asked on

Convert Unicode String to ASCII String

I have a simple problem that i need a simple answer for. I have a string that is in unicode format that I want to convert to ASCII format. If the character is not in the ASCII range, then it just needs to be dropped. I need this function in ASP (VBScript), so I can't use any fancy C++ function. For example, I have the following code:

-----------------------------------------------------
Dim sUnicodeValue, sAsciiValue
sUnicodeValue = "Ÿ"
sAsciiValue = ConvertUnicodeStringToAscii(sUnicodeValue) ' This function is what I need
Response.Write "Unicode = " & sUnicodeValue & " "
Response.Write "ASCII = " & sAsciiValue & " "
-----------------------------------------------------

How can I get the above to work? Any help is appreciated...

sudhakar_koundinya

Hope this will help you

Function UnicodeToAscii(ByRef pstrUnicode)
      Dim llngLength
      Dim llngIndex
      Dim llngAscii
      Dim lstrAscii

      llngLength = Len(pstrUnicode)

      For llngIndex = 1 To llngLength
            llngAscii = Asc(Mid(pstrUnicode, llngIndex, 1))
            lstrAscii = lstrUnicode & ChrB(llngAscii)
      Next

      UnicodeToAscii = lstrAscii
End Function

Regards
Sudhakar

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sudhakar_koundinya

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sudhakar_koundinya

Here is your final code

<%
Function UnicodeToAscii(ByRef pstrUnicode)
Dim llngLength
Dim llngIndex
Dim llngAscii
Dim lstrAscii

llngLength = Len(pstrUnicode)

For llngIndex = 1 To llngLength
llngAscii = Asc(Mid(pstrUnicode, llngIndex, 1))
lstrAscii = lstrUnicode & ChrB(llngAscii)
Next

UnicodeToAscii = lstrAscii
End Function

Function AsciiToUnicode(ByRef pstrAscii)

Dim llngLength
Dim llngIndex
Dim llngAscii
Dim lstrUnicode

llngLength = LenB(pstrAscii)

For llngIndex = 1 To llngLength
llngAscii = AscB(MidB(pstrAscii, llngIndex, 1))
lstrUnicode = lstrUnicode & Chr(llngAscii)
Next

AsciiToUnicode = lstrUnicode

End Function

Dim sUnicodeValue, sAsciiValue
sUnicodeValue = "Ÿ"
sAsciiValue = UnicodeToAscii(sUnicodeValue) ' This function is what I need
Response.Write "Unicode = " & sUnicodeValue & " "
Response.Write "ASCII = " & sAsciiValue & " "
Response.Write " Unicode = " & AsciiToUnicode(sAsciiValue) & " "
%>

rlibrandi

StrConv("Ÿ", vbFromUnicode) - to convert from Unicode to system default codepage

StrConv("ascii", vbUnicode) - converts to Unicode

sudhakar_koundinya

This is more asy for u

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/vbenlr98/html/vafctstrconvx.asp

sudhakar_koundinya

*asy=Easy

Oops,
I haven't refreshed. You are quite fast

bmccleary

ASKER

Thanks guys, but I have two problems...

First, StrConv is not available as a function in VBScript so I can't use it in my ASP pages

Secondly, Sudhaker, I modified you code slightly so that I only get the standard (not even extended) ASCII character set, as follows:

Function ConvertToASCII(sValue)
Dim i, rv, charValue
rv = ""
For i = 1 To Len(sValue)
charValue = Asc(Mid(sValue, i, 1))
If charValue <= 127 Then
rv = rv & Chr(charValue)
End If
Next
ConvertToStandardASCII = rv
End Function

THe problem is that some of my strings are very long (1MB+), and using this function causes severe processor loading and memory utilization (because of the continual appending of the string). I know that I can use a complex VB string builder method, but I was hoping for a simpler method.

Do either of you know a simpler method to make my function work, or how to get StrConv to work with VBScript?

sudhakar_koundinya

I assume that more or less both will have same speed performance. Maybe strconv is a bit faster than user defined function.

Coming to the strconv in asp pages, I think it is there with VBScript engine. Although I am not able to test the function at my side because of Type Mismatch error, I strongly say it is there. May be some body can help u on this

Regards
Sudhakar

Anthony Perkins

Since the StrConv is not available in VBScript, consider writing a VB dll with this function that you use from ASP. Assuming it is fast enough, that is.

sudhakar_koundinya

>> Since the StrConv is not available in VBScript, consider writing a VB dll with this function that you use from ASP. Assuming it is fast enough, that is.

I thought the same. But as this is web based project, the hosting people may not accept such components, I think.

bmccleary

ASKER

Thanks to you all for your inputs. I was hoping for either something cleaner or quicker, but I guess this is one example of why classic ASP is going the way of the dodo! Thanks again.

dekeldate

I bumped into this (by way of google) while investigating how to make fast strings, so I will put in a way that should help the speed of the processing, even though it is closed, feeling generous.

I am more familiar with VB Classic so I hope this works for you without any changes

Function ConvertToASCII(sValue)
Dim i, lStringLength, sReturnValue, iBufferSize, lCurStringSize, charValue

lStringSize= len(svalue)
iBufferSize = 15000
lCurStringSize = 0

For i = 1 To lStringLength
If i > iCurStringSize Then
iCurStringSize = iCurStringSize + iBufferSize
sReturnValue = sReturnValue & String$(iBufferSize, 0)
End if
charValue = AscB$(MidB$(sValue, i)) ' notice I am not specifiying the length, this makes it
' faster and only the first charcter is taken anyway

Mid$(sReturnValue, lCurStringSize + 1, 1) = Chr$(charValue)
Next

End Function

Aker

Sudhakar you are a SUPERSTAR! THANK YOU THANK YOU