/*
 * Code originally from LibTomCrypt -- Licensed under the Public Domain/WTFPL2.0
 */

#include "sha512.h"
#include "sha.h"

/* the K array */
static const uint64_t K[80] = {
    CONST64(0x428a2f98d728ae22), CONST64(0x7137449123ef65cd),
    CONST64(0xb5c0fbcfec4d3b2f), CONST64(0xe9b5dba58189dbbc),
    CONST64(0x3956c25bf348b538), CONST64(0x59f111f1b605d019),
    CONST64(0x923f82a4af194f9b), CONST64(0xab1c5ed5da6d8118),
    CONST64(0xd807aa98a3030242), CONST64(0x12835b0145706fbe),
    CONST64(0x243185be4ee4b28c), CONST64(0x550c7dc3d5ffb4e2),
    CONST64(0x72be5d74f27b896f), CONST64(0x80deb1fe3b1696b1),
    CONST64(0x9bdc06a725c71235), CONST64(0xc19bf174cf692694),
    CONST64(0xe49b69c19ef14ad2), CONST64(0xefbe4786384f25e3),
    CONST64(0x0fc19dc68b8cd5b5), CONST64(0x240ca1cc77ac9c65),
    CONST64(0x2de92c6f592b0275), CONST64(0x4a7484aa6ea6e483),
    CONST64(0x5cb0a9dcbd41fbd4), CONST64(0x76f988da831153b5),
    CONST64(0x983e5152ee66dfab), CONST64(0xa831c66d2db43210),
    CONST64(0xb00327c898fb213f), CONST64(0xbf597fc7beef0ee4),
    CONST64(0xc6e00bf33da88fc2), CONST64(0xd5a79147930aa725),
    CONST64(0x06ca6351e003826f), CONST64(0x142929670a0e6e70),
    CONST64(0x27b70a8546d22ffc), CONST64(0x2e1b21385c26c926),
    CONST64(0x4d2c6dfc5ac42aed), CONST64(0x53380d139d95b3df),
    CONST64(0x650a73548baf63de), CONST64(0x766a0abb3c77b2a8),
    CONST64(0x81c2c92e47edaee6), CONST64(0x92722c851482353b),
    CONST64(0xa2bfe8a14cf10364), CONST64(0xa81a664bbc423001),
    CONST64(0xc24b8b70d0f89791), CONST64(0xc76c51a30654be30),
    CONST64(0xd192e819d6ef5218), CONST64(0xd69906245565a910),
    CONST64(0xf40e35855771202a), CONST64(0x106aa07032bbd1b8),
    CONST64(0x19a4c116b8d2d0c8), CONST64(0x1e376c085141ab53),
    CONST64(0x2748774cdf8eeb99), CONST64(0x34b0bcb5e19b48a8),
    CONST64(0x391c0cb3c5c95a63), CONST64(0x4ed8aa4ae3418acb),
    CONST64(0x5b9cca4f7763e373), CONST64(0x682e6ff3d6b2b8a3),
    CONST64(0x748f82ee5defb2fc), CONST64(0x78a5636f43172f60),
    CONST64(0x84c87814a1f0ab72), CONST64(0x8cc702081a6439ec),
    CONST64(0x90befffa23631e28), CONST64(0xa4506cebde82bde9),
    CONST64(0xbef9a3f7b2c67915), CONST64(0xc67178f2e372532b),
    CONST64(0xca273eceea26619c), CONST64(0xd186b8c721c0c207),
    CONST64(0xeada7dd6cde0eb1e), CONST64(0xf57d4f7fee6ed178),
    CONST64(0x06f067aa72176fba), CONST64(0x0a637dc5a2c898a6),
    CONST64(0x113f9804bef90dae), CONST64(0x1b710b35131c471b),
    CONST64(0x28db77f523047d84), CONST64(0x32caab7b40c72493),
    CONST64(0x3c9ebe0a15c9bebc), CONST64(0x431d67c49c100d4c),
    CONST64(0x4cc5d4becb3e42b6), CONST64(0x597f299cfc657e2a),
    CONST64(0x5fcb6fab3ad6faec), CONST64(0x6c44198c4a475817)};

/* Various logical functions */
#define Ch(x, y, z) (z ^ (x & (y ^ z)))
#define Maj(x, y, z) (((x | y) & z) | (x & y))
#define S(x, n) ROR64c(x, n)
#define R(x, n) (((x)&CONST64(0xFFFFFFFFFFFFFFFF)) >> ((uint64_t)n))
#define Sigma0(x) (S(x, 28) ^ S(x, 34) ^ S(x, 39))
#define Sigma1(x) (S(x, 14) ^ S(x, 18) ^ S(x, 41))
#define Gamma0(x) (S(x, 1) ^ S(x, 8) ^ R(x, 7))
#define Gamma1(x) (S(x, 19) ^ S(x, 61) ^ R(x, 6))

