/* Crypto/Sha256.c -- SHA-256 Hash

2017-04-03 : Igor Pavlov : Public domain

This code is based on public domain code from Wei Dai's Crypto++ library. */

#include "Precomp.h"

#include <string.h>

#include "CpuArch.h"

#include "RotateDefs.h"

#include "Sha256.h"

/* define it for speed optimization */

#ifndef _SFX

#define _SHA256_UNROLL

#define _SHA256_UNROLL2

#endif

/* #define _SHA256_UNROLL2 */

void Sha256_Init(CSha256 *p)

{

  p->state[0] = 0x6a09e667;

  p->state[1] = 0xbb67ae85;

  p->state[2] = 0x3c6ef372;

  p->state[3] = 0xa54ff53a;

  p->state[4] = 0x510e527f;

  p->state[5] = 0x9b05688c;

  p->state[6] = 0x1f83d9ab;

  p->state[7] = 0x5be0cd19;

  p->count = 0;

}

#define S0(x) (rotrFixed(x, 2) ^ rotrFixed(x,13) ^ rotrFixed(x, 22))

#define S1(x) (rotrFixed(x, 6) ^ rotrFixed(x,11) ^ rotrFixed(x, 25))

#define s0(x) (rotrFixed(x, 7) ^ rotrFixed(x,18) ^ (x >> 3))

#define s1(x) (rotrFixed(x,17) ^ rotrFixed(x,19) ^ (x >> 10))

#define blk0(i) (W[i])

#define blk2(i) (W[i] += s1(W[((i)-2)&15]) + W[((i)-7)&15] + s0(W[((i)-15)&15]))

#define Ch(x,y,z) (z^(x&(y^z)))

#define Maj(x,y,z) ((x&y)|(z&(x|y)))

#ifdef _SHA256_UNROLL2

#define R(a,b,c,d,e,f,g,h, i) \

    h += S1(e) + Ch(e,f,g) + K[(i)+(size_t)(j)] + (j ? blk2(i) : blk0(i)); \

    d += h; \

    h += S0(a) + Maj(a, b, c)

#define RX_8(i) \

  R(a,b,c,d,e,f,g,h, i); \

  R(h,a,b,c,d,e,f,g, i+1); \

  R(g,h,a,b,c,d,e,f, i+2); \

  R(f,g,h,a,b,c,d,e, i+3); \

  R(e,f,g,h,a,b,c,d, i+4); \

  R(d,e,f,g,h,a,b,c, i+5); \

  R(c,d,e,f,g,h,a,b, i+6); \

  R(b,c,d,e,f,g,h,a, i+7)

#define RX_16  RX_8(0); RX_8(8);

#else

#define a(i) T[(0-(i))&7]

#define b(i) T[(1-(i))&7]

#define c(i) T[(2-(i))&7]

#define d(i) T[(3-(i))&7]

#define e(i) T[(4-(i))&7]

#define f(i) T[(5-(i))&7]

#define g(i) T[(6-(i))&7]

#define h(i) T[(7-(i))&7]

#define R(i) \

    h(i) += S1(e(i)) + Ch(e(i),f(i),g(i)) + K[(i)+(size_t)(j)] + (j ? blk2(i) : blk0(i)); \

    d(i) += h(i); \

    h(i) += S0(a(i)) + Maj(a(i), b(i), c(i)) \

#ifdef _SHA256_UNROLL

#define RX_8(i)  R(i+0); R(i+1); R(i+2); R(i+3); R(i+4); R(i+5); R(i+6); R(i+7);

#define RX_16  RX_8(0); RX_8(8);

#else

#define RX_16  unsigned i; for (i = 0; i < 16; i++) { R(i); }

#endif

#endif

static const UInt32 K[64] = {

  0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,

  0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,

  0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,

  0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,

  0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,

  0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,

  0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,

  0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,

  0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,

  0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,

  0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,

  0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,

  0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,

  0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,

  0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,

  0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2

};

static void Sha256_WriteByteBlock(CSha256 *p)

{

  UInt32 W[16];

  unsigned j;

  UInt32 *state;

  #ifdef _SHA256_UNROLL2

  UInt32 a,b,c,d,e,f,g,h;

  #else

  UInt32 T[8];

  #endif

  for (j = 0; j < 16; j += 4)

  {

    const Byte *ccc = p->buffer + j * 4;

    W[j    ] = GetBe32(ccc);

    W[j + 1] = GetBe32(ccc + 4);

    W[j + 2] = GetBe32(ccc + 8);

    W[j + 3] = GetBe32(ccc + 12);

  }

  state = p->state;

  #ifdef _SHA256_UNROLL2

  a = state[0];

  b = state[1];

  c = state[2];

  d = state[3];

  e = state[4];

  f = state[5];

  g = state[6];

  h = state[7];

  #else

  for (j = 0; j < 8; j++)

    T[j] = state[j];

  #endif

  for (j = 0; j < 64; j += 16)

  {

    RX_16

  }

  #ifdef _SHA256_UNROLL2

  state[0] += a;

  state[1] += b;

  state[2] += c;

  state[3] += d;

  state[4] += e;

  state[5] += f;

  state[6] += g;

  state[7] += h;

  #else

  for (j = 0; j < 8; j++)

    state[j] += T[j];

  #endif

  /* Wipe variables */

  /* memset(W, 0, sizeof(W)); */

  /* memset(T, 0, sizeof(T)); */

}

#undef S0

#undef S1

#undef s0

#undef s1

void Sha256_Update(CSha256 *p, const Byte *data, size_t size)

{

  if (size == 0)

    return;

  {

    unsigned pos = (unsigned)p->count & 0x3F;

    unsigned num;

    p->count += size;

    num = 64 - pos;

    if (num > size)

    {

      memcpy(p->buffer + pos, data, size);

      return;

    }

    size -= num;

    memcpy(p->buffer + pos, data, num);

    data += num;

  }

  for (;;)

  {

    Sha256_WriteByteBlock(p);

    if (size < 64)

      break;

    size -= 64;

    memcpy(p->buffer, data, 64);

    data += 64;

  }

  if (size != 0)

    memcpy(p->buffer, data, size);

}

void Sha256_Final(CSha256 *p, Byte *digest)

{

  unsigned pos = (unsigned)p->count & 0x3F;

  unsigned i;

  p->buffer[pos++] = 0x80;

  while (pos != (64 - 8))

  {

    pos &= 0x3F;

    if (pos == 0)

      Sha256_WriteByteBlock(p);

    p->buffer[pos++] = 0;

  }

  {

    UInt64 numBits = (p->count << 3);

    SetBe32(p->buffer + 64 - 8, (UInt32)(numBits >> 32));

    SetBe32(p->buffer + 64 - 4, (UInt32)(numBits));

  }

  Sha256_WriteByteBlock(p);

  for (i = 0; i < 8; i += 2)

  {

    UInt32 v0 = p->state[i];

    UInt32 v1 = p->state[i + 1];

    SetBe32(digest    , v0);

    SetBe32(digest + 4, v1);

    digest += 8;

  }

  Sha256_Init(p);

}