/*
   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 uint32_t blake2s_IV[8] =
{
  0x6A09E667UL, 0xBB67AE85UL, 0x3C6EF372UL, 0xA54FF53AUL,
  0x510E527FUL, 0x9B05688CUL, 0x1F83D9ABUL, 0x5BE0CD19UL
};

static const uint8_t blake2s_sigma[10][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 } ,
};

BLAKE2_LOCAL_INLINE(int) blake2s_set_lastnode( blake2s_state *S )
{
  S->f[1] = -1;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_clear_lastnode( blake2s_state *S )
{
  S->f[1] = 0;
  return 0;
}

/* Some helper functions, not necessarily useful */
BLAKE2_LOCAL_INLINE(int) blake2s_is_lastblock( const blake2s_state *S )
{
  return S->f[0] != 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_set_lastblock( blake2s_state *S )
{
  if( S->last_node ) blake2s_set_lastnode( S );

  S->f[0] = -1;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_clear_lastblock( blake2s_state *S )
{
  if( S->last_node ) blake2s_clear_lastnode( S );

  S->f[0] = 0;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_increment_counter( blake2s_state *S, const uint32_t inc )
{
  S->t[0] += inc;
  S->t[1] += ( S->t[0] < inc );
  return 0;
}

/* Parameter-related functions */
BLAKE2_LOCAL_INLINE(int) blake2s_param_set_digest_length( blake2s_param *P, const uint8_t digest_length )
{
  P->digest_length = digest_length;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_param_set_fanout( blake2s_param *P, const uint8_t fanout )
{
  P->fanout = fanout;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_param_set_max_depth( blake2s_param *P, const uint8_t depth )
{
  P->depth = depth;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_param_set_leaf_length( blake2s_param *P, const uint32_t leaf_length )
{
  store32( &P->leaf_length, leaf_length );
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_param_set_node_offset( blake2s_param *P, const uint64_t node_offset )
{
  store48( P->node_offset, node_offset );
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_param_set_node_depth( blake2s_param *P, const uint8_t node_depth )
{
  P->node_depth = node_depth;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_param_set_inner_length( blake2s_param *P, const uint8_t inner_length )
{
  P->inner_length = inner_length;
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_param_set_salt( blake2s_param *P, const uint8_t salt[BLAKE2S_SALTBYTES] )
{
  memcpy( P->salt, salt, BLAKE2S_SALTBYTES );
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_param_set_personal( blake2s_param *P, const uint8_t personal[BLAKE2S_PERSONALBYTES] )
{
  memcpy( P->personal, personal, BLAKE2S_PERSONALBYTES );
  return 0;
}

BLAKE2_LOCAL_INLINE(int) blake2s_init0( blake2s_state *S )
{
  memset( S, 0, sizeof( blake2s_state ) );

  for( int i = 0; i < 8; ++i ) S->h[i] = blake2s_IV[i];

  return 0;
}

/* init2 xors IV with input parameter block */
int blake2s_init_param( blake2s_state *S, const blake2s_param *P )
{
  const uint32_t *p = ( const uint32_t * )( P );

  blake2s_init0( S );

  /* IV XOR ParamBlock */
  for( size_t i = 0; i < 8; ++i )
    S->h[i] ^= load32( &p[i] );

  return 0;
}


/* Sequential blake2s initialization */
int blake2s_init( blake2s_state *S, const uint8_t outlen )
{
  blake2s_param P[1];

  /* Move interval verification here? */
  if ( ( !outlen ) || ( outlen > BLAKE2S_OUTBYTES ) ) return -1;

  P->digest_length = outlen;
  P->key_length    = 0;
  P->fanout        = 1;
  P->depth         = 1;
  store32( &P->leaf_length, 0 );
  store48( &P->node_offset, 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 blake2s_init_param( S, P );
}

int blake2s_init_key( blake2s_state *S, const uint8_t outlen, const void *key, const uint8_t keylen )
{
  blake2s_param P[1];

  if ( ( !outlen ) || ( outlen > BLAKE2S_OUTBYTES ) ) return -1;

  if ( !key || !keylen || keylen > BLAKE2S_KEYBYTES ) return -1;

  P->digest_length = outlen;
  P->key_length    = keylen;
  P->fanout        = 1;
  P->depth         = 1;
  store32( &P->leaf_length, 0 );
  store48( &P->node_offset, 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 ) );

  if( blake2s_init_param( S, P ) < 0 ) return -1;

  {
    uint8_t block[BLAKE2S_BLOCKBYTES];
    memset( block, 0, BLAKE2S_BLOCKBYTES );
    memcpy( block, key, keylen );
    blake2s_update( S, block, BLAKE2S_BLOCKBYTES );
    secure_zero_memory( block, BLAKE2S_BLOCKBYTES ); /* Burn the key from stack */
  }
  return 0;
}

static int blake2s_compress( blake2s_state *S, const uint8_t block[BLAKE2S_BLOCKBYTES] )
{
  uint32_t m[16];
  uint32_t v[16];

  for( size_t i = 0; i < 16; ++i )
    m[i] = load32( block + i * sizeof( m[i] ) );

