fix: update customDictContentEnd after ZDICT_finalizeDictionary in COVER_selectDict - #4769
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VirajMishra1 wants to merge 1 commit into
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fix: update customDictContentEnd after ZDICT_finalizeDictionary in COVER_selectDict#4769VirajMishra1 wants to merge 1 commit into
VirajMishra1 wants to merge 1 commit into
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…VER_selectDict customDictContentEnd was computed from dictContentSize before the call to ZDICT_finalizeDictionary(), which overwrites dictContentSize with the actual finalized size (including the dictionary header). The stale pointer was then used in the shrinkDict loop to compute candidate content slices, referencing bytes past the true end of the custom content. Fix: recompute customDictContentEnd immediately after the call, once dictContentSize reflects the finalized value. Fixes facebook#4750
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Problem
In
COVER_selectDict(lib/dictBuilder/cover.c),customDictContentEndis computed on line 1055 from the inputdictContentSize:Then on line 1069,
ZDICT_finalizeDictionary()overwritesdictContentSizewith the actual finalized dictionary size (input content plus the header). The two values can differ, socustomDictContentEndis now stale.The stale pointer is used later in the
shrinkDictloop:This produces a wrong source pointer for candidate dictionaries when
shrinkDictis enabled.Fix
Recompute
customDictContentEndimmediately afterZDICT_finalizeDictionary()returns, oncedictContentSizereflects the finalized value.Fixes #4750