/*****************************************************************************************************
* Description:                 Bitcoin Block Hashing
*
* Author:                      Dengxue Yan, Washington University in St. Louis
*
* Email:                       Dengxue.Yan@wustl.edu
*
* Rev History:
*       <Author>        <Date>        <Hardware>     <Version>        <Description>
*     Dengxue Yan   10-20-2016 15:30       --           1.00             Create
*****************************************************************************************************/
//====================================================================================================
// Declaration of header files 
//----------------------------------------------------------------------------------------------------
// Lib headers
#include <stdio.h>
#include <memory.h>
#include <string.h>

// Self-defined headers
#include "sha256.h"

//====================================================================================================
// Functions implementation
//----------------------------------------------------------------------------------------------------
//----------------------------------------------------------------------------------------------------
// Interface functions
//----------------------------------------------------------------------------------------------------
//----------------------------------------------------------------------------------------------------
//   Function: BitcoinBlockHashing
//      Input: BYTE const *input: the bitcoin orginal array
//             int size: it should be 80 bytes
//     Output: BYTE *output: the output of the bitcoin block after hash algorithm
//                           the size should be SHA256_BLOCK_SIZE
//     Return: int: The status of function
//Description: Bitcoin Block Hashing Algorithm
//    <AUTHOR>        <MODIFYTIME>            <REASON>
//   Dengxue Yan     10-20-2016 15:30           Create
//----------------------------------------------------------------------------------------------------
int BitcoinBlockHashing(BYTE *output, BYTE const *input, int size)
{
	SHA256_CTX ctx;

    if ((NULL == output) || (NULL == input) || (80 != size)) 
    {
        printf("BitcoinBlockHashing Function entry check failed\n");
        return -1;
    }

    sha256_init(&ctx);
    sha256_update(&ctx, input, size);
    sha256_final(&ctx, output);

    sha256_init(&ctx);
    sha256_update(&ctx, output, SHA256_BLOCK_SIZE);
    sha256_final(&ctx, output);

    return 0;
}