Convert VB Double to Pascal Real

[David Scemama]

Hi,

I'm writing a program using VB.NET that needs to communicate with a DOS
Pascal program than cannot be modified. The communication channel is through
some file databases, and I have a huge problem writing VB Double values to
the file so as the Pascal program can read them as Pascal Real values.

I've managed to find the algorithm to read the Pascal Real format and
convert it to a VB Double, but I cannot figure out the opposite algorithm.

Can someone help me reverse my algorithm and develop the function
"DoubleToRe al (ByVal Data As Double) As String"

Here is the conversion from real to double:

Public Function RealToDouble(By Val Data As String) As Double
Dim dMantissa As Double
Dim i As Integer
Dim j As Long
Dim k As Long

If Len(Data) <> 6 Then
'Err.Raise
'exception
Exit Function
End If

'accumulate the mantissa
dMantissa = 1
For i = 6 To 2 Step -1
For j = CType(IIf(i = 6, 6, 7), Long) To 0 Step -1
k = k + 1
If (Asc(Mid$(Data, i, 1)) And CType(2 ^ j, Long)) <> 0 Then
dMantissa = dMantissa + 2 ^ -k
End If
Next j
Next i

'finally, assemble all the pieces into a number
If (Asc(Mid$(Data, 6, 1)) And &H80) = &H80 Then
RealToDouble = -dMantissa * 2 ^ (Asc(Mid$(Data, 1, 1)) - 129)
Else
RealToDouble = dMantissa * 2 ^ (Asc(Mid$(Data, 1, 1)) - 129)
End If

Try
Return ([Decimal].Round(CDec(Rea lToDouble), 2))
Catch ex As Exception
'MsgBox("RealTo Double, Conversion error: " & Data & "; " &
RealToDouble.To String, MsgBoxStyle.Cri tical)
Return 0
End Try

End Function

Thanks for your help
David

[One Handed Man]

I probably have not understood you correctly, but can you not simply convert
the double to a string an then truncate the string to the correct length?

As far as I am aware, a real number is simply a number which is not
imaginary, so I dont know how this differs in a Pascal Real number. Your
function seems to convert a string into a double but goes a long way around.
BTW, I actually tried to convert "1.2345" and it returned 0.0

I'm sure Im missing something here, can you illuminate ?

Regards - OHM

David Scemama wrote:

Hi,

I'm writing a program using VB.NET that needs to communicate with a
DOS Pascal program than cannot be modified. The communication channel
is through some file databases, and I have a huge problem writing VB
Double values to the file so as the Pascal program can read them as
Pascal Real values.

I've managed to find the algorithm to read the Pascal Real format and
convert it to a VB Double, but I cannot figure out the opposite
algorithm.

Can someone help me reverse my algorithm and develop the function
"DoubleToRe al (ByVal Data As Double) As String"

Here is the conversion from real to double:

Public Function RealToDouble(By Val Data As String) As Double
Dim dMantissa As Double
Dim i As Integer
Dim j As Long
Dim k As Long

If Len(Data) <> 6 Then
'Err.Raise
'exception
Exit Function
End If

'accumulate the mantissa
dMantissa = 1
For i = 6 To 2 Step -1
For j = CType(IIf(i = 6, 6, 7), Long) To 0 Step -1
k = k + 1
If (Asc(Mid$(Data, i, 1)) And CType(2 ^ j, Long)) <>
0 Then dMantissa = dMantissa + 2 ^ -k
End If
Next j
Next i

'finally, assemble all the pieces into a number
If (Asc(Mid$(Data, 6, 1)) And &H80) = &H80 Then
RealToDouble = -dMantissa * 2 ^ (Asc(Mid$(Data, 1, 1)) -
129) Else
RealToDouble = dMantissa * 2 ^ (Asc(Mid$(Data, 1, 1)) -
129) End If

Try
Return ([Decimal].Round(CDec(Rea lToDouble), 2))
Catch ex As Exception
'MsgBox("RealTo Double, Conversion error: " & Data & "; " &
RealToDouble.To String, MsgBoxStyle.Cri tical)
Return 0
End Try

End Function

Thanks for your help
David

[Cor]

Hi OHM

Can you take a look at that answer from cc I have sended in and give some
comments.

All is there just paste it on a new form and run.

Or I don't understand it (and no user will understand it) or it is a real
big bug.

Cor

[One Handed Man]

I think my reader must be out of sync here. I dont see this reply. I have
noticed this with quite a few posts lately. Can you repost under this one
please.

Thanks - OHM

Cor wrote:

Hi OHM

Can you take a look at that answer from cc I have sended in and give
some comments.

All is there just paste it on a new form and run.

Or I don't understand it (and no user will understand it) or it is a
real big bug.

Cor

[Cor]

Hi OHM this was a question from cc

how do I make keyboard & mouse temporary not response to desktop

I did want to answer with simple" me.enabled = false", but did not trust it
because this answer seems to simple to me. So I did test it, and I find
this strange and do not understand it.

Who will test it also and tell me if this is normal behaviour or a bug?
The problem is that when you pusth the button when enabled is false, it
keeps responding to the events, so you have to push several times on the not
locked button.

Framework 1.1

Cor

\\\
' needs one button and one label on a form
Private Sub Button1_Click(B yVal sender As System.Object, _
ByVal e As System.EventArg s) Handles Button1.Click
Static i As Integer
Me.Button1.Text = "locked"
Dim ctr As Control
' Me.Enabled = false did not work so
'I did try this but does not work either
For Each ctr In Me.Controls
ctr.Enabled = False
Next
Me.Refresh()
Dim y As Integer
For y = 1 To 20
Threading.Threa d.Sleep(50)
i = i + 50
Me.Label1.Text = i.ToString
Me.Refresh()
Next
For Each ctr In Me.Controls
ctr.Enabled = True
Next
Me.Button1.Text = "Unlocked"
End Sub
///

[One Handed Man]

But this post is about Mouse and keyboard, the current thread we are in is
regarding Double/Pascal Real number conversions?

