string.cpp

用ATL写的操作数据库实例

		if (GetData() != _afxDataNil && GetData()->nRefs < 0)
			ATLTRACE("Warning: GetBuffer on locked CString creates unlocked CString!\n");
#endif
		// we have to grow the buffer
		CStringData* pOldData = GetData();
		int nOldLen = GetData()->nDataLength;   // AllocBuffer will tromp it
		if (nMinBufLength < nOldLen)
			nMinBufLength = nOldLen;
		AllocBuffer(nMinBufLength);
		memcpy(m_pchData, pOldData->data(), (nOldLen+1)*sizeof(TCHAR));
		GetData()->nDataLength = nOldLen;
		CString::Release(pOldData);
	}
	ATLASSERT(GetData()->nRefs <= 1);

	// return a pointer to the character storage for this string
	ATLASSERT(m_pchData != NULL);
	return m_pchData;
}

void CString::ReleaseBuffer(int nNewLength)
{
	CopyBeforeWrite();  // just in case GetBuffer was not called

	if (nNewLength == -1)
		nNewLength = lstrlen(m_pchData); // zero terminated

	ATLASSERT(nNewLength <= GetData()->nAllocLength);
	GetData()->nDataLength = nNewLength;
	m_pchData[nNewLength] = '\0';
}

LPTSTR CString::GetBufferSetLength(int nNewLength)
{
	ATLASSERT(nNewLength >= 0);

	GetBuffer(nNewLength);
	GetData()->nDataLength = nNewLength;
	m_pchData[nNewLength] = '\0';
	return m_pchData;
}

void CString::FreeExtra()
{
	ATLASSERT(GetData()->nDataLength <= GetData()->nAllocLength);
	if (GetData()->nDataLength != GetData()->nAllocLength)
	{
		CStringData* pOldData = GetData();
		AllocBuffer(GetData()->nDataLength);
		memcpy(m_pchData, pOldData->data(), pOldData->nDataLength*sizeof(TCHAR));
		ATLASSERT(m_pchData[GetData()->nDataLength] == '\0');
		CString::Release(pOldData);
	}
	ATLASSERT(GetData() != NULL);
}

LPTSTR CString::LockBuffer()
{
	LPTSTR lpsz = GetBuffer(0);
	GetData()->nRefs = -1;
	return lpsz;
}

void CString::UnlockBuffer()
{
	ATLASSERT(GetData()->nRefs == -1);
	if (GetData() != _afxDataNil)
		GetData()->nRefs = 1;
}

///////////////////////////////////////////////////////////////////////////////
// Commonly used routines (rarely used routines in STREX.CPP)

int CString::Find(TCHAR ch) const
{
	return Find(ch, 0);
}

int CString::Find(TCHAR ch, int nStart) const
{
	int nLength = GetData()->nDataLength;
	if (nStart >= nLength)
		return -1;

	// find first single character
	LPTSTR lpsz = _tcschr(m_pchData + nStart, (_TUCHAR)ch);

	// return -1 if not found and index otherwise
	return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);
}

int CString::FindOneOf(LPCTSTR lpszCharSet) const
{
	ATLASSERT(AfxIsValidString(lpszCharSet));
	LPTSTR lpsz = _tcspbrk(m_pchData, lpszCharSet);
	return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);
}

void CString::MakeUpper()
{
	CopyBeforeWrite();
	_tcsupr(m_pchData);
}

void CString::MakeLower()
{
	CopyBeforeWrite();
	_tcslwr(m_pchData);
}

void CString::MakeReverse()
{
	CopyBeforeWrite();
	_tcsrev(m_pchData);
}

void CString::SetAt(int nIndex, TCHAR ch)
{
	ATLASSERT(nIndex >= 0);
	ATLASSERT(nIndex < GetData()->nDataLength);

	CopyBeforeWrite();
	m_pchData[nIndex] = ch;
}

#ifndef _UNICODE
void CString::AnsiToOem()
{
	CopyBeforeWrite();
	::AnsiToOem(m_pchData, m_pchData);
}
void CString::OemToAnsi()
{
	CopyBeforeWrite();
	::OemToAnsi(m_pchData, m_pchData);
}
#endif
//------------------------------------------------------------------------------
//////////////////////////////////////////////////////////////////////////////
// More sophisticated construction

