5e53a4f90f
Mainly focus on files that use BSD 2-Clause license, however the tool I was using mis-identified many licenses so this was mostly a manual - error prone - task. The Software Package Data Exchange (SPDX) group provides a specification to make it easier for automated tools to detect and summarize well known opensource licenses. We are gradually adopting the specification, noting that the tags are considered only advisory and do not, in any way, superceed or replace the license texts.
104 lines
2.9 KiB
C
104 lines
2.9 KiB
C
/*-
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* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
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*
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* Copyright (c) 1997 Wolfgang Helbig
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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
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* 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
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR 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
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include "calendar.h"
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typedef struct date date;
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static int easterodn(int y);
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/* Compute Easter Sunday in Gregorian Calendar */
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date *
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easterg(int y, date *dt)
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{
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int c, i, j, k, l, n;
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n = y % 19;
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c = y / 100;
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k = (c - 17) / 25;
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i = (c - c/4 -(c-k)/3 + 19 * n + 15) % 30;
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i = i -(i/28) * (1 - (i/28) * (29/(i + 1)) * ((21 - n)/11));
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j = (y + y/4 + i + 2 - c + c/4) % 7;
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l = i - j;
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dt->m = 3 + (l + 40) / 44;
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dt->d = l + 28 - 31*(dt->m / 4);
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dt->y = y;
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return (dt);
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}
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/* Compute the Gregorian date of Easter Sunday in Julian Calendar */
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date *
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easterog(int y, date *dt)
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{
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return (gdate(easterodn(y), dt));
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}
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/* Compute the Julian date of Easter Sunday in Julian Calendar */
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date *
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easteroj(int y, date * dt)
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{
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return (jdate(easterodn(y), dt));
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}
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/* Compute the day number of Easter Sunday in Julian Calendar */
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static int
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easterodn(int y)
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{
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/*
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* Table for the easter limits in one metonic (19-year) cycle. 21
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* to 31 is in March, 1 through 18 in April. Easter is the first
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* sunday after the easter limit.
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*/
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int mc[] = {5, 25, 13, 2, 22, 10, 30, 18, 7, 27, 15, 4,
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24, 12, 1, 21, 9, 29, 17};
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/* Offset from a weekday to next sunday */
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int ns[] = {6, 5, 4, 3, 2, 1, 7};
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date dt;
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int dn;
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/* Assign the easter limit of y to dt */
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dt.d = mc[y % 19];
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if (dt.d < 21)
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dt.m = 4;
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else
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dt.m = 3;
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dt.y = y;
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/* Return the next sunday after the easter limit */
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dn = ndaysj(&dt);
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return (dn + ns[weekday(dn)]);
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}
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