text: /*****************************************************************************/
  /* MD5 Hash calculation routines                                             */
  /*                                                                           */
  /* Copyright (C) 2016 Laszlo Arvai                                           */
  /* All rights reserved.                                                      */
  /*                                                                           */
  /* This software may be modified and distributed under the terms             */
  /* of the GNU General Public License.  See the LICENSE file for details.     */
  /*****************************************************************************/
  
  /*****************************************************************************/
  /* Includes                                                                  */
  /*****************************************************************************/
  #include <crcMD5.h>
  #include <sysRTOS.h>
  
  /*****************************************************************************/
  /* Constants                                                                 */
  /*****************************************************************************/
  #define T_MASK ((uint32_t)~0)
  
  /*****************************************************************************/
  /* Local function prototypes                                                 */
  /*****************************************************************************/
  static void crcMD5Process(crcMD5State* in_state, const uint8_t* in_data);
  
  /*****************************************************************************/
  /* Function implementation                                                   */
  /*****************************************************************************/
  
  ///////////////////////////////////////////////////////////////////////////////
  /// @brief Initializes MD5 engine
  /// @param in_state MD5 calcaulation engine state 
  void crcMD5Open(crcMD5State* in_state)
  {
      in_state->BitCount[0] = in_state->BitCount[1] = 0;
      in_state->DigestBuffer[0] = 0x67452301;
      in_state->DigestBuffer[1] = T_MASK ^ 0x10325476;
      in_state->DigestBuffer[2] = T_MASK ^ 0x67452301;
      in_state->DigestBuffer[3] = 0x10325476;
  }
  
  ///////////////////////////////////////////////////////////////////////////////
  /// @brief Updates MD5 hash using data from the specified buffer
  /// @param in_state Current state of the MD5 machine
  /// @param in_data Pointer to the data buffer
  /// @param in_length Number of bytes in the buffer
  void crcMD5Update(crcMD5State* in_state, const uint8_t* in_data, uint32_t in_length)
  {
  	const uint8_t *p = in_data;
  	int left = in_length;
  	int offset = (in_state->BitCount[0] >> 3) & 63;
  	uint32_t nbits = (uint32_t) (in_length << 3);
  	int copy;
  
  	if (in_length <= 0)
  		return;
  
  	// Update the message length.
  	in_state->BitCount[1] += in_length >> 29;
  	in_state->BitCount[0] += nbits;
  	if (in_state->BitCount[0] < nbits)
  		in_state->BitCount[1]++;
  
  	// Process an initial partial block.
  	if (offset)
  	{
  		copy = (offset + in_length > 64 ? 64 - offset : in_length);
  
  		sysMemCopy(in_state->InputBuffer + offset, p, copy);
  		if (offset + copy < 64)
  			return;
  
  		p += copy;
  		left -= copy;
  		crcMD5Process(in_state, in_state->InputBuffer);
  	}
  
  	// Process full blocks.
  	for (; left >= 64; p += 64, left -= 64)
  		crcMD5Process(in_state, p);
  
  	/* Process a final partial block. */
  	if (left)
  		memcpy(in_state->InputBuffer, p, left);
  }
  
  ///////////////////////////////////////////////////////////////////////////////
  /// @brief Finisghes MD5 calculation and returns hash value
  /// @param in_state Current state of the MD5 machine
  /// @param out_hash MD5 hash value
  void crcMD5Close(crcMD5State* in_state, crcMD5Hash* out_hash)
  {
      static const uint8_t pad[64] = 
  		{
  			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
      };
      uint8_t data[8];
      int i;
  
      // Save the length before padding.
      for (i = 0; i < 8; ++i)
  			data[i] = (uint8_t)(in_state->BitCount[i >> 2] >> ((i & 3) << 3));
  
      // Pad to 56 bytes mod 64.
      crcMD5Update(in_state, pad, ((55 - (in_state->BitCount[0] >> 3)) & 63) + 1);
  
      // Append the length.
      crcMD5Update(in_state, data, 8);
  
  		// copy hash value
      for (i = 0; i < crcMD5_HASH_SIZE; ++i)
  			out_hash->Hash[i] = (uint8_t)(in_state->DigestBuffer[i >> 2] >> ((i & 3) << 3));
  }
  
