/* SHA-256 and SHA-512 implementation based on code by Oliver Gay
 * <olivier.gay@a3.epfl.ch> under a BSD-style license. See below.
 */

/*
 * FIPS 180-2 SHA-224/256/384/512 implementation
 * Last update: 02/02/2007
 * Issue date:  04/30/2005
 *
 * Copyright (C) 2005, 2007 Olivier Gay <olivier.gay@a3.epfl.ch>
 * 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 project 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 PROJECT 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 PROJECT 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 "cryptolib.h"
#include "utility.h"

#define SHFR(x, n)    (x >> n)
#define ROTR(x, n)   ((x >> n) | (x << ((sizeof(x) << 3) - n)))
#define ROTL(x, n)   ((x << n) | (x >> ((sizeof(x) << 3) - n)))
#define CH(x, y, z)  ((x & y) ^ (~x & z))
#define MAJ(x, y, z) ((x & y) ^ (x & z) ^ (y & z))

#define SHA256_F1(x) (ROTR(x,  2) ^ ROTR(x, 13) ^ ROTR(x, 22))
#define SHA256_F2(x) (ROTR(x,  6) ^ ROTR(x, 11) ^ ROTR(x, 25))
#define SHA256_F3(x) (ROTR(x,  7) ^ ROTR(x, 18) ^ SHFR(x,  3))
#define SHA256_F4(x) (ROTR(x, 17) ^ ROTR(x, 19) ^ SHFR(x, 10))

#define UNPACK32(x, str)                        \
  {                                             \
    *((str) + 3) = (uint8_t) ((x)      );       \
    *((str) + 2) = (uint8_t) ((x) >>  8);       \
    *((str) + 1) = (uint8_t) ((x) >> 16);       \
    *((str) + 0) = (uint8_t) ((x) >> 24);       \
  }

#define PACK32(str, x)                          \
  {                                             \
    *(x) =   ((uint32_t) *((str) + 3)      )    \
        | ((uint32_t) *((str) + 2) <<  8)       \
        | ((uint32_t) *((str) + 1) << 16)       \
        | ((uint32_t) *((str) + 0) << 24);      \
  }

/* Macros used for loops unrolling */

#define SHA256_SCR(i)                         \
  {                                           \
    w[i] =  SHA256_F4(w[i -  2]) + w[i -  7]  \
        + SHA256_F3(w[i - 15]) + w[i - 16];   \
  }

#define SHA256_EXP(a, b, c, d, e, f, g, h, j)               \
  {                                                         \
    t1 = wv[h] + SHA256_F2(wv[e]) + CH(wv[e], wv[f], wv[g]) \
        + sha256_k[j] + w[j];                               \
    t2 = SHA256_F1(wv[a]) + MAJ(wv[a], wv[b], wv[c]);       \
    wv[d] += t1;                                            \
    wv[h] = t1 + t2;                                        \
  }

uint32_t sha256_h0[8] = {
  0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
  0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19};

uint32_t sha256_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};


/* SHA-256 implementation */
void SHA256_init(SHA256_CTX *ctx) {
#ifndef UNROLL_LOOPS
    int i;
    for (i = 0; i < 8; i++) {
        ctx->h[i] = sha256_h0[i];
    }
#else
    ctx->h[0] = sha256_h0[0]; ctx->h[1] = sha256_h0[1];
    ctx->h[2] = sha256_h0[2]; ctx->h[3] = sha256_h0[3];
    ctx->h[4] = sha256_h0[4]; ctx->h[5] = sha256_h0[5];
    ctx->h[6] = sha256_h0[6]; ctx->h[7] = sha256_h0[7];
#endif /* !UNROLL_LOOPS */

    ctx->len = 0;
    ctx->tot_len = 0;
}


static void SHA256_transform(SHA256_CTX* ctx, const uint8_t* message,
                             unsigned int block_nb) {
  uint32_t w[64];
  uint32_t wv[8];
  uint32_t t1, t2;
  const unsigned char *sub_block;
  int i;

