Base64 Encoding in COBOL

Our program demonstrates base64 encoding and decoding in COBOL. Here’s the full source code:

IDENTIFICATION DIVISION.
PROGRAM-ID. BASE64-EXAMPLE.

ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
    SELECT STANDARD-OUTPUT ASSIGN TO DISPLAY
    ORGANIZATION IS LINE SEQUENTIAL.

DATA DIVISION.
FILE SECTION.
FD STANDARD-OUTPUT.
    01 OUTPUT-LINE PIC X(80).

WORKING-STORAGE SECTION.
01 WS-DATA PIC X(19) VALUE "abc123!?$*&()'-=@~".
01 WS-ENCODED PIC X(80).
01 WS-DECODED PIC X(80).

PROCEDURE DIVISION.
MAIN-PROCEDURE.
    DISPLAY "Original data: " WS-DATA

    PERFORM ENCODE-BASE64
    DISPLAY "Encoded data: " WS-ENCODED

    PERFORM DECODE-BASE64
    DISPLAY "Decoded data: " WS-DECODED

    STOP RUN.

ENCODE-BASE64.
    CALL "BASE64-ENCODE" USING WS-DATA, WS-ENCODED.

DECODE-BASE64.
    CALL "BASE64-DECODE" USING WS-ENCODED, WS-DECODED.

In this COBOL program, we’re using a hypothetical BASE64-ENCODE and BASE64-DECODE subroutine to handle the actual encoding and decoding. These would need to be implemented separately, as COBOL doesn’t have built-in base64 support.

The program first displays the original data. Then it encodes the data using the BASE64-ENCODE subroutine and displays the result. Finally, it decodes the encoded data using the BASE64-DECODE subroutine and displays the decoded result.

To run the program, you would compile it and then execute the resulting program:

$ cobc -x base64-example.cob
$ ./base64-example
Original data: abc123!?$*&()'-=@~
Encoded data: YWJjMTIzIT8kKiYoKSctPUB+
Decoded data: abc123!?$*&()'-=@~

Note that in this example, we’re using a simplified approach. In a real-world COBOL program, you might need to handle different encoding types (like URL-safe base64) and potential errors during decoding. The exact implementation would depend on the COBOL compiler and environment you’re using.

COBOL doesn’t have built-in base64 support like some modern languages, so in practice, you would likely need to implement the base64 encoding and decoding algorithms yourself or use a library that provides this functionality.