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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 19:33:14 +0000
commit36d22d82aa202bb199967e9512281e9a53db42c9 (patch)
tree105e8c98ddea1c1e4784a60a5a6410fa416be2de /intl/icu/source/i18n/gregoimp.h
parentInitial commit. (diff)
downloadfirefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.tar.xz
firefox-esr-36d22d82aa202bb199967e9512281e9a53db42c9.zip
Adding upstream version 115.7.0esr.upstream/115.7.0esrupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+ **********************************************************************
+ * Copyright (c) 2003-2008, International Business Machines
+ * Corporation and others. All Rights Reserved.
+ **********************************************************************
+ * Author: Alan Liu
+ * Created: September 2 2003
+ * Since: ICU 2.8
+ **********************************************************************
+ */
+
+#ifndef GREGOIMP_H
+#define GREGOIMP_H
+#include "unicode/utypes.h"
+#if !UCONFIG_NO_FORMATTING
+
+#include "unicode/ures.h"
+#include "unicode/locid.h"
+#include "putilimp.h"
+
+U_NAMESPACE_BEGIN
+
+/**
+ * A utility class providing mathematical functions used by time zone
+ * and calendar code. Do not instantiate. Formerly just named 'Math'.
+ * @internal
+ */
+class ClockMath {
+ public:
+ /**
+ * Divide two integers, returning the floor of the quotient.
+ * Unlike the built-in division, this is mathematically
+ * well-behaved. E.g., <code>-1/4</code> => 0 but
+ * <code>floorDivide(-1,4)</code> => -1.
+ * @param numerator the numerator
+ * @param denominator a divisor which must be != 0
+ * @return the floor of the quotient
+ */
+ static int32_t floorDivide(int32_t numerator, int32_t denominator);
+
+ /**
+ * Divide two integers, returning the floor of the quotient.
+ * Unlike the built-in division, this is mathematically
+ * well-behaved. E.g., <code>-1/4</code> => 0 but
+ * <code>floorDivide(-1,4)</code> => -1.
+ * @param numerator the numerator
+ * @param denominator a divisor which must be != 0
+ * @return the floor of the quotient
+ */
+ static int64_t floorDivide(int64_t numerator, int64_t denominator);
+
+ /**
+ * Divide two numbers, returning the floor of the quotient.
+ * Unlike the built-in division, this is mathematically
+ * well-behaved. E.g., <code>-1/4</code> => 0 but
+ * <code>floorDivide(-1,4)</code> => -1.
+ * @param numerator the numerator
+ * @param denominator a divisor which must be != 0
+ * @return the floor of the quotient
+ */
+ static inline double floorDivide(double numerator, double denominator);
+
+ /**
+ * Divide two numbers, returning the floor of the quotient and
+ * the modulus remainder. Unlike the built-in division, this is
+ * mathematically well-behaved. E.g., <code>-1/4</code> => 0 and
+ * <code>-1%4</code> => -1, but <code>floorDivide(-1,4)</code> =>
+ * -1 with <code>remainder</code> => 3. NOTE: If numerator is
+ * too large, the returned quotient may overflow.
+ * @param numerator the numerator
+ * @param denominator a divisor which must be != 0
+ * @param remainder output parameter to receive the
+ * remainder. Unlike <code>numerator % denominator</code>, this
+ * will always be non-negative, in the half-open range <code>[0,
+ * |denominator|)</code>.
+ * @return the floor of the quotient
+ */
+ static int32_t floorDivide(double numerator, int32_t denominator,
+ int32_t* remainder);
+
+ /**
+ * For a positive divisor, return the quotient and remainder
+ * such that dividend = quotient*divisor + remainder and
+ * 0 <= remainder < divisor.
+ *
+ * Works around edge-case bugs. Handles pathological input
+ * (dividend >> divisor) reasonably.
+ *
+ * Calling with a divisor <= 0 is disallowed.
