BASE64 (FUN)¶

FUNCTION BASE64 : PT_SIZE

encodes 8 bit binary data into ASCII data

A text block (string, binary, array of bytes) will be base64 encoded. The maximum of the block is set in the TextBlockSize parameter. This size can be changed but must be divisible by 3.

If the text block is only a part of a text and followed by more text, the size must be TextBlockSize.iBlockSize and the isLastBlock variable must be set to FALSE. If a text is not followed by another block, the specific length of it must be used and isLastBlock has to be set to TRUE, as shown in the following example. The reason is three 8-bit letters will become four 6-bit letters. If only two 8-Bit letters are remaining at the end, the encoded text is filled with „=“. This must only be at the end of a text.

Example:

StringToConvert : PT_SIZE;
EncodedString  : PT_SIZE;
byError        : BYTE;
sText          : STRING := 'This is a test string.';

StringToConvert.uiSize := LEN(sText); (* When another block follows, use the size TextBlockSize.iBlockSize
                                      and set isLastBlock to FALSE. *)
StringToConvert.pString := ADR(sText);
EncodedString := Base64(TextToEncode := StringToConvert, isLastBlock := TRUE, pbyError := ADR(byError));

InOut:

Scope	Name	Type	Comment
Return	BASE64	PT_SIZE	A structure with a pointer to the text and its size (comprising the terminating character)
Input	TextToEncode	PT_SIZE	The text block which should be encoded
	isLastBlock	BOOL	TRUE: The current text block is the end of a text FALSE: The current text block is just a small text
	pbyError	POINTER TO BYTE	0: No error 1: Text block is too long 2: Not divisible through 3 4: Empty string