icu4c/source/i18n/gregoimp.cpp - external/github.com/unicode-org/icu - Git at Google

 // © 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
  **********************************************************************
  */

 #include "gregoimp.h"

 #if !UCONFIG_NO_FORMATTING

 #include "unicode/ucal.h"
 #include "uresimp.h"
 #include "cstring.h"
 #include "uassert.h"

 U_NAMESPACE_BEGIN

 int32_t ClockMath::floorDivide(int32_t numerator, int32_t denominator) {
     return (numerator >= 0) ?
         numerator / denominator : ((numerator + 1) / denominator) - 1;
 }

 int64_t ClockMath::floorDivideInt64(int64_t numerator, int64_t denominator) {
     return (numerator >= 0) ?
         numerator / denominator : ((numerator + 1) / denominator) - 1;
 }

 int32_t ClockMath::floorDivide(int32_t numerator, int32_t denominator,
                           int32_t* remainder) {
     int64_t quotient = floorDivide(numerator, denominator);
     if (remainder != nullptr) {
       *remainder = numerator - (quotient * denominator);
     }
     return quotient;
 }

 double ClockMath::floorDivide(double numerator, int32_t denominator,
                           int32_t* remainder) {
     // For an integer n and representable ⌊x/n⌋, ⌊RN(x/n)⌋=⌊x/n⌋, where RN is
     // rounding to nearest.
     double quotient = uprv_floor(numerator / denominator);
     if (remainder != nullptr) {
       // For doubles x and n, where n is an integer and ⌊x+n⌋ < 2³¹, the
       // expression `(int32_t) (x + n)` evaluated with rounding to nearest
       // differs from ⌊x+n⌋ if 0 < ⌈x⌉−x ≪ x+n, as `x + n` is rounded up to
       // n+⌈x⌉ = ⌊x+n⌋ + 1.  Rewriting it as ⌊x⌋+n makes the addition exact.
       *remainder = static_cast<int32_t>(uprv_floor(numerator) - (quotient * denominator));
     }
     return quotient;
 }

 double ClockMath::floorDivide(double dividend, double divisor,
                          double* remainder) {
     // Only designed to work for positive divisors
     U_ASSERT(divisor > 0);
     double quotient = floorDivide(dividend, divisor);
     double r = dividend - (quotient * divisor);
     // N.B. For certain large dividends, on certain platforms, there
     // is a bug such that the quotient is off by one.  If you doubt
     // this to be true, set a breakpoint below and run cintltst.
     if (r < 0 || r >= divisor) {
         // E.g. 6.7317038241449352e+022 / 86400000.0 is wrong on my
         // machine (too high by one).  4.1792057231752762e+024 /
         // 86400000.0 is wrong the other way (too low).
         double q = quotient;
         quotient += (r < 0) ? -1 : +1;
         if (q == quotient) {
             // For quotients > ~2^53, we won't be able to add or
             // subtract one, since the LSB of the mantissa will be >
             // 2^0; that is, the exponent (base 2) will be larger than
             // the length, in bits, of the mantissa.  In that case, we
             // can't give a correct answer, so we set the remainder to
             // zero.  This has the desired effect of making extreme
             // values give back an approximate answer rather than
             // crashing.  For example, UDate values above a ~10^25
             // might all have a time of midnight.
             r = 0;
         } else {
             r = dividend - (quotient * divisor);
         }
     }
     U_ASSERT(0 <= r && r < divisor);
     if (remainder != nullptr) {
         *remainder = r;
     }
     return quotient;
 }

 const int32_t JULIAN_1_CE    = 1721426; // January 1, 1 CE Gregorian
 const int32_t JULIAN_1970_CE = 2440588; // January 1, 1970 CE Gregorian

 const int16_t Grego::DAYS_BEFORE[24] =
     {0,31,59,90,120,151,181,212,243,273,304,334,
      0,31,60,91,121,152,182,213,244,274,305,335};

 const int8_t Grego::MONTH_LENGTH[24] =
     {31,28,31,30,31,30,31,31,30,31,30,31,
      31,29,31,30,31,30,31,31,30,31,30,31};

