Poco::FileStream std::fstream

[micheleselea]

Hi all, I recently done some tests about speed of writing file: in my case is a write to a samba share folder, but it's quite the same on a local drive. I found that if I write 24MB of data file with Poco::FileStream it takes about 2seconds, if I try with std::fstream it takes about 200 milliseconds
I think the reason is the "buffer class" between the FileStream and the WriteFile to disk (I'm using windows for these test), because it writes 4096 byte at a time (FileStreamBuf::BUFFER_SIZE). I think we already discuss here on an old post about it, but I don't remember what was the solution.
I think probably because std::fstream is c++ portable there's no reason to use Poco::FileStream or do you think that in some specific environment will be better using Poco::FileStream

[micheleselea]

Probably I realized that the Poco::FileStream has a better handle of error exceptions

[aleks-f]

#2475

[aleks-f]

I think the main reason for FileStream was to handle unicode file names

[micheleselea]

I changed the code to insert this constructor
FileStream(const std::string& path, std::ios::openmode mode = std::ios::out | std::ios::in, int BUFFER_SIZE = FileStreamBuf::BUFFER_SIZE);
If I use like this

const int bufferFIleStreamSize = 512 * 1024;
Poco::FileStream fFile(sFileName, mode, bufferFIleStreamSize);

the performance are comparable to std::fstream

Obviously I had to change even FileIOS as well

[matejk]

FileStreamBufhas function resizeBuffer that can be used to set own size of the file stream buffer. Use FileStream::rdbuf() to acquire the stream buffer.

[micheleselea]

I don't see resizeBuffer in my source code, from which version is there that function?

[matejk]

It was introduced in version 1.14.