Re: C++ Deflate (zlib-like) library

From: Gavin Lambert (boost_at_[hidden])
Date: 2020-03-11 06:35:00

On 11/03/2020 14:17, Vinnie Falco wrote:
> "streambuf" is far too heavyweight to use as a low-level interface. I
> already pointed out that a codec needs to have as arguments not only
> the input and output "spans" but also return the number of bytes
> transacted for input and output.
> 
> signal-to-noise in this discussion is low...in a sense, zlib gets the
> crux of it right with the z_params:
> 
>      struct z_params
>      {
>         void const* next_in;
>         std::size_t avail_in;
>         std::size_t total_in = 0;
>         void* next_out;
>         std::size_t avail_out;
>         std::size_t total_out = 0;
>         int data_type = unknown;  // best guess about the data type:
> binary or text
>      };
> 
> The question is, can we do better than this? I'm certain that all
> answers which boil down to "copy std stream APIs" are wrong.

std::streambuf is almost that straightforward in its storage (albeit it 
uses more pointers, presumably related to supporting non-contiguous 
streams or something).

(And boost::asio::streambuf uses it, which is typically Boost.Asio's 
DynamicBuffer of choice.)

Other than Ye Olde Horrid Naming Conventions, the only particularly 
heavyweight thing in it that I can see is the locale.

Would you like std::streambuf better if it omitted the locale?  Or had 
better naming conventions?  Or is there some other objection to it?