关于c++对文件读写的封装

 namespace
 {
     UINT_T GetWriteSizeForNoBuf(UINT_T fsize)
     {
         UINT_T write_buf_size = ;
         if (fsize %  == )
         {
             write_buf_size = fsize;
         }
         else
         {
             write_buf_size = (fsize /  + )* ;
         }
         return write_buf_size;
     }

 }

 //将文件解析成路径，名称，类型
 bool CFileBak::ParseFilePath(const string& file_path_name, string& file_path, string& file_name, string& file_type)
 {
     size_t path_pos = file_path_name.find_last_of("/\\"); // 考虑/,\两种表示路径的方法
     if (path_pos == string::npos)
     {
         assert();
         return false;
     }
     file_path = file_path_name.substr(, path_pos);
     file_name = file_path_name.substr(path_pos + );
     size_t type_pos = file_name.find_last_of(".");
     if (type_pos != string::npos)
     {
         file_type = file_name.substr(type_pos + );
         file_name = file_name.substr(, type_pos);
     }
     return true;
 }

 bool CFileBak::ReadFile(std::string& buf, const std::string& file_path_name, const std::string& bak_name_tmp)
 {
     bool need_bak = true;
     FILE* ptr_file = NULL;
     size_t fsize = ;
     string bak_name = bak_name_tmp;
     bool tmp_false = false;
     do
     {
         fopen_s(&ptr_file, file_path_name.c_str(), "rb");
         if (NULL == ptr_file)
         {
             break;
         }

         //get file size
         fseek(ptr_file, , SEEK_END);
         fsize = (ftell(ptr_file));
         fseek(ptr_file, , SEEK_SET);
         if (fsize == )
         {
             fclose(ptr_file);
             ptr_file = NULL;
             break;
         }
         need_bak = false;
     } while (tmp_false);

     if (need_bak)
     {
         //assert(0); // 已经属于异常范畴了
         if (bak_name.empty())
         {
             string file_path;
             string file_name;
             string file_type;
             if (!ParseFilePath(file_path_name, file_path, file_name, file_type))
             {
                 assert();
                 return false;
             }
             bak_name = file_path + "/" + file_name + ".data";
         }

         fopen_s(&ptr_file, bak_name.c_str(), "rb");
         if (NULL == ptr_file)
         {
             //assert(0);
             return false;
         }

         //get file size
         fseek(ptr_file, , SEEK_END);
         fsize = (ftell(ptr_file));
         fseek(ptr_file, , SEEK_SET);
     }
     if (nullptr == ptr_file)
     {
         assert();
         return false;
     }

     if ( == fsize)
     {
         assert();
         fclose(ptr_file);
         return false;
     }

     auto_ptr<char> pBuf(new char[fsize]);
     memset(pBuf.get(), , fsize);
     size_t read_size = fread(pBuf.get(), , fsize, ptr_file);
     fclose(ptr_file);
     buf.assign(pBuf.get(), read_size);
     //buf = string(pBuf.get(), read_size);

     size_t n_pos = buf.find_last_not_of('\n');
     if (string::npos != n_pos)
     {
         buf = buf.substr(, n_pos + );
     }
     return true;
 }

 bool CFileBak::WriteFile(const std::string& file_name, const std::string& buf)
 {
     HANDLE hfile = CreateFileA(file_name.c_str(), GENERIC_WRITE | GENERIC_READ, , , OPEN_ALWAYS, FILE_FLAG_NO_BUFFERING, );
     if (INVALID_HANDLE_VALUE == hfile)
     {
         assert();
         CloseHandle(hfile);
         return false;
     }

     LARGE_INTEGER large_file_size;
     if (!GetFileSizeEx(hfile, &large_file_size))
     {
         assert();
         CloseHandle(hfile);
         return false;
     }
     size_t n_pos = buf.find_last_not_of('\n');

     string write_buf;
     if (string::npos != n_pos)
     {
         write_buf = buf.substr(, n_pos + );
     }
     else
     {
         write_buf = buf;
     }
     UINT_T write_size = GetWriteSizeForNoBuf(max(large_file_size.LowPart, static_cast<UINT_T>(write_buf.length())));
     if (write_size == )
     {
         assert();
         CloseHandle(hfile);
         return false;
     }

     auto_ptr<char> ptr_write_buf(new char[write_size]);
     memset(ptr_write_buf.get(), '\n', write_size); // 将换行写在文件中不影响使用，写0都会影响xml的功能
     memcpy(ptr_write_buf.get(), write_buf.c_str(), write_buf.length());

     DWORD dwret = ;
     ::WriteFile(hfile, ptr_write_buf.get(), write_size, &dwret, NULL);
     CloseHandle(hfile);
     return true;
 }