/* LibTomCrypt, modular cryptographic library -- Tom St Denis
 *
 * LibTomCrypt is a library that provides various cryptographic
 * algorithms in a highly modular and flexible manner.
 *
 * The library is free for all purposes without any express
 * guarantee it works.
 *
 * Tom St Denis, tomstdenis@gmail.com, http://libtom.org
 */

#include "sha512.h"

/* the K array */
static const uint64_t K[80] = {
    UINT64_C(0x428a2f98d728ae22), UINT64_C(0x7137449123ef65cd),
    UINT64_C(0xb5c0fbcfec4d3b2f), UINT64_C(0xe9b5dba58189dbbc),
    UINT64_C(0x3956c25bf348b538), UINT64_C(0x59f111f1b605d019),
    UINT64_C(0x923f82a4af194f9b), UINT64_C(0xab1c5ed5da6d8118),
    UINT64_C(0xd807aa98a3030242), UINT64_C(0x12835b0145706fbe),
    UINT64_C(0x243185be4ee4b28c), UINT64_C(0x550c7dc3d5ffb4e2),
    UINT64_C(0x72be5d74f27b896f), UINT64_C(0x80deb1fe3b1696b1),
    UINT64_C(0x9bdc06a725c71235), UINT64_C(0xc19bf174cf692694),
    UINT64_C(0xe49b69c19ef14ad2), UINT64_C(0xefbe4786384f25e3),
    UINT64_C(0x0fc19dc68b8cd5b5), UINT64_C(0x240ca1cc77ac9c65),
    UINT64_C(0x2de92c6f592b0275), UINT64_C(0x4a7484aa6ea6e483),
    UINT64_C(0x5cb0a9dcbd41fbd4), UINT64_C(0x76f988da831153b5),
    UINT64_C(0x983e5152ee66dfab), UINT64_C(0xa831c66d2db43210),
    UINT64_C(0xb00327c898fb213f), UINT64_C(0xbf597fc7beef0ee4),
    UINT64_C(0xc6e00bf33da88fc2), UINT64_C(0xd5a79147930aa725),
    UINT64_C(0x06ca6351e003826f), UINT64_C(0x142929670a0e6e70),
    UINT64_C(0x27b70a8546d22ffc), UINT64_C(0x2e1b21385c26c926),
    UINT64_C(0x4d2c6dfc5ac42aed), UINT64_C(0x53380d139d95b3df),
    UINT64_C(0x650a73548baf63de), UINT64_C(0x766a0abb3c77b2a8),
    UINT64_C(0x81c2c92e47edaee6), UINT64_C(0x92722c851482353b),
    UINT64_C(0xa2bfe8a14cf10364), UINT64_C(0xa81a664bbc423001),
    UINT64_C(0xc24b8b70d0f89791), UINT64_C(0xc76c51a30654be30),
    UINT64_C(0xd192e819d6ef5218), UINT64_C(0xd69906245565a910),
    UINT64_C(0xf40e35855771202a), UINT64_C(0x106aa07032bbd1b8),
    UINT64_C(0x19a4c116b8d2d0c8), UINT64_C(0x1e376c085141ab53),
    UINT64_C(0x2748774cdf8eeb99), UINT64_C(0x34b0bcb5e19b48a8),
    UINT64_C(0x391c0cb3c5c95a63), UINT64_C(0x4ed8aa4ae3418acb),
    UINT64_C(0x5b9cca4f7763e373), UINT64_C(0x682e6ff3d6b2b8a3),
    UINT64_C(0x748f82ee5defb2fc), UINT64_C(0x78a5636f43172f60),
    UINT64_C(0x84c87814a1f0ab72), UINT64_C(0x8cc702081a6439ec),
    UINT64_C(0x90befffa23631e28), UINT64_C(0xa4506cebde82bde9),
    UINT64_C(0xbef9a3f7b2c67915), UINT64_C(0xc67178f2e372532b),
    UINT64_C(0xca273eceea26619c), UINT64_C(0xd186b8c721c0c207),
    UINT64_C(0xeada7dd6cde0eb1e), UINT64_C(0xf57d4f7fee6ed178),
    UINT64_C(0x06f067aa72176fba), UINT64_C(0x0a637dc5a2c898a6),
    UINT64_C(0x113f9804bef90dae), UINT64_C(0x1b710b35131c471b),
    UINT64_C(0x28db77f523047d84), UINT64_C(0x32caab7b40c72493),
    UINT64_C(0x3c9ebe0a15c9bebc), UINT64_C(0x431d67c49c100d4c),
    UINT64_C(0x4cc5d4becb3e42b6), UINT64_C(0x597f299cfc657e2a),
    UINT64_C(0x5fcb6fab3ad6faec), UINT64_C(0x6c44198c4a475817)};

