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`base85`

The base85 library provides predicates for encoding and decoding data in the Base85 (Ascii85) format. Ascii85 is used in PostScript and PDF files. The encoding uses printable ASCII characters from ! (33) to u (117). A special shortcut z represents four zero bytes. For more details, see for example:

https://en.wikipedia.org/wiki/Ascii85

API documentation

Open the [../../apis/library_index.html#base85](../../apis/library_index.html#base85) link in a web browser.

Loading

To load all entities in this library, load the loader.lgt utility file:

| ?- logtalk_load(base85(loader)).

Testing

To test this library predicates, load the tester.lgt file:

| ?- logtalk_load(base85(tester)).

Encoding

Encoding a list of bytes in Base85 format is accomplished by the `base85::generate/2` predicate. For example:

| ?- atom_codes('Man ', Bytes), base85::generate(atom(Base85), Bytes). Base85 = '9jqo^' Bytes = [77,97,110,32] yes

Four zero bytes are encoded as the special character z:

| ?- base85::generate(atom(Base85), [0, 0, 0, 0]). Base85 = 'z' yes

Decoding

Decoding of Base85 data is accomplished using the `base85::parse/2` predicate. For example:

| ?- base85::parse(atom('9jqo^'), Bytes), atom_codes(Atom, Bytes). Atom = 'Man ' Bytes = [77,97,110,32] yes

The parser also accepts input with optional <~ and ~> delimiters:

| ?- base85::parse(atom('<~9jqo^~>'), Bytes), atom_codes(Atom, Bytes). Atom = 'Man ' Bytes = [77,97,110,32] yes