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Annotation of embedaddon/php/ext/calendar/sdncal.h, revision 1.1.1.1

1.1       misho       1: #ifndef SDNCAL_H
                      2: #define SDNCAL_H
                      3: /*
                      4:  * This code has been modified for use with PHP
                      5:  * by Shane Caraveo shane@caraveo.com
                      6:  * see below for more details
                      7:  *
                      8:  */
                      9: 
                     10: /* $selId: sdncal.h,v 2.0 1995/10/24 01:13:06 lees Exp $
                     11:  * Copyright 1993-1995, Scott E. Lee, all rights reserved.
                     12:  * Permission granted to use, copy, modify, distribute and sell so long as
                     13:  * the above copyright and this permission statement are retained in all
                     14:  * copies.  THERE IS NO WARRANTY - USE AT YOUR OWN RISK.
                     15:  */
                     16: 
                     17: /**************************************************************************
                     18:  *
                     19:  * This package defines a set of routines that convert calendar dates to
                     20:  * and from a serial day number (SDN).  The SDN is a serial numbering of
                     21:  * days where SDN 1 is November 25, 4714 BC in the Gregorian calendar and
                     22:  * SDN 2447893 is January 1, 1990.  This system of day numbering is
                     23:  * sometimes referred to as Julian days, but to avoid confusion with the
                     24:  * Julian calendar, it is referred to as serial day numbers here.  The term
                     25:  * Julian days is also used to mean the number of days since the beginning
                     26:  * of the current year.
                     27:  *
                     28:  * The SDN can be used as an intermediate step in converting from one
                     29:  * calendar system to another (such as Gregorian to Jewish).  It can also
                     30:  * be used for date computations such as easily comparing two dates,
                     31:  * determining the day of the week, finding the date of yesterday or
                     32:  * calculating the number of days between two dates.
                     33:  *
                     34:  * When using this software on 16 bit systems, be careful to store SDNs in
                     35:  * a long int, because it will not fit in the 16 bits that some systems
                     36:  * allocate to an int.
                     37:  *
                     38:  * For each calendar, there are two routines provided.  One converts dates
                     39:  * in that calendar to SDN and the other converts SDN to calendar dates.
                     40:  * The routines are named SdnTo<CALENDAR>() and <CALENDAR>ToSdn(), where
                     41:  * <CALENDAR> is the name of the calendar system.
                     42:  *
                     43:  * SDN values less than one are not supported.  If a conversion routine
                     44:  * returns an SDN of zero, this means that the date given is either invalid
                     45:  * or is outside the supported range for that calendar.
                     46:  *
                     47:  * At least some validity checks are performed on input dates.  For
                     48:  * example, a negative month number will result in the return of zero for
                     49:  * the SDN.  A returned SDN greater than one does not necessarily mean that
                     50:  * the input date was valid.  To determine if the date is valid, convert it
                     51:  * to SDN, and if the SDN is greater than zero, convert it back to a date
                     52:  * and compare to the original.  For example:
                     53:  *
                     54:  *    int y1, m1, d1;
                     55:  *    int y2, m2, d2;
                     56:  *    long int sdn;
                     57:  *    ...
                     58:  *    sdn = GregorianToSdn(y1, m1, d1);
                     59:  *    if (sdn > 0) {
                     60:  *        SdnToGregorian(sdn, &y2, &m2, &d2);
                     61:  *        if (y1 == y2 && m1 == m2 && d1 == d2) {
                     62:  *            ... date is valid ...
                     63:  *        }
                     64:  *    }
                     65:  *
                     66:  **************************************************************************/
                     67: 
                     68: /* Gregorian calendar conversions. */
                     69: void SdnToGregorian(long int sdn, int *pYear, int *pMonth, int *pDay);
                     70: long int GregorianToSdn(int year, int month, int day);
                     71: extern char *MonthNameShort[13];
                     72: extern char *MonthNameLong[13];
                     73: 
                     74: /* Julian calendar conversions. */
                     75: void SdnToJulian(long int sdn, int *pYear, int *pMonth, int *pDay);
                     76: long int JulianToSdn(int year, int month, int day);
                     77: 
                     78: /* Jewish calendar conversions. */
                     79: void SdnToJewish(long int sdn, int *pYear, int *pMonth, int *pDay);
                     80: long int JewishToSdn(int year, int month, int day);
                     81: extern char *JewishMonthName[14];
                     82: extern char *JewishMonthHebName[14];
                     83: 
                     84: /* French republic calendar conversions. */
                     85: void SdnToFrench(long int sdn, int *pYear, int *pMonth, int *pDay);
                     86: long int FrenchToSdn(int inputYear, int inputMonth, int inputDay);
                     87: extern char *FrenchMonthName[14];
                     88: 
                     89: /* Islamic calendar conversions. */
                     90: /* Not implemented yet. */
                     91: 
                     92: /* Day of week conversion.  0=Sunday, 6=Saturday */
                     93: int DayOfWeek(long int sdn);
                     94: extern char *DayNameShort[7];
                     95: extern char *DayNameLong[7];
                     96: 
                     97: #endif /* SDNCAL_H */