cthash 0.9.0

use crate::block_api::eager_split_pad;

/// Compute SHA-224 digest.
/// # Examples
/// ```
/// use cthash::sha2_224;
/// const H: [u8; 28] = sha2_224(b"data");
/// ```
pub const fn sha2_224(input: &[u8]) -> [u8; 28] {
    // SHA-224 IV
    let mut state = [0xc1059ed8, 0x367cd507, 0x3070dd17, 0xf70e5939, 0xffc00b31, 0x68581511, 0x64f98fa7, 0xbefa4fa4];
    sha256_pad_and_run(input, &mut state);

    let mut out = [0u8; 28];
    let mut i = 0;
    while i < 7 {
        out.as_chunks_mut().0[i] = state[i].to_be_bytes();
        i += 1;
    }
    out
}

/// Compute SHA-256 digest.
/// # Examples
/// ```
/// use cthash::sha2_256;
/// const H: [u8; 32] = sha2_256(b"data");
/// ```
pub const fn sha2_256(input: &[u8]) -> [u8; 32] {
    // SHA-256 IV
    let mut state = [0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a, 0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19];
    sha256_pad_and_run(input, &mut state);

    let mut out = [0u8; 32];
    let mut i = 0;
    while i < 8 {
        out.as_chunks_mut().0[i] = state[i].to_be_bytes();
        i += 1;
    }
    out
}

/// Compute SHA-384 digest.
/// # Examples
/// ```
/// use cthash::sha2_384;
/// const H: [u8; 48] = sha2_384(b"data");
/// ```
pub const fn sha2_384(input: &[u8]) -> [u8; 48] {
    // SHA-384 IV
    let mut state = [
        0xcbbb9d5dc1059ed8,
        0x629a292a367cd507,
        0x9159015a3070dd17,
        0x152fecd8f70e5939,
        0x67332667ffc00b31,
        0x8eb44a8768581511,
        0xdb0c2e0d64f98fa7,
        0x47b5481dbefa4fa4,
    ];
    sha512_pad_and_run(input, &mut state);

    let mut out = [0u8; 48];
    let mut i = 0;
    while i < 6 {
        out.as_chunks_mut().0[i] = state[i].to_be_bytes();
        i += 1;
    }
    out
}

/// Compute SHA-512 digest.
/// # Examples
/// ```
/// use cthash::sha2_512;
/// const H: [u8; 64] = sha2_512(b"data");
/// ```
pub const fn sha2_512(input: &[u8]) -> [u8; 64] {
    // SHA-512 IV
    let mut state = [
        0x6a09e667f3bcc908,
        0xbb67ae8584caa73b,
        0x3c6ef372fe94f82b,
        0xa54ff53a5f1d36f1,
        0x510e527fade682d1,
        0x9b05688c2b3e6c1f,
        0x1f83d9abfb41bd6b,
        0x5be0cd19137e2179,
    ];
    sha512_pad_and_run(input, &mut state);

    let mut out = [0u8; 64];
    let mut i = 0;
    while i < 8 {
        out.as_chunks_mut().0[i] = state[i].to_be_bytes();
        i += 1;
    }
    out
}

#[inline(always)]
const fn sha256_pad_and_run(input: &[u8], state: &mut [u32; 8]) {
    let mut b0 = [0; _];
    let mut b1 = [0; _];
    let bit_len = ((input.len() as u64) * 8).to_be_bytes();
    let (blocks, pad_two_blocks) = eager_split_pad(input, &bit_len, 0x80, &mut b0, &mut b1);

    let mut i = 0;
    while i < blocks.len() {
        sha256_compress(state, &blocks[i]);
        i += 1;
    }

    if pad_two_blocks {
        sha256_compress(state, &b0);
        sha256_compress(state, &b1);
    } else {
        sha256_compress(state, &b0);
    }
}

const K32: [u32; 64] = [
    0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be,
    0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa,
    0x5cb0a9dc, 0x76f988da, 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967, 0x27b70a85,
    0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
    0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f,
    0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2,
];

const fn sha256_compress(state: &mut [u32; 8], block: &[u8; 64]) {
    let mut w = [0u32; 64];
    let mut i = 0;

    let (w_words, _rem) = block.as_chunks();
    while i < 16 {
        w[i] = u32::from_be_bytes(w_words[i]);
        i += 1;
    }

    while i < 64 {
        let w15 = w[i - 15];
        let s0 = (w15.rotate_right(7)) ^ (w15.rotate_right(18)) ^ (w15 >> 3);
        let w2 = w[i - 2];
        let s1 = (w2.rotate_right(17)) ^ (w2.rotate_right(19)) ^ (w2 >> 10);

