provekit-skyscraper 0.1.0

Skyscraper hash function implementation over BN254
Documentation 
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use {
    crate::generic,
    core::array,
    fp_rounding::{with_rounding_mode, RoundingGuard, Zero},
};

pub fn compress_many(messages: &[u8], hashes: &mut [u8]) {
    unsafe {
        with_rounding_mode((messages, hashes), move |guard, (messages, hashes)| {
            generic::compress_many(|input| compress(guard, input), messages, hashes)
        });
    }
}

#[inline(always)]
fn compress(guard: &RoundingGuard<Zero>, input: [[[u64; 4]; 2]; 3]) -> [[u64; 4]; 3] {
    generic::compress(|x| square(guard, x), input)
}

#[inline(always)]
fn square(guard: &RoundingGuard<Zero>, n: [[u64; 4]; 3]) -> [[u64; 4]; 3] {
    let [a, b, c] = n;
    let v = array::from_fn(|i| std::simd::u64x2::from_array([b[i], c[i]]));
    let (a, v) = bn254_multiplier::montgomery_square_log_interleaved_3(guard, a, v);
    let b = v.map(|e| e[0]);
    let c = v.map(|e| e[1]);
    [a, b, c]
}

#[cfg(test)]
mod tests {
    use {
        super::*,
        proptest::{
            collection::vec,
            prelude::{any, Strategy},
            proptest,
        },
    };

    fn random_input() -> impl Strategy<Value = Vec<u8>> {
        (1usize..=10).prop_flat_map(|chunks| vec(any::<u8>(), chunks * 64))
    }

    #[test]
    fn test_eq_ref() {
        proptest!(|(input in random_input())| {
            let mut r = vec![0; input.len() / 2];
            let mut e = vec![0; input.len() / 2];
            crate::reference::compress_many(&input, &mut e);
            compress_many(&input, &mut r);
            assert_eq!(r, e);
        });
    }
}