/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
*
* This code is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 only, as
* published by the Free Software Foundation. Oracle designates this
* particular file as subject to the "Classpath" exception as provided
* by Oracle in the LICENSE file that accompanied this code.
*
* This code is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
* version 2 for more details (a copy is included in the LICENSE file that
* accompanied this code).
*
* You should have received a copy of the GNU General Public License version
* 2 along with this work; if not, write to the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
* or visit www.oracle.com if you need additional information or have any
* questions.
*/
/*
* Copyright (c) 2009-2012, Stephen Colebourne & Michael Nascimento Santos
*
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
*
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* * Neither the name of JSR-310 nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
package build.tools.tzdb;
import java.util.Objects;
class Utils {
// Returns the largest (closest to positive infinity)
public static long floorDiv(long x, long y) {
long r = x / y;
// if the signs are different and modulo not zero, round down
if ((x ^ y) < 0 && (r * y != x)) {
r--;
}
return r;
}
// Returns the floor modulus of the {@code long} arguments.
public static long floorMod(long x, long y) {
return x - floorDiv(x, y) * y;
}
// Returns the sum of its arguments,
public static long addExact(long x, long y) {
long r = x + y;
// HD 2-12 Overflow iff both arguments have the opposite sign of the result
if (((x ^ r) & (y ^ r)) < 0) {
throw new ArithmeticException("long overflow");
}
return r;
}
// Year
// Returns true if the specified year is a leap year.
public static boolean isLeapYear(int year) {
return ((year & 3) == 0) && ((year % 100) != 0 || (year % 400) == 0);
}
// The minimum supported year, '-999,999,999'.
public static final int YEAR_MIN_VALUE = -999_999_999;
// The maximum supported year, '+999,999,999'.
public static final int YEAR_MAX_VALUE = 999_999_999;
// Gets the length of the specified month in days.
public static int lengthOfMonth(int month, boolean leapYear) {
switch (month) {
case 2: //FEBRUARY:
return (leapYear ? 29 : 28);
case 4: //APRIL:
case 6: //JUNE:
case 9: //SEPTEMBER:
case 11: //NOVEMBER:
return 30;
default:
return 31;
}
}
// Gets the maximum length of the specified month in days.
public static int maxLengthOfMonth(int month) {
switch (month) {
case 2: //FEBRUARY:
return 29;
case 4: //APRIL:
case 6: //JUNE:
case 9: //SEPTEMBER:
case 11: //NOVEMBER:
return 30;
default:
return 31;
}
}
// DayOfWeek
// Returns the day-of-week that is the specified number of days after
// this one, from 1 to 7 for Monday to Sunday.
public static int plusDayOfWeek(int dow, long days) {
int amount = (int) (days % 7);
return (dow - 1 + (amount + 7)) % 7 + 1;
}
// Returns the day-of-week that is the specified number of days before
// this one, from 1 to 7 for Monday to Sunday.
public static int minusDayOfWeek(int dow, long days) {
return plusDayOfWeek(dow, -(days % 7));
}
// Adjusts the date to the first occurrence of the specified day-of-week
// before the date being adjusted unless it is already on that day in
// which case the same object is returned.
public static LocalDate previousOrSame(LocalDate date, int dayOfWeek) {
return adjust(date, dayOfWeek, 1);
}
// Adjusts the date to the first occurrence of the specified day-of-week
// after the date being adjusted unless it is already on that day in
// which case the same object is returned.
public static LocalDate nextOrSame(LocalDate date, int dayOfWeek) {
return adjust(date, dayOfWeek, 0);
}
// Implementation of next, previous or current day-of-week.
// @param relative whether the current date is a valid answer
private static final LocalDate adjust(LocalDate date, int dow, int relative) {
int calDow = date.getDayOfWeek();
if (relative < 2 && calDow == dow) {
return date;
}
if ((relative & 1) == 0) {
int daysDiff = calDow - dow;
return date.plusDays(daysDiff >= 0 ? 7 - daysDiff : -daysDiff);
} else {
int daysDiff = dow - calDow;
return date.minusDays(daysDiff >= 0 ? 7 - daysDiff : -daysDiff);
}
}
}