Base64是网络上最常见的用于传输8Bit字节代码的编码方式之一.它要求把每三个8bit的字节转化为四个6bit的字节,六位字节的最高两位是零,转化后的的编码只能是以下字符:A-Z,a-z,0-9,+,/Base64編碼規范參考RFC2045,rfc2046
Public Function Base64Encode(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 FunctionPrivate Sub Base64EncodeByte(mInByte() As Byte, mOutByte() As Byte, Num As Integer)
Dim tByte As Byte
Dim i As IntegerIf Num = 1 Then
mInByte(1) = 0
mInByte(2) = 0
ElseIf Num = 2 Then
mInByte(2) = 0
End IftByte = 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) = tByteFor 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 iIf Num = 1 Then
mOutByte(2) = Asc("=")
mOutByte(3) = Asc("=")
ElseIf Num = 2 Then
mOutByte(3) = Asc("=")
End If
End Sub
Public Function Base64Decode(Infile As String, Outfile As String)
Dim FnumIn As Integer, FnumOut As Integer
Dim mInByte(4) As Byte, mOutByte(3) As Byte
Dim myByte As Byte
Dim i As Integer, LineLen As Integer, j As Integer
Dim ByteNum As Integer
FnumIn = FreeFile()
Open Infile For Binary As #FnumIn
FnumOut = FreeFile()
Open Outfile For Binary As #FnumOutWhile 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, mOutByte, ByteNum
For j = 0 To 2 - ByteNum
Put #FnumOut, , mOutByte(j)
Next j
'LineLen = LineLen + 1
Wend
Close (FnumOut)
Close (FnumIn)
End FunctionPrivate Sub Base64DecodeByte(mInByte() As Byte, mOutByte() 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不知道和不合你意:)
Public Function Base64Encode(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 FunctionPrivate Sub Base64EncodeByte(mInByte() As Byte, mOutByte() As Byte, Num As Integer)
Dim tByte As Byte
Dim i As IntegerIf Num = 1 Then
mInByte(1) = 0
mInByte(2) = 0
ElseIf Num = 2 Then
mInByte(2) = 0
End IftByte = 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) = tByteFor 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 iIf Num = 1 Then
mOutByte(2) = Asc("=")
mOutByte(3) = Asc("=")
ElseIf Num = 2 Then
mOutByte(3) = Asc("=")
End If
End Sub
Public Function Base64Decode(Infile As String, Outfile As String)
Dim FnumIn As Integer, FnumOut As Integer
Dim mInByte(4) As Byte, mOutByte(3) As Byte
Dim myByte As Byte
Dim i As Integer, LineLen As Integer, j As Integer
Dim ByteNum As Integer
FnumIn = FreeFile()
Open Infile For Binary As #FnumIn
FnumOut = FreeFile()
Open Outfile For Binary As #FnumOutWhile 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, mOutByte, ByteNum
For j = 0 To 2 - ByteNum
Put #FnumOut, , mOutByte(j)
Next j
'LineLen = LineLen + 1
Wend
Close (FnumOut)
Close (FnumIn)
End FunctionPrivate Sub Base64DecodeByte(mInByte() As Byte, mOutByte() 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不知道和不合你意:)
如 10101101 10111010 01110110
----------------- --------
这里是一个中文字[8位高一位不为0] 这是一个英文字母[高一位为0]可以转成00101011 00011011 00101001 00110110
------ ------ ------ ------ =>这里正好是上面的 那27位值
2B 1B 2A 36以下是 10 进制码表中的索引
43 27 42 54
对应码表中的值
r b q 2所以上面的24位编码,编码后值为 rbq2解码同理把rbq2的二进制位连接上再重组得到三个 8位值,得出原码
很明白了吧,呵呵