C / C++ / MFC

BOOL CStdioFile::ReadString(CString& rString)
{
	ASSERT_VALID(this);

	rString = &afxChNil;    // empty string without deallocating
	const int nMaxSize = 128;
	LPTSTR lpsz = rString.GetBuffer(nMaxSize);
	LPTSTR lpszResult;
	int nLen = 0;
	for (;; )
	{
		lpszResult = _fgetts(lpsz, nMaxSize+1, m_pStream);
		rString.ReleaseBuffer();

		// handle error/eof case
		if (lpszResult == NULL && !feof(m_pStream))
		{
			clearerr(m_pStream);
			AfxThrowFileException(CFileException::generic, _doserrno,
				m_strFileName);
		}

		// if string is read completely or EOF
		if (lpszResult == NULL ||
			(nLen = lstrlen(lpsz)) < nMaxSize ||
			lpsz[nLen-1] == '\n')
			break;

		nLen = rString.GetLength();
		lpsz = rString.GetBuffer(nMaxSize + nLen) + nLen;
	}

	// remove '\n' from end of string if present
	lpsz = rString.GetBuffer(0);
	nLen = rString.GetLength();
	if (nLen != 0 && lpsz[nLen-1] == '\n')
		rString.GetBufferSetLength(nLen-1);

	return lpszResult != NULL;
}


void CStdioFile::WriteString(LPCTSTR lpsz)
{
	ASSERT(lpsz != NULL);
	ASSERT(m_pStream != NULL);

	if (_fputts(lpsz, m_pStream) == _TEOF)
		AfxThrowFileException(CFileException::diskFull, _doserrno, m_strFileName);
}