text: /* +------------------------------------------------------------------------+
     |                     Mobile Robot Programming Toolkit (MRPT)            |
     |                          https://www.mrpt.org/                         |
     |                                                                        |
     | Copyright (c) 2005-2019, Individual contributors, see AUTHORS file     |
     | See: https://www.mrpt.org/Authors - All rights reserved.               |
     | Released under BSD License. See: https://www.mrpt.org/License          |
     +------------------------------------------------------------------------+ */
  
  /* MD5
   converted to C++ class by Frank Thilo (thilo@unix-ag.org)
   for bzflag (http://www.bzflag.org)
  
     based on:
  
     md5.h and md5.c
     reference implemantion of RFC 1321
  
     Copyright (C) 1991-2, RSA Data Security, Inc. Created 1991. All
  rights reserved.
  
  License to copy and use this software is granted provided that it
  is identified as the "RSA Data Security, Inc. MD5 Message-Digest
  Algorithm" in all material mentioning or referencing this software
  or this function.
  
  License is also granted to make and use derivative works provided
  that such works are identified as "derived from the RSA Data
  Security, Inc. MD5 Message-Digest Algorithm" in all material
  mentioning or referencing the derived work.
  
  RSA Data Security, Inc. makes no representations concerning either
  the merchantability of this software or the suitability of this
  software for any particular purpose. It is provided "as is"
  without express or implied warranty of any kind.
  
  These notices must be retained in any copies of any part of this
  documentation and/or software.
  
  */
  
  #include "system-precomp.h"  // Precompiled headers
  
  #include <mrpt/core/common.h>  // MSVC warnings
  #include <mrpt/core/exceptions.h>  // ASSERT_
  #include <mrpt/system/md5.h>
  
  using namespace mrpt::system;
  using namespace std;
  
  #include <cstdint>
  #include <cstdio>
  #include <cstring>
  #include <iostream>
  #include <string>
  
  // a small class for calculating MD5 hashes of strings or byte arrays
  // it is not meant to be fast or secure
  //
  // usage: 1) feed it blocks of uchars with update()
  //      2) finalize()
  //      3) get hexdigest() string
  //      or
  //      MD5(std::string).hexdigest()
  //
  // assumes that char is 8 bit and int is 32 bit
  class MD5
  {
     public:
  	using size_type = uint32_t;  // must be 32bit
  
  	MD5() = default;
  	MD5(const std::string& text);
  	void update(const unsigned char* buf, size_type length);
  	void update(const char* buf, size_type length);
  	MD5& finalize();
  	std::string hexdigest() const;
  	friend std::ostream& operator<<(std::ostream&, MD5 md5);
  
     private:
  	void init();
  	using uint1 = unsigned char;  //  8bit
  	using uint4 = unsigned int;  // 32bit
  	enum
  	{
  		blocksize = 64
  	};  // VC6 won't eat a const static int here
  
  	void transform(const uint1 block[blocksize]);
  	static void decode(uint4 output[], const uint1 input[], size_type len);
  	static void encode(uint1 output[], const uint4 input[], size_type len);
  
  	bool finalized{false};
  	// bytes that didn't fit in last 64 byte chunk
  	uint1 buffer[blocksize];
  	uint4 count[2] = {0, 0};  // 64bit counter for number of bits (lo, hi)
  	// load magic initialization constants:
  	uint4 state[4] = {0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476};
  	uint1 digest[16]{};  // the result
  
  	// low level logic operations
  	static inline uint4 F(uint4 x, uint4 y, uint4 z);
  	static inline uint4 G(uint4 x, uint4 y, uint4 z);
  	static inline uint4 H(uint4 x, uint4 y, uint4 z);
  	static inline uint4 I(uint4 x, uint4 y, uint4 z);
  	static inline uint4 rotate_left(uint4 x, int n);
  	static inline void FF(
  		uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac);
  	static inline void GG(
  		uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac);
  	static inline void HH(
  		uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac);
  	static inline void II(
  		uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac);
  };
  
  // Constants for MD5Transform routine.
  #define S11 7
  #define S12 12
  #define S13 17
  #define S14 22
  #define S21 5
  #define S22 9
  #define S23 14
  #define S24 20
  #define S31 4
  #define S32 11
  #define S33 16
  #define S34 23
  #define S41 6
  #define S42 10
  #define S43 15
  #define S44 21
  
