[boost] asio file I/O

From: Felipe Magno de Almeida (felipe.m.almeida_at_[hidden])
Date: 2005-09-06 05:53:47

Hi boosters,

I've implemented asynchronous file IO for linux in asio using aio_* functions.
I created a class called basic_stream_file (and a typedef called
stream_file) with almost the same interface as basic_stream_socket.
But with read/write and async_read/async_write functions and an
aio_demuxer_service. I writed it for the 0.3.2 version.

For now to be able to use this new demuxer, is needed to create a
demuxer of type:    
asio::basic_demuxer<asio::detail::aio_demuxer_service>.

The implementation is attached.
I didnt had time to test it very much, but it seems to be working
okay. There are some problems that are related to aio_* in linux,
since it isnt completely implemented in today's kernels and isnt
implemented at all in 2.4.* kernels(there are patches however). And
the aio_* functions only work really asynchronous for now if used with
O_DIRECT and aligned buffers. But at least it could have a single
interface for AIO with files in Windows and Linux.
I'm planning to write asynchronous file I/O for windows with io
completions ports too. IMO it would be interesting to be able to have
a single demuxer in windows for file and socket AIO.

I'm sending attached a file that uses these classes as an example. It
must be linked with -laio and -lpthread and libaio must be installed.
(It wasnt in my slackware 10.1, dont know about the default setup of
other distributions).

Any feedback will be appreciated.
Thanks,
Felipe.

-- 
   Felipe Magno de Almeida
Developer from synergy and Computer Science student from State
University of Campinas(UNICAMP).
Unicamp: http://www.ic.unicamp.br
Synergy: http://www.synergy.com.br
"There is no dark side of the moon really. Matter of fact it's all dark."