text: #pragma once
  
  /*
  * Updated to C++, zedwood.com 2012
  * Based on Olivier Gay's version
  * See Modified BSD License below:
  *
  * FIPS 180-2 SHA-224/256/384/512 implementation
  * Issue date:  04/30/2005
  * http://www.ouah.org/ogay/sha2/
  *
  * 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 <string>
  
  class SHA256
  {
  protected:
  	typedef unsigned char uint8;
  	typedef unsigned int uint32;
  	typedef unsigned long long uint64;
  
  	const static uint32 sha256_k[];
  	static const unsigned int SHA224_256_BLOCK_SIZE = (512 / 8);
  public:
  	void init();
  	void update(const unsigned char *message, unsigned int len);
  	void final(unsigned char *digest);
  	static const unsigned int DIGEST_SIZE = (256 / 8);
  
  protected:
  	void transform(const unsigned char *message, unsigned int block_nb);
  	unsigned int m_tot_len;
  	unsigned int m_len;
  	unsigned char m_block[2 * SHA224_256_BLOCK_SIZE];
  	uint32 m_h[8];
  };
  
  std::string sha256(std::string input);
  
  #define SHA2_SHFR(x, n)    (x >> n)
  #define SHA2_ROTR(x, n)   ((x >> n) | (x << ((sizeof(x) << 3) - n)))
  #define SHA2_ROTL(x, n)   ((x << n) | (x >> ((sizeof(x) << 3) - n)))
  #define SHA2_CH(x, y, z)  ((x & y) ^ (~x & z))
  #define SHA2_MAJ(x, y, z) ((x & y) ^ (x & z) ^ (y & z))
  #define SHA256_F1(x) (SHA2_ROTR(x,  2) ^ SHA2_ROTR(x, 13) ^ SHA2_ROTR(x, 22))
  #define SHA256_F2(x) (SHA2_ROTR(x,  6) ^ SHA2_ROTR(x, 11) ^ SHA2_ROTR(x, 25))
  #define SHA256_F3(x) (SHA2_ROTR(x,  7) ^ SHA2_ROTR(x, 18) ^ SHA2_SHFR(x,  3))
  #define SHA256_F4(x) (SHA2_ROTR(x, 17) ^ SHA2_ROTR(x, 19) ^ SHA2_SHFR(x, 10))
  #define SHA2_UNPACK32(x, str)                 \
  {                                             \
      *((str) + 3) = (uint8) ((x)      );       \
      *((str) + 2) = (uint8) ((x) >>  8);       \
      *((str) + 1) = (uint8) ((x) >> 16);       \
      *((str) + 0) = (uint8) ((x) >> 24);       \
  }
  #define SHA2_PACK32(str, x)                   \
  {                                             \
      *(x) =   ((uint32) *((str) + 3)      )    \
             | ((uint32) *((str) + 2) <<  8)    \
             | ((uint32) *((str) + 1) << 16)    \
             | ((uint32) *((str) + 0) << 24);   \
  }
  