        w[i] = (w[i - 16]).wrapping_add(s0).wrapping_add(w[i - 7]).wrapping_add(s1);
        i += 1;
    }

    let mut state_cpy = *state;

    i = 0;
    while i < 64 {
        let [a, b, c, d, e, f, g, h] = state_cpy;

        let s1 = (e.rotate_right(6)) ^ (e.rotate_right(11)) ^ (e.rotate_right(25));
        let ch = (e & f) ^ ((!e) & g);
        let t1 = h.wrapping_add(s1).wrapping_add(ch).wrapping_add(K32[i]).wrapping_add(w[i]);
        let s0 = (a.rotate_right(2)) ^ (a.rotate_right(13)) ^ (a.rotate_right(22));
        let maj = (a & b) ^ (a & c) ^ (b & c);
        let t2 = s0.wrapping_add(maj);

        state_cpy = [t1.wrapping_add(t2), a, b, c, d.wrapping_add(t1), e, f, g];

        i += 1;
    }

    let [n_a, n_b, n_c, n_d, n_e, n_f, n_g, n_h] = state_cpy;

    state[0] = state[0].wrapping_add(n_a);
    state[1] = state[1].wrapping_add(n_b);
    state[2] = state[2].wrapping_add(n_c);
    state[3] = state[3].wrapping_add(n_d);
    state[4] = state[4].wrapping_add(n_e);
    state[5] = state[5].wrapping_add(n_f);
    state[6] = state[6].wrapping_add(n_g);
    state[7] = state[7].wrapping_add(n_h);
}

#[inline(always)]
const fn sha512_pad_and_run(input: &[u8], state: &mut [u64; 8]) {
    let mut b0 = [0; _];
    let mut b1 = [0; _];
    let bit_len = ((input.len() as u128) * 8).to_be_bytes();
    let (blocks, pad_two_blocks) = eager_split_pad(input, &bit_len, 0x80, &mut b0, &mut b1);

    let mut i = 0;
    while i < blocks.len() {
        sha512_compress(state, &blocks[i]);
        i += 1;
    }

    if pad_two_blocks {
        sha512_compress(state, &b0);
        sha512_compress(state, &b1);
    } else {
        sha512_compress(state, &b0);
    }
}

const K64: [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,
];

const fn sha512_compress(state: &mut [u64; 8], block: &[u8; 128]) {
    let mut w = [0u64; 80];
    let mut i = 0;

    let (w_words, _rem) = block.as_chunks();
    while i < 16 {
        w[i] = u64::from_be_bytes(w_words[i]);
        i += 1;
    }

    while i < 80 {
        let w15 = w[i - 15];
        let s0 = (w15.rotate_right(1)) ^ (w15.rotate_right(8)) ^ (w15 >> 7);
        let w2 = w[i - 2];
        let s1 = (w2.rotate_right(19)) ^ (w2.rotate_right(61)) ^ (w2 >> 6);
        w[i] = w[i - 16].wrapping_add(s0).wrapping_add(w[i - 7]).wrapping_add(s1);

        i += 1;
    }

    let mut state_cpy = *state;

    i = 0;
    while i < 80 {
        let [a, b, c, d, e, f, g, h] = state_cpy;

        let s1 = e.rotate_right(14) ^ e.rotate_right(18) ^ e.rotate_right(41);
        let ch = (e & f) ^ ((!e) & g);
        let t1 = s1.wrapping_add(ch).wrapping_add(K64[i]).wrapping_add(w[i]).wrapping_add(h);
        let s0 = a.rotate_right(28) ^ a.rotate_right(34) ^ a.rotate_right(39);
        let maj = (a & b) ^ (a & c) ^ (b & c);
        let t2 = s0.wrapping_add(maj);

        state_cpy = [t1.wrapping_add(t2), a, b, c, d.wrapping_add(t1), e, f, g];

        i += 1;
    }

    let [n_a, n_b, n_c, n_d, n_e, n_f, n_g, n_h] = state_cpy;

    state[0] = state[0].wrapping_add(n_a);
    state[1] = state[1].wrapping_add(n_b);
    state[2] = state[2].wrapping_add(n_c);
    state[3] = state[3].wrapping_add(n_d);
    state[4] = state[4].wrapping_add(n_e);
    state[5] = state[5].wrapping_add(n_f);
    state[6] = state[6].wrapping_add(n_g);
    state[7] = state[7].wrapping_add(n_h);
}