The goal of b64 is to provide a very fast, lightweight, and vectorized base64 encoder and decoder.
Example
Encode to base64 using encode().
Decode using decode(). Note that the returned object will always have the "blob" class. To achieve 0 dependencies, the blob package is only listed as a suggested dependency but if you attach it, its print method will be used.
We can convert the decoded base64 to characters and see how it worked.
rawToChar(decoded[[1]])
#> [1] "Hello, from extendr"Vectorized
Both encode() and decode() are vectorized.
lorem <- unlist(lorem::ipsum(5, 1, 5))
lorem
#> [1] "Elit porttitor litora phasellus primis."
#> [2] "Sit vel natoque eu quisque."
#> [3] "Sit accumsan elementum pharetra aliquet parturient ullamcorper."
#> [4] "Consectetur iaculis nunc elementum."
#> [5] "Dolor donec iaculis sem."
encoded <- encode(lorem)
encoded
#> [1] "RWxpdCBwb3J0dGl0b3IgbGl0b3JhIHBoYXNlbGx1cyBwcmltaXMu"
#> [2] "U2l0IHZlbCBuYXRvcXVlIGV1IHF1aXNxdWUu"
#> [3] "U2l0IGFjY3Vtc2FuIGVsZW1lbnR1bSBwaGFyZXRyYSBhbGlxdWV0IHBhcnR1cmllbnQgdWxsYW1jb3JwZXIu"
#> [4] "Q29uc2VjdGV0dXIgaWFjdWxpcyBudW5jIGVsZW1lbnR1bS4="
#> [5] "RG9sb3IgZG9uZWMgaWFjdWxpcyBzZW0u"We can decode all of these using decode() as well.
decode(encoded)
#> <blob[5]>
#> [1] blob[39 B] blob[27 B] blob[63 B] blob[35 B] blob[24 B]Encoding and decoding files
b64 shines when encoding and decoding files. encode_file() and decode_file() both work by reading a file as a stream making it far faster than the alternative.
tmp <- tempfile()
fp <- "https://github.com/datablist/sample-csv-files/raw/main/files/leads/leads-100000.csv"
download.file(fp, tmp)
bench::mark(
b64 = encode_file(tmp),
base64enc = base64enc::base64encode(tmp)
)
#> Warning: Some expressions had a GC in every iteration; so filtering is
#> disabled.
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc `gc/sec`
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 b64 67.5ms 74.2ms 13.7 24.1MB 1.96
#> 2 base64enc 177.9ms 183.3ms 5.50 66.9MB 11.0While the encoding is very impressive, better yet is the decoding performance.
# create a temp file
tmp2 <- tempfile()
# encode it and write to tmep file
encode_file(tmp) |>
charToRaw() |>
writeBin(tmp2)
bench::mark(
b64 = decode_file(tmp2),
base64enc = base64enc::base64decode(file(tmp2))
)
#> # A tibble: 2 × 6
#> expression min median `itr/sec` mem_alloc `gc/sec`
#> <bch:expr> <bch:tm> <bch:tm> <dbl> <bch:byt> <dbl>
#> 1 b64 43.4ms 51.7ms 19.7 18.1MB 5.63
#> 2 base64enc 356.7ms 373.3ms 2.68 18.1MB 0Alternative engines
Out of the box, b64 provides a number of pre-configured engines that can be used. The function engine() allows you to choose one of these different engines For example, engine("url_safe") provides a standard engine that uses a url-safe alphabet with padding.
url_engine <- engine("url_safe")
url_safe_encoded <- encode("\xfa\xec U", url_engine)
url_safe_encoded
#> [1] "-uwgVQ=="If we try to decode this using the standard engine, we will encounter an error.
decode(url_safe_encoded)
#> Error in decode_(what, eng): Invalid byte 45, offset 0.We can use our new engine to decode it.
decode(url_safe_encoded, url_engine)
#> <blob[1]>
#> [1] blob[4 B]Custom Engines
We can create custom engines with new_engine(). This allows us to provide our on alphabet and configuration.
We can use one of the many predefined alphabets or create one our selves with new_alphabet(). We can also specify our engine config using new_config() which lets us choose whether or not to pad and how to handle decoding.
my_eng <- new_engine(
alphabet("crypt"),
new_config(TRUE, TRUE, "none")
)This engine can be used to encode or decode text.
txt <- "lorem ipsum sit dolor amet"
encode(txt, my_eng)
#> [1] "P4xmNKoUOL/nRKoUQqZo64FjP4xm643hNLE="Compare this to the standard encoder:
encode(txt)
#> [1] "bG9yZW0gaXBzdW0gc2l0IGRvbG9yIGFtZXQ="