ansi、Unicode、Utf-8之间的转化

wstring ANSIToUnicode( const string& str )
{
	int len = 0;
	len = str.length();
	int unicodeLen = ::MultiByteToWideChar( CP_ACP,
		0,
		str.c_str(),
		-1,
		NULL,
		0 ); 
	wchar_t * pUnicode; 
	pUnicode = new wchar_t[unicodeLen+1]; 
	memset(pUnicode,0,(unicodeLen+1)*sizeof(wchar_t)); 
	::MultiByteToWideChar( CP_ACP,
		0,
		str.c_str(),
		-1,
		(LPWSTR)pUnicode,
		unicodeLen ); 
	wstring rt; 
	rt = ( wchar_t* )pUnicode;
	delete pUnicode; 
	return rt; 
}

string UnicodeToANSI( const wstring& str )
{
	char*     pElementText;
	int    iTextLen;
	// wide char to multi char
	iTextLen = WideCharToMultiByte( CP_ACP,
		0,
		str.c_str(),
		-1,
		NULL,
		0,
		NULL,
		NULL );
	pElementText = new char[iTextLen + 1];
	memset( ( void* )pElementText, 0, sizeof( char ) * ( iTextLen + 1 ) );
	::WideCharToMultiByte( CP_ACP,
		0,
		str.c_str(),
		-1,
		pElementText,
		iTextLen,
		NULL,
		NULL );
	string strText;
	strText = pElementText;
	delete[] pElementText;
	return strText;
}

wstring UTF8ToUnicode( const string& str )
{
	int len = 0;
	len = str.length();
	int unicodeLen = ::MultiByteToWideChar( CP_UTF8,
		0,
		str.c_str(),
		-1,
		NULL,
		0 ); 
	wchar_t * pUnicode; 
	pUnicode = new wchar_t[unicodeLen+1]; 
	memset(pUnicode,0,(unicodeLen+1)*sizeof(wchar_t)); 
	::MultiByteToWideChar( CP_UTF8,
		0,
		str.c_str(),
		-1,
		(LPWSTR)pUnicode,
		unicodeLen ); 
	wstring rt; 
	rt = ( wchar_t* )pUnicode;
	delete pUnicode; 
	return rt; 
}

string UnicodeToUTF8( const wstring& str )
{
	char*     pElementText;
	int    iTextLen;
	// wide char to multi char
	iTextLen = WideCharToMultiByte( CP_UTF8,
		0,
		str.c_str(),
		-1,
		NULL,
		0,
		NULL,
		NULL );
	pElementText = new char[iTextLen + 1];
	memset( ( void* )pElementText, 0, sizeof( char ) * ( iTextLen + 1 ) );
	::WideCharToMultiByte( CP_UTF8,
		0,
		str.c_str(),
		-1,
		pElementText,
		iTextLen,
		NULL,
		NULL );
	string strText;
	strText = pElementText;
	delete[] pElementText;
	return strText;
}

ansi、Unicode、Utf-8之间的转化

原文：http://blog.csdn.net/hzdiy/article/details/19132063