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1ab8939077
The implementation in LibC did a timestamp->day-of-week conversion which looks like a valuable thing to have. But we only need it in time_to_tm, where we already computed year/month/day -- so let's consolidate on the day_of_week function in DateTime (which is getting extracted to AK).
64 lines
2.4 KiB
C++
64 lines
2.4 KiB
C++
/*
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* Copyright (c) 2020, The SerenityOS developers.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* 2. Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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* DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
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* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <AK/Assertions.h>
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#include <AK/Time.h>
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namespace AK {
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int day_of_year(int year, unsigned month, int day)
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{
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ASSERT(month >= 1 && month <= 12);
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static const int seek_table[] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
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int day_of_year = seek_table[month - 1] + day - 1;
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if (is_leap_year(year) && month >= 3)
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day_of_year++;
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return day_of_year;
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}
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int days_in_month(int year, unsigned month)
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{
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ASSERT(month >= 1 && month <= 12);
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if (month == 2)
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return is_leap_year(year) ? 29 : 28;
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bool is_long_month = (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12);
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return is_long_month ? 31 : 30;
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}
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unsigned day_of_week(int year, unsigned month, int day)
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{
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ASSERT(month >= 1 && month <= 12);
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static const int seek_table[] = { 0, 3, 2, 5, 0, 3, 5, 1, 4, 6, 2, 4 };
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if (month < 3)
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--year;
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return (year + year / 4 - year / 100 + year / 400 + seek_table[month - 1] + day) % 7;
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}
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}
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