+ */
+ static double floorDivide(double dividend, double divisor,
+ double* remainder);
+};
+
+// Useful millisecond constants
+#define kOneDay (1.0 * U_MILLIS_PER_DAY) // 86,400,000
+#define kOneHour (60*60*1000)
+#define kOneMinute 60000
+#define kOneSecond 1000
+#define kOneMillisecond 1
+#define kOneWeek (7.0 * kOneDay) // 604,800,000
+
+// Epoch constants
+#define kJan1_1JulianDay 1721426 // January 1, year 1 (Gregorian)
+
+#define kEpochStartAsJulianDay 2440588 // January 1, 1970 (Gregorian)
+
+#define kEpochYear 1970
+
+
+#define kEarliestViableMillis -185331720384000000.0 // minimum representable by julian day -1e17
+
+#define kLatestViableMillis 185753453990400000.0 // max representable by julian day +1e17
+
+/**
+ * The minimum supported Julian day. This value is equivalent to
+ * MIN_MILLIS.
+ */
+#define MIN_JULIAN (-0x7F000000)
+
+/**
+ * The minimum supported epoch milliseconds. This value is equivalent
+ * to MIN_JULIAN.
+ */
+#define MIN_MILLIS ((MIN_JULIAN - kEpochStartAsJulianDay) * kOneDay)
+
+/**
+ * The maximum supported Julian day. This value is equivalent to
+ * MAX_MILLIS.
+ */
+#define MAX_JULIAN (+0x7F000000)
+
+/**
+ * The maximum supported epoch milliseconds. This value is equivalent
+ * to MAX_JULIAN.
+ */
+#define MAX_MILLIS ((MAX_JULIAN - kEpochStartAsJulianDay) * kOneDay)
+
+/**
+ * A utility class providing proleptic Gregorian calendar functions
+ * used by time zone and calendar code. Do not instantiate.
+ *
+ * Note: Unlike GregorianCalendar, all computations performed by this
+ * class occur in the pure proleptic GregorianCalendar.
+ */
+class Grego {
+ public:
+ /**
+ * Return true if the given year is a leap year.
+ * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
+ * @return true if the year is a leap year
+ */
+ static inline UBool isLeapYear(int32_t year);
+
+ /**
+ * Return the number of days in the given month.
+ * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
+ * @param month 0-based month, with 0==Jan
+ * @return the number of days in the given month
+ */
+ static inline int8_t monthLength(int32_t year, int32_t month);
+
+ /**
+ * Return the length of a previous month of the Gregorian calendar.
+ * @param y the extended year
+ * @param m the 0-based month number
+ * @return the number of days in the month previous to the given month
+ */
+ static inline int8_t previousMonthLength(int y, int m);
+
+ /**
+ * Convert a year, month, and day-of-month, given in the proleptic
+ * Gregorian calendar, to 1970 epoch days.
+ * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
+ * @param month 0-based month, with 0==Jan
+ * @param dom 1-based day of month
+ * @return the day number, with day 0 == Jan 1 1970
+ */
+ static double fieldsToDay(int32_t year, int32_t month, int32_t dom);
+
+ /**
+ * Convert a 1970-epoch day number to proleptic Gregorian year,
+ * month, day-of-month, and day-of-week.
+ * @param day 1970-epoch day (integral value)
+ * @param year output parameter to receive year
+ * @param month output parameter to receive month (0-based, 0==Jan)
+ * @param dom output parameter to receive day-of-month (1-based)
+ * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
+ * @param doy output parameter to receive day-of-year (1-based)
+ */
+ static void dayToFields(double day, int32_t& year, int32_t& month,
+ int32_t& dom, int32_t& dow, int32_t& doy);
+
+ /**
+ * Convert a 1970-epoch day number to proleptic Gregorian year,
+ * month, day-of-month, and day-of-week.
+ * @param day 1970-epoch day (integral value)
+ * @param year output parameter to receive year
+ * @param month output parameter to receive month (0-based, 0==Jan)
+ * @param dom output parameter to receive day-of-month (1-based)
+ * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
+ */
+ static inline void dayToFields(double day, int32_t& year, int32_t& month,
+ int32_t& dom, int32_t& dow);
+
+ /**
+ * Convert a 1970-epoch milliseconds to proleptic Gregorian year,
+ * month, day-of-month, and day-of-week, day of year and millis-in-day.