CString::CString(TCHAR ch, int nLength)
{
	Init();
	if (nLength >= 1)
	{
		AllocBuffer(nLength);
#ifdef _UNICODE
		for (int i = 0; i < nLength; i++)
			m_pchData[i] = ch;
#else
		memset(m_pchData, ch, nLength);
#endif
	}
}

CString::CString(LPCTSTR lpch, int nLength)
{
	Init();
	if (nLength != 0)
	{
		ATLASSERT(AfxIsValidAddress(lpch, nLength, FALSE));
		AllocBuffer(nLength);
		memcpy(m_pchData, lpch, nLength*sizeof(TCHAR));
	}
}

/////////////////////////////////////////////////////////////////////////////
// Special conversion constructors

#ifdef _UNICODE
CString::CString(LPCSTR lpsz, int nLength)
{
	Init();
	if (nLength != 0)
	{
		AllocBuffer(nLength);
		int n = ::MultiByteToWideChar(CP_ACP, 0, lpsz, nLength, m_pchData, nLength+1);
		ReleaseBuffer(n >= 0 ? n : -1);
	}
}
#else //_UNICODE
CString::CString(LPCWSTR lpsz, int nLength)
{
	Init();
	if (nLength != 0)
	{
		AllocBuffer(nLength*2);
		int n = ::WideCharToMultiByte(CP_ACP, 0, lpsz, nLength, m_pchData,
			(nLength*2)+1, NULL, NULL);
		ReleaseBuffer(n >= 0 ? n : -1);
	}
}
#endif //!_UNICODE

//////////////////////////////////////////////////////////////////////////////
// Assignment operators

const CString& CString::operator=(TCHAR ch)
{
	AssignCopy(1, &ch);
	return *this;
}

//////////////////////////////////////////////////////////////////////////////
// less common string expressions

CString AFXAPI operator+(const CString& string1, TCHAR ch)
{
	CString s;
	s.ConcatCopy(string1.GetData()->nDataLength, string1.m_pchData, 1, &ch);
	return s;
}

CString AFXAPI operator+(TCHAR ch, const CString& string)
{
	CString s;
	s.ConcatCopy(1, &ch, string.GetData()->nDataLength, string.m_pchData);
	return s;
}

//////////////////////////////////////////////////////////////////////////////
// Advanced manipulation

int CString::Delete(int nIndex, int nCount /* = 1 */)
{
	if (nIndex < 0)
		nIndex = 0;
	int nNewLength = GetData()->nDataLength;
	if (nCount > 0 && nIndex < nNewLength)
	{
		CopyBeforeWrite();
		int nBytesToCopy = nNewLength - (nIndex + nCount) + 1;

		memcpy(m_pchData + nIndex,
			m_pchData + nIndex + nCount, nBytesToCopy * sizeof(TCHAR));
		GetData()->nDataLength = nNewLength - nCount;
	}

	return nNewLength;
}

int CString::Insert(int nIndex, TCHAR ch)
{
	CopyBeforeWrite();

	if (nIndex < 0)
		nIndex = 0;

	int nNewLength = GetData()->nDataLength;
	if (nIndex > nNewLength)
		nIndex = nNewLength;
	nNewLength++;

	if (GetData()->nAllocLength < nNewLength)
	{
		CStringData* pOldData = GetData();
		LPTSTR pstr = m_pchData;
		AllocBuffer(nNewLength);
		memcpy(m_pchData, pstr, (pOldData->nDataLength+1)*sizeof(TCHAR));
		CString::Release(pOldData);
	}