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

  v[ 8] = blake2s_IV[0];
  v[ 9] = blake2s_IV[1];
  v[10] = blake2s_IV[2];
  v[11] = blake2s_IV[3];
  v[12] = S->t[0] ^ blake2s_IV[4];
  v[13] = S->t[1] ^ blake2s_IV[5];
  v[14] = S->f[0] ^ blake2s_IV[6];
  v[15] = S->f[1] ^ blake2s_IV[7];
#define G(r,i,a,b,c,d) \
  do { \
    a = a + b + m[blake2s_sigma[r][2*i+0]]; \
    d = rotr32(d ^ a, 16); \
    c = c + d; \
    b = rotr32(b ^ c, 12); \
    a = a + b + m[blake2s_sigma[r][2*i+1]]; \
    d = rotr32(d ^ a, 8); \
    c = c + d; \
    b = rotr32(b ^ c, 7); \
  } 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)
  ROUND( 0 );
  ROUND( 1 );
  ROUND( 2 );
  ROUND( 3 );
  ROUND( 4 );
  ROUND( 5 );
  ROUND( 6 );
  ROUND( 7 );
  ROUND( 8 );
  ROUND( 9 );

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

#undef G
#undef ROUND
  return 0;
}


int blake2s_update( blake2s_state *S, const uint8_t *in, uint64_t inlen )
{
  while( inlen > 0 )
  {
    size_t left = S->buflen;
    size_t fill = 2 * BLAKE2S_BLOCKBYTES - left;

    if( inlen > fill )
    {
      memcpy( S->buf + left, in, fill ); /* Fill buffer */
      S->buflen += fill;
      blake2s_increment_counter( S, BLAKE2S_BLOCKBYTES );
      blake2s_compress( S, S->buf ); /* Compress */
      memcpy( S->buf, S->buf + BLAKE2S_BLOCKBYTES, BLAKE2S_BLOCKBYTES ); /* Shift buffer left */
      S->buflen -= BLAKE2S_BLOCKBYTES;
      in += fill;
      inlen -= fill;
    }
    else /* inlen <= fill */
    {
      memcpy( S->buf + left, in, inlen );
      S->buflen += inlen; /* Be lazy, do not compress */
      in += inlen;
      inlen -= inlen;
    }
  }

  return 0;
}

int blake2s_final( blake2s_state *S, uint8_t *out, uint8_t outlen )
{
  uint8_t buffer[BLAKE2S_OUTBYTES] = {0};

  if( out == NULL || outlen == 0 || outlen > BLAKE2S_OUTBYTES )
    return -1;

  if( blake2s_is_lastblock( S ) )
    return -1;


  if( S->buflen > BLAKE2S_BLOCKBYTES )
  {
    blake2s_increment_counter( S, BLAKE2S_BLOCKBYTES );
    blake2s_compress( S, S->buf );
    S->buflen -= BLAKE2S_BLOCKBYTES;
    memcpy( S->buf, S->buf + BLAKE2S_BLOCKBYTES, S->buflen );
  }

  blake2s_increment_counter( S, ( uint32_t )S->buflen );
  blake2s_set_lastblock( S );
  memset( S->buf + S->buflen, 0, 2 * BLAKE2S_BLOCKBYTES - S->buflen ); /* Padding */
  blake2s_compress( S, S->buf );

  for( int i = 0; i < 8; ++i ) /* Output full hash to temp buffer */
    store32( buffer + sizeof( S->h[i] ) * i, S->h[i] );
    
  memcpy( out, buffer, outlen );
  return 0;
}

int blake2s( uint8_t *out, const void *in, const void *key, const uint8_t outlen, const uint64_t inlen, uint8_t keylen )
{
  blake2s_state S[1];

  /* Verify parameters */
  if ( NULL == in && inlen > 0 ) return -1;

  if ( NULL == out ) return -1;

  if ( NULL == key && keylen > 0) return -1;

  if( !outlen || outlen > BLAKE2S_OUTBYTES ) return -1;

  if( keylen > BLAKE2S_KEYBYTES ) return -1;

  if( keylen > 0 )
  {
    if( blake2s_init_key( S, outlen, key, keylen ) < 0 ) return -1;
  }
  else
  {
    if( blake2s_init( S, outlen ) < 0 ) return -1;
  }

  blake2s_update( S, ( const uint8_t * )in, inlen );
  blake2s_final( S, out, outlen );
  return 0;
}

#if defined(SUPERCOP)
int crypto_hash( unsigned char *out, unsigned char *in, unsigned long long inlen )
{
  return blake2s( out, in, NULL, BLAKE2S_OUTBYTES, inlen, 0 );
}
#endif

#if defined(BLAKE2S_SELFTEST)
#include <string.h>
#include "blake2-kat.h"
int main( int argc, char **argv )
{
  uint8_t key[BLAKE2S_KEYBYTES];
  uint8_t buf[KAT_LENGTH];

  for( size_t i = 0; i < BLAKE2S_KEYBYTES; ++i )
    key[i] = ( uint8_t )i;

  for( size_t i = 0; i < KAT_LENGTH; ++i )
    buf[i] = ( uint8_t )i;

  for( size_t i = 0; i < KAT_LENGTH; ++i )
  {
    uint8_t hash[BLAKE2S_OUTBYTES];
    blake2s( hash, buf, key, BLAKE2S_OUTBYTES, i, BLAKE2S_KEYBYTES );

    if( 0 != memcmp( hash, blake2s_keyed_kat[i], BLAKE2S_OUTBYTES ) )
    {
      puts( "error" );
      return -1;
    }
  }

  puts( "ok" );
  return 0;
}
#endif