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jmacd / xdelta

open-source binary diff, delta/differential compression tools, VCDIFF/RFC 3284 delta compression
http://xdelta.org
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Conflicting Information on Minimum Value for -B/Source Buffer Size #263

Open lbacherle opened 3 years ago

lbacherle commented 3 years ago

Hey! Looked through all previous issues but couldn't find anything similar - I am looking into using xdelta for an embedded application, where RAM usage is important. The 'TuningMemoryBudget' page of the Wiki states a minimum value of 16KB for the -B option/minimum source buffer size. When I try to set 16 KB (using '-B 16384' on the Command Line Interface though, it raises an error, stating '-B: minimum value: 524288 [Bytes]', equaling 512 KB. Is the TuningMemoryBudget page out of date? Is it still possible to use values smaller than 512KB for the source buffer?

Thanks, Lisa

abolibibelot1980 commented 3 years ago

Apparently the captain has left the ship long ago and we the poor rats are left trying to survive with the scraps... é_è

I just tested with the old version 3.0t (which I happen to have found about a year ago in a patch archive on a japanese animation website -- that's how I first learned about xdelta and the very concept of delta compression) : it does work with -B 16384. It indeed no longer works with the current presumably stable release 3.0.11 (or 3.1.0). So if it's still important for your project I would suggest that you track down older versions and run tests until you find the best compromise (i.e. the most recent stable version which accepts a low enough value for -B).

Recently I've been suggested to try a similar tool called HDiffPatch, but I haven't tested it yet.

If you happen to have a clue or two about this one I'd be glad to have some useful feedback...