  ///////////////////////////////////////////////
  
  // F, G, H and I are basic MD5 functions.
  inline MD5::uint4 MD5::F(uint4 x, uint4 y, uint4 z)
  {
  	return (x & y) | (~x & z);
  }
  
  inline MD5::uint4 MD5::G(uint4 x, uint4 y, uint4 z)
  {
  	return (x & z) | (y & ~z);
  }
  
  inline MD5::uint4 MD5::H(uint4 x, uint4 y, uint4 z) { return x ^ y ^ z; }
  inline MD5::uint4 MD5::I(uint4 x, uint4 y, uint4 z) { return y ^ (x | ~z); }
  // rotate_left rotates x left n bits.
  inline MD5::uint4 MD5::rotate_left(uint4 x, int n)
  {
  	return (x << n) | (x >> (32 - n));
  }
  
  // FF, GG, HH, and II transformations for rounds 1, 2, 3, and 4.
  // Rotation is separate from addition to prevent recomputation.
  inline void MD5::FF(
  	uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac)
  {
  	a = rotate_left(a + F(b, c, d) + x + ac, s) + b;
  }
  
  inline void MD5::GG(
  	uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac)
  {
  	a = rotate_left(a + G(b, c, d) + x + ac, s) + b;
  }
  
  inline void MD5::HH(
  	uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac)
  {
  	a = rotate_left(a + H(b, c, d) + x + ac, s) + b;
  }
  
  inline void MD5::II(
  	uint4& a, uint4 b, uint4 c, uint4 d, uint4 x, uint4 s, uint4 ac)
  {
  	a = rotate_left(a + I(b, c, d) + x + ac, s) + b;
  }
  
  //////////////////////////////////////////////
  
  // nifty shortcut ctor, compute MD5 for string and finalize it right away
  MD5::MD5(const std::string& text)
  {
  	init();
  	update(text.c_str(), text.length());
  	finalize();
  }
  
  //////////////////////////////
  
  void MD5::init() { *this = MD5(); }
  
  //////////////////////////////
  
  // decodes input (unsigned char) into output (uint4). Assumes len is a multiple
  // of 4.
  void MD5::decode(uint4 output[], const uint1 input[], size_type len)
  {
  	for (unsigned int i = 0, j = 0; j < len; i++, j += 4)
  		output[i] = ((uint4)input[j]) | (((uint4)input[j + 1]) << 8) |
  					(((uint4)input[j + 2]) << 16) |
  					(((uint4)input[j + 3]) << 24);
  }
  
  //////////////////////////////
  
  // encodes input (uint4) into output (unsigned char). Assumes len is
  // a multiple of 4.
  void MD5::encode(uint1 output[], const uint4 input[], size_type len)
  {
  	for (size_type i = 0, j = 0; j < len; i++, j += 4)
  	{
  		output[j] = input[i] & 0xff;
  		output[j + 1] = (input[i] >> 8) & 0xff;
  		output[j + 2] = (input[i] >> 16) & 0xff;
  		output[j + 3] = (input[i] >> 24) & 0xff;
  	}
  }
  
  //////////////////////////////
  
  // apply MD5 algo on a block
  void MD5::transform(const uint1 block[blocksize])
  {
  	uint4 a = state[0], b = state[1], c = state[2], d = state[3], x[16];
  	decode(x, block, blocksize);
  
  	/* Round 1 */
  	FF(a, b, c, d, x[0], S11, 0xd76aa478); /* 1 */
  	FF(d, a, b, c, x[1], S12, 0xe8c7b756); /* 2 */
  	FF(c, d, a, b, x[2], S13, 0x242070db); /* 3 */
  	FF(b, c, d, a, x[3], S14, 0xc1bdceee); /* 4 */
  	FF(a, b, c, d, x[4], S11, 0xf57c0faf); /* 5 */
  	FF(d, a, b, c, x[5], S12, 0x4787c62a); /* 6 */
  	FF(c, d, a, b, x[6], S13, 0xa8304613); /* 7 */
  	FF(b, c, d, a, x[7], S14, 0xfd469501); /* 8 */
  	FF(a, b, c, d, x[8], S11, 0x698098d8); /* 9 */
  	FF(d, a, b, c, x[9], S12, 0x8b44f7af); /* 10 */
  	FF(c, d, a, b, x[10], S13, 0xffff5bb1); /* 11 */
  	FF(b, c, d, a, x[11], S14, 0x895cd7be); /* 12 */
  	FF(a, b, c, d, x[12], S11, 0x6b901122); /* 13 */
  	FF(d, a, b, c, x[13], S12, 0xfd987193); /* 14 */
  	FF(c, d, a, b, x[14], S13, 0xa679438e); /* 15 */
  	FF(b, c, d, a, x[15], S14, 0x49b40821); /* 16 */
  