#ifndef UNROLL_LOOPS
  int j;
#endif

  for (i = 0; i < (int) block_nb; i++) {
    sub_block = message + (i << 6);

#ifndef UNROLL_LOOPS
    for (j = 0; j < 16; j++) {
      PACK32(&sub_block[j << 2], &w[j]);
    }

    for (j = 16; j < 64; j++) {
      SHA256_SCR(j);
    }

    for (j = 0; j < 8; j++) {
      wv[j] = ctx->h[j];
    }

    for (j = 0; j < 64; j++) {
      t1 = wv[7] + SHA256_F2(wv[4]) + CH(wv[4], wv[5], wv[6])
          + sha256_k[j] + w[j];
      t2 = SHA256_F1(wv[0]) + MAJ(wv[0], wv[1], wv[2]);
      wv[7] = wv[6];
      wv[6] = wv[5];
      wv[5] = wv[4];
      wv[4] = wv[3] + t1;
      wv[3] = wv[2];
      wv[2] = wv[1];
      wv[1] = wv[0];
      wv[0] = t1 + t2;
    }

    for (j = 0; j < 8; j++) {
      ctx->h[j] += wv[j];
    }
#else
    PACK32(&sub_block[ 0], &w[ 0]); PACK32(&sub_block[ 4], &w[ 1]);
    PACK32(&sub_block[ 8], &w[ 2]); PACK32(&sub_block[12], &w[ 3]);
    PACK32(&sub_block[16], &w[ 4]); PACK32(&sub_block[20], &w[ 5]);
    PACK32(&sub_block[24], &w[ 6]); PACK32(&sub_block[28], &w[ 7]);
    PACK32(&sub_block[32], &w[ 8]); PACK32(&sub_block[36], &w[ 9]);
    PACK32(&sub_block[40], &w[10]); PACK32(&sub_block[44], &w[11]);
    PACK32(&sub_block[48], &w[12]); PACK32(&sub_block[52], &w[13]);
    PACK32(&sub_block[56], &w[14]); PACK32(&sub_block[60], &w[15]);

    SHA256_SCR(16); SHA256_SCR(17); SHA256_SCR(18); SHA256_SCR(19);
    SHA256_SCR(20); SHA256_SCR(21); SHA256_SCR(22); SHA256_SCR(23);
    SHA256_SCR(24); SHA256_SCR(25); SHA256_SCR(26); SHA256_SCR(27);
    SHA256_SCR(28); SHA256_SCR(29); SHA256_SCR(30); SHA256_SCR(31);
    SHA256_SCR(32); SHA256_SCR(33); SHA256_SCR(34); SHA256_SCR(35);
    SHA256_SCR(36); SHA256_SCR(37); SHA256_SCR(38); SHA256_SCR(39);
    SHA256_SCR(40); SHA256_SCR(41); SHA256_SCR(42); SHA256_SCR(43);
    SHA256_SCR(44); SHA256_SCR(45); SHA256_SCR(46); SHA256_SCR(47);
    SHA256_SCR(48); SHA256_SCR(49); SHA256_SCR(50); SHA256_SCR(51);
    SHA256_SCR(52); SHA256_SCR(53); SHA256_SCR(54); SHA256_SCR(55);
    SHA256_SCR(56); SHA256_SCR(57); SHA256_SCR(58); SHA256_SCR(59);
    SHA256_SCR(60); SHA256_SCR(61); SHA256_SCR(62); SHA256_SCR(63);

    wv[0] = ctx->h[0]; wv[1] = ctx->h[1];
    wv[2] = ctx->h[2]; wv[3] = ctx->h[3];
    wv[4] = ctx->h[4]; wv[5] = ctx->h[5];
    wv[6] = ctx->h[6]; wv[7] = ctx->h[7];

