/*

   BLAKE reference C implementation

   Copyright (c) 2012 Jean-Philippe Aumasson <jeanphilippe.aumasson@gmail.com>

   To the extent possible under law, the author(s) have dedicated all copyright

   and related and neighboring rights to this software to the public domain

   worldwide. This software is distributed without any warranty.

   You should have received a copy of the CC0 Public Domain Dedication along with

   this software. If not, see <http://creativecommons.org/publicdomain/zero/1.0/>.

 */

#include "blake256.h"

#include <string.h>

#define U8TO32_BIG(p)               \

  (((uint32_t)((p)[0]) << 24) | ((uint32_t)((p)[1]) << 16) |  \

   ((uint32_t)((p)[2]) <<  8) | ((uint32_t)((p)[3])      ))

#define U32TO8_BIG(p, v)                \

  (p)[0] = (uint8_t)((v) >> 24); (p)[1] = (uint8_t)((v) >> 16); \

  (p)[2] = (uint8_t)((v) >>  8); (p)[3] = (uint8_t)((v)      );

static const uint8_t sigma[][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 },

  {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 }

};

static const uint32_t u256[16] =

{

  0x243f6a88, 0x85a308d3, 0x13198a2e, 0x03707344,

  0xa4093822, 0x299f31d0, 0x082efa98, 0xec4e6c89,

  0x452821e6, 0x38d01377, 0xbe5466cf, 0x34e90c6c,

  0xc0ac29b7, 0xc97c50dd, 0x3f84d5b5, 0xb5470917

};

static const uint8_t padding[129] =

{

  0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,

  0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0

};

static void blake256_compress( BLAKE256_CTX *S, const uint8_t *block )

{

  uint32_t v[16] = {0}, m[16] = {0}, i = 0;

#define ROT(x,n) (((x)<<(32-n))|( (x)>>(n)))

#define G(a,b,c,d,e)          \

  v[a] += (m[sigma[i][e]] ^ u256[sigma[i][e+1]]) + v[b]; \

  v[d] = ROT( v[d] ^ v[a],16);        \

  v[c] += v[d];           \

  v[b] = ROT( v[b] ^ v[c],12);        \

  v[a] += (m[sigma[i][e+1]] ^ u256[sigma[i][e]])+v[b]; \

  v[d] = ROT( v[d] ^ v[a], 8);        \

  v[c] += v[d];           \

  v[b] = ROT( v[b] ^ v[c], 7);

  for( i = 0; i < 16; ++i )  m[i] = U8TO32_BIG( block + i * 4 );

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

  v[ 8] = S->s[0] ^ u256[0];

  v[ 9] = S->s[1] ^ u256[1];

  v[10] = S->s[2] ^ u256[2];

  v[11] = S->s[3] ^ u256[3];

  v[12] = u256[4];

  v[13] = u256[5];

  v[14] = u256[6];

  v[15] = u256[7];

  /* don't xor t when the block is only padding */

  if ( !S->nullt )

  {

    v[12] ^= S->t[0];

    v[13] ^= S->t[0];

    v[14] ^= S->t[1];

    v[15] ^= S->t[1];

  }

  for( i = 0; i < 14; ++i )

  {

    /* column step */

    G( 0,  4,  8, 12,  0 );

    G( 1,  5,  9, 13,  2 );

    G( 2,  6, 10, 14,  4 );

    G( 3,  7, 11, 15,  6 );

    /* diagonal step */

    G( 0,  5, 10, 15,  8 );

    G( 1,  6, 11, 12, 10 );

    G( 2,  7,  8, 13, 12 );

    G( 3,  4,  9, 14, 14 );

  }

  for( i = 0; i < 16; ++i )  S->h[i % 8] ^= v[i];

  for( i = 0; i < 8 ; ++i )  S->h[i] ^= S->s[i % 4];

}

void blake256_Init( BLAKE256_CTX *S )

{

  S->h[0] = 0x6a09e667;

  S->h[1] = 0xbb67ae85;

  S->h[2] = 0x3c6ef372;

  S->h[3] = 0xa54ff53a;

  S->h[4] = 0x510e527f;

  S->h[5] = 0x9b05688c;

  S->h[6] = 0x1f83d9ab;

  S->h[7] = 0x5be0cd19;

  S->t[0] = S->t[1] = S->buflen = S->nullt = 0;

  S->s[0] = S->s[1] = S->s[2] = S->s[3] = 0;

}

void blake256_Update( BLAKE256_CTX *S, const uint8_t *in, size_t inlen )

{

  size_t left = S->buflen;

  size_t fill = 64 - left;

  /* data left and data received fill a block  */

  if( left && ( inlen >= fill ) )

  {

    memcpy( ( void * ) ( S->buf + left ), ( void * ) in, fill );

    S->t[0] += 512;

    if ( S->t[0] == 0 ) S->t[1]++;

    blake256_compress( S, S->buf );

    in += fill;

    inlen  -= fill;

    left = 0;

  }

  /* compress blocks of data received */

  while( inlen >= 64 )

  {

    S->t[0] += 512;

    if ( S->t[0] == 0 ) S->t[1]++;

    blake256_compress( S, in );

    in += 64;

    inlen -= 64;

  }

  /* store any data left */

  if( inlen > 0 )

  {

    memcpy( ( void * ) ( S->buf + left ),   \

            ( void * ) in, ( size_t ) inlen );

  }

  S->buflen = left + inlen;

}

void blake256_Final( BLAKE256_CTX *S, uint8_t *out )

{

  uint8_t msglen[8] = {0}, zo = 0x01, oo = 0x81;

  uint32_t lo = S->t[0] + ( S->buflen << 3 ), hi = S->t[1];

  /* support for hashing more than 2^32 bits */

  if ( lo < ( S->buflen << 3 ) ) hi++;

  U32TO8_BIG(  msglen + 0, hi );

  U32TO8_BIG(  msglen + 4, lo );

  if ( S->buflen == 55 )   /* one padding byte */

  {

    S->t[0] -= 8;

    blake256_Update( S, &oo, 1 );

  }

  else

  {

    if ( S->buflen < 55 )   /* enough space to fill the block  */

    {

      if ( !S->buflen ) S->nullt = 1;

      S->t[0] -= 440 - ( S->buflen << 3 );

      blake256_Update( S, padding, 55 - S->buflen );

    }

    else   /* need 2 compressions */

    {

      S->t[0] -= 512 - ( S->buflen << 3 );

      blake256_Update( S, padding, 64 - S->buflen );

      S->t[0] -= 440;

      blake256_Update( S, padding + 1, 55 );

      S->nullt = 1;

    }

    blake256_Update( S, &zo, 1 );

    S->t[0] -= 8;

  }

  S->t[0] -= 64;

  blake256_Update( S, msglen, 8 );

  U32TO8_BIG( out + 0, S->h[0] );

  U32TO8_BIG( out + 4, S->h[1] );

  U32TO8_BIG( out + 8, S->h[2] );

  U32TO8_BIG( out + 12, S->h[3] );

  U32TO8_BIG( out + 16, S->h[4] );

  U32TO8_BIG( out + 20, S->h[5] );

  U32TO8_BIG( out + 24, S->h[6] );

  U32TO8_BIG( out + 28, S->h[7] );

}

void blake256( const uint8_t *in, size_t inlen, uint8_t *out )

{

  BLAKE256_CTX S = {0};

  blake256_Init( &S );

  blake256_Update( &S, in, inlen );

  blake256_Final( &S, out );

}