/* Based on the public domain implementation in
 * crypto_hash/sha512/ref/ from http://bench.cr.yp.to/supercop.html
 * by D. J. Bernstein */

#include <stddef.h>
#include <stdint.h>

#include "sha2.h"

static uint64_t load_bigendian(const unsigned char *x) {
    return (uint64_t)(x[7]) | (((uint64_t)(x[6])) << 8) | (((uint64_t)(x[5])) << 16) |
           (((uint64_t)(x[4])) << 24) | (((uint64_t)(x[3])) << 32) |
           (((uint64_t)(x[2])) << 40) | (((uint64_t)(x[1])) << 48) |
           (((uint64_t)(x[0])) << 56);
}

static void store_bigendian(uint8_t *x, uint64_t u) {
    x[7] = (uint8_t) u;
    u >>= 8;
    x[6] = (uint8_t) u;
    u >>= 8;
    x[5] = (uint8_t) u;
    u >>= 8;
    x[4] = (uint8_t) u;
    u >>= 8;
    x[3] = (uint8_t) u;
    u >>= 8;
    x[2] = (uint8_t) u;
    u >>= 8;
    x[1] = (uint8_t) u;
    u >>= 8;
    x[0] = (uint8_t) u;
}

#define SHR(x, c) ((x) >> (c))
#define ROTR(x, c) (((x) >> (c)) | ((x) << (64 - (c))))

#define Ch(x, y, z) (((x) & (y)) ^ (~(x) & (z)))
#define Maj(x, y, z) (((x) & (y)) ^ ((x) & (z)) ^ ((y) & (z)))
#define Sigma0(x) (ROTR(x, 28) ^ ROTR(x, 34) ^ ROTR(x, 39))
#define Sigma1(x) (ROTR(x, 14) ^ ROTR(x, 18) ^ ROTR(x, 41))
#define sigma0(x) (ROTR(x, 1) ^ ROTR(x, 8) ^ SHR(x, 7))
#define sigma1(x) (ROTR(x, 19) ^ ROTR(x, 61) ^ SHR(x, 6))

#define M(w0, w14, w9, w1) w0 = sigma1(w14) + (w9) + sigma0(w1) + (w0);

#define EXPAND           \
    M(w0, w14, w9, w1)   \
    M(w1, w15, w10, w2)  \
    M(w2, w0, w11, w3)   \
    M(w3, w1, w12, w4)   \
    M(w4, w2, w13, w5)   \
    M(w5, w3, w14, w6)   \
    M(w6, w4, w15, w7)   \
    M(w7, w5, w0, w8)    \
    M(w8, w6, w1, w9)    \
    M(w9, w7, w2, w10)   \
    M(w10, w8, w3, w11)  \
    M(w11, w9, w4, w12)  \
    M(w12, w10, w5, w13) \
    M(w13, w11, w6, w14) \
    M(w14, w12, w7, w15) \
    M(w15, w13, w8, w0)

#define F(w, k)                                   \
    T1 = h + Sigma1(e) + Ch(e, f, g) + (k) + (w); \
    T2 = Sigma0(a) + Maj(a, b, c);                \
    h = g;                                        \
    g = f;                                        \
    f = e;                                        \
    e = d + T1;                                   \
    d = c;                                        \
    c = b;                                        \
    b = a;                                        \
    a = T1 + T2;

static size_t crypto_hashblocks_sha512(uint8_t *statebytes,
                                       const uint8_t *in,
                                       size_t inlen) {
    uint64_t state[8];
    uint64_t a;
    uint64_t b;
    uint64_t c;
    uint64_t d;
    uint64_t e;
    uint64_t f;
    uint64_t g;
    uint64_t h;
    uint64_t T1;
    uint64_t T2;

    a = load_bigendian(statebytes + 0);
    state[0] = a;
    b = load_bigendian(statebytes + 8);
    state[1] = b;
    c = load_bigendian(statebytes + 16);
    state[2] = c;
    d = load_bigendian(statebytes + 24);
    state[3] = d;
    e = load_bigendian(statebytes + 32);
    state[4] = e;
    f = load_bigendian(statebytes + 40);
    state[5] = f;
    g = load_bigendian(statebytes + 48);
    state[6] = g;
    h = load_bigendian(statebytes + 56);
    state[7] = h;

