[bug #68281] Stream MAT v7 compression directly to output files

"Dmitri A. Sergatskov" <[email protected]> Sat, 25 Apr 2026 13:52:51 -0400 (EDT)

Newsgroups	gmane.comp.gnu.octave.bugs
Message-ID	<[email protected]>

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Follow-up Comment #2, bug #68281 (group octave):

The attached patch avoids writing temporary buffer prior to compression when
saving to mat-v7 format.
(file bug68281_mat7_20260425_100.cset)
Before:

octave:1> x = ones (2^31-2, 1, 'uint8');
octave:2> tic; save ('-binary', 'x.bin', 'x'); toc # reference
Elapsed time is 0.414707 seconds.
octave:3> tic; save ('-v7', 'x.mat7', 'x'); toc
Elapsed time is 2.30024 seconds.
octave:4> 

After:

octave:1> x = ones (2^31-2, 1, 'uint8');
octave:2> tic; save ('-v7', 'x.mat7', 'x'); toc
Elapsed time is 1.22243 seconds.


Dmitri.
-- 


(file #58510)

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Additional Item Attachment:

Name: bug68281_mat7_20260425_100.cset Size: 8.6KiB

<https://file.savannah.gnu.org/file/bug68281_mat7_20260425_100.cset?file_id=58510>


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