bytecheck is a type validation framework for Rust.

bytecheck in action

```rust use bytecheck::CheckBytes;

[derive(CheckBytes, Debug)]

struct Test { a: u32, b: bool, c: char, }

fn main() { // This type is laid out as (u32, char, bool) unsafe { // These are valid bytes for (0, 'x', true) Test::check_bytes( &[ 0u8, 0u8, 0u8, 0u8, 0x78u8, 0u8, 0u8, 0u8, 1u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8 ] as *const u8, &() ).unwrap();

    // Changing the bytes for the u32 is OK, any bytes are a valid u32
    Test::check_bytes(
        &[
            42u8, 16u8, 20u8, 3u8, 0x78u8, 0u8, 0u8, 0u8,
            1u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
        ] as *const u8,
        &()
    ).unwrap();

    // Characters outside the valid ranges are invalid
    Test::check_bytes(
        &[
            0u8, 0u8, 0u8, 0u8, 0x00u8, 0xd8u8, 0u8, 0u8,
            1u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
        ] as *const u8,
        &()
    ).unwrap_err();
    Test::check_bytes(
        &[
            0u8, 0u8, 0u8, 0u8, 0x00u8, 0x00u8, 0x11u8, 0u8,
            1u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
        ] as *const u8,
        &()
    ).unwrap_err();

    // 0 is a valid boolean value (false) but 2 is not
    Test::check_bytes(
        &[
            0u8, 0u8, 0u8, 0u8, 0x78u8, 0u8, 0u8, 0u8,
            0u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
        ] as *const u8,
        &()
    ).unwrap();
    Test::check_bytes(
        &[
            0u8, 0u8, 0u8, 0u8, 0x78u8, 0u8, 0u8, 0u8,
            2u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
        ] as *const u8,
        &()
    ).unwrap_err();
}

} ```