[VB6] StringBuilder - Fast string concatenation

its not support utf-8? i tested cant find utf-8 strings,any sample or class for can compare or find utf-8 string in another utf-8 string?

UTF8?
All internal VB6 strings are unicode.
The conversion from unicode to an UTF8 byte array is only performed when you save it to disk.
When you get/read an byte array containing utf8 the you need to convert it back to unicode.

There are multiple samples on the forum on how to these conversions

Black_Storm, it would be better you describe your entire use case. Some code from you can explain.
Also, are you sure that you provide a substring in the same utf8 format?
Generally, the class is not intended for utf8.

No, you should keep it as it is.
Black_Storm should use the 2 functions already created by Merri

He also asked for UTF8 controls and much more.
He should deal with his data as normal strings and only convert them when receiving the data.

Code:

---

' StrConvUTF8.bas
Option Explicit

Private Declare Function MultiByteToWideChar Lib "kernel32" (ByVal CodePage As Long, ByVal dwFlags As Long, ByVal lpMultiByteStr As Long, ByVal cchMultiByte As Long, ByVal lpWideCharStr As Long, ByVal cchWideChar As Long) As Long
Private Declare Sub PutMem4 Lib "msvbvm60" (ByVal Ptr As Long, ByVal Value As Long)
Private Declare Function SysAllocStringLen Lib "oleaut32" (ByVal Ptr As Long, ByVal Length As Long) As Long
Private Declare Function WideCharToMultiByte Lib "kernel32" (ByVal CodePage As Long, ByVal dwFlags As Long, ByVal lpWideCharStr As Long, ByVal cchWideChar As Long, ByVal lpMultiByteStr As Long, ByVal cchMultiByte As Long, ByVal lpDefaultChar As Long, lpUsedDefaultChar As Long) As Long

Public Function StrConvFromUTF8(Text As String) As String
    ' get length
    Dim lngLen As Long, lngPtr As Long: lngLen = LenB(Text)
    ' has any?
    If lngLen Then
        ' create a BSTR over twice that length
        lngPtr = SysAllocStringLen(0, lngLen * 1.25)
        ' place it in output variable
        PutMem4 VarPtr(StrConvFromUTF8), lngPtr
        ' convert & get output length
        lngLen = MultiByteToWideChar(65001, 0, ByVal StrPtr(Text), lngLen, ByVal lngPtr, LenB(StrConvFromUTF8))
        ' resize the buffer
        StrConvFromUTF8 = Left$(StrConvFromUTF8, lngLen)
    End If
End Function

Public Function StrConvToUTF8(Text As String) As String
    ' get length
    Dim lngLen As Long, lngPtr As Long: lngLen = LenB(Text)
    ' has any?
    If lngLen Then
        ' create a BSTR over twice that length
        lngPtr = SysAllocStringLen(0, lngLen * 1.25)
        ' place it in output variable
        PutMem4 VarPtr(StrConvToUTF8), lngPtr
        ' convert & get output length
        lngLen = WideCharToMultiByte(65001, 0, ByVal StrPtr(Text), Len(Text), ByVal lngPtr, LenB(StrConvToUTF8), ByVal 0&, ByVal 0&)
        ' resize the buffer
        StrConvToUTF8 = LeftB$(StrConvToUTF8, lngLen)
    End If
End Function

---

Cant Undo for Append

Code:

---

  StrEx.Add "remove"
    Debug.Print "After Add: " & StrEx.ToString
    'or you can use .UndoAppend
    StrEx.Undo
 
    Debug.Print "After Undo:  " & StrEx.ToString

---

After Append: Some data remove
After Undo: Some data emove

CHANGE TO

Code:

---

Public Function Undo() As Boolean
    Undo = True
    m_bInRevert = True
    Select Case m_LastOp
        Case StrEx_LAST_Add
            'GetMem2 ByVal StrPtr(vbNullChar), ByVal (m_pMemoryPtr + m_UndoIndexStart * 2)'YOUR CODE
            Lenb2 = m_UndoIndexStart * 2 'I CHANGE IT，abcd
           
        Case StrEx_LAST_INSERT
            Remove m_UndoIndexStart + 1, m_UndoLength
           
        Case StrEx_LAST_OVERWRITE
            Overwrite m_UndoIndexStart + 1, m_UndoText
            m_UndoText = vbNullString
           
        Case StrEx_LAST_REMOVE
            Insert m_UndoIndexStart + 1, m_UndoText
            m_UndoText = vbNullString
           
        Case 0
            Undo = False
    End Select
    m_LastOp = 0 'disallow dual .Undo call
    m_bInRevert = False
End Function

---

Updated.

Quote:

---

' v2.6
' Fixed .Undo method incorrecly work after .Append / .AppendLine (thanks xiaoyao for pointing me about that back in 2021 :)
'
' v2.5
' Improved speed by replacing some RtlMoveMemory by __vbaCopyBytes
'
' v2.4
' Added check & Err.raise to all methods to ensure user doesn't accidentally call this class within Forms' Terminate event.

---

Hello @Dragokas,

I hope this message finds you well.
I was wondering if it would be possible to update your code to support both 32-bit and 64-bit

Hi, phoronex.
Do you mean TwinBasic support?

Thanks for your quick reply
I mean The awesome (clsStringBuilder)

I'm using ms Access VBA

Sorry, I have a very limited time due to the lack of electricity and issues with my UPS device and a bunch of other social problems related to the war.
Also, I didn't touch VBA x64 for a while. Maybe somebody else may pick up the project.

Thanks a lot,
I wish all the best for you.

phoronex, try to rewrite this class for the needs of x64 yourself, it's not that difficult