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Base64.bas
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Base64.bas
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Attribute VB_Name = "Base64"
'BASE64编码模块
Option Explicit
'外部直接调用此函数即可
Public Sub Base64Encode(ByRef pbAInput() As Byte, ByRef sOut As String, Optional ByRef sPrexSpace As String = "", Optional ByRef charsPerLine As Integer = 68)
Dim abOut() As Byte, i As Long, s As String
Encode pbAInput, abOut
ByteArrayToString abOut, s
sOut = ""
If Len(s) = 0 Then Exit Sub
'转换为合适的换行模式
If charsPerLine > 0 Then
For i = 1 To Len(s) Step charsPerLine
sOut = sOut & sPrexSpace & Mid(s, i, charsPerLine) & vbCrLf
Next
sOut = Mid(sOut, 1, Len(sOut) - 3)
Else
sOut = s
End If
End Sub
Public Sub ByteArrayToString(ByRef pbArrayInput() As Byte, ByRef strOut As String)
strOut = StrConv(pbArrayInput, vbUnicode)
End Sub
Public Sub Encode(ByRef pbArrayInput() As Byte, ByRef pbArrayOutput() As Byte)
Dim iSizeMod As Integer, lSizeIn As Long, lSizeOut As Long, Index As Long
Dim lIndex2 As Long, lTotal As Long, bBuffer(2) As Byte
Dim mvB64Enc(63) As Byte
Dim iIndex As Integer
For iIndex = 65 To 90
mvB64Enc(iIndex - 65) = iIndex
Next
For iIndex = 97 To 122
mvB64Enc(iIndex - 71) = iIndex
Next
For iIndex = 48 To 57
mvB64Enc(iIndex + 4) = iIndex
Next
mvB64Enc(62) = 43
mvB64Enc(63) = 47
lSizeIn = UBound(pbArrayInput) + 1
iSizeMod = lSizeIn Mod 3
lSizeOut = ((lSizeIn - iSizeMod) \ 3) * 4
If iSizeMod > 0 Then lSizeOut = lSizeOut + 4
ReDim pbArrayOutput(lSizeOut - 1)
If lSizeIn >= 3 Then
lTotal = lSizeIn - iSizeMod - 1
For Index = 0 To lTotal Step 3
bBuffer(0) = pbArrayInput(Index)
bBuffer(1) = pbArrayInput(Index + 1)
bBuffer(2) = pbArrayInput(Index + 2)
pbArrayOutput(lIndex2) = mvB64Enc((bBuffer(0) And &HFC) \ 4)
pbArrayOutput(lIndex2 + 1) = mvB64Enc((bBuffer(0) And &H3) * 16 Or (bBuffer(1) And &HF0) \ 16)
pbArrayOutput(lIndex2 + 2) = mvB64Enc((bBuffer(1) And &HF) * 4 Or (bBuffer(2) And &HC0) \ 64)
pbArrayOutput(lIndex2 + 3) = mvB64Enc((bBuffer(2) And &H3F))
lIndex2 = lIndex2 + 4
Next
End If
Select Case iSizeMod
Case 1
bBuffer(0) = pbArrayInput(lSizeIn - 1)
bBuffer(1) = 0
pbArrayOutput(lIndex2) = mvB64Enc((bBuffer(0) And &HFC) \ 4)
pbArrayOutput(lIndex2 + 1) = mvB64Enc((bBuffer(0) And &H3) * 16 Or (bBuffer(1) And &HF0) \ 16)
pbArrayOutput(lIndex2 + 2) = 61
pbArrayOutput(lIndex2 + 3) = 61
Case 2
bBuffer(0) = pbArrayInput(lSizeIn - 2)
bBuffer(1) = pbArrayInput(lSizeIn - 1)
bBuffer(2) = 0
pbArrayOutput(lIndex2) = mvB64Enc((bBuffer(0) And &HFC) \ 4)
pbArrayOutput(lIndex2 + 1) = mvB64Enc((bBuffer(0) And &H3) * 16 Or (bBuffer(1) And &HF0) \ 16)
pbArrayOutput(lIndex2 + 2) = mvB64Enc((bBuffer(1) And &HF) * 4 Or (bBuffer(2) And &HC0) \ 64)
pbArrayOutput(lIndex2 + 3) = 61
End Select
End Sub