Merge branch 'juldat_rework' of https://github.com/tapkey/libical into tapkey-juldat_rework

5 files changed, 302 insertions, 22 deletions

diff --git a/ReleaseNotes.txt b/ReleaseNotes.txt
index 382c8aec..655a574a 100644
--- a/ReleaseNotes.txt
+++ b/ReleaseNotes.txt
@@ -8,6 +8,9 @@ Version 3.1.0:
      + icalrecurrencetype_encode_month
      + icaltzutil_set_zone_directory
  * icaltzutil_get_zone_directory() can use the TZDIR environment to find system zoneinfo
+ * Deprecated functions:
+     + caldat
+     + juldat
 
 Version 3.0.4:
 --------------
diff --git a/src/libical/astime.h b/src/libical/astime.h
index b8710b28..4a01c53c 100644
--- a/src/libical/astime.h
+++ b/src/libical/astime.h
@@ -1,3 +1,7 @@
+/* 
+ * This work is based on work from Hiram Clawson and has been modified to the
+ * needs of the libical project. The original copyright notice is as follows:
+ */
 /*
  *      Copyright (c) 1986-2000, Hiram Clawson
  *      All rights reserved.
@@ -33,6 +37,27 @@
  *      IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  *      THE POSSIBILITY OF SUCH DAMAGE.
  */
+/*
+ * The modifications made are licensed as follows (to distinguish between
+ * the original code and the modifications made, refer to the source code
+ * history):
+ */
+ /*======================================================================
+
+  (C) COPYRIGHT 2018, Markus Minichmayr
+      https://tapkey.com
+
+  This library is free software; you can redistribute it and/or modify
+  it under the terms of either:
+
+     The LGPL as published by the Free Software Foundation, version
+     2.1, available at: http://www.gnu.org/licenses/lgpl-2.1.html
+
+  Or:
+
+     The Mozilla Public License Version 2.0. You may obtain a copy of
+     the License at http://www.mozilla.org/MPL/
+ ========================================================================*/
 
 /**
  *      @file astime.h
@@ -62,8 +87,33 @@ typedef struct ut_instant
 
 /*      Functions in caldate.c  */
 
-LIBICAL_ICAL_EXPORT long caldat(UTinstantPtr);      /** converts julian date to year,mo,da */
+/** converts julian date to year,mo,da
+ *  @deprecated use caldat_int() instead

+ */

+LIBICAL_ICAL_EXPORT long caldat(UTinstantPtr);
+
+/** returns julian day from year,mo,da
+ *  @deprecated use juldat_int() instead

+ */

+LIBICAL_ICAL_EXPORT double juldat(UTinstantPtr);
+
+
+typedef struct ut_instant_int
+{
+    long j_date0;      /**< julian decimal date, 0 = 01 Jan 4713 BC */
+    long year;          /**< year, valid range [-4,713, +32,767] */
+    int month;          /**<    [1-12]  */
+    int day;            /**<    [1-31]  */
+    int weekday;                /**<    [0-6]   */
+    int day_of_year;            /**<    [1-366] */
+} UTinstantInt, *UTinstantIntPtr;
+
+/*      Functions in caldate.c  */
+
+/** converts julian date to year,mo,da */
+void caldat_int(UTinstantIntPtr);
 
-LIBICAL_ICAL_EXPORT double juldat(UTinstantPtr);    /** returns julian day from year,mo,da */
+/** returns julian day from year,mo,da */
+void juldat_int(UTinstantIntPtr);
 
 #endif
diff --git a/src/libical/caldate.c b/src/libical/caldate.c
index 086e0591..726fffc7 100644
--- a/src/libical/caldate.c
+++ b/src/libical/caldate.c
@@ -1,4 +1,8 @@
 /*
+ * This work is based on work from Hiram Clawson and has been modified to the
+ * needs of the libical project. The original copyright notice is as follows:
+ */
+/*
  *	Copyright (c) 1986-2000, Hiram Clawson 
  *	All rights reserved.
  *
@@ -33,6 +37,28 @@
  *	IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  *	THE POSSIBILITY OF SUCH DAMAGE. 
  */
+/*
+ * The modifications made are licensed as follows (to distinguish between
+ * the original code and the modifications made, refer to the source code
+ * history):
+ */
+/*======================================================================
+
+   (C) COPYRIGHT 2018, Markus Minichmayr
+       https://tapkey.com
+
+   This library is free software; you can redistribute it and/or modify
+   it under the terms of either:
+
+      The LGPL as published by the Free Software Foundation, version
+      2.1, available at: http://www.gnu.org/licenses/lgpl-2.1.html
+
+   Or:
+
+      The Mozilla Public License Version 2.0. You may obtain a copy of
+      the License at http://www.mozilla.org/MPL/
+  ========================================================================*/
+
 