    while (inlen >= 128) {
        uint64_t w0 = load_bigendian(in + 0);
        uint64_t w1 = load_bigendian(in + 8);
        uint64_t w2 = load_bigendian(in + 16);
        uint64_t w3 = load_bigendian(in + 24);
        uint64_t w4 = load_bigendian(in + 32);
        uint64_t w5 = load_bigendian(in + 40);
        uint64_t w6 = load_bigendian(in + 48);
        uint64_t w7 = load_bigendian(in + 56);
        uint64_t w8 = load_bigendian(in + 64);
        uint64_t w9 = load_bigendian(in + 72);
        uint64_t w10 = load_bigendian(in + 80);
        uint64_t w11 = load_bigendian(in + 88);
        uint64_t w12 = load_bigendian(in + 96);
        uint64_t w13 = load_bigendian(in + 104);
        uint64_t w14 = load_bigendian(in + 112);
        uint64_t w15 = load_bigendian(in + 120);

        F(w0, 0x428a2f98d728ae22ULL)
        F(w1, 0x7137449123ef65cdULL)
        F(w2, 0xb5c0fbcfec4d3b2fULL)
        F(w3, 0xe9b5dba58189dbbcULL)
        F(w4, 0x3956c25bf348b538ULL)
        F(w5, 0x59f111f1b605d019ULL)
        F(w6, 0x923f82a4af194f9bULL)
        F(w7, 0xab1c5ed5da6d8118ULL)
        F(w8, 0xd807aa98a3030242ULL)
        F(w9, 0x12835b0145706fbeULL)
        F(w10, 0x243185be4ee4b28cULL)
        F(w11, 0x550c7dc3d5ffb4e2ULL)
        F(w12, 0x72be5d74f27b896fULL)
        F(w13, 0x80deb1fe3b1696b1ULL)
        F(w14, 0x9bdc06a725c71235ULL)
        F(w15, 0xc19bf174cf692694ULL)

        EXPAND

        F(w0, 0xe49b69c19ef14ad2ULL)
        F(w1, 0xefbe4786384f25e3ULL)
        F(w2, 0x0fc19dc68b8cd5b5ULL)
        F(w3, 0x240ca1cc77ac9c65ULL)
        F(w4, 0x2de92c6f592b0275ULL)
        F(w5, 0x4a7484aa6ea6e483ULL)
        F(w6, 0x5cb0a9dcbd41fbd4ULL)
        F(w7, 0x76f988da831153b5ULL)
        F(w8, 0x983e5152ee66dfabULL)
        F(w9, 0xa831c66d2db43210ULL)
        F(w10, 0xb00327c898fb213fULL)
        F(w11, 0xbf597fc7beef0ee4ULL)
        F(w12, 0xc6e00bf33da88fc2ULL)
        F(w13, 0xd5a79147930aa725ULL)
        F(w14, 0x06ca6351e003826fULL)
        F(w15, 0x142929670a0e6e70ULL)

        EXPAND

        F(w0, 0x27b70a8546d22ffcULL)
        F(w1, 0x2e1b21385c26c926ULL)
        F(w2, 0x4d2c6dfc5ac42aedULL)
        F(w3, 0x53380d139d95b3dfULL)
        F(w4, 0x650a73548baf63deULL)
        F(w5, 0x766a0abb3c77b2a8ULL)
        F(w6, 0x81c2c92e47edaee6ULL)
        F(w7, 0x92722c851482353bULL)
        F(w8, 0xa2bfe8a14cf10364ULL)
        F(w9, 0xa81a664bbc423001ULL)
        F(w10, 0xc24b8b70d0f89791ULL)
        F(w11, 0xc76c51a30654be30ULL)
        F(w12, 0xd192e819d6ef5218ULL)
        F(w13, 0xd69906245565a910ULL)
        F(w14, 0xf40e35855771202aULL)
        F(w15, 0x106aa07032bbd1b8ULL)

