[RustCrypto]: hex-literal

This crate provides the hex! macro for converting hexadecimal string literals to a byte array at compile time.

It accepts the following characters in the input string:

'0'...'9', 'a'...'f', 'A'...'F' — hex characters which will be used in construction of the output byte array
' ', '\r', '\n', '\t' — formatting characters which will be ignored

Examples

```rust use hex_literal::hex;

// The macro can be used in const contexts const DATA: [u8; 4] = hex!("01020304"); assert_eq!(DATA, [1, 2, 3, 4]);

// Both upper and lower hex values are supported asserteq!(hex!("a1 b2 c3 d4"), [0xA1, 0xB2, 0xC3, 0xD4]); asserteq!(hex!("E5 E6 90 92"), [0xE5, 0xE6, 0x90, 0x92]); assert_eq!(hex!("0a0B 0C0d"), [10, 11, 12, 13]);

// Multi-line literals let bytes1 = hex!(" 00010203 04050607 08090a0b 0c0d0e0f "); assert_eq!( bytes1, [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15], );

// It's possible to use several literals // (results will be concatenated) let bytes2 = hex!( "00010203 04050607" // first half "08090a0b 0c0d0e0f" // second half ); assert_eq!(bytes1, bytes2); ```

Using an unsupported character inside literals will result in a compilation error: rust,compile_fail hex_literal::hex!("АА"); // Cyrillic "А" hex_literal::hex!("11　22"); // Japanese space

Сomments inside literals are not supported: rust,compile_fail hex_literal::hex!("0123 // foo");

Each literal must contain an even number of hex characters: rust,compile_fail hex_literal::hex!( "01234" "567" );

Minimum Supported Rust Version

Rust 1.57 or newer.

In the future, we reserve the right to change MSRV (i.e. MSRV is out-of-scope for this crate's SemVer guarantees), however when we do it will be accompanied by a minor version bump.

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.