 #include "astime.h"	/*	time structures	*/
 
@@ -175,3 +201,127 @@ struct ut_instant * date;
 	date->weekday = (jd + 1L) % 7L;
 	return( date->j_date );
 }	/*	end of	double juldat( date )	*/
+
+
+/**
+ *	caldat computes the day of the week, the day of the year
+ *	the gregorian (or julian) calendar date
+ *	from the julian decimal date.
+ *	for astronomical purposes, The Gregorian calendar reform occurred
+ *	on 15 Oct. 1582.  This is 05 Oct 1582 by the julian calendar.
+
+ *	Input:	a ut_instant structure pointer, where the j_date element
+ *		has been set. ( = 0 for 01 Jan 4713 B.C.)
+ *
+ *	output:  will set all the other elements of the structure.
+ *		As a convienence, the function will also return the year.
+ *
+ *	Reference: Astronomial formulae for calculators, meeus, p 23
+ *	from fortran program by F. Espenak - April 1982 Page 277,
+ *	50 Year canon of solar eclipses: 1986-2035
+ *
+ */
+
+void caldat_int( date )
+struct ut_instant_int * date;
+{
+	long jd;
+	long ka;
+	long kb;
+	long kc;
+	long kd;
+	long ke;
+	long ialp;
+
+	jd = (long) (date->j_date0 + 1L);	/* integer julian date */
+	ka = (long) jd;
+	if ( jd >= 2299161L )
+	{
+            ialp = (long) (((jd * 100LL) - 186721625LL) / 3652425LL);
+            ka = jd + 1L + ialp - ( ialp >> 2 );
+	}
+	kb = ka + 1524L;
+	kc = (long) ( ((kb * 100LL) - 12210LL) / 36525LL );
+	kd = (long) ( ( kc * 36525LL ) / 100LL );
+	ke = (long) ( (kb - kd) * 10000LL / 306001LL );
+	date->day = kb - kd - ((long) ( (ke * 306001LL) / 10000LL ));
+	if ( ke > 13L )
+		date->month = ke - 13L;
+	else
+		date->month = ke - 1L;
+	if ( (date->month == 2) && (date->day > 28) )
+		date->day = 29;
+	if ( (date->month == 2) && (date->day == 29) && (ke == 3L) )
+		date->year = kc - 4716L;
+	else if ( date->month > 2 )
+		date->year = kc - 4716L;
+	else
+		date->year = kc - 4715L;
+	date->weekday = (jd + 1L) % 7L;	/* day of week */
+	if ( date->year == ((date->year >> 2) << 2) )
+		date->day_of_year =
+			( ( 275 * date->month ) / 9)
+			- ((date->month + 9) / 12)
+			+ date->day - 30;
+	else
+		date->day_of_year =
+			( ( 275 * date->month ) / 9)
+			- (((date->month + 9) / 12) << 1)
+			+ date->day - 30;
+}
+
+/**
+ *	juldat computes the julian decimal date (j_date) from
+ *	the gregorian (or Julian) calendar date.
+ *	for astronomical purposes, The Gregorian calendar reform occurred
+ *	on 15 Oct. 1582.  This is 05 Oct 1582 by the julian calendar.
+ *	Input:  a ut_instant structure pointer where Day, Month, Year
+ *      have been set for the date in question.
+ *
+ *	Output: the j_date and weekday elements of the structure will be set.
+ *		Also, the return value of the function will be the j_date too.
+ *
+ *	Reference: Astronomial formulae for calculators, meeus, p 23
+ *	from fortran program by F. Espenak - April 1982 Page 276,
+ *	50 Year canon of solar eclipses: 1986-2035
+ */
+
+void juldat_int( date )
+struct ut_instant_int * date;
+{
+	long iy0, im0;
+	long ia, ib;
+	long jd;
+
+	/* conversion factors */
+	if ( date->month <= 2 )
+	{
+		iy0 = date->year - 1L;
+		im0 = date->month + 12;
+	}
+	else
+	{
+		iy0 = date->year;
+		im0 = date->month;
+	}
+	ia = iy0 / 100L;
+	ib = 2L - ia + (ia >> 2);
+	/* calculate julian date	*/
+	if ( date->year < 0L )
+		jd = (long) (((36525LL * iy0) - 75) / 100)
+			+ (long) ((306001LL * (im0 + 1L)) / 10000)
+			+ (long) date->day + 1720994L;
+	else
+		jd = (long) ((36525LL * iy0) / 100)
+			+ (long) ((306001LL * (im0 + 1L)) / 10000)
+			+ (long) date->day + 1720994L;
+
+	/* on or after 15 October 1582	*/
+	if ((date->year > 1582)
+			|| ((date->year == 1582) && (((date->month * 100) + date->day) >= 1015))
+		) {
+		jd += ib;
+	}
+	date->j_date0 = jd;
+	date->weekday = (jd + 2L) % 7L;
+}	/*	end of	void juldat( date )	*/
diff --git a/src/libical/icaltime.c b/src/libical/icaltime.c
index cace5eb9..e978a991 100644
--- a/src/libical/icaltime.c
+++ b/src/libical/icaltime.c
@@ -526,18 +526,15 @@ int icaltime_days_in_month(const int month, const int year)
 /* 1-> Sunday, 7->Saturday */
 int icaltime_day_of_week(const struct icaltimetype t)
 {
-    UTinstant jt;
+    UTinstantInt jt;
 
