Encode base64

Purpose: Base64 encode.

 encode-base64 <data> to <output data> \
     [ input-length <input length> ]

encode-base64 will encode string <data> into base64 string <output data>.

If "input-length" clause is used, then <input length> is the number of bytes encoded, otherwise the entirety of <data> is encoded.

The result is stored in <output data> (in "to" clause).

Base64-encoded strings are often used where binary data needs to be in a format that complies with certain text-based protocols, such as in attaching documents in email, or embedding binary documents (such as "JPG" images for example) in web pages with "data:image/jpg;base64..." specified, etc.

Examples

An example that encodes a string, decodes, and finally checks if they match:

 // Original string, generally this would be binary data in most cases
 set-string dt ="  oh well  "

 // Encode in base64
 encode-base64 dt to out_dt

 decode-base64 out_dt to new_dt

 if-true dt equal new_dt
     @Success!
 else-if
     @Failure!
 end-if

In the next example, "input-length" clause is used, and only a partial of the input string is encoded, then later compared to the original:

 // Original string, generally this would be binary data in most cases
 set-string dt ="  oh well  "

 // Encode in base64, encode only 6 bytes
 encode-base64 dt input-length 6 to out_dt

 decode-base64 out_dt to new_dt

 // Get length of decoded string
 string-length new_dt to new_len

 if-true new_len not-equal 6
     @Failure!
 else-if
     @Success!
 end-if

 if-true dt equal new_dt length new_len
     @Success!
 else-if
     @Failure! [<<p-out dt>>] [<<p-out new_dt>>]
 end-if