/*
   BLAKE2 reference source code package - reference C implementations

   Copyright 2012, Samuel Neves <sneves@dei.uc.pt>.  You may use this under the
   terms of the CC0, the OpenSSL Licence, or the Apache Public License 2.0, at
   your option.  The terms of these licenses can be found at:

   - CC0 1.0 Universal : http://creativecommons.org/publicdomain/zero/1.0
   - OpenSSL license   : https://www.openssl.org/source/license.html
   - Apache 2.0        : http://www.apache.org/licenses/LICENSE-2.0

   More information about the BLAKE2 hash function can be found at
   https://blake2.net.
*/

#include <stdint.h>
#include <string.h>
#include <stdio.h>

#include "blake2.h"
#include "blake2-impl.h"

static const uint64_t blake2b_IV[8] =
{
  0x6a09e667f3bcc908ULL, 0xbb67ae8584caa73bULL,
  0x3c6ef372fe94f82bULL, 0xa54ff53a5f1d36f1ULL,
  0x510e527fade682d1ULL, 0x9b05688c2b3e6c1fULL,
  0x1f83d9abfb41bd6bULL, 0x5be0cd19137e2179ULL
};

static const uint8_t blake2b_sigma[12][16] =
{
  {  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15 } ,
  { 14, 10,  4,  8,  9, 15, 13,  6,  1, 12,  0,  2, 11,  7,  5,  3 } ,
  { 11,  8, 12,  0,  5,  2, 15, 13, 10, 14,  3,  6,  7,  1,  9,  4 } ,
  {  7,  9,  3,  1, 13, 12, 11, 14,  2,  6,  5, 10,  4,  0, 15,  8 } ,
  {  9,  0,  5,  7,  2,  4, 10, 15, 14,  1, 11, 12,  6,  8,  3, 13 } ,
  {  2, 12,  6, 10,  0, 11,  8,  3,  4, 13,  7,  5, 15, 14,  1,  9 } ,
  { 12,  5,  1, 15, 14, 13,  4, 10,  0,  7,  6,  3,  9,  2,  8, 11 } ,
  { 13, 11,  7, 14, 12,  1,  3,  9,  5,  0, 15,  4,  8,  6,  2, 10 } ,
  {  6, 15, 14,  9, 11,  3,  0,  8, 12,  2, 13,  7,  1,  4, 10,  5 } ,
  { 10,  2,  8,  4,  7,  6,  1,  5, 15, 11,  9, 14,  3, 12, 13 , 0 } ,
  {  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15 } ,
  { 14, 10,  4,  8,  9, 15, 13,  6,  1, 12,  0,  2, 11,  7,  5,  3 }
};


static void blake2b_set_lastnode( blake2b_state *S )
{
  S->f[1] = (uint64_t)-1;
}

/* Some helper functions, not necessarily useful */
static int blake2b_is_lastblock( const blake2b_state *S )
{
  return S->f[0] != 0;
}

static void blake2b_set_lastblock( blake2b_state *S )
{
  if( S->last_node ) blake2b_set_lastnode( S );

  S->f[0] = (uint64_t)-1;
}

static void blake2b_increment_counter( blake2b_state *S, const uint64_t inc )
{
  S->t[0] += inc;
  S->t[1] += ( S->t[0] < inc );
}

static void blake2b_init0( blake2b_state *S )
{
  size_t i;
  memset( S, 0, sizeof( blake2b_state ) );

  for( i = 0; i < 8; ++i ) S->h[i] = blake2b_IV[i];
}

/* init xors IV with input parameter block */
int blake2b_init_param( blake2b_state *S, const blake2b_param *P )
{
  const uint8_t *p = ( const uint8_t * )( P );
  size_t i;

  blake2b_init0( S );

  /* IV XOR ParamBlock */
  for( i = 0; i < 8; ++i )
    S->h[i] ^= load64( p + sizeof( S->h[i] ) * i );

  S->outlen = P->digest_length;
  return 0;
}



int blake2b_init( blake2b_state *S, size_t outlen )
{
  blake2b_param P[1];

  if ( ( !outlen ) || ( outlen > BLAKE2B_OUTBYTES ) ) return -1;

  P->digest_length = (uint8_t)outlen;
  P->key_length    = 0;
  P->fanout        = 1;
  P->depth         = 1;
  store32( &P->leaf_length, 0 );
  store32( &P->node_offset, 0 );
  store32( &P->xof_length, 0 );
  P->node_depth    = 0;
  P->inner_length  = 0;
  memset( P->reserved, 0, sizeof( P->reserved ) );
  memset( P->salt,     0, sizeof( P->salt ) );
  memset( P->personal, 0, sizeof( P->personal ) );
  return blake2b_init_param( S, P );
}

