clap-digest

Integration to choose digest with clap on a CLI.

Features

1. A [clap::ValueEnum][] implementation for the different digest algorithm types:

   ```rust use clap::builder::{Arg, ArgAction, EnumValueParser}; use clap_digest::Digest;

   Arg::new("digest") .action(ArgAction::Set) .value_parser(EnumValueParser::::new()) ```

2. Ready-to-use [clap::Arg][] implementations:

   ```rust use clap::{Command, ValueEnum}; use clap_digest::{Digest, DynDigest};

   let cli = Command::new("myapp") .arg(clapdigest::arg::digest().requiredunlesspresent("list-digests")) .arg(clapdigest::arg::list_digests());

   let args = cli.getmatchesfrom(["myapp", "--list-digests"]);

   if args.getflag("list-digests") { for digest in Digest::valuevariants() { println!("{digest}"); } } else { let digest = *args .get_one::("digest") .expect("has default via clap");

   todo!()
   

   } ```

   See the clap_digest::arg module for more information.

3. A conversion from [clap_digest::Digest][] to [digest::DynDigest][]:

   ```rust use clap_digest::{Digest, DynDigest};

   // fn doing some hashing, using any DynDigest implementation fn dynhash(hasher: &mut dyn DynDigest, data: &[u8]) -> String { hasher.update(data); let hash = hasher.finalizereset(); hash.iter().map(|byte| format!("{:02x}", byte)).collect() }

   // parse user-supplied CLI input to clapdigest::Digest with clap // suppose user runs this with: command --digest MD5 // let args = cli.getmatches(); let digest = *args.get_one::("digest").unwrap();

   // convert to DynDigest let mut digest: Box = digest.into();

   // use with hashing function let hash = dynhash(digest.asmut(), b"foo");

   assert_eq!(hash, "acbd18db4cc2f85cedef654fccc4a4d8"); ```

4. Digest algorithm groups are feature-gated. Use cargo feature clap-digest for a complete listing. At least one digest algorithm group feature must be chosen. To limit the digest algorithm families you want to support in your crate, define your own features, e.g.:

   toml [features] default = ["sha2"] md5 = ["clap-digest/md5"] sha1 = ["clap-digest/sha1"] sha2 = ["clap-digest/sha2"]

Example

For a complete CLI example, see examples/cksum.rs.

```console $ cargo run --example cksum -- -d SHA1 Cargo.toml 7a96ee85606435fe1f39c3fa6bdf4cf9bbbc338c Cargo.toml

$ sha1sum Cargo.toml 7a96ee85606435fe1f39c3fa6bdf4cf9bbbc338c Cargo.toml

$ cargo run --example cksum -- -d MD5 Cargo.toml | md5sum -c Cargo.toml: OK ```

List all supported algorithms:

console $ cargo run --example cksum -- --list-digests BLAKE2b512 BLAKE2s256 BLAKE3 ...

All algorithm groups are feature-gated, so you can choose:

console $ cargo run --example cksum --no-default-features --features md5,sha1,sha2 -- --list-digests MD5 SHA1 SHA224 SHA256 SHA384 SHA512 SHA512/224 SHA512/256