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Encodes and decodes base64 strings.

+ Code Snippet

REM *************************************************
REM * Original Author: Randy Charles Morin
REM * Author's Website: http://www.kbcafe.com
REM *
REM * Ported from C++ to DBP
REM *
REM * Converted By: Phaelax
REM * Website: http://cca-software.com
REM *************************************************



test$ = "This is a TEST!"
print test$
encoded$ = encode64$(test$)
print encoded$
print decode64$(encoded$)

suspend for key


rem Encodes a string to base64
rem returns an encoded string
function encode64$(encode as string)
   b1 as byte
   b2 as byte
   b3 as byte
   value$ = ""

   if len(encode) = 0 then exitfunction value$

   for i=1 to len(encode) step 3

      b1 = 0
      b2 = 0
      b3 = 0

      b1 = asc(mid$(encode,i))

      if (i+1 <= len(encode)) then b2 = asc(mid$(encode,i+1))
      if (i+2 <= len(encode)) then b3 = asc(mid$(encode,i+2))

      b4 as byte
      b5 as byte
      b6 as byte
      b7 as byte

      b4 = b1>>2
      b5 = ((b1&&0x3)<<4) || (b2>>4)
      b6 = ((b2&&0xf)<<2) || (b3>>6)
      b7 = b3&&0x3f

      value$ = value$ + encodeByte$(b4)
      value$ = value$ + encodeByte$(b5)

      if i+1 <= len(encode)
         value$ = value$ + encodeByte$(b6)
      else
         value$ = value$ + "="
      endif

      if i+2 <= len(encode)
         value$ = value$ + encodeByte$(b7)
      else
         value$ = value$ + "="
      endif

      if i mod 76 = 0
         value$ = value$ + chr$(13)+chr$(10)
      endif

   next i

endfunction value$


rem Decodes a string to base64
rem returns a decoded string
function decode64$(decode as string)
   b1 as byte
   b2 as byte
   b3 as byte
   value$ = ""
   temp$ = ""

   for j = 1 to len(decode)
      if isBase64(mid$(decode,j)) then temp$ = temp$ + mid$(decode,j)
   next j

   if len(temp$) = 0 then exitfunction value$

   for i = 1 to len(temp$) step 4
      c1$ = "A"
      c2$ = "A"
      c3$ = "A"
      c4$ = "A"

      c1$ = mid$(temp$, i)

      if i+1 <= len(temp$) then c2$ = mid$(temp$,i+1)
      if i+2 <= len(temp$) then c3$ = mid$(temp$,i+2)
      if i+3 <= len(temp$) then c4$ = mid$(temp$,i+3)

      b1 as byte
      b2 as byte
      b3 as byte
      b4 as byte

      b1 = decodeChar(c1$)
      b2 = decodeChar(c2$)
      b3 = decodeChar(c3$)
      b4 = decodeChar(c4$)

      value$ = value$ + chr$(b1<<2 || b2>>4)

      if c3$ <> "=" then value$ = value$ + chr$(((b2&&0xf)<<4) || (b3>>2))
      if c4$ <> "=" then value$ = value$ + chr$(((b3&&0x3)<<6) || b4)
   next i

endfunction value$



rem private helper function
rem technically, its a 6-bit pattern
rem with the two higher bits as 0
rem byte as input
rem returns a character
function encodeByte$(b as byte)
   if b < 26 then exitfunction chr$(asc("A")+b)
   if b < 52 then exitfunction chr$(asc("a")+(b-26))
   if b < 62 then exitfunction chr$(asc("0")+(b-52))
   if b = 62 then exitfunction "+"
endfunction "/"


rem private helper function
rem character as input
rem returns byte value of decoded char
function decodeChar(c as string)
   if c >= "A" and c <= "Z"
      v = asc(c)-asc("A")
      exitfunction v
   endif
   if c >= "a" and c <= "z"
      v = asc(c)-asc("a")+26
      exitfunction v
   endif
   if c >= "0" and c <= "9"
      v = asc(c)-asc("0")+52
      exitfunction v
   endif
   if c = "+" then exitfunction 62
endfunction 63


rem private helper function
rem checks if the character is a
rem valid base64 character
rem returns true or false
function isBase64(c as string)
   if c >= "A" and c <= "Z" then exitfunction 1
   if c >= "a" and c <= "z" then exitfunction 1
   if c >= "0" and c <= "9" then exitfunction 1
   if c = "+" then exitfunction 1
   if c = "/" then exitfunction 1
   if c = "=" then exitfunction 1
endfunction 0

You can use this website to check values if you want.
Javazoom's base64 converter

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Nice! Just need to find a use for it.

-Martin

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when you send attachments via the internet, you could encode them with Base64 encoding, basically many attachments are not compatible for transport over the SMTP protocol, so Base64 is handy at making sure your file is sent with corruption or atleast thats the theory lol

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sorry, WITHOUT corruption lol

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the downside though is that it will inflate your attachments to about 33% larger than its original size, but the advantages out way the disadvantages.