直接复制源码另存为 `cStringBuilder.cls` 然后引入 vb ide 即可使用
vbs 可用 dotnet 组件试下n
VERSION 1.0 CLASS
BEGIN
MultiUse = -1 'True
Persistable = 0 'NotPersistable
DataBindingBehavior = 0 'vbNone
DataSourceBehavior = 0 'vbNone
MTSTransactionMode = 0 'NotAnMTSObject
END
Attribute VB_Name = "cStringBuilder"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = True
Attribute VB_PredeclaredId = False
Attribute VB_Exposed = False
Option Explicit
' ======================================================================================
' Name: vbAccelerator cStringBuilder
' Author: Steve McMahon (steve@vbaccelerator.com)
' Date: 1 January 2002
'
' Copyright ?2002 Steve McMahon for vbAccelerator
' --------------------------------------------------------------------------------------
' Visit vbAccelerator - advanced free source code for VB programmers
' http://vbaccelerator.com
' --------------------------------------------------------------------------------------
'
' VB can be slow to append strings together because of the continual
' reallocation of string size. This class pre-allocates a string in
' blocks and hence removes the performance restriction.
'
' Quicker insert and remove is also possible since string space does
' not have to be reallocated.
'
' Example:
' Adding "http://vbaccelerator.com/" 10,000 times to a string:
' Standard VB: 34s
' This Class: 0.35s
'
' ======================================================================================
Private Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
(pDst As Any, pSrc As Any, ByVal ByteLen As Long)
Private m_sString As String
Private m_iChunkSize As Long
Private m_iPos As Long
Private m_iLen As Long
Public Property Get Length() As Long
Length = m_iPos \ 2
End Property
Public Property Get Capacity() As Long
Capacity = m_iLen \ 2
End Property
Public Property Get ChunkSize() As Long
' Return the unicode character chunk size:
ChunkSize = m_iChunkSize \ 2
End Property
Public Property Let ChunkSize(ByVal iChunkSize As Long)
' Set the chunksize. We multiply by 2 because internally
' we are considering bytes:
m_iChunkSize = iChunkSize * 2
End Property
Public Property Get toString() As String
' The internal string:
If m_iPos > 0 Then
toString = Left$(m_sString, m_iPos \ 2)
End If
End Property
Public Property Let TheString(ByRef sThis As String)
Dim lLen As Long
' Setting the string:
lLen = LenB(sThis)
If lLen = 0 Then
'Clear
m_sString = ""
m_iPos = 0
m_iLen = 0
Else
If m_iLen < lLen Then
' Need to expand string to accommodate:
Do
m_sString = m_sString & Space$(m_iChunkSize \ 2)
m_iLen = m_iLen + m_iChunkSize
Loop While m_iLen < lLen
End If
CopyMemory ByVal StrPtr(m_sString), ByVal StrPtr(sThis), lLen
m_iPos = lLen
End If
End Property
Public Sub Clear()
m_sString = ""
m_iPos = 0
m_iLen = 0
End Sub
Public Sub AppendNL(ByRef sThis As String)
Append sThis
Append vbCrLf
End Sub
Public Sub Append(ByRef sThis As String)
Dim lLen As Long
Dim lLenPlusPos As Long
' Append an item to the string:
lLen = LenB(sThis)
lLenPlusPos = lLen + m_iPos
If lLenPlusPos > m_iLen Then
Dim lTemp As Long
lTemp = m_iLen
Do While lTemp < lLenPlusPos
lTemp = lTemp + m_iChunkSize
Loop
m_sString = m_sString & Space$((lTemp - m_iLen) \ 2)
m_iLen = lTemp
End If
CopyMemory ByVal UnsignedAdd(StrPtr(m_sString), m_iPos), ByVal StrPtr(sThis), lLen
m_iPos = m_iPos + lLen
End Sub
Public Sub AppendByVal(ByVal sThis As String)
Append sThis
End Sub
Public Sub Insert(ByVal iIndex As Long, ByRef sThis As String)
Dim lLen As Long
Dim lPos As Long
Dim lSize As Long
' is iIndex within bounds?
If (iIndex * 2 > m_iPos) Then
Err.Raise 9
Else
lLen = LenB(sThis)
If (m_iPos + lLen) > m_iLen Then
m_sString = m_sString & Space$(m_iChunkSize \ 2)
m_iLen = m_iLen + m_iChunkSize
End If
' Move existing characters from current position
lPos = UnsignedAdd(StrPtr(m_sString), iIndex * 2)
lSize = m_iPos - iIndex * 2
' moving from iIndex to iIndex + lLen
CopyMemory ByVal UnsignedAdd(lPos, lLen), ByVal lPos, lSize
' Insert new characters:
CopyMemory ByVal lPos, ByVal StrPtr(sThis), lLen
m_iPos = m_iPos + lLen
End If
End Sub
Public Sub InsertByVal(ByVal iIndex As Long, ByVal sThis As String)
Insert iIndex, sThis
End Sub
Public Sub Remove(ByVal iIndex As Long, ByVal lLen As Long)
Dim lSrc As Long
Dim lDst As Long
Dim lSize As Long
' is iIndex within bounds?
If (iIndex * 2 > m_iPos) Then
Err.Raise 9
Else
' is there sufficient length?
If ((iIndex + lLen) * 2 > m_iPos) Then
Err.Raise 9
Else
' Need to copy characters from iIndex*2 to m_iPos back by lLen chars:
lSrc = UnsignedAdd(StrPtr(m_sString), (iIndex + lLen) * 2)
lDst = UnsignedAdd(StrPtr(m_sString), iIndex * 2)
lSize = (m_iPos - (iIndex + lLen) * 2)
CopyMemory ByVal lDst, ByVal lSrc, lSize
m_iPos = m_iPos - lLen * 2
End If
End If
End Sub
Public Function Find(ByVal sToFind As String, _
Optional ByVal lStartIndex As Long = 1, _
Optional ByVal compare As VbCompareMethod = vbTextCompare _
) As Long
Dim lInstr As Long
If (lStartIndex > 0) Then
lInstr = InStr(lStartIndex, m_sString, sToFind, compare)
Else
lInstr = InStr(m_sString, sToFind, compare)
End If
If (lInstr < m_iPos \ 2) Then
Find = lInstr
End If
End Function
Public Sub HeapMinimize()
Dim iLen As Long
' Reduce the string size so only the minimal chunks
' are allocated:
If (m_iLen - m_iPos) > m_iChunkSize Then
iLen = m_iLen
Do While (iLen - m_iPos) > m_iChunkSize
iLen = iLen - m_iChunkSize
Loop
m_sString = Left$(m_sString, iLen \ 2)
m_iLen = iLen
End If
End Sub
Private Function UnsignedAdd(Start As Long, Incr As Long) As Long
' This function is useful when doing pointer arithmetic,
' but note it only works for positive values of Incr
If Start And &H80000000 Then 'Start < 0
UnsignedAdd = Start + Incr
ElseIf (Start Or &H80000000) < -Incr Then
UnsignedAdd = Start + Incr
Else
UnsignedAdd = (Start + &H80000000) + (Incr + &H80000000)
End If
End Function
Private Sub Class_Initialize()
' The default allocation: 8192 characters.
m_iChunkSize = 16384
End Sub
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