LibGfx/CCITT: Make decoding of wide ccitt3-2d and ccitt-4 images faster#26083
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nico merged 1 commit intoSerenityOS:masterfrom Jul 31, 2025
Merged
LibGfx/CCITT: Make decoding of wide ccitt3-2d and ccitt-4 images faster#26083nico merged 1 commit intoSerenityOS:masterfrom
nico merged 1 commit intoSerenityOS:masterfrom
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`take_first()` on a Vector is O(n), meaning this function used to have
O(n^2) behavior in the width of an image.
We can just use a span instead, which can be be advanced in O(1) time.
Makes
pdf --debugging-stats ~/Downloads/ignition.pdf
go from 10.2s to 6.7s, 34% faster.
Makes the first 50 pages of
pdf --debugging-stats pdf-stuff/Mellor_ACTITC_10.pdf
go from 65.9s to 13.2s, 80% faster.
Fixes SerenityOS#26082.
LucasChollet
approved these changes
Jul 31, 2025
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LucasChollet
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LGTM, and thanks for the perf improvement!
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take_first()on a Vector is O(n), meaning this function used to have O(n^2) behavior in the width of an image.We can just use a span instead, which can be be advanced in O(1) time.
Makes
go from 10.2s to 6.7s, 34% faster.
Makes the first 50 pages of
go from 65.9s to 13.2s, 80% faster.
Fixes #26082.