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Diffstat (limited to 'www/wiki/extensions/SemanticMediaWiki/src/DataValues/Time/JulianDay.php')
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diff --git a/www/wiki/extensions/SemanticMediaWiki/src/DataValues/Time/JulianDay.php b/www/wiki/extensions/SemanticMediaWiki/src/DataValues/Time/JulianDay.php new file mode 100644 index 00000000..150b206d --- /dev/null +++ b/www/wiki/extensions/SemanticMediaWiki/src/DataValues/Time/JulianDay.php @@ -0,0 +1,200 @@ +<?php + +namespace SMW\DataValues\Time; + +use RuntimeException; + +/** + * Julian dates (abbreviated JD) are a continuous count of days and fractions + * since noon Universal Time on January 1, 4713 BCE (on the Julian calendar). + * + * It is assumed that the changeover from the Julian calendar to the Gregorian + * calendar occurred in October of 1582. + * + * For dates on or before 4 October 1582, the Julian calendar is used; for dates + * on or after 15 October 1582, the Gregorian calendar is used. + * + * @license GNU GPL v2+ + * @since 2.4 + * + * @author Markus Krötzsch + */ +class JulianDay implements CalendarModel { + + /** + * Moment of switchover to Gregorian calendar. + */ + const J1582 = 2299160.5; + + /** + * Offset of Julian Days for Modified JD inputs. + */ + const MJD = 2400000.5; + + /** + * @since 2.4 + * + * @param integer $calendarmodel + * @param integer $year + * @param integer $month + * @param integer $day + * @param integer $hour + * @param integer $minute + * @param integer $second + * + * @return float + */ + public static function getJD( $calendarModel = self::CM_GREGORIAN, $year, $month, $day, $hour, $minute, $second ) { + return self::format( self::date2JD( $calendarModel, $year, $month, $day ) + self::time2JDoffset( $hour, $minute, $second ) ); + } + + /** + * Return a formatted value + * + * @note April 25, 2017 20:00-4:00 is expected to be 2457869.5 and not + * 2457869.4999999665 hence apply the same formatting on all values to avoid + * some unexpected behaviour as observed in #2454 + * + * @since 3.0 + * + * @param $value + * + * @return float + */ + public static function format( $value ) { + // Keep microseconds to a certain degree distinguishable + return floatval( number_format( $value, 7, '.', '' ) ); + } + + /** + * The MJD has a starting point of midnight on November 17, 1858 and is + * computed by MJD = JD - 2400000.5 + * + * @since 2.4 + * + * @param float jdValue + * + * @return float + */ + public static function getModifiedJulianDate( $jdValue ) { + return $jdValue - self::MJD; + } + + /** + * Compute the Julian Day number from a given date in the specified + * calendar model. This calculation assumes that neither calendar + * has a year 0. + * + * @param $year integer representing the year + * @param $month integer representing the month + * @param $day integer representing the day + * @param $calendarmodel integer either CM_GREGORIAN or CM_JULIAN + * + * @return float Julian Day number + * @throws RuntimeException + */ + protected static function date2JD( $calendarmodel, $year, $month, $day ) { + $astroyear = ( $year < 1 ) ? ( $year + 1 ) : $year; + + if ( $calendarmodel === self::CM_GREGORIAN ) { + $a = intval( ( 14 - $month ) / 12 ); + $y = $astroyear + 4800 - $a; + $m = $month + 12 * $a - 3; + return $day + floor( ( 153 * $m + 2 ) / 5 ) + 365 * $y + floor( $y / 4 ) - floor( $y / 100 ) + floor( $y / 400 ) - 32045.5; + } elseif ( $calendarmodel === self::CM_JULIAN ) { + $y2 = ( $month <= 