/* compress 1024-bits */
static void sha512_compress(sha512_context *md, const uint8_t *buf)
{
    uint64_t S[8], W[80], t0, t1;
    int i;

    /* copy state into S */
    for (i = 0; i < 8; i++) {
        S[i] = md->state[i];
    }

    /* copy the state into 1024-bits into W[0..15] */
    for (i = 0; i < 16; i++) {
        LOAD64H(W[i], buf + (8 * i));
    }

    /* fill W[16..79] */
    for (i = 16; i < 80; i++) {
        W[i] = Gamma1(W[i - 2]) + W[i - 7] + Gamma0(W[i - 15]) + W[i - 16];
    }

    /* Compress */
#define RND(a, b, c, d, e, f, g, h, i)              \
    t0 = h + Sigma1(e) + Ch(e, f, g) + K[i] + W[i]; \
    t1 = Sigma0(a) + Maj(a, b, c);                  \
    d += t0;                                        \
    h = t0 + t1;

    for (i = 0; i < 80; i += 8) {
        RND(S[0], S[1], S[2], S[3], S[4], S[5], S[6], S[7], i + 0);
        RND(S[7], S[0], S[1], S[2], S[3], S[4], S[5], S[6], i + 1);
        RND(S[6], S[7], S[0], S[1], S[2], S[3], S[4], S[5], i + 2);
        RND(S[5], S[6], S[7], S[0], S[1], S[2], S[3], S[4], i + 3);
        RND(S[4], S[5], S[6], S[7], S[0], S[1], S[2], S[3], i + 4);
        RND(S[3], S[4], S[5], S[6], S[7], S[0], S[1], S[2], i + 5);
        RND(S[2], S[3], S[4], S[5], S[6], S[7], S[0], S[1], i + 6);
        RND(S[1], S[2], S[3], S[4], S[5], S[6], S[7], S[0], i + 7);
    }

    /* feedback */
    for (i = 0; i < 8; i++) {
        md->state[i] = md->state[i] + S[i];
    }
}

void sha512_init(sha512_context *md)
{
    md->curlen = 0;
    md->length = 0;
    md->state[0] = CONST64(0x6a09e667f3bcc908);
    md->state[1] = CONST64(0xbb67ae8584caa73b);
    md->state[2] = CONST64(0x3c6ef372fe94f82b);
    md->state[3] = CONST64(0xa54ff53a5f1d36f1);
    md->state[4] = CONST64(0x510e527fade682d1);
    md->state[5] = CONST64(0x9b05688c2b3e6c1f);
    md->state[6] = CONST64(0x1f83d9abfb41bd6b);
    md->state[7] = CONST64(0x5be0cd19137e2179);
}

void sha512_process(sha512_context *md, const uint8_t *in, size_t inlen)
{
    size_t n;
    if (md->curlen > sizeof(md->buf)) {
        return;
    }
    if ((md->length + inlen) < md->length) {
        return;
    }
    while (inlen > 0) {
        if (md->curlen == 0 && inlen >= 128) {
            sha512_compress(md, in);
            md->length += 128 * 8;
            in += 128;
            inlen -= 128;
        } else {
            n = (((inlen) < ((128u - md->curlen))) ? (inlen)
                                                   : ((128u - md->curlen)));
            memcpy(md->buf + md->curlen, in, (size_t)n);
            md->curlen += n;
            in += n;
            inlen -= n;
            if (md->curlen == 128) {
                sha512_compress(md, md->buf);
                md->length += 8 * 128;
                md->curlen = 0;
            }
        }
    }
}

void sha512_done(sha512_context *md, uint8_t *out)
{
    int i;

    if (md->curlen >= sizeof(md->buf)) {
        return;
    }

    /* increase the length of the message */
    md->length += md->curlen * CONST64(8);

    /* append the '1' bit */
    md->buf[md->curlen++] = (uint8_t)0x80;

    /* if the length is currently above 112 bytes we append zeros
     * then compress.  Then we can fall back to padding zeros and length
     * encoding like normal.
     */
    if (md->curlen > 112) {
        while (md->curlen < 128) {
            md->buf[md->curlen++] = (uint8_t)0;
        }
        sha512_compress(md, md->buf);
        md->curlen = 0;
    }

    /* pad upto 120 bytes of zeroes
     * note: that from 112 to 120 is the 64 MSB of the length.  We assume that
     * you won't hash > 2^64 bits of data... :-)
     */
    while (md->curlen < 120) {
        md->buf[md->curlen++] = (uint8_t)0;
    }

    /* store length */
    STORE64H(md->length, md->buf + 120);
    sha512_compress(md, md->buf);

    /* copy output */
    for (i = 0; i < 8; i++) {
        STORE64H(md->state[i], out + (8 * i));
    }
}

void sha512_hash(const uint8_t *data, size_t len, uint8_t *digest)
{
    sha512_context md;
    sha512_init(&md);
    sha512_process(&md, data, len);
    sha512_done(&md, digest);
}