ASCII,UTF-8,Unicode字元串互相轉換

#include<string>
#include<windows.h>
#include<vector>
using namespace std;

//utf8 轉 Unicode


std::wstring Utf82Unicode(const std::string& utf8string)
{
	int widesize = ::MultiByteToWideChar(CP_UTF8, 0, utf8string.c_str(), -1, NULL, 0);
	if (widesize == ERROR_NO_UNICODE_TRANSLATION)
	{
		throw std::exception("Invalid UTF-8 sequence.");
    }
	if (widesize == 0)
	{
		throw std::exception("Error in conversion.");
	}
 
	std::vector<wchar_t> resultstring(widesize);
 
	int convresult = ::MultiByteToWideChar(CP_UTF8, 0, utf8string.c_str(), -1, &resultstring[0], widesize);
 
	if (convresult != widesize)
	{
		throw std::exception("La falla!");
	}
 
	return std::wstring(&resultstring[0]);
}


//unicode 轉為 ascii


std::string WideByte2Acsi(std::wstring& wstrcode)
{
	int asciisize = ::WideCharToMultiByte(CP_OEMCP, 0, wstrcode.c_str(), -1, NULL, 0, NULL, NULL);
	if (asciisize == ERROR_NO_UNICODE_TRANSLATION)
	{
		throw std::exception("Invalid UTF-8 sequence.");
	}
	if (asciisize == 0)
	{
		throw std::exception("Error in conversion.");
	}
    std::vector<char> resultstring(asciisize);
	int convresult =::WideCharToMultiByte(CP_OEMCP, 0, wstrcode.c_str(), -1, &resultstring[0], asciisize, NULL, NULL);
 
	if (convresult != asciisize)
	{
		throw std::exception("La falla!");
	}
 
    return std::string(&resultstring[0]);
}


 


//utf-8 轉 ascii


std::string UTF_82ASCII(std::string& strUtf8Code)
{
	std::string strRet("");
	//先把 utf8 轉為 unicode
	std::wstring wstr = Utf82Unicode(strUtf8Code);
	//最後把 unicode 轉為 ascii
	strRet = WideByte2Acsi(wstr);
	return strRet;
}


///


//ascii 轉 Unicode


std::wstring Acsi2WideByte(std::string& strascii)
{
	int widesize = MultiByteToWideChar (CP_ACP, 0, (char*)strascii.c_str(), -1, NULL, 0);
	if (widesize == ERROR_NO_UNICODE_TRANSLATION)
	{
		throw std::exception("Invalid UTF-8 sequence.");
	}
	if (widesize == 0)
	{
		throw std::exception("Error in conversion.");
	}
    std::vector<wchar_t> resultstring(widesize);
	int convresult = MultiByteToWideChar (CP_ACP, 0, (char*)strascii.c_str(), -1, &resultstring[0], widesize);


	if (convresult != widesize)
	{
		throw std::exception("La falla!");
	}
 
    return std::wstring(&resultstring[0]);
}


//Unicode 轉 Utf8


std::string Unicode2Utf8(const std::wstring& widestring)
{
	int utf8size = ::WideCharToMultiByte(CP_UTF8, 0, widestring.c_str(), -1, NULL, 0, NULL, NULL);
	if (utf8size == 0)
	{
		throw std::exception("Error in conversion.");
	}
 
	std::vector<char> resultstring(utf8size);
 
	int convresult = ::WideCharToMultiByte(CP_UTF8, 0, widestring.c_str(), -1, &resultstring[0], utf8size, NULL, NULL);
 
	if (convresult != utf8size)
	{
		throw std::exception("La falla!");
	}
 
	return std::string(&resultstring[0]);
}


//ascii 轉 Utf8


std::string ASCII2UTF_8(std::string& strAsciiCode)
{
	std::string strRet("");
	//先把 ascii 轉為 unicode
	std::wstring wstr = Acsi2WideByte(strAsciiCode);
	//最後把 unicode 轉為 utf8
	strRet = Unicode2Utf8(wstr);
	return strRet;
}