[VB6] StringBuilder - Fast string concatenation

[Dragokas]

v.2.6.
It's well-tested class for concatenating strings like:

s = s & "one line"
s = s & "two line"
...
s = s & "N line"

but much much more faster than VB runtime do it.

Cases when it is needed sometimes:
Well, e.g., I'm using it to prepare some really huge logs of program in a single 'String' variable (e.g. up to 1 MB.) rather then writing them line by line to file (for performance acceleration purposes, if debug mode of my app. is disabled).
Don't know what else good cases. Better, don't store large data in this way, use suitable tools: arrays, databases ...

Using examples:

Option Explicit

Private Sub Form_Load()
    'init 
    Dim sb As clsStringBuilder
    Set sb = New clsStringBuilder

    'concatenation 
    sb.Append "Very "
    sb.Append "many "
    sb.Append "pieces "
    sb.Append "of data"

    'result 
    Debug.Print "All data: "; sb.ToString
    Debug.Print "Len of data: "; sb.length

    'removing 5 characters from position # 1 
    sb.Remove 1, 5
    Debug.Print "New data: "; sb.ToString

    'inserting string in position # 1 
    sb.Insert 1, "Not "
    Debug.Print "New data: "; sb.ToString

    'overwrite part of the text from position # 1 (same like MID(str,x) = "...") 
    sb.Overwrite 1, "How"
    Debug.Print "New data: "; sb.ToString

    'getting 2 first characters 
    Debug.Print "2 left chars: "; sb.ToStringLeft(2)

    'getting 2 characters from the end 
    Debug.Print "2 end chars: "; sb.ToStringRight(2)

    'getting 2 characters from the middle, beginning from position 6 
    Debug.Print "2 middle chars: "; sb.ToStringMid(6, 2)

    'getting a pointer to a NUL terminated string to use somehow (e.g. write on disk by ptr, WriteFile, e.t.c.) 
    'this method is much faster than .ToString() 
    'warning: you should use this pointer before calling next any method of StringBuilder, that may cause changing its data 
    Debug.Print "ptr to string: "; sb.ToStringPtr

    'replacing the data (same as Clear + Append) 
    sb.StringData = "Anew"
    Debug.Print "New data: "; sb.ToString

    'go to the next line (append CrLf) 
    sb.AppendLine ""
    'append second line with CrLf at the end 
    sb.AppendLine "Second line"
    'append third line without CrLf 
    sb.Append "Third Line"

    Debug.Print sb.ToString

    'clear all data 
    sb.Clear
    Debug.Print "Len of data (after clear): "; sb.length

    'Search samples (by default search is case sensitive) 
    'Set new data 
    sb.StringData = "|textile|Some|text|to|search"
    Debug.Print "New data: "; sb.ToString

    'Simple search ('text' will be found inside 'textile' word) 
    Debug.Print "Position of 'text': " & sb.Find(1, "text")

    'Simple search (start search from position 3) 
    Debug.Print "Position of 'text': " & sb.Find(3, "text")

    Debug.Print "'some' (case sensitive): " & sb.Find(1, "some")
    Debug.Print "'some' (case insensitive): " & sb.Find(1, "some", , vbTextCompare)

    'Search by delimiter 
    Debug.Print "searching for |text|: " & sb.Find(1, "text", "|")

    'Search for empty string, saved with delimiter | 
    Debug.Print "empty string (delim = '|'): " & sb.Find(1, "", "|")

    'Undo operations 
    sb.StringData = "Some data "
    Debug.Print "Orig. string: " & sb.ToString

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

    sb.Insert 6, "bad "
    Debug.Print "After Insert: " & sb.ToString
    'or you can use .UndoInsert 
    sb.Undo
    Debug.Print "After Undo:   " & sb.ToString

    sb.Overwrite 1, "Here"
    Debug.Print "After Overwrite: " & sb.ToString
    'or you can use .UndoOverwrite 
    sb.Undo
    Debug.Print "After Undo:      " & sb.ToString

    sb.Remove 2, 5
    Debug.Print "After Remove: " & sb.ToString
    'or you can use .UndoRemove 
    sb.Undo
    Debug.Print "After Undo:   " & sb.ToString

    'when you finished work with the class 
    Set sb = Nothing

    Unload Me
End Sub

Result:

All data: Very many pieces of data
Len of data: 24
New data: many pieces of data
New data: Not many pieces of data
New data: How many pieces of data
2 left chars: Ho
2 end chars: ta
2 middle chars: an
ptr to string: 228655136
New data: Anew
Anew
Second line
Third Line
Len of data (after clear): 0
New data: |textile|Some|text|to|search
Position of 'text': 2
Position of 'text': 15
'some' (case sensitive): 0
'some' (case insensitive): 10
searching for |text|: 15
empty string (delim = '|'): 1
Orig. string: Some data
After Append: Some data remove
After Undo: Some data
After Insert: Some bad data
After Undo: Some data
After Overwrite: Here data
After Undo: Some data
After Remove: Sata
After Undo: Some data

Copyrights: VolteFace (Fork by Dragokas)