BinToBase64.fmfn

/*
  ------------------------------------------------------------------------------
  Purpose: Converts binary text of 0's and 1's to Base64
  Author: J. Michael Tritchler
  Notes: This function was developed as part of importing and
              exporting the contents of an ASCII text file stored
              in a container field
  Parameters:
         text - The binary text to convert to Base64
  Data Type Returned:
         text
  Variables:
         $$currBin - stores the current six 0's and 1's from the binary
                           text
         $$padding - stores the single of double equal signs that are
                             appended to the end of the base64 text to
                             inticate if the last character was padded with
                             two 0's or four 0's
         $$text64 - base64 representation of the binary text
         ~return - Returns the base64 representation of the binary
                      text
  Revision:
         Last change: 27/09/2015 by JMT
         ::
         27/09/2015 - JMT - Wrote original script
  ------------------------------------------------------------------------------
*/

Let (
	[
		// Grab the first six bits from the binary text
		$$curBin = Left ( text ; 6 );

		// If the binary text only contains 2 bits, set the padding to two
		// equal signs and pad the binary text with four 0's
		$$curBin = If( Length( text ) = 2; Let ( $$padding = "==" ; $$curBin & "0000" ) ; $$curBin ) ;

		// If the binary text only contains 2 bits, set the padding to one
		// equal sign and pad the binary text with two 0's
		$$curBin = If( Length( text ) = 4; Let ( $$padding = "=" ; $$curBin & "00" ) ; $$curBin );

		// Convert the current 6-bit binary number to the base64 character
		// and add it to the end of the base64 text
		$$text64 = $$text64 & Case (
					Exact ( $$curBin ; "000000" ) ; "A"; 
					Exact ( $$curBin ; "000001" ) ; "B"; 
					Exact ( $$curBin ; "000010" ) ; "C"; 
					Exact ( $$curBin ; "000011" ) ; "D";
					Exact ( $$curBin ; "000100" ) ; "E"; 
					Exact ( $$curBin ; "000101" ) ; "F"; 
					Exact ( $$curBin ; "000110" ) ; "G"; 
					Exact ( $$curBin ; "000111" ) ; "H"; 
					Exact ( $$curBin ; "001000" ) ; "I"; 
					Exact ( $$curBin ; "001001" ) ; "J"; 
					Exact ( $$curBin ; "001010" ) ; "K"; 
					Exact ( $$curBin ; "001011" ) ; "L"; 
					Exact ( $$curBin ; "001100" ) ; "M"; 
					Exact ( $$curBin ; "001101" ) ; "N"; 
					Exact ( $$curBin ; "001110" ) ; "O"; 
					Exact ( $$curBin ; "001111" ) ; "P"; 
					Exact ( $$curBin ; "010000" ) ; "Q"; 
					Exact ( $$curBin ; "010001" ) ; "R"; 
					Exact ( $$curBin ; "010010" ) ; "S"; 
					Exact ( $$curBin ; "010011" ) ; "T"; 
					Exact ( $$curBin ; "010100" ) ; "U"; 
					Exact ( $$curBin ; "010101" ) ; "V"; 
					Exact ( $$curBin ; "010110" ) ; "W"; 
					Exact ( $$curBin ; "010111" ) ; "X"; 
					Exact ( $$curBin ; "011000" ) ; "Y"; 
					Exact ( $$curBin ; "011001" ) ; "Z"; 
					Exact ( $$curBin ; "011010" ) ; "a"; 
					Exact ( $$curBin ; "011011" ) ; "b"; 
					Exact ( $$curBin ; "011100" ) ; "c"; 
					Exact ( $$curBin ; "011101" ) ; "d"; 
					Exact ( $$curBin ; "011110" ) ; "e"; 
					Exact ( $$curBin ; "011111" ) ; "f"; 
					Exact ( $$curBin ; "100000" ) ; "g"; 
					Exact ( $$curBin ; "100001" ) ; "h"; 
					Exact ( $$curBin ; "100010" ) ; "i"; 
					Exact ( $$curBin ; "100011" ) ; "j"; 
					Exact ( $$curBin ; "100100" ) ; "k"; 
					Exact ( $$curBin ; "100101" ) ; "l"; 
					Exact ( $$curBin ; "100110" ) ; "m"; 
					Exact ( $$curBin ; "100111" ) ; "n"; 
					Exact ( $$curBin ; "101000" ) ; "o"; 
					Exact ( $$curBin ; "101001" ) ; "p"; 
					Exact ( $$curBin ; "101010" ) ; "q"; 
					Exact ( $$curBin ; "101011" ) ; "r"; 
					Exact ( $$curBin ; "101100" ) ; "s"; 
					Exact ( $$curBin ; "101101" ) ; "t"; 
					Exact ( $$curBin ; "101110" ) ; "u"; 
					Exact ( $$curBin ; "101111" ) ; "v"; 
					Exact ( $$curBin ; "110000" ) ; "w"; 
					Exact ( $$curBin ; "110001" ) ; "x"; 
					Exact ( $$curBin ; "110010" ) ; "y"; 
					Exact ( $$curBin ; "110011" ) ; "z"; 
					Exact ( $$curBin ; "110100" ) ; "0"; 
					Exact ( $$curBin ; "110101" ) ; "1"; 
					Exact ( $$curBin ; "110110" ) ; "2"; 
					Exact ( $$curBin ; "110111" ) ; "3"; 
					Exact ( $$curBin ; "111000" ) ; "4"; 
					Exact ( $$curBin ; "111001" ) ; "5"; 
					Exact ( $$curBin ; "111010" ) ; "6"; 
					Exact ( $$curBin ; "111011" ) ; "7"; 
					Exact ( $$curBin ; "111100" ) ; "8"; 
					Exact ( $$curBin ; "111101" ) ; "9"; 
					Exact ( $$curBin ; "111110" ) ; "+"; 
					Exact ( $$curBin ; "111111" ) ; "/" );

		// Save the base64 text a local variable so that the global
		// variable can be cleared before exiting the function
		~return = $$text64
	];

		If ( Length ( text ) > 6;

			// Convert the next 6 bits to Base64 if not at the end
			// of the binary text
			BinToBase64 ( Right ( text ; Length ( text ) - 6 ) );

			// Clear the global variables and return the Base64 text if
			// there are no more bits to calculate
			Let(
				[
					~return = ~return & $$padding; // Add padding if necessary
					$$padding = "";
					$$charCnt = "";
					$$text64 = ""
				];
					~return
			)
		)
)