syear, &smonth, &sday); + result->year = hyear; + result->month = hmonth; + result->day = hday; + finish_up(absolute, hyear, hmonth, syear, smonth, result); +} + +/* This is common code for filling up the DateResult structure */ +void + Converter::finish_up(long absolute, int hyear, int hmonth, + int syear, int smonth, + struct DateResult *result) +{ + result->hebrew_month_length = hebrew_month_length(hyear, hmonth); + result->secular_month_length = secular_month_length(syear, smonth); + result->hebrew_leap_year_p = hebrew_leap_year_p(hyear); + result->secular_leap_year_p = gregorian_leap_year_p(syear); + result->kvia = (hebrew_year_length(hyear) % 10) - 3; + // absolute is -1 on 1/1/0001 Julian + result->day_of_week = (7 + absolute) % 7; + result->hebrew_day_number = + absolute - absolute_from_hebrew(hyear, 7, 1) + 1; + +} |