Option Explicit

Public Function Base64Encode2(Infile As String,Outfile As String)
Dim FnumIn As Integer,FnumOut As Integer
Dim mInByte(3) As Byte,mOutByte(4) As Byte
Dim myByte As Byte
Dim i As Integer,LineLen As Integer,j As Integer
FnumIn = FreeFile()
Open Infile For Binary As #FnumIn
FnumOut = FreeFile()
Open Outfile For Binary As #FnumOut
While Not EOF(FnumIn)
    i = 0
    Do While i < 3
    Get #FnumIn,myByte
    If Not EOF(FnumIn) Then
        mInByte(i) = myByte
        i = i + 1
    Else
        Exit Do
    End If
    Loop
    Base64EncodeByte mInByte,mOutByte,i
    For j = 0 To 3
        Put #FnumOut,mOutByte(j)
    Next j
    LineLen = LineLen + 1
    If LineLen * 4 > 70 Then
        Put #FnumOut,vbCrLf
        LineLen = 0
    End If
Wend
Close (FnumOut)
Close (FnumIn)
End Function

Private Sub Base64EncodeByte(mInByte() As Byte,mOutByte() As Byte,Num As Integer)
Dim tByte As Byte
Dim i As Integer

If Num = 1 Then
    mInByte(1) = 0
    mInByte(2) = 0
ElseIf Num = 2 Then
    mInByte(2) = 0
End If

tByte = mInByte(0) And &HFC
mOutByte(0) = tByte / 4
tByte = ((mInByte(0) And &H3) * 16) + (mInByte(1) And &HF0) / 16
mOutByte(1) = tByte
tByte = ((mInByte(1) And &HF) * 4) + ((mInByte(2) And &HC0) / 64)
mOutByte(2) = tByte
tByte = (mInByte(2) And &H3F)
mOutByte(3) = tByte

For i = 0 To 3
    If mOutByte(i) >= 0 And mOutByte(i) <= 25 Then
        mOutByte(i) = mOutByte(i) + Asc("A")
    ElseIf mOutByte(i) >= 26 And mOutByte(i) <= 51 Then
        mOutByte(i) = mOutByte(i) - 26 + Asc("a")
    ElseIf mOutByte(i) >= 52 And mOutByte(i) <= 61 Then
        mOutByte(i) = mOutByte(i) - 52 + Asc("0")
    ElseIf mOutByte(i) = 62 Then
        mOutByte(i) = Asc("+")
    Else
        mOutByte(i) = Asc("/")
    
    End If
Next i

If Num = 1 Then
    mOutByte(2) = Asc("=")
    mOutByte(3) = Asc("=")
ElseIf Num = 2 Then
    mOutByte(3) = Asc("=")
End If
End Sub


Public Function Base64Decode2(Infile As String,FnumOut As Integer
Dim mInByte(4) As Byte,mOutByte(3) As Byte
Dim myByte As Byte
Dim i As Integer,j As Integer
Dim ByteNum As Integer
FnumIn = FreeFile()
Open Infile For Binary As #FnumIn
FnumOut = FreeFile()
Open Outfile For Binary As #FnumOut

While Not EOF(FnumIn)
    i = 0
    Do While i < 4
    Get #FnumIn,myByte
    If Not EOF(FnumIn) Then
        If myByte <> &HA And myByte <> &HD Then
        '把回车符和换行符去掉
            mInByte(i) = myByte
            i = i + 1
        End If
    Else
        Exit Do
    End If
    Loop
    Base64DecodeByte mInByte,ByteNum
    
    For j = 0 To 2 - ByteNum
        Put #FnumOut,mOutByte(j)
    Next j
    'LineLen = LineLen + 1
Wend
Close (FnumOut)
Close (FnumIn)
End Function

Private Sub Base64DecodeByte(mInByte() As Byte,ByteNum As Integer)
Dim tByte As Byte
Dim i As Integer
ByteNum = 0
For i = 0 To 3
    If mInByte(i) >= Asc("A") And mInByte(i) <= Asc("Z") Then
        mInByte(i) = mInByte(i) - Asc("A")
    ElseIf mInByte(i) >= Asc("a") And mInByte(i) <= Asc("z") Then
        mInByte(i) = mInByte(i) - Asc("a") + 26
    ElseIf mInByte(i) >= Asc("0") And mInByte(i) <= Asc("9") Then
        mInByte(i) = mInByte(i) - Asc("0") + 52
    ElseIf mInByte(i) = Asc("+") Then
        mInByte(i) = 62
    ElseIf mInByte(i) = Asc("/") Then
        mInByte(i) = 63
    Else '"="
        ByteNum = ByteNum + 1
        mInByte(i) = 0
    End If
Next i
'取前六位
tByte = (mInByte(0) And &H3F) * 4 + (mInByte(1) And &H30) / 16
'0的六位和1的前两位
mOutByte(0) = tByte
tByte = (mInByte(1) And &HF) * 16 + (mInByte(2) And &H3C) / 4
'1的后四位和2的前四位
mOutByte(1) = tByte
tByte = (mInByte(2) And &H3) * 64 + (mInByte(3) And &H3F)
mOutByte(2) = tByte
'2的后两位和3的六位
End Sub

'Private Sub cmdBase64_Click(Index As Integer)
'If Index = 0 Then
'    Call Base64Encode2(App.Path & "\121.JPG",App.Path & "\out.txt")
'Else
'    Call Base64Decode2(App.Path & "\out.txt",App.Path & "\in3.JPG")
'End If
'End Sub