- Changed the algorithm that calculates the number of days that have passed

so far as used by the the __convert_time() function and the conversion
  code in strftime().

- Also changed the algorithm used by strftime() to produce the week numbers
  (the '%U' and '%W' format specifiers). The new method is much simpler
  than the old one.

- Made the code that converts a 'time_t' value into the 'struct DateStamp',
  as used by strftime() and utime(), into its own function. This also
  fixes a bug in the code strftime() would use which was completely
  unaware of the local time zone settings.


git-svn-id: file:///Users/olsen/Code/migration-svn-zu-git/logical-line-staging/clib2/trunk@14815 87f5fb63-7c3d-0410-a384-fd976d0f7a62

library/time_days_per_date.c

@@ -0,0 +1,56 @@
+/*
+ * $Id: time_days_per_date.c,v 1.1 2005-01-29 18:05:14 obarthel Exp $
+ *
+ * :ts=4
+ *
+ * Portable ISO 'C' (1994) runtime library for the Amiga computer
+ * Copyright (c) 2002-2005 by Olaf Barthel <olsen@sourcery.han.de>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ *   - Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ *
+ *   - Neither the name of Olaf Barthel nor the names of contributors
+ *     may be used to endorse or promote products derived from this
+ *     software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/****************************************************************************/
+
+#ifndef _TIME_HEADERS_H
+#include "time_headers.h"
+#endif /* _TIME_HEADERS_H */
+
+/****************************************************************************/
+
+/* This calculates the number of days that have passed up to the
+   given date. */
+int
+__calculate_days_per_date(int year,int month,int day)
+{
+	int result;
+
+	month	= month + 9;
+	year	= year - 1 + (month / 12);
+	month	= (month % 12) * 306 + 5;
+
+	result = (year * 365) + (year / 4) - (year / 100) + (year / 400) + (month / 10) + day - 1;
+
+	return(result);
+}