graviola 0.3.4

// Written for Graviola by Joe Birr-Pixton, 2024.
// SPDX-License-Identifier: Apache-2.0 OR ISC OR MIT-0

macro_rules! CH {
    ($x:expr, $y:expr, $z:expr) => {
        ($x & $y) ^ (!$x & $z)
    };
}

macro_rules! MAJ {
    ($x:expr, $y:expr, $z:expr) => {
        ($x & $y) ^ ($x & $z) ^ ($y & $z)
    };
}

macro_rules! BSIG0 {
    ($x:expr) => {
        $x.rotate_right(28) ^ $x.rotate_right(34) ^ $x.rotate_right(39)
    };
}

macro_rules! BSIG1 {
    ($x:expr) => {
        $x.rotate_right(14) ^ $x.rotate_right(18) ^ $x.rotate_right(41)
    };
}

macro_rules! SSIG0 {
    ($x:expr) => {
        $x.rotate_right(1) ^ $x.rotate_right(8) ^ ($x >> 7)
    };
}

macro_rules! SSIG1 {
    ($x:expr) => {
        $x.rotate_right(19) ^ $x.rotate_right(61) ^ ($x >> 6)
    };
}

fn sha512_compress_block(state: &mut [u64; 8], block: &[u8]) {
    let mut a = state[0];
    let mut b = state[1];
    let mut c = state[2];
    let mut d = state[3];
    let mut e = state[4];
    let mut f = state[5];
    let mut g = state[6];
    let mut h = state[7];

    // This is a 16-word window into the whole W array.
    let mut w: [u64; 16] = [0; 16];

    for t in 0..80 {
        // For W[0..16] we process the input into W.
        // For W[16..80] we compute the next W value:
        //
        // W[t] = SSIG1(W[t - 2]) + W[t - 7] + SSIG0(W[t - 15]) + W[t - 16];
        //
        // But all W indices are reduced mod 16 into our window.
        let w_t = if t < 16 {
            let w_t = u64::from_be_bytes(block[t * 8..(t + 1) * 8].try_into().unwrap());
            w[t] = w_t;
            w_t
        } else {
            let w_t = SSIG1!(w[(t - 2) % 16])
                .wrapping_add(w[(t - 7) % 16])
                .wrapping_add(SSIG0!(w[(t - 15) % 16]))
                .wrapping_add(w[(t - 16) % 16]);
            w[t % 16] = w_t;
            w_t
        };

        let t1 = h
            .wrapping_add(BSIG1!(e))
            .wrapping_add(CH!(e, f, g))
            .wrapping_add(K[t])
            .wrapping_add(w_t);
        let t2 = BSIG0!(a).wrapping_add(MAJ!(a, b, c));
        h = g;
        g = f;
        f = e;
        e = d.wrapping_add(t1);
        d = c;
        c = b;
        b = a;
        a = t1.wrapping_add(t2);
    }

    state[0] = state[0].wrapping_add(a);
    state[1] = state[1].wrapping_add(b);
    state[2] = state[2].wrapping_add(c);
    state[3] = state[3].wrapping_add(d);
    state[4] = state[4].wrapping_add(e);
    state[5] = state[5].wrapping_add(f);
    state[6] = state[6].wrapping_add(g);
    state[7] = state[7].wrapping_add(h);
}

pub(crate) fn sha512_compress_blocks(state: &mut [u64; 8], blocks: &[u8]) {
    debug_assert!(blocks.len().is_multiple_of(128));

    for block in blocks.chunks_exact(128) {
        sha512_compress_block(state, block);
    }
}

static K: [u64; 80] = [
    0x428a2f98d728ae22,
    0x7137449123ef65cd,
    0xb5c0fbcfec4d3b2f,
    0xe9b5dba58189dbbc,
    0x3956c25bf348b538,
    0x59f111f1b605d019,
    0x923f82a4af194f9b,
    0xab1c5ed5da6d8118,
    0xd807aa98a3030242,
    0x12835b0145706fbe,
    0x243185be4ee4b28c,
    0x550c7dc3d5ffb4e2,
    0x72be5d74f27b896f,
    0x80deb1fe3b1696b1,
    0x9bdc06a725c71235,
    0xc19bf174cf692694,
    0xe49b69c19ef14ad2,
    0xefbe4786384f25e3,
    0x0fc19dc68b8cd5b5,
    0x240ca1cc77ac9c65,
    0x2de92c6f592b0275,
    0x4a7484aa6ea6e483,
    0x5cb0a9dcbd41fbd4,
    0x76f988da831153b5,
    0x983e5152ee66dfab,
    0xa831c66d2db43210,
    0xb00327c898fb213f,
    0xbf597fc7beef0ee4,
    0xc6e00bf33da88fc2,
    0xd5a79147930aa725,
    0x06ca6351e003826f,
    0x142929670a0e6e70,
    0x27b70a8546d22ffc,
    0x2e1b21385c26c926,
    0x4d2c6dfc5ac42aed,
    0x53380d139d95b3df,
    0x650a73548baf63de,
    0x766a0abb3c77b2a8,
    0x81c2c92e47edaee6,
    0x92722c851482353b,
    0xa2bfe8a14cf10364,
    0xa81a664bbc423001,
    0xc24b8b70d0f89791,
    0xc76c51a30654be30,
    0xd192e819d6ef5218,
    0xd69906245565a910,
    0xf40e35855771202a,
    0x106aa07032bbd1b8,
    0x19a4c116b8d2d0c8,
    0x1e376c085141ab53,
    0x2748774cdf8eeb99,
    0x34b0bcb5e19b48a8,
    0x391c0cb3c5c95a63,
    0x4ed8aa4ae3418acb,
    0x5b9cca4f7763e373,
    0x682e6ff3d6b2b8a3,
    0x748f82ee5defb2fc,
    0x78a5636f43172f60,
    0x84c87814a1f0ab72,
    0x8cc702081a6439ec,
    0x90befffa23631e28,
    0xa4506cebde82bde9,
    0xbef9a3f7b2c67915,
    0xc67178f2e372532b,
    0xca273eceea26619c,
    0xd186b8c721c0c207,
    0xeada7dd6cde0eb1e,
    0xf57d4f7fee6ed178,
    0x06f067aa72176fba,
    0x0a637dc5a2c898a6,
    0x113f9804bef90dae,
    0x1b710b35131c471b,
    0x28db77f523047d84,
    0x32caab7b40c72493,
    0x3c9ebe0a15c9bebc,
    0x431d67c49c100d4c,
    0x4cc5d4becb3e42b6,
    0x597f299cfc657e2a,
    0x5fcb6fab3ad6faec,
    0x6c44198c4a475817,
];