'Author: Shannon D Larratt
'Source: http://www.powerbasic.com/support/forums/Forum5/HTML/000403.html
' 
FUNCTION Encode64(InputStr AS STRING) AS STRING
    DIM State AS INTEGER
    DIM i AS INTEGER
    DIM Base64(0 TO 63) AS STRING
    DIM current AS INTEGER
    DIM old AS INTEGER
    DIM first_new AS STRING
    DIM second_new AS STRING
    DIM OUTPUTer AS STRING

    FOR r=0 TO 63
        Base64(r) = READ$(r+1)
    NEXT

DATA "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M"
DATA "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"
DATA "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m"
DATA "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"
DATA "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "+", "/"

    FOR i = 1 TO LEN(InputStr)
         State = State + 1
         SELECT CASE State
         CASE 1
             current = ASC(MID$(InputStr, i, 1))
             first_new = Base64((INT(current / 4) AND &H3F))
             OUTPUTer = OUTPUTer & first_new
         CASE 2
             current = ASC(MID$(InputStr, i, 1))
             first_new = Base64((((old * 16) AND &H30) OR ((INT(current / 16) AND &HF))))
             OUTPUTer = OUTPUTer & first_new
         CASE 3:
             current = ASC(MID$(InputStr, i, 1))
             first_new = Base64((((old * 4) AND &H3C) OR ((INT(current / 64) AND &H3))))
             second_new = Base64((current AND &H3F))
             OUTPUTer = OUTPUTer & first_new & second_new
             State = 0
         END SELECT
         old = current
     NEXT
     SELECT CASE State
     CASE 1
         first_new = Base64(((old * 16) AND &H30))
         OUTPUTer = OUTPUTer & first_new & "=="
     CASE 2
         first_new = Base64(((old * 4) AND &H3C))
         OUTPUTer = OUTPUTer & first_new & "="
     END SELECT
     Encode64 = OUTPUTer
END FUNCTION

FUNCTION Decode64(InputStr AS STRING) AS STRING
    DIM x AS INTEGER
    DIM y AS INTEGER
    DIM OUTPUTer AS STRING
    DIM Base64(0 TO 63) AS STRING
    DIM Found AS INTEGER
    DIM g AS INTEGER
    DIM Group AS LONG
    FOR r=0 TO 63
        Base64(r) = READ$(r+1)
    NEXT

DATA "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M"
DATA "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"
DATA "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m"
DATA "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"
DATA "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "+", "/"

    g = 18
    FOR x = 1 TO LEN(InputStr)
       current_char = ASC(MID$(InputStr, x, 1))

       Found = 0
       FOR y = 0 TO 63
          IF Base64(y) = CHR$(current_char) THEN
             Found = 1
             EXIT FOR
          END IF
       NEXT
       IF Found = 1 THEN
          Group = (Group OR (y * (2 ^ g)))
       END IF
       g = g - 6
       IF g < 0 THEN
          outputer = outputer & CHR$(INT((Group AND 16711680) / (65536)))
          outputer = outputer & CHR$(INT((Group AND 65280) / (256)))
          outputer = outputer & CHR$(Group AND 255)
          Group = 0
          g = 18
       END IF
    NEXT
    Decode64 = outputer
    EXIT FUNCTION
END FUNCTION