crockford 1.0.1

Provides Crockford Base32 encoding for identifiers (e.g. u64 values).
Documentation

crockford Build Status

Rust Crockford encoding for u64

Crockford Base32 Encoding is most commonly used to make numeric identifiers slightly more user-resistant. Similar to Hashids, the purpose here is to make the identifiers shorter and less confusing. Unlike Hashids, Crockford Base32 does nothing to conceal the real value of the number (beyond the actual encoding, anyway) and the fact that they are sequential is still pretty obvious when you see consecutive identifiers side by side.

This library does not support encoding and decoding of arbitrary data; there is another library for that. Additionally, the spec supports the idea of check digits, but this library currently does not.

The primary purpose of this library is to provide high performance, user-resistant encoding of numeric identifiers. To that end, both encoding and decoding are, in fact, pretty darn fast.

Usage

Encoding

Encoding is a one-step process.

let x = crockford::encode(5111);
assert_eq!("4ZQ", &*x);

If you want lowercase, then... Well, tough. However, we do now support encoding to a buffer of your choice rather than a new one created in the function. Read on to learn about plan B...

Plan B (faster encoding)

Because this is Rust, particular focus is given to runtime efficiency--or, at least, allowing the user to achieve runtime efficiency. As a result, we provide a second, more complicated encoding option.

// The longest possible representation of u64 is 13 digits.
let mut buf = Vec::with_capacity(13);
crockford::encode_into(5111, &mut buf);

let result = std::str::from_utf8(&buf)?;
assert_eq!("4ZQ", result);

This encode_into method also accepts &mut String, if you prefer.

Decoding

Decoding is a two-step process. This is because you can feed any string to the decoder, and the decoder will return an error if you try to convince it that "Hello, world!" is a number. (Hint: it isn't.)

let x = crockford::decode("4zq");
let y = crockford::decode("4ZQ");

assert_eq!(5111, x?);
assert_eq!(5111, y?);

So, step one is to call the decode function. Step two is to match/verify/unwrap/throw away the output.

Development

Mostly a note on fuzzing to supplement my own memory...

When tinkering with encoding or decoding, it may be helpful to throw new changes at the fuzzer. This has only been tested on macOS, but the commands are:

cargo fuzz run encode
cargo fuzz run decode

The fuzzer can be pretty good at making up nonsensical test cases for invalid data.

License

Licensed under either of

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.