    SHA256_EXP(0,1,2,3,4,5,6,7, 0); SHA256_EXP(7,0,1,2,3,4,5,6, 1);
    SHA256_EXP(6,7,0,1,2,3,4,5, 2); SHA256_EXP(5,6,7,0,1,2,3,4, 3);
    SHA256_EXP(4,5,6,7,0,1,2,3, 4); SHA256_EXP(3,4,5,6,7,0,1,2, 5);
    SHA256_EXP(2,3,4,5,6,7,0,1, 6); SHA256_EXP(1,2,3,4,5,6,7,0, 7);
    SHA256_EXP(0,1,2,3,4,5,6,7, 8); SHA256_EXP(7,0,1,2,3,4,5,6, 9);
    SHA256_EXP(6,7,0,1,2,3,4,5,10); SHA256_EXP(5,6,7,0,1,2,3,4,11);
    SHA256_EXP(4,5,6,7,0,1,2,3,12); SHA256_EXP(3,4,5,6,7,0,1,2,13);
    SHA256_EXP(2,3,4,5,6,7,0,1,14); SHA256_EXP(1,2,3,4,5,6,7,0,15);
    SHA256_EXP(0,1,2,3,4,5,6,7,16); SHA256_EXP(7,0,1,2,3,4,5,6,17);
    SHA256_EXP(6,7,0,1,2,3,4,5,18); SHA256_EXP(5,6,7,0,1,2,3,4,19);
    SHA256_EXP(4,5,6,7,0,1,2,3,20); SHA256_EXP(3,4,5,6,7,0,1,2,21);
    SHA256_EXP(2,3,4,5,6,7,0,1,22); SHA256_EXP(1,2,3,4,5,6,7,0,23);
    SHA256_EXP(0,1,2,3,4,5,6,7,24); SHA256_EXP(7,0,1,2,3,4,5,6,25);
    SHA256_EXP(6,7,0,1,2,3,4,5,26); SHA256_EXP(5,6,7,0,1,2,3,4,27);
    SHA256_EXP(4,5,6,7,0,1,2,3,28); SHA256_EXP(3,4,5,6,7,0,1,2,29);
    SHA256_EXP(2,3,4,5,6,7,0,1,30); SHA256_EXP(1,2,3,4,5,6,7,0,31);
    SHA256_EXP(0,1,2,3,4,5,6,7,32); SHA256_EXP(7,0,1,2,3,4,5,6,33);
    SHA256_EXP(6,7,0,1,2,3,4,5,34); SHA256_EXP(5,6,7,0,1,2,3,4,35);
    SHA256_EXP(4,5,6,7,0,1,2,3,36); SHA256_EXP(3,4,5,6,7,0,1,2,37);
    SHA256_EXP(2,3,4,5,6,7,0,1,38); SHA256_EXP(1,2,3,4,5,6,7,0,39);
    SHA256_EXP(0,1,2,3,4,5,6,7,40); SHA256_EXP(7,0,1,2,3,4,5,6,41);
    SHA256_EXP(6,7,0,1,2,3,4,5,42); SHA256_EXP(5,6,7,0,1,2,3,4,43);
    SHA256_EXP(4,5,6,7,0,1,2,3,44); SHA256_EXP(3,4,5,6,7,0,1,2,45);
    SHA256_EXP(2,3,4,5,6,7,0,1,46); SHA256_EXP(1,2,3,4,5,6,7,0,47);
    SHA256_EXP(0,1,2,3,4,5,6,7,48); SHA256_EXP(7,0,1,2,3,4,5,6,49);
    SHA256_EXP(6,7,0,1,2,3,4,5,50); SHA256_EXP(5,6,7,0,1,2,3,4,51);
    SHA256_EXP(4,5,6,7,0,1,2,3,52); SHA256_EXP(3,4,5,6,7,0,1,2,53);
    SHA256_EXP(2,3,4,5,6,7,0,1,54); SHA256_EXP(1,2,3,4,5,6,7,0,55);
    SHA256_EXP(0,1,2,3,4,5,6,7,56); SHA256_EXP(7,0,1,2,3,4,5,6,57);
    SHA256_EXP(6,7,0,1,2,3,4,5,58); SHA256_EXP(5,6,7,0,1,2,3,4,59);
    SHA256_EXP(4,5,6,7,0,1,2,3,60); SHA256_EXP(3,4,5,6,7,0,1,2,61);
    SHA256_EXP(2,3,4,5,6,7,0,1,62); SHA256_EXP(1,2,3,4,5,6,7,0,63);

