/* Taken from public domain libtomcrypt library and the code and all changes
   to it are in public domain. -Pekka */

/* LibTomCrypt, modular cryptographic library -- Tom St Denis */

#include "silc.h"
#include "sha512_internal.h"
#include "sha512.h"

/*
 * SILC Hash API for SHA512
 */

SILC_HASH_API_INIT(sha512)
{
  sha512_init(context);
}

SILC_HASH_API_UPDATE(sha512)
{
  sha512_process(context, (unsigned char *)data, len);
}

SILC_HASH_API_FINAL(sha512)
{
  sha512_done(context, digest);
}

SILC_HASH_API_TRANSFORM(sha512)
{
  sha512_transform(state, (unsigned char *)buffer);
}

SILC_HASH_API_CONTEXT_LEN(sha512)
{
  return sizeof(sha512_state);
}

#ifndef CONST64
#ifdef _MSC_VER
#define CONST64(n) n ## ui64
#else
#define CONST64(n) n ## ULL
#endif /* _MSC_VER */
#endif /* CONST64 */

static const ulong64 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)         silc_ror64(x, x)
#define R(x, n)         (((x)&CONST64(0xFFFFFFFFFFFFFFFF))>>((ulong64)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 */
void sha512_transform(SilcUInt64 *state, unsigned char *buf)
{
  ulong64 S[8], W[80], t0, t1;
  int i;

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

  /* copy the state into 1024-bits into W[0..15] */
  for (i = 0; i < 16; i++)
    SILC_GET64_MSB(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++) {
    state[i] = state[i] + S[i];
  }
}

int sha512_init(sha512_state * 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);
  return TRUE;
}

#if !defined(MIN)
#define MIN(x,y) ((x)<(y)?(x):(y))
#endif

int sha512_process(sha512_state * md, const unsigned char *in,
		   unsigned long inlen)
{
  unsigned long n;
  int block_size = sizeof(md->buf);

  if (md->curlen > block_size)
    return FALSE;

  while (inlen > 0) {
    if (md->curlen == 0 && inlen >= block_size) {
      sha512_transform(md->state, (unsigned char *)in);
      md->length += block_size * 8;
      in             += block_size;
      inlen          -= block_size;
    } else {
      n = MIN(inlen, (block_size - md->curlen));
      memcpy(md->buf + md->curlen, in, (size_t)n);
      md->curlen += n;
      in             += n;
      inlen          -= n;
      if (md->curlen == block_size) {
	sha512_transform(md->state, md->buf);
	md->length += block_size * 8;
	md->curlen = 0;
      }
    }
  }
  return TRUE;
}

int sha512_done(sha512_state * md, unsigned char *out)
{
  int i;

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

  /* increase the length of the message */
  md->length += md->curlen * CONST64(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_transform(md->state, 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 */
  SILC_PUT64_MSB(md->length, md->buf + 120);
  sha512_transform(md->state, md->buf);

  /* copy output */
  for (i = 0; i < 8; i += 2) {
    SILC_PUT64_MSB(md->state[i], out + (8 * i));
    SILC_PUT64_MSB(md->state[i + 1], out + (8 * (i + 1)));
  }

  return TRUE;
}