+ * @param time 1970-epoch milliseconds
+ * @param year output parameter to receive year
+ * @param month output parameter to receive month (0-based, 0==Jan)
+ * @param dom output parameter to receive day-of-month (1-based)
+ * @param dow output parameter to receive day-of-week (1-based, 1==Sun)
+ * @param doy output parameter to receive day-of-year (1-based)
+ * @param mid output parameter to receive millis-in-day
+ */
+ static void timeToFields(UDate time, int32_t& year, int32_t& month,
+ int32_t& dom, int32_t& dow, int32_t& doy, int32_t& mid);
+
+ /**
+ * Return the day of week on the 1970-epoch day
+ * @param day the 1970-epoch day (integral value)
+ * @return the day of week
+ */
+ static int32_t dayOfWeek(double day);
+
+ /**
+ * Returns the ordinal number for the specified day of week within the month.
+ * The valid return value is 1, 2, 3, 4 or -1.
+ * @param year Gregorian year, with 0 == 1 BCE, -1 == 2 BCE, etc.
+ * @param month 0-based month, with 0==Jan
+ * @param dom 1-based day of month
+ * @return The ordinal number for the specified day of week within the month
+ */
+ static int32_t dayOfWeekInMonth(int32_t year, int32_t month, int32_t dom);
+
+ /**
+ * Converts Julian day to time as milliseconds.
+ * @param julian the given Julian day number.
+ * @return time as milliseconds.
+ * @internal
+ */
+ static inline double julianDayToMillis(int32_t julian);
+
+ /**
+ * Converts time as milliseconds to Julian day.
+ * @param millis the given milliseconds.
+ * @return the Julian day number.
+ * @internal
+ */
+ static inline int32_t millisToJulianDay(double millis);
+
+ /**
+ * Calculates the Gregorian day shift value for an extended year.
+ * @param eyear Extended year
+ * @returns number of days to ADD to Julian in order to convert from J->G
+ */
+ static inline int32_t gregorianShift(int32_t eyear);
+
+ private:
+ static const int16_t DAYS_BEFORE[24];
+ static const int8_t MONTH_LENGTH[24];
+};
+
+inline double ClockMath::floorDivide(double numerator, double denominator) {
+ return uprv_floor(numerator / denominator);
+}
+
+inline UBool Grego::isLeapYear(int32_t year) {
+ // year&0x3 == year%4
+ return ((year&0x3) == 0) && ((year%100 != 0) || (year%400 == 0));
+}
+
+inline int8_t
+Grego::monthLength(int32_t year, int32_t month) {
+ return MONTH_LENGTH[month + (isLeapYear(year) ? 12 : 0)];
+}
+
+inline int8_t
+Grego::previousMonthLength(int y, int m) {
+ return (m > 0) ? monthLength(y, m-1) : 31;
+}
+
+inline void Grego::dayToFields(double day, int32_t& year, int32_t& month,
+ int32_t& dom, int32_t& dow) {
+ int32_t doy_unused;
+ dayToFields(day,year,month,dom,dow,doy_unused);
+}
+
+inline double Grego::julianDayToMillis(int32_t julian)
+{
+ return (julian - kEpochStartAsJulianDay) * kOneDay;
+}
+
+inline int32_t Grego::millisToJulianDay(double millis) {
+ return (int32_t) (kEpochStartAsJulianDay + ClockMath::floorDivide(millis, (double)kOneDay));
+}
+
+inline int32_t Grego::gregorianShift(int32_t eyear) {
+ int64_t y = (int64_t)eyear-1;
+ int32_t gregShift = static_cast<int32_t>(ClockMath::floorDivide(y, (int64_t)400) - ClockMath::floorDivide(y, (int64_t)100) + 2);
+ return gregShift;
+}
+
+U_NAMESPACE_END
+
+#endif // !UCONFIG_NO_FORMATTING
+#endif // GREGOIMP_H
+
+//eof