        EXPAND

        F(w0, 0x19a4c116b8d2d0c8ULL)
        F(w1, 0x1e376c085141ab53ULL)
        F(w2, 0x2748774cdf8eeb99ULL)
        F(w3, 0x34b0bcb5e19b48a8ULL)
        F(w4, 0x391c0cb3c5c95a63ULL)
        F(w5, 0x4ed8aa4ae3418acbULL)
        F(w6, 0x5b9cca4f7763e373ULL)
        F(w7, 0x682e6ff3d6b2b8a3ULL)
        F(w8, 0x748f82ee5defb2fcULL)
        F(w9, 0x78a5636f43172f60ULL)
        F(w10, 0x84c87814a1f0ab72ULL)
        F(w11, 0x8cc702081a6439ecULL)
        F(w12, 0x90befffa23631e28ULL)
        F(w13, 0xa4506cebde82bde9ULL)
        F(w14, 0xbef9a3f7b2c67915ULL)
        F(w15, 0xc67178f2e372532bULL)

        EXPAND

        F(w0, 0xca273eceea26619cULL)
        F(w1, 0xd186b8c721c0c207ULL)
        F(w2, 0xeada7dd6cde0eb1eULL)
        F(w3, 0xf57d4f7fee6ed178ULL)
        F(w4, 0x06f067aa72176fbaULL)
        F(w5, 0x0a637dc5a2c898a6ULL)
        F(w6, 0x113f9804bef90daeULL)
        F(w7, 0x1b710b35131c471bULL)
        F(w8, 0x28db77f523047d84ULL)
        F(w9, 0x32caab7b40c72493ULL)
        F(w10, 0x3c9ebe0a15c9bebcULL)
        F(w11, 0x431d67c49c100d4cULL)
        F(w12, 0x4cc5d4becb3e42b6ULL)
        F(w13, 0x597f299cfc657e2aULL)
        F(w14, 0x5fcb6fab3ad6faecULL)
        F(w15, 0x6c44198c4a475817ULL)

        a += state[0];
        b += state[1];
        c += state[2];
        d += state[3];
        e += state[4];
        f += state[5];
        g += state[6];
        h += state[7];

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

        in += 128;
        inlen -= 128;
    }

    store_bigendian(statebytes + 0, state[0]);
    store_bigendian(statebytes + 8, state[1]);
    store_bigendian(statebytes + 16, state[2]);
    store_bigendian(statebytes + 24, state[3]);
    store_bigendian(statebytes + 32, state[4]);
    store_bigendian(statebytes + 40, state[5]);
    store_bigendian(statebytes + 48, state[6]);
    store_bigendian(statebytes + 56, state[7]);

    return inlen;
}

#define blocks crypto_hashblocks_sha512

static const uint8_t iv_384[64] = {
    0xcb, 0xbb, 0x9d, 0x5d, 0xc1, 0x05, 0x9e, 0xd8, 0x62, 0x9a, 0x29,
    0x2a, 0x36, 0x7c, 0xd5, 0x07, 0x91, 0x59, 0x01, 0x5a, 0x30, 0x70,
    0xdd, 0x17, 0x15, 0x2f, 0xec, 0xd8, 0xf7, 0x0e, 0x59, 0x39, 0x67,
    0x33, 0x26, 0x67, 0xff, 0xc0, 0x0b, 0x31, 0x8e, 0xb4, 0x4a, 0x87,
    0x68, 0x58, 0x15, 0x11, 0xdb, 0x0c, 0x2e, 0x0d, 0x64, 0xf9, 0x8f,
    0xa7, 0x47, 0xb5, 0x48, 0x1d, 0xbe, 0xfa, 0x4f, 0xa4
};

static const uint8_t iv_512[64] = {
    0x6a, 0x09, 0xe6, 0x67, 0xf3, 0xbc, 0xc9, 0x08, 0xbb, 0x67, 0xae,
    0x85, 0x84, 0xca, 0xa7, 0x3b, 0x3c, 0x6e, 0xf3, 0x72, 0xfe, 0x94,
    0xf8, 0x2b, 0xa5, 0x4f, 0xf5, 0x3a, 0x5f, 0x1d, 0x36, 0xf1, 0x51,
    0x0e, 0x52, 0x7f, 0xad, 0xe6, 0x82, 0xd1, 0x9b, 0x05, 0x68, 0x8c,
    0x2b, 0x3e, 0x6c, 0x1f, 0x1f, 0x83, 0xd9, 0xab, 0xfb, 0x41, 0xbd,
    0x6b, 0x5b, 0xe0, 0xcd, 0x19, 0x13, 0x7e, 0x21, 0x79
};