 int64_t Grego::fieldsToDay(int32_t year, int32_t month, int32_t dom) {

     int64_t y = year - 1;

     int64_t julian = 365LL * y +
         ClockMath::floorDivideInt64(y, 4LL) + (JULIAN_1_CE - 3) + // Julian cal
         ClockMath::floorDivideInt64(y, 400LL) -
         ClockMath::floorDivideInt64(y, 100LL) + 2 + // => Gregorian cal
         DAYS_BEFORE[month + (isLeapYear(year) ? 12 : 0)] + dom; // => month/dom

     return julian - JULIAN_1970_CE; // JD => epoch day
 }

 void Grego::dayToFields(int32_t day, int32_t& year, int8_t& month,
                         int8_t& dom, int8_t& dow, int16_t& doy, UErrorCode& status) {
     year = dayToYear(day, doy, status); // one-based doy
     if (U_FAILURE(status)) return;

     // Convert from 1970 CE epoch to 1 CE epoch (Gregorian calendar)
     if (uprv_add32_overflow(day, JULIAN_1970_CE - JULIAN_1_CE, &day)) {
         status = U_ILLEGAL_ARGUMENT_ERROR;
         return;
     }

     // Gregorian day zero is a Monday.
     dow = (day + 1) % 7;
     dow += (dow < 0) ? (UCAL_SUNDAY + 7) : UCAL_SUNDAY;

     // Common Julian/Gregorian calculation
     int32_t correction = 0;
     bool isLeap = isLeapYear(year);
     int32_t march1 = isLeap ? 60 : 59; // zero-based DOY for March 1
     if (doy > march1) {
         correction = isLeap ? 1 : 2;
     }
     month = (12 * (doy - 1 + correction) + 6) / 367; // zero-based month
     dom = doy - DAYS_BEFORE[month + (isLeap ? 12 : 0)]; // one-based DOM
 }

 int32_t Grego::dayToYear(int32_t day, UErrorCode& status) {
     int16_t unusedDOY;
     return dayToYear(day, unusedDOY, status);
 }

 int32_t Grego::dayToYear(int32_t day, int16_t& doy, UErrorCode& status) {
     if (U_FAILURE(status)) return 0;
     // Convert from 1970 CE epoch to 1 CE epoch (Gregorian calendar)
     if (uprv_add32_overflow(day, JULIAN_1970_CE - JULIAN_1_CE, &day)) {
         status = U_ILLEGAL_ARGUMENT_ERROR;
         return 0;
     }

     // Convert from the day number to the multiple radix
     // representation.  We use 400-year, 100-year, and 4-year cycles.
     // For example, the 4-year cycle has 4 years + 1 leap day; giving
     // 1461 == 365*4 + 1 days.
     int32_t doy32;
     int32_t n400 = ClockMath::floorDivide(day, 146097, &doy32); // 400-year cycle length
     int32_t n100 = ClockMath::floorDivide(doy32, 36524, &doy32); // 100-year cycle length
     int32_t n4   = ClockMath::floorDivide(doy32, 1461, &doy32); // 4-year cycle length
     int32_t n1   = ClockMath::floorDivide(doy32, 365, &doy32);
     int32_t year = 400*n400 + 100*n100 + 4*n4 + n1;
     if (n100 == 4 || n1 == 4) {
         doy = 365; // Dec 31 at end of 4- or 400-year cycle
     } else {
         doy = doy32;
         ++year;
     }
     doy++; // one-based doy
     return year;
 }

 void Grego::dayToFields(int32_t day, int32_t& year, int8_t& month,
                         int8_t& dom, int8_t& dow, UErrorCode& status) {
     int16_t unusedDOY;
     dayToFields(day, year, month, dom, dow, unusedDOY, status);
 }

 void Grego::dayToFields(int32_t day, int32_t& year, int8_t& month,
                         int8_t& dom, int16_t& doy, UErrorCode& status) {
     int8_t unusedDOW;
     dayToFields(day, year, month, dom, unusedDOW, doy, status);
 }