#define G(r,i,a,b,c,d)                      \
  do {                                      \
    a = a + b + m[blake2b_sigma[r][2*i+0]]; \
    d = rotr64(d ^ a, 32);                  \
    c = c + d;                              \
    b = rotr64(b ^ c, 24);                  \
    a = a + b + m[blake2b_sigma[r][2*i+1]]; \
    d = rotr64(d ^ a, 16);                  \
    c = c + d;                              \
    b = rotr64(b ^ c, 63);                  \
  } while(0)

#define ROUND(r)                    \
  do {                              \
    G(r,0,v[ 0],v[ 4],v[ 8],v[12]); \
    G(r,1,v[ 1],v[ 5],v[ 9],v[13]); \
    G(r,2,v[ 2],v[ 6],v[10],v[14]); \
    G(r,3,v[ 3],v[ 7],v[11],v[15]); \
    G(r,4,v[ 0],v[ 5],v[10],v[15]); \
    G(r,5,v[ 1],v[ 6],v[11],v[12]); \
    G(r,6,v[ 2],v[ 7],v[ 8],v[13]); \
    G(r,7,v[ 3],v[ 4],v[ 9],v[14]); \
  } while(0)

static void blake2b_compress( blake2b_state *S, const uint8_t block[BLAKE2B_BLOCKBYTES] )
{
  uint64_t m[16];
  uint64_t v[16];
  size_t i;

  for( i = 0; i < 16; ++i ) {
    m[i] = load64( block + i * sizeof( m[i] ) );
  }

  for( i = 0; i < 8; ++i ) {
    v[i] = S->h[i];
  }

  v[ 8] = blake2b_IV[0];
  v[ 9] = blake2b_IV[1];
  v[10] = blake2b_IV[2];
  v[11] = blake2b_IV[3];
  v[12] = blake2b_IV[4] ^ S->t[0];
  v[13] = blake2b_IV[5] ^ S->t[1];
  v[14] = blake2b_IV[6] ^ S->f[0];
  v[15] = blake2b_IV[7] ^ S->f[1];

  ROUND( 0 );
  ROUND( 1 );
  ROUND( 2 );
  ROUND( 3 );
  ROUND( 4 );
  ROUND( 5 );
  ROUND( 6 );
  ROUND( 7 );
  ROUND( 8 );
  ROUND( 9 );
  ROUND( 10 );
  ROUND( 11 );

  for( i = 0; i < 8; ++i ) {
    S->h[i] = S->h[i] ^ v[i] ^ v[i + 8];
  }
}

#undef G
#undef ROUND

int blake2b_update( blake2b_state *S, const void *pin, size_t inlen )
{
  const unsigned char * in = (const unsigned char *)pin;
  if( inlen > 0 )
  {
    size_t left = S->buflen;
    size_t fill = BLAKE2B_BLOCKBYTES - left;
    if( inlen > fill )
    {
      S->buflen = 0;
      memcpy( S->buf + left, in, fill ); /* Fill buffer */
      blake2b_increment_counter( S, BLAKE2B_BLOCKBYTES );
      blake2b_compress( S, S->buf ); /* Compress */
      in += fill; inlen -= fill;
      while(inlen > BLAKE2B_BLOCKBYTES) {
        blake2b_increment_counter(S, BLAKE2B_BLOCKBYTES);
        blake2b_compress( S, in );
        in += BLAKE2B_BLOCKBYTES;
        inlen -= BLAKE2B_BLOCKBYTES;
      }
    }
    memcpy( S->buf + S->buflen, in, inlen );
    S->buflen += inlen;
  }
  return 0;
}

int blake2b_final( blake2b_state *S, void *out, size_t outlen )
{
  uint8_t buffer[BLAKE2B_OUTBYTES] = {0};
  size_t i;

  if( out == NULL || outlen < S->outlen )
    return -1;

  if( blake2b_is_lastblock( S ) )
    return -1;

  blake2b_increment_counter( S, S->buflen );
  blake2b_set_lastblock( S );
  memset( S->buf + S->buflen, 0, BLAKE2B_BLOCKBYTES - S->buflen ); /* Padding */
  blake2b_compress( S, S->buf );

  for( i = 0; i < 8; ++i ) /* Output full hash to temp buffer */
    store64( buffer + sizeof( S->h[i] ) * i, S->h[i] );

  memcpy( out, buffer, S->outlen );
  secure_zero_memory(buffer, sizeof(buffer));
  return 0;
}