  	/* Round 2 */
  	GG(a, b, c, d, x[1], S21, 0xf61e2562); /* 17 */
  	GG(d, a, b, c, x[6], S22, 0xc040b340); /* 18 */
  	GG(c, d, a, b, x[11], S23, 0x265e5a51); /* 19 */
  	GG(b, c, d, a, x[0], S24, 0xe9b6c7aa); /* 20 */
  	GG(a, b, c, d, x[5], S21, 0xd62f105d); /* 21 */
  	GG(d, a, b, c, x[10], S22, 0x2441453); /* 22 */
  	GG(c, d, a, b, x[15], S23, 0xd8a1e681); /* 23 */
  	GG(b, c, d, a, x[4], S24, 0xe7d3fbc8); /* 24 */
  	GG(a, b, c, d, x[9], S21, 0x21e1cde6); /* 25 */
  	GG(d, a, b, c, x[14], S22, 0xc33707d6); /* 26 */
  	GG(c, d, a, b, x[3], S23, 0xf4d50d87); /* 27 */
  	GG(b, c, d, a, x[8], S24, 0x455a14ed); /* 28 */
  	GG(a, b, c, d, x[13], S21, 0xa9e3e905); /* 29 */
  	GG(d, a, b, c, x[2], S22, 0xfcefa3f8); /* 30 */
  	GG(c, d, a, b, x[7], S23, 0x676f02d9); /* 31 */
  	GG(b, c, d, a, x[12], S24, 0x8d2a4c8a); /* 32 */
  
  	/* Round 3 */
  	HH(a, b, c, d, x[5], S31, 0xfffa3942); /* 33 */
  	HH(d, a, b, c, x[8], S32, 0x8771f681); /* 34 */
  	HH(c, d, a, b, x[11], S33, 0x6d9d6122); /* 35 */
  	HH(b, c, d, a, x[14], S34, 0xfde5380c); /* 36 */
  	HH(a, b, c, d, x[1], S31, 0xa4beea44); /* 37 */
  	HH(d, a, b, c, x[4], S32, 0x4bdecfa9); /* 38 */
  	HH(c, d, a, b, x[7], S33, 0xf6bb4b60); /* 39 */
  	HH(b, c, d, a, x[10], S34, 0xbebfbc70); /* 40 */
  	HH(a, b, c, d, x[13], S31, 0x289b7ec6); /* 41 */
  	HH(d, a, b, c, x[0], S32, 0xeaa127fa); /* 42 */
  	HH(c, d, a, b, x[3], S33, 0xd4ef3085); /* 43 */
  	HH(b, c, d, a, x[6], S34, 0x4881d05); /* 44 */
  	HH(a, b, c, d, x[9], S31, 0xd9d4d039); /* 45 */
  	HH(d, a, b, c, x[12], S32, 0xe6db99e5); /* 46 */
  	HH(c, d, a, b, x[15], S33, 0x1fa27cf8); /* 47 */
  	HH(b, c, d, a, x[2], S34, 0xc4ac5665); /* 48 */
  
