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85 lines
2.6 KiB
Mathematica
85 lines
2.6 KiB
Mathematica
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/* Implementation of extension methods to standard classes
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Copyright (C) 2003 Free Software Foundation, Inc.
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Written by: Richard Frith-Macdonald <rfm@gnu.org>
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This file is part of the GNUstep Base Library.
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This library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Library General Public
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License as published by the Free Software Foundation; either
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version 2 of the License, or (at your option) any later version.
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This library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with this library; if not, write to the Free
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Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111 USA.
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*/
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#include <Foundation/Foundation.h>
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@implementation NSCalendarDate (GSCategories)
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/**
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* The ISO standard week of the year is based on the first week of the
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* year being that week (starting on monday) for which the thursday
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* is on or after the first of january.<br />
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* This has the effect that, if january first is a friday, saturday or
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* sunday, the days of that week (up to and including the sunday) are
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* considered to be in week 53 of the preceeding year. Similarly if the
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* last day of the year is a monday tuesday or wednesday, these days are
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* part of week 1 of the next year.
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*/
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- (int) weekOfYear
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{
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int dayOfWeek = [self dayOfWeek];
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int dayOfYear;
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/*
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* Whether a week is considered to be in a year or not depends on its
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* thursday ... so find thursday for the receivers week.
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* NB. this may result in a date which is not in the same year as the
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* receiver.
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*/
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if (dayOfWeek != 4)
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{
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CREATE_AUTORELEASE_POOL(arp);
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NSCalendarDate *thursday;
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/*
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* A week starts on monday ... so adjust from 0 to 7 so that a
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* sunday is counted as the last day of the week.
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*/
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if (dayOfWeek == 0)
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{
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dayOfWeek = 7;
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}
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thursday = [self dateByAddingYears: 0
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months: 0
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days: 4 - dayOfWeek
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hours: 0
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minutes: 0
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seconds: 0];
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dayOfYear = [thursday dayOfYear];
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RELEASE(arp);
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}
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else
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{
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dayOfYear = [self dayOfYear];
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}
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/*
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* Round up to a week boundary, so that when we divide by seven we
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* get a result in the range 1 to 53 as mandated by the ISO standard.
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*/
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dayOfYear += (7 - dayOfYear % 7);
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return dayOfYear / 7;
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}
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@end
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