	// move existing bytes down
	memcpy(m_pchData + nIndex + 1,
		m_pchData + nIndex, (nNewLength-nIndex)*sizeof(TCHAR));
	m_pchData[nIndex] = ch;
	GetData()->nDataLength = nNewLength;

	return nNewLength;
}

int CString::Insert(int nIndex, LPCTSTR pstr)
{
	if (nIndex < 0)
		nIndex = 0;

	int nInsertLength = SafeStrlen(pstr);
	int nNewLength = GetData()->nDataLength;
	if (nInsertLength > 0)
	{
		CopyBeforeWrite();
		if (nIndex > nNewLength)
			nIndex = nNewLength;
		nNewLength += nInsertLength;

		if (GetData()->nAllocLength < nNewLength)
		{
			CStringData* pOldData = GetData();
			LPTSTR pstr = m_pchData;
			AllocBuffer(nNewLength);
			memcpy(m_pchData, pstr, (pOldData->nDataLength+1)*sizeof(TCHAR));
			CString::Release(pOldData);
		}

		// move existing bytes down
		memcpy(m_pchData + nIndex + nInsertLength,
			m_pchData + nIndex,
			(nNewLength-nIndex-nInsertLength+1)*sizeof(TCHAR));
		memcpy(m_pchData + nIndex,
			pstr, nInsertLength*sizeof(TCHAR));
		GetData()->nDataLength = nNewLength;
	}

	return nNewLength;
}

int CString::Replace(TCHAR chOld, TCHAR chNew)
{
	int nCount = 0;

	// short-circuit the nop case
	if (chOld != chNew)
	{
		// otherwise modify each character that matches in the string
		CopyBeforeWrite();
		LPTSTR psz = m_pchData;
		LPTSTR pszEnd = psz + GetData()->nDataLength;
		while (psz < pszEnd)
		{
			// replace instances of the specified character only
			if (*psz == chOld)
			{
				*psz = chNew;
				nCount++;
			}
			psz = _tcsinc(psz);
		}
	}
	return nCount;
}

int CString::Replace(LPCTSTR lpszOld, LPCTSTR lpszNew)
{
	// can't have empty or NULL lpszOld

	int nSourceLen = SafeStrlen(lpszOld);
	if (nSourceLen == 0)
		return 0;
	int nReplacementLen = SafeStrlen(lpszNew);

	// loop once to figure out the size of the result string
	int nCount = 0;
	LPTSTR lpszStart = m_pchData;
	LPTSTR lpszEnd = m_pchData + GetData()->nDataLength;
	LPTSTR lpszTarget;
	while (lpszStart < lpszEnd)
	{
		while ((lpszTarget = _tcsstr(lpszStart, lpszOld)) != NULL)
		{
			nCount++;
			lpszStart = lpszTarget + nSourceLen;
		}
		lpszStart += lstrlen(lpszStart) + 1;
	}

	// if any changes were made, make them
	if (nCount > 0)
	{
		CopyBeforeWrite();

		// if the buffer is too small, just
		//   allocate a new buffer (slow but sure)
		int nOldLength = GetData()->nDataLength;
		int nNewLength =  nOldLength + (nReplacementLen-nSourceLen)*nCount;
		if (GetData()->nAllocLength < nNewLength || GetData()->nRefs > 1)
		{
			CStringData* pOldData = GetData();
			LPTSTR pstr = m_pchData;
			AllocBuffer(nNewLength);
			memcpy(m_pchData, pstr, pOldData->nDataLength*sizeof(TCHAR));
			CString::Release(pOldData);
		}
		// else, we just do it in-place
		lpszStart = m_pchData;
		lpszEnd = m_pchData + GetData()->nDataLength;

		// loop again to actually do the work
		while (lpszStart < lpszEnd)
		{
			while ( (lpszTarget = _tcsstr(lpszStart, lpszOld)) != NULL)
			{
				int nBalance = nOldLength - (lpszTarget - m_pchData + nSourceLen);
				memmove(lpszTarget + nReplacementLen, lpszTarget + nSourceLen,
					nBalance * sizeof(TCHAR));
				memcpy(lpszTarget, lpszNew, nReplacementLen*sizeof(TCHAR));
				lpszStart = lpszTarget + nReplacementLen;
				lpszStart[nBalance] = '\0';
				nOldLength += (nReplacementLen - nSourceLen);
			}
			lpszStart += lstrlen(lpszStart) + 1;
		}
		ATLASSERT(m_pchData[nNewLength] == '\0');
		GetData()->nDataLength = nNewLength;
	}

	return nCount;
}

int CString::Remove(TCHAR chRemove)
{
	CopyBeforeWrite();

