UNICODE GBK UTF-8 编码互转（VC++）

1：UNICODE和GBK互转

wstring MBytesToWString(const char *lpcszString)
{
	int len = strlen(lpcszString);
	int unicodeLen = ::MultiByteToWideChar(CP_ACP, 0, lpcszString,  - 1, NULL, 0);
	wchar_t *pUnicode = new wchar_t[unicodeLen + 1];
	memset(pUnicode, 0, (unicodeLen + 1) *sizeof(wchar_t));
	::MultiByteToWideChar(CP_ACP, 0, lpcszString,  - 1, (LPWSTR)pUnicode, unicodeLen);
	wstring wString = (wchar_t *)pUnicode;
	delete [] pUnicode;
	return wString;
}

string WStringToMBytes(const wchar_t *lpwcszWString)
{
	char *pElementText;
	int iTextLen;
	// wide char to multi char
	iTextLen = ::WideCharToMultiByte(CP_ACP, 0, lpwcszWString,  - 1, NULL, 0, NULL, NULL);
	pElementText = new char[iTextLen + 1];
	memset((void *)pElementText, 0, (iTextLen + 1) *sizeof(char));
	::WideCharToMultiByte(CP_ACP, 0, lpwcszWString, 0, pElementText, iTextLen, NULL, NULL);
	string strReturn(pElementText);
	delete [] pElementText;
	return strReturn;
}

2：GBK和UTF-8互转

string GBKToUTF8(const string &strGBK)
{
	string strOutUTF8 = "";
	WCHAR *str1;
	int n = MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(),  - 1, NULL, 0);
	str1 = new WCHAR[n];
	MultiByteToWideChar(CP_ACP, 0, strGBK.c_str(),  - 1, str1, n);
	n = WideCharToMultiByte(CP_UTF8, 0, str1,  - 1, NULL, 0, NULL, NULL);
	char *str2 = new char[n];
	WideCharToMultiByte(CP_UTF8, 0, str1,  - 1, str2, n, NULL, NULL);
	strOutUTF8 = str2;
	delete [] str1;
	str1 = NULL;
	delete [] str2;
	str2 = NULL;
	return strOutUTF8;
}

string UTF8ToGBK(const string &strUTF8)
{
	int len = MultiByteToWideChar(CP_UTF8, 0, strUTF8.c_str(),  - 1, NULL, 0);
	WCHAR *wszGBK = new WCHAR[len + 1];
	memset(wszGBK, 0, (len+1)*sizeof(WCHAR));
	MultiByteToWideChar(CP_UTF8, 0, (LPCSTR)strUTF8.c_str(),  - 1, wszGBK, len);
	len = WideCharToMultiByte(CP_ACP, 0, wszGBK,  - 1, NULL, 0, NULL, NULL);
	char *szGBK = new char[len + 1];
	memset(szGBK, 0, len + 1);
	WideCharToMultiByte(CP_ACP, 0, wszGBK,  - 1, szGBK, len, NULL, NULL);
	//strUTF8 = szGBK;
	string strTemp(szGBK);
	delete [] szGBK;
	szGBK = NULL;
	delete [] wszGBK;
	wszGBK = NULL;
	return strTemp;
}

3：UNICODE和UTF-8互转

wstring UTF8ToWString(const char *lpcszString)
{
	int len = strlen(lpcszString);
	int unicodeLen = ::MultiByteToWideChar(CP_UTF8, 0, lpcszString,  - 1, NULL, 0);
	wchar_t *pUnicode;
	pUnicode = new wchar_t[unicodeLen + 1];
	memset((void *)pUnicode, 0, (unicodeLen + 1) *sizeof(wchar_t));
	::MultiByteToWideChar(CP_UTF8, 0, lpcszString,  - 1, (LPWSTR)pUnicode, unicodeLen);
	wstring wstrReturn(pUnicode);
	delete [] pUnicode;
	return wstrReturn;
}

string WStringToUTF8(const wchar_t *lpwcszWString)
{
	char *pElementText;
	int iTextLen = ::WideCharToMultiByte(CP_UTF8, 0, (LPWSTR)lpwcszWString,  - 1, NULL, 0, NULL, NULL);
	pElementText = new char[iTextLen + 1];
	memset((void *)pElementText, 0, (iTextLen + 1) *sizeof(char));
	::WideCharToMultiByte(CP_UTF8, 0, (LPWSTR)lpwcszWString,  - 1, pElementText, iTextLen, NULL, NULL);
	string strReturn(pElementText);
	delete [] pElementText;
	return strReturn;
}