GB2312与UTF8互相转换

void GBToUTF8(const std::string& gb_str, std::string& result)
{
// 获得临时变量的大小
int str_len = MultiByteToWideChar(CP_ACP, 0, gb_str.c_str(), -1, NULL, 0);
    WCHAR *src_str = new WCHAR[str_len + 1];
    MultiByteToWideChar(CP_ACP, 0, gb_str.c_str(), -1, src_str, str_len);

// 获得临时变量的大小
    str_len = WideCharToMultiByte(CP_UTF8, 0, src_str, -1, NULL, 0, NULL, NULL);
char *dst_str = new char[str_len + 1];
    WideCharToMultiByte(CP_UTF8, 0, src_str, -1, dst_str, str_len, NULL, NULL);

    result = dst_str;

delete[]src_str;
delete[]dst_str;
}

void UTF8ToGB(const std::string& utf8_str, std::string& result)
{
// 获得临时变量的大小
int str_len = MultiByteToWideChar(CP_UTF8, 0, utf8_str.c_str(), -1, NULL, 0);
    WCHAR *src_str = new WCHAR[str_len + 1];
    ZeroMemory(src_str, sizeof(WCHAR)*(str_len + 1));
    MultiByteToWideChar(CP_UTF8, 0, utf8_str.c_str(), -1, src_str, str_len);

// 获得临时变量的大小
    str_len = WideCharToMultiByte(CP_ACP, 0, src_str, -1, NULL, 0, NULL, NULL);
char *dst_str = new char[str_len + 1];
    WideCharToMultiByte(CP_ACP, 0, src_str, -1, dst_str, str_len, NULL, NULL);

    result = dst_str;

delete[]src_str;
delete[]dst_str;
}