Index

uuid4

use crate::prelude::*;

impl Uuid {
    /// Creates a random UUID.
    ///
    /// This uses the [`getrandom`] crate to utilise the operating system's RNG
    /// as the source of random numbers. If you'd like to use a custom generator,
    /// don't use this method: use the `rand::Rand trait`'s `rand()` method instead.
    ///
    /// Note that usage of this method requires the `v4` feature of this crate
    /// to be enabled.
    ///
    /// # Examples
    ///
    /// Basic usage:
    ///
    /// ```
    /// use uuid::Uuid;
    ///
    /// let uuid = Uuid::new_v4();
    /// ```
    ///
    /// [`getrandom`]: https://crates.io/crates/getrandom
    /// [`rand`]: https://crates.io/crates/rand
    // TODO: change signature to support uuid's Error.
    pub fn new_v4() -> Result<Uuid, getrandom::Error> {
        let mut bytes = [0u8; 16];
        getrandom::getrandom(&mut bytes)?;

        let uuid = crate::builder::Builder::from_bytes(bytes)
            .set_variant(Variant::RFC4122)
            .set_version(Version::Random)
            .build();
        Ok(uuid)
    }
}

#[cfg(test)]
mod tests {
    use crate::prelude::*;

    #[test]
    fn test_new() {
        let uuid = Uuid::new_v4().unwrap();

        assert_eq!(uuid.get_version(), Some(Version::Random));
        assert_eq!(uuid.get_variant(), Some(Variant::RFC4122));
    }

    #[test]
    fn test_get_version() {
        let uuid = Uuid::new_v4().unwrap();

        assert_eq!(uuid.get_version(), Some(Version::Random));
        assert_eq!(uuid.get_version_num(), 4)
    }
}

use uuid::{Builder, Uuid, Variant, Version};

fn main() {
    let bytes = [0u8; 16];
    let uuid = Builder::from_bytes(bytes)
        .set_variant(Variant::RFC4122)
        .set_version(Version::Random)
        .build();
    println!("{:?}", uuid);
}

TL;DR version, use https://github.com/rust-random/getrandom

fn get_random_buf() -> Result<[u8; 32], getrandom::Error> {
    let mut buf = [0u8; 32];
    getrandom::getrandom(&mut buf)?;
    Ok(buf)
}

fn get_random_buf() -> Result<[u8; 32], getrandom::Error> {
    let mut buf = [0u8; 32]; // [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
    getrandom::getrandom(&mut buf)?;
    Ok(buf)
}
fn main() {
   let data = get_random_buf();
   println!("{:?}", data);
}

Ok([126, 92, 235, 31, 246, 57, 236, 225, 86, 14, 23, 58, 212, 8, 140, 7, 140, 79, 110, 92, 208, 180, 208, 201, 122, 9, 181, 33, 241, 82, 3, 91])

How to generate an array of random bytes from a seed?
https://stackoverflow.com/questions/62308909/how-to-generate-an-array-of-random-bytes-from-a-seed/62309203

use rand::{rngs::StdRng, RngCore, SeedableRng};
use uuid::{Builder, Variant, Version};

fn main() {
    let seed = [0u8; 32];
    let mut rng: StdRng = SeedableRng::from_seed(seed);
    let mut bytes = [0u8; 16];
    rng.fill_bytes(&mut bytes);
    let uuid = Builder::from_bytes(bytes)
        .set_variant(Variant::RFC4122)
        .set_version(Version::Random)
        .build();
    println!("{:?}", uuid);
}

Generating seed 32 length seed for testing:

use rand::Rng;

fn main() {
    let mut rng = rand::thread_rng();


    let mut randvec:Vec<u8> = Vec::new();
    let mut counter = 0;
    let result = loop {
        counter += 1;
        let n1: u8 = rng.gen();
        randvec.push(n1);

        if counter == 32 {
            break randvec;
        }
    };
    println!("{:?}", result);
}

Generating from seed:

use rand::{rngs::StdRng, RngCore, SeedableRng, Rng};
use uuid::{Builder, Variant, Version};

fn main() {
    let mut rng = rand::thread_rng();


    let mut randarray: [u8;32] = [0; 32];
    let mut counter = 0;
    let result = loop {
        let n1: u8 = rng.gen();
        randarray[counter] = n1;
        counter += 1;

        if counter == 32 {
            break randarray;
        }
    };
    println!("{:?}", result);
    let seed = result;
    let mut rng: StdRng = SeedableRng::from_seed(seed);
    let mut bytes = [0u8; 16];
    rng.fill_bytes(&mut bytes);
    let uuid = Builder::from_bytes(bytes)
        .set_variant(Variant::RFC4122)
        .set_version(Version::Random)
        .build();
    println!("{:?}", uuid);
}

Getting a vect, converting to array than give it as seed:

use rand::{rngs::StdRng, RngCore, SeedableRng, Rng};
use uuid::{Builder, Variant, Version};

fn main() {
    let mut rng = rand::thread_rng();


    let mut randvec:Vec<u8> = Vec::new();
    let mut counter = 0;
    let result_vec = loop {
        counter += 1;
        let n1: u8 = rng.gen();
        randvec.push(n1);

        if counter == 32 {
            break randvec;
        }
    };
    println!("{:?}", result_vec);

    // convert vector seed to array seed
    let mut seed = [0u8; 32];
    let mut counter = 0;
    for v in result_vec.iter() {
        seed[counter] = *v;
        counter += 1;

    }

    println!("{:?}", seed);
    // feed the array seed
    let mut rng: StdRng = SeedableRng::from_seed(seed);
    let mut bytes = [0u8; 16];
    rng.fill_bytes(&mut bytes);
    let uuid = Builder::from_bytes(bytes)
        .set_variant(Variant::RFC4122)
        .set_version(Version::Random)
        .build();
    println!("{:?}", uuid);
}

Output:
[181, 127, 162, 178, 55, 217, 237, 166, 94, 82, 24, 25, 232, 11, 245, 41, 217, 227, 197, 179, 230, 106, 189, 82, 8, 177, 146, 76, 183, 228, 96, 76]
[181, 127, 162, 178, 55, 217, 237, 166, 94, 82, 24, 25, 232, 11, 245, 41, 217, 227, 197, 179, 230, 106, 189, 82, 8, 177, 146, 76, 183, 228, 96, 76]
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