Author |
Topic: Sysex HEX Conversion to Decimal (Read 4993 times) |
|
abhunkin
Member
MIDI-OX Rules!
 
Posts: 35
|
 |
Sysex HEX Conversion to Decimal
« on: May 21st, 2007, 9:57pm » |
 Quote  Modify
|
I need to convert the seventh byte of an incoming 8-byte sysex string to a decimal value in order to output it in a standard MIDI message. Here's the code:
Sub Sink_SysExInput(strSysEx)
If Len(strSysEx) = 24 Then
sysex = Split(strSysex)
mox.OutputMidiMsg -1, 232, 0, sysex(6)
Exit Sub
End If
mox.SendSysExString strSysEx
End Sub
The data conversion only works when the input byte (sysex(6)) < 10dec. The values will range from 0-127dec.
How can I convert this byte correctly?
TIA -
|
|
 IP Logged |
Art Hunkins
abhunkin@uncg.edu
http://www.arthunkins.com
|
|
|
JerryJorgenrud
New Member
MIDI-OX Rules!
Posts: 0
|
|
Re: Sysex HEX Conversion to Decimal
« Reply #1 on: May 22nd, 2007, 8:12am » |
Quote Modify
|
Replace sysex(6) with cint("&H" & sysex(6))
example script - save as something.vbs
strSysEx = "F0 42 13 56 45 7A 7F F7 "
If Len(strSysEx) = 24 Then
sysex = Split(strSysex)
msgbox sysex(6)
msgbox cint("&H" & sysex(6))
End if
|
|
IP Logged |
|
|
|
abhunkin
Member
MIDI-OX Rules!
Posts: 35
|
|
Re: Sysex HEX Conversion to Decimal
« Reply #2 on: May 22nd, 2007, 11:57am » |
Quote Modify
|
Thanks, Jerry. That works perfectly.
In my case, the CInt cast seems optional, and my code runs well without it. Since I know the incoming value will be an integer between 0-127, is it safe to omit the CInt?
|
|
IP Logged |
Art Hunkins
abhunkin@uncg.edu
http://www.arthunkins.com
|
|
|
JerryJorgenrud
New Member
MIDI-OX Rules!
Posts: 0
|
|
Re: Sysex HEX Conversion to Decimal
« Reply #3 on: May 22nd, 2007, 3:03pm » |
Quote Modify
|
As you know, VBScript uses only one kind of variable, known as a variant, which can store any kind of data and thus vbscript is called a "typeless" language. But under the hood the interpreter still must cast to types by "guessing" based on context. It didn't correctly guess your intent with sysex(6) until you added the &H as a hint that you wanted that substring interpreted as a hexadecimal number. Similarly, if I don't further cast that result to an int (in my example script) then it guesses wrong again and I get a string, not a number. If the input is "7F" instead of getting 127 I get "&H7F". In the context in which you're using it (i.e. not as an input to msgbox) VBSript is apparently guessing the way you want it to and giving you a number.
So is it safe to leave out the additonal cast? Depends on the context ... and one's personal risk aversion.
I personally prefer explicit casting because bugs come from ambiguity and the more you control the less can go wrong. Or at least you can't blame someone else when they do. 
|
|
IP Logged |
|
|
|
|
User Forum ::
Powered by YaBB
Home 
Help 
Search 
Members 
Login 
Register
Reply
Notify of replies
Send Topic
Print