	LPTSTR pstrSource = m_pchData;
	LPTSTR pstrDest = m_pchData;
	LPTSTR pstrEnd = m_pchData + GetData()->nDataLength;

	while (pstrSource < pstrEnd)
	{
		if (*pstrSource != chRemove)
		{
			*pstrDest = *pstrSource;
			pstrDest = _tcsinc(pstrDest);
		}
		pstrSource = _tcsinc(pstrSource);
	}
	*pstrDest = '\0';
	int nCount = pstrSource - pstrDest;
	GetData()->nDataLength -= nCount;

	return nCount;
}

//////////////////////////////////////////////////////////////////////////////
// Very simple sub-string extraction

CString CString::Mid(int nFirst) const
{
	return Mid(nFirst, GetData()->nDataLength - nFirst);
}

CString CString::Mid(int nFirst, int nCount) const
{
	// out-of-bounds requests return sensible things
	if (nFirst < 0)
		nFirst = 0;
	if (nCount < 0)
		nCount = 0;

	if (nFirst + nCount > GetData()->nDataLength)
		nCount = GetData()->nDataLength - nFirst;
	if (nFirst > GetData()->nDataLength)
		nCount = 0;

	ATLASSERT(nFirst >= 0);
	ATLASSERT(nFirst + nCount <= GetData()->nDataLength);

	// optimize case of returning entire string
	if (nFirst == 0 && nFirst + nCount == GetData()->nDataLength)
		return *this;

	CString dest;
	AllocCopy(dest, nCount, nFirst, 0);
	return dest;
}

CString CString::Right(int nCount) const
{
	if (nCount < 0)
		nCount = 0;
	if (nCount >= GetData()->nDataLength)
		return *this;

	CString dest;
	AllocCopy(dest, nCount, GetData()->nDataLength-nCount, 0);
	return dest;
}

CString CString::Left(int nCount) const
{
	if (nCount < 0)
		nCount = 0;
	if (nCount >= GetData()->nDataLength)
		return *this;

	CString dest;
	AllocCopy(dest, nCount, 0, 0);
	return dest;
}

// strspn equivalent
CString CString::SpanIncluding(LPCTSTR lpszCharSet) const
{
	ATLASSERT(AfxIsValidString(lpszCharSet));
	return Left(_tcsspn(m_pchData, lpszCharSet));
}

// strcspn equivalent
CString CString::SpanExcluding(LPCTSTR lpszCharSet) const
{
	ATLASSERT(AfxIsValidString(lpszCharSet));
	return Left(_tcscspn(m_pchData, lpszCharSet));
}

//////////////////////////////////////////////////////////////////////////////
// Finding

int CString::ReverseFind(TCHAR ch) const
{
	// find last single character
	LPTSTR lpsz = _tcsrchr(m_pchData, (_TUCHAR) ch);

	// return -1 if not found, distance from beginning otherwise
	return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);
}

// find a sub-string (like strstr)
int CString::Find(LPCTSTR lpszSub) const
{
	return Find(lpszSub, 0);
}

int CString::Find(LPCTSTR lpszSub, int nStart) const
{
	ATLASSERT(AfxIsValidString(lpszSub));

	int nLength = GetData()->nDataLength;
	if (nStart > nLength)
		return -1;

	// find first matching substring
	LPTSTR lpsz = _tcsstr(m_pchData + nStart, lpszSub);

	// return -1 for not found, distance from beginning otherwise
	return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);
}


/////////////////////////////////////////////////////////////////////////////
// CString formatting

#define TCHAR_ARG   TCHAR
#define WCHAR_ARG   WCHAR
#define CHAR_ARG    char


#define FORCE_ANSI      0x10000
#define FORCE_UNICODE   0x20000