text: /* 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 "avb_sha.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;                                                        \
    }
  
  static const uint32_t sha256_h0[8] = {0x6a09e667,
                                        0xbb67ae85,
                                        0x3c6ef372,
                                        0xa54ff53a,
                                        0x510e527f,
                                        0x9b05688c,
                                        0x1f83d9ab,
                                        0x5be0cd19};
  
  static const 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 avb_sha256_init(AvbSHA256Ctx* 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(AvbSHA256Ctx* 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 avb_sha256_update(AvbSHA256Ctx* 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 = AVB_SHA256_BLOCK_SIZE - ctx->len;
    rem_len = len < tmp_len ? len : tmp_len;
  
    avb_memcpy(&ctx->block[ctx->len], data, rem_len);
  
    if (ctx->len + len < AVB_SHA256_BLOCK_SIZE) {
      ctx->len += len;
      return;
    }
  
    new_len = len - rem_len;
    block_nb = new_len / AVB_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 % AVB_SHA256_BLOCK_SIZE;
  
    avb_memcpy(ctx->block, &shifted_data[block_nb << 6], rem_len);
  
    ctx->len = rem_len;
    ctx->tot_len += (block_nb + 1) << 6;
  }
  
  uint8_t* avb_sha256_final(AvbSHA256Ctx* ctx) {
    unsigned int block_nb;
    unsigned int pm_len;
    unsigned int len_b;
  #ifndef UNROLL_LOOPS
    int i;
  #endif
  
    block_nb =
        (1 + ((AVB_SHA256_BLOCK_SIZE - 9) < (ctx->len % AVB_SHA256_BLOCK_SIZE)));
  
    len_b = (ctx->tot_len + ctx->len) << 3;
    pm_len = block_nb << 6;
  
    avb_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;
  }
  