 void Grego::timeToFields(UDate time, int32_t& year, int8_t& month,
                         int8_t& dom, int32_t& mid, UErrorCode& status) {
     int8_t unusedDOW;
     timeToFields(time, year, month, dom, unusedDOW, mid, status);
 }

 void Grego::timeToFields(UDate time, int32_t& year, int8_t& month,
                         int8_t& dom, int8_t& dow, int32_t& mid, UErrorCode& status) {
     int16_t unusedDOY;
     timeToFields(time, year, month, dom, dow, unusedDOY, mid, status);
 }

 void Grego::timeToFields(UDate time, int32_t& year, int8_t& month,
                         int8_t& dom, int8_t& dow, int16_t& doy, int32_t& mid, UErrorCode& status) {
     if (U_FAILURE(status)) return;
     double day = ClockMath::floorDivide(time, U_MILLIS_PER_DAY, &mid);
     if (day > INT32_MAX || day < INT32_MIN) {
         status = U_ILLEGAL_ARGUMENT_ERROR;
         return;
     }
     dayToFields(day, year, month, dom, dow, doy, status);
 }

 int32_t Grego::timeToYear(UDate time, UErrorCode& status) {
     if (U_FAILURE(status)) return 0;
     double day = ClockMath::floorDivide(time, double(U_MILLIS_PER_DAY));
     if (day > INT32_MAX || day < INT32_MIN) {
         status = U_ILLEGAL_ARGUMENT_ERROR;
         return 0;
     }
     return Grego::dayToYear(day, status);
 }

 int32_t Grego::dayOfWeek(int32_t day) {
     int32_t dow;
     ClockMath::floorDivide(day + int{UCAL_THURSDAY}, 7, &dow);
     return (dow == 0) ? UCAL_SATURDAY : dow;
 }

 int32_t Grego::dayOfWeekInMonth(int32_t year, int32_t month, int32_t dom) {
     int32_t weekInMonth = (dom + 6)/7;
     if (weekInMonth == 4) {
         if (dom + 7 > monthLength(year, month)) {
             weekInMonth = -1;
         }
     } else if (weekInMonth == 5) {
         weekInMonth = -1;
     }
     return weekInMonth;
 }

 U_NAMESPACE_END

 #endif
 //eof
	// © 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
	**********************************************************************
	*/

	#include "gregoimp.h"

	#if !UCONFIG_NO_FORMATTING

	#include "unicode/ucal.h"
	#include "uresimp.h"
	#include "cstring.h"
	#include "uassert.h"

	U_NAMESPACE_BEGIN

	int32_t ClockMath::floorDivide(int32_t numerator, int32_t denominator) {
	return (numerator >= 0) ?
	numerator / denominator : ((numerator + 1) / denominator) - 1;
	}

	int64_t ClockMath::floorDivideInt64(int64_t numerator, int64_t denominator) {
	return (numerator >= 0) ?
	numerator / denominator : ((numerator + 1) / denominator) - 1;
	}

	int32_t ClockMath::floorDivide(int32_t numerator, int32_t denominator,
	int32_t* remainder) {
	int64_t quotient = floorDivide(numerator, denominator);
	if (remainder != nullptr) {
	remainder = numerator - (quotient denominator);
	}
	return quotient;
	}

	double ClockMath::floorDivide(double numerator, int32_t denominator,
	int32_t* remainder) {
	// For an integer n and representable ⌊x/n⌋, ⌊RN(x/n)⌋=⌊x/n⌋, where RN is
	// rounding to nearest.
	double quotient = uprv_floor(numerator / denominator);
	if (remainder != nullptr) {
	// For doubles x and n, where n is an integer and ⌊x+n⌋ < 2³¹, the
	// expression `(int32_t) (x + n)` evaluated with rounding to nearest
	// differs from ⌊x+n⌋ if 0 < ⌈x⌉−x ≪ x+n, as `x + n` is rounded up to
	// n+⌈x⌉ = ⌊x+n⌋ + 1. Rewriting it as ⌊x⌋+n makes the addition exact.
	remainder = static_cast<int32_t>(uprv_floor(numerator) - (quotient denominator));
	}
	return quotient;
	}

