Add support for ordinal date formats.

src/libiso8601/calc.c

@@ -69,10 +69,9 @@ static const struct monthcount _days_in_month_leap[] = {
 
 
 
-void iso8601_to_cal(int* year, int* month, int* day, const struct iso8601_date* date)
+static void _to_year(int* year, int* days_left, const struct iso8601_date* date)
 {
     div_t qr;
-    const struct monthcount* mc;
     int ndays = date->day;
 
     // Each 400 years have 97 leap days, giving 365*400+97 = 146097 days in 400 years
@@ -111,6 +110,19 @@ void iso8601_to_cal(int* year, int* month, int* day, const struct iso8601_date*
         ndays = qr.rem;
     }
 
+    *days_left = ndays;
+}
+
+
+
+void iso8601_to_cal(int* year, int* month, int* day, const struct iso8601_date* date)
+{
+    const struct monthcount* mc;
+    int ndays;
+
+    // perform year calulation
+    _to_year(year, &ndays, date);
+
     // now we simply have number of days elapsed since day 001 in `year'.
     mc = iso8601_isleap(*year) ? _days_in_month_leap : _days_in_month_common;
     *month = 1;
@@ -124,23 +136,29 @@ void iso8601_to_cal(int* year, int* month, int* day, const struct iso8601_date*
 
 
 
-int iso8601_from_cal(struct iso8601_date* date, int year, int month, int day)
+void iso8601_to_ord(int* year, int* oday, const struct iso8601_date* date)
+{
+    int ndays;
+
+    // perform year calcutation
+    _to_year(year, &ndays, date);
+
+    // now we simply have number of days elapsed since day 001 in `year'.
+    *oday = ndays + 1;
+}
+
+
+
+int _from_year(struct iso8601_date* date, int year)
 {
     div_t qr;
-    const struct monthcount* mc;
 
-    // check for range / domain errors
+    // check for range errors
     if(year < -5879609 || year > 5879609) {
         errno = ERANGE;
         return -1;
     }
 
-    mc = iso8601_isleap(year) ? _days_in_month_leap : _days_in_month_common;
-    if(month < 1 || month > 12 || day < 0 || day > mc[month - 1].days) {
-        errno = EDOM;
-        return -1;
-    }
-
     // Each 400 years have 97 leap days, giving 365*400+97 = 146097 days in 400 years
     qr = div(year, 400);
     date->day = qr.quot * 146097;
@@ -156,6 +174,24 @@ int iso8601_from_cal(struct iso8601_date* date, int year, int month, int day)
     date->day += 365 * year;
     date->day += (year + 3) / 4; // there is one leap year for every four years
     date->day -= (year - 1) / 100; // but one less for every century over 0
+    return 0;
+}
+
+
+
+int iso8601_from_cal(struct iso8601_date* date, int year, int month, int day)
+{
+    const struct monthcount* mc;
+
+    // check for domain errors
+    mc = iso8601_isleap(year) ? _days_in_month_leap : _days_in_month_common;
+    if(month < 1 || month > 12 || day < 0 || day > mc[month - 1].days) {
+        errno = EDOM;
+        return -1;
+    }
+
+    // perform year calculation
+    if(_from_year(date, year)) return -1;
 
     // now get number of days elapsed up to start of month
     date->day += mc[month - 1].elapsed;

src/libiso8601/print.c

@@ -49,7 +49,13 @@ void iso8601_print(char* str, int amt, const struct iso8601_date* date,
     case iso8601_prec_day:
         iso8601_to_cal(&y, &m, &d, &dttz);
         if(y < 0) ret = snprintf(str, amt, "%05d-%02d-%02d", y, m, d);
-        ret = snprintf(str, amt, extended ? "%04d-%02d-%02d" : "%04d%02d%02d", y, m, d);
+        else ret = snprintf(str, amt, extended ? "%04d-%02d-%02d" : "%04d%02d%02d", y, m, d);
+        break;
+
+    case iso8601_prec_ord:
+        iso8601_to_ord(&y, &d, &dttz);
+        if(y < 0) ret = snprintf(str, amt, "%05d-%03d", y, d);
+        else ret = snprintf(str, amt, extended ? "%04d-%03d" : "%04d%03d", y, d);
         break;
 
     default:

src/tests/printer.c

@@ -127,6 +127,21 @@ void do_details_utc_year(struct iso8601_details* dt_out, const struct iso8601_de
     dt_out->date_prec = iso8601_prec_year;
 }
 
+void do_details_ordinal_date(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->date_prec = iso8601_prec_ord;
+    dt_out->time_prec = iso8601_prec_none;
+}
+
+void do_details_ordinal(struct iso8601_details* dt_out, const struct iso8601_details* dt_in)
+{
+    memcpy(dt_out, dt_in, sizeof(struct iso8601_details));
+    dt_out->tz_sec = 0;
+    dt_out->date_prec = iso8601_prec_ord;
+}
+
 
 
 struct test {
@@ -152,6 +167,8 @@ const struct test tests[] = {
     { "Local day", do_details_local_day },
     { "Local month", do_details_local_month },
     { "Local year", do_details_local_year },
+    { "Ordinal date", do_details_ordinal_date },
+    { "Ordinal full", do_details_ordinal },
     { 0, 0 }
 };