  ///////////////////////////////////////////////////////////////////////////////
  /// @brief Compares two MD5 has values, return true if they are equal
  /// @param in_hash1 First hash value to compare
  /// @param in_hash2 Second hash value to comapare
  /// @return True if hash values are equal
  bool crcMD5IsEqual(crcMD5Hash* in_hash1, crcMD5Hash* in_hash2)
  {
  	uint8_t index;
  	bool equal = true;
  
  	for (index = 0; index < crcMD5_HASH_SIZE && equal; index++)
  	{
  		if (in_hash1->Hash[index] != in_hash2->Hash[index])
  			equal = false;
  	}
  
  	return equal;
  }
  
  
  /*****************************************************************************/
  /* Internal routines                                                         */
  /*****************************************************************************/
  
  #define T1 /* 0xd76aa478 */ (T_MASK ^ 0x28955b87)
  #define T2 /* 0xe8c7b756 */ (T_MASK ^ 0x173848a9)
  #define T3    0x242070db
  #define T4 /* 0xc1bdceee */ (T_MASK ^ 0x3e423111)
  #define T5 /* 0xf57c0faf */ (T_MASK ^ 0x0a83f050)
  #define T6    0x4787c62a
  #define T7 /* 0xa8304613 */ (T_MASK ^ 0x57cfb9ec)
  #define T8 /* 0xfd469501 */ (T_MASK ^ 0x02b96afe)
  #define T9    0x698098d8
  #define T10 /* 0x8b44f7af */ (T_MASK ^ 0x74bb0850)
  #define T11 /* 0xffff5bb1 */ (T_MASK ^ 0x0000a44e)
  #define T12 /* 0x895cd7be */ (T_MASK ^ 0x76a32841)
  #define T13    0x6b901122
  #define T14 /* 0xfd987193 */ (T_MASK ^ 0x02678e6c)
  #define T15 /* 0xa679438e */ (T_MASK ^ 0x5986bc71)
  #define T16    0x49b40821
  #define T17 /* 0xf61e2562 */ (T_MASK ^ 0x09e1da9d)
  #define T18 /* 0xc040b340 */ (T_MASK ^ 0x3fbf4cbf)
  #define T19    0x265e5a51
  #define T20 /* 0xe9b6c7aa */ (T_MASK ^ 0x16493855)
  #define T21 /* 0xd62f105d */ (T_MASK ^ 0x29d0efa2)
  #define T22    0x02441453
  #define T23 /* 0xd8a1e681 */ (T_MASK ^ 0x275e197e)
  #define T24 /* 0xe7d3fbc8 */ (T_MASK ^ 0x182c0437)
  #define T25    0x21e1cde6
  #define T26 /* 0xc33707d6 */ (T_MASK ^ 0x3cc8f829)
  #define T27 /* 0xf4d50d87 */ (T_MASK ^ 0x0b2af278)
  #define T28    0x455a14ed
  #define T29 /* 0xa9e3e905 */ (T_MASK ^ 0x561c16fa)
  #define T30 /* 0xfcefa3f8 */ (T_MASK ^ 0x03105c07)
  #define T31    0x676f02d9
  #define T32 /* 0x8d2a4c8a */ (T_MASK ^ 0x72d5b375)
  #define T33 /* 0xfffa3942 */ (T_MASK ^ 0x0005c6bd)
  #define T34 /* 0x8771f681 */ (T_MASK ^ 0x788e097e)
  #define T35    0x6d9d6122
  #define T36 /* 0xfde5380c */ (T_MASK ^ 0x021ac7f3)
  #define T37 /* 0xa4beea44 */ (T_MASK ^ 0x5b4115bb)
  #define T38    0x4bdecfa9
  #define T39 /* 0xf6bb4b60 */ (T_MASK ^ 0x0944b49f)
  #define T40 /* 0xbebfbc70 */ (T_MASK ^ 0x4140438f)
  #define T41    0x289b7ec6
  #define T42 /* 0xeaa127fa */ (T_MASK ^ 0x155ed805)
  #define T43 /* 0xd4ef3085 */ (T_MASK ^ 0x2b10cf7a)
  #define T44    0x04881d05
  #define T45 /* 0xd9d4d039 */ (T_MASK ^ 0x262b2fc6)
  #define T46 /* 0xe6db99e5 */ (T_MASK ^ 0x1924661a)
  #define T47    0x1fa27cf8
  #define T48 /* 0xc4ac5665 */ (T_MASK ^ 0x3b53a99a)
  #define T49 /* 0xf4292244 */ (T_MASK ^ 0x0bd6ddbb)
  #define T50    0x432aff97
  #define T51 /* 0xab9423a7 */ (T_MASK ^ 0x546bdc58)
  #define T52 /* 0xfc93a039 */ (T_MASK ^ 0x036c5fc6)
  #define T53    0x655b59c3
  #define T54 /* 0x8f0ccc92 */ (T_MASK ^ 0x70f3336d)
  #define T55 /* 0xffeff47d */ (T_MASK ^ 0x00100b82)
  #define T56 /* 0x85845dd1 */ (T_MASK ^ 0x7a7ba22e)
  #define T57    0x6fa87e4f
  #define T58 /* 0xfe2ce6e0 */ (T_MASK ^ 0x01d3191f)
  #define T59 /* 0xa3014314 */ (T_MASK ^ 0x5cfebceb)
  #define T60    0x4e0811a1
  #define T61 /* 0xf7537e82 */ (T_MASK ^ 0x08ac817d)
  #define T62 /* 0xbd3af235 */ (T_MASK ^ 0x42c50dca)
  #define T63    0x2ad7d2bb
  #define T64 /* 0xeb86d391 */ (T_MASK ^ 0x14792c6e)
  
