VERSION 1.0 CLASS BEGIN MultiUse = -1 'True END Attribute VB_Name = "Base64" Attribute VB_GlobalNameSpace = False Attribute VB_Creatable = False Attribute VB_PredeclaredId = False Attribute VB_Exposed = False Option Explicit Private Const clOneMask = 16515072 '000000 111111 111111 111111 Private Const clTwoMask = 258048 '111111 000000 111111 111111 Private Const clThreeMask = 4032 '111111 111111 000000 111111 Private Const clFourMask = 63 '111111 111111 111111 000000 Private Const clHighMask = 16711680 '11111111 00000000 00000000 Private Const clMidMask = 65280 '00000000 11111111 00000000 Private Const clLowMask = 255 '00000000 00000000 11111111 Private Const cl2Exp18 = 262144 '2 to the 18th power Private Const cl2Exp12 = 4096 '2 to the 12th Private Const cl2Exp6 = 64 '2 to the 6th Private Const cl2Exp8 = 256 '2 to the 8th Private Const cl2Exp16 = 65536 '2 to the 16th Private cbTransTo(63) As Byte Private cbTransFrom(255) As Byte Private clPowers8(255) As Long Private clPowers16(255) As Long Private clPowers6(63) As Long Private clPowers12(63) As Long Private clPowers18(63) As Long Private Sub Class_Initialize() Dim lTemp As Long For lTemp = 0 To 63 'Fill the translation table. Select Case lTemp Case 0 To 25 cbTransTo(lTemp) = 65 + lTemp 'A - Z Case 26 To 51 cbTransTo(lTemp) = 71 + lTemp 'a - z Case 52 To 61 cbTransTo(lTemp) = lTemp - 4 '1 - 0 Case 62 cbTransTo(lTemp) = 43 'Chr(43) = "+" Case 63 cbTransTo(lTemp) = 47 'Chr(47) = "/" End Select Next lTemp For lTemp = 0 To 255 'Fill the lookup tables. clPowers8(lTemp) = lTemp * cl2Exp8 clPowers16(lTemp) = lTemp * cl2Exp16 Next lTemp For lTemp = 0 To 63 clPowers6(lTemp) = lTemp * cl2Exp6 clPowers12(lTemp) = lTemp * cl2Exp12 clPowers18(lTemp) = lTemp * cl2Exp18 Next lTemp For lTemp = 0 To 255 'Fill the translation table. Select Case lTemp Case 65 To 90 cbTransFrom(lTemp) = lTemp - 65 'A - Z Case 97 To 122 cbTransFrom(lTemp) = lTemp - 71 'a - z Case 48 To 57 cbTransFrom(lTemp) = lTemp + 4 '1 - 0 Case 43 cbTransFrom(lTemp) = 62 'Chr(43) = "+" Case 47 cbTransFrom(lTemp) = 63 'Chr(47) = "/" End Select Next lTemp End Sub Public Function Encode(sString As String) As String Dim bTrans(63) As Byte, bOut() As Byte, bIn() As Byte, lOutSize As Long Dim lChar As Long, lTrip As Long, iPad As Integer, lLen As Long, lTemp As Long, lPos As Long iPad = Len(sString) Mod 3 'See if the length is divisible by 3 If iPad Then 'If not, figure out the end pad and resize the input. iPad = 3 - iPad sString = sString & String(iPad, Chr(0)) End If bIn = StrConv(sString, vbFromUnicode) 'Load the input string. lLen = ((UBound(bIn) + 1) \ 3) * 4 'Length of resulting string. lTemp = lLen \ 72 'Added space for vbCrLfs. lOutSize = ((lTemp * 2) + lLen) - 1 'Calculate the size of the output buffer. ReDim bOut(lOutSize) 'Make the output buffer. lLen = 0 'Reusing this one, so reset it. For lChar = LBound(bIn) To UBound(bIn) Step 3 lTrip = clPowers16(bIn(lChar)) + clPowers8(bIn(lChar + 1)) + bIn(lChar + 2) 'Combine the 3 bytes lTemp = lTrip And clOneMask 'Mask for the first 6 bits bOut(lPos) = cbTransTo(lTemp \ cl2Exp18) 'Shift it down to the low 6 bits and get the value lTemp = lTrip And clTwoMask 'Mask for the second set. bOut(lPos + 1) = cbTransTo(lTemp \ cl2Exp12) 'Shift it down and translate. lTemp = lTrip And clThreeMask 'Mask for the third set. bOut(lPos + 2) = cbTransTo(lTemp \ cl2Exp6) 'Shift it down and translate. bOut(lPos + 3) = cbTransTo(lTrip And clFourMask) 'Mask for the low set. If lLen = 68 Then 'Ready for a newline bOut(lPos + 4) = 13 'Chr(13) = vbCr bOut(lPos + 5) = 10 'Chr(10) = vbLf lLen = 0 'Reset the counter lPos = lPos + 6 Else lLen = lLen + 4 lPos = lPos + 4 End If Next lChar If bOut(lOutSize) = 10 Then lOutSize = lOutSize - 2 'Shift the padding chars down if it ends with CrLf. If iPad = 1 Then 'Add the padding chars if any. bOut(lOutSize) = 61 'Chr(61) = "=" ElseIf iPad = 2 Then bOut(lOutSize) = 61 bOut(lOutSize - 1) = 61 End If Encode = StrConv(bOut, vbUnicode) 'Convert back to a string and return it. End Function Public Function Decode(sString As String) As String Dim bOut() As Byte, bIn() As Byte, lQuad As Long, iPad As Integer, lChar As Long, lPos As Long, sOut As String Dim lTemp As Long sString = Replace(sString, vbCr, vbNullString) 'Get rid of the vbCrLfs. These could be in... sString = Replace(sString, vbLf, vbNullString) 'either order. lTemp = Len(sString) Mod 4 'Test for valid input. If lTemp Then Call Err.Raise(vbObjectError, "MyDecode", "Input string is not valid Base64.") End If If InStrRev(sString, "==") Then 'InStrRev is faster when you know it's at the end. iPad = 2 'Note: These translate to 0, so you can leave them... ElseIf InStrRev(sString, "=") Then 'in the string and just resize the output. iPad = 1 End If bIn = StrConv(sString, vbFromUnicode) 'Load the input byte array. ReDim bOut((((UBound(bIn) + 1) \ 4) * 3) - 1) 'Prepare the output buffer. For lChar = 0 To UBound(bIn) Step 4 lQuad = clPowers18(cbTransFrom(bIn(lChar))) + clPowers12(cbTransFrom(bIn(lChar + 1))) + _ clPowers6(cbTransFrom(bIn(lChar + 2))) + cbTransFrom(bIn(lChar + 3)) 'Rebuild the bits. lTemp = lQuad And clHighMask 'Mask for the first byte bOut(lPos) = lTemp \ cl2Exp16 'Shift it down lTemp = lQuad And clMidMask 'Mask for the second byte bOut(lPos + 1) = lTemp \ cl2Exp8 'Shift it down bOut(lPos + 2) = lQuad And clLowMask 'Mask for the third byte lPos = lPos + 3 Next lChar sOut = StrConv(bOut, vbUnicode) 'Convert back to a string. If iPad Then sOut = Left$(sOut, Len(sOut) - iPad) 'Chop off any extra bytes. Decode = sOut End Function