	double ClockMath::floorDivide(double dividend, double divisor,
	double* remainder) {
	// Only designed to work for positive divisors
	U_ASSERT(divisor > 0);
	double quotient = floorDivide(dividend, divisor);
	double r = dividend - (quotient * divisor);
	// N.B. For certain large dividends, on certain platforms, there
	// is a bug such that the quotient is off by one. If you doubt
	// this to be true, set a breakpoint below and run cintltst.
	if (r < 0 \|\| r >= divisor) {
	// E.g. 6.7317038241449352e+022 / 86400000.0 is wrong on my
	// machine (too high by one). 4.1792057231752762e+024 /
	// 86400000.0 is wrong the other way (too low).
	double q = quotient;
	quotient += (r < 0) ? -1 : +1;
	if (q == quotient) {
	// For quotients > ~2^53, we won't be able to add or
	// subtract one, since the LSB of the mantissa will be >
	// 2^0; that is, the exponent (base 2) will be larger than
	// the length, in bits, of the mantissa. In that case, we
	// can't give a correct answer, so we set the remainder to
	// zero. This has the desired effect of making extreme
	// values give back an approximate answer rather than
	// crashing. For example, UDate values above a ~10^25
	// might all have a time of midnight.
	r = 0;
	} else {
	r = dividend - (quotient * divisor);
	}
	}
	U_ASSERT(0 <= r && r < divisor);
	if (remainder != nullptr) {
	*remainder = r;
	}
	return quotient;
	}

	const int32_t JULIAN_1_CE = 1721426; // January 1, 1 CE Gregorian
	const int32_t JULIAN_1970_CE = 2440588; // January 1, 1970 CE Gregorian

	const int16_t Grego::DAYS_BEFORE[24] =
	{0,31,59,90,120,151,181,212,243,273,304,334,
	0,31,60,91,121,152,182,213,244,274,305,335};

	const int8_t Grego::MONTH_LENGTH[24] =
	{31,28,31,30,31,30,31,31,30,31,30,31,
	31,29,31,30,31,30,31,31,30,31,30,31};

	int64_t Grego::fieldsToDay(int32_t year, int32_t month, int32_t dom) {

	int64_t y = year - 1;

	int64_t julian = 365LL * y +
	ClockMath::floorDivideInt64(y, 4LL) + (JULIAN_1_CE - 3) + // Julian cal
	ClockMath::floorDivideInt64(y, 400LL) -
	ClockMath::floorDivideInt64(y, 100LL) + 2 + // => Gregorian cal
	DAYS_BEFORE[month + (isLeapYear(year) ? 12 : 0)] + dom; // => month/dom

	return julian - JULIAN_1970_CE; // JD => epoch day
	}

	void Grego::dayToFields(int32_t day, int32_t& year, int8_t& month,
	int8_t& dom, int8_t& dow, int16_t& doy, UErrorCode& status) {
	year = dayToYear(day, doy, status); // one-based doy
	if (U_FAILURE(status)) return;

	// Convert from 1970 CE epoch to 1 CE epoch (Gregorian calendar)
	if (uprv_add32_overflow(day, JULIAN_1970_CE - JULIAN_1_CE, &day)) {
	status = U_ILLEGAL_ARGUMENT_ERROR;
	return;
	}

	// Gregorian day zero is a Monday.
	dow = (day + 1) % 7;
	dow += (dow < 0) ? (UCAL_SUNDAY + 7) : UCAL_SUNDAY;

	// Common Julian/Gregorian calculation
	int32_t correction = 0;
	bool isLeap = isLeapYear(year);
	int32_t march1 = isLeap ? 60 : 59; // zero-based DOY for March 1
	if (doy > march1) {
	correction = isLeap ? 1 : 2;
	}
	month = (12 * (doy - 1 + correction) + 6) / 367; // zero-based month
	dom = doy - DAYS_BEFORE[month + (isLeap ? 12 : 0)]; // one-based DOM
	}

	int32_t Grego::dayToYear(int32_t day, UErrorCode& status) {
	int16_t unusedDOY;
	return dayToYear(day, unusedDOY, status);
	}

	int32_t Grego::dayToYear(int32_t day, int16_t& doy, UErrorCode& status) {
	if (U_FAILURE(status)) return 0;
	// Convert from 1970 CE epoch to 1 CE epoch (Gregorian calendar)
	if (uprv_add32_overflow(day, JULIAN_1970_CE - JULIAN_1_CE, &day)) {
	status = U_ILLEGAL_ARGUMENT_ERROR;
	return 0;
	}