/* Various logical functions */

#define ROR64c(x, y)                                                             \
    (((((x) & UINT64_C(0xFFFFFFFFFFFFFFFF)) >> ((uint64_t)(y) & UINT64_C(63))) | \
      ((x) << ((uint64_t)(64 - ((y) & UINT64_C(63)))))) &                        \
     UINT64_C(0xFFFFFFFFFFFFFFFF))

#define STORE64H(x, y)                               \
    {                                                \
        (y)[0] = (unsigned char)(((x) >> 56) & 255); \
        (y)[1] = (unsigned char)(((x) >> 48) & 255); \
        (y)[2] = (unsigned char)(((x) >> 40) & 255); \
        (y)[3] = (unsigned char)(((x) >> 32) & 255); \
        (y)[4] = (unsigned char)(((x) >> 24) & 255); \
        (y)[5] = (unsigned char)(((x) >> 16) & 255); \
        (y)[6] = (unsigned char)(((x) >> 8) & 255);  \
        (y)[7] = (unsigned char)((x) & 255);         \
    }

#define LOAD64H(x, y)                                                                 \
    {                                                                                 \
        x = (((uint64_t)((y)[0] & 255)) << 56) | (((uint64_t)((y)[1] & 255)) << 48) | \
            (((uint64_t)((y)[2] & 255)) << 40) | (((uint64_t)((y)[3] & 255)) << 32) | \
            (((uint64_t)((y)[4] & 255)) << 24) | (((uint64_t)((y)[5] & 255)) << 16) | \
            (((uint64_t)((y)[6] & 255)) << 8) | (((uint64_t)((y)[7] & 255)));         \
    }

#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) & UINT64_C(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))
#ifndef MIN
#define MIN(x, y) (((x) < (y)) ? (x) : (y))
#endif

/* compress 1024-bits */
static int sha512_compress(sha512_context *md, unsigned char *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);
    }

#undef RND

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

    return 0;
}

/**
   Initialize the hash state
   @param md   The hash state you wish to initialize
   @return 0 if successful
*/
int sha512_init(sha512_context *md)
{
    if (md == NULL)
        return 1;

    md->curlen = 0;
    md->length = 0;
    md->state[0] = UINT64_C(0x6a09e667f3bcc908);
    md->state[1] = UINT64_C(0xbb67ae8584caa73b);
    md->state[2] = UINT64_C(0x3c6ef372fe94f82b);
    md->state[3] = UINT64_C(0xa54ff53a5f1d36f1);
    md->state[4] = UINT64_C(0x510e527fade682d1);
    md->state[5] = UINT64_C(0x9b05688c2b3e6c1f);
    md->state[6] = UINT64_C(0x1f83d9abfb41bd6b);
    md->state[7] = UINT64_C(0x5be0cd19137e2179);

    return 0;
}

/**
   Process a block of memory though the hash
   @param md     The hash state
   @param in     The data to hash
   @param inlen  The length of the data (octets)
   @return 0 if successful
*/
int sha512_update(sha512_context *md, const unsigned char *in, unsigned int inlen)
{
    unsigned int n;
    unsigned int i;
    int err;
    if (md == NULL)
        return 1;
    if (in == NULL)
        return 1;
    if (md->curlen > sizeof(md->buf))
    {
        return 1;
    }
    while (inlen > 0)
    {
        if (md->curlen == 0 && inlen >= 128)
        {
            if ((err = sha512_compress(md, (unsigned char *)in)) != 0)
            {
                return err;
            }
            md->length += 128 * 8;
            in += 128;
            inlen -= 128;
        }
        else
        {
            n = MIN(inlen, (128 - md->curlen));

            for (i = 0; i < n; i++)
            {
                md->buf[i + md->curlen] = in[i];
            }

            md->curlen += n;
            in += n;
            inlen -= n;
            if (md->curlen == 128)
            {
                if ((err = sha512_compress(md, md->buf)) != 0)
                {
                    return err;
                }
                md->length += 8 * 128;
                md->curlen = 0;
            }
        }
    }
    return 0;
}

/**
   Terminate the hash to get the digest
   @param md  The hash state
   @param out [out] The destination of the hash (64 bytes)
   @return 0 if successful
*/
int sha512_final(sha512_context *md, unsigned char *out)
{
    int i;

    if (md == NULL)
        return 1;
    if (out == NULL)
        return 1;

    if (md->curlen >= sizeof(md->buf))
    {
        return 1;
    }

    /* increase the length of the message */
    md->length += md->curlen * UINT64_C(8);

    /* append the '1' bit */
    md->buf[md->curlen++] = (unsigned char)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++] = (unsigned char)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++] = (unsigned char)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));
    }

    return 0;
}

int sha512(const unsigned char *message, unsigned int message_len, unsigned char *out)
{
    sha512_context ctx;
    int ret;
    if ((ret = sha512_init(&ctx)))
        return ret;
    if ((ret = sha512_update(&ctx, message, message_len)))
        return ret;
    if ((ret = sha512_final(&ctx, out)))
        return ret;
    return 0;
}
