/// <summary>
/// This method returns the end of the month that contains the given date. The method has not
/// been designed to work if the dayShift is outside the range -30 to +30.
/// </summary>
/// <param name="date">the date whose month end is to be returned</param>
/// <param name="dayShift">The shift (measured in days) in the definition of monthly time steps.
/// If the value is 0, then months are defined as ending on the last day of the standard calendar
/// month. If the value is 1, then months are defined as ending on the 1st day of the standard
/// calendar month. If the value is -1, then months are defined as ending on the day before the
/// last day of the standard calendar month.</param>
public static DateTime RoundMonthEnd(this DateTime date, int dayShift)
{
DateTime endDate = new DateTime(date.Year, date.Month, 1).AddMinutes(-1).AddDays(dayShift);
while (endDate < date)
{
endDate = endDate.AddMonthsByEnd(dayShift, 1);
}
return(endDate);
}
/// <summary>
/// This method computes the end date when given the start date, a regular time step size,
/// and the number of time steps that should be added to the start date.
/// </summary>
/// <param name="startDate">The start date for the calculation</param>
/// <param name="unit">Code for the time step units (e.g. hour, day, month...)</param>
/// <param name="stepSize">The number of units per time step (e.g. Size=10 for 10-day time steps)</param>
/// <param name="numSteps">The number of time steps to add to the start date</param>
/// <returns>The end date of the calculation</returns>
public static DateTime IncrementDate(DateTime startDate, TimeStepUnitCode unit,
short stepSize, int numSteps)
{
DateTime calcDate; // The end date of the calculation
DateTime date = startDate;
// The DateTime class's various 'Add' methods lend themselves to
// a switch statement so that whichever units the time step is measured in,
// we can call the corresponding 'Add' method.
switch (unit)
{
case TimeStepUnitCode.Minute:
calcDate = date.AddMinutes(stepSize * numSteps);
break;
case TimeStepUnitCode.Hour:
calcDate = date.AddHours(stepSize * numSteps);
break;
case TimeStepUnitCode.Day:
calcDate = date.AddDays(stepSize * numSteps);
break;
case TimeStepUnitCode.Week:
calcDate = date.AddDays(stepSize * numSteps * 7);
break;
case TimeStepUnitCode.Month:
// For now, we only handle monthly time steps that end on regular calendar month
// See https://github.com/hydrologics/Oasis/issues/163
date = date.RoundMonthEnd(0);
calcDate = date.AddMonthsByEnd(0, stepSize * numSteps);
break;
case TimeStepUnitCode.Year:
// For now, we only handle yearly time steps that end on regular calendar year
// See https://github.com/hydrologics/Oasis/issues/163
date = new DateTime(date.Year + 1, 1, 1).AddMinutes(-1);
calcDate = date.AddYears(stepSize * numSteps);
break;
default:
calcDate = date;
break;
}
return(calcDate);
}
/// <summary>
/// This method determines how many regular time steps are contained between the given
/// start date and end date, when given a regular time step size.
/// The method does not care whether the input start date comes before the input end
/// date. It simply returns the absolute value of the number of steps between the given dates.
/// Please note that the returned value is not inclusive of the first time step. That is, if the
/// start date is 1/1 and the end date is 1/1, then the number of days between the given dates
/// is returned as zero.
/// </summary>
/// <param name="startDate">The date when the count begins</param>
/// <param name="endDate">The date when the count ends</param>
/// <param name="unit">Code for the time step units (e.g. hour, day, month...)</param>
/// <param name="stepSize">The number of units per time step (e.g. Size=10 for 10-day time steps)</param>
/// <returns></returns>
public static int CountSteps(DateTime startDate, DateTime endDate,
TimeStepUnitCode unit, short stepSize)
{
DateTime calcDate; // Date value that will be iterated for the counting process
int i = 0; // Counter for how many time steps
// Method does not care whether the input start date comes before the input end
// date. It simply returns the absolute value of the number of steps between the given dates.
if (endDate < startDate)
{
calcDate = endDate;
endDate = startDate;
startDate = calcDate;
}
calcDate = startDate;
// The DateTime class's various 'Add' methods lend themselves to
// a switch statement so that whichever units the time step is measured in,
// we can call the corresponding 'Add' method. The counting loop inside of
// the switch statement is deliberately selected to be faster than a switch
// statement inside of a loop.
