I'd like to write compressed data to a file.
To improve performance, I want to use buffer.

I read some books, they all talk about 'character' stream.
But I think compressed data should be binary.

And, what buffer size if optimal?
How can I set the buffer size?

I need to checkpoint the buffer when
1) the buffer is full.
2) I have put all the data to the buffer.

Should I use standard library or boost?

Lambda a écrit :
> I'd like to write compressed data to a file.
> To improve performance, I want to use buffer.
>
> [snip]
> And, what buffer size if optimal?

That depends on your architecture, the algorithm you use ...

> How can I set the buffer size?

You cannot but you can set the buffer to use with a call to
streambuf::pubsetbuf().

> I need to checkpoint the buffer when
> 1) the buffer is full.

You can overload streambuf:verflow()

> 2) I have put all the data to the buffer.

I don't think you can know that but perhaps at flush() time.

> Should I use standard library or boost?

Boost.IOstream already provides compression and decompression in the
zlib, gzip and bzip2 formats. It would save you time. Using their
generic stream implementation might be a good idea; I don't know.

For more information about streambuf, see:
http://www.cplusplus.com/reference/iostream/streambuf/

--
Michael