package / tmp file usage ...

[Michael Meeks]

Hi Attila & Noel,

	Just moving this to the public dev list:

On 13/02/2023 07:43, Attila Szűcs wrote:
>      I plan to make test for zip64 ...
>      I plan to check if i could avoid temporal files creations during 
> export/import.. to mke a unit test that have 4gb sized files, but not 
> write 4gb to SSD in every test run.

	Noel might be interested in this. Noel, Attila suggests that every zip 
file we write we have to stream the full un-compressed data to /tmp 
files before compressing it. And these can be huge =)

	That is (I guess) necessary if we want to be able to seek backwards and 
edit eg. Excel binary streams or whatever - but for the vast majority of 
our one-pass, hyper-verbose XML generation it seems very silly - 
everything would be better if we could deflate compress that in another 
thread as we go I think ;-) perhaps then backed by a file but much 
smaller than the 4Gb+ of rather verbose ODS/ODF for a large spreadsheet 
that we need 64bit un-compressed stream sizes for.

	Noel - I wondered if you'd looked at this around saving performance - 
COOL at least does a lot more saving than loading - re: autosave =) I 
forget what we did in the past here.

	I imagine we could ask for a non-seekable zip stream somehow from the 
package code just for this case (?)

	Just a thought,
	
		Michael.

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