Package 'b64'

Standard base64 alphabets

Description

Create an alphabet from a set of standard base64 alphabets, or use your own.

Usage

alphabet(which = "standard")

new_alphabet(chars)

Arguments

which	default "standard". Which base64 alphabet to use. See details for other values.
chars	a character scalar contains 64 unique characters.

Details

• "bcrypt": bcrypt alphabet

• "bin_hex": alphabet used in BinHex 4.0 files

• "crypt": crypt(3) alphabet (with . and / as the first two characters)

• "imap_mutf7": alphabet used in IMAP-modified UTF-7 (with + and ,)

• "standard": standard alphabet (with + and /) specified in RFC 4648

• "url_safe": URL-safe alphabet (with - and _) specified in RFC 4648

See base64 crate from where these definitions come.

Value

an object of class alphabet

Examples

alphabet("standard")
alphabet("bcrypt")
alphabet("bin_hex")
alphabet("crypt")
alphabet("imap_mutf7")
alphabet("url_safe")

new_alphabet("qwertyuiop[]asdfghjklzxcvbnmQWERTYUIOPASDFGHJKLZXCVBNM1234567890")

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Utility Functions

Description

Functions to perform common tasks when working with base64 encoded strings.

Usage

b64_chunk(encoded, width)

b64_wrap(chunks, newline)

Arguments

encoded	a character vector of base64 encoded strings.
width	a numeric scalar defining the width of the chunks. Must be divisible by 4.
chunks	a character vector of base64 encoded strings.
newline	a character scalar defining the newline character.

Details

b64_chunk() splits a character vector of base64 encoded strings into chunks of a specified width.

b64_wrap() wraps a character vector of base64 encoded strings with a newline character.

Value

• b64_chunk() returns a list of character vectors.

• b64_wrap() returns a scalar character vector.

Examples

encoded <- encode("Hello, world!")
chunked <- b64_chunk(encoded, 4)
chunked

b64_wrap(chunked, "\n")

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Encode and decode using base64

Description

Encode and decode using base64

Usage

encode(what, eng = engine())

decode(what, eng = engine())

encode_file(path, eng = engine())

decode_file(path, eng = engine())

Arguments

what	a character, raw, or blob vector
eng	a base64 engine. See engine() for details.
path	a path to a base64 encoded file.

Value

Both encode() and decode() are vectorized. They will return a character and blob vector the same length as what, respectively.

Examples

# encode hello world
encoded <- encode("Hello world")
encoded

# decode to a blob
decoded <- decode(encoded)
decoded

# convert back to a character
rawToChar(decoded[[1]])

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Create an encoding engine

Description

Create an encoding engine

Usage

engine(which = "standard")

new_engine(.alphabet = alphabet(), .config = new_config())

Arguments

which	default "standard". The base64 encoding engine to be used. See details for more.
.alphabet	an object of class alphabet as created with alphabet() or new_alphabet()
.config	an object of class engine_config as created with new_config()

Details

Engines

By default, the "standard" base64 engine is used which is specified in RFC 4648.

Additional pre-configured base64 engines are provided these are:

• "standard_no_pad": uses the standard engine without padding

• "url_safe": uses a url-safe alphabet with padding

• "url_safe_no_pad": uses a url-safe alphabet without padding

See base64 crate for more.

Value

an object of class engine.

Examples

engine()
new_engine(alphabet("bcrypt"), new_config())

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Create a custom encoding engine

Description

Create a custom encoding engine

Usage

new_config(
  encode_padding = TRUE,
  decode_padding_trailing_bits = FALSE,
  decode_padding_mode = c("canonical", "indifferent", "none")
)

Arguments

encode_padding	default TRUE add 1-2 trailing = to pad results
decode_padding_trailing_bits	default FALSE. "If invalid trailing bits are present and this is true, those bits will be silently ignored." (See details for reference).
decode_padding_mode	default "canonical". Other values are "indifferent" and "none". See details for more.

Details

See base64 crate for more details.

Decode Padding Modes

There are three modes that can be used for decode_padding_mode argument.

• "canonical": padding must consist of 0, 1, or 2 = characters

• "none": there must be no padding characters present

• "indifferent": canonical padding is used, but omitted padding characters are also permitted

Value

an object of class engine_config

Examples

# create a new nonsensicle config
new_config(FALSE, TRUE, "none")

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