#include "stdafx.h"
#include "MD5Ex.h"

MD5Ex::MD5Ex()
{

}

MD5Ex::~MD5Ex()
{

}

string MD5Ex::ResultToHex(unsigned char digest[16], bool bUppercase)
{
	string strRetVal = "";
	for(int i = 0 ; i < 16; i++)
	{
		char buf[3] = {0};
		if(bUppercase)
			sprintf(buf, "%02X", digest[i]);
		else
			sprintf(buf, "%02x", digest[i]);
		strRetVal += buf;
	}
	return strRetVal;
}

void MD5Ex::OnFileProcessing(int nProgress, MemberFxn addr)
{
	void*			pThis	= addr.GetThis();
	unsigned long	Addr	= addr.GetAddr();

	/** the Calling Convention must be __stdcall or 
		thiscall (thiscall not a keyword),
		thiscall is the default calling convention used by C++ member functions 
	*/
	__asm
	{
		push	nProgress	;
	 	mov		ecx, pThis	;
		call	Addr		;
	}
}

string MD5Ex::MD5String(unsigned char *pData, unsigned long DataLen, bool bUppercase)
{
	MD5_CTX context;
	unsigned char digest[16];

	MD5Init		(&context);
	MD5Update	(&context, pData, DataLen);
	MD5Final	(digest, &context);

	return ResultToHex(digest, bUppercase);
}

string MD5Ex::MD5File(const char *FileName, bool bUppercase, MemberFxn addr)
{
	MD5_CTX context;
	FILE *file					= 0;
	int nFileBufSize			= 10240; // 文件緩沖區(qū)大小
	unsigned char *buffer		= new unsigned char[nFileBufSize + 1];
	unsigned char digest[16]	= {0};
	m_bTerminate				= false;
	
	try
	{
		if ((file = fopen (FileName, "rb")) == NULL)
		{
			m_strErr = "The file can't be opened!";
			goto ERR;
		}
		else 
		{
			int len					= 0;
			int ReadCount			= 0;
			unsigned long nFileSize = 0;

			// 獲取文件大小, 以下方式只能獲取小于2^32字節(jié)的文件大小
			{
				HANDLE hFile = CreateFile(FileName, NULL, FILE_SHARE_READ, NULL, OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL, 0);
				if(hFile== NULL)
				{
					m_strErr = "Get file size failed!";
					goto ERR;
				}
				nFileSize=::GetFileSize(hFile, NULL);
				CloseHandle(hFile);
			}

			if(!addr.IsNull())
				OnFileProcessing(0, addr);

			MD5Init(&context);

			while (len = fread (buffer, 1, nFileBufSize, file))
			{
				ReadCount++;

				if(m_bTerminate)
				{
					m_strErr = "User terminate calculate!";
					goto ERR;
				}

				MD5Update(&context, buffer, len);

				if(!addr.IsNull())
				{
					int n = (int)(nFileSize / 100);
					if(n <= 0)
						n = 1;
					OnFileProcessing((int)(nFileBufSize * ReadCount / n), addr);
				}

				memset(buffer, nFileBufSize + 1, 0);
			}

			MD5Final(digest, &context);

			if(!addr.IsNull())
				OnFileProcessing(100, addr);

			fclose (file);

			delete[] buffer;
			return ResultToHex(digest, bUppercase);
		}
	}
	catch(...)
	{
		m_strErr = "UnKnow error!";
		goto ERR;
	}

ERR:

	if(file != 0)
		fclose (file);
	delete[] buffer;
	return "";
}

void MD5Ex::StopCalculate()
{
	m_bTerminate = true;
}

string MD5Ex::GetError()
{
	return m_strErr;
}