change.c File Reference

#include <grass/datetime.h>

Include dependency graph for change.c:

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Functions
int	datetime_change_from_to (DateTime *dt, int from, int to, int round)
	Changes the from/to of the type for dt. The 'from/to' must be legal values for the mode of dt; (if they are not legal, then the original values are preserved, dt is not changed). Returns: 0 OK -1 invalid 'dt' -2 invalid 'from/to'

Function Documentation

datetime_change_from_to()

int datetime_change_from_to	(	DateTime *	dt,
		int	from,
		int	to,
		int	round )

Changes the from/to of the type for dt. The 'from/to' must be legal values for the mode of dt; (if they are not legal, then the original values are preserved, dt is not changed). Returns: 0 OK -1 invalid 'dt' -2 invalid 'from/to'

• round = negative implies floor() [decrease magnitude] 0 implies normal rounding, [incr/decr magnitude] positive implies ceil() [increase magnitude]
• If dt.from < 'from' (losing "lower" elements), convert the "lost" values to the equivalent value for the new 'from' Lost elements are then set to zero. (This case can only occur for dt.mode relative): months += lost years * 12 ; years = 0 hours += lost days * 24 ; days = 0 minutes += lost hours * 60 ; hours = 0 seconds += lost minutes * 60.0 ; minutes = 0
• If dt.from > 'from' (adding "lower" elements), the new elements are set to zero.
• If dt.to < 'to' (adding "higher" elements), the new elements are set to zero.
• If dt.to > 'to' (losing "higher" elements), the the new 'to' is adjusted according to the value for 'round' After rounding the "lost" elements are set to zero.

Parameters

dt
from
to
round

Returns

int

Definition at line 54 of file change.c.

References datetime_days_in_year(), datetime_increment(), datetime_is_absolute(), datetime_is_valid_type(), datetime_set_type(), and x.

Referenced by datetime_difference(), datetime_get_local_timezone(), and datetime_increment().