  	/* Round 4 */
  	II(a, b, c, d, x[0], S41, 0xf4292244); /* 49 */
  	II(d, a, b, c, x[7], S42, 0x432aff97); /* 50 */
  	II(c, d, a, b, x[14], S43, 0xab9423a7); /* 51 */
  	II(b, c, d, a, x[5], S44, 0xfc93a039); /* 52 */
  	II(a, b, c, d, x[12], S41, 0x655b59c3); /* 53 */
  	II(d, a, b, c, x[3], S42, 0x8f0ccc92); /* 54 */
  	II(c, d, a, b, x[10], S43, 0xffeff47d); /* 55 */
  	II(b, c, d, a, x[1], S44, 0x85845dd1); /* 56 */
  	II(a, b, c, d, x[8], S41, 0x6fa87e4f); /* 57 */
  	II(d, a, b, c, x[15], S42, 0xfe2ce6e0); /* 58 */
  	II(c, d, a, b, x[6], S43, 0xa3014314); /* 59 */
  	II(b, c, d, a, x[13], S44, 0x4e0811a1); /* 60 */
  	II(a, b, c, d, x[4], S41, 0xf7537e82); /* 61 */
  	II(d, a, b, c, x[11], S42, 0xbd3af235); /* 62 */
  	II(c, d, a, b, x[2], S43, 0x2ad7d2bb); /* 63 */
  	II(b, c, d, a, x[9], S44, 0xeb86d391); /* 64 */
  
  	state[0] += a;
  	state[1] += b;
  	state[2] += c;
  	state[3] += d;
  
  	// Zeroize sensitive information.
  	memset(x, 0, sizeof x);
  }
  
  //////////////////////////////
  
  // MD5 block update operation. Continues an MD5 message-digest
  // operation, processing another message block
  void MD5::update(const unsigned char input[], size_type length)
  {
  	// compute number of bytes mod 64
  	size_type index = count[0] / 8 % blocksize;
  
  	// Update number of bits
  	if ((count[0] += (length << 3)) < (length << 3)) count[1]++;
  	count[1] += (length >> 29);
  
  	// number of bytes we need to fill in buffer
  	size_type firstpart = 64 - index;
  
  	size_type i;
  
  	// transform as many times as possible.
  	if (length >= firstpart)
  	{
  		// fill buffer first, transform
  		memcpy(&buffer[index], input, firstpart);
  		transform(buffer);
  
  		// transform chunks of blocksize (64 bytes)
  		for (i = firstpart; i + blocksize <= length; i += blocksize)
  			transform(&input[i]);
  
  		index = 0;
  	}
  	else
  		i = 0;
  
  	// buffer remaining input
  	memcpy(&buffer[index], &input[i], length - i);
  }
  
  //////////////////////////////
  
  // for convenience provide a verson with signed char
  void MD5::update(const char input[], size_type length)
  {
  	update(reinterpret_cast<const unsigned char*>(input), length);
  }
  
  //////////////////////////////
  
  // MD5 finalization. Ends an MD5 message-digest operation, writing the
  // the message digest and zeroizing the context.
  MD5& MD5::finalize()
  {
  	static unsigned char padding[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};
  
  	if (!finalized)
  	{
  		// Save number of bits
  		unsigned char bits[8];
  		encode(bits, count, 8);
  
  		// pad out to 56 mod 64.
  		size_type index = count[0] / 8 % 64;
  		size_type padLen = (index < 56) ? (56 - index) : (120 - index);
  		update(padding, padLen);
  
  		// Append length (before padding)
  		update(bits, 8);
  
  		// Store state in digest
  		encode(digest, state, 16);
  
  		// Zeroize sensitive information.
  		memset(buffer, 0, sizeof buffer);
  		memset(count, 0, sizeof count);
  
  		finalized = true;
  	}
  
  	return *this;
  }
  
  //////////////////////////////
  
  // return hex representation of digest as string
  std::string MD5::hexdigest() const
  {
  	if (!finalized) return "";
  
  	char buf[33];
  	for (int i = 0; i < 16; i++) sprintf(buf + i * 2, "%02x", digest[i]);
  	buf[32] = 0;
  
  	return std::string(buf);
  }
  
  //////////////////////////////
  
  std::ostream& operator<<(std::ostream& out, MD5 md5)
  {
  	return out << md5.hexdigest();
  }
  
  //////////////////////////////
  
  std::string mrpt::system::md5(const std::string& str)
  {
  	MD5 md5 = MD5(str);
  	return md5.hexdigest();
  }
  
  std::string mrpt::system::md5(const unsigned char* data, const size_t len)
  {
  	ASSERT_(data);
  	MD5 md5;
  	md5.update(data, len);
  	md5.finalize();
  
  	return md5.hexdigest();
  }
  
  std::string mrpt::system::md5(const std::vector<uint8_t>& str)
  {
  	return mrpt::system::md5(&str[0], str.size());
  }
  