| Base64 encoding and decoding Functions This was edited by myself after I read several base64 encoding and decoding functions.
Because VBScript in the Chinese operating system uses the Unicode Character Set
Many base64 encoding and decoding functions are theoretically correct, but they cannot be run! File Name base64test. asp <% Sbase_64_characters = "abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz0123456789 + /"
Sbase_64_characters = strunicode2ansi (sbase_64_characters) Function strunicodelen (ascontents)
'Calculate the ANSI encoding length of the Unicode string
Ascontents1 = "A" & ascontents
Len1 = Len (ascontents1)
K = 0
For I = 1 to len1
Asc1 = ASC (mid (ascontents1, I, 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 Function strunicode2ansi (ascontents)
'Convert a Unicode-encoded string to an ANSI-encoded string.
Strunicode2ansi = ""
Len1 = Len (ascontents)
For I = 1 to len1
Varchar = mid (ascontents, I, 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 Function stransi2unicode (ascontents)
'Convert an ANSI-encoded string to a Unicode-encoded string.
Stransi2unicode = ""
Len1 = lenb (ascontents)
If len1 = 0 Then exit function
For I = 1 to len1
Varchar = midb (ascontents, I, 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 Function base64encode (ascontents)
'Encode the ANSI encoded string with base64
'Ascontents should be an ANSI encoded string (Binary strings can also be used)
Dim lnposition
Dim lsresult
Dim char1
Dim char2
Dim char3
Dim char4
Dim byte1
Dim byte2
Dim byte3
Dim savebits1
Dim savebits2
Dim lsgroupbinary
Dim lsgroup64
Dim M4, len1, len2 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, chrb (0 ))
'The complement BITs are used to facilitate computation. 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, (Bytes 1 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 'Process the remaining several characters
If m3> 0 then
Lsgroup64 = ""
Lsgroupbinary = midb (ascontents, len2 + 1, 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, (Bytes 1 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) If m3 = 1 then
Lsgroup64 = char1 & char2 & chrb (61) & chrb (61) 'Use = to fill the digits
Else
Lsgroup64 = char1 & char2 & char3 & chrb (61) 'Use = to fill in the digits
End if Lsresult = lsresult & lsgroup64
End if Base64encode = lsresult End Function Function base64decode (ascontents)
'Convert a base64 encoded string to an ANSI encoded string
'Ascontents should also be an ANSI encoded string (Binary strings can also be used)
Dim lsresult
Dim lnposition
Dim lsgroup64, lsgroupbinary
Dim char1, char2, char3, char4
Dim byte1, byte2, byte3
Dim M4, len1, len2 Len1 = lenb (ascontents)
M4 = len1 mod 4 If len1 <1 or M4> 0 then
'String length should be a multiple of 4
Base64decode = ""
Exit Function
End if 'Judge whether the last digit is equal to =
'Determine whether the second to last digit is equal to or not
'Here M4 indicates the number of remaining characters that need to be processed separately.
If midb (ascontents, len1, 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, lnposition, 4)
Char1 = bytes B (sbase_64_characters, midb (lsgroup64, 1, 1)-1
Char2 = bytes B (sbase_64_characters, midb (lsgroup64, 2, 1)-1
Char3 = bytes B (sbase_64_characters, midb (lsgroup64, 3, 1)-1
Char4 = bytes B (sbase_64_characters, midb (lsgroup64, 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 'Process the remaining several characters
If M4> 0 then
Lsgroupbinary = ""
Lsgroup64 = midb (ascontents, len2 + 1, M4) & chrb (65) 'chr (65) = A, converted to 0
If M4 = 2 then' makes up four digits to facilitate computation
Lsgroup64 = lsgroup64 & chrb (65)
End if
Char1 = bytes B (sbase_64_characters, midb (lsgroup64, 1, 1)-1
Char2 = bytes B (sbase_64_characters, midb (lsgroup64, 2, 1)-1
Char3 = bytes B (sbase_64_characters, midb (lsgroup64, 3, 1)-1
Char4 = bytes B (sbase_64_characters, midb (lsgroup64, 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 )) If M4 = 2 then
Lsgroupbinary = byte1
Elseif M4 = 3 then
Lsgroupbinary = byte1 & byte2
End if Lsresult = lsresult & lsgroupbinary
End if Base64decode = lsresult End Function |
