// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or

// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license

// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your

// option. This file may not be copied, modified, or distributed

// except according to those terms.

use std::convert::TryFrom as _;

use crate::{

    Error,

    err::IntoResult as _,

    init, p11,

    p11::{PK11_HashBuf, SECOidTag},

};

//

// Constants

//

pub enum HashAlgorithm {

    SHA2_256,

    SHA2_384,

    SHA2_512,

}

const fn hash_alg_to_oid(alg: &HashAlgorithm) -> SECOidTag::Type {

    match alg {

        HashAlgorithm::SHA2_256 => SECOidTag::SEC_OID_SHA256,

        HashAlgorithm::SHA2_384 => SECOidTag::SEC_OID_SHA384,

        HashAlgorithm::SHA2_512 => SECOidTag::SEC_OID_SHA512,

    }

}

#[must_use]

pub const fn hash_alg_to_hash_len(alg: &HashAlgorithm) -> usize {

    match alg {

        HashAlgorithm::SHA2_256 => p11::SHA256_LENGTH as usize,

        HashAlgorithm::SHA2_384 => p11::SHA384_LENGTH as usize,

        HashAlgorithm::SHA2_512 => p11::SHA512_LENGTH as usize,

    }

}

//

// Hash function

//

pub fn hash(alg: &HashAlgorithm, data: &[u8]) -> Result<Vec<u8>, Error> {

    init()?;

    let data_len: i32 = match i32::try_from(data.len()) {

        Ok(data_len) => data_len,

        _ => return Err(Error::Internal),

    };

    let expected_len = hash_alg_to_hash_len(alg);

    let mut digest = vec![0u8; expected_len];

    unsafe {

        PK11_HashBuf(

            hash_alg_to_oid(alg),

            digest.as_mut_ptr(),

            data.as_ptr(),

            data_len,

        )

        .into_result()?;

    };

    Ok(digest)

}