std.zip expand: memory allocation failed

[Selim Ozel]

On Friday, 15 October 2021 at 20:41:36 UTC, Selim Ozel wrote:
> I am simply trying to unzip a compressed zip file slightly over 
> 1GB. The de-compressed size is about 4 GB.
>
> The code is very similar to what's explained in the 
> documentation [1] and it works for smaller files.
>
> Anyone has a solution? Memory mapping [2] previously solved 
> some part of my issue but expand is still throwing memory 
> allocation failure.
>
> Selim
>
> [1] https://dlang.org/phobos/std_zip.html
> [2] 
> https://forum.dlang.org/thread/mfnleztnwrbgivjvzvdp@forum.dlang.org

It turns out my computer was literally running out of memory as 
the file was getting unzipped. For some reason  to uncompress a 
1-gig file with uncompressed size of 4-gig, Zip Archive of D-Lang 
tries to use more than 16 gig of RAM. I don't know why. Maybe I 
missed something. I use a Windows 10, DMD v2.091 with x86_mscoff.

My work around was to call 7z from D Lang and do the compression 
over there. That worked like a charm.

It seems that zip.d [1] calls uncompress routine from zlib.d [2]. 
Would calling zlib uncompress by chunks solve this memory issue? 
Any ideas?

S

[1] https://github.com/dlang/phobos/blob/master/std/zip.d
[2] https://github.com/dlang/phobos/blob/master/std/zlib.d