40 lines
745 B
C
40 lines
745 B
C
/* $NetBSD: ymd2yd.c,v 1.1.1.1 2000/03/29 12:38:50 simonb Exp $ */
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/*
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* ymd2yd - compute the date in the year from y/m/d
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*/
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#include "ntp_fp.h"
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#include "ntp_unixtime.h"
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#include "ntp_stdlib.h"
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/*
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* Tables to compute the day of year from yyyymmdd timecode.
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* Viva la leap.
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*/
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static int day1tab[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
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static int day2tab[] = {31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
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int
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ymd2yd(
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int y,
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int m,
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int d
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)
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{
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int i, *t;
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if (m < 1 || m > 12 || d < 1)
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return (-1);
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if (((y%4 == 0) && (y%100 != 0)) || (y%400 == 0))
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t = day2tab; /* leap year */
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else
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t = day1tab; /* not a leap year */
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if (d > t[m - 1])
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return (-1);
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for (i = 0; i < m - 1; i++)
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d += t[i];
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return d;
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}
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