Whats happening, am I going mad ?

Regards OHM
Cor wrote:

Hi OHM this was a question from cc

how do I make keyboard & mouse temporary not response to desktop

I did want to answer with simple" me.enabled = false", but did not
trust it because this answer seems to simple to me. So I did test
it, and I find this strange and do not understand it.

Who will test it also and tell me if this is normal behaviour or a
bug?
The problem is that when you pusth the button when enabled is false,
it keeps responding to the events, so you have to push several times
on the not locked button.

Framework 1.1

Cor

\\\
' needs one button and one label on a form
Private Sub Button1_Click(B yVal sender As System.Object, _
ByVal e As System.EventArg s) Handles Button1.Click
Static i As Integer
Me.Button1.Text = "locked"
Dim ctr As Control
' Me.Enabled = false did not work so
'I did try this but does not work either
For Each ctr In Me.Controls
ctr.Enabled = False
Next
Me.Refresh()
Dim y As Integer
For y = 1 To 20
Threading.Threa d.Sleep(50)
i = i + 50
Me.Label1.Text = i.ToString
Me.Refresh()
Next
For Each ctr In Me.Controls
ctr.Enabled = True
Next
Me.Button1.Text = "Unlocked"
End Sub
///

[Cor]

Hi OHM

No I asket you to look to a posible Bug I had posted.

I was curious if I became crazy or it was a bug.

Cor

[David Scemama]

The Pascal Real type, is stored on 6 bytes with a very special coding. When
you write a real value in a file, 6 bytes are written to represent the value
(obviously, no language writes the string representation of the real !). My
function reads the 6 bytes and convert them to a VB double.

I need the reverse function !

David
"One Handed Man" <Bo****@Duck.ne t> wrote in message
news:bp******** **@titan.btinte rnet.com...

I probably have not understood you correctly, but can you not simply convert the double to a string an then truncate the string to the correct length?

As far as I am aware, a real number is simply a number which is not
imaginary, so I dont know how this differs in a Pascal Real number. Your
function seems to convert a string into a double but goes a long way around. BTW, I actually tried to convert "1.2345" and it returned 0.0

I'm sure Im missing something here, can you illuminate ?

Regards - OHM

David Scemama wrote:

Hi,

I'm writing a program using VB.NET that needs to communicate with a
DOS Pascal program than cannot be modified. The communication channel
is through some file databases, and I have a huge problem writing VB
Double values to the file so as the Pascal program can read them as
Pascal Real values.

I've managed to find the algorithm to read the Pascal Real format and
convert it to a VB Double, but I cannot figure out the opposite
algorithm.

Can someone help me reverse my algorithm and develop the function
"DoubleToRe al (ByVal Data As Double) As String"

Here is the conversion from real to double:

Public Function RealToDouble(By Val Data As String) As Double
Dim dMantissa As Double
Dim i As Integer
Dim j As Long
Dim k As Long

If Len(Data) <> 6 Then
'Err.Raise
'exception
Exit Function
End If

'accumulate the mantissa
dMantissa = 1
For i = 6 To 2 Step -1
For j = CType(IIf(i = 6, 6, 7), Long) To 0 Step -1
k = k + 1
If (Asc(Mid$(Data, i, 1)) And CType(2 ^ j, Long)) <>
0 Then dMantissa = dMantissa + 2 ^ -k
End If
Next j
Next i

'finally, assemble all the pieces into a number
If (Asc(Mid$(Data, 6, 1)) And &H80) = &H80 Then
RealToDouble = -dMantissa * 2 ^ (Asc(Mid$(Data, 1, 1)) -
129) Else
RealToDouble = dMantissa * 2 ^ (Asc(Mid$(Data, 1, 1)) -
129) End If

Try
Return ([Decimal].Round(CDec(Rea lToDouble), 2))
Catch ex As Exception
'MsgBox("RealTo Double, Conversion error: " & Data & "; " &
RealToDouble.To String, MsgBoxStyle.Cri tical)
Return 0
End Try

End Function

Thanks for your help
David

[One Handed Man]

This may be because the message goes out in the message queue, the button
does not respond to it until the loop finishes, then it processes the click
( I think ).

Regards - OHM
Cor wrote:

Hi OHM this was a question from cc

how do I make keyboard & mouse temporary not response to desktop

I did want to answer with simple" me.enabled = false", but did not
trust it because this answer seems to simple to me. So I did test
it, and I find this strange and do not understand it.

Who will test it also and tell me if this is normal behaviour or a
bug?
The problem is that when you pusth the button when enabled is false,
it keeps responding to the events, so you have to push several times
on the not locked button.

Framework 1.1

Cor

\\\
' needs one button and one label on a form
Private Sub Button1_Click(B yVal sender As System.Object, _
ByVal e As System.EventArg s) Handles Button1.Click
Static i As Integer
Me.Button1.Text = "locked"
Dim ctr As Control
' Me.Enabled = false did not work so
'I did try this but does not work either
For Each ctr In Me.Controls
ctr.Enabled = False
Next
Me.Refresh()
Dim y As Integer
For y = 1 To 20
Threading.Threa d.Sleep(50)
i = i + 50
Me.Label1.Text = i.ToString
Me.Refresh()
Next
For Each ctr In Me.Controls
ctr.Enabled = True
Next
Me.Button1.Text = "Unlocked"
End Sub
///

[Cor]

But should it do that?