Arithmetic operation resulted in an overflow - Vb.Net - vb.net

Question

Hi I am getting the following error when computing GMT Time using nanoseconds as a long.
System.OverflowException: 'Arithmetic operation resulted in an overflow.'
Is there another data type that would work better with big values?
Private Sub gmtime(ByVal iSeconds As Object, ByVal iNanoseconds As Long, ByRef Timestamp As String)
Dim time As Object
Dim islpyr, lpcnt As Long
Dim t As Object
Dim i As Object
Dim ystart As Long
Dim y As Long
Dim sph As Object 'seconds per hour
Dim spd As Object 'seconds per day
Dim spy As Object 'seconds per year
Dim tm_sec As Long
Dim tm_min As Long
Dim tm_hour As Long
Dim tm_mday As Long
Dim tm_mon As Long
Dim tm_year As Long
Dim tm_wday As Long
Dim tm_yday As Long
Dim tm_isdst As Long
Dim mons(11) As Long
Dim temp As Object
Dim iMicroSeconds As Long
Dim iZeroCount As Long
Dim strZero As String
Dim strMicro As String
Dim iMicroData As Long
mons(0) = 31
mons(1) = 28
mons(2) = 31
mons(3) = 30
mons(4) = 31
mons(5) = 30
mons(6) = 31
mons(7) = 31
mons(8) = 30
mons(9) = 31
mons(10) = 30
mons(11) = 31
sph = CDec(60 * 60)
spd = CDec(24 * sph)
spy = CDec(365 * spd + 6 * sph) 'a year is about 365.25 days
tm_isdst = 0
time = CDec(iSeconds)
If time < 0 Then
time = time * (-1)
End If
i = CDec(time)
i = Fix(i / spd) Mod 7 + 4
While i >= 7
i = i - 7
End While
tm_wday = i
temp = Fix(time / spd)
temp = temp * spd
i = time - temp
tm_hour = Fix(i / sph) Mod 24
tm_min = Fix(i / 60) Mod 60
tm_sec = i Mod 60
y = Fix(time / spy)
y = y + 370
time = Fix(time / spd)
Do
islpyr = 0
If ((y Mod 4) = 0) And (((y Mod 100) <> 0) Or ((y Mod 400) = 0)) Then
islpyr = 1
End If
lpcnt = Fix(y / 4)
lpcnt = lpcnt - Fix(y / 100)
lpcnt = lpcnt + Fix(y / 400)
lpcnt = lpcnt - 89
ystart = (y - 370) * 365 + lpcnt
If ystart > time Then
y = y - 1
End If
Loop While ystart > time
time = time - ystart
If time = 365 Then
time = 0
y = y + 1
End If
If islpyr Then
time = time + 1
End If
tm_yday = time
time = time + 1
For i = 0 To 10
t = mons(i)
If (i = 1) And (islpyr = 1) Then
t = t + 1
End If
If time <= t Then
Exit For
End If
time = time - t
Next i
tm_year = y - 300 + 1900
tm_mon = i + 1
tm_mday = time
strZero = "."
iZeroCount = 6
iMicroSeconds = Fix(iNanoseconds / 1000)
iMicroData = iMicroSeconds
While iMicroSeconds <> 0
iMicroSeconds = Fix(iMicroSeconds / 10)
If (iMicroData Mod 10) = 0 Then
iMicroData = iMicroSeconds
End If
If iZeroCount <> 0 Then
iZeroCount = iZeroCount - 1
End If
End While
For i = 1 To iZeroCount
strZero = strZero + "0"
Next i
If Fix(iNanoseconds / 1000) <> 0 Then
strMicro = strZero + CStr(Fix(iNanoseconds / 1000))
Else
strMicro = strZero
End If
Timestamp = CStr(tm_year) + "-" + CStr(tm_mon) + "-" + CStr(tm_mday) + " " + CStr(tm_hour) + ":" + CStr(tm_min) + ":" + CStr(tm_sec) + strMicro
End Sub
It wouldn't let me add the code as the post is mostly code. The nanoseconds values are coming from a waveform file and this function is used to process it into GMT time.
The function is called on a loop for each line of the file and returns this error mid-way through the loop.
The value is '1.5518651852110167E+270' when it hits the error

Answer 1

I'm sorry but there's no way to put a 10^270 number inside ANY variable.
The biggest variable for numbers is Long that holds:
signed 64-bit (8-byte) integers ranging in value from
-9,223,372,036,854,775,808 through 9,223,372,036,854,775,807
(9.2...E+18).
From Long DataType
I sueggest you to avoiding counting time in nanoseconds instead use seconds, minutes, or even days if your TimeSpan is too big.
Counting time in nanoseconds is pointless.
Remarks
If you couldn't avoid using nanoseconds because your file is in nanoseconds your only option is to convert you nanoseconds value in a DateTime format on every line and hope that the value will be shorter than 9.2E+18
Otherwise you could use a BigInteger and use it to calculate a DateTime for every line of your file.
Just for the curiosity: You would need a 896 bytes unsigned DataType to store a 1.5*10^270 inside it.