传世WPF文件读取c++源码

bool CWpf::WpfOpen(const char * strPathName,__int64 iOffset,DWORD dwOpenType)
{
	if(strPathName == NULL || dwOpenType == 0)
	{
		m_eWrLastError = EWR_PARA_ERROR;
		return false;
	}

	if(m_bSaving)
	{
		m_eWrLastError = EWR_FILE_SAVING;
		return false;
	}

	//先关闭当前打开的wpf文件
	WpfClose();

	m_strWpfDir = strPathName;
	replace(m_strWpfDir.begin(),m_strWpfDir.end(),'/','\\');
	size_t iPos = m_strWpfDir.find_last_of("\\");
	if (iPos != string::npos)
	{
		m_strWpfFileName = m_strWpfDir.substr(iPos + 1,m_strWpfDir.length() - iPos - 1);
		m_strWpfDir = m_strWpfDir.substr(0,iPos);
	}
	//打开或创建文件
	errno_t err = 0;
	if (dwOpenType & EWOT_RDWR)
	{
		err = 	_sopen_s(&(m_iFileHandle[EFT_MAIN]), strPathName, _O_BINARY | _O_RDWR , _SH_DENYWR,  _S_IREAD | _S_IWRITE );
		dwOpenType |= EWOT_LISTDIR;
	}
	else
	{
		err = 	_sopen_s(&(m_iFileHandle[EFT_MAIN]), strPathName, _O_BINARY | _O_RDONLY , /*_SH_DENYWR*/_SH_DENYNO,  _S_IREAD);
		if (dwOpenType & EWOT_READONLY)
		{
			dwOpenType |= EWOT_LISTHASH;
		}
	}

	if(err != 0)
	{
		m_eWrLastError = EWR_FILE_OPEN_FAIL;
		return false;
	}

	for (int i = EFT_THREAD ; i < EFT_NUM; i ++)
	{
		err = 	_sopen_s(&(m_iFileHandle[i]), strPathName, _O_BINARY | _O_RDONLY , _SH_DENYNO,  _S_IREAD);

		if(err != 0)
		{
			m_eWrLastError = EWR_FILE_OPEN_FAIL;
			return false;
		}
	}

	m_iWpfStartPos = iOffset;
	m_WpfHeader.dwMagic = 0;//防止有些文件长度不够sizeof(S_WpfHeader),取到默认值
	m_WpfHeader_Bak.dwMagic = 0;//防止有些文件长度不够sizeof(S_WpfHeader),取到默认值
	m_WpfHeader.bySavingHeader = TRUE;//防止有些文件长度不够sizeof(S_WpfHeader),取到默认值
	m_WpfHeader_Bak.bySavingHeader = TRUE;//防止有些文件长度不够sizeof(S_WpfHeader),取到默认值

	//读入文件头
	_lseeki64(m_iFileHandle[EFT_MAIN],m_iWpfStartPos,SEEK_SET);
	_read(m_iFileHandle[EFT_MAIN],&m_WpfHeader,sizeof(S_WpfHeader));

	//读入文件头备份
	_lseeki64(m_iFileHandle[EFT_MAIN],m_iWpfStartPos + sizeof(S_WpfHeader),SEEK_SET);
	_read(m_iFileHandle[EFT_MAIN],&m_WpfHeader_Bak,sizeof(S_WpfHeader));

	if(m_WpfHeader.bySavingHeader && m_WpfHeader_Bak.bySavingHeader)//该文件在创建的时候出现异常,如断点,程序崩溃等情况,没有正常写入头
	{
		return false;
	}

	//如果上次文件头没有正确保存,读取必份的文件
	if (m_WpfHeader.bySavingHeader)
	{
		m_WpfHeader = m_WpfHeader_Bak;
		m_bModifyed = true;//原来没有保存好,用了备份的,那么这次即使没有修改也要重新保存
	}

	m_WpfHeader_Disk = m_WpfHeader;

	if(m_WpfHeader.dwMagic != WPF_MAGIC)
	{
		m_eWrLastError = EWR_NOT_WPF_FILE;
		WpfClose();
		return false;
	}

	m_WpfHeader.bySavingHeader = FALSE;//理论上不可能出现文件头及备份文件头m_WpfHeader.bySavingHeader同时为TRUE,还是清一下标记
	m_dwOpenType = dwOpenType;

	//如果以写方式打开要求读入空闲块描述信息
	if ((m_dwOpenType & EWOT_RDWR) && m_WpfHeader.dwBlankBlockSize > 0)
	{
		PBlankBlock pBlock = new BlankBlock[m_WpfHeader.dwBlankBlockSize];
		_lseeki64(m_iFileHandle[EFT_MAIN],m_iWpfStartPos + m_WpfHeader.iBlankBlockPos,SEEK_SET);
		_read(m_iFileHandle[EFT_MAIN],pBlock,m_WpfHeader.dwBlankBlockSize * sizeof(BlankBlock));

		PBlankBlock p = pBlock;
		PBlankBlockNode pList = NULL,pList2 = NULL;

		pList = new BlankBlockNode();
		pList->blankBlock.dwStart = p->dwStart;
		pList->blankBlock.dwSize = p->dwSize;
		pList->pParent = NULL;
		pList->pNext = NULL;
		m_pBlankBlockList = pList;
		pList2 = pList;
		p ++;

		for (DWORD i = 1; i < m_WpfHeader.dwBlankBlockSize; i++,p++)
		{
			pList = new BlankBlockNode();
			pList->blankBlock.dwStart = p->dwStart;
			pList->blankBlock.dwSize = p->dwSize;
			pList->pParent = pList2;
			pList2->pNext = pList;
			pList2 = pList;
		}

		pList2->pNext = NULL;

		SAFE_DELETE_ARRAY(pBlock);
	}

	//载入文件分配表
	return WpfLoadFat();
}