switch (unit)
{
case TimeStepUnitCode.Minute:
for (i = 0; calcDate < endDate; i++)
{
calcDate = calcDate.AddMinutes(stepSize);
}
break;
case TimeStepUnitCode.Hour:
for (i = 0; calcDate < endDate; i++)
{
calcDate = calcDate.AddHours(stepSize);
}
break;
case TimeStepUnitCode.Day:
for (i = 0; calcDate < endDate; i++)
{
calcDate = calcDate.AddDays(stepSize);
}
break;
case TimeStepUnitCode.Week:
for (i = 0; calcDate < endDate; i++)
{
calcDate = calcDate.AddDays(stepSize * 7);
}
break;
case TimeStepUnitCode.Month:
// For now, we only handle monthly time steps that end on regular calendar month
// See https://github.com/hydrologics/Oasis/issues/163
calcDate = RoundMonthEnd(calcDate, 0);
for (i = 0; calcDate < endDate; i++)
{
calcDate = calcDate.AddMonthsByEnd(0, stepSize);
}
break;
case TimeStepUnitCode.Year:
// For now, we only handle yearly time steps that end on regular calendar year
// See https://github.com/hydrologics/Oasis/issues/163
calcDate = new DateTime(calcDate.Year + 1, 1, 1).AddMinutes(-1);
for (i = 0; calcDate < endDate; i++)
{
calcDate = calcDate.AddYears(stepSize);
}
break;
}
return(i);
}
public void AddMonthsByEnd_30c()
{
DateTime d = new DateTime(1959, 3, 30);
Assert.AreEqual(d, d.AddMonthsByEnd(30, 0));
Assert.AreEqual(new DateTime(1959, 4, 30), d.AddMonthsByEnd(30, 1));
Assert.AreEqual(new DateTime(1959, 5, 30), d.AddMonthsByEnd(30, 2));
Assert.AreEqual(new DateTime(1960, 3, 1), d.AddMonthsByEnd(30, 11));
Assert.AreEqual(new DateTime(1960, 3, 30), d.AddMonthsByEnd(30, 12));
Assert.AreEqual(new DateTime(1960, 4, 30), d.AddMonthsByEnd(30, 13));
Assert.AreEqual(new DateTime(1960, 5, 30), d.AddMonthsByEnd(30, 14));
Assert.AreEqual(new DateTime(1960, 6, 30), d.AddMonthsByEnd(30, 15));
Assert.AreEqual(new DateTime(1959, 3, 2), d.AddMonthsByEnd(30, -1));
Assert.AreEqual(new DateTime(1959, 1, 30), d.AddMonthsByEnd(30, -2));
Assert.AreEqual(new DateTime(1958, 4, 30), d.AddMonthsByEnd(30, -11));
Assert.AreEqual(new DateTime(1958, 3, 30), d.AddMonthsByEnd(30, -12));
Assert.AreEqual(new DateTime(1958, 3, 2), d.AddMonthsByEnd(30, -13));
}
public void AddMonthsByEnd_2c()
{
DateTime d = new DateTime(1959, 3, 2);
Assert.AreEqual(d, d.AddMonthsByEnd(2, 0));
Assert.AreEqual(new DateTime(1959, 4, 2), d.AddMonthsByEnd(2, 1));
Assert.AreEqual(new DateTime(1959, 5, 2), d.AddMonthsByEnd(2, 2));
Assert.AreEqual(new DateTime(1960, 3, 2), d.AddMonthsByEnd(2, 12));
Assert.AreEqual(new DateTime(1960, 4, 2), d.AddMonthsByEnd(2, 13));
Assert.AreEqual(new DateTime(1960, 5, 2), d.AddMonthsByEnd(2, 14));
Assert.AreEqual(new DateTime(1960, 6, 2), d.AddMonthsByEnd(2, 15));
Assert.AreEqual(new DateTime(1959, 2, 2), d.AddMonthsByEnd(2, -1));
Assert.AreEqual(new DateTime(1959, 1, 2), d.AddMonthsByEnd(2, -2));
Assert.AreEqual(new DateTime(1958, 4, 2), d.AddMonthsByEnd(2, -11));
Assert.AreEqual(new DateTime(1958, 3, 2), d.AddMonthsByEnd(2, -12));
Assert.AreEqual(new DateTime(1958, 2, 2), d.AddMonthsByEnd(2, -13));
}
public void AddMonthsByEnd_1b()
{
DateTime d = new DateTime(1960, 3, 1);
Assert.AreEqual(d, d.AddMonthsByEnd(1, 0));
Assert.AreEqual(new DateTime(1960, 4, 1), d.AddMonthsByEnd(1, 1));
Assert.AreEqual(new DateTime(1960, 5, 1), d.AddMonthsByEnd(1, 2));
Assert.AreEqual(new DateTime(1961, 3, 1), d.AddMonthsByEnd(1, 12));
Assert.AreEqual(new DateTime(1961, 4, 1), d.AddMonthsByEnd(1, 13));
Assert.AreEqual(new DateTime(1961, 5, 1), d.AddMonthsByEnd(1, 14));
Assert.AreEqual(new DateTime(1961, 6, 1), d.AddMonthsByEnd(1, 15));
Assert.AreEqual(new DateTime(1960, 2, 1), d.AddMonthsByEnd(1, -1));
Assert.AreEqual(new DateTime(1960, 1, 1), d.AddMonthsByEnd(1, -2));
Assert.AreEqual(new DateTime(1959, 4, 1), d.AddMonthsByEnd(1, -11));
Assert.AreEqual(new DateTime(1959, 3, 1), d.AddMonthsByEnd(1, -12));
Assert.AreEqual(new DateTime(1959, 2, 1), d.AddMonthsByEnd(1, -13));
}
public void AddMonthsByEnd_0c()
{
DateTime d = new DateTime(1959, 2, 28);
Assert.AreEqual(d, d.AddMonthsByEnd(0, 0));
Assert.AreEqual(new DateTime(1959, 3, 31), d.AddMonthsByEnd(0, 1));
Assert.AreEqual(new DateTime(1959, 4, 30), d.AddMonthsByEnd(0, 2));
Assert.AreEqual(new DateTime(1960, 2, 29), d.AddMonthsByEnd(0, 12));
Assert.AreEqual(new DateTime(1960, 3, 31), d.AddMonthsByEnd(0, 13));
Assert.AreEqual(new DateTime(1960, 4, 30), d.AddMonthsByEnd(0, 14));
Assert.AreEqual(new DateTime(1960, 5, 31), d.AddMonthsByEnd(0, 15));
Assert.AreEqual(new DateTime(1959, 1, 31), d.AddMonthsByEnd(0, -1));
Assert.AreEqual(new DateTime(1958, 12, 31), d.AddMonthsByEnd(0, -2));
Assert.AreEqual(new DateTime(1958, 3, 31), d.AddMonthsByEnd(0, -11));
Assert.AreEqual(new DateTime(1958, 2, 28), d.AddMonthsByEnd(0, -12));
Assert.AreEqual(new DateTime(1958, 1, 31), d.AddMonthsByEnd(0, -13));
}
