crc32ex.cpp

CRC32算法, 可以对字符串或文件进行CRC32计算, 带进度条.内含VC++6.0源码

/*
	Copyright 2006 - 2008, All Rights Reserved.

	CRC32类之扩展

	作者	- 张鲁夺(zhangluduo)
	MSN		- [e-mail]
	QQ群	- 34064264

	为所有爱我的人和我爱的人努力!
*/

#include "stdafx.h"
#include "CRC32Ex.h"

CRC32Ex::CRC32Ex()
{

}

CRC32Ex::~CRC32Ex()
{

}

void CRC32Ex::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		;
	}
}

void CRC32Ex::StopCalcFile()
{
	m_bTerminate = true;
}

string CRC32Ex::GetError()
{
	return m_strErr;
}

string CRC32Ex::GetCRC32FromFile(char* FileName, bool bUpper, MemberFxn addr)
{
	FILE *file							= 0;
	unsigned char buffer[BUFFER_SIZE]	= { 0 };
	m_bTerminate						= false;
	m_strErr							= "";
	
	try
	{
		if ((file = fopen (FileName, "rb")) == NULL)
		{
			m_strErr = "The file can't be opened!";
			return "";
		}
		else 
		{
			int len					= 0;
			int ReadCount			= 0;
			unsigned long nFileSize = 0;

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

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

			unsigned long CRCResult;
			CRCInit(CRCResult);

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

				if(m_bTerminate)
				{
					m_strErr = "User terminate calculate!";
					return "";
				}
				
				CRCUpdate((unsigned char *)buffer, len, CRCResult);

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

				memset(buffer, 0, BUFFER_SIZE);
			}

			CRCFinal(CRCResult);

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

			fclose (file);
			return ResultToHex(CRCResult, bUpper);
		}
	}
	catch(...)
	{
		m_strErr = "UnKnow error!";
		return "";
	}
}

string CRC32Ex::ResultToHex(unsigned long Result, bool bUpper)
{
	char buf[10] = { 0 };
	if(bUpper)
		sprintf(buf, "%.8X", Result);
	else 
		sprintf(buf, "%.8x", Result);
	return string(buf);
}

string CRC32Ex::GetCRC32FromBuffer	(unsigned char* pData, unsigned long DataLen, bool bUpper)
{
	m_strErr = "";
	unsigned long CRCResult;
	CRCInit(CRCResult);
	CRCUpdate(pData, DataLen, CRCResult);
	CRCFinal(CRCResult);
	return ResultToHex(CRCResult, bUpper);
}