' Simple Array Functions
' by Joseph Essin
' Feel free to use in your own code. No need to credit me.
'
' For use with LBB:
' http://www.bbcbasic.co.uk/lbb/
'
' The functionality to make this work is not found in
' Liberty BASIC alone. This is for use with Richard Russell's
' Liberty BASIC Booster "compiler."
'
' Please find LBB below:
'
' http://www.bbcbasic.co.uk/lbb/
' -------------------------------------------------------------- '

' These are necessary for the Array Library.
' Don't name any of your arrays these names
' or you'll be subject to data loss.
Redim ArrayLib(0)
' -------------------------------------------------------------- '


Redim things(5) ' Make it hold five things

For i = 1 To 5
	things(i) = 5^i
	Print i, things(i)
Next i

Print "UBound before redim preserve: "; UBound(things())

Call RedimPreserve things(), 10

Print "UBound after redim preserve: "; UBound(things())

End


Function UBound(array())
    ' Returns the upper index limit of array().
    ' ---------------------------------------------------------- '
    ' Special thanks to Richard for the implementation of the
    ' binary chop method.
    ' ---------------------------------------------------------- '
    s = 2^24
    do
        On Error Goto [Error]
        [Error]
        s = int(s / 2)
        temp = array(UBound + s)
        UBound = UBound + s
    loop until s = 0
End Function



Sub RedimPreserve array(), newSize
	' Redimensions the given one-dimensional array() to the
	' specified newSize.
    ' ---------------------------------------------------------- '
	' Array indexes begin at 0, so keep that in mind when
	' specifying newSize.
	' ---------------------------------------------------------- '
	u = UBound(array()) ' Get the upper limit
	Redim ArrayLib(u)
	For i = 0 To u
        ArrayLib(i) = array(i) ' Get old contents
	Next i
	Redim array(newSize) ' Resize given array.
	For i = 0 To u
        array(i) = ArrayLib(i) ' Replace old contents that were lost.
	Next i
End Sub 

ReDim Preserve array(newSize)