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//! HKDF sha256.

use cryptraits::kdf::Kdf as KdfTrait;
use hkdf::Hkdf;
use sha2::Sha256;
use zeroize::Zeroize;

use crate::errors::KdfError;

#[derive(Zeroize)]
#[zeroize(drop)]
pub struct Kdf(#[zeroize(skip)] Hkdf<Sha256>);

impl KdfTrait for Kdf {
    type E = KdfError;

    fn new(salt: Option<&[u8]>, data: &[u8]) -> Self {
        Self(Hkdf::<Sha256>::new(salt, data))
    }

    fn expand(&self, info: &[u8], okm: &mut [u8]) -> Result<(), Self::E> {
        self.0.expand(info, okm).or(Err(KdfError::InvalidLength))
    }
}