Option Explicit Dim sBASE_64_CHARACTERS As String Public Function strUnicodeLen(ByVal asContents As String) As Long Dim len1,k,i,asc1 As Long '计算unicode字符串的Ansi编码的长度 Dim ascontents1 As String ascontents1 = "a" & asContents len1 = Len(ascontents1) k = 0 For i = 1 To len1 asc1 = Asc(Mid(ascontents1,1)) If asc1 < 0 Then asc1 = 65536 + asc1 If asc1 > 255 Then k = k + 2 Else k = k + 1 End If Next strUnicodeLen = k - 1 End Function Public Function strUnicode2Ansi(ByVal asContents As String) As String '将Unicode编码的字符串，转换成Ansi编码的字符串 Dim len1,i As Long Dim varchar As String Dim varasc As Long Dim varhex,varlow,varhigh As String strUnicode2Ansi = "" len1 = Len(asContents) For i = 1 To len1 varchar = Mid(asContents,1) varasc = Asc(varchar) If varasc < 0 Then varasc = varasc + 65536 If varasc > 255 Then varhex = Hex(varasc) varlow = Left(varhex,2) varhigh = Right(varhex,2) strUnicode2Ansi = strUnicode2Ansi & ChrB("&H" & varlow) & ChrB("&H" & varhigh) Else strUnicode2Ansi = strUnicode2Ansi & ChrB(varasc) End If Next End Function Public Function strAnsi2Unicode(ByVal asContents As String) As String '将Ansi编码的字符串，转换成Unicode编码的字符串 Dim len1,i As Long Dim varchar As String Dim varasc As Long strAnsi2Unicode = "" len1 = LenB(asContents) If len1 = 0 Then Exit Function For i = 1 To len1 varchar = MidB(asContents,1) varasc = AscB(varchar) If varasc > 127 Then strAnsi2Unicode = strAnsi2Unicode & Chr(AscW(MidB(asContents,i + 1,1) & varchar)) i = i + 1 Else strAnsi2Unicode = strAnsi2Unicode & Chr(varasc) End If Next End Function Public Function Base64encode(ByVal asContents As String) As String sBASE_64_CHARACTERS = "AzByCxDwEvFuGtHsIrJqKpLoMnNmOlPkQjRiShTgUfVeWdXcYbZa)(*&>%$#@!+/" sBASE_64_CHARACTERS = strUnicode2Ansi(sBASE_64_CHARACTERS) '将Ansi编码的字符串进行Base64编码 'asContents应当是ANSI编码的字符串（二进制的字符串也可以） asContents = strUnicode2Ansi(asContents) Dim lnPosition As Long Dim lsResult As String Dim Char1 As String Dim Char2 As String Dim Char3 As String Dim Char4 As String Dim Byte1 As Integer Dim Byte2 As Integer Dim Byte3 As Integer Dim SaveBits1 As Integer Dim SaveBits2 As Integer Dim lsGroupBinary As String Dim lsGroup64 As String Dim M4,len1,len2 As Long Dim m3 As Integer len1 = LenB(asContents) If len1 < 1 Then Base64encode = "" Exit Function End If m3 = len1 Mod 3 If m3 > 0 Then asContents = asContents & String(3 - m3,ChrW(0)) '补足位数是为了便于计算 If m3 > 0 Then len1 = len1 + (3 - m3) len2 = len1 - 3 Else len2 = len1 End If lsResult = "" For lnPosition = 1 To len2 Step 3 lsGroup64 = "" lsGroupBinary = MidB(asContents,lnPosition,3) Byte1 = AscB(MidB(lsGroupBinary,1,1)): SaveBits1 = Byte1 And 3 Byte2 = AscB(MidB(lsGroupBinary,2,1)): SaveBits2 = Byte2 And 15 Byte3 = AscB(MidB(lsGroupBinary,3,1)) Char1 = MidB(sBASE_64_CHARACTERS,((Byte1 And 252) / 4) + 1,1) Char2 = MidB(sBASE_64_CHARACTERS,(((Byte2 And 240) / 16) Or (SaveBits1 * 16) And &HFF) + 1,1) Char3 = MidB(sBASE_64_CHARACTERS,(((Byte3 And 192) / 64) Or (SaveBits2 * 4) And &HFF) + 1,1) Char4 = MidB(sBASE_64_CHARACTERS,(Byte3 And 63) + 1,1) lsGroup64 = Char1 & Char2 & Char3 & Char4 lsResult = lsResult & lsGroup64 Next '处理最后剩余的几个字符 If m3 > 0 Then lsGroup64 = "" lsGroupBinary = MidB(asContents,len2 + 1,1) If m3 = 1 Then lsGroup64 = Char1 & Char2 & ChrB(61) & ChrB(61) '用=号补足位数 Else lsGroup64 = Char1 & Char2 & Char3 & ChrB(61) '用=号补足位数 End If lsResult = lsResult & lsGroup64 End If Base64encode = strAnsi2Unicode(lsResult) End Function Public Function Base64decode(ByVal asContents As String) As String '将Base64编码字符串转换成Ansi编码的字符串 'asContents应当也是ANSI编码的字符串（二进制的字符串也可以） sBASE_64_CHARACTERS = "AzByCxDwEvFuGtHsIrJqKpLoMnNmOlPkQjRiShTgUfVeWdXcYbZa)(*&>%$#@!+/" sBASE_64_CHARACTERS = strUnicode2Ansi(sBASE_64_CHARACTERS) asContents = strUnicode2Ansi(asContents) Dim lsResult As String Dim lnPosition As Long Dim lsGroup64,lsGroupBinary As String Dim Char1,Char2,Char3,Char4 As String Dim Byte1,Byte2,Byte3 As String Dim M4,len2 As Long len1 = LenB(asContents) M4 = len1 Mod 4 If len1 < 1 Or M4 > 0 Then '字符串长度应当是4的倍数 Base64decode = "" Exit Function End If '判断最后一位是不是 = 号 '判断倒数第二位是不是 = 号 '这里m4表示最后剩余的需要单独处理的字符个数 If MidB(asContents,1) = ChrB(61) Then M4 = 3 If MidB(asContents,len1 - 1,1) = ChrB(61) Then M4 = 2 If M4 = 0 Then len2 = len1 Else len2 = len1 - 4 End If For lnPosition = 1 To len2 Step 4 lsGroupBinary = "" lsGroup64 = MidB(asContents,4) Char1 = InStrB(sBASE_64_CHARACTERS,MidB(lsGroup64,1)) - 1 Char2 = InStrB(sBASE_64_CHARACTERS,1)) - 1 Char3 = InStrB(sBASE_64_CHARACTERS,1)) - 1 Char4 = InStrB(sBASE_64_CHARACTERS,4,1)) - 1 Byte1 = ChrB(((Char2 And 48) / 16) Or (Char1 * 4) And &HFF) Byte2 = lsGroupBinary & ChrB(((Char3 And 60) / 4) Or (Char2 * 16) And &HFF) Byte3 = ChrB((((Char3 And 3) * 64) And &HFF) Or (Char4 And 63)) lsGroupBinary = Byte1 & Byte2 & Byte3 lsResult = lsResult & lsGroupBinary Next '处理最后剩余的几个字符 If M4 > 0 Then lsGroupBinary = "" lsGroup64 = MidB(asContents,M4) & ChrB(65) 'chr(65)=A，转换成值为0 If M4 = 2 Then '补足4位，是为了便于计算 lsGroup64 = lsGroup64 & ChrB(65) End If Char1 = InStrB(sBASE_64_CHARACTERS,1)) - 1 Byte1 = ChrB(((Char2 And 48) / 16) Or (Char1 * 4) And &HFF) Byte2 = lsGroupBinary & ChrB(((Char3 And 60) / 4) Or (Char2 * 16) And &HFF) Byte3 = ChrB((((Char3 And 3) * 64) And &HFF) Or (Char4 And 63)) If M4 = 2 Then lsGroupBinary = Byte1 ElseIf M4 = 3 Then lsGroupBinary = Byte1 & Byte2 End If lsResult = lsResult & lsGroupBinary End If Base64decode = strAnsi2Unicode(lsResult) End Function