	// Convert from the day number to the multiple radix
	// representation. We use 400-year, 100-year, and 4-year cycles.
	// For example, the 4-year cycle has 4 years + 1 leap day; giving
	// 1461 == 365*4 + 1 days.
	int32_t doy32;
	int32_t n400 = ClockMath::floorDivide(day, 146097, &doy32); // 400-year cycle length
	int32_t n100 = ClockMath::floorDivide(doy32, 36524, &doy32); // 100-year cycle length
	int32_t n4 = ClockMath::floorDivide(doy32, 1461, &doy32); // 4-year cycle length
	int32_t n1 = ClockMath::floorDivide(doy32, 365, &doy32);
	int32_t year = 400n400 + 100n100 + 4*n4 + n1;
	if (n100 == 4 \|\| n1 == 4) {
	doy = 365; // Dec 31 at end of 4- or 400-year cycle
	} else {
	doy = doy32;
	++year;
	}
	doy++; // one-based doy
	return year;
	}

	void Grego::dayToFields(int32_t day, int32_t& year, int8_t& month,
	int8_t& dom, int8_t& dow, UErrorCode& status) {
	int16_t unusedDOY;
	dayToFields(day, year, month, dom, dow, unusedDOY, status);
	}

	void Grego::dayToFields(int32_t day, int32_t& year, int8_t& month,
	int8_t& dom, int16_t& doy, UErrorCode& status) {
	int8_t unusedDOW;
	dayToFields(day, year, month, dom, unusedDOW, doy, status);
	}

	void Grego::timeToFields(UDate time, int32_t& year, int8_t& month,
	int8_t& dom, int32_t& mid, UErrorCode& status) {
	int8_t unusedDOW;
	timeToFields(time, year, month, dom, unusedDOW, mid, status);
	}

	void Grego::timeToFields(UDate time, int32_t& year, int8_t& month,
	int8_t& dom, int8_t& dow, int32_t& mid, UErrorCode& status) {
	int16_t unusedDOY;
	timeToFields(time, year, month, dom, dow, unusedDOY, mid, status);
	}

	void Grego::timeToFields(UDate time, int32_t& year, int8_t& month,
	int8_t& dom, int8_t& dow, int16_t& doy, int32_t& mid, UErrorCode& status) {
	if (U_FAILURE(status)) return;
	double day = ClockMath::floorDivide(time, U_MILLIS_PER_DAY, &mid);
	if (day > INT32_MAX \|\| day < INT32_MIN) {
	status = U_ILLEGAL_ARGUMENT_ERROR;
	return;
	}
	dayToFields(day, year, month, dom, dow, doy, status);
	}

	int32_t Grego::timeToYear(UDate time, UErrorCode& status) {
	if (U_FAILURE(status)) return 0;
	double day = ClockMath::floorDivide(time, double(U_MILLIS_PER_DAY));
	if (day > INT32_MAX \|\| day < INT32_MIN) {
	status = U_ILLEGAL_ARGUMENT_ERROR;
	return 0;
	}
	return Grego::dayToYear(day, status);
	}

	int32_t Grego::dayOfWeek(int32_t day) {
	int32_t dow;
	ClockMath::floorDivide(day + int{UCAL_THURSDAY}, 7, &dow);
	return (dow == 0) ? UCAL_SATURDAY : dow;
	}

	int32_t Grego::dayOfWeekInMonth(int32_t year, int32_t month, int32_t dom) {
	int32_t weekInMonth = (dom + 6)/7;
	if (weekInMonth == 4) {
	if (dom + 7 > monthLength(year, month)) {
	weekInMonth = -1;
	}
	} else if (weekInMonth == 5) {
	weekInMonth = -1;
	}
	return weekInMonth;
	}

	U_NAMESPACE_END

	#endif
	//eof