-    memset(&jt, 0, sizeof(UTinstant));
+    memset(&jt, 0, sizeof(UTinstantInt));
 
     jt.year = t.year;
     jt.month = t.month;
     jt.day = t.day;
-    jt.i_hour = 0;
-    jt.i_minute = 0;
-    jt.i_second = 0;
 
-    (void)juldat(&jt);
+    (void)juldat_int(&jt);
 
     return jt.weekday + 1;
 }
@@ -546,20 +543,17 @@ int icaltime_day_of_week(const struct icaltimetype t)
  */
 int icaltime_start_doy_week(const struct icaltimetype t, int fdow)
 {
-    UTinstant jt;
+    UTinstantInt jt;
     int delta;
 
-    memset(&jt, 0, sizeof(UTinstant));
+    memset(&jt, 0, sizeof(UTinstantInt));
 
     jt.year = t.year;
     jt.month = t.month;
     jt.day = t.day;
-    jt.i_hour = 0;
-    jt.i_minute = 0;
-    jt.i_second = 0;
 
-    (void)juldat(&jt);
-    (void)caldat(&jt);
+    (void)juldat_int(&jt);
+    (void)caldat_int(&jt);
 
     delta = jt.weekday - (fdow - 1);
     if (delta < 0) {
@@ -574,19 +568,16 @@ int icaltime_start_doy_week(const struct icaltimetype t, int fdow)
  */
 int icaltime_week_number(const struct icaltimetype ictt)
 {
-    UTinstant jt;
+    UTinstantInt jt;
 
-    memset(&jt, 0, sizeof(UTinstant));
+    memset(&jt, 0, sizeof(UTinstantInt));
 
     jt.year = ictt.year;
     jt.month = ictt.month;
     jt.day = ictt.day;
-    jt.i_hour = 0;
-    jt.i_minute = 0;
-    jt.i_second = 0;
 
-    (void)juldat(&jt);
-    (void)caldat(&jt);
+    (void)juldat_int(&jt);
+    (void)caldat_int(&jt);
 
     return (jt.day_of_year - jt.weekday) / 7;
 }
diff --git a/src/test/regression.c b/src/test/regression.c
index 21557199..ddb2f2bd 100644
--- a/src/test/regression.c
+++ b/src/test/regression.c
@@ -25,6 +25,7 @@
 #endif
 
 #include "regression.h"
+#include "libical/astime.h"
 #include "libical/ical.h"
 #include "libicalss/icalss.h"
 #include "libicalvcal/icalvcal.h"
@@ -2666,6 +2667,90 @@ void test_recur_parser()
     str_is(str, icalrecurrencetype_as_string(&rt), str);
 }
 
