zlib performance

[Daniel Kozák via Digitalmars-d-learn]

On Fri, 07 Aug 2015 07:19:43 +0000
yawniek via Digitalmars-d-learn <digitalmars-d-learn at puremagic.com>
wrote:

> hi,
> 
> unpacking files is kinda slow, probably i'm doing something wrong.
> 
> below code is about half the speed of gnu zcat on my os x machine.
> why?
> 
> why do i need to .dup the buffer?
> can i get rid of the casts?
> 
> 
> the chunk size has only a marginal influence.
> https://github.com/yannick/zcatd
> 
> import
>    std.zlib,
>    std.file,
>    std.stdio;
> 
> void main(string[] args)
> {
>    auto f = File(args[1], "r");
>    auto uncompressor = new UnCompress(HeaderFormat.gzip);
> 
>    foreach (ubyte[] buffer; f.byChunk(4096))
>    {
>            auto uncompressed = cast(immutable(string)) 
> uncompressor.uncompress(buffer.dup);
>            write(uncompressed);
>    }
> }
Which compiler and version. There has been some performance problem
with IO on OSX, it should be fixed in 2.068 release