//! Returns a negative duration_type
duration_type get_neg_offset(const date_type& d) const
{
ymd_type ymd(d.year_month_day());
if (origDayOfMonth_ == 0) {
origDayOfMonth_ = ymd.day;
day_type endOfMonthDay(cal_type::end_of_month_day(ymd.year,ymd.month));
if (endOfMonthDay == ymd.day) {
origDayOfMonth_ = -1; //force the value to the end of month
}
}
typedef date_time::wrapping_int2<short,1,12> wrap_int2;
typedef typename wrap_int2::int_type int_type;
wrap_int2 wi(ymd.month);
//calc the year wrap around, add() returns 0 or 1 if wrapped
int_type year = wi.subtract(static_cast<int_type>(f_));
year = static_cast<int_type>(year + ymd.year); //calculate resulting year
//find the last day for the new month
day_type resultingEndOfMonthDay(cal_type::end_of_month_day(year, wi.as_int()));
//original was the end of month -- force to last day of month
if (origDayOfMonth_ == -1) {
return date_type(year, wi.as_int(), resultingEndOfMonthDay) - d;
}
day_type dayOfMonth = origDayOfMonth_;
if (dayOfMonth > resultingEndOfMonthDay) {
dayOfMonth = resultingEndOfMonthDay;
}
return date_type(year, wi.as_int(), dayOfMonth) - d;
}
//! Put date into an ostream
static void date_put(const date_type& d,
ostream_type& os,
const facet_type& f)
{
special_values sv = d.as_special();
if (sv == not_special) {
ymd_type ymd = d.year_month_day();
ostream_ymd_formatter<ymd_type, facet_type, charT>::ymd_put(ymd, os, f);
}
else { // output a special value
std::ostreambuf_iterator<charT> coi(os);
f.put_special_value(coi, sv);
}
}
//! Convert to a date to standard string using format policies
static std::string date_to_string(date_type d)
{
typedef typename date_type::ymd_type ymd_type;
if (d.is_not_a_date()) {
return format_type::not_a_date();
}
if (d.is_neg_infinity()) {
return format_type::neg_infinity();
}
if (d.is_pos_infinity()) {
return format_type::pos_infinity();
}
ymd_type ymd = d.year_month_day();
return ymd_formatter<ymd_type, format_type>::ymd_to_string(ymd);
}
