From acec689ef648adaa5c420049bfb775953e184bda Mon Sep 17 00:00:00 2001
From: Sergey Poznyakoff <gray@gnu.org.ua>
Date: Thu, 8 Dec 2011 17:04:29 +0200
Subject: Revamp date/time calculations.

* configure.ac: Build libmailutils/datetime/Makefile.am
* include/mailutils/datetime.h (mu_datetime_julianday)
(mu_datetime_dayofweek,mu_datetime_dayofyear)
(mu_datetime_year_days): New protos.
* libmailutils/Makefile.am (SUBDIRS): Add datetime
(libmailutils_la_LIBADD): Add libdatetime.la
* libmailutils/base/Makefile.am (libbase_la_SOURCES): Remove date.c
and strftime.c.
* libmailutils/base/date.c: Remove.
* libmailutils/base/strftime.c: Move to libmailutils/datetime
* libmailutils/datetime/Makefile.am: New file.
* libmailutils/datetime/dow.c: New file.
* libmailutils/datetime/doy.c: New file.
* libmailutils/datetime/jd.c: New file.
* libmailutils/datetime/scantime.c: New file.
* libmailutils/datetime/streamftime.c: New file.
* libmailutils/datetime/tab.c: New file.
* libmailutils/datetime/unixtime.c: New file.
* libmailutils/datetime/utcoff.c: New file.
* libmailutils/datetime/yd.c: New file.
* libmailutils/tests/scantime.at: Fix yday numbers.
---
 libmailutils/datetime/doy.c | 53 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)
 create mode 100644 libmailutils/datetime/doy.c

(limited to 'libmailutils/datetime/doy.c')

diff --git a/libmailutils/datetime/doy.c b/libmailutils/datetime/doy.c
new file mode 100644
index 000000000..49883cd32
--- /dev/null
+++ b/libmailutils/datetime/doy.c
@@ -0,0 +1,53 @@
+/* GNU Mailutils -- a suite of utilities for electronic mail
+   Copyright (C) 2011 Free Software Foundation, Inc.
+
+   This library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 3 of the License, or (at your option) any later version.
+
+   This library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General
+   Public License along with this library.  If not, see
+   <http://www.gnu.org/licenses/>. */
+
+#ifdef HAVE_CONFIG_H
+# include <config.h>
+#endif
+#include <stdlib.h>
+#include <mailutils/datetime.h>
+
+static int  month_start[]=
+    {    0, 31, 59,  90, 120, 151, 181, 212, 243, 273, 304, 334, 365 };
+     /* Jan Feb Mar  Apr  May  Jun  Jul  Aug  Sep  Oct  Nov  Dec
+         31  28  31   30   31   30   31   31   30   31   30   31
+     */
+
+#define leap_year(y) ((y) % 4 == 0 && ((y) % 100 != 0 || (y) % 400 == 0))
+
+/* Compute number of days since January 1 to the given day of year. */
+int
+mu_datetime_dayofyear (int year, int month, int day)
+{
+  int  leap, month_days;
+
+  if (year < 0 || month < 1 || month > 12 || day < 1)
+    return -1;
+    
+  leap = leap_year (year);
+  
+  month_days = month_start[month] - month_start[month - 1]
+               + ((month == 2) ? leap : 0);
+
+  if (day > month_days)
+    return -1;
+
+  if (month <= 2)
+    leap = 0;
+
+  return month_start[month-1] + day + leap;
+}
-- 
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