Public header file for hconverter library.

Data Structures
struct	hc_date_s

struct	heb_time_s
	Hebrew time: hour and parts. More...

Typedefs
typedef enum hc_day_of_week	hc_day_of_week

typedef enum hc_calendar_type	hc_calendar_type
	Supported types of calendar. More...

typedef struct hc_date_s	hc_date

typedef struct heb_time_s	heb_time
	Hebrew time: hour and parts. More...

typedef enum heb_year_type	heb_year_type
	enum of possible layouts of the variable length Hebrew months Cheshvan and Kislev in a given year. More...

Enumerations
enum	hc_day_of_week { SUNDAY, MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY, SATURDAY }

enum	hc_calendar_type { NONE, GREGORIAN, JULIAN, HEBREW }
	Supported types of calendar. More...

enum	heb_year_type { SHORT_HEB_YEAR, NORMAL_HEB_YEAR, FULL_HEB_YEAR }
	enum of possible layouts of the variable length Hebrew months Cheshvan and Kislev in a given year. More...

Functions
int	set_hc_date (hc_date *, int year, int month, int day, hc_calendar_type)

int	hc_convert (hc_date *date, hc_calendar_type target_calendar)
	This function converts a date from one calendar to another. More...

int	hc_check (hc_date *date)
	Check validity of data in hc_date. More...

int	hc_is_leap_year (int year, hc_calendar_type calendar_type)
	Check if year is leap in given calendar. More...

hc_day_of_week	hc_get_day_of_week (hc_date *date)
	Function to get day of week out of a hc_date. More...

int	hc_get_month_length (int year, int month, hc_calendar_type calendar_type)
	Function to get the length of a month. More...

int	hc_compute_keviut (const int year, int rosh_hashana_dow, int pesach_dow, int ck, int leap)
	Compute year "keviut" and put the result into 4 integers. More...

int	hc_set_hc_heb_time (heb_time *time, int hour, int part)
	Convenience method to set heb_time struct value. More...

int	hc_compute_molad_rosh_hashana (int year, hc_calendar_type cal_type, hc_date date, heb_time time)
	Compute the date time of molad of Rosh Hashana for given year. More...

int	hc_compute_molad (const int year, int month, const hc_calendar_type cal_type, hc_date date, heb_time time)
	Compute the date and time of molad (new moon according to the Hebrew calendar) for given year and month. More...

heb_year_type	hc_get_heb_year_type (int year)
	Compute number of days in excess of 58 in Cheshvan and Kislev combined. More...

Detailed Description

Public header file for hconverter library.

Date: Dec 29, 1998

Author: Isaac Mushinsky

Contains all functional offerings of this library: convert dates between Hebrew, Gregorian and Julian calendars as well as compute certain specific times for the new moon, types of Jewish year.

Note about Hebrew month ordering.

Although each Hebrew year starts with the month of Tishrei, Tishrei is not the first in the order of months. There are a couple of reasons for this. Nisan is called the "first month" in the Torah for most purposes. Also, on a Hebrew leap year the 13th month (adar 2) is added before Nisan, not before Tishrei. This makes it more convenient to senumerate months not in chronological order but rather starting from Nisan to the end of year (Elul), and then returning to Tishrei through Adar. Thus the Hebrew months here are represented by integers as follows:

Tishrei 7
Cheshvan 8
Kislev 9
Teveth 10
Shvat 11
Adar 12 (also Adar I on leap years)
Adar II 13 (only on Hebrew leap years)
Nisan 1
Iyar 2
Sivan 3
Tamuz 4
Menachem Av 5
Elul 6

so despite a lower month index, Nisan follows after Adar. For example, the date 5776-01-01 follows 5776-13-29 in yyyy-mm-dd notation.

Note about keviut

Keviut determines layout of the Jewish year, including all holidays and readings of the Torah. It is customary to abbreviate it to 4 parameters:

1 day of week of Rosh Hashana, i.e. the "new year", Tishrei 1
2 day of week of first day of Pesach, i.e. Nisan 15
3 combined length of Cheshvan and Kislev (see #hc_heb_year_type)
4 whether or not the year is leap

Only 14 combinations of these are actually possible.

Typedef Documentation

typedef enum hc_calendar_type hc_calendar_type

Supported types of calendar.

GREGORIAN
JULIAN
HEBREW

typedef struct hc_date_s hc_date

Structure representing a date.

typedef enum hc_day_of_week hc_day_of_week

Convenience enum for days of week: SUNDAY=0, MONDAY=1, ..., FRIDAY=6

typedef struct heb_time_s heb_time

Hebrew time: hour and parts.

This type is specific to Hebrew calendar. Time is measured in hours and chalokim ("parts"), which are 1/1080 of an hour.

typedef enum heb_year_type heb_year_type

enum of possible layouts of the variable length Hebrew months Cheshvan and Kislev in a given year.

SHORT_HEB_YEAR means that both Cheshvan and Kislev are 29 days long
NORMAL_HEB_YEAR means 29 days in Cheshvan and 30 days in Kislev
FULL_HEB_YEAR means that both months are 30 days long

Enumeration Type Documentation

enum hc_calendar_type

Supported types of calendar.

GREGORIAN
JULIAN
HEBREW

enum hc_day_of_week

Convenience enum for days of week: SUNDAY=0, MONDAY=1, ..., FRIDAY=6

enum heb_year_type

enum of possible layouts of the variable length Hebrew months Cheshvan and Kislev in a given year.

