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#include <windows.h>
#include <string>

/// @brief asciiºÍunicodeÖ®¼äµÄ±àÂëת»»
size_t ascii_to_unicode(const char* src, wchar_t* dest, size_t dest_len, size_t src_len = 0)
{
	if(src_len == 0)
		src_len = strlen(src);
	return MultiByteToWideChar(CP_ACP, 0, src, static_cast<int>(src_len),
		dest, static_cast<int>(dest_len));
}

size_t unicode_to_ascii(const wchar_t* src, char* dest, size_t dest_len, size_t src_len = 0)
{
	if(src_len == 0)
		src_len = wcslen(src);
	return WideCharToMultiByte(CP_ACP, 0, src, static_cast<int>(src_len),
		dest, static_cast<int>(dest_len), NULL, NULL);
}

/// @brief utf8ºÍunicodeÖ®¼äµÄ±àÂëת»»
size_t utf8_to_unicode(const unsigned char* src, wchar_t* dest, size_t dest_len, size_t src_len = 0)
{
	if(src_len == 0)
		src_len = strlen((const char*)src);
	return MultiByteToWideChar(CP_UTF8, 0, (const char*)src, static_cast<int>(src_len),
		dest, static_cast<int>(dest_len));
}

size_t unicode_to_utf8(const wchar_t* src, unsigned char* dest, size_t dest_len, size_t src_len = 0)
{
	if(src_len == 0)
		src_len = wcslen(src);
	return WideCharToMultiByte(CP_UTF8, 0, src, static_cast<int>(src_len),
		(char*)dest, static_cast<int>(dest_len), NULL, NULL);
}

/// @brief asciiºÍutf8Ö®¼äµÄ±àÂëת»»
size_t ascii_to_utf8(const char* src, unsigned char* dest, size_t dest_len, size_t src_len = 0)
{
	if(src_len == 0)
		src_len = strlen(src);
	std::wstring unicode(src_len, 0);
	unicode.resize(ascii_to_unicode(src, const_cast<wchar_t*>(unicode.data()), unicode.size(), src_len));
	return unicode_to_utf8(unicode.data(), dest, dest_len, unicode.size());
}

size_t utf8_to_ascii(const unsigned char* src, char* dest, size_t dest_len, size_t src_len = 0)
{
	if(src_len == 0)
		src_len = strlen((const char*)src);
	std::wstring unicode(src_len * 2, 0);
	unicode.resize(utf8_to_unicode(src, const_cast<wchar_t*>(unicode.data()), unicode.size(), src_len));
	return unicode_to_ascii(unicode.data(), dest, dest_len, unicode.size());
}

/// @brief ÆÕͨ×Ö·û´®×ª¿í×Ö·û´®
std::wstring& to_wstring(const char* str, size_t len, std::wstring& ret)
{
	if(len == 0)
		len = strlen(str);
	ret.resize(len);
	ret.resize(ascii_to_unicode(str, const_cast<wchar_t*>(ret.data()), ret.size(), len));
	return ret;
}

std::wstring to_wstring(const char* str, size_t len = 0)
{
	std::wstring ret;
	return to_wstring(str, len, ret);
}

std::wstring to_wstring(const std::string& str)
{
	std::wstring ret;
	return to_wstring(str.data(), str.size(), ret);
}

std::wstring& to_wstring(const std::string& str, std::wstring& ret)
{
	return to_wstring(str.data(), str.size(), ret);
}

/// @brief ¿í×Ö·û´®×ªÆÕͨ×Ö·û´®
std::string& to_string(const wchar_t* str, size_t len, std::string& ret)
{
	if(len == 0)
		len = wcslen(str);
	ret.resize(len * 2);
	ret.resize(unicode_to_ascii(str, const_cast<char*>(ret.data()), ret.size(), len));
	return ret;
}

std::string to_string(const wchar_t* str, size_t len)
{
	std::string ret;
	return to_string(str, len, ret);
}

std::string to_string(const std::wstring& str)
{
	std::string ret;
	return to_string(str.data(), str.size(), ret);
}

std::string& to_string(const std::wstring& str, std::string& ret)
{
	return to_string(str.data(), str.size(), ret); 
}