VB:GetTimePeriod

gistfile1.vb

''' <summary>
''' Simple parser for time periods from a string.
''' e.g.
'''   1d
'''   1m
'''   2days
''' </summary>
''' <param name="str"></param>
''' <returns></returns>
''' <remarks></remarks>
Public Shared Function GetTimePeriod(str As String) As TimeSpan

	If str Is Nothing Then
		Throw New ArgumentNullException("str")
	End If

	'Plain old regex: (\d+)([A-Za-z]+)?
	Dim re As Regex = New Regex("(?<Value>\d+)(?<Unit>[A-Za-z]+)?", RegexOptions.IgnoreCase)
	Dim m = re.Match(str)

	If (m.Success) Then

		Dim unit = m.Groups("Unit").Value.ToLower()
		Dim value = Integer.Parse(m.Groups("Value").Value)

		Select Case unit
			Case "d", "day", "days"
				Return New TimeSpan(value, 0, 0, 0)
			Case "h", "hour", "hours"
				Return New TimeSpan(0, value, 0, 0)
			Case "m", "minute", "minutes"
				Return New TimeSpan(0, 0, value, 0)
			Case Else
				' assume hours
				Return New TimeSpan(0, value, 0, 0)
		End Select

	End If

	Return TimeSpan.Zero

End Function