SHORT_HEB_YEAR means that both Cheshvan and Kislev are 29 days long
NORMAL_HEB_YEAR means 29 days in Cheshvan and 30 days in Kislev
FULL_HEB_YEAR means that both months are 30 days long

Function Documentation

int hc_check ( hc_date * date )

Check validity of data in hc_date.

Returns 1 if the date is valid, 0 if the date is invalid in corresponding calendar. The following are invalid: nonpositive Hebrew year, month less than 1 or more than number of months in given year, day less than one or more than days in month.

Parameters

[in] date an hc_date

Returns: 0 if invalid, 1 otherwise.

int hc_compute_keviut	(	const int	year,
		int *	rosh_hashana_dow,
		int *	pesach_dow,
		int *	ck,
		int *	leap
	)

Compute year "keviut" and put the result into 4 integers.

Keviut determines layout of the Jewish year, including all holidays and readings of the Torah. See keviut for more information. Here, we output the "keviut" parameters by setting values of 4 integers whose pointers are supplied with parameters. For any of these output parameters, null pointers are allowed and will be ignored, so users can pass NULL rather than allocate integers for output that they do not need.

Parameters

[in]	year	Hebrew year
[out]	rosh_hashana_dow	Day of week for Eosh Hashana (1 Tishrei)
[out]	pesach_dow	Day of week for Pesach (0 = saturday)
[out]	ck	returns 0, 1, 2 (SHORT, REGULAR, FULL) for number of days in excess of 58 in Chesh=van and Kislev combined. (see #hc_heb_year_type)
[out]	it	will return 1 for leap years and 0 otherwise

int hc_compute_molad	(	const int	year,
		int	month,
		const hc_calendar_type	cal_type,
		hc_date *	date,
		heb_time *	time
	)

Compute the date and time of molad (new moon according to the Hebrew calendar) for given year and month.

Output parameters are hc_date and heb_time objects, passed in to be populated. No New memory is allocated.

Parameters

[in]	year
[in]	month
[in]	hc_calendar_type	GREGORIAN, JULIAN or HEBREW
[out]	date	pointer to hc_date struct to store result
[out]	time	pointer to heb_time to store time result

int hc_compute_molad_rosh_hashana	(	int	year,
		hc_calendar_type	cal_type,
		hc_date *	date,
		heb_time *	time
	)

Compute the date time of molad of Rosh Hashana for given year.

This is equivalent to <hc_compute_molad> with month set to 7 (Tishrei).

The output params hc_date and heb_time objects are passed in to be populated.

Parameters

[in]	year
[in]	hc_calendar_type	GREGORINA, JULIAN or HEBREW
[out]	date	pointer to hc_date struct to store result
[out]	time	pointer to heb_time to store time result

int hc_convert	(	hc_date *	date,
		hc_calendar_type	target_calendar
	)

This function converts a date from one calendar to another.

The given hc_date structure is modified during this call, so no new memory is allocated here.

Parameters

[out]	date	This object will be modified so that it has the target hc_calendar_type set along with corresponding date.
[in]	target_calendar	see hc_calendar_type

Returns: 0 on success, -1 if the input date is invalid.

hc_day_of_week hc_get_day_of_week ( hc_date * date )

Function to get day of week out of a hc_date.

Parameters

date

Returns: a #hc_day of week: 0 for Saturday, 1 for Sunday, ..., 6 for Friday

heb_year_type hc_get_heb_year_type ( int year )

Compute number of days in excess of 58 in Cheshvan and Kislev combined.

Parameters

[in] year Hebrew year >=1

Returns

can take 3 values:

SHORT_HEB_YEAR (0) - both Cheshvan and Kislev 29 days long
NORMAL_HEB_YEAR (1) - 29 days in Cheshvan, 30 days in Kislev
FULL _HEB_YEAR (2) - 30 days in both Cheshvan and Kislev

int hc_get_month_length	(	int	year,
		int	month,
		hc_calendar_type	calendar_type
	)

Function to get the length of a month.

Parameters

[in]	year
[in]	month.	For Hebrew, see (note) about the special month order.
[in]	calendar_type	see hc_calendar_type

Returns: length of month in days

int hc_is_leap_year	(	int	year,
		hc_calendar_type	calendar_type
	)

Check if year is leap in given calendar.

For Gregorian or Julian calendar this means that length of the year is 366 days. In Hebrew calendar it means that the year has 13 months instead of 12.

Parameters

[in]	year	Hebrew year >=1
[in]	calendar_type	see hc_calendar_type

Returns: 1 for leap year, 0 for non-leap year

int hc_set_hc_heb_time	(	heb_time *	time,
		int	hour,
		int	part
	)

Convenience method to set heb_time struct value.

Parameters

param[out]	time
param[in]	hour
param[in]	part

int set_hc_date	(	hc_date *	,
		int	year,
		int	month,
		int	day,
		hc_calendar_type
	)

Convenience method to set the entire hc_date in one call.

Parameters

[out]	date	pointer to hc_date structure
[in]	year
[in]	month
[in]	day
[in]	calendar_type

Public header file for hconverter library.

Data Structures

Typedefs

Enumerations

Functions

Detailed Description

Public header file for hconverter library.

Note about Hebrew month ordering.

Note about keviut

Typedef Documentation

Enumeration Type Documentation

Function Documentation