2 ) ? ( $astroyear - 1 ) : $astroyear; + $m2 = ( $month <= 2 ) ? ( $month + 12 ) : $month; + return floor( ( 365.25 * ( $y2 + 4716 ) ) ) + floor( ( 30.6001 * ( $m2 + 1 ) ) ) + $day - 1524.5; + } + + throw new RuntimeException( "Unsupported calendar model ($calendarmodel)" ); + } + + /** + * Compute the offset for the Julian Day number from a given time. + * This computation is the same for all calendar models. + * + * @param $hours integer representing the hour + * @param $minutes integer representing the minutes + * @param $seconds integer representing the seconds + * + * @return float offset for a Julian Day number to get this time + */ + protected static function time2JDoffset( $hours, $minutes, $seconds ) { + return ( $hours / 24 ) + ( $minutes / ( 60 * 24 ) ) + ( $seconds / ( 3600 * 24 ) ); + } + + /** + * Convert a Julian Day number to a date in the given calendar model. + * This calculation assumes that neither calendar has a year 0. + * @note The algorithm may fail for some cases, in particular since the + * conversion to Gregorian needs positive JD. If this happens, wrong + * values will be returned. Avoid date conversions before 10000 BCE. + * + * @param $jdValue float number of Julian Days + * @param $calendarModel integer either CM_GREGORIAN or CM_JULIAN + * + * @return array( calendarModel, yearnumber, monthnumber, daynumber ) + * @throws RuntimeException + */ + public static function JD2Date( $jdValue, $calendarModel = null ) { + + if ( $calendarModel === null ) { // 1582/10/15 + $calendarModel = $jdValue < self::J1582 ? self::CM_JULIAN : self::CM_GREGORIAN; + } + + if ( $calendarModel === self::CM_GREGORIAN ) { + $jdValue += 2921940; // add the days of 8000 years (this algorithm only works for positive JD) + $j = floor( $jdValue + 0.5 ) + 32044; + $g = floor( $j / 146097 ); + $dg = $j % 146097; + $c = floor( ( ( floor( $dg / 36524 ) + 1 ) * 3 ) / 4 ); + $dc = $dg - $c * 36524; + $b = floor( $dc / 1461 ); + $db = $dc % 1461; + $a = floor( ( ( floor( $db / 365 ) + 1 ) * 3 ) / 4 ); + $da = $db - ( $a * 365 ); + $y = $g * 400 + $c * 100 + $b * 4 + $a; + $m = floor( ( $da * 5 + 308 ) / 153 ) - 2; + $d = $da - floor( ( ( $m + 4 ) * 153 ) / 5 ) + 122; + + $year = $y - 4800 + floor( ( $m + 2 ) / 12 ) - 8000; + $month = ( ( $m + 2 ) % 12 + 1 ); + $day = $d + 1; + } elseif ( $calendarModel === self::CM_JULIAN ) { + $b = floor( $jdValue + 0.5 ) + 1524; + $c = floor( ( $b - 122.1 ) / 365.25 ); + $d = floor( 365.25 * $c ); + $e = floor( ( $b - $d ) / 30.6001 ); + + $month = floor( ( $e < 14 ) ? ( $e - 1 ) : ( $e - 13 ) ); + $year = floor( ( $month > 2 ) ? ( $c - 4716 ) : ( $c - 4715 ) ); + $day = ( $b - $d - floor( 30.6001 * $e ) ); + } else { + throw new RuntimeException( "Unsupported calendar model ($calendarModel)" ); + } + + $year = ( $year < 1 ) ? ( $year - 1 ) : $year; // correct "year 0" to -1 (= 1 BC(E)) + + return [ $calendarModel, $year, $month, $day ]; + } + + /** + * Extract the time from a Julian Day number and return it as a string. + * This conversion is the same for all calendar models. + * + * @param $jdvalue float number of Julian Days + * @return array( hours, minutes, seconds ) + */ + public static function JD2Time( $jdvalue ) { + $wjd = $jdvalue + 0.5; + $fraction = $wjd - floor( $wjd ); + $time = round( $fraction * 3600 * 24 ); + $hours = floor( $time / 3600 ); + $time = $time - $hours * 3600; + $minutes = floor( $time / 60 ); + $seconds = floor( $time - $minutes * 60 ); + return [ $hours, $minutes, $seconds ]; + } + +} |