    ctx->h[0] += wv[0]; ctx->h[1] += wv[1];
    ctx->h[2] += wv[2]; ctx->h[3] += wv[3];
    ctx->h[4] += wv[4]; ctx->h[5] += wv[5];
    ctx->h[6] += wv[6]; ctx->h[7] += wv[7];
#endif /* !UNROLL_LOOPS */
  }
}


void SHA256_update(SHA256_CTX* ctx, const uint8_t* data, uint32_t len) {
    unsigned int block_nb;
    unsigned int new_len, rem_len, tmp_len;
    const uint8_t *shifted_data;

    tmp_len = SHA256_BLOCK_SIZE - ctx->len;
    rem_len = len < tmp_len ? len : tmp_len;

    Memcpy(&ctx->block[ctx->len], data, rem_len);

    if (ctx->len + len < SHA256_BLOCK_SIZE) {
        ctx->len += len;
        return;
    }

    new_len = len - rem_len;
    block_nb = new_len / SHA256_BLOCK_SIZE;

    shifted_data = data + rem_len;

    SHA256_transform(ctx, ctx->block, 1);
    SHA256_transform(ctx, shifted_data, block_nb);

    rem_len = new_len % SHA256_BLOCK_SIZE;

    Memcpy(ctx->block, &shifted_data[block_nb << 6],
           rem_len);

    ctx->len = rem_len;
    ctx->tot_len += (block_nb + 1) << 6;
}

uint8_t* SHA256_final(SHA256_CTX* ctx) {
    unsigned int block_nb;
    unsigned int pm_len;
    unsigned int len_b;
#ifndef UNROLL_LOOPS
    int i;
#endif

    block_nb = (1 + ((SHA256_BLOCK_SIZE - 9)
                     < (ctx->len % SHA256_BLOCK_SIZE)));

    len_b = (ctx->tot_len + ctx->len) << 3;
    pm_len = block_nb << 6;

    Memset(ctx->block + ctx->len, 0, pm_len - ctx->len);
    ctx->block[ctx->len] = 0x80;
    UNPACK32(len_b, ctx->block + pm_len - 4);

    SHA256_transform(ctx, ctx->block, block_nb);

#ifndef UNROLL_LOOPS
    for (i = 0 ; i < 8; i++) {
        UNPACK32(ctx->h[i], &ctx->buf[i << 2]);
    }
#else
   UNPACK32(ctx->h[0], &ctx->buf[ 0]);
   UNPACK32(ctx->h[1], &ctx->buf[ 4]);
   UNPACK32(ctx->h[2], &ctx->buf[ 8]);
   UNPACK32(ctx->h[3], &ctx->buf[12]);
   UNPACK32(ctx->h[4], &ctx->buf[16]);
   UNPACK32(ctx->h[5], &ctx->buf[20]);
   UNPACK32(ctx->h[6], &ctx->buf[24]);
   UNPACK32(ctx->h[7], &ctx->buf[28]);
#endif /* !UNROLL_LOOPS */

   return ctx->buf;
}

uint8_t* internal_SHA256(const uint8_t* data, uint64_t len, uint8_t* digest) {
  const uint8_t* input_ptr;
  const uint8_t* result;
  uint64_t remaining_len;
  int i;
  SHA256_CTX ctx;

  SHA256_init(&ctx);

  input_ptr = data;
  remaining_len = len;

  /* Process data in at most UINT32_MAX byte chunks at a time. */
  while (remaining_len) {
    uint32_t block_size;
    block_size = (uint32_t) ((remaining_len >= UINT32_MAX) ?
                             UINT32_MAX : remaining_len);
    SHA256_update(&ctx, input_ptr, block_size);
    remaining_len -= block_size;
    input_ptr += block_size;
  }

  result = SHA256_final(&ctx);
  for (i = 0; i < SHA256_DIGEST_SIZE; ++i) {
    digest[i] = *result++;
  }
  return digest;
}