/*

 * Copyright (c) 2006 Kungliga Tekniska Högskolan

 * (Royal Institute of Technology, Stockholm, Sweden).

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 *

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 *

 * 3. Neither the name of the Institute nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <config.h>

#include <roken.h>

#include "hash.h"

#include "sha.h"

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

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

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

#define Sigma0(x) (ROTR(x,2)  ^ ROTR(x,13) ^ ROTR(x,22))

#define Sigma1(x) (ROTR(x,6)  ^ ROTR(x,11) ^ ROTR(x,25))

#define sigma0(x) (ROTR(x,7)  ^ ROTR(x,18) ^ ((x)>>3))

#define sigma1(x) (ROTR(x,17) ^ ROTR(x,19) ^ ((x)>>10))

#define A m->counter[0]

#define B m->counter[1]

#define C m->counter[2]

#define D m->counter[3]

#define E m->counter[4]

#define F m->counter[5]

#define G m->counter[6]

#define H m->counter[7]

static const uint32_t constant_256[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

};

int

SHA256_Init (SHA256_CTX *m)

{

    m->sz[0] = 0;

    m->sz[1] = 0;

    A = 0x6a09e667;

    B = 0xbb67ae85;

    C = 0x3c6ef372;

    D = 0xa54ff53a;

    E = 0x510e527f;

    F = 0x9b05688c;

    G = 0x1f83d9ab;

    H = 0x5be0cd19;

    return 1;

}

static void

calc (SHA256_CTX *m, uint32_t *in)

{

    uint32_t AA, BB, CC, DD, EE, FF, GG, HH;

    uint32_t data[64];

    int i;

    AA = A;

    BB = B;

    CC = C;

    DD = D;

    EE = E;

    FF = F;

    GG = G;

    HH = H;

    for (i = 0; i < 16; ++i)

  data[i] = in[i];

    for (i = 16; i < 64; ++i)

  data[i] = sigma1(data[i-2]) + data[i-7] +

      sigma0(data[i-15]) + data[i - 16];

    for (i = 0; i < 64; i++) {

  uint32_t T1, T2;

  T1 = HH + Sigma1(EE) + Ch(EE, FF, GG) + constant_256[i] + data[i];

  T2 = Sigma0(AA) + Maj(AA,BB,CC);

  HH = GG;

  GG = FF;

  FF = EE;

  EE = DD + T1;

  DD = CC;

  CC = BB;

  BB = AA;

  AA = T1 + T2;

    }

    A += AA;

    B += BB;

    C += CC;

    D += DD;

    E += EE;

    F += FF;

    G += GG;

    H += HH;

}

/*

 * From `Performance analysis of MD5' by Joseph D. Touch <touch@isi.edu>

 */

#if !defined(WORDS_BIGENDIAN) || defined(_CRAY)

static inline uint32_t

swap_uint32_t (uint32_t t)

{

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

    uint32_t temp1, temp2;

    temp1   = cshift(t, 16);

    temp2   = temp1 >> 8;

    temp1  &= 0x00ff00ff;

    temp2  &= 0x00ff00ff;

    temp1 <<= 8;

    return temp1 | temp2;

}

#endif

struct x32{

    unsigned int a:32;

    unsigned int b:32;

};

int

SHA256_Update (SHA256_CTX *m, const void *v, size_t len)

{

    const unsigned char *p = v;

    size_t old_sz = m->sz[0];

    size_t offset;

    m->sz[0] += len * 8;

    if (m->sz[0] < old_sz)

  ++m->sz[1];

    offset = (old_sz / 8) % 64;

    while(len > 0){

  size_t l = min(len, 64 - offset);

  memcpy(m->save + offset, p, l);

  offset += l;

  p += l;

  len -= l;

  if(offset == 64){

#if !defined(WORDS_BIGENDIAN) || defined(_CRAY)

      int i;

      uint32_t current[16];

      struct x32 *us = (struct x32*)m->save;

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

    current[2*i+0] = swap_uint32_t(us[i].a);

    current[2*i+1] = swap_uint32_t(us[i].b);

      }

      calc(m, current);

#else

      calc(m, (uint32_t*)m->save);

#endif

      offset = 0;

  }

    }

    return 1;

}

int

SHA256_Final (void *res, SHA256_CTX *m)

{

    unsigned char zeros[72];

    unsigned offset = (m->sz[0] / 8) % 64;

    unsigned int dstart = (120 - offset - 1) % 64 + 1;

    *zeros = 0x80;

    memset (zeros + 1, 0, sizeof(zeros) - 1);

    zeros[dstart+7] = (m->sz[0] >> 0) & 0xff;

    zeros[dstart+6] = (m->sz[0] >> 8) & 0xff;

    zeros[dstart+5] = (m->sz[0] >> 16) & 0xff;

    zeros[dstart+4] = (m->sz[0] >> 24) & 0xff;

    zeros[dstart+3] = (m->sz[1] >> 0) & 0xff;

    zeros[dstart+2] = (m->sz[1] >> 8) & 0xff;

    zeros[dstart+1] = (m->sz[1] >> 16) & 0xff;

    zeros[dstart+0] = (m->sz[1] >> 24) & 0xff;

    SHA256_Update (m, zeros, dstart + 8);

    {

  int i;

  unsigned char *r = (unsigned char*)res;

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

      r[4*i+3] = m->counter[i] & 0xFF;

      r[4*i+2] = (m->counter[i] >> 8) & 0xFF;

      r[4*i+1] = (m->counter[i] >> 16) & 0xFF;

      r[4*i]   = (m->counter[i] >> 24) & 0xFF;

  }

    }

    return 1;

}