+
+static int test_juldat_caldat_instance(long year, int month, int day) {
+
+    struct icaltimetype t;
+    struct ut_instant originalInstant;
+
+    
+    memset(&t, 0, sizeof(t));
+    t.year = year;
+    t.month = month;
+    t.day = day;
+
+    memset(&originalInstant, 0, sizeof(originalInstant));
+    originalInstant.year = year;
+    originalInstant.month = month;
+    originalInstant.day = day;
+
+    juldat(&originalInstant);
+    caldat(&originalInstant);
+
+    if (icaltime_day_of_week(t) != originalInstant.weekday + 1)
+        return -1;
+
+    if (icaltime_start_doy_week(t, 1) != originalInstant.day_of_year - originalInstant.weekday)
+        return -1;
+
+    if (icaltime_week_number(t) != (originalInstant.day_of_year - originalInstant.weekday) / 7)
+        return -1;
+
+    return 0;
+}
+
+/*
+ * This test verifies the caldat_int and juldat_int functions. The functions are reworked versions 
+ * of the original caldat and juldat functions but avoid using floating point arithmetics. As the
+ * new functions are not exported, the test cannot access them directly. It therefore checks the
+ * output of the icaltime_day_of_week, icaltime_start_doy_week and icaltime_week_number functions
+ * which are based on the functions to be tested.
+ */
+void test_juldat_caldat() {
+
+    int i;
+    int failed = 0;
+
+    ok("juldat and caldat return the expected values for specified min input values", test_juldat_caldat_instance(-4713, 1, 1) == 0);
+    ok("juldat and caldat return the expected values for specified max input values", test_juldat_caldat_instance(+32767, 12, 31) == 0);
+
+    ok("juldat and caldat return the expected values before end of julian calendar", test_juldat_caldat_instance(1582, 10, 4) == 0);
+    ok("juldat and caldat return the expected values at end of julian calendar", test_juldat_caldat_instance(1582, 10, 5) == 0);
+    ok("juldat and caldat return the expected values before introduction of gregorian calendar", test_juldat_caldat_instance(1582, 10, 14) == 0);
+    ok("juldat and caldat return the expected values at introduction of gregorian calendar", test_juldat_caldat_instance(1582, 10, 15) == 0);
+    ok("juldat and caldat return the expected values after introduction of gregorian calendar", test_juldat_caldat_instance(1582, 10, 16) == 0);
+
+    for (i = 0; i < 2582; i++) {
+
+        long y = i;
+
+        failed |= (test_juldat_caldat_instance(y, 1, 1) != 0);
+        failed |= (test_juldat_caldat_instance(y, 2, 28) != 0);
+
+        // Not every year has a leap day, but juldat_int/caldat_int should still produce
+        // the same output as the original implementation.
+        failed |= (test_juldat_caldat_instance(y, 2, 29) != 0);
+        failed |= (test_juldat_caldat_instance(y, 3, 1) != 0);
+        failed |= (test_juldat_caldat_instance(y, 12, 31) != 0);
+    }
+    ok("juldat and caldat return the expected values for random input values", failed == 0);
+
+    failed = 0;
+    for (i = 0; i < 10000; i++) {
+        long y = rand() % 2582;
+        int m = rand() % 12 + 1;
+
+        // Might produce some invalid dates, but juldat_int/caldat_int should still produce
+        // the same output as the original implementation.
+        int d = rand() % 31 + 1;
+
+        failed |= (test_juldat_caldat_instance(y, m, d) != 0);
+    }
+
+    ok("juldat and caldat return the expected values for random input values", failed == 0);
+}
+
+
 char *ical_strstr(const char *haystack, const char *needle)
 {
     return strstr(haystack, needle);
@@ -4367,6 +4452,7 @@ int main(int argc, char *argv[])
 
     test_run("Test time parser functions", test_time_parser, do_test, do_header);
     test_run("Test time", test_time, do_test, do_header);
+    test_run("Test calculation of DOY and WD", test_juldat_caldat, do_test, do_header);
     test_run("Test day of Year", test_doy, do_test, do_header);
     test_run("Test duration", test_duration, do_test, do_header);
     test_run("Test period", test_period, do_test, do_header);