int sha384(uint8_t *out, const uint8_t *in, size_t inlen) {
    uint8_t h[64];
    uint8_t padded[256];
    uint64_t bytes = inlen;

    for (size_t i = 0; i < 64; ++i) {
        h[i] = iv_384[i];
    }

    blocks(h, in, inlen);
    in += inlen;
    inlen &= 127;
    in -= inlen;

    for (size_t i = 0; i < inlen; ++i) {
        padded[i] = in[i];
    }
    padded[inlen] = 0x80;

    if (inlen < 112) {
        for (size_t i = inlen + 1; i < 119; ++i) {
            padded[i] = 0;
        }
        padded[119] = (uint8_t) (bytes >> 61);
        padded[120] = (uint8_t) (bytes >> 53);
        padded[121] = (uint8_t) (bytes >> 45);
        padded[122] = (uint8_t) (bytes >> 37);
        padded[123] = (uint8_t) (bytes >> 29);
        padded[124] = (uint8_t) (bytes >> 21);
        padded[125] = (uint8_t) (bytes >> 13);
        padded[126] = (uint8_t) (bytes >> 5);
        padded[127] = (uint8_t) (bytes << 3);
        blocks(h, padded, 128);
    } else {
        for (size_t i = inlen + 1; i < 247; ++i) {
            padded[i] = 0;
        }
        padded[247] = (uint8_t) (bytes >> 61);
        padded[248] = (uint8_t) (bytes >> 53);
        padded[249] = (uint8_t) (bytes >> 45);
        padded[250] = (uint8_t) (bytes >> 37);
        padded[251] = (uint8_t) (bytes >> 29);
        padded[252] = (uint8_t) (bytes >> 21);
        padded[253] = (uint8_t) (bytes >> 13);
        padded[254] = (uint8_t) (bytes >> 5);
        padded[255] = (uint8_t) (bytes << 3);
        blocks(h, padded, 256);
    }

    for (size_t i = 0; i < 48; ++i) {
        out[i] = h[i];
    }

    return 0;
}

int sha512(uint8_t *out, const uint8_t *in, size_t inlen) {
    uint8_t h[64];
    uint8_t padded[256];
    uint64_t bytes = inlen;

    for (size_t i = 0; i < 64; ++i) {
        h[i] = iv_512[i];
    }

    blocks(h, in, inlen);
    in += inlen;
    inlen &= 127;
    in -= inlen;

    for (size_t i = 0; i < inlen; ++i) {
        padded[i] = in[i];
    }
    padded[inlen] = 0x80;

    if (inlen < 112) {
        for (size_t i = inlen + 1; i < 119; ++i) {
            padded[i] = 0;
        }
        padded[119] = (uint8_t) (bytes >> 61);
        padded[120] = (uint8_t) (bytes >> 53);
        padded[121] = (uint8_t) (bytes >> 45);
        padded[122] = (uint8_t) (bytes >> 37);
        padded[123] = (uint8_t) (bytes >> 29);
        padded[124] = (uint8_t) (bytes >> 21);
        padded[125] = (uint8_t) (bytes >> 13);
        padded[126] = (uint8_t) (bytes >> 5);
        padded[127] = (uint8_t) (bytes << 3);
        blocks(h, padded, 128);
    } else {
        for (size_t i = inlen + 1; i < 247; ++i) {
            padded[i] = 0;
        }
        padded[247] = (uint8_t) (bytes >> 61);
        padded[248] = (uint8_t) (bytes >> 53);
        padded[249] = (uint8_t) (bytes >> 45);
        padded[250] = (uint8_t) (bytes >> 37);
        padded[251] = (uint8_t) (bytes >> 29);
        padded[252] = (uint8_t) (bytes >> 21);
        padded[253] = (uint8_t) (bytes >> 13);
        padded[254] = (uint8_t) (bytes >> 5);
        padded[255] = (uint8_t) (bytes << 3);
        blocks(h, padded, 256);
    }

    for (size_t i = 0; i < 64; ++i) {
        out[i] = h[i];
    }

    return 0;
}