  ///////////////////////////////////////////////////////////////////////////////
  /// @brief Internal MD5 calculation helper routine
  static void crcMD5Process(crcMD5State* in_state, const uint8_t* in_data)
  {
      uint32_t a,b,c,d;
      uint32_t t;
      uint32_t xbuf[16];
      const uint32_t* X;
  
  		a = in_state->DigestBuffer[0];
  		b = in_state->DigestBuffer[1],
  		c = in_state->DigestBuffer[2];
  		d = in_state->DigestBuffer[3];
  
      if (!((in_data - (const uint8_t *)0) & 3)) 
  		{
  			X = (const uint32_t*)in_data;
  	  }
  		else
  		{
  			/* not aligned */
  			memcpy(xbuf, in_data, 64);
  			X = xbuf;
      }
  
  #define ROTATE_LEFT(x, n) (((x) << (n)) | ((x) >> (32 - (n))))
  
      /* Round 1. */
      /* Let [abcd k s i] denote the operation
         a = b + ((a + F(b,c,d) + X[k] + T[i]) <<< s). */
  #define F(x, y, z) (((x) & (y)) | (~(x) & (z)))
  #define SET(a, b, c, d, k, s, Ti)\
    t = a + F(b,c,d) + X[k] + Ti;\
    a = ROTATE_LEFT(t, s) + b
  
      /* Do the following 16 operations. */
      SET(a, b, c, d,  0,  7,  T1);
      SET(d, a, b, c,  1, 12,  T2);
      SET(c, d, a, b,  2, 17,  T3);
      SET(b, c, d, a,  3, 22,  T4);
      SET(a, b, c, d,  4,  7,  T5);
      SET(d, a, b, c,  5, 12,  T6);
      SET(c, d, a, b,  6, 17,  T7);
      SET(b, c, d, a,  7, 22,  T8);
      SET(a, b, c, d,  8,  7,  T9);
      SET(d, a, b, c,  9, 12, T10);
      SET(c, d, a, b, 10, 17, T11);
      SET(b, c, d, a, 11, 22, T12);
      SET(a, b, c, d, 12,  7, T13);
      SET(d, a, b, c, 13, 12, T14);
      SET(c, d, a, b, 14, 17, T15);
      SET(b, c, d, a, 15, 22, T16);
  #undef SET
  
       /* Round 2. */
       /* Let [abcd k s i] denote the operation
            a = b + ((a + G(b,c,d) + X[k] + T[i]) <<< s). */
  #define G(x, y, z) (((x) & (z)) | ((y) & ~(z)))
  #define SET(a, b, c, d, k, s, Ti)\
    t = a + G(b,c,d) + X[k] + Ti;\
    a = ROTATE_LEFT(t, s) + b
  
