CNV_UTF8FromLatin1

CryptoSys PKI Toolkit Manual

CNV_UTF8FromLatin1

CNV_UTF8FromLatin1 converts a string of 8-bit Latin-1 characters into UTF-8 format.

VB6/VBA Syntax


Public Declare Function CNV_UTF8FromLatin1 Lib "diCrPKI.dll" 
    (ByVal strOutput As String, ByVal nOutChars As Long, ByVal strInput As String) As Long

nLen = CNV_UTF8FromLatin1(strOutput, nOutChars, strInput)

Parameters

strOutput: [out] String to receive the output.
nOutChars: [in] Long specifying the maximum number of characters to be received.
strInput: [in] String of Latin-1 characters to be decoded.

C/C++ Syntax


long _stdcall CNV_UTF8FromLatin1(char *szOutput, long nOutChars, const char *szInput);

Returns (VB6/C)

Long: If successful, the return value is a positive number indicating the number of (single-byte) characters in the output string, or number of characters required if nOutChars is zero; otherwise it returns a negative error code.

.NET Equivalent

Use the in-built method System.Text.Encoding.

Remarks

Will set up to nOutChars characters in the output string. If nOutChars is zero, it returns the required number of (single-byte) characters.

Example

Dim strData As String
Dim strDataUTF8 As String
Dim strDataLatin1 As String
Dim nRet As Long
Dim nLen As Long

' Our original string data is in "Latin-1" encoding
strData = "Asociación Mexicana de Estándares para el Comercio Electrónico A.C.|México|"
Debug.Print strData

' So convert to UTF-8
nLen = CNV_UTF8FromLatin1("", 0, strData)
If nLen < 0 Then
    Debug.Print "Failed to convert to UTF-8: " & nLen
    Exit Function
End If
strDataUTF8 = String(nLen, " ")
nLen = CNV_UTF8FromLatin1(strDataUTF8, nLen, strData)
' Which may not display correctly in VB6...!
Debug.Print strDataUTF8

' Now convert back to Latin-1
nLen = CNV_Latin1FromUTF8("", 0, strDataUTF8)
strDataLatin1 = String(nLen, " ")
nLen = CNV_Latin1FromUTF8(strDataLatin1, nLen, strDataUTF8)
Debug.Print strDataLatin1

This should give results like this:

Asociación Mexicana de Estándares para el Comercio Electrónico A.C.|México|
AsociaciÃ³n Mexicana de EstÃ¡ndares para el Comercio ElectrÃ³nico A.C.|MÃ©xico|
Asociación Mexicana de Estándares para el Comercio Electrónico A.C.|México|

Note how the second string includes the UTF-8 double-byte characters like "Ã³" instead of the simple 8-bit Latin-1 character "ó". VB6 doesn't cope well with multibyte UTF-8 characters; .NET is better. To view UTF-8 data properly, you need to use a UTF-8-compatible text editor.