       /* Do the following 16 operations. */
      SET(a, b, c, d,  1,  5, T17);
      SET(d, a, b, c,  6,  9, T18);
      SET(c, d, a, b, 11, 14, T19);
      SET(b, c, d, a,  0, 20, T20);
      SET(a, b, c, d,  5,  5, T21);
      SET(d, a, b, c, 10,  9, T22);
      SET(c, d, a, b, 15, 14, T23);
      SET(b, c, d, a,  4, 20, T24);
      SET(a, b, c, d,  9,  5, T25);
      SET(d, a, b, c, 14,  9, T26);
      SET(c, d, a, b,  3, 14, T27);
      SET(b, c, d, a,  8, 20, T28);
      SET(a, b, c, d, 13,  5, T29);
      SET(d, a, b, c,  2,  9, T30);
      SET(c, d, a, b,  7, 14, T31);
      SET(b, c, d, a, 12, 20, T32);
  #undef SET
  
       /* Round 3. */
       /* Let [abcd k s t] denote the operation
            a = b + ((a + H(b,c,d) + X[k] + T[i]) <<< s). */
  #define H(x, y, z) ((x) ^ (y) ^ (z))
  #define SET(a, b, c, d, k, s, Ti)\
    t = a + H(b,c,d) + X[k] + Ti;\
    a = ROTATE_LEFT(t, s) + b
       /* Do the following 16 operations. */
      SET(a, b, c, d,  5,  4, T33);
      SET(d, a, b, c,  8, 11, T34);
      SET(c, d, a, b, 11, 16, T35);
      SET(b, c, d, a, 14, 23, T36);
      SET(a, b, c, d,  1,  4, T37);
      SET(d, a, b, c,  4, 11, T38);
      SET(c, d, a, b,  7, 16, T39);
      SET(b, c, d, a, 10, 23, T40);
      SET(a, b, c, d, 13,  4, T41);
      SET(d, a, b, c,  0, 11, T42);
      SET(c, d, a, b,  3, 16, T43);
      SET(b, c, d, a,  6, 23, T44);
      SET(a, b, c, d,  9,  4, T45);
      SET(d, a, b, c, 12, 11, T46);
      SET(c, d, a, b, 15, 16, T47);
      SET(b, c, d, a,  2, 23, T48);
  #undef SET
  
       /* Round 4. */
       /* Let [abcd k s t] denote the operation
            a = b + ((a + I(b,c,d) + X[k] + T[i]) <<< s). */
  #define I(x, y, z) ((y) ^ ((x) | ~(z)))
  #define SET(a, b, c, d, k, s, Ti)\
    t = a + I(b,c,d) + X[k] + Ti;\
    a = ROTATE_LEFT(t, s) + b
       /* Do the following 16 operations. */
      SET(a, b, c, d,  0,  6, T49);
      SET(d, a, b, c,  7, 10, T50);
      SET(c, d, a, b, 14, 15, T51);
      SET(b, c, d, a,  5, 21, T52);
      SET(a, b, c, d, 12,  6, T53);
      SET(d, a, b, c,  3, 10, T54);
      SET(c, d, a, b, 10, 15, T55);
      SET(b, c, d, a,  1, 21, T56);
      SET(a, b, c, d,  8,  6, T57);
      SET(d, a, b, c, 15, 10, T58);
      SET(c, d, a, b,  6, 15, T59);
      SET(b, c, d, a, 13, 21, T60);
      SET(a, b, c, d,  4,  6, T61);
      SET(d, a, b, c, 11, 10, T62);
      SET(c, d, a, b,  2, 15, T63);
      SET(b, c, d, a,  9, 21, T64);
  #undef SET
  
       /* Then perform the following additions. (That is increment each
          of the four registers by the value it had before this block
          was started.) */
  		in_state->DigestBuffer[0] += a;
      in_state->DigestBuffer[1] += b;
      in_state->DigestBuffer[2] += c;
